Sample records for coronavirus rna synthesis

  1. Insights into RNA synthesis, capping, and proofreading mechanisms of SARS-coronavirus.

    PubMed

    Sevajol, Marion; Subissi, Lorenzo; Decroly, Etienne; Canard, Bruno; Imbert, Isabelle

    2014-12-19

    The successive emergence of highly pathogenic coronaviruses (CoVs) such as the Severe Acute Respiratory Syndrome (SARS-CoV) in 2003 and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in 2012 has stimulated a number of studies on the molecular biology. This research has provided significant new insight into functions and activities of the replication/transcription multi-protein complex. The latter directs both continuous and discontinuous RNA synthesis to replicate and transcribe the large coronavirus genome made of a single-stranded, positive-sense RNA of ∼30 kb. In this review, we summarize our current understanding of SARS-CoV enzymes involved in RNA biochemistry, such as the in vitro characterization of a highly active and processive RNA polymerase complex which can associate with methyltransferase and 3'-5' exoribonuclease activities involved in RNA capping, and RNA proofreading, respectively. The recent discoveries reveal fascinating RNA-synthesizing machinery, highlighting the unique position of coronaviruses in the RNA virus world. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Targeting Membrane-Bound Viral RNA Synthesis Reveals Potent Inhibition of Diverse Coronaviruses Including the Middle East Respiratory Syndrome Virus

    PubMed Central

    Bergström, Tomas; Kann, Nina; Adamiak, Beata; Hannoun, Charles; Kindler, Eveline; Jónsdóttir, Hulda R.; Muth, Doreen; Kint, Joeri; Forlenza, Maria; Müller, Marcel A.; Drosten, Christian; Thiel, Volker; Trybala, Edward

    2014-01-01

    Coronaviruses raise serious concerns as emerging zoonotic viruses without specific antiviral drugs available. Here we screened a collection of 16671 diverse compounds for anti-human coronavirus 229E activity and identified an inhibitor, designated K22, that specifically targets membrane-bound coronaviral RNA synthesis. K22 exerts most potent antiviral activity after virus entry during an early step of the viral life cycle. Specifically, the formation of double membrane vesicles (DMVs), a hallmark of coronavirus replication, was greatly impaired upon K22 treatment accompanied by near-complete inhibition of viral RNA synthesis. K22-resistant viruses contained substitutions in non-structural protein 6 (nsp6), a membrane-spanning integral component of the viral replication complex implicated in DMV formation, corroborating that K22 targets membrane bound viral RNA synthesis. Besides K22 resistance, the nsp6 mutants induced a reduced number of DMVs, displayed decreased specific infectivity, while RNA synthesis was not affected. Importantly, K22 inhibits a broad range of coronaviruses, including Middle East respiratory syndrome coronavirus (MERS–CoV), and efficient inhibition was achieved in primary human epithelia cultures representing the entry port of human coronavirus infection. Collectively, this study proposes an evolutionary conserved step in the life cycle of positive-stranded RNA viruses, the recruitment of cellular membranes for viral replication, as vulnerable and, most importantly, druggable target for antiviral intervention. We expect this mode of action to serve as a paradigm for the development of potent antiviral drugs to combat many animal and human virus infections. PMID:24874215

  3. Viral and Cellular mRNA Translation in Coronavirus-Infected Cells

    PubMed Central

    Nakagawa, K.; Lokugamage, K.G.; Makino, S.

    2017-01-01

    Coronaviruses have large positive-strand RNA genomes that are 5′ capped and 3′ polyadenylated. The 5′-terminal two-thirds of the genome contain two open reading frames (ORFs), 1a and 1b, that together make up the viral replicase gene and encode two large polyproteins that are processed by viral proteases into 15–16 nonstructural proteins, most of them being involved in viral RNA synthesis. ORFs located in the 3′-terminal one-third of the genome encode structural and accessory proteins and are expressed from a set of 5′ leader-containing subgenomic mRNAs that are synthesized by a process called discontinuous transcription. Coronavirus protein synthesis not only involves cap-dependent translation mechanisms but also employs regulatory mechanisms, such as ribosomal frameshifting. Coronavirus replication is known to affect cellular translation, involving activation of stress-induced signaling pathways, and employing viral proteins that affect cellular mRNA translation and RNA stability. This chapter describes our current understanding of the mechanisms involved in coronavirus mRNA translation and changes in host mRNA translation observed in coronavirus-infected cells. PMID:27712623

  4. Synthesis of coronavirus mRNAs: kinetics of inactivation of infectious bronchitis virus RNA synthesis by UV light. [Chickens

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stern, D.F.; Sefton, B.M.

    Infection of cells with the avian coronavirus infectious bronchitis virus results in the synthesis of five major subgenomic RNAs. These RNAs and the viral genome form a 3' coterminal nested set. We found that the rates of inactivation of synthesis of the RNAs by UV light were different and increased with the length of the transcript. These results show that each RNA is transcribed from a unique promoter and that extensive processing of the primary transcripts probably does not occur.

  5. Identification of cis-acting elements on positive-strand subgenomic mRNA required for the synthesis of negative-strand counterpart in bovine coronavirus.

    PubMed

    Yeh, Po-Yuan; Wu, Hung-Yi

    2014-07-30

    It has been demonstrated that, in addition to genomic RNA, sgmRNA is able to serve as a template for the synthesis of the negative-strand [(-)-strand] complement. However, the cis-acting elements on the positive-strand [(+)-strand] sgmRNA required for (-)-strand sgmRNA synthesis have not yet been systematically identified. In this study, we employed real-time quantitative reverse transcription polymerase chain reaction to analyze the cis-acting elements on bovine coronavirus (BCoV) sgmRNA 7 required for the synthesis of its (-)-strand counterpart by deletion mutagenesis. The major findings are as follows. (1) Deletion of the 5'-terminal leader sequence on sgmRNA 7 decreased the synthesis of the (-)-strand sgmRNA complement. (2) Deletions of the 3' untranslated region (UTR) bulged stem-loop showed no effect on (-)-strand sgmRNA synthesis; however, deletion of the 3' UTR pseudoknot decreased the yield of (-)-strand sgmRNA. (3) Nucleotides positioned from -15 to -34 of the sgmRNA 7 3'-terminal region are required for efficient (-)-strand sgmRNA synthesis. (4) Nucleotide species at the 3'-most position (-1) of sgmRNA 7 is correlated to the efficiency of (-)-strand sgmRNA synthesis. These results together suggest, in principle, that the 5'- and 3'-terminal sequences on sgmRNA 7 harbor cis-acting elements are critical for efficient (-)-strand sgmRNA synthesis in BCoV.

  6. Recognition of the murine coronavirus genomic RNA packaging signal depends on the second RNA-binding domain of the nucleocapsid protein.

    PubMed

    Kuo, Lili; Koetzner, Cheri A; Hurst, Kelley R; Masters, Paul S

    2014-04-01

    The coronavirus nucleocapsid (N) protein forms a helical ribonucleoprotein with the viral positive-strand RNA genome and binds to the principal constituent of the virion envelope, the membrane (M) protein, to facilitate assembly and budding. Besides these structural roles, N protein associates with a component of the replicase-transcriptase complex, nonstructural protein 3, at a critical early stage of infection. N protein has also been proposed to participate in the replication and selective packaging of genomic RNA and the transcription and translation of subgenomic mRNA. Coronavirus N proteins contain two structurally distinct RNA-binding domains, an unusual characteristic among RNA viruses. To probe the functions of these domains in the N protein of the model coronavirus mouse hepatitis virus (MHV), we constructed mutants in which each RNA-binding domain was replaced by its counterpart from the N protein of severe acute respiratory syndrome coronavirus (SARS-CoV). Mapping of revertants of the resulting chimeric viruses provided evidence for extensive intramolecular interactions between the two RNA-binding domains. Through analysis of viral RNA that was packaged into virions we identified the second of the two RNA-binding domains as a principal determinant of MHV packaging signal recognition. As expected, the interaction of N protein with M protein was not affected in either of the chimeric viruses. Moreover, the SARS-CoV N substitutions did not alter the fidelity of leader-body junction formation during subgenomic mRNA synthesis. These results more clearly delineate the functions of N protein and establish a basis for further exploration of the mechanism of genomic RNA packaging. This work describes the interactions of the two RNA-binding domains of the nucleocapsid protein of a model coronavirus, mouse hepatitis virus. The main finding is that the second of the two domains plays an essential role in recognizing the RNA structure that allows the selective

  7. Early endonuclease-mediated evasion of RNA sensing ensures efficient coronavirus replication

    PubMed Central

    Kindler, Eveline; Gil-Cruz, Cristina; Spanier, Julia; Li, Yize; Wilhelm, Jochen; Rabouw, Huib H.; Züst, Roland; Marti, Sabrina; Habjan, Matthias; Cervantes-Barragan, Luisa; Elliot, Ruth; Karl, Nadja; Gaughan, Christina; Silverman, Robert H.; Keller, Markus; Ludewig, Burkhard; Bergmann, Cornelia C.; Ziebuhr, John; Kalinke, Ulrich

    2017-01-01

    Coronaviruses are of veterinary and medical importance and include highly pathogenic zoonotic viruses, such as SARS-CoV and MERS-CoV. They are known to efficiently evade early innate immune responses, manifesting in almost negligible expression of type-I interferons (IFN-I). This evasion strategy suggests an evolutionary conserved viral function that has evolved to prevent RNA-based sensing of infection in vertebrate hosts. Here we show that the coronavirus endonuclease (EndoU) activity is key to prevent early induction of double-stranded RNA (dsRNA) host cell responses. Replication of EndoU-deficient coronaviruses is greatly attenuated in vivo and severely restricted in primary cells even during the early phase of the infection. In macrophages we found immediate induction of IFN-I expression and RNase L-mediated breakdown of ribosomal RNA. Accordingly, EndoU-deficient viruses can retain replication only in cells that are deficient in IFN-I expression or sensing, and in cells lacking both RNase L and PKR. Collectively our results demonstrate that the coronavirus EndoU efficiently prevents simultaneous activation of host cell dsRNA sensors, such as Mda5, OAS and PKR. The localization of the EndoU activity at the site of viral RNA synthesis–within the replicase complex—suggests that coronaviruses have evolved a viral RNA decay pathway to evade early innate and intrinsic antiviral host cell responses. PMID:28158275

  8. High-Resolution Analysis of Coronavirus Gene Expression by RNA Sequencing and Ribosome Profiling

    PubMed Central

    Jones, Joshua D.; Chung, Betty Y.-W.; Siddell, Stuart G.; Brierley, Ian

    2016-01-01

    Members of the family Coronaviridae have the largest genomes of all RNA viruses, typically in the region of 30 kilobases. Several coronaviruses, such as Severe acute respiratory syndrome-related coronavirus (SARS-CoV) and Middle East respiratory syndrome-related coronavirus (MERS-CoV), are of medical importance, with high mortality rates and, in the case of SARS-CoV, significant pandemic potential. Other coronaviruses, such as Porcine epidemic diarrhea virus and Avian coronavirus, are important livestock pathogens. Ribosome profiling is a technique which exploits the capacity of the translating ribosome to protect around 30 nucleotides of mRNA from ribonuclease digestion. Ribosome-protected mRNA fragments are purified, subjected to deep sequencing and mapped back to the transcriptome to give a global “snap-shot” of translation. Parallel RNA sequencing allows normalization by transcript abundance. Here we apply ribosome profiling to cells infected with Murine coronavirus, mouse hepatitis virus, strain A59 (MHV-A59), a model coronavirus in the same genus as SARS-CoV and MERS-CoV. The data obtained allowed us to study the kinetics of virus transcription and translation with exquisite precision. We studied the timecourse of positive and negative-sense genomic and subgenomic viral RNA production and the relative translation efficiencies of the different virus ORFs. Virus mRNAs were not found to be translated more efficiently than host mRNAs; rather, virus translation dominates host translation at later time points due to high levels of virus transcripts. Triplet phasing of the profiling data allowed precise determination of translated reading frames and revealed several translated short open reading frames upstream of, or embedded within, known virus protein-coding regions. Ribosome pause sites were identified in the virus replicase polyprotein pp1a ORF and investigated experimentally. Contrary to expectations, ribosomes were not found to pause at the ribosomal

  9. Structural and molecular basis of mismatch correction and ribavirin excision from coronavirus RNA.

    PubMed

    Ferron, François; Subissi, Lorenzo; Silveira De Morais, Ana Theresa; Le, Nhung Thi Tuyet; Sevajol, Marion; Gluais, Laure; Decroly, Etienne; Vonrhein, Clemens; Bricogne, Gérard; Canard, Bruno; Imbert, Isabelle

    2018-01-09

    Coronaviruses (CoVs) stand out among RNA viruses because of their unusually large genomes (∼30 kb) associated with low mutation rates. CoVs code for nsp14, a bifunctional enzyme carrying RNA cap guanine N7-methyltransferase (MTase) and 3'-5' exoribonuclease (ExoN) activities. ExoN excises nucleotide mismatches at the RNA 3'-end in vitro, and its inactivation in vivo jeopardizes viral genetic stability. Here, we demonstrate for severe acute respiratory syndrome (SARS)-CoV an RNA synthesis and proofreading pathway through association of nsp14 with the low-fidelity nsp12 viral RNA polymerase. Through this pathway, the antiviral compound ribavirin 5'-monophosphate is significantly incorporated but also readily excised from RNA, which may explain its limited efficacy in vivo. The crystal structure at 3.38 Å resolution of SARS-CoV nsp14 in complex with its cofactor nsp10 adds to the uniqueness of CoVs among RNA viruses: The MTase domain presents a new fold that differs sharply from the canonical Rossmann fold.

  10. The Nucleocapsid Protein of Coronaviruses Acts as a Viral Suppressor of RNA Silencing in Mammalian Cells.

    PubMed

    Cui, Lei; Wang, Haiying; Ji, Yanxi; Yang, Jie; Xu, Shan; Huang, Xingyu; Wang, Zidao; Qin, Lei; Tien, Po; Zhou, Xi; Guo, Deyin; Chen, Yu

    2015-09-01

    RNA interference (RNAi) is a process of eukaryotic posttranscriptional gene silencing that functions in antiviral immunity in plants, nematodes, and insects. However, recent studies provided strong supports that RNAi also plays a role in antiviral mechanism in mammalian cells. To combat RNAi-mediated antiviral responses, many viruses encode viral suppressors of RNA silencing (VSR) to facilitate their replication. VSRs have been widely studied for plant and insect viruses, but only a few have been defined for mammalian viruses currently. We identified a novel VSR from coronaviruses, a group of medically important mammalian viruses including Severe acute respiratory syndrome coronavirus (SARS-CoV), and showed that the nucleocapsid protein (N protein) of coronaviruses suppresses RNAi triggered by either short hairpin RNAs or small interfering RNAs in mammalian cells. Mouse hepatitis virus (MHV) is closely related to SARS-CoV in the family Coronaviridae and was used as a coronavirus replication model. The replication of MHV increased when the N proteins were expressed in trans, while knockdown of Dicer1 or Ago2 transcripts facilitated the MHV replication in mammalian cells. These results support the hypothesis that RNAi is a part of the antiviral immunity responses in mammalian cells. IMPORTANCE RNAi has been well known to play important antiviral roles from plants to invertebrates. However, recent studies provided strong supports that RNAi is also involved in antiviral response in mammalian cells. An important indication for RNAi-mediated antiviral activity in mammals is the fact that a number of mammalian viruses encode potent suppressors of RNA silencing. Our results demonstrate that coronavirus N protein could function as a VSR through its double-stranded RNA binding activity. Mutational analysis of N protein allowed us to find out the critical residues for the VSR activity. Using the MHV-A59 as the coronavirus replication model, we showed that ectopic expression

  11. Detection of group 1 coronaviruses in bats in North America

    USGS Publications Warehouse

    Dominguez, S.R.; O'Shea, T.J.; Oko, L.M.; Holmes, K.V.

    2007-01-01

    The epidemic of severe acute respiratory syndrome (SARS) was caused by a newly emerged coronavirus (SARS-CoV). Bats of several species in southern People's Republic of China harbor SARS-like CoVs and may be reservoir hosts for them. To determine whether bats in North America also harbor coronaviruses, we used reverse transcription-PCR to detect coronavirus RNA in bats. We found coronavirus RNA in 6 of 28 fecal specimens from bats of 2 of 7 species tested. The prevalence of viral RNA shedding was high: 17% in Eptesicus fuscus and 50% in Myotis occultus. Sequence analysis of a 440-bp amplicon in gene 1b showed that these Rocky Mountain bat coronaviruses formed 3 clusters in phylogenetic group 1 that were distinct from group 1 coronaviruses of Asian bats. Because of the potential for bat coronaviruses to cause disease in humans and animals, further surveillance and characterization of bat coronaviruses in North America are needed.

  12. Detection of potentially novel paramyxovirus and coronavirus viral RNA in bats and rats in the Mekong Delta region of southern Viet Nam.

    PubMed

    Berto, A; Anh, P H; Carrique-Mas, J J; Simmonds, P; Van Cuong, N; Tue, N T; Van Dung, N; Woolhouse, M E; Smith, I; Marsh, G A; Bryant, J E; Thwaites, G E; Baker, S; Rabaa, M A

    2018-02-01

    Bats and rodents are being increasingly recognized as reservoirs of emerging zoonotic viruses. Various studies have investigated bat viruses in tropical regions, but to date there are no data regarding viruses with zoonotic potential that circulate in bat and rat populations in Viet Nam. To address this paucity of data, we sampled three bat farms and three wet markets trading in rat meat in the Mekong Delta region of southern Viet Nam. Faecal and urine samples were screened for the presence of RNA from paramyxoviruses, coronaviruses and filoviruses. Paramyxovirus RNA was detected in 4 of 248 (1%) and 11 of 222 (4.9%) bat faecal and urine samples, respectively. Coronavirus RNA was detected in 55 of 248 (22%) of bat faecal samples; filovirus RNA was not detected in any of the bat samples. Further, coronavirus RNA was detected in 12 of 270 (4.4%) of rat faecal samples; all samples tested negative for paramyxovirus. Phylogenetic analysis revealed that the bat paramyxoviruses and bat and rat coronaviruses were related to viruses circulating in bat and rodent populations globally, but showed no cross-species mixing of viruses between bat and rat populations within Viet Nam. Our study shows that potentially novel variants of paramyxoviruses and coronaviruses commonly circulate in bat and rat populations in Viet Nam. Further characterization of the viruses and additional human and animal surveillance is required to evaluate the likelihood of viral spillover and to assess whether these viruses pose a risk to human health. © 2017 The Authors. Zoonoses and Public Health Published by Blackwell Verlag GmbH.

  13. Inhibition of Cytosolic Phospholipase A2α Impairs an Early Step of Coronavirus Replication in Cell Culture.

    PubMed

    Müller, Christin; Hardt, Martin; Schwudke, Dominik; Neuman, Benjamin W; Pleschka, Stephan; Ziebuhr, John

    2018-02-15

    Coronavirus replication is associated with intracellular membrane rearrangements in infected cells, resulting in the formation of double-membrane vesicles (DMVs) and other membranous structures that are referred to as replicative organelles (ROs). The latter provide a structural scaffold for viral replication/transcription complexes (RTCs) and help to sequester RTC components from recognition by cellular factors involved in antiviral host responses. There is increasing evidence that plus-strand RNA (+RNA) virus replication, including RO formation and virion morphogenesis, affects cellular lipid metabolism and critically depends on enzymes involved in lipid synthesis and processing. Here, we investigated the role of cytosolic phospholipase A 2 α (cPLA 2 α) in coronavirus replication using a low-molecular-weight nonpeptidic inhibitor, pyrrolidine-2 (Py-2). The inhibition of cPLA 2 α activity, which produces lysophospholipids (LPLs) by cleaving at the sn -2 position of phospholipids, had profound effects on viral RNA and protein accumulation in human coronavirus 229E-infected Huh-7 cells. Transmission electron microscopy revealed that DMV formation in infected cells was significantly reduced in the presence of the inhibitor. Furthermore, we found that (i) viral RTCs colocalized with LPL-containing membranes, (ii) cellular LPL concentrations were increased in coronavirus-infected cells, and (iii) this increase was diminished in the presence of the cPLA 2 α inhibitor Py-2. Py-2 also displayed antiviral activities against other viruses representing the Coronaviridae and Togaviridae families, while members of the Picornaviridae were not affected. Taken together, the study provides evidence that cPLA 2 α activity is critically involved in the replication of various +RNA virus families and may thus represent a candidate target for broad-spectrum antiviral drug development. IMPORTANCE Examples of highly conserved RNA virus proteins that qualify as drug targets for broad

  14. Detection and Phylogenetic Analysis of Group 1 Coronaviruses in South American Bats

    PubMed Central

    Foster, Jerome E.; Zhu, Hua Chen; Zhang, Jin Xia; Smith, Gavin J.D.; Thompson, Nadin; Auguste, Albert J.; Ramkissoon, Vernie; Adesiyun, Abiodun A.; Guan, Yi

    2008-01-01

    Bat coronaviruses (Bt-CoVs) are thought to be the precursors of severe acute respiratory syndrome coronavirus. We detected Bt-CoVs in 2 bat species from Trinidad. Phylogenetic analysis of the RNA-dependent RNA polymerase gene and helicase confirmed them as group 1 coronaviruses. PMID:19046513

  15. Nucleocapsid protein-dependent assembly of the RNA packaging signal of Middle East respiratory syndrome coronavirus.

    PubMed

    Hsin, Wei-Chen; Chang, Chan-Hua; Chang, Chi-You; Peng, Wei-Hao; Chien, Chung-Liang; Chang, Ming-Fu; Chang, Shin C

    2018-05-24

    Middle East respiratory syndrome coronavirus (MERS-CoV) consists of a positive-sense, single-stranded RNA genome and four structural proteins: the spike, envelope, membrane, and nucleocapsid protein. The assembly of the viral genome into virus particles involves viral structural proteins and is believed to be mediated through recognition of specific sequences and RNA structures of the viral genome. A culture system for the production of MERS coronavirus-like particles (MERS VLPs) was determined and established by electron microscopy and the detection of coexpressed viral structural proteins. Using the VLP system, a 258-nucleotide RNA fragment, which spans nucleotides 19,712 to 19,969 of the MERS-CoV genome (designated PS258(19712-19969) ME ), was identified to function as a packaging signal. Assembly of the RNA packaging signal into MERS VLPs is dependent on the viral nucleocapsid protein. In addition, a 45-nucleotide stable stem-loop substructure of the PS258(19712-19969) ME interacted with both the N-terminal domain and the C-terminal domain of the viral nucleocapsid protein. Furthermore, a functional SARS-CoV RNA packaging signal failed to assemble into the MERS VLPs, which indicated virus-specific assembly of the RNA genome. A MERS-oV RNA packaging signal was identified by the detection of GFP expression following an incubation of MERS VLPs carrying the heterologous mRNA GFP-PS258(19712-19969) ME with virus permissive Huh7 cells. The MERS VLP system could help us in understanding virus infection and morphogenesis.

  16. [Human coronavirus infections: importance and diagnosis].

    PubMed

    Vabret, A; Brouard, J; Petitjean, J; Eugene-Ruellan, G; Freymuth, F

    1998-11-14

    POORLY-KNOWN VIRUS: Coronaviruses, so named because of their sun-ray-like aspect, were discovered in the sixties. The biology of these RNA viruses is complex and poorly understood. KNOWN PATHOGENS: Coronaviruses are known pathogens in veterinary medicine, causing disease states in several domestic species. In human medicine, they can cause benign respiratory infections, but few laboratories include coronaviruses in their routine diagnostic tests. SUSPECTED PATHOGENS: There is some data in the literature suggesting coronaviruses might be implicated in more severe diseases including multiple sclerosis, necrotizing enterocolitis, and lower respiratory tract infections, particularly in infants. IMPROVING DIAGNOSTIC METHODS: Due to the lack of reliable and sensitive diagnostic techniques, it is impossible to date to correctly assess the medical impact of these ubiquitous and endemic viruses. Molecular biology techniques enabling detection of human coronavirus infections should be applied to verifying the suspected implication of these viruses in diverse disease states.

  17. Transmissible Gastroenteritis Coronavirus Genome Packaging Signal Is Located at the 5′ End of the Genome and Promotes Viral RNA Incorporation into Virions in a Replication-Independent Process

    PubMed Central

    Morales, Lucia; Mateos-Gomez, Pedro A.; Capiscol, Carmen; del Palacio, Lorena; Sola, Isabel

    2013-01-01

    Preferential RNA packaging in coronaviruses involves the recognition of viral genomic RNA, a crucial process for viral particle morphogenesis mediated by RNA-specific sequences, known as packaging signals. An essential packaging signal component of transmissible gastroenteritis coronavirus (TGEV) has been further delimited to the first 598 nucleotides (nt) from the 5′ end of its RNA genome, by using recombinant viruses transcribing subgenomic mRNA that included potential packaging signals. The integrity of the entire sequence domain was necessary because deletion of any of the five structural motifs defined within this region abrogated specific packaging of this viral RNA. One of these RNA motifs was the stem-loop SL5, a highly conserved motif in coronaviruses located at nucleotide positions 106 to 136. Partial deletion or point mutations within this motif also abrogated packaging. Using TGEV-derived defective minigenomes replicated in trans by a helper virus, we have shown that TGEV RNA packaging is a replication-independent process. Furthermore, the last 494 nt of the genomic 3′ end were not essential for packaging, although this region increased packaging efficiency. TGEV RNA sequences identified as necessary for viral genome packaging were not sufficient to direct packaging of a heterologous sequence derived from the green fluorescent protein gene. These results indicated that TGEV genome packaging is a complex process involving many factors in addition to the identified RNA packaging signal. The identification of well-defined RNA motifs within the TGEV RNA genome that are essential for packaging will be useful for designing packaging-deficient biosafe coronavirus-derived vectors and providing new targets for antiviral therapies. PMID:23966403

  18. Transduction of hematopoietic stem cells to stimulate RNA interference against feline infectious peritonitis.

    PubMed

    Anis, Eman A; Dhar, Madhu; Legendre, Alfred M; Wilkes, Rebecca P

    2017-06-01

    Objectives The goals of the study were: (1) to develop and evaluate non-replicating lentivirus vectors coding for feline coronavirus (FCoV)-specific micro (mi)RNA as a potential antiviral therapy for feline infectious peritonitis (FIP); (2) to assess the feasibility of transducing hematopoietic stem cells (HSCs) with ex vivo introduction of the miRNA-expressing lentivirus vector; and (3) to assess the ability of the expressed miRNA to inhibit FCoV replication in HSCs in vitro. Methods HSCs were obtained from feline bone marrow and replicated in vitro. Three lentiviruses were constructed, each expressing a different anti-FCoV miRNA. HSCs were stably transduced with the miRNA-expressing lentivirus vector that produced the most effective viral inhibition in a feline cell line. The effectiveness of the transduction and the expression of anti-FCoV miRNA were tested by infecting the HSCs with two different strains of FCoV. The inhibition of coronavirus replication was determined by relative quantification of the inhibition of intracellular viral genomic RNA synthesis using real-time, reverse-transcription PCR. The assessment of virus replication inhibition was determined via titration of extracellular virus using the TCID 50 assay. Results Inhibition of FCoV was most significant in feline cells expressing miRNA-L2 that targeted the viral leader sequence, 48 h postinfection. miRNA-L2 expression in stably transduced HSCs resulted in 90% and 92% reductions in FIPV WSU 79-1146 genomic RNA synthesis and extracellular virus production, respectively, as well as 74% and 80% reduction in FECV WSU 79-1683 genomic RNA synthesis and extracellular virus production, respectively, as compared with an infected negative control sample producing non-targeting miRNA. Conclusions and relevance These preliminary results show that genetic modification of HSCs for constitutive production of anti-coronavirus miRNA will reduce FCoV replication.

  19. Genetic Characteristics of Coronaviruses from Korean Bats in 2016.

    PubMed

    Lee, Saemi; Jo, Seong-Deok; Son, Kidong; An, Injung; Jeong, Jipseol; Wang, Seung-Jun; Kim, Yongkwan; Jheong, Weonhwa; Oem, Jae-Ku

    2018-01-01

    Bats have increasingly been recognized as the natural reservoir of severe acute respiratory syndrome (SARS), coronavirus, and other coronaviruses found in mammals. However, little research has been conducted on bat coronaviruses in South Korea. In this study, bat samples (332 oral swabs, 245 fecal samples, 38 urine samples, and 57 bat carcasses) were collected at 33 natural bat habitat sites in South Korea. RT-PCR and sequencing were performed for specific coronavirus genes to identify the bat coronaviruses in different bat samples. Coronaviruses were detected in 2.7% (18/672) of the samples: 13 oral swabs from one species of the family Rhinolophidae, and four fecal samples and one carcass (intestine) from three species of the family Vespertiliodae. To determine the genetic relationships of the 18 sequences obtained in this study and previously known coronaviruses, the nucleotide sequences of a 392-nt region of the RNA-dependent RNA polymerase (RdRp) gene were analyzed phylogenetically. Thirteen sequences belonging to SARS-like betacoronaviruses showed the highest nucleotide identity (97.1-99.7%) with Bat-CoV-JTMC15 reported in China. The other five sequences were most similar to MERS-like betacoronaviruses. Four nucleotide sequences displayed the highest identity (94.1-95.1%) with Bat-CoV-HKU5 from Hong Kong. The one sequence from a carcass showed the highest nucleotide identity (99%) with Bat-CoV-SC2013 from China. These results suggest that careful surveillance of coronaviruses from bats should be continued, because animal and human infections may result from the genetic variants present in bat coronavirus reservoirs.

  20. Genotyping bovine coronaviruses.

    USDA-ARS?s Scientific Manuscript database

    Bovine coronaviruses (BoCV) are enveloped, single-stranded, positive-sense RNA viruses of the Coronaviridae family. Infection is associated with enteritis and pneumonia in calves and Winter Dysentery in adult cattle. Strains, isolated more than 50 years ago, are used in vaccines and as laboratory ...

  1. Achieving a golden mean: mechanisms by which coronaviruses ensure synthesis of the correct stoichiometric ratios of viral proteins.

    PubMed

    Plant, Ewan P; Rakauskaite, Rasa; Taylor, Deborah R; Dinman, Jonathan D

    2010-05-01

    In retroviruses and the double-stranded RNA totiviruses, the efficiency of programmed -1 ribosomal frameshifting is critical for ensuring the proper ratios of upstream-encoded capsid proteins to downstream-encoded replicase enzymes. The genomic organizations of many other frameshifting viruses, including the coronaviruses, are very different, in that their upstream open reading frames encode nonstructural proteins, the frameshift-dependent downstream open reading frames encode enzymes involved in transcription and replication, and their structural proteins are encoded by subgenomic mRNAs. The biological significance of frameshifting efficiency and how the relative ratios of proteins encoded by the upstream and downstream open reading frames affect virus propagation has not been explored before. Here, three different strategies were employed to test the hypothesis that the -1 PRF signals of coronaviruses have evolved to produce the correct ratios of upstream- to downstream-encoded proteins. Specifically, infectious clones of the severe acute respiratory syndrome (SARS)-associated coronavirus harboring mutations that lower frameshift efficiency decreased infectivity by >4 orders of magnitude. Second, a series of frameshift-promoting mRNA pseudoknot mutants was employed to demonstrate that the frameshift signals of the SARS-associated coronavirus and mouse hepatitis virus have evolved to promote optimal frameshift efficiencies. Finally, we show that a previously described frameshift attenuator element does not actually affect frameshifting per se but rather serves to limit the fraction of ribosomes available for frameshifting. The findings of these analyses all support a "golden mean" model in which viruses use both programmed ribosomal frameshifting and translational attenuation to control the relative ratios of their encoded proteins.

  2. Differential Sensitivity of Bat Cells to Infection by Enveloped RNA Viruses: Coronaviruses, Paramyxoviruses, Filoviruses, and Influenza Viruses

    PubMed Central

    Hoffmann, Markus; Müller, Marcel Alexander; Drexler, Jan Felix; Glende, Jörg; Erdt, Meike; Gützkow, Tim; Losemann, Christoph; Binger, Tabea; Deng, Hongkui; Schwegmann-Weßels, Christel; Esser, Karl-Heinz; Drosten, Christian; Herrler, Georg

    2013-01-01

    Bats (Chiroptera) host major human pathogenic viruses including corona-, paramyxo, rhabdo- and filoviruses. We analyzed six different cell lines from either Yinpterochiroptera (including African flying foxes and a rhinolophid bat) or Yangochiroptera (genera Carollia and Tadarida) for susceptibility to infection by different enveloped RNA viruses. None of the cells were sensitive to infection by transmissible gastroenteritis virus (TGEV), a porcine coronavirus, or to infection mediated by the Spike (S) protein of SARS-coronavirus (SARS-CoV) incorporated into pseudotypes based on vesicular stomatitis virus (VSV). The resistance to infection was overcome if cells were transfected to express the respective cellular receptor, porcine aminopeptidase N for TGEV or angiotensin-converting enzyme 2 for SARS-CoV. VSV pseudotypes containing the S proteins of two bat SARS-related CoV (Bg08 and Rp3) were unable to infect any of the six tested bat cell lines. By contrast, viral pseudotypes containing the surface protein GP of Marburg virus from the family Filoviridae infected all six cell lines though at different efficiency. Notably, all cells were sensitive to infection by two paramyxoviruses (Sendai virus and bovine respiratory syncytial virus) and three influenza viruses from different subtypes. These results indicate that bat cells are more resistant to infection by coronaviruses than to infection by paramyxoviruses, filoviruses and influenza viruses. Furthermore, these results show a receptor-dependent restriction of the infection of bat cells by CoV. The implications for the isolation of coronaviruses from bats are discussed. PMID:24023659

  3. Achieving a Golden Mean: Mechanisms by Which Coronaviruses Ensure Synthesis of the Correct Stoichiometric Ratios of Viral Proteins▿

    PubMed Central

    Plant, Ewan P.; Rakauskaitė, Rasa; Taylor, Deborah R.; Dinman, Jonathan D.

    2010-01-01

    In retroviruses and the double-stranded RNA totiviruses, the efficiency of programmed −1 ribosomal frameshifting is critical for ensuring the proper ratios of upstream-encoded capsid proteins to downstream-encoded replicase enzymes. The genomic organizations of many other frameshifting viruses, including the coronaviruses, are very different, in that their upstream open reading frames encode nonstructural proteins, the frameshift-dependent downstream open reading frames encode enzymes involved in transcription and replication, and their structural proteins are encoded by subgenomic mRNAs. The biological significance of frameshifting efficiency and how the relative ratios of proteins encoded by the upstream and downstream open reading frames affect virus propagation has not been explored before. Here, three different strategies were employed to test the hypothesis that the −1 PRF signals of coronaviruses have evolved to produce the correct ratios of upstream- to downstream-encoded proteins. Specifically, infectious clones of the severe acute respiratory syndrome (SARS)-associated coronavirus harboring mutations that lower frameshift efficiency decreased infectivity by >4 orders of magnitude. Second, a series of frameshift-promoting mRNA pseudoknot mutants was employed to demonstrate that the frameshift signals of the SARS-associated coronavirus and mouse hepatitis virus have evolved to promote optimal frameshift efficiencies. Finally, we show that a previously described frameshift attenuator element does not actually affect frameshifting per se but rather serves to limit the fraction of ribosomes available for frameshifting. The findings of these analyses all support a “golden mean” model in which viruses use both programmed ribosomal frameshifting and translational attenuation to control the relative ratios of their encoded proteins. PMID:20164235

  4. A facile inhibitor screening of SARS coronavirus N protein using nanoparticle-based RNA oligonucleotide.

    PubMed

    Roh, Changhyun

    2012-01-01

    Hundreds of million people worldwide have been infected with severe acute respiratory syndrome (SARS), and the rate of global death from SARS has remarkably increased. Hence, the development of efficient drug treatments for the biological effects of SARS is highly needed. We have previously shown that quantum dots (QDs)-conjugated RNA oligonucleotide is sensitive to the specific recognition of the SARS-associated coronavirus (SARS-CoV) nucleocapsid (N) protein. In this study, we found that a designed biochip could analyze inhibitors of the SARS-CoV N protein using nanoparticle-based RNA oligonucleotide. Among the polyphenolic compounds examined, (-)-catechin gallate and (-)-gallocatechin gallate demonstrated a remarkable inhibition activity on SARS-CoV N protein. (-)-catechin gallate and (-)-gallocatechin gallate attenuated the binding affinity in a concentrated manner as evidenced by QDs-conjugated RNA oligonucleotide on a designed biochip. At a concentration of 0.05 μg mL(-1), (-)-catechin gallate and (-)-gallocatechin gallate showed more than 40% inhibition activity on a nanoparticle-based RNA oligonucleotide biochip system.

  5. Neotropical Bats from Costa Rica harbour Diverse Coronaviruses.

    PubMed

    Moreira-Soto, A; Taylor-Castillo, L; Vargas-Vargas, N; Rodríguez-Herrera, B; Jiménez, C; Corrales-Aguilar, E

    2015-11-01

    Bats are hosts of diverse coronaviruses (CoVs) known to potentially cross the host-species barrier. For analysing coronavirus diversity in a bat species-rich country, a total of 421 anal swabs/faecal samples from Costa Rican bats were screened for CoV RNA-dependent RNA polymerase (RdRp) gene sequences by a pancoronavirus PCR. Six families, 24 genera and 41 species of bats were analysed. The detection rate for CoV was 1%. Individuals (n = 4) from four different species of frugivorous (Artibeus jamaicensis, Carollia perspicillata and Carollia castanea) and nectivorous (Glossophaga soricina) bats were positive for coronavirus-derived nucleic acids. Analysis of 440 nt. RdRp sequences allocated all Costa Rican bat CoVs to the α-CoV group. Several CoVs sequences clustered near previously described CoVs from the same species of bat, but were phylogenetically distant from the human CoV sequences identified to date, suggesting no recent spillover events. The Glossophaga soricina CoV sequence is sufficiently dissimilar (26% homology to the closest known bat CoVs) to represent a unique coronavirus not clustering near other CoVs found in the same bat species so far, implying an even higher CoV diversity than previously suspected. © 2015 Blackwell Verlag GmbH.

  6. [Nosocomial infections due to human coronaviruses in the newborn].

    PubMed

    Gagneur, A; Legrand, M C; Picard, B; Baron, R; Talbot, P J; de Parscau, L; Sizun, J

    2002-01-01

    Human coronaviruses, with two known serogroups named 229-E and OC-43, are enveloped positive-stranded RNA viruses. The large RNA is surrounded by a nucleoprotein (protein N). The envelop contains 2 or 3 glycoproteins: spike protein (or protein S), matrix protein (or protein M) and a hemagglutinin (or protein HE). Their pathogen role remains unclear because their isolation is difficult. Reliable and rapid methods as immunofluorescence with monoclonal antibodies and reverse transcription-polymerase chain reaction allow new researches on epidemiology. Human coronaviruses can survive for as long as 6 days in suspension and 3 hours after drying on surfaces, suggesting that they could be a source of hospital-acquired infections. Two prospective studies conducted in a neonatal and paediatric intensive care unit demonstrated a significant association of coronavirus-positive nasopharyngal samples with respiratory illness in hospitalised preterm neonates. Positive samples from staff suggested either a patient-to-staff or a staff-to-patient transmission. No cross-infection were observed from community-acquired respiratory-syncitial virus or influenza-infected children to neonates. Universal precautions with hand washing and surface desinfection could be proposed to prevent coronavirus transmission.

  7. About Coronavirus

    MedlinePlus

    ... Coronaviruses Symptoms and Diagnosis Transmission Prevention and Treatment Human Coronavirus Types SARS-CoV MERS-CoV Resources and References About Coronaviruses Recommend on Facebook Tweet Share Compartir Symptoms and Diagnosis Lists illnesses ...

  8. Isolation and characterization of a novel Betacoronavirus subgroup A coronavirus, rabbit coronavirus HKU14, from domestic rabbits.

    PubMed

    Lau, Susanna K P; Woo, Patrick C Y; Yip, Cyril C Y; Fan, Rachel Y Y; Huang, Yi; Wang, Ming; Guo, Rongtong; Lam, Carol S F; Tsang, Alan K L; Lai, Kenneth K Y; Chan, Kwok-Hung; Che, Xiao-Yan; Zheng, Bo-Jian; Yuen, Kwok-Yung

    2012-05-01

    We describe the isolation and characterization of a novel Betacoronavirus subgroup A coronavirus, rabbit coronavirus HKU14 (RbCoV HKU14), from domestic rabbits. The virus was detected in 11 (8.1%) of 136 rabbit fecal samples by reverse transcriptase PCR (RT-PCR), with a viral load of up to 10(8) copies/ml. RbCoV HKU14 was able to replicate in HRT-18G and RK13 cells with cytopathic effects. Northern blotting confirmed the production of subgenomic mRNAs coding for the HE, S, NS5a, E, M, and N proteins. Subgenomic mRNA analysis revealed a transcription regulatory sequence, 5'-UCUAAAC-3'. Phylogenetic analysis showed that RbCoV HKU14 formed a distinct branch among Betacoronavirus subgroup A coronaviruses, being most closely related to but separate from the species Betacoronavirus 1. A comparison of the conserved replicase domains showed that RbCoV HKU14 possessed <90% amino acid identities to most members of Betacoronavirus 1 in ADP-ribose 1″-phosphatase (ADRP) and nidoviral uridylate-specific endoribonuclease (NendoU), indicating that RbCoV HKU14 should represent a separate species. RbCoV HKU14 also possessed genomic features distinct from those of other Betacoronavirus subgroup A coronaviruses, including a unique NS2a region with a variable number of small open reading frames (ORFs). Recombination analysis revealed possible recombination events during the evolution of RbCoV HKU14 and members of Betacoronavirus 1, which may have occurred during cross-species transmission. Molecular clock analysis using RNA-dependent RNA polymerase (RdRp) genes dated the most recent common ancestor of RbCoV HKU14 to around 2002, suggesting that this virus has emerged relatively recently. Antibody against RbCoV was detected in 20 (67%) of 30 rabbit sera tested by an N-protein-based Western blot assay, whereas neutralizing antibody was detected in 1 of these 20 rabbits.

  9. Flavivirus RNA Synthesis in vitro

    PubMed Central

    Padmanabhan, Radhakrishnan; Takhampunya, Ratree; Teramoto, Tadahisa; Choi, Kyung H.

    2015-01-01

    Summary Establishment of in vitro systems to study mechanisms of RNA synthesis for positive strand RNA viruses have been very useful in the past and have shed light on the composition of protein and RNA components, optimum conditions, the nature of the products formed, cis-acting RNA elements and trans-acting protein factors required for efficient synthesis. In this review, we summarize our current understanding regarding the requirements for flavivirus RNA synthesis in vitro. We describe details of reaction conditions, the specificity of template used by either the multi-component membrane-bound viral replicase complex or by purified, recombinant RNA-dependent RNA polymerase. We also discuss future perspectives to extend the boundaries of our knowledge. PMID:26272247

  10. Genomic and serological detection of bat coronavirus from bats in the Philippines.

    PubMed

    Tsuda, Shumpei; Watanabe, Shumpei; Masangkay, Joseph S; Mizutani, Tetsuya; Alviola, Phillip; Ueda, Naoya; Iha, Koichiro; Taniguchi, Satoshi; Fujii, Hikaru; Kato, Kentaro; Horimoto, Taisuke; Kyuwa, Shigeru; Yoshikawa, Yasuhiro; Akashi, Hiroomi

    2012-12-01

    Bat coronavirus (BtCoV) is assumed to be a progenitor of severe acute respiratory syndrome (SARS)-related coronaviruses. To explore the distribution of BtCoVs in the Philippines, we collected 179 bats and detected viral RNA from intestinal or fecal samples by RT-PCR. The overall prevalence of BtCoVs among bats was 29.6 %. Phylogenetic analysis of the partial RNA-dependent RNA polymerase gene suggested that one of the detected BtCoVs was a novel alphacoronavirus, while the others belonged to the genus Betacoronavirus. Western blotting revealed that 66.5 % of bat sera had antibodies to BtCoV. These surveys suggested the endemic presence of BtCoVs in the Philippines.

  11. Inhibition, Escape, and Attenuated Growth of Severe Acute Respiratory Syndrome Coronavirus Treated with Antisense Morpholino Oligomers†

    PubMed Central

    Neuman, Benjamin W.; Stein, David A.; Kroeker, Andrew D.; Churchill, Michael J.; Kim, Alice M.; Kuhn, Peter; Dawson, Philip; Moulton, Hong M.; Bestwick, Richard K.; Iversen, Patrick L.; Buchmeier, Michael J.

    2005-01-01

    The recently emerged severe acute respiratory syndrome coronavirus (SARS-CoV) is a potent pathogen of humans and is capable of rapid global spread. Peptide-conjugated antisense morpholino oligomers (P-PMO) were designed to bind by base pairing to specific sequences in the SARS-CoV (Tor2 strain) genome. The P-PMO were tested for their capacity to inhibit production of infectious virus as well as to probe the function of conserved viral RNA motifs and secondary structures. Several virus-targeted P-PMO and a random-sequence control P-PMO showed low inhibitory activity against SARS coronavirus. Certain other virus-targeted P-PMO reduced virus-induced cytopathology and cell-to-cell spread as a consequence of decreasing viral amplification. Active P-PMO were effective when administered at any time prior to peak viral synthesis and exerted sustained antiviral effects while present in culture medium. P-PMO showed low nonspecific inhibitory activity against translation of nontargeted RNA or growth of the arenavirus lymphocytic choriomeningitis virus. Two P-PMO targeting the viral transcription-regulatory sequence (TRS) region in the 5′ untranslated region were the most effective inhibitors tested. After several viral passages in the presence of a TRS-targeted P-PMO, partially drug-resistant SARS-CoV mutants arose which contained three contiguous base point mutations at the binding site of a TRS-targeted P-PMO. Those partially resistant viruses grew more slowly and formed smaller plaques than wild-type SARS-CoV. These results suggest PMO compounds have powerful therapeutic and investigative potential toward coronavirus infection. PMID:16014928

  12. Purified coronavirus Spike protein nanoparticles induce coronavirus neutralizing antibodies in mice

    PubMed Central

    Mu, Haiyan; Taylor, Justin K; Massare, Michael; Flyer, David C

    2014-01-01

    Development of vaccination strategies for emerging pathogens are particularly challenging because of the sudden nature of the emergence of these viruses and the long process needed for traditional vaccine development. Therefore, there is a need for development of a rapid method of vaccine development that can respond to emerging pathogens in a short time frame. The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003 and Middle East respiratory syndrome (MERS-CoV) in late 2012 demonstrate the importance of coronaviruses as emerging pathogens. The spike glycoproteins of coronaviruses reside on the surface of the virion and are responsible for virus entry. The spike glycoprotein is the major immunodominant antigen of coronaviruses and has proven to be an excellent target for vaccine designs that seek to block coronavirus entry and promote antibody targeting of infected cells. Vaccination strategies for coronaviruses have involved live attenuated virus, recombinant viruses, non-replicative virus-like particles expressing coronavirus proteins or DNA plasmids expressing coronavirus genes. None of these strategies has progressed to an approved human coronavirus vaccine in the ten years since SARS-CoV emerged. Here we describe a novel method for generating MERS-CoV and SARS-CoV full-length spike nanoparticles, which in combination with adjuvants are able to produce high titer antibodies in mice. PMID:24736006

  13. From SARS coronavirus to novel animal and human coronaviruses.

    PubMed

    To, Kelvin K W; Hung, Ivan F N; Chan, Jasper F W; Yuen, Kwok-Yung

    2013-08-01

    In 2003, severe acute respiratory syndrome coronavirus (SARS-CoV) caused one of the most devastating epidemics known to the developed world. There were two important lessons from this epidemic. Firstly, coronaviruses, in addition to influenza viruses, can cause severe and rapidly spreading human infections. Secondly, bats can serve as the origin and natural animal reservoir of deadly human viruses. Since then, researchers around the world, especially those in Asia where SARS-CoV was first identified, have turned their focus to find novel coronaviruses infecting humans, bats, and other animals. Two human coronaviruses, HCoV-HKU1 and HCoV-NL63, were identified shortly after the SARS-CoV epidemic as common causes of human respiratory tract infections. In 2012, a novel human coronavirus, now called Middle East respiratory syndrome coronavirus (MERS-CoV), has emerged in the Middle East to cause fatal human infections in three continents. MERS-CoV human infection is similar to SARS-CoV in having a high fatality rate and the ability to spread from person to person which resulted in secondary cases among close contacts including healthcare workers without travel history to the Middle East. Both viruses also have close relationships with bat coronaviruses. New cases of MERS-CoV infection in humans continue to occur with the origins of the virus still unknown in many cases. A multifaceted approach is necessary to control this evolving MERS-CoV outbreak. Source identification requires detailed epidemiological studies of the infected patients and enhanced surveillance of MERS-CoV or similar coronaviruses in humans and animals. Early diagnosis of infected patients and appropriate infection control measures will limit the spread in hospitals, while social distancing strategies may be necessary to control the outbreak in communities if it remained uncontrolled as in the SARS epidemic.

  14. A Kinome-Wide Small Interfering RNA Screen Identifies Proviral and Antiviral Host Factors in Severe Acute Respiratory Syndrome Coronavirus Replication, Including Double-Stranded RNA-Activated Protein Kinase and Early Secretory Pathway Proteins

    PubMed Central

    de Wilde, Adriaan H.; Wannee, Kazimier F.; Scholte, Florine E. M.; Goeman, Jelle J.; ten Dijke, Peter; Snijder, Eric J.

    2015-01-01

    ABSTRACT To identify host factors relevant for severe acute respiratory syndrome-coronavirus (SARS-CoV) replication, we performed a small interfering RNA (siRNA) library screen targeting the human kinome. Protein kinases are key regulators of many cellular functions, and the systematic knockdown of their expression should provide a broad perspective on factors and pathways promoting or antagonizing coronavirus replication. In addition to 40 proteins that promote SARS-CoV replication, our study identified 90 factors exhibiting an antiviral effect. Pathway analysis grouped subsets of these factors in specific cellular processes, including the innate immune response and the metabolism of complex lipids, which appear to play a role in SARS-CoV infection. Several factors were selected for in-depth validation in follow-up experiments. In cells depleted for the β2 subunit of the coatomer protein complex (COPB2), the strongest proviral hit, we observed reduced SARS-CoV protein expression and a >2-log reduction in virus yield. Knockdown of the COPB2-related proteins COPB1 and Golgi-specific brefeldin A-resistant guanine nucleotide exchange factor 1 (GBF1) also suggested that COPI-coated vesicles and/or the early secretory pathway are important for SARS-CoV replication. Depletion of the antiviral double-stranded RNA-activated protein kinase (PKR) enhanced virus replication in the primary screen, and validation experiments confirmed increased SARS-CoV protein expression and virus production upon PKR depletion. In addition, cyclin-dependent kinase 6 (CDK6) was identified as a novel antiviral host factor in SARS-CoV replication. The inventory of pro- and antiviral host factors and pathways described here substantiates and expands our understanding of SARS-CoV replication and may contribute to the identification of novel targets for antiviral therapy. IMPORTANCE Replication of all viruses, including SARS-CoV, depends on and is influenced by cellular pathways. Although

  15. Genomic Characterization of a Newly Discovered Coronavirus Associated with Acute Respiratory Distress Syndrome in Humans

    PubMed Central

    van Boheemen, Sander; de Graaf, Miranda; Lauber, Chris; Bestebroer, Theo M.; Raj, V. Stalin; Zaki, Ali Moh; Osterhaus, Albert D. M. E.; Haagmans, Bart L.; Gorbalenya, Alexander E.; Snijder, Eric J.; Fouchier, Ron A. M.

    2012-01-01

    ABSTRACT A novel human coronavirus (HCoV-EMC/2012) was isolated from a man with acute pneumonia and renal failure in June 2012. This report describes the complete genome sequence, genome organization, and expression strategy of HCoV-EMC/2012 and its relation with known coronaviruses. The genome contains 30,119 nucleotides and contains at least 10 predicted open reading frames, 9 of which are predicted to be expressed from a nested set of seven subgenomic mRNAs. Phylogenetic analysis of the replicase gene of coronaviruses with completely sequenced genomes showed that HCoV-EMC/2012 is most closely related to Tylonycteris bat coronavirus HKU4 (BtCoV-HKU4) and Pipistrellus bat coronavirus HKU5 (BtCoV-HKU5), which prototype two species in lineage C of the genus Betacoronavirus. In accordance with the guidelines of the International Committee on Taxonomy of Viruses, and in view of the 75% and 77% amino acid sequence identity in 7 conserved replicase domains with BtCoV-HKU4 and BtCoV-HKU5, respectively, we propose that HCoV-EMC/2012 prototypes a novel species in the genus Betacoronavirus. HCoV-EMC/2012 may be most closely related to a coronavirus detected in Pipistrellus pipistrellus in The Netherlands, but because only a short sequence from the most conserved part of the RNA-dependent RNA polymerase-encoding region of the genome was reported for this bat virus, its genetic distance from HCoV-EMC remains uncertain. HCoV-EMC/2012 is the sixth coronavirus known to infect humans and the first human virus within betacoronavirus lineage C. PMID:23170002

  16. RNA turnover and protein synthesis in fish cells.

    PubMed

    Smith, R W; Palmer, R M; Houlihan, D F

    2000-03-01

    Protein synthesis in fish has been previously correlated with RNA content. The present study investigates whether protein and RNA synthesis rates are similarly related. Protein and RNA synthesis rates were determined from 3H-phenylalanine and 3H-uridine incorporation, respectively, and expressed as % x day(-1) and half-lives, respectively. Three fibroblast cell lines were used: BF-2, RTP, CHSE 214, which are derived from the bluegill, rainbow trout and Chinook salmon, respectively. These cells contained similar RNA concentrations (approximately 175 microg RNA x mg(-1) cell protein). Therefore differences in protein synthesis rates, BF-2 (31.3 +/- 1.8)>RTP (25.1 +/- 1.7)>CHSE 214 (17.6 +/-1.1), were attributable to RNA translational efficiency. The most translationally efficient RNA (BF-2 cells), 1.8 mg protein synthesised x microg(-1) RNA x day(-1), corresponded to the lowest RNA half-life, 75.4 +/- 6.4 h. Translationally efficient RNA was also energetically efficient with BF-2 cells exploiting the least costly route of nucleotide supply (i.e. exogenous salvage) 3.5-6.0 times more than the least translationally efficient RNA (CHSE 214 cells). These data suggest that differential nucleotide supply, between intracellular synthesis and exogenous salvage, constitutes the area of pre-translational flexibility exploited to maintain RNA synthesis as a fixed energetic cost component of protein synthesis.

  17. Interaction of the Coronavirus Infectious Bronchitis Virus Membrane Protein with β-Actin and Its Implication in Virion Assembly and Budding

    PubMed Central

    Wang, Jibin; Fang, Shouguo; Xiao, Han; Chen, Bo; Tam, James P.; Liu, Ding Xiang

    2009-01-01

    Coronavirus M protein is an essential component of virion and plays pivotal roles in virion assembly, budding and maturation. The M protein is integrated into the viral envelope with three transmembrane domains flanked by a short amino-terminal ectodomain and a large carboxy-terminal endodomain. In this study, we showed co-purification of the M protein from coronavirus infectious bronchitis virus (IBV) with actin. To understand the cellular factors that may be involved in virion assembly, budding and maturation processes, IBV M was used as the bait in a yeast two-hybrid screen, resulting in the identification of β-actin as a potentially interacting partner. This interaction was subsequently confirmed by coimmunoprecipitation and immunofluorescence microscopy in mammalian cells, and mutation of amino acids A159 and K160 on the M protein abolished the interaction. Introduction of the A159-K160 mutation into an infectious IBV clone system blocks the infectivity of the clone, although viral RNA replication and subgenomic mRNA transcription were actively detected. Disruption of actin filaments with cell-permeable agent cytochalasin D at early stages of the infection cycle led to the detection of viral protein synthesis in infected cells but not release of virus particles to the cultured media. However, the same treatment at late stages of the infection cycle did not affect the release of virus particles to the media, suggesting that disruption of the actin filaments might block virion assembly and budding, but not release of the virus particles. This study reveals an essential function of actin in the replication cycle of coronavirus. PMID:19287488

  18. Regulation of Flavivirus RNA synthesis and replication

    PubMed Central

    Selisko, Barbara; Wang, Chunling; Harris, Eva; Canard, Bruno

    2014-01-01

    RNA synthesis and replication of the members of the Flavivirus genus (including dengue, West Nile and Japanese encephalitis viruses) is regulated by a wide variety of mechanisms and actors. These include the sequestration of the RNA-dependent RNA polymerase (RdRp) for functions other than RNA synthesis, regulatory interactions with other viral and host proteins within the replication complex (RC), and regulatory elements within the RNA genome itself. In this review, we discuss our current knowledge of the multiple levels at which Flavivirus RNA synthesis is controlled. We aim to bring together two active research fields: the structural and functional biology of individual proteins of the RC and the impressive wealth of knowledge acquired regarding the viral genomic RNA. PMID:25462437

  19. Coronaviruses in guano from Pteropus medius bats in Peradeniya, Sri Lanka.

    PubMed

    Kudagammana, H D W S; Thevanesam, V; Chu, D K W; Eriyagama, N B; Peiris, J S M; Noordeen, F

    2018-03-02

    Bats are a unique group of mammals well suited to be hosts for emerging viruses. With current rates of deforestation and urbanization, redistribution of bat habitats to urban and suburban areas may bring bats into closer contact with livestock and humans. Common flying fox, Pteropus medius (previously known as Pteropus giganteus), forms large communal roosts on treetops, often in close proximity to human habitation in Sri Lanka. This report describes the detection of coronavirus RNA in P. medius bat guano collected in Peradeniya, Sri Lanka. These viruses had >97% nucleotide identity with coronaviruses detected in Cynopterus sphinx, Scotophilus heathii and S. kuhlii bats in Thailand. Pteropus medius is widespread in Asia and appears to excrete group D coronaviruses, which are hitherto confined to bats; however, these findings may have public health implications in the future. © 2018 Blackwell Verlag GmbH.

  20. Cyclophilin B stimulates RNA synthesis by the HCV RNA dependent RNA polymerase.

    PubMed

    Heck, Julie A; Meng, Xiao; Frick, David N

    2009-04-01

    Cyclophilins are cellular peptidyl isomerases that have been implicated in regulating hepatitis C virus (HCV) replication. Cyclophilin B (CypB) is a target of cyclosporin A (CsA), an immunosuppressive drug recently shown to suppress HCV replication in cell culture. Watashi et al. recently demonstrated that CypB is important for efficient HCV replication, and proposed that it mediates the anti-HCV effects of CsA through an interaction with NS5B [Watashi K, Ishii N, Hijikata M, Inoue D, Murata T, Miyanari Y, et al. Cyclophilin B is a functional regulator of hepatitis C virus RNA polymerase. Mol Cell 2005;19:111-22]. We examined the effects of purified CypB proteins on the enzymatic activity of NS5B. Recombinant CypB purified from insect cells directly stimulated NS5B-catalyzed RNA synthesis. CypB increased RNA synthesis by NS5B derived from genotype 1a, 1b, and 2a HCV strains. Stimulation appears to arise from an increase in productive RNA binding. NS5B residue Pro540, a previously proposed target of CypB peptidyl-prolyl isomerase activity, is not required for stimulation of RNA synthesis.

  1. Cyclophilin B stimulates RNA synthesis by the HCV RNA dependent RNA polymerase

    PubMed Central

    Heck, Julie A.; Meng, Xiao; Frick, David N.

    2009-01-01

    Cyclophilins are cellular peptidyl isomerases that have been implicated in regulating hepatitis C virus (HCV) replication. Cyclophilin B (CypB) is a target of cyclosporin A (CsA), an immunosuppressive drug recently shown to suppress HCV replication in cell culture. Watashi et al. recently demonstrated that CypB is important for efficient HCV replication, and proposed that it mediates the anti-HCV effects of CsA through an interaction with NS5B (Mol. Cell 19:111). We examined the effects of purified CypB proteins on the enzymatic activity of NS5B. Recombinant CypB purified from insect cells directly stimulated NS5B-catalyzed RNA synthesis. CypB increased RNA synthesis by NS5B derived from genotype 1a, 1b, and 2a HCV strains. Stimulation appears to arise from an increase in productive RNA binding. NS5B residue Pro540, a previously proposed target of CypB peptidyl-prolyl isomerase activity, is not required for stimulation of RNA synthesis. PMID:19174155

  2. Accessory proteins of SARS-CoV and other coronaviruses.

    PubMed

    Liu, Ding Xiang; Fung, To Sing; Chong, Kelvin Kian-Long; Shukla, Aditi; Hilgenfeld, Rolf

    2014-09-01

    The huge RNA genome of SARS coronavirus comprises a number of open reading frames that code for a total of eight accessory proteins. Although none of these are essential for virus replication, some appear to have a role in virus pathogenesis. Notably, some SARS-CoV accessory proteins have been shown to modulate the interferon signaling pathways and the production of pro-inflammatory cytokines. The structural information on these proteins is also limited, with only two (p7a and p9b) having their structures determined by X-ray crystallography. This review makes an attempt to summarize the published knowledge on SARS-CoV accessory proteins, with an emphasis on their involvement in virus-host interaction. The accessory proteins of other coronaviruses are also briefly discussed. This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses" (see Introduction by Hilgenfeld and Peiris (2013)). Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The RNA synthesis machinery of negative-stranded RNA viruses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ortín, Juan, E-mail: jortin@cnb.csic.es; Martín-Benito, Jaime, E-mail: jmartinb@cnb.csic.es

    The group of Negative-Stranded RNA Viruses (NSVs) includes many human pathogens, like the influenza, measles, mumps, respiratory syncytial or Ebola viruses, which produce frequent epidemics of disease and occasional, high mortality outbreaks by transmission from animal reservoirs. The genome of NSVs consists of one to several single-stranded, negative-polarity RNA molecules that are always assembled into mega Dalton-sized complexes by association to many nucleoprotein monomers. These RNA-protein complexes or ribonucleoproteins function as templates for transcription and replication by action of the viral RNA polymerase and accessory proteins. Here we review our knowledge on these large RNA-synthesis machines, including the structure ofmore » their components, the interactions among them and their enzymatic activities, and we discuss models showing how they perform the virus transcription and replication programmes. - Highlights: • Overall organisation of NSV RNA synthesis machines. • Structure and function of the ribonucleoprotein components: Atomic structure of the RNA polymerase complex. • Commonalities and differences between segmented- and non-segmented NSVs. • Transcription versus replication programmes.« less

  4. Stability of bovine coronavirus on lettuce surfaces under household refrigeration conditions.

    PubMed

    Mullis, Lisa; Saif, Linda J; Zhang, Yongbin; Zhang, Xuming; Azevedo, Marli S P

    2012-05-01

    Fecal suspensions with an aerosol route of transmission were responsible for a cluster of severe acute respiratory syndrome (SARS) cases in 2003 in Hong Kong. Based on that event, the World Health Organization recommended that research be implemented to define modes of transmission of SARS coronavirus through sewage, feces, food and water. Environmental studies have shown that animal coronaviruses remain infectious in water and sewage for up to a year depending on the temperature and humidity. In this study, we examined coronavirus stability on lettuce surfaces. A cell culture adapted bovine coronavirus, diluted in growth media or in bovine fecal suspensions to simulate fecal contamination was used to spike romaine lettuce. qRT-PCR detected viral RNA copy number ranging from 6.6 × 10⁴ to 1.7 × 10⁶ throughout the experimental period of 30 days. Whereas infectious viruses were detected for at least 14 days, the amount of infectious virus varied, depending upon the diluent used for spiking the lettuce. UV and confocal microscopic observation indicated attachment of residual labeled virions to the lettuce surface after the elution procedure, suggesting that rates of inactivation or detection of the virus may be underestimated. Thus, it is possible that contaminated vegetables may be potential vehicles for coronavirus zoonotic transmission to humans. Published by Elsevier Ltd.

  5. Enhancement of RNA Synthesis, Protein Synthesis, and Abscission by Ethylene

    PubMed Central

    Abeles, F. B.; Holm, R. E.

    1966-01-01

    Ethylene stimulated RNA and protein synthesis in bean (Phaseolus vulgaris L. var. Red Kidney) abscission zone explants prior to abscission. The effect of ethylene on RNA synthesis and abscission was blocked by actinomycin D. Carbon dioxide, which inhibits the effect of ethylene on abscission, also inhibited the influence of ethylene on protein synthesis. An aging period appears to be essential before bean explants respond to ethylene. Stimulation of protein synthesis by ethylene occurred only in receptive or senescent explants. Treatment of juvenile explants with ethylene, which has no effect on abscission also has no effect on protein synthesis. Evidence in favor of a hormonal role for ethylene during abscission is discussed. PMID:16656405

  6. [Control of RNA biosynthesis in rat liver. Some features of RNA biosynthesis during prolonged protein synthesis inhibition].

    PubMed

    Todorov, I N; Shen, R A; Zheliabovskaia, S M; Galkin, A P

    1976-10-01

    A drastic inhibition of protein biosynthesis in rat liver in vivo by cycloheximide (CHI) (0.3 mg/100 g of body weight) first caused an increase of RNA synthesis (after 1 hour), which was then followed by its decrease. Partial gradual restoration of the protein synthesis level was shown to be accompanied by a repeated increase of RNA synthesis (12 hs) and its normalisation after 24 hs. The first maximum of RNA synthesis increase in the isolated nuclei system was AU-type RNA synthesis (sensitive to alpha-amanitine), the second one was due to GC-type RNA synthesis (resistant to this toxin). Purified chromatine template activity in the system with E. coli RNA polymerase (by 14%) an hour after CHI treatment, but 3 hrs later was decreased and subsequently restored (12 hrs after CHI injection). The changes of RNA biosynthesis induced by prolonged protein synthesis inhibition suggest the existence of continuous RNA synthesis control in nuclei. This control is realized by translation system using the feed back principle.

  7. Fluctuations and synchrony of RNA synthesis in nucleoli.

    PubMed

    Pliss, Artem; Kuzmin, Andrey N; Kachynski, Aliaksandr V; Baev, Alexander; Berezney, Ronald; Prasad, Paras N

    2015-06-01

    Ribosomal RNA (rRNA) sequences are synthesized at exceptionally high rates and, together with ribosomal proteins (r-proteins), are utilized as building blocks for the assembly of pre-ribosomal particles. Although it is widely acknowledged that tight regulation and coordination of rRNA and r-protein production are fundamentally important for the maintenance of cellular homeostasis, still little is known about the real-time kinetics of the ribosome component synthesis in individual cells. In this communication we introduce a label-free MicroRaman spectrometric approach for monitoring rRNA synthesis in live cultured cells. Remarkably high and rapid fluctuations of rRNA production rates were revealed by this technique. Strikingly, the changes in the rRNA output were synchronous for ribosomal genes located in separate nucleoli of the same cell. Our findings call for the development of new concepts to elucidate the coordination of ribosomal components production. In this regard, numerical modeling further demonstrated that the production of rRNA and r-proteins can be coordinated, regardless of the fluctuations in rRNA synthesis. Overall, our quantitative data reveal a spectacular interplay of inherently stochastic rates of RNA synthesis and the coordination of gene expression.

  8. Molecular Mapping of the RNA Cap 2′-O-Methyltransferase Activation Interface between Severe Acute Respiratory Syndrome Coronavirus nsp10 and nsp16*

    PubMed Central

    Lugari, Adrien; Betzi, Stephane; Decroly, Etienne; Bonnaud, Emmanuel; Hermant, Aurélie; Guillemot, Jean-Claude; Debarnot, Claire; Borg, Jean-Paul; Bouvet, Mickaël; Canard, Bruno; Morelli, Xavier; Lécine, Patrick

    2010-01-01

    Several protein-protein interactions within the SARS-CoV proteome have been identified, one of them being between non-structural proteins nsp10 and nsp16. In this work, we have mapped key residues on the nsp10 surface involved in this interaction. Alanine-scanning mutagenesis, bioinformatics, and molecular modeling were used to identify several “hot spots,” such as Val42, Met44, Ala71, Lys93, Gly94, and Tyr96, forming a continuous protein-protein surface of about 830 Å2, bearing very conserved amino acids among coronaviruses. Because nsp16 carries RNA cap 2′-O-methyltransferase (2′O-MTase) activity only in the presence of its interacting partner nsp10 (Bouvet, M., Debarnot, C., Imbert, I., Selisko, B., Snijder, E. J., Canard, B., and Decroly, E. (2010) PLoS Pathog. 6, e1000863), functional consequences of mutations on this surface were evaluated biochemically. Most changes that disrupted the nsp10-nsp16 interaction without structural perturbations were shown to abrogate stimulation of nsp16 RNA cap 2′O-MTase activity. More strikingly, the Y96A mutation abrogates stimulation of nsp16 2′O-MTase activity, whereas Y96F overstimulates it. Thus, the nsp10-nsp16 interface may represent an attractive target for antivirals against human and animal pathogenic coronaviruses. PMID:20699222

  9. Development and Evaluation of Novel Real-Time Reverse Transcription-PCR Assays with Locked Nucleic Acid Probes Targeting Leader Sequences of Human-Pathogenic Coronaviruses

    PubMed Central

    Chan, Jasper Fuk-Woo; Choi, Garnet Kwan-Yue; Tsang, Alan Ka-Lun; Tee, Kah-Meng; Lam, Ho-Yin; Yip, Cyril Chik-Yan; To, Kelvin Kai-Wang; Cheng, Vincent Chi-Chung; Yeung, Man-Lung; Lau, Susanna Kar-Pui; Woo, Patrick Chiu-Yat; Chan, Kwok-Hung; Tang, Bone Siu-Fai

    2015-01-01

    Based on findings in small RNA-sequencing (Seq) data analysis, we developed highly sensitive and specific real-time reverse transcription (RT)-PCR assays with locked nucleic acid probes targeting the abundantly expressed leader sequences of Middle East respiratory syndrome coronavirus (MERS-CoV) and other human coronaviruses. Analytical and clinical evaluations showed their noninferiority to a commercial multiplex PCR test for the detection of these coronaviruses. PMID:26019210

  10. Preparation of armored RNA as a control for multiplex real-time reverse transcription-PCR detection of influenza virus and severe acute respiratory syndrome coronavirus.

    PubMed

    Yu, Xin-Fen; Pan, Jing-Cao; Ye, Rong; Xiang, Hai-Qing; Kou, Yu; Huang, Zhi-Cheng

    2008-03-01

    The common respiratory viruses, including influenza A, influenza B, and newly emerging severe acute respiratory syndrome (SARS) viruses, may cause similar clinical symptoms. Therefore, differential diagnosis of these virus pathogens is frequently required for single clinical samples. In addition, there is an urgent need for noninfectious and stable RNA standards and controls for multivirus detection. In this study, reverse transcription-PCR (RT-PCR) targeting of the RNAs of influenza A and influenza B viruses and SARS coronavirus was performed, and the resulting products were spliced into a fragment which was packaged into armored RNA for use as a noninfectious, quantifiable synthetic substitute. Furthermore, in the present study we developed a multiplex real-time RT-PCR assay in which the armored RNA was used as an external positive control and the three RNA viruses could be detected simultaneously in a single reaction mix. The detection limit of the multiplex real-time PCR was 10 copies/microl of armored RNA.

  11. Hydrocortisone Stimulation of RNA Synthesis in Induction of Hepatic Enzymes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kenney, Francis T.; Wicks, Wesley D.; Greenman, David L.

    Increased synthesis of hepatic enzymes due to hydrocortisone is preceded by an increase in the rate of synthesis of nuclear RNA. Pulse-labeled RNA from liver nuclei was fractionated by a differential thermal phenol procedures, and the labeled RNA of each fraction was characterized by sucrose gradient centrifugation and base composition analysis. Hormone treatment increases the rate of synthesis of three types of RNA: (1) the nuclear precursor to ribosomal RNA, (2) a rapid turnover component with base composition similar to the tissue DNA, and (3) transfer RNA. Much of the total isotope incorporation into transfer RNA can be traced tomore » turnover of the terminal adenylate residue, but this type of labeling is insensitive to the hormone. The steroid also stimulates isotope incorporation into tissue precursor pools. The effect is abolished by actinomycin and thus is secondary to the hormonal stimulation of RNA synthesis. Growth hormone stimulates RNA synthesis in both intact and adrenalectomized rats, but induces the rapid turnover enzymes (tyrosine transaminase and tryptophan pyrrolase) only in the presence of functional adrenals. It therefore seems that glucocorticoids initiate both a generalized increase in synthesis of RNA and a selective induction of specific enzymes.« less

  12. Potent Inhibition of Feline Coronaviruses with Peptidyl Compounds Targeting Coronavirus 3C-like Protease

    PubMed Central

    Kim, Yunjeong; Mandadapu, Sivakoteswara Rao; Groutas, William C.; Chang, Kyeong-Ok

    2012-01-01

    Feline coronavirus infection is common among domestic and exotic felid species and usually associated with mild or asymptomatic enteritis; however, feline infectious peritonitis (FIP) is a fatal disease of cats that is caused by systemic infection with a feline infectious peritonitis virus (FIPV), a variant of feline enteric coronavirus (FECV). Currently, there is no specific treatment approved for FIP despite the importance of FIP as the leading infectious cause of death in young cats. During the replication process, coronavirus produces viral polyproteins that are processed into mature proteins by viral proteases, the main protease (3C-like [3CL] protease) and the papain-like protease. Since the cleavages of viral polyproteins are an essential step for virus replication, blockage of viral protease is an attractive target for therapeutic intervention. Previously, we reported the generation of broad-spectrum peptidyl inhibitors against viruses that possess a 3C or 3CL protease. In this study, we further evaluated the antiviral effects of the peptidyl inhibitors against feline coronaviruses, and investigated the interaction between our protease inhibitor and a cathepsin B inhibitor, an entry blocker, against feline coronaviruses in cell culture. Herein we report that our compounds behave as reversible, competitive inhibitors of 3CL protease, potently inhibited the replication of feline coronaviruses (EC50 in a nanomolar range) and, furthermore, the combination of cathepsin B and 3CL protease inhibitors led to a strong synergistic interaction against feline coronaviruses in cell culture systems. PMID:23219425

  13. Expression, post-translational modification and biochemical characterization of proteins encoded by subgenomic mRNA8 of the severe acute respiratory syndrome coronavirus.

    PubMed

    Le, Tra M; Wong, Hui H; Tay, Felicia P L; Fang, Shouguo; Keng, Choong-Tat; Tan, Yee J; Liu, Ding X

    2007-08-01

    The most striking difference between the subgenomic mRNA8 of severe acute respiratory syndrome coronavirus isolated from human and some animal species is the deletion of 29 nucleotides, resulting in splitting of a single ORF (ORF8) into two ORFs (ORF8a and ORF8b). ORF8a and ORF8b are predicted to encode two small proteins, 8a and 8b, and ORF8 a single protein, 8ab (a fusion form of 8a and 8b). To understand the functions of these proteins, we cloned cDNA fragments covering these ORFs into expression plasmids, and expressed the constructs in both in vitro and in vivo systems. Expression of a construct containing ORF8a and ORF8b generated only a single protein, 8a; no 8b protein expression was obtained. Expression of a construct containing ORF8 generated the 8ab fusion protein. Site-directed mutagenesis and enzymatic treatment revealed that protein 8ab is modified by N-linked glycosylation on the N81 residue and by ubiquitination. In the absence of the 8a region, protein 8b undergoes rapid degradation by proteasomes, and addition of proteasome inhibitors inhibits the degradation of protein 8b as well as the protein 8b-induced rapid degradation of the severe acute respiratory syndrome coronavirus E protein. Glycosylation could also stabilize protein 8ab. More interestingly, the two proteins could bind to monoubiquitin and polyubiquitin, suggesting the potential involvement of these proteins in the pathogenesis of severe acute respiratory syndrome coronavirus.

  14. Surveillance of Bat Coronaviruses in Kenya Identifies Relatives of Human Coronaviruses NL63 and 229E and Their Recombination History

    PubMed Central

    Tao, Ying; Shi, Mang; Chommanard, Christina; Queen, Krista; Zhang, Jing; Markotter, Wanda; Kuzmin, Ivan V.; Holmes, Edward C.

    2017-01-01

    ABSTRACT Bats harbor a large diversity of coronaviruses (CoVs), several of which are related to zoonotic pathogens that cause severe disease in humans. Our screening of bat samples collected in Kenya from 2007 to 2010 not only detected RNA from several novel CoVs but, more significantly, identified sequences that were closely related to human CoVs NL63 and 229E, suggesting that these two human viruses originate from bats. We also demonstrated that human CoV NL63 is a recombinant between NL63-like viruses circulating in Triaenops bats and 229E-like viruses circulating in Hipposideros bats, with the breakpoint located near 5′ and 3′ ends of the spike (S) protein gene. In addition, two further interspecies recombination events involving the S gene were identified, suggesting that this region may represent a recombination “hot spot” in CoV genomes. Finally, using a combination of phylogenetic and distance-based approaches, we showed that the genetic diversity of bat CoVs is primarily structured by host species and subsequently by geographic distances. IMPORTANCE Understanding the driving forces of cross-species virus transmission is central to understanding the nature of disease emergence. Previous studies have demonstrated that bats are the ultimate reservoir hosts for a number of coronaviruses (CoVs), including ancestors of severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and human CoV 229E (HCoV-229E). However, the evolutionary pathways of bat CoVs remain elusive. We provide evidence for natural recombination between distantly related African bat coronaviruses associated with Triaenops afer and Hipposideros sp. bats that resulted in a NL63-like virus, an ancestor of the human pathogen HCoV-NL63. These results suggest that interspecies recombination may play an important role in CoV evolution and the emergence of novel CoVs with zoonotic potential. PMID:28077633

  15. Catalysis and prebiotic RNA synthesis

    NASA Technical Reports Server (NTRS)

    Ferris, James P.

    1993-01-01

    The essential role of catalysis for the origins of life is discussed. The status of the prebiotic synthesis of 2',5'- and 3'5'-linked oligomers of RNA is reviewed. Examples of the role of metal ion and mineral catalysis in RNA oligomer formation are discussed.

  16. Discovery of Seven Novel Mammalian and Avian Coronaviruses in the Genus Deltacoronavirus Supports Bat Coronaviruses as the Gene Source of Alphacoronavirus and Betacoronavirus and Avian Coronaviruses as the Gene Source of Gammacoronavirus and Deltacoronavirus

    PubMed Central

    Woo, Patrick C. Y.; Lau, Susanna K. P.; Lam, Carol S. F.; Lau, Candy C. Y.; Tsang, Alan K. L.; Lau, John H. N.; Bai, Ru; Teng, Jade L. L.; Tsang, Chris C. C.; Wang, Ming; Zheng, Bo-Jian; Chan, Kwok-Hung

    2012-01-01

    Recently, we reported the discovery of three novel coronaviruses, bulbul coronavirus HKU11, thrush coronavirus HKU12, and munia coronavirus HKU13, which were identified as representatives of a novel genus, Deltacoronavirus, in the subfamily Coronavirinae. In this territory-wide molecular epidemiology study involving 3,137 mammals and 3,298 birds, we discovered seven additional novel deltacoronaviruses in pigs and birds, which we named porcine coronavirus HKU15, white-eye coronavirus HKU16, sparrow coronavirus HKU17, magpie robin coronavirus HKU18, night heron coronavirus HKU19, wigeon coronavirus HKU20, and common moorhen coronavirus HKU21. Complete genome sequencing and comparative genome analysis showed that the avian and mammalian deltacoronaviruses have similar genome characteristics and structures. They all have relatively small genomes (25.421 to 26.674 kb), the smallest among all coronaviruses. They all have a single papain-like protease domain in the nsp3 gene; an accessory gene, NS6 open reading frame (ORF), located between the M and N genes; and a variable number of accessory genes (up to four) downstream of the N gene. Moreover, they all have the same putative transcription regulatory sequence of ACACCA. Molecular clock analysis showed that the most recent common ancestor of all coronaviruses was estimated at approximately 8100 BC, and those of Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus were at approximately 2400 BC, 3300 BC, 2800 BC, and 3000 BC, respectively. From our studies, it appears that bats and birds, the warm blooded flying vertebrates, are ideal hosts for the coronavirus gene source, bats for Alphacoronavirus and Betacoronavirus and birds for Gammacoronavirus and Deltacoronavirus, to fuel coronavirus evolution and dissemination. PMID:22278237

  17. Discovery of seven novel Mammalian and avian coronaviruses in the genus deltacoronavirus supports bat coronaviruses as the gene source of alphacoronavirus and betacoronavirus and avian coronaviruses as the gene source of gammacoronavirus and deltacoronavirus.

    PubMed

    Woo, Patrick C Y; Lau, Susanna K P; Lam, Carol S F; Lau, Candy C Y; Tsang, Alan K L; Lau, John H N; Bai, Ru; Teng, Jade L L; Tsang, Chris C C; Wang, Ming; Zheng, Bo-Jian; Chan, Kwok-Hung; Yuen, Kwok-Yung

    2012-04-01

    Recently, we reported the discovery of three novel coronaviruses, bulbul coronavirus HKU11, thrush coronavirus HKU12, and munia coronavirus HKU13, which were identified as representatives of a novel genus, Deltacoronavirus, in the subfamily Coronavirinae. In this territory-wide molecular epidemiology study involving 3,137 mammals and 3,298 birds, we discovered seven additional novel deltacoronaviruses in pigs and birds, which we named porcine coronavirus HKU15, white-eye coronavirus HKU16, sparrow coronavirus HKU17, magpie robin coronavirus HKU18, night heron coronavirus HKU19, wigeon coronavirus HKU20, and common moorhen coronavirus HKU21. Complete genome sequencing and comparative genome analysis showed that the avian and mammalian deltacoronaviruses have similar genome characteristics and structures. They all have relatively small genomes (25.421 to 26.674 kb), the smallest among all coronaviruses. They all have a single papain-like protease domain in the nsp3 gene; an accessory gene, NS6 open reading frame (ORF), located between the M and N genes; and a variable number of accessory genes (up to four) downstream of the N gene. Moreover, they all have the same putative transcription regulatory sequence of ACACCA. Molecular clock analysis showed that the most recent common ancestor of all coronaviruses was estimated at approximately 8100 BC, and those of Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus were at approximately 2400 BC, 3300 BC, 2800 BC, and 3000 BC, respectively. From our studies, it appears that bats and birds, the warm blooded flying vertebrates, are ideal hosts for the coronavirus gene source, bats for Alphacoronavirus and Betacoronavirus and birds for Gammacoronavirus and Deltacoronavirus, to fuel coronavirus evolution and dissemination.

  18. The SARS coronavirus nucleocapsid protein--forms and functions.

    PubMed

    Chang, Chung-ke; Hou, Ming-Hon; Chang, Chi-Fon; Hsiao, Chwan-Deng; Huang, Tai-huang

    2014-03-01

    The nucleocapsid phosphoprotein of the severe acute respiratory syndrome coronavirus (SARS-CoV N protein) packages the viral genome into a helical ribonucleocapsid (RNP) and plays a fundamental role during viral self-assembly. It is a protein with multifarious activities. In this article we will review our current understanding of the N protein structure and its interaction with nucleic acid. Highlights of the progresses include uncovering the modular organization, determining the structures of the structural domains, realizing the roles of protein disorder in protein-protein and protein-nucleic acid interactions, and visualizing the ribonucleoprotein (RNP) structure inside the virions. It was also demonstrated that N-protein binds to nucleic acid at multiple sites with a coupled-allostery manner. We propose a SARS-CoV RNP model that conforms to existing data and bears resemblance to the existing RNP structures of RNA viruses. The model highlights the critical role of modular organization and intrinsic disorder of the N protein in the formation and functions of the dynamic RNP capsid in RNA viruses. This paper forms part of a symposium in Antiviral Research on "From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses." Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Development of Animal Models Against Emerging Coronaviruses: From SARS to MERS coronavirus

    PubMed Central

    Sutton, Troy C; Subbarao, Kanta

    2016-01-01

    Two novel coronaviruses have emerged to cause severe disease in humans. While bats may be the primary reservoir for both viruses, SARS coronavirus (SARS-CoV) likely crossed into humans from civets in China, and MERS coronavirus (MERS-CoV) has been transmitted from camels in the Middle East. Unlike SARS-CoV that resolved within a year, continued introductions of MERS-CoV present an on-going public health threat. Animal models are needed to evaluate countermeasures against emerging viruses. With SARS-CoV, several animal species were permissive to infection. In contrast, most laboratory animals are refractory or only semi-permissive to infection with MERS-CoV. This host-range restriction is largely determined by sequence heterogeneity in the MERS-CoV receptor. We describe animal models developed to study coronaviruses, with a focus on host-range restriction at the level of the viral receptor and discuss approaches to consider in developing a model to evaluate countermeasures against MERS-CoV. PMID:25791336

  20. Structure of the C-terminal domain of nsp4 from feline coronavirus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Manolaridis, Ioannis; Wojdyla, Justyna A.; Panjikar, Santosh

    2009-08-01

    The structure of the cytosolic C-terminal domain of nonstructural protein 4 from feline coronavirus has been determined and analyzed. Coronaviruses are a family of positive-stranded RNA viruses that includes important pathogens of humans and other animals. The large coronavirus genome (26–31 kb) encodes 15–16 nonstructural proteins (nsps) that are derived from two replicase polyproteins by autoproteolytic processing. The nsps assemble into the viral replication–transcription complex and nsp3, nsp4 and nsp6 are believed to anchor this enzyme complex to modified intracellular membranes. The largest part of the coronavirus nsp4 subunit is hydrophobic and is predicted to be embedded in the membranes.more » In this report, a conserved C-terminal domain (∼100 amino-acid residues) has been delineated that is predicted to face the cytoplasm and has been isolated as a soluble domain using library-based construct screening. A prototypical crystal structure at 2.8 Å resolution was obtained using nsp4 from feline coronavirus. Unmodified and SeMet-substituted proteins were crystallized under similar conditions, resulting in tetragonal crystals that belonged to space group P4{sub 3}. The phase problem was initially solved by single isomorphous replacement with anomalous scattering (SIRAS), followed by molecular replacement using a SIRAS-derived composite model. The structure consists of a single domain with a predominantly α-helical content displaying a unique fold that could be engaged in protein–protein interactions.« less

  1. RNA Synthesis by in Vitro Selected Ribozymes for Recreating an RNA World

    PubMed Central

    Martin, Lyssa L.; Unrau, Peter J.; Müller, Ulrich F.

    2015-01-01

    The RNA world hypothesis states that during an early stage of life, RNA molecules functioned as genome and as the only genome-encoded catalyst. This hypothesis is supported by several lines of evidence, one of which is the in vitro selection of catalytic RNAs (ribozymes) in the laboratory for a wide range of reactions that might have been used by RNA world organisms. This review focuses on three types of ribozymes that could have been involved in the synthesis of RNA, the core activity in the self-replication of RNA world organisms. These ribozyme classes catalyze nucleoside synthesis, triphosphorylation, and the polymerization of nucleoside triphosphates. The strengths and weaknesses regarding each ribozyme’s possible function in a self-replicating RNA network are described, together with the obstacles that need to be overcome before an RNA world organism can be generated in the laboratory. PMID:25610978

  2. Montmorillonite Clay-Catalyzed Synthesis of RNA Oligomers

    NASA Astrophysics Data System (ADS)

    Ferris, J. P.; Miyakawa, S.; Huang, W.; Joshi, P.

    2005-12-01

    It is proposed that catalysis had a central role in the origins of life. This will be illustrated using the montmorillonite clay-catalyzed synthesis of oligomers of RNA from activated monomers, (Ferris and Ertem, 1993) a possible step in the origin of the RNA world (Ferris, 2005). Structural analysis of oligomers formed in the reaction of the activated monomer of 5'-AMP with that of 5'-CMP demonstrated that the oligomers formed were not produced by random synthesis but rather the sequences observed were directed by the montmorillonite catalyst (Miyakawa and Ferris, 2003). RNA oligomers containing up to 40 mers have been synthesized in reactions performed in water at 25 oC in the presence of montmorillonite (Huang and Ferris, 2003). Analysis of the structure elements in these oligomers from the 7 to 39 mers showed that they did not vary. Reaction of D, L-mixtures of the activated monomers of A and U resulted in the formation of greater amounts of the homochiral amounts of dimers and trimers of A than would be expected if there was no selectivity in the reaction. A limited number of the dimers and trimers of U were also formed but here the selectivity was for the formation of an excess of heterochiral products (Joshi et al., 2000). A postulate that explains why homochiral trimers of U are not formed and the significance of catalysis in prebiotic synthesis will be discussed. Ferris, J.P. (2005) Origins of life, molecular basis of. In R.A. Meyers, Ed. Encyclopedia of Molecular Cell Biology and Molecular Medicine, 10. Wiley-VCH Verlag, Weinheim, Germany. Ferris, J.P., and Ertem, G. (1993) Montmorillonite catalysis of RNA oligomer formation in aqueous solution. A model for the prebiotic formation of RNA. J. Am. Chem. Soc., 115, 12270-12275. Huang, W., and Ferris, J.P. (2003) Synthesis of 35-40 mers of RNA oligomers from unblocked monomers. A simple approach to the RNA world. Chem. Commun., 1458-1459. Joshi, P.C., Pitsch, S., and Ferris, J.P. (2000) Homochiral selection

  3. Development of animal models against emerging coronaviruses: From SARS to MERS coronavirus.

    PubMed

    Sutton, Troy C; Subbarao, Kanta

    2015-05-01

    Two novel coronaviruses have emerged to cause severe disease in humans. While bats may be the primary reservoir for both viruses, SARS coronavirus (SARS-CoV) likely crossed into humans from civets in China, and MERS coronavirus (MERS-CoV) has been transmitted from camels in the Middle East. Unlike SARS-CoV that resolved within a year, continued introductions of MERS-CoV present an on-going public health threat. Animal models are needed to evaluate countermeasures against emerging viruses. With SARS-CoV, several animal species were permissive to infection. In contrast, most laboratory animals are refractory or only semi-permissive to infection with MERS-CoV. This host-range restriction is largely determined by sequence heterogeneity in the MERS-CoV receptor. We describe animal models developed to study coronaviruses, with a focus on host-range restriction at the level of the viral receptor and discuss approaches to consider in developing a model to evaluate countermeasures against MERS-CoV. Copyright © 2015. Published by Elsevier Inc.

  4. [Molecular cloning and expression of the severe acute respiratory syndrome-associated coronavirus nucleocapsid protein and its clinical application].

    PubMed

    Lu, Jian; Zhou, Bai-ping; Zhou, Yu-sen; Jiang, Xiao-ling; Wen, Li-xia; Le, Xiao-hua; Li, Bing; Xu, Liu-mei; Li, Li-xiong

    2005-03-01

    To clone and express nucleocapsid (N) protein of the severe acute respiratory syndrome (SARS)-associated coronavirus, and to evaluate its antigenicity and application value in the development of serological diagnostic test for SARS. SARS-associated coronavirus N protein gene was amplified from its genomic RNA by reverse transcript nested polymerase chain reaction (RT-nested-PCR) and cloned into pBAD/Thio-TOPO prokaryotic expression vector. The recombinant N fusion protein was expressed and purified, and its antigenicity and specificity was analyzed by Western Blot, to establish the recombinant N protein-based ELISA for detection of IgG antibodies to SARS-associated coronavirus, and SARS-associated coronavirus lysates-based ELISA was compared parallelly. The recombinant expression vector produced high level of the N fusion protein after induction, and that protein was purified successfully by affinity chromatography and displayed higher antigenicity and specificity as compared with whole virus lysates. The recombinant SARS-associated coronavirus N protein possessed better antigenicity and specificity and could be employed to establish a new, sensitive, and specific ELISA for SARS diagnosis.

  5. Ribozyme-catalysed RNA synthesis using triplet building blocks.

    PubMed

    Attwater, James; Raguram, Aditya; Morgunov, Alexey S; Gianni, Edoardo; Holliger, Philipp

    2018-05-15

    RNA-catalyzed RNA replication is widely believed to have supported a primordial biology. However, RNA catalysis is dependent upon RNA folding, and this yields structures that can block replication of such RNAs. To address this apparent paradox we have re-examined the building blocks used for RNA replication. We report RNA-catalysed RNA synthesis on structured templates when using trinucleotide triphosphates (triplets) as substrates, catalysed by a general and accurate triplet polymerase ribozyme that emerged from in vitro evolution as a mutualistic RNA heterodimer. The triplets cooperatively invaded and unraveled even highly stable RNA secondary structures, and support non-canonical primer-free and bidirectional modes of RNA synthesis and replication. Triplet substrates thus resolve a central incongruity of RNA replication, and here allow the ribozyme to synthesise its own catalytic subunit '+' and '-' strands in segments and assemble them into a new active ribozyme. © 2018, Attwater et al.

  6. Reversal of the Progression of Fatal Coronavirus Infection in Cats by a Broad-Spectrum Coronavirus Protease Inhibitor

    PubMed Central

    Kim, Yunjeong; Liu, Hongwei; Galasiti Kankanamalage, Anushka C.; Weerasekara, Sahani; Hua, Duy H.; Groutas, William C.; Chang, Kyeong-Ok; Pedersen, Niels C.

    2016-01-01

    Coronaviruses infect animals and humans causing a wide range of diseases. The diversity of coronaviruses in many mammalian species is contributed by relatively high mutation and recombination rates during replication. This dynamic nature of coronaviruses may facilitate cross-species transmission and shifts in tissue or cell tropism in a host, resulting in substantial change in virulence. Feline enteric coronavirus (FECV) causes inapparent or mild enteritis in cats, but a highly fatal disease, called feline infectious peritonitis (FIP), can arise through mutation of FECV to FIP virus (FIPV). The pathogenesis of FIP is intimately associated with immune responses and involves depletion of T cells, features shared by some other coronaviruses like Severe Acute Respiratory Syndrome Coronavirus. The increasing risks of highly virulent coronavirus infections in humans or animals call for effective antiviral drugs, but no such measures are yet available. Previously, we have reported the inhibitors that target 3C-like protease (3CLpro) with broad-spectrum activity against important human and animal coronaviruses. Here, we evaluated the therapeutic efficacy of our 3CLpro inhibitor in laboratory cats with FIP. Experimental FIP is 100% fatal once certain clinical and laboratory signs become apparent. We found that antiviral treatment led to full recovery of cats when treatment was started at a stage of disease that would be otherwise fatal if left untreated. Antiviral treatment was associated with a rapid improvement in fever, ascites, lymphopenia and gross signs of illness and cats returned to normal health within 20 days or less of treatment. Significant reduction in viral titers was also observed in cats. These results indicate that continuous virus replication is required for progression of immune-mediated inflammatory disease of FIP. These findings may provide important insights into devising therapeutic strategies and selection of antiviral compounds for further

  7. Preparation of His-tagged armored RNA phage particles as a control for real-time reverse transcription-PCR detection of severe acute respiratory syndrome coronavirus.

    PubMed

    Cheng, Yangjian; Niu, Jianjun; Zhang, Yongyou; Huang, Jianwei; Li, Qingge

    2006-10-01

    Armored RNA has been increasingly used as both an external and internal positive control in nucleic acid-based assays for RNA virus. In order to facilitate armored RNA purification, a His6 tag was introduced into the loop region of the MS2 coat protein, which allows the exposure of multiple His tags on the surface during armored RNA assembly. The His-tagged armored RNA particles were purified to homogeneity and verified to be free of DNA contamination in a single run of affinity chromatography. A fragment of severe acute respiratory syndrome coronavirus (SARS-CoV) genome targeted for SARS-CoV detection was chosen for an external positive control preparation. A plant-specific gene sequence was chosen for a universal noncompetitive internal positive control preparation. Both controls were purified by Co2+ affinity chromatography and were included in a real-time reverse transcription-PCR assay for SARS-CoV. The noncompetitive internal positive control can be added to clinical samples before RNA extraction and enables the identification of potential inhibitive effects without interfering with target amplification. The external control could be used for the quantification of viral loads in clinical samples.

  8. Anti-SARS coronavirus agents: a patent review (2008 - present).

    PubMed

    Kumar, Vathan; Jung, Young-Sik; Liang, Po-Huang

    2013-10-01

    A novel coronavirus (CoV), unlike previous typical human coronaviruses (HCoVs), was identified as causative agent for severe acute respiratory syndrome (SARS). SARS first surfaced as a pandemic in late 2002 and originated in southern China. SARS-CoV rapidly spread to > 30 countries by 2003, infecting nearly 8,000 people and causing around 800 fatalities. After 10 years of silence, a 2012 report alarmed researchers about the emergence of a new strain of CoV causing SARS-like disease. To combat SARS, scientists applied for patents on various therapeutic agents, including small-molecule inhibitors targeting the essential proteases, helicase and other proteins of the virus, natural products, approved drugs, molecules binding to the virus, neutralizing antibodies, vaccines, anti-sense RNA, siRNA and ribozyme against SARS-CoV. In this article, the patents published from 2008 to the present for the new therapeutics that could potentially be used in the prophylaxis and treatment of SARS are reviewed. The therapeutic interventions or prophylaxis discussed in this review seems to offer promising solutions to tackle SARS. Rather than being complacent about the results, we should envisage how to transform them into drug candidates that may be useful in combating SARS and related viral infections in the future.

  9. Genome-Wide Screen Reveals Valosin-Containing Protein Requirement for Coronavirus Exit from Endosomes

    PubMed Central

    Wong, Hui Hui; Kumar, Pankaj; Tay, Felicia Pei Ling; Moreau, Dimitri

    2015-01-01

    ABSTRACT Coronaviruses are RNA viruses with a large zoonotic reservoir and propensity for host switching, representing a real threat for public health, as evidenced by severe acute respiratory syndrome (SARS) and the emerging Middle East respiratory syndrome (MERS). Cellular factors required for their replication are poorly understood. Using genome-wide small interfering RNA (siRNA) screening, we identified 83 novel genes supporting infectious bronchitis virus (IBV) replication in human cells. Thirty of these hits can be placed in a network of interactions with viral proteins and are involved in RNA splicing, membrane trafficking, and ubiquitin conjugation. In addition, our screen reveals an unexpected role for valosin-containing protein (VCP/p97) in early steps of infection. Loss of VCP inhibits a previously uncharacterized degradation of the nucleocapsid N protein. This inhibition derives from virus accumulation in early endosomes, suggesting a role for VCP in the maturation of virus-loaded endosomes. The several host factors identified in this study may provide avenues for targeted therapeutics. IMPORTANCE Coronaviruses are RNA viruses representing a real threat for public health, as evidenced by SARS and the emerging MERS. However, cellular factors required for their replication are poorly understood. Using genome-wide siRNA screening, we identified novel genes supporting infectious bronchitis virus (IBV) replication in human cells. The several host factors identified in this study may provide directions for future research on targeted therapeutics. PMID:26311884

  10. Reverse Transcription Recombinase Polymerase Amplification Assay for the Detection of Middle East Respiratory Syndrome Coronavirus

    PubMed Central

    Abd El Wahed, Ahmed; Patel, Pranav; Heidenreich, Doris; Hufert, Frank T.; Weidmann, Manfred

    2013-01-01

    The emergence of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in the eastern Mediterranean and imported cases to Europe has alerted public health authorities. Currently, detection of MERS-CoV in patient samples is done by real-time RT-PCR. Samples collected from suspected cases are sent to highly-equipped centralized laboratories for screening. A rapid point-of-care test is needed to allow more widespread mobile detection of the virus directly from patient material. In this study, we describe the development of a reverse transcription isothermal Recombinase Polymerase Amplification (RT-RPA) assay for the identification of MERS-CoV. A partial nucleocapsid gene RNA molecular standard of MERS-coronavirus was used to determine the assay sensitivity. The isothermal (42°C) MERS-CoV RT-RPA was as sensitive as real-time RT-PCR (10 RNA molecules), rapid (3-7 minutes) and mobile (using tubescanner weighing 1kg). The MERS-CoV RT-RPA showed cross-detection neither of any of the RNAs of several coronaviruses and respiratory viruses affecting humans nor of the human genome. The developed isothermal real-time RT-RPA is ideal for rapid mobile molecular MERS-CoV monitoring in acute patients and may also facilitate the search for the animal reservoir of MERS-CoV. PMID:24459611

  11. Alisporivir inhibits MERS- and SARS-coronavirus replication in cell culture, but not SARS-coronavirus infection in a mouse model.

    PubMed

    de Wilde, Adriaan H; Falzarano, Darryl; Zevenhoven-Dobbe, Jessika C; Beugeling, Corrine; Fett, Craig; Martellaro, Cynthia; Posthuma, Clara C; Feldmann, Heinz; Perlman, Stanley; Snijder, Eric J

    2017-01-15

    Currently, there is no registered treatment for infections with emerging zoonotic coronaviruses like SARS- and MERS-coronavirus. We here report that in cultured cells low-micromolar concentrations of alisporivir, a non-immunosuppressive cyclosporin A-analog, inhibit the replication of four different coronaviruses, including MERS- and SARS-coronavirus. Ribavirin was found to further potentiate the antiviral effect of alisporivir in these cell culture-based infection models, but this combination treatment was unable to improve the outcome of SARS-CoV infection in a mouse model. Nevertheless, our data provide a basis to further explore the potential of Cyp inhibitors as host-directed, broad-spectrum inhibitors of coronavirus replication. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  12. THE ACTION OF α-AMANITIN ON RNA SYNTHESIS IN CHINESE HAMSTER OVARY CELLS

    PubMed Central

    Kedinger, Claude; Simard, Rene

    1974-01-01

    α-Amanitin acts in vitro as a selective inhibitor of the nucleoplasmic form B RNA polymerases. Treatment of Chinese hamster ovary (CHO) cells with this drug leads principally to a severe fragmentation of the nucleoli. While the ultrastructural lesions induced by α-amanitin in CHO cells and in rat or mouse liver are quite similar, the results diverge concerning the effect on RNA synthesis. It has been shown that in rat or mouse liver α-amanitin blocks both extranucleolar and nucleolar RNA synthesis. Our autoradiographic and biochemical evidence indicates that in CHO cells high molecular weight extranucleolar RNA synthesis (HnRNA) is blocked by the α-amanitin treatment, whereas nucleolar RNA (preribosomal RNA) synthesis remains unaffected even several hours after the inhibition of extranucleolar RNA synthesis. Furthermore, the processing of this RNA as well as its transport to the cytoplasm seem only slightly affected by the treatment. Finally, under these conditions, the synthesis of the low molecular RNA species (4–5S) still occurs, though less actively. The results are interpreted as evidence for a selective impairment of HnRNA synthesis by α-amanitin in CHO cells. PMID:4474178

  13. Interferon-Beta 1a and SARS Coronavirus Replication

    DTIC Science & Technology

    2004-02-01

    A global outbreak of severe acute respiratory syn- drome ( SARS ) caused by a novel coronavirus began in March 2003. The rapid emergence of SARS and...emerging infectious disease. The etiologic agent was identified as a coronavirus ( SARS -CoV) that is not closely related to any of the previously...some coronaviruses , including avian infectious bronchitis virus, murine hepati- tis virus, and human coronavirus 229E, are susceptible to type I

  14. Analyses of Coronavirus Assembly Interactions with Interspecies Membrane and Nucleocapsid Protein Chimeras

    PubMed Central

    Kuo, Lili; Hurst-Hess, Kelley R.; Koetzner, Cheri A.

    2016-01-01

    ABSTRACT The coronavirus membrane (M) protein is the central actor in virion morphogenesis. M organizes the components of the viral membrane, and interactions of M with itself and with the nucleocapsid (N) protein drive virus assembly and budding. In order to further define M-M and M-N interactions, we constructed mutants of the model coronavirus mouse hepatitis virus (MHV) in which all or part of the M protein was replaced by its phylogenetically divergent counterpart from severe acute respiratory syndrome coronavirus (SARS-CoV). We were able to obtain viable chimeras containing the entire SARS-CoV M protein as well as mutants with intramolecular substitutions that partitioned M protein at the boundaries between the ectodomain, transmembrane domains, or endodomain. Our results show that the carboxy-terminal domain of N protein, N3, is necessary and sufficient for interaction with M protein. However, despite some previous genetic and biochemical evidence that mapped interactions with N to the carboxy terminus of M, it was not possible to define a short linear region of M protein sufficient for assembly with N. Thus, interactions with N protein likely involve multiple linearly discontiguous regions of the M endodomain. The SARS-CoV M chimera exhibited a conditional growth defect that was partially suppressed by mutations in the envelope (E) protein. Moreover, virions of the M chimera were markedly deficient in spike (S) protein incorporation. These findings suggest that the interactions of M protein with both E and S protein are more complex than previously thought. IMPORTANCE The assembly of coronavirus virions entails concerted interactions among the viral structural proteins and the RNA genome. One strategy to study this process is through construction of interspecies chimeras that preserve or disrupt particular inter- or intramolecular associations. In this work, we replaced the membrane (M) protein of the model coronavirus mouse hepatitis virus with its

  15. Feline and Canine Coronaviruses: Common Genetic and Pathobiological Features

    PubMed Central

    Le Poder, Sophie

    2011-01-01

    A new human coronavirus responsible for severe acute respiratory syndrome (SARS) was identified in 2003, which raised concern about coronaviruses as agents of serious infectious disease. Nevertheless, coronaviruses have been known for about 50 years to be major agents of respiratory, enteric, or systemic infections of domestic and companion animals. Feline and canine coronaviruses are widespread among dog and cat populations, sometimes leading to the fatal diseases known as feline infectious peritonitis (FIP) and pantropic canine coronavirus infection in cats and dogs, respectively. In this paper, different aspects of the genetics, host cell tropism, and pathogenesis of the feline and canine coronaviruses (FCoV and CCoV) will be discussed, with a view to illustrating how study of FCoVs and CCoVs can improve our general understanding of the pathobiology of coronaviruses. PMID:22312347

  16. Feline and canine coronaviruses: common genetic and pathobiological features.

    PubMed

    Le Poder, Sophie

    2011-01-01

    A new human coronavirus responsible for severe acute respiratory syndrome (SARS) was identified in 2003, which raised concern about coronaviruses as agents of serious infectious disease. Nevertheless, coronaviruses have been known for about 50 years to be major agents of respiratory, enteric, or systemic infections of domestic and companion animals. Feline and canine coronaviruses are widespread among dog and cat populations, sometimes leading to the fatal diseases known as feline infectious peritonitis (FIP) and pantropic canine coronavirus infection in cats and dogs, respectively. In this paper, different aspects of the genetics, host cell tropism, and pathogenesis of the feline and canine coronaviruses (FCoV and CCoV) will be discussed, with a view to illustrating how study of FCoVs and CCoVs can improve our general understanding of the pathobiology of coronaviruses.

  17. Pre-mRNA Processing Factor Prp18 Is a Stimulatory Factor of Influenza Virus RNA Synthesis and Possesses Nucleoprotein Chaperone Activity.

    PubMed

    Minakuchi, M; Sugiyama, K; Kato, Y; Naito, T; Okuwaki, M; Kawaguchi, A; Nagata, K

    2017-02-01

    The genome of influenza virus (viral RNA [vRNA]) is associated with the nucleoprotein (NP) and viral RNA-dependent RNA polymerases and forms helical viral ribonucleoprotein (vRNP) complexes. The NP-vRNA complex is the biologically active template for RNA synthesis by the viral polymerase. Previously, we identified human pre-mRNA processing factor 18 (Prp18) as a stimulatory factor for viral RNA synthesis using a Saccharomyces cerevisiae replicon system and a single-gene deletion library of Saccharomyces cerevisiae (T. Naito, Y. Kiyasu, K. Sugiyama, A. Kimura, R. Nakano, A. Matsukage, and K. Nagata, Proc Natl Acad Sci USA, 104:18235-18240, 2007, https://doi.org/10.1073/pnas.0705856104). In infected Prp18 knockdown (KD) cells, the synthesis of vRNA, cRNA, and viral mRNAs was reduced. Prp18 was found to stimulate in vitro viral RNA synthesis through its interaction with NP. Analyses using in vitro RNA synthesis reactions revealed that Prp18 dissociates newly synthesized RNA from the template after the early elongation step to stimulate the elongation reaction. We found that Prp18 functions as a chaperone for NP to facilitate the formation of NP-RNA complexes. Based on these results, it is suggested that Prp18 accelerates influenza virus RNA synthesis as an NP chaperone for the processive elongation reaction. Templates for viral RNA synthesis of negative-stranded RNA viruses are not naked RNA but rather RNA encapsidated by viral nucleocapsid proteins forming vRNP complexes. However, viral basic proteins tend to aggregate under physiological ionic strength without chaperones. We identified the pre-mRNA processing factor Prp18 as a stimulatory factor for influenza virus RNA synthesis. We found that one of the targets of Prp18 is NP. Prp18 facilitates the elongation reaction of viral polymerases by preventing the deleterious annealing of newly synthesized RNA to the template. Prp18 functions as a chaperone for NP to stimulate the formation of NP-RNA complexes. Based on

  18. Bat Coronaviruses and Experimental Infection of Bats, the Philippines

    PubMed Central

    Watanabe, Shumpei; Masangkay, Joseph S.; Nagata, Noriyo; Morikawa, Shigeru; Mizutani, Tetsuya; Fukushi, Shuetsu; Alviola, Phillip; Omatsu, Tsutomu; Ueda, Naoya; Iha, Koichiro; Taniguchi, Satoshi; Fujii, Hikaru; Tsuda, Shumpei; Endoh, Maiko; Kato, Kentaro; Tohya, Yukinobu; Kyuwa, Shigeru; Yoshikawa, Yasuhiro

    2010-01-01

    Fifty-two bats captured during July 2008 in the Philippines were tested by reverse transcription–PCR to detect bat coronavirus (CoV) RNA. The overall prevalence of virus RNA was 55.8%. We found 2 groups of sequences that belonged to group 1 (genus Alphacoronavirus) and group 2 (genus Betacoronavirus) CoVs. Phylogenetic analysis of the RNA-dependent RNA polymerase gene showed that groups 1 and 2 CoVs were similar to Bat-CoV/China/A515/2005 (95% nt sequence identity) and Bat-CoV/HKU9–1/China/2007 (83% identity), respectively. To propagate group 2 CoVs obtained from a lesser dog-faced fruit bat (Cynopterus brachyotis), we administered intestine samples orally to Leschenault rousette bats (Rousettus leschenaulti) maintained in our laboratory. After virus replication in the bats was confirmed, an additional passage of the virus was made in Leschenault rousette bats, and bat pathogenesis was investigated. Fruit bats infected with virus did not show clinical signs of infection. PMID:20678314

  19. Bat coronaviruses and experimental infection of bats, the Philippines.

    PubMed

    Watanabe, Shumpei; Masangkay, Joseph S; Nagata, Noriyo; Morikawa, Shigeru; Mizutani, Tetsuya; Fukushi, Shuetsu; Alviola, Phillip; Omatsu, Tsutomu; Ueda, Naoya; Iha, Koichiro; Taniguchi, Satoshi; Fujii, Hikaru; Tsuda, Shumpei; Endoh, Maiko; Kato, Kentaro; Tohya, Yukinobu; Kyuwa, Shigeru; Yoshikawa, Yasuhiro; Akashi, Hiroomi

    2010-08-01

    Fifty-two bats captured during July 2008 in the Philippines were tested by reverse transcription-PCR to detect bat coronavirus (CoV) RNA. The overall prevalence of virus RNA was 55.8%. We found 2 groups of sequences that belonged to group 1 (genus Alphacoronavirus) and group 2 (genus Betacoronavirus) CoVs. Phylogenetic analysis of the RNA-dependent RNA polymerase gene showed that groups 1 and 2 CoVs were similar to Bat-CoV/China/A515/2005 (95% nt sequence identity) and Bat-CoV/HKU9-1/China/2007 (83% identity), respectively. To propagate group 2 CoVs obtained from a lesser dog-faced fruit bat (Cynopterus brachyotis), we administered intestine samples orally to Leschenault rousette bats (Rousettus leschenaulti) maintained in our laboratory. After virus replication in the bats was confirmed, an additional passage of the virus was made in Leschenault rousette bats, and bat pathogenesis was investigated. Fruit bats infected with virus did not show clinical signs of infection.

  20. Control of RNA synthesis in Escherichia coli after a shift to higher temperature.

    PubMed Central

    Ryals, J; Little, R; Bremer, H

    1982-01-01

    Parameters of RNA synthesis were measured after a temperature upshift in a pair of Escherichia coli B/r strains that are isogenic except for having relA and relA+ loci, to examine the cause for a reported anomaly in the correlation between guanosine tetraphosphate (ppGpp) and stable RNA (rRNA, tRNA) synthesis under such conditions. Two main results were: (i) the specific stable RNA gene activity (stable RNA per total RNA synthesis) correlated in the conventionally expected fashion with the level of ppGpp but was obscured by a nonspecific increase in the RNA chain elongation rate due to the higher temperature; (ii) the temperature upshift caused a transient reduction in the RNA polymerase activity (transcribing per total enzyme) that accounts for the previously observed oscillating RNA synthesis rate after a temperature shift. PMID:6179925

  1. Synthesis of RNA oligomers on heterogeneous templates

    NASA Technical Reports Server (NTRS)

    Ertem, G.; Ferris, J. P.

    1996-01-01

    The concept of an RNA world in the chemical origin of life is appealing, as nucleic acids are capable of both information storage and acting as templates that catalyse the synthesis of complementary molecules. Template-directed synthesis has been demonstrated for homogeneous oligonucleotides that, like natural nucleic acids, have 3',5' linkages between the nucleotide monomers. But it seems likely that prebiotic routes to RNA-like molecules would have produced heterogeneous molecules with various kinds of phosphodiester linkages and both linear and cyclic nucleotide chains. Here we show that such heterogeneity need be no obstacle to the templating of complementary molecules. Specifically, we show that heterogeneous oligocytidylates, formed by the montmorillonite clay-catalysed condensation of actuated monomers, can serve as templates for the synthesis of oligoguanylates. Furthermore, we show that oligocytidylates that are exclusively 2',5'-linked can also direct synthesis of oligoguanylates. Such heterogeneous templating reactions could have increased the diversity of the pool of protonucleic acids from which life ultimately emerged.

  2. Origins of tmRNA: the missing link in the birth of protein synthesis?

    PubMed

    Macé, Kevin; Gillet, Reynald

    2016-09-30

    The RNA world hypothesis refers to the early period on earth in which RNA was central in assuring both genetic continuity and catalysis. The end of this era coincided with the development of the genetic code and protein synthesis, symbolized by the apparition of the first non-random messenger RNA (mRNA). Modern transfer-messenger RNA (tmRNA) is a unique hybrid molecule which has the properties of both mRNA and transfer RNA (tRNA). It acts as a key molecule during trans-translation, a major quality control pathway of modern bacterial protein synthesis. tmRNA shares many common characteristics with ancestral RNA. Here, we present a model in which proto-tmRNAs were the first molecules on earth to support non-random protein synthesis, explaining the emergence of early genetic code. In this way, proto-tmRNA could be the missing link between the first mRNA and tRNA molecules and modern ribosome-mediated protein synthesis. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. NUCLEAR ENVELOPE-ASSOCIATED RESUMPTION OF RNA SYNTHESIS IN LATE MITOSIS OF HELA CELLS

    PubMed Central

    Simmons, T.; Heywood, P.; Hodge, L.

    1973-01-01

    The restitution of RNA synthesis in cultures progressing from metaphase into interphase (G1) has been investigated in synchronized HeLa S3 cells by using inhibitors of macro-molecular synthesis and the technique of electron microscope autoradiography. The rate of incorporation of radioactive uridine into RNA approached interphase levels in the absence of renewed protein synthesis. In contrast, maintenance of this rate in G1 was dependent upon renewed protein synthesis. Restoration of synthesis of heterogeneous nuclear RNA occurred under conditions that inhibited production of ribosomal precursor RNA. In autoradiographs of individual cells exposed to radioactive uridine, silver grains were first detected after nuclear envelope reformation at the periphery of the chromosome mass but before chromosomal decondensation. These data are consistent with the following interpretation. Multiple RNA polymerase activities persist through mitosis and are involved in the initiation of RNA synthesis in early telophase at sites on the nuclear envelope. PMID:4752403

  4. Survey of feline leukemia virus and feline coronaviruses in captive neotropical wild felids from Southern Brazil.

    PubMed

    Guimaraes, Ana M S; Brandão, Paulo E; de Moraes, Wanderlei; Cubas, Zalmir S; Santos, Leonilda C; Villarreal, Laura Y B; Robes, Rogério R; Coelho, Fabiana M; Resende, Mauricio; Santos, Renata C F; Oliveira, Rosangela C; Yamaguti, Mauricio; Marques, Lucas M; Neto, Renata L; Buzinhani, Melissa; Marques, Regina; Messick, Joanne B; Biondo, Alexander W; Timenetsky, Jorge

    2009-06-01

    A total of 57 captive neotropical felids (one Leopardus geoffroyi, 14 Leopardus pardalis, 17 Leopardus wiedii, 22 Leopardus tigrinus, and three Puma yagouaroundi) from the Itaipu Binacional Wildlife Research Center (Refúgio Bela Vista, Southern Brazil) were anesthetized for blood collection. Feces samples were available for 44 animals, including one L. geoffroyi, eight L. pardalis, 14 L. wiedii, 20 L. tigrinus, and one P. yagouaroundi. Total DNA and RNA were extracted from blood and feces, respectively, using commercial kits. Blood DNA samples were evaluated by polymerase chain reaction (PCR) for feline leukemia virus (FeLV) proviral DNA, whereas reverse transcriptase-PCR was run on fecal samples for detection of coronavirus RNA. None of the samples were positive for coronaviruses. A male L. pardalis and a female L. tigrinus were positive for FeLV proviral DNA, and identities of PCR products were confirmed by sequencing. This is the first evidence of FeLV proviral DNA in these species in Southern Brazil.

  5. [Effect of metalaxyl on the synthesis of RNA, DNA and protein in Phytophthora nicotianae].

    PubMed

    Wollgiehn, R; Bräutigam, E; Schumann, B; Erge, D

    1984-01-01

    Metalaxyl is used to control diseases caused by fungi of the order of the Perenosporales. We investigated the action of this fungicid eon nucleic acid and protein synthesis in liquid cultures of Phytophthora nicotianae. The uptake of 32P, 3H-uridine, 3H-thymidine and 14C-leucine as precursors of nuclei acid and protein synthesis by the mycelium was not inhibited by metalaxyl. RNA synthesis as indicated by 3H-uridine incorporation was strongly inhibited (about 80%) by 0.5 micrograms/ml of metalaxyl. The inhibition was visible already few minutes after addition of the toxicant. Since the inhibition of incorporation of 3H-thymidine into DNA and of 14C-leucine into protein became significant 2-3 hours later, we conclude that metalaxyl primarily interfers with RNA synthesis. Synthesis of ribosomal RNA is more affected (more than 90%) than that of tRNA (about 55%) and poly(A)-containing RNA. Since in the presence of actinomycin, in contrast to metalaxyl, protein synthesis is inhibited immediately as a consequence of complete inhibition of RNA synthesis and of the short life-time of mRNA, it is also evident that mRNA synthesis is less strongly inhibited, at least during the early period of metalaxyl action. The molecular mechanism of metalaxyl inhibition of the transcription process remains open. The fungicide did not inhibit the activity of a partially purified RNA polymerase isolated from the fungus. On the other hand, the RNA synthesis (14C-UTP-incorporation) by a cell homogenate and by isolated nuclear fractions was inhibited significantly. Possibilities of the molecular action of metalaxyl are discussed. The RNA synthesis of some plant systems (cell cultures of Lycopersicon peruvianum, isolated nuclei from the same cell cultures, purified RNA polymerase from Spinacia oleracea chloroplasts) was not inhibited by metalaxyl, not even at high concentrations.

  6. Detection of coronavirus genomes in Moluccan naked-backed fruit bats in Indonesia.

    PubMed

    Anindita, Paulina Duhita; Sasaki, Michihito; Setiyono, Agus; Handharyani, Ekowati; Orba, Yasuko; Kobayashi, Shintaro; Rahmadani, Ibnu; Taha, Siswatiana; Adiani, Sri; Subangkit, Mawar; Nakamura, Ichiro; Sawa, Hirofumi; Kimura, Takashi

    2015-04-01

    Bats have been shown to serve as natural reservoirs for numerous emerging viruses including severe acute respiratory syndrome coronavirus (SARS-CoV). In the present study, we report the discovery of bat CoV genes in Indonesian Moluccan naked-backed fruit bats (Dobsonia moluccensis). A partial RNA-dependent RNA polymerase gene sequence was detected in feces and tissues samples from the fruit bats, and the region between the RdRp and helicase genes could also be amplified from fecal samples. Phylogenetic analysis suggested that these bat CoVs are related to members of the genus Betacoronavirus.

  7. Coronavirus infections in horses in Saudi Arabia and Oman.

    PubMed

    Hemida, M G; Chu, D K W; Perera, R A P M; Ko, R L W; So, R T Y; Ng, B C Y; Chan, S M S; Chu, S; Alnaeem, A A; Alhammadi, M A; Webby, R J; Poon, L L M; Balasuriya, U B R; Peiris, M

    2017-12-01

    Equine coronaviruses (ECoV) are the only coronavirus known to infect horses. So far, data on ECoV infection in horses remain limited to the USA, France and Japan and its geographic distribution is not well understood. We carried out RT-PCR on 306 nasal and 315 rectal swabs and tested 243 sera for antibodies to detect coronavirus infections in apparently healthy horses in Saudi Arabia and Oman. We document evidence of infection with ECoV and HKU23 coronavirus by RT-PCR. There was no conclusive evidence of Middle East respiratory syndrome coronavirus infection in horses. Serological data suggest that lineage A betacoronavirus infections are commonly infecting horses in Saudi Arabia and Oman but antibody cross-reactivities between these viruses do not permit us to use serological data alone to identify which coronaviruses are causing these infections. © 2017 Blackwell Verlag GmbH.

  8. Enzymatic Synthesis of Self-assembled Dicer Substrate RNA Nanostructures for Programmable Gene Silencing.

    PubMed

    Jang, Bora; Kim, Boyoung; Kim, Hyunsook; Kwon, Hyokyoung; Kim, Minjeong; Seo, Yunmi; Colas, Marion; Jeong, Hansaem; Jeong, Eun Hye; Lee, Kyuri; Lee, Hyukjin

    2018-06-08

    Enzymatic synthesis of RNA nanostructures is achieved by isothermal rolling circle transcription (RCT). Each arm of RNA nanostructures provides a functional role of Dicer substrate RNA inducing sequence specific RNA interference (RNAi). Three different RNAi sequences (GFP, RFP, and BFP) are incorporated within the three-arm junction RNA nanostructures (Y-RNA). The template and helper DNA strands are designed for the large-scale in vitro synthesis of RNA strands to prepare self-assembled Y-RNA. Interestingly, Dicer processing of Y-RNA is highly influenced by its physical structure and different gene silencing activity is achieved depending on its arm length and overhang. In addition, enzymatic synthesis allows the preparation of various Y-RNA structures using a single DNA template offering on demand regulation of multiple target genes.

  9. Understanding bat SARS-like coronaviruses for the preparation of future coronavirus outbreaks - Implications for coronavirus vaccine development.

    PubMed

    Ng, Oi-Wing; Tan, Yee-Joo

    2017-01-02

    The severe acute respiratory syndrome coronavirus (SARS-CoV) first emerged in 2003, causing the SARS epidemic which resulted in a 10% fatality rate. The advancements in metagenomic techniques have allowed the identification of SARS-like coronaviruses (SL-CoVs) sequences that share high homology to the human SARS-CoV epidemic strains from wildlife bats, presenting concrete evidence that bats are the origin and natural reservoir of SARS-CoV. The application of reverse genetics further enabled that characterization of these bat CoVs and the prediction of their potential to cause disease in humans. The knowledge gained from such studies is valuable in the surveillance and preparation of a possible future outbreak caused by a spill-over of these bat SL-CoVs.

  10. Cell-penetrating peptide-morpholino conjugates alter pre-mRNA splicing of DMD (Duchenne muscular dystrophy) and inhibit murine coronavirus replication in vivo.

    PubMed

    Moulton, H M; Fletcher, S; Neuman, B W; McClorey, G; Stein, D A; Abes, S; Wilton, S D; Buchmeier, M J; Lebleu, B; Iversen, P L

    2007-08-01

    The cellular uptake of PMOs (phosphorodiamidate morpholino oligomers) can be enhanced by their conjugation to arginine-rich CPPs (cell-penetrating peptides). Here, we discuss our recent findings regarding (R-Ahx-R)(4)AhxB (Ahx is 6-aminohexanoic acid and B is beta-alanine) CPP-PMO conjugates in DMD (Duchenne muscular dystrophy) and murine coronavirus research. An (R-Ahx-R)(4)AhxB-PMO conjugate was the most effective compound in inducing the correction of mutant dystrophin transcripts in myoblasts derived from a canine model of DMD. Similarly, normal levels of dystrophin expression were restored in the diaphragms of mdx mice, with treatment starting at the neonatal stage, and protein was still detecTable 22 weeks after the last dose of an (R-Ahx-R)(4)AhxB-PMO conjugate. Effects of length, linkage and carbohydrate modification of this CPP on the delivery of a PMO were investigated in a coronavirus mouse model. An (R-Ahx-R)(4)AhxB-PMO conjugate effectively inhibited viral replication, in comparison with other peptides conjugated to the same PMO. Shortening the CPP length, modifying it with a mannosylated serine moiety or replacing it with the R(9)F(2) CPP significantly decreased the efficacy of the resulting PPMO (CPP-PMO conjugate). We attribute the success of this CPP to its stability in serum and its capacity to transport PMO to RNA targets in a manner superior to that of poly-arginine CPPs.

  11. Coronavirus 229E-related pneumonia in immunocompromised patients.

    PubMed

    Pene, Frédéric; Merlat, Annabelle; Vabret, Astrid; Rozenberg, Flore; Buzyn, Agnès; Dreyfus, François; Cariou, Alain; Freymuth, François; Lebon, Pierre

    2003-10-01

    Coronaviruses strains 229E and OC43 have been associated with various respiratory illnesses ranging from the self-resolving common cold to severe pneumonia. Although chronic underlying conditions are major determinants of severe respiratory virus infections, few data about coronavirus-related pneumonia in immunocompromised patients are available. Here we report 2 well-documented cases of pneumonia related to coronavirus 229E, each with a different clinical presentation. Diagnosis was made on the basis of viral culture and electron microscopy findings that exhibited typical crown-like particles and through amplification of the viral genome by reverse transcriptase-polymerase chain reaction. On the basis of this report, coronaviruses should be considered as potential causative microorganisms of pneumonia in immunocompromised patients.

  12. Biodiversity impact of host interferon-stimulated-gene-product 15 on the coronavirus Papain-like protease deISGylase functions

    USDA-ARS?s Scientific Manuscript database

    Coronaviruses are single-stranded, positive sense RNA viruses whose members have severe impact on human health and cause significant economic hardships. Some pertinent examples include severe acute and Middle East respiratory syndromes (SARS-CoV; MERS-CoV), porcine epidemic diarrhea virus (PEDV), an...

  13. Coronavirus Infection and Diversity in Bats in the Australasian Region.

    PubMed

    Smith, C S; de Jong, C E; Meers, J; Henning, J; Wang, L- F; Field, H E

    2016-03-01

    Following the SARS outbreak, extensive surveillance was undertaken globally to detect and identify coronavirus diversity in bats. This study sought to identify the diversity and prevalence of coronaviruses in bats in the Australasian region. We identified four different genotypes of coronavirus, three of which (an alphacoronavirus and two betacoronaviruses) are potentially new species, having less than 90% nucleotide sequence identity with the most closely related described viruses. We did not detect any SARS-like betacoronaviruses, despite targeting rhinolophid bats, the putative natural host taxa. Our findings support the virus-host co-evolution hypothesis, with the detection of Miniopterus bat coronavirus HKU8 (previously reported in Miniopterus species in China, Hong Kong and Bulgaria) in Australian Miniopterus species. Similarly, we detected a novel betacoronavirus genotype from Pteropus alecto which is most closely related to Bat coronavirus HKU9 identified in other pteropodid bats in China, Kenya and the Philippines. We also detected possible cross-species transmission of bat coronaviruses, and the apparent enteric tropism of these viruses. Thus, our findings are consistent with a scenario wherein the current diversity and host specificity of coronaviruses reflects co-evolution with the occasional host shift.

  14. [Influence of antisense RNA and sequences of viral transactivators traps on RNA synthesis of HTLV-1 virus].

    PubMed

    Borisenko, A S; Kotus, E V; Kaloshin, A A

    2008-01-01

    Significant number of scientific publications devoted to inhibition of viral replication by antisense RNA (asRNA) genes shows that this approach is useful for gene therapy of viral infections. To investigate the possibility of suppression of HTLV-1 virus reproduction by asRNA we constructed recombinant plasmids containing asRNA genes against U3 long terminal repeats region and X gene under the control of promoter of myeloproliferative sarcoma virus (MPSV) or without such promoter. Using stable calcium-phosphate transfection method with subsequent selection in the presence of G-418, RaHOS line-based cell clones carrying both asRNA genes and sequences able to bind HTLV-1 transactivator proteins (i.e. "traps" of viral transactivators, TVT) were obtained. Data from dot-hybridization analysis of viral RNA extracted from RaHOS cell clones showed that TVT sequences are able to suppress the viral RNA synthesis on 90% and asRNA against X gene synthesis--on 50%.

  15. Recombinant viral RdRps can initiate RNA synthesis from circular templates

    PubMed Central

    RANJITH-KUMAR, C.T.; KAO, C.C.

    2006-01-01

    The crystal structure of the recombinant hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) revealed extensive interactions between the fingers and the thumb subdomains, resulting in a closed conformation with an established template channel that should specifically accept single-stranded templates. We made circularized RNA templates and found that they were efficiently used by the HCV RdRp to synthesize product RNAs that are significantly longer than the template, suggesting that RdRp could exist in an open conformation prior to template binding. RNA synthesis using circular RNA templates had properties similar to those previously documented for linear RNA, including a need for higher GTP concentration for initiation, usage of GTP analogs, sensitivity to salt, and involvement of active-site residues for product formation. Some products were resistant to challenge with the template competitor heparin, indicating that the elongation complexes remain bound to template and are competent for RNA synthesis. Other products were not elongated in the presence of heparin, indicating that the elongation complex was terminated. Lastly, recombinant RdRps from two other flaviviruses and from the Pseudomonas phage φ6 also could use circular RNA templates for RNA-dependent RNA synthesis, although the φ6 RdRp could only use circular RNAs made from the 3′-terminal sequence of the φ6 genome. PMID:16373481

  16. SARS and MERS: recent insights into emerging coronaviruses.

    PubMed

    de Wit, Emmie; van Doremalen, Neeltje; Falzarano, Darryl; Munster, Vincent J

    2016-08-01

    The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 marked the second introduction of a highly pathogenic coronavirus into the human population in the twenty-first century. The continuing introductions of MERS-CoV from dromedary camels, the subsequent travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality rates highlight the need for prophylactic and therapeutic measures. Scientific advancements since the 2002-2003 severe acute respiratory syndrome coronavirus (SARS-CoV) pandemic allowed for rapid progress in our understanding of the epidemiology and pathogenesis of MERS-CoV and the development of therapeutics. In this Review, we detail our present understanding of the transmission and pathogenesis of SARS-CoV and MERS-CoV, and discuss the current state of development of measures to combat emerging coronaviruses.

  17. [Cell entry mechanisms of coronaviruses].

    PubMed

    Taguchi, Fumihiro; Matsuyama, Shutoku

    2009-12-01

    Enveloped viruses enter into cells via fusion of their envelope and cellular membrane. Spike (S) protein of coronavirus (CoV) is responsible for entry events. We studied the cell entry mechanisms of two different CoVs, murine coronavirus mouse hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus (SARS-CoV). MHV-JHM that induces syncytia in infected cells entered directly from cell surface, i.e., fusion of envelope and plasma membrane, whereas SARS-CoV and MHV-2 that fail to induce syncytia entered via endosome in a protease-dependent fashion, i.e., fusion of envelope and endosomal membrane. The latter viruses entered directly from cell surface, when receptor-bound viruses were treated with proteases that activate fusion activity of their S proteins. The entry pathway of SARS-CoV could influence the severity of the disease. It was also reveled that a highly neurovirulent JHM spread in a receptor-independent fashion, which could result in a high neuropathogenicity of the virus.

  18. A molecular arms race between host innate antiviral response and emerging human coronaviruses.

    PubMed

    Wong, Lok-Yin Roy; Lui, Pak-Yin; Jin, Dong-Yan

    2016-02-01

    Coronaviruses have been closely related with mankind for thousands of years. Community-acquired human coronaviruses have long been recognized to cause common cold. However, zoonotic coronaviruses are now becoming more a global concern with the discovery of highly pathogenic severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses causing severe respiratory diseases. Infections by these emerging human coronaviruses are characterized by less robust interferon production. Treatment of patients with recombinant interferon regimen promises beneficial outcomes, suggesting that compromised interferon expression might contribute at least partially to the severity of disease. The mechanisms by which coronaviruses evade host innate antiviral response are under intense investigations. This review focuses on the fierce arms race between host innate antiviral immunity and emerging human coronaviruses. Particularly, the host pathogen recognition receptors and the signal transduction pathways to mount an effective antiviral response against SARS and MERS coronavirus infection are discussed. On the other hand, the counter-measures evolved by SARS and MERS coronaviruses to circumvent host defense are also dissected. With a better understanding of the dynamic interaction between host and coronaviruses, it is hoped that insights on the pathogenesis of newly-identified highly pathogenic human coronaviruses and new strategies in antiviral development can be derived.

  19. Heat shock represses rRNA synthesis by inactivation of TIF-IA and lncRNA-dependent changes in nucleosome positioning.

    PubMed

    Zhao, Zhongliang; Dammert, Marcel A; Hoppe, Sven; Bierhoff, Holger; Grummt, Ingrid

    2016-09-30

    Attenuation of ribosome biogenesis in suboptimal growth environments is crucial for cellular homeostasis and genetic integrity. Here, we show that shutdown of rRNA synthesis in response to elevated temperature is brought about by mechanisms that target both the RNA polymerase I (Pol I) transcription machinery and the epigenetic signature of the rDNA promoter. Upon heat shock, the basal transcription factor TIF-IA is inactivated by inhibition of CK2-dependent phosphorylations at Ser170/172. Attenuation of pre-rRNA synthesis in response to heat stress is accompanied by upregulation of PAPAS, a long non-coding RNA (lncRNA) that is transcribed in antisense orientation to pre-rRNA. PAPAS interacts with CHD4, the adenosine triphosphatase subunit of NuRD, leading to deacetylation of histones and movement of the promoter-bound nucleosome into a position that is refractory to transcription initiation. The results exemplify how stress-induced inactivation of TIF-IA and lncRNA-dependent changes of chromatin structure ensure repression of rRNA synthesis in response to thermo-stress. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  20. T-cell-mediated immune response to respiratory coronaviruses

    PubMed Central

    Channappanavar, Rudragouda; Zhao, Jincun; Perlman, Stanley

    2014-01-01

    Emerging respiratory coronaviruses such as the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and Middle East Respiratory Syndrome coronavirus (MERS-CoV) pose potential biological threats to humans. SARS and MERS are manifested as severe atypical pneumonia associated with high morbidity and mortality in humans. The majority of studies carried out in SARS-CoV-infected humans and animals attribute a dysregulated/exuberant innate response as a leading contributor to SARS-CoV-mediated pathology. A decade after the 2002–2003 SARS epidemic, we do not have any approved preventive or therapeutic agents available in case of re-emergence of SARS-CoV or other related viruses. A strong neutralizing antibody response generated against the spike (S) glycoprotein of SARS-CoV is completely protective in the susceptible host. However, neutralizing antibody titers and the memory B cell response are short-lived in SARS-recovered patients and the antibody will target primary homologous strain. Interestingly, the acute phase of SARS in humans is associated with a severe reduction in the number of T cells in the blood. Surprisingly, only a limited number of studies have explored the role of the T cell-mediated adaptive immune response in respiratory coronavirus pathogenesis. In this review, we discuss the role of anti-virus CD4 and CD8 T cells during respiratory coronavirus infections with a special emphasis on emerging coronaviruses. PMID:24845462

  1. The synthesis of polyadenylated messenger RNA in herpes simplex type I virus infected BHK cells.

    PubMed

    Harris, T J; Wildy, P

    1975-09-01

    The pattern of polyadenylated messenger RNA (mRNA) synthesis in BHK cell monolayers, infected under defined conditions with herpes simplex type I virus has been investigated by polyacrylamide gel electrophoresis or pulse-labelled RNA isolated by oligo dT-cellulose chromatography. Two classes of mRNA molecules were synthesized in infected cells; these were not detected in uninfected cells. The rate of synthesis of the larger, 18 to 30S RNA class reached a maximum soon after injection and then declined, whereas the rate of synthesis of the 7 to 11 S RNA class did not reach a maximum until much later and did not decline. In the presence of cytosine arabinoside, the rate of mRNA synthesis in infected cells was reduced but the electrophoretic pattern remained the same.

  2. Abelson Kinase Inhibitors Are Potent Inhibitors of Severe Acute Respiratory Syndrome Coronavirus and Middle East Respiratory Syndrome Coronavirus Fusion

    PubMed Central

    Coleman, Christopher M.; Sisk, Jeanne M.; Mingo, Rebecca M.; Nelson, Elizabeth A.; White, Judith M.

    2016-01-01

    ABSTRACT The highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) cause significant morbidity and morality. There is currently no approved therapeutic for highly pathogenic coronaviruses, even as MERS-CoV is spreading throughout the Middle East. We previously screened a library of FDA-approved drugs for inhibitors of coronavirus replication in which we identified Abelson (Abl) kinase inhibitors, including the anticancer drug imatinib, as inhibitors of both SARS-CoV and MERS-CoV in vitro. Here we show that the anti-CoV activity of imatinib occurs at the early stages of infection, after internalization and endosomal trafficking, by inhibiting fusion of the virions at the endosomal membrane. We specifically identified the imatinib target, Abelson tyrosine-protein kinase 2 (Abl2), as required for efficient SARS-CoV and MERS-CoV replication in vitro. These data demonstrate that specific approved drugs can be characterized in vitro for their anticoronavirus activity and used to identify host proteins required for coronavirus replication. This type of study is an important step in the repurposing of approved drugs for treatment of emerging coronaviruses. IMPORTANCE Both SARS-CoV and MERS-CoV are zoonotic infections, with bats as the primary source. The 2003 SARS-CoV outbreak began in Guangdong Province in China and spread to humans via civet cats and raccoon dogs in the wet markets before spreading to 37 countries. The virus caused 8,096 confirmed cases of SARS and 774 deaths (a case fatality rate of ∼10%). The MERS-CoV outbreak began in Saudi Arabia and has spread to 27 countries. MERS-CoV is believed to have emerged from bats and passed into humans via camels. The ongoing outbreak of MERS-CoV has resulted in 1,791 cases of MERS and 640 deaths (a case fatality rate of 36%). The emergence of SARS-CoV and MERS-CoV provides evidence that coronaviruses are currently spreading from zoonotic

  3. Synthesis and biological activity of artificial mRNA prepared with novel phosphorylating reagents

    PubMed Central

    Nagata, Seigo; Hamasaki, Tomohiro; Uetake, Koichi; Masuda, Hirofumi; Takagaki, Kazuchika; Oka, Natsuhisa; Wada, Takeshi; Ohgi, Tadaaki; Yano, Junichi

    2010-01-01

    Though medicines that target mRNA are under active investigation, there has been little or no effort to develop mRNA itself as a medicine. Here, we report the synthesis of a 130-nt mRNA sequence encoding a 33-amino-acid peptide that includes the sequence of glucagon-like peptide-1, a peptide that stimulates glucose-dependent insulin secretion from the pancreas. The synthesis method used, which had previously been developed in our laboratory, was based on the use of 2-cyanoethoxymethyl as the 2′-hydroxy protecting group. We also developed novel, highly reactive phosphotriester pyrophosphorylating reagents to pyrophosphorylate the 5′-end of the 130-mer RNA in preparation for capping. We completed the synthesis of the artificial mRNA by the enzymatic addition of a 5′-cap and a 3′-poly(A) tail to the pyrophosphorylated 130-mer and showed that the resulting mRNA supported protein synthesis in a cell-free system and in whole cells. As far as we know, this is the first time that mRNA has been prepared from a chemically synthesized RNA sequence. As well as providing a research tool for the intracellular expression of peptides, the technology described here may be used for the production of mRNA for medical applications. PMID:20660478

  4. Recombination in Avian Gamma-Coronavirus Infectious Bronchitis Virus

    PubMed Central

    Thor, Sharmi W.; Hilt, Deborah A.; Kissinger, Jessica C.; Paterson, Andrew H.; Jackwood, Mark W.

    2011-01-01

    Recombination in the family Coronaviridae has been well documented and is thought to be a contributing factor in the emergence and evolution of different coronaviral genotypes as well as different species of coronavirus. However, there are limited data available on the frequency and extent of recombination in coronaviruses in nature and particularly for the avian gamma-coronaviruses where only recently the emergence of a turkey coronavirus has been attributed solely to recombination. In this study, the full-length genomes of eight avian gamma-coronavirus infectious bronchitis virus (IBV) isolates were sequenced and along with other full-length IBV genomes available from GenBank were analyzed for recombination. Evidence of recombination was found in every sequence analyzed and was distributed throughout the entire genome. Areas that have the highest occurrence of recombination are located in regions of the genome that code for nonstructural proteins 2, 3 and 16, and the structural spike glycoprotein. The extent of the recombination observed, suggests that this may be one of the principal mechanisms for generating genetic and antigenic diversity within IBV. These data indicate that reticulate evolutionary change due to recombination in IBV, likely plays a major role in the origin and adaptation of the virus leading to new genetic types and strains of the virus. PMID:21994806

  5. Virus-Specific RNA Synthesis in Cells Infected by Infectious Pancreatic Necrosis Virus

    PubMed Central

    Somogyi, Paul; Dobos, Peter

    1980-01-01

    Pulse-labeling experiments with [3H]uridine revealed that the rate of infections pancreatic necrosis virus-specific RNA synthesis was maximal at 8 to 10 h after infection and was completely diminished by 12 to 14 h. Three forms of RNA intermediates were detected: (i) a putative transcription intermediate (TRI) which comigrated in acrylamide gels with virion double-stranded RNA (dsRNA) after RNase treatment; (ii) a 24S genome length mRNA which could be resolved into two bands by polyacrylamide gel electrophoresis; and (iii) a 14S dsRNA component indistinguishable from virion RNA by gradient centrifugation and gel electrophoresis. The TRI (i) was LiCl precipitable; (ii) sedimented slightly faster and broader (14 to 16S) than the 14S virion dsRNA; (iii) had a lower electrophoretic mobility in acrylamide gels than dsRNA, barely entering acrylamide gels as a heterogenous component; (iv) yielded genome-sized pieces of dsRNA after RNase digestion; and (v) was the most abundant RNA form early in the infectious cycle. The 24S single-stranded RNA was thought to be the viral mRNA since it: (i) became labeled during short pulses; (ii) was found in the polysomal fraction of infected cells; and (iii) hybridized to denatured viral RNA, forming two segments of RNase-resistant RNA that comigrated with virion dsRNA in gels. The 24S mRNA component was formed before the synthesis of dsRNA, and radioactivity could be chased from 24S single-stranded RNA to dsRNA, indicating that 24S RNA may serve as template for the synthesis of complementary strands to form dsRNA. Similar to reovirus, infectious pancreatic necrosis viral 24S mRNA contained no polyadenylic acid tracts. Images PMID:16789184

  6. An intrinsically disordered peptide from Ebola virus VP35 controls viral RNA synthesis by modulating nucleoprotein-RNA interactions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leung, Daisy  W.; Borek, Dominika; Luthra, Priya

    During viral RNA synthesis, Ebola virus (EBOV) nucleoprotein (NP) alternates between an RNA-template-bound form and a template-free form to provide the viral polymerase access to the RNA template. In addition, newly synthesized NP must be prevented from indiscriminately binding to noncognate RNAs. Here, we investigate the molecular bases for these critical processes. We identify an intrinsically disordered peptide derived from EBOV VP35 (NPBP, residues 20–48) that binds NP with high affinity and specificity, inhibits NP oligomerization, and releases RNA from NP-RNA complexes in vitro. The structure of the NPBP/ΔNP NTD complex, solved to 3.7 Å resolution, reveals how NPBP peptidemore » occludes a large surface area that is important for NP-NP and NP-RNA interactions and for viral RNA synthesis. Together, our results identify a highly conserved viral interface that is important for EBOV replication and can be targeted for therapeutic development.« less

  7. An intrinsically disordered peptide from Ebola virus VP35 controls viral RNA synthesis by modulating nucleoprotein-RNA interactions

    DOE PAGES

    Leung, Daisy  W.; Borek, Dominika; Luthra, Priya; ...

    2015-04-01

    During viral RNA synthesis, Ebola virus (EBOV) nucleoprotein (NP) alternates between an RNA-template-bound form and a template-free form to provide the viral polymerase access to the RNA template. In addition, newly synthesized NP must be prevented from indiscriminately binding to noncognate RNAs. Here, we investigate the molecular bases for these critical processes. We identify an intrinsically disordered peptide derived from EBOV VP35 (NPBP, residues 20–48) that binds NP with high affinity and specificity, inhibits NP oligomerization, and releases RNA from NP-RNA complexes in vitro. The structure of the NPBP/ΔNP NTD complex, solved to 3.7 Å resolution, reveals how NPBP peptidemore » occludes a large surface area that is important for NP-NP and NP-RNA interactions and for viral RNA synthesis. Together, our results identify a highly conserved viral interface that is important for EBOV replication and can be targeted for therapeutic development.« less

  8. An Intrinsically Disordered Peptide from Ebola Virus VP35 Controls Viral RNA Synthesis by Modulating Nucleoprotein-RNA Interactions.

    PubMed

    Leung, Daisy W; Borek, Dominika; Luthra, Priya; Binning, Jennifer M; Anantpadma, Manu; Liu, Gai; Harvey, Ian B; Su, Zhaoming; Endlich-Frazier, Ariel; Pan, Juanli; Shabman, Reed S; Chiu, Wah; Davey, Robert A; Otwinowski, Zbyszek; Basler, Christopher F; Amarasinghe, Gaya K

    2015-04-21

    During viral RNA synthesis, Ebola virus (EBOV) nucleoprotein (NP) alternates between an RNA-template-bound form and a template-free form to provide the viral polymerase access to the RNA template. In addition, newly synthesized NP must be prevented from indiscriminately binding to noncognate RNAs. Here, we investigate the molecular bases for these critical processes. We identify an intrinsically disordered peptide derived from EBOV VP35 (NPBP, residues 20-48) that binds NP with high affinity and specificity, inhibits NP oligomerization, and releases RNA from NP-RNA complexes in vitro. The structure of the NPBP/ΔNPNTD complex, solved to 3.7 Å resolution, reveals how NPBP peptide occludes a large surface area that is important for NP-NP and NP-RNA interactions and for viral RNA synthesis. Together, our results identify a highly conserved viral interface that is important for EBOV replication and can be targeted for therapeutic development. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  9. The Murine Norovirus Core Subgenomic RNA Promoter Consists of a Stable Stem-Loop That Can Direct Accurate Initiation of RNA Synthesis

    PubMed Central

    Yunus, Muhammad Amir; Lin, Xiaoyan; Bailey, Dalan; Karakasiliotis, Ioannis; Chaudhry, Yasmin; Vashist, Surender; Zhang, Guo; Thorne, Lucy; Kao, C. Cheng

    2014-01-01

    ABSTRACT All members of the Caliciviridae family of viruses produce a subgenomic RNA during infection. The subgenomic RNA typically encodes only the major and minor capsid proteins, but in murine norovirus (MNV), the subgenomic RNA also encodes the VF1 protein, which functions to suppress host innate immune responses. To date, the mechanism of norovirus subgenomic RNA synthesis has not been characterized. We have previously described the presence of an evolutionarily conserved RNA stem-loop structure on the negative-sense RNA, the complementary sequence of which codes for the viral RNA-dependent RNA polymerase (NS7). The conserved stem-loop is positioned 6 nucleotides 3′ of the start site of the subgenomic RNA in all caliciviruses. We demonstrate that the conserved stem-loop is essential for MNV viability. Mutant MNV RNAs with substitutions in the stem-loop replicated poorly until they accumulated mutations that revert to restore the stem-loop sequence and/or structure. The stem-loop sequence functions in a noncoding context, as it was possible to restore the replication of an MNV mutant by introducing an additional copy of the stem-loop between the NS7- and VP1-coding regions. Finally, in vitro biochemical data suggest that the stem-loop sequence is sufficient for the initiation of viral RNA synthesis by the recombinant MNV RNA-dependent RNA polymerase, confirming that the stem-loop forms the core of the norovirus subgenomic promoter. IMPORTANCE Noroviruses are a significant cause of viral gastroenteritis, and it is important to understand the mechanism of norovirus RNA synthesis. Here we describe the identification of an RNA stem-loop structure that functions as the core of the norovirus subgenomic RNA promoter in cells and in vitro. This work provides new insights into the molecular mechanisms of norovirus RNA synthesis and the sequences that determine the recognition of viral RNA by the RNA-dependent RNA polymerase. PMID:25392209

  10. The murine norovirus core subgenomic RNA promoter consists of a stable stem-loop that can direct accurate initiation of RNA synthesis.

    PubMed

    Yunus, Muhammad Amir; Lin, Xiaoyan; Bailey, Dalan; Karakasiliotis, Ioannis; Chaudhry, Yasmin; Vashist, Surender; Zhang, Guo; Thorne, Lucy; Kao, C Cheng; Goodfellow, Ian

    2015-01-15

    All members of the Caliciviridae family of viruses produce a subgenomic RNA during infection. The subgenomic RNA typically encodes only the major and minor capsid proteins, but in murine norovirus (MNV), the subgenomic RNA also encodes the VF1 protein, which functions to suppress host innate immune responses. To date, the mechanism of norovirus subgenomic RNA synthesis has not been characterized. We have previously described the presence of an evolutionarily conserved RNA stem-loop structure on the negative-sense RNA, the complementary sequence of which codes for the viral RNA-dependent RNA polymerase (NS7). The conserved stem-loop is positioned 6 nucleotides 3' of the start site of the subgenomic RNA in all caliciviruses. We demonstrate that the conserved stem-loop is essential for MNV viability. Mutant MNV RNAs with substitutions in the stem-loop replicated poorly until they accumulated mutations that revert to restore the stem-loop sequence and/or structure. The stem-loop sequence functions in a noncoding context, as it was possible to restore the replication of an MNV mutant by introducing an additional copy of the stem-loop between the NS7- and VP1-coding regions. Finally, in vitro biochemical data suggest that the stem-loop sequence is sufficient for the initiation of viral RNA synthesis by the recombinant MNV RNA-dependent RNA polymerase, confirming that the stem-loop forms the core of the norovirus subgenomic promoter. Noroviruses are a significant cause of viral gastroenteritis, and it is important to understand the mechanism of norovirus RNA synthesis. Here we describe the identification of an RNA stem-loop structure that functions as the core of the norovirus subgenomic RNA promoter in cells and in vitro. This work provides new insights into the molecular mechanisms of norovirus RNA synthesis and the sequences that determine the recognition of viral RNA by the RNA-dependent RNA polymerase. Copyright © 2015, American Society for Microbiology. All Rights

  11. SARS coronavirus protein 7a interacts with human Ap4A-hydrolase.

    PubMed

    Vasilenko, Natalia; Moshynskyy, Igor; Zakhartchouk, Alexander

    2010-02-09

    The SARS coronavirus (SARS-CoV) open reading frame 7a (ORF 7a) encodes a 122 amino acid accessory protein. It has no significant sequence homology with any other known proteins. The 7a protein is present in the virus particle and has been shown to interact with several host proteins; thereby implicating it as being involved in several pathogenic processes including apoptosis, inhibition of cellular protein synthesis, and activation of p38 mitogen activated protein kinase. In this study we present data demonstrating that the SARS-CoV 7a protein interacts with human Ap4A-hydrolase (asymmetrical diadenosine tetraphosphate hydrolase, EC 3.6.1.17). Ap4A-hydrolase is responsible for metabolizing the "allarmone" nucleotide Ap4A and therefore likely involved in regulation of cell proliferation, DNA replication, RNA processing, apoptosis and DNA repair. The interaction between 7a and Ap4A-hydrolase was identified using yeast two-hybrid screening. The interaction was confirmed by co-immunoprecipitation from cultured human cells transiently expressing V5-His tagged 7a and HA tagged Ap4A-hydrolase. Human tissue culture cells transiently expressing 7a and Ap4A-hydrolase tagged with EGFP and Ds-Red2 respectively show these proteins co-localize in the cytoplasm.

  12. RNA SYNTHESIS IN THE MOUSE OOCYTE

    PubMed Central

    Moore, G. P. M.; Lintern-Moore, Sue; Peters, Hannah; Faber, M.

    1974-01-01

    RNA synthesis in the oocyte and granulosa cell nuclei of growing follicles has been studied in the mouse ovary. The RNA precursor [3H]uridine was administered intraperitoneally to adult mice and the amount of label incorporated into ovarian RNA was quantitated autoradiographically using grain-counting procedures. Uridine incorporation into the nucleus is low in oocytes of small, resting follicles but increases during follicle growth and reaches a peak prior to the beginning of antrum formation. Thereafter uptake rapidly declines and is very low in the oocytes of maturing follicles. Uridine incorporation into granulosa cell nuclei, in contrast to that found in the oocyte, increases gradually during most of the period of follicle growth. Qualitative studies of the activity of endogenous, DNA-dependent RNA polymerases have also been made in fixed oocytes isolated from follicles at different stages of growth. Polymerase activity is demonstrable in the nucleolus and nucleoplasm of oocytes from growing follicles, but is absent from maturing oocytes of large follicles. PMID:4813213

  13. Molecular pathology of emerging coronavirus infections

    PubMed Central

    Gralinski, Lisa E; Baric, Ralph S

    2015-01-01

    Respiratory viruses can cause a wide spectrum of pulmonary diseases, ranging from mild, upper respiratory tract infections to severe and life-threatening lower respiratory tract infections, including the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Viral clearance and subsequent recovery from infection require activation of an effective host immune response; however, many immune effector cells may also cause injury to host tissues. Severe acute respiratory syndrome (SARS) coronavirus and Middle East respiratory syndrome (MERS) coronavirus cause severe infection of the lower respiratory tract, with 10% and 35% overall mortality rates, respectively; however, >50% mortality rates are seen in the aged and immunosuppressed populations. While these viruses are susceptible to interferon treatment in vitro, they both encode numerous genes that allow for successful evasion of the host immune system until after high virus titres have been achieved. In this review, we discuss the importance of the innate immune response and the development of lung pathology following human coronavirus infection. PMID:25270030

  14. Increased sensitivity to protein synthesis inhibitors in cells lacking tmRNA.

    PubMed Central

    de la Cruz, J; Vioque, A

    2001-01-01

    tmRNA (also known as SsrA or 10Sa RNA) is involved in a trans-translation reaction that contributes to the recycling of stalled ribosomes at the 3' end of an mRNA lacking a stop codon or at an internal mRNA cluster of rare codons. Inactivation of the ssrA gene in most bacteria results in viable cells bearing subtle phenotypes, such as temperature-sensitive growth. Herein, we report on the functional characterization of the ssrA gene in the cyanobacterium Synechocystis sp. strain PCC6803. Deletion of the ssrA gene in Synechocystis resulted in viable cells with a growth rate identical to wild-type cells. However, null ssrA cells (deltassrA) were not viable in the presence of the protein synthesis inhibitors chloramphenicol, lincomycin, spiramycin, tylosin, erythromycin, and spectinomycin at low doses that do not significantly affect the growth of wild-type cells. Sensitivity of deltassrA cells similar to wild-type cells was observed with kasugamycin, fusidic acid, thiostrepton, and puromycin. Antibiotics unrelated to protein synthesis, such as ampicillin or rifampicin, had no differential effect on the deltassrA strain. Furthermore, deletion of the ssrA gene is sufficient to impair global protein synthesis when chloramphenicol is added at sublethal concentrations for the wild-type strain. These results indicate that ribosomes stalled by some protein synthesis inhibitors can be recycled by tmRNA. In addition, this suggests that the first elongation cycle with tmRNA, which incorporates a noncoded alanine on the growing peptide chain, may have mechanistic differences with the normal elongation cycles that bypasses the block produced by these specific antibiotics. tmRNA inactivation could be an useful therapeutic target to increase the sensitivity of pathogenic bacteria against antibiotics. PMID:11780628

  15. Structural and Functional Analyses of the Severe Acute Respiratory Syndrome Coronavirus Endoribonuclease Nsp15

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhardwaj, Kanchan; Palaninathan, Satheesh; Alcantara, Joanna Maria Ortiz

    2008-03-31

    The severe acute respiratory syndrome (SARS) coronavirus encodes several RNA-processing enzymes that are unusual for RNA viruses, including Nsp15 (nonstructural protein 15), a hexameric endoribonuclease that preferentially cleaves 3' of uridines. We solved the structure of a catalytically inactive mutant version of Nsp15, which was crystallized as a hexamer. The structure contains unreported flexibility in the active site of each subunit. Substitutions in the active site residues serine 293 and proline 343 allowed Nsp15 to cleave at cytidylate, whereas mutation of leucine 345 rendered Nsp15 able to cleave at purines as well as pyrimidines. Mutations that targeted the residues involvedmore » in subunit interactions generally resulted in the formation of catalytically inactive monomers. The RNA-binding residues were mapped by a method linking reversible cross-linking, RNA affinity purification, and peptide fingerprinting. Alanine substitution of several residues in the RNA-contacting portion of Nsp15 did not affect hexamer formation but decreased the affinity of RNA binding and reduced endonuclease activity. This suggests a model for Nsp15 hexamer interaction with RNA.« less

  16. In vitro synthesis of minus-strand RNA by an isolated cereal yellow dwarf virus RNA-dependent RNA polymerase requires VPg and a stem-loop structure at the 3' end of the virus RNA.

    PubMed

    Osman, Toba A M; Coutts, Robert H A; Buck, Kenneth W

    2006-11-01

    Cereal yellow dwarf virus (CYDV) RNA has a 5'-terminal genome-linked protein (VPg). We have expressed the VPg region of the CYDV genome in bacteria and used the purified protein (bVPg) to raise an antiserum which was able to detect free VPg in extracts of CYDV-infected oat plants. A template-dependent RNA-dependent RNA polymerase (RdRp) has been produced from a CYDV membrane-bound RNA polymerase by treatment with BAL 31 nuclease. The RdRp was template specific, being able to utilize templates from CYDV plus- and minus-strand RNAs but not those of three unrelated viruses, Red clover necrotic mosaic virus, Cucumber mosaic virus, and Tobacco mosaic virus. RNA synthesis catalyzed by the RdRp required a 3'-terminal GU sequence and the presence of bVPg. Additionally, synthesis of minus-strand RNA on a plus-strand RNA template required the presence of a putative stem-loop structure near the 3' terminus of CYDV RNA. The base-paired stem, a single-nucleotide (A) bulge in the stem, and the sequence of a tetraloop were all required for the template activity. Evidence was produced showing that minus-strand synthesis in vitro was initiated by priming by bVPg at the 3' end of the template. The data are consistent with a model in which the RdRp binds to the stem-loop structure which positions the active site to recognize the 3'-terminal GU sequence for initiation of RNA synthesis by the addition of an A residue to VPg.

  17. Tethering of human Ago proteins to mRNA mimics the miRNA-mediated repression of protein synthesis.

    PubMed

    Pillai, Ramesh S; Artus, Caroline G; Filipowicz, Witold

    2004-10-01

    MicroRNAs (miRNAs) are approximately 21-nt-long RNAs involved in regulating development, differentiation, and other processes in eukaryotes. In metazoa, nearly all miRNAs control gene expression by imperfectly base-pairing with the 3'-untranslated region (3'-UTR) of target mRNAs and repressing protein synthesis by an unknown mechanism. It is also unknown whether miRNA-mRNA duplexes containing mismatches and bulges provide specific features that are recognized by factors mediating the repression. miRNAs form part of ribonucleoprotein complexes, miRNPs, that contain Argonaute (Ago) and other proteins. Here we demonstrate that effects of miRNAs on translation can be mimicked in human HeLa cells by the miRNA-independent tethering of Ago proteins to the 3'-UTR of a reporter mRNA. Inhibition of protein synthesis occurred without a change in the reporter mRNA level and was dependent on the number, but not the position, of the hairpins tethering hAgo2 to the 3'-UTR. These findings indicate that a primary function of miRNAs is to guide their associated proteins to the mRNA. Copyright 2004 RNA Society

  18. Isolation and Characterization of Dromedary Camel Coronavirus UAE-HKU23 from Dromedaries of the Middle East: Minimal Serological Cross-Reactivity between MERS Coronavirus and Dromedary Camel Coronavirus UAE-HKU23

    PubMed Central

    Woo, Patrick C. Y.; Lau, Susanna K. P.; Fan, Rachel Y. Y.; Lau, Candy C. Y.; Wong, Emily Y. M.; Joseph, Sunitha; Tsang, Alan K. L.; Wernery, Renate; Yip, Cyril C. Y.; Tsang, Chi-Ching; Wernery, Ulrich; Yuen, Kwok-Yung

    2016-01-01

    Recently, we reported the discovery of a dromedary camel coronavirus UAE-HKU23 (DcCoV UAE-HKU23) from dromedaries in the Middle East. In this study, DcCoV UAE-HKU23 was successfully isolated in two of the 14 dromedary fecal samples using HRT-18G cells, with cytopathic effects observed five days after inoculation. Northern blot analysis revealed at least seven distinct RNA species, corresponding to predicted subgenomic mRNAs and confirming the core sequence of transcription regulatory sequence motifs as 5′-UCUAAAC-3′ as we predicted previously. Antibodies against DcCoV UAE-HKU23 were detected in 58 (98.3%) and 59 (100%) of the 59 dromedary sera by immunofluorescence and neutralization antibody tests, respectively. There was significant correlation between the antibody titers determined by immunofluorescence and neutralization assays (Pearson coefficient = 0.525, p < 0.0001). Immunization of mice using recombinant N proteins of DcCoV UAE-HKU23 and Middle East respiratory syndrome coronavirus (MERS-CoV), respectively, and heat-inactivated DcCoV UAE-HKU23 showed minimal cross-antigenicity between DcCoV UAE-HKU23 and MERS-CoV by Western blot and neutralization antibody assays. Codon usage and genetic distance analysis of RdRp, S and N genes showed that the 14 strains of DcCoV UAE-HKU23 formed a distinct cluster, separated from those of other closely related members of Betacoronavirus 1, including alpaca CoV, confirming that DcCoV UAE-HKU23 is a novel member of Betacoronavirus 1. PMID:27164099

  19. Crystal structure of mouse coronavirus receptor-binding domain complexed with its murine receptor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Peng, Guiqing; Sun, Dawei; Rajashankar, Kanagalaghatta R.

    2011-09-28

    Coronaviruses have evolved diverse mechanisms to recognize different receptors for their cross-species transmission and host-range expansion. Mouse hepatitis coronavirus (MHV) uses the N-terminal domain (NTD) of its spike protein as its receptor-binding domain. Here we present the crystal structure of MHV NTD complexed with its receptor murine carcinoembryonic antigen-related cell adhesion molecule 1a (mCEACAM1a). Unexpectedly, MHV NTD contains a core structure that has the same {beta}-sandwich fold as human galectins (S-lectins) and additional structural motifs that bind to the N-terminal Ig-like domain of mCEACAM1a. Despite its galectin fold, MHV NTD does not bind sugars, but instead binds mCEACAM1a through exclusivemore » protein-protein interactions. Critical contacts at the interface have been confirmed by mutagenesis, providing a structural basis for viral and host specificities of coronavirus/CEACAM1 interactions. Sugar-binding assays reveal that galectin-like NTDs of some coronaviruses such as human coronavirus OC43 and bovine coronavirus bind sugars. Structural analysis and mutagenesis localize the sugar-binding site in coronavirus NTDs to be above the {beta}-sandwich core. We propose that coronavirus NTDs originated from a host galectin and retained sugar-binding functions in some contemporary coronaviruses, but evolved new structural features in MHV for mCEACAM1a binding.« less

  20. Competitive fitness in coronaviruses is not correlated with size or number of double-membrane vesicles under reduced-temperature growth conditions.

    PubMed

    Al-Mulla, Hawaa M N; Turrell, Lauren; Smith, Nicola M; Payne, Luke; Baliji, Surendranath; Züst, Roland; Thiel, Volker; Baker, Susan C; Siddell, Stuart G; Neuman, Benjamin W

    2014-04-01

    Positive-stranded viruses synthesize their RNA in membrane-bound organelles, but it is not clear how this benefits the virus or the host. For coronaviruses, these organelles take the form of double-membrane vesicles (DMVs) interconnected by a convoluted membrane network. We used electron microscopy to identify murine coronaviruses with mutations in nsp3 and nsp14 that replicated normally while producing only half the normal amount of DMVs under low-temperature growth conditions. Viruses with mutations in nsp5 and nsp16 produced small DMVs but also replicated normally. Quantitative reverse transcriptase PCR (RT-PCR) confirmed that the most strongly affected of these, the nsp3 mutant, produced more viral RNA than wild-type virus. Competitive growth assays were carried out in both continuous and primary cells to better understand the contribution of DMVs to viral fitness. Surprisingly, several viruses that produced fewer or smaller DMVs showed a higher fitness than wild-type virus at the reduced temperature, suggesting that larger and more numerous DMVs do not necessarily confer a competitive advantage in primary or continuous cell culture. For the first time, this directly demonstrates that replication and organelle formation may be, at least in part, studied separately during infection with positive-stranded RNA virus. IMPORTANCE The viruses that cause severe acute respiratory syndrome (SARS), poliomyelitis, and hepatitis C all replicate in double-membrane vesicles (DMVs). The big question about DMVs is why they exist in the first place. In this study, we looked at thousands of infected cells and identified two coronavirus mutants that made half as many organelles as normal and two others that made typical numbers but smaller organelles. Despite differences in DMV size and number, all four mutants replicated as efficiently as wild-type virus. To better understand the relative importance of replicative organelles, we carried out competitive fitness experiments. None

  1. The C-Terminal Tail of TRIM56 Dictates Antiviral Restriction of Influenza A and B Viruses by Impeding Viral RNA Synthesis

    PubMed Central

    Liu, Baoming; Li, Nan L.; Shen, Yang; Bao, Xiaoyong; Elbahesh, Husni; Webby, Richard J.

    2016-01-01

    ABSTRACT Accumulating data suggest that tripartite-motif-containing (TRIM) proteins participate in host responses to viral infections, either by acting as direct antiviral restriction factors or through regulating innate immune signaling of the host. Of >70 TRIMs, TRIM56 is a restriction factor of several positive-strand RNA viruses, including three members of the family Flaviviridae (yellow fever virus, dengue virus, and bovine viral diarrhea virus) and a human coronavirus (OC43), and this ability invariably depends upon the E3 ligase activity of TRIM56. However, the impact of TRIM56 on negative-strand RNA viruses remains unclear. Here, we show that TRIM56 puts a check on replication of influenza A and B viruses in cell culture but does not inhibit Sendai virus or human metapneumovirus, two paramyxoviruses. Interestingly, the anti-influenza virus activity was independent of the E3 ligase activity, B-box, or coiled-coil domain. Rather, deletion of a 63-residue-long C-terminal-tail portion of TRIM56 abrogated the antiviral function. Moreover, expression of this short C-terminal segment curtailed the replication of influenza viruses as effectively as that of full-length TRIM56. Mechanistically, TRIM56 was found to specifically impede intracellular influenza virus RNA synthesis. Together, these data reveal a novel antiviral activity of TRIM56 against influenza A and B viruses and provide insights into the mechanism by which TRIM56 restricts these medically important orthomyxoviruses. IMPORTANCE Options to treat influenza are limited, and drug-resistant influenza virus strains can emerge through minor genetic changes. Understanding novel virus-host interactions that alter influenza virus fitness may reveal new targets/approaches for therapeutic interventions. We show here that TRIM56, a tripartite-motif protein, is an intrinsic host restriction factor of influenza A and B viruses. Unlike its antiviral actions against positive-strand RNA viruses, the anti

  2. Studies on the Role of RNA Synthesis in Auxin Induction of Cell Enlargement 1

    PubMed Central

    Nooden, Larry D.

    1968-01-01

    Selective inhibitors were used to study the connection between nucleic acid synthesis and indoleacetic acid (IAA) induction of cell enlargement. Actinomycin D (act D) and azaguanine (azaG) almost completely inhibit IAA-induced growth in aged artichoke tuber disks when they are added simultaneously with IAA. In contrast, when they are added 24 hours after the hormone, these inhibitors have little or no effect on the induced growth which continues for 48 hours or more with little or no inhibition. Inhibitors of protein synthesis still stop growth when applied 24 hours after the IAA, thus protein synthesis and presumably supporting metabolism are still essential. In corn coleoptile sections auxin-induced growth did not show any pronounced tendency to become less sensitive to act D as the IAA treatment progressed. Act D did not completely inhibit the response to IAA unless the sections were pretreated with act D for 6 hours. In contrast to act D, cordycepin produced almost complete inhibition of IAA-induced growth when added with the IAA. Although IAA has a very large and very rapid stimulatory effect (within 10 min) on incorporation of 32P-orthophosphate into RNA in disks, it did not cause a detectable change in the base composition of the RNA synthesized. Furthermore, the promotive effect could be accounted for through increased uptake of the 32P. That much of the RNA synthesis in these tissues is not necessary for auxin action is indicated by the results with fluorouracil (FU). FU strongly inhibits RNA synthesis, probably acting preferentially on ribosomal RNA synthesis, without inhibiting auxin-induced growth in the disks or coleoptile sections. FU also strongly inhibited respiration in auxin-treated disks indicating that the large promotion of respiration by auxin likewise may not be entirely necessary for growth. At least in the artichoke disks, RNA synthesis is required for auxin induction of cell enlargement and not for cell enlargement itself. The possible

  3. Synthesis and properties of 2'-O-methyl-4'-thioRNA.

    PubMed

    Takahashi, Mayumi; Inoue, Naonori; Minakawa, Noriaki; Matsuda, Akira

    2005-01-01

    In this presentation, we will discuss the synthesis and properties of 2'-O-methyl-4'-thioRNA, an RNA molecule consisting of 2'-O-methyl-4'-thionucleosides. We first synthesized 2'-O-methyl-4'-thiouridine and -cytidine derivatives via 2,2'-O-anhydro-4'-thiouridine. The RNA consisting of 2'-O-methyl-4'-thiopyrimidine nucleosides and 2'-O-methylpurine nucleosides, 2'-OMe-4'-thioRNA, was synthesized on a DNA synthesizer according to the standard phosphoramidite protocol.

  4. Antibody response to equine coronavirus in horses inoculated with a bovine coronavirus vaccine.

    PubMed

    Nemoto, Manabu; Kanno, Toru; Bannai, Hiroshi; Tsujimura, Koji; Yamanaka, Takashi; Kokado, Hiroshi

    2017-11-17

    A vaccine for equine coronavirus (ECoV) is so far unavailable. Bovine coronavirus (BCoV) is antigenically related to ECoV; it is therefore possible that BCoV vaccine will induce antibodies against ECoV in horses. This study investigated antibody response to ECoV in horses inoculated with BCoV vaccine. Virus neutralization tests showed that antibody titers against ECoV increased in all six horses tested at 14 days post inoculation, although the antibody titers were lower against ECoV than against BCoV. This study showed that BCoV vaccine provides horses with antibodies against ECoV to some extent. It is unclear whether antibodies provided by BCoV vaccine are effective against ECoV, and therefore ECoV challenge studies are needed to evaluate efficacy of the vaccine in the future.

  5. Akt activation enhances ribosomal RNA synthesis through casein kinase II and TIF-IA.

    PubMed

    Nguyen, Le Xuan Truong; Mitchell, Beverly S

    2013-12-17

    Transcription initiation factor I (TIF-IA) plays an essential role in regulating ribosomal RNA (rRNA) synthesis by tethering RNA polymerase I (Pol I) to the rDNA promoter. We have found that activated Akt enhances rRNA synthesis through the phosphorylation of casein kinase IIα (CK2α) on a threonine residue near its N terminus. CK2 in turn phosphorylates TIF-IA, thereby increasing rDNA transcription. Activated Akt also stabilizes TIF-IA, induces its translocation to the nucleolus, and enhances its interaction with Pol I. Treatment with AZD8055, an inhibitor of both Akt and mammalian target of rapamycin phosphorylation, but not with rapamycin, disrupts Akt-mediated TIF-IA stability, translocation, and activity. These data support a model in which activated Akt enhances rRNA synthesis both by preventing TIF-IA degradation and phosphorylating CK2α, which in turn phosphorylates TIF-IA. This model provides an explanation for the ability of activated Akt to promote cell proliferation and, potentially, transformation.

  6. Genetic diversity of coronaviruses in bats in Lao PDR and Cambodia.

    PubMed

    Lacroix, Audrey; Duong, Veasna; Hul, Vibol; San, Sorn; Davun, Hull; Omaliss, Keo; Chea, Sokha; Hassanin, Alexandre; Theppangna, Watthana; Silithammavong, Soubanh; Khammavong, Kongsy; Singhalath, Sinpakone; Greatorex, Zoe; Fine, Amanda E; Goldstein, Tracey; Olson, Sarah; Joly, Damien O; Keatts, Lucy; Dussart, Philippe; Afelt, Aneta; Frutos, Roger; Buchy, Philippe

    2017-03-01

    South-East Asia is a hot spot for emerging zoonotic diseases, and bats have been recognized as hosts for a large number of zoonotic viruses such as Severe Acute Respiratory Syndrome (SARS), responsible for acute respiratory syndrome outbreaks. Thus, it is important to expand our knowledge of the presence of viruses in bats which could represent a risk to humans. Coronaviruses (CoVs) have been reported in bat species from Thailand, China, Indonesia, Taiwan and the Philippines. However no such work was conducted in Cambodia or Lao PDR. Between 2010 and 2013, 1965 bats were therefore sampled at interfaces with human populations in these two countries. They were tested for the presence of coronavirus by consensus reverse transcription-PCR assay. A total of 93 samples (4.7%) from 17 genera of bats tested positive. Sequence analysis revealed the presence of potentially 37 and 56 coronavirus belonging to alpha-coronavirus (αCoV) and beta-CoV (βCoV), respectively. The βCoVs group is known to include some coronaviruses highly pathogenic to human, such as SARS-CoV and MERS-CoV. All coronavirus sequences generated from frugivorous bats (family Pteropodidae) (n=55) clustered with other bat βCoVs of lineage D, whereas one coronavirus from Pipistrellus coromandra fell in the lineage C of βCoVs which also includes the MERS-CoV. αCoVs were all detected in various genera of insectivorous bats and clustered with diverse bat αCoV sequences previously published. A closely related strain of PEDV, responsible for severe diarrhea in pigs (PEDV-CoV), was detected in 2 Myotis bats. We highlighted the presence and the high diversity of coronaviruses circulating in bats from Cambodia and Lao PDR. Three new bat genera and species were newly identified as host of coronaviruses, namely Macroglossus sp., Megaerops niphanae and Myotis horsfieldii. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses.

    PubMed

    Hilgenfeld, Rolf; Peiris, Malik

    2013-10-01

    This article introduces a series of invited papers in Antiviral Research marking the 10th anniversary of the outbreak of severe acute respiratory syndrome (SARS), caused by a novel coronavirus that emerged in southern China in late 2002. Until that time, coronaviruses had not been recognized as agents causing severe disease in humans, hence, the emergence of the SARS-CoV came as a complete surprise. Research during the past ten years has revealed the existence of a diverse pool of coronaviruses circulating among various bat species and other animals, suggesting that further introductions of highly pathogenic coronaviruses into the human population are not merely probable, but inevitable. The recent emergence of another coronavirus causing severe disease, Middle East respiratory syndrome (MERS), in humans, has made it clear that coronaviruses pose a major threat to human health, and that more research is urgently needed to elucidate their replication mechanisms, identify potential drug targets, and develop effective countermeasures. In this series, experts in many different aspects of coronavirus replication and disease will provide authoritative, up-to-date reviews of the following topics: - clinical management and infection control of SARS; - reservoir hosts of coronaviruses; - receptor recognition and cross-species transmission of SARS-CoV; - SARS-CoV evasion of innate immune responses; - structures and functions of individual coronaviral proteins; - anti-coronavirus drug discovery and development; and - the public health legacy of the SARS outbreak. Each article will be identified in the last line of its abstract as belonging to the series "From SARS to MERS: 10years of research on highly pathogenic human coronaviruses." Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Reverse genetics with a full-length infectious cDNA of the Middle East respiratory syndrome coronavirus.

    PubMed

    Scobey, Trevor; Yount, Boyd L; Sims, Amy C; Donaldson, Eric F; Agnihothram, Sudhakar S; Menachery, Vineet D; Graham, Rachel L; Swanstrom, Jesica; Bove, Peter F; Kim, Jeeho D; Grego, Sonia; Randell, Scott H; Baric, Ralph S

    2013-10-01

    Severe acute respiratory syndrome with high mortality rates (~50%) is associated with a novel group 2c betacoronavirus designated Middle East respiratory syndrome coronavirus (MERS-CoV). We synthesized a panel of contiguous cDNAs that spanned the entire genome. Following contig assembly into genome-length cDNA, transfected full-length transcripts recovered several recombinant viruses (rMERS-CoV) that contained the expected marker mutations inserted into the component clones. Because the wild-type MERS-CoV contains a tissue culture-adapted T1015N mutation in the S glycoprotein, rMERS-CoV replicated ~0.5 log less efficiently than wild-type virus. In addition, we ablated expression of the accessory protein ORF5 (rMERS•ORF5) and replaced it with tomato red fluorescent protein (rMERS-RFP) or deleted the entire ORF3, 4, and 5 accessory cluster (rMERS-ΔORF3-5). Recombinant rMERS-CoV, rMERS-CoV•ORF5, and MERS-CoV-RFP replicated to high titers, whereas MERS-ΔORF3-5 showed 1-1.5 logs reduced titer compared with rMERS-CoV. Northern blot analyses confirmed the associated molecular changes in the recombinant viruses, and sequence analysis demonstrated that RFP was expressed from the appropriate consensus sequence AACGAA. We further show dipeptidyl peptidase 4 expression, MERS-CoV replication, and RNA and protein synthesis in human airway epithelial cell cultures, primary lung fibroblasts, primary lung microvascular endothelial cells, and primary alveolar type II pneumocytes, demonstrating a much broader tissue tropism than severe acute respiratory syndrome coronavirus. The availability of a MERS-CoV molecular clone, as well as recombinant viruses expressing indicator proteins, will allow for high-throughput testing of therapeutic compounds and provide a genetic platform for studying gene function and the rational design of live virus vaccines.

  9. Regulation of early mRNA synthesis after bacteriophage T4 infection of Escherichia coli.

    PubMed Central

    Linder, C H; Fast, R

    1975-01-01

    Regulation of T4-specific mRNA synthesis was studied during leucine starvation of a leucine-requiring stringent Escherichia coli B strain. This was done by imposing starvation prior to T4 infection and then letting RNA synthesis proceed for different time periods. Rifampin or streptolydigin was added to stop further RNA synthesis, and protein synthesis was restored by addition of leucine. Samples were withdrawn at different times, and the enzyme-forming capacities found that, during conditions which elicit the stringent response in uninfected bacteria, immediate early mRNA is not stringently regulated. This conclusion contradicts the earlier conclusion of others, obtained by measuring incorporation of radioactive uracil; this is explained by the observation of Edlin and Neuhard (1967), confirmed and extended by us to the T4-infected cell, that the incorporation of uracil into RNA of a stringent strain is virtually blocked by amino acid starvation, whereas that of adenine continues at 30 to 50% of the rate seen in the presence of the required amino acid. PMID:1099229

  10. Improved deoxyribozymes for synthesis of covalently branched DNA and RNA.

    PubMed

    Lee, Christine S; Mui, Timothy P; Silverman, Scott K

    2011-01-01

    A covalently branched nucleic acid can be synthesized by joining the 2'-hydroxyl of the branch-site ribonucleotide of a DNA or RNA strand to the activated 5'-phosphorus of a separate DNA or RNA strand. We have previously used deoxyribozymes to synthesize several types of branched nucleic acids for experiments in biotechnology and biochemistry. Here, we report in vitro selection experiments to identify improved deoxyribozymes for synthesis of branched DNA and RNA. Each of the new deoxyribozymes requires Mn²(+) as a cofactor, rather than Mg²(+) as used by our previous branch-forming deoxyribozymes, and each has an initially random region of 40 rather than 22 or fewer combined nucleotides. The deoxyribozymes all function by forming a three-helix-junction (3HJ) complex with their two oligonucleotide substrates. For synthesis of branched DNA, the best new deoxyribozyme, 8LV13, has k(obs) on the order of 0.1 min⁻¹, which is about two orders of magnitude faster than our previously identified 15HA9 deoxyribozyme. 8LV13 also functions at closer-to-neutral pH than does 15HA9 (pH 7.5 versus 9.0) and has useful tolerance for many DNA substrate sequences. For synthesis of branched RNA, two new deoxyribozymes, 8LX1 and 8LX6, were identified with broad sequence tolerances and substantial activity at pH 7.5, versus pH 9.0 for many of our previous deoxyribozymes that form branched RNA. These experiments provide new, and in key aspects improved, practical catalysts for preparation of synthetic branched DNA and RNA.

  11. Detection of feline coronavirus using microcantilever sensors

    NASA Astrophysics Data System (ADS)

    Velanki, Sreepriya; Ji, Hai-Feng

    2006-11-01

    This work demonstrated the feasibility of detecting severe acute respiratory syndrome associated coronavirus (SARS-CoV) using microcantilever technology by showing that the feline coronavirus (FIP) type I virus can be detected by a microcantilever modified by feline coronavirus (FIP) type I anti-viral antiserum. A microcantilever modified by FIP type I anti-viral antiserum was developed for the detection of FIP type I virus. When the FIP type I virus positive sample is injected into the fluid cell where the microcantilever is held, the microcantilever bends upon the recognition of the FIP type I virus by the antiserum on the surface of the microcantilever. A negative control sample that does not contain FIP type I virus did not cause any bending of the microcantilever. The detection limit of the sensor was 0.1 µg ml-1 when the assay time was <1 h.

  12. Bioinformatics and functional analyses of coronavirus nonstructural proteins involved in the formation of replicative organelles.

    PubMed

    Neuman, Benjamin W

    2016-11-01

    Replication of eukaryotic positive-stranded RNA viruses is usually linked to the presence of membrane-associated replicative organelles. The purpose of this review is to discuss the function of proteins responsible for formation of the coronavirus replicative organelle. This will be done by identifying domains that are conserved across the order Nidovirales, and by summarizing what is known about function and structure at the level of protein domains. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Antibody response to equine coronavirus in horses inoculated with a bovine coronavirus vaccine

    PubMed Central

    NEMOTO, Manabu; KANNO, Toru; BANNAI, Hiroshi; TSUJIMURA, Koji; YAMANAKA, Takashi; KOKADO, Hiroshi

    2017-01-01

    A vaccine for equine coronavirus (ECoV) is so far unavailable. Bovine coronavirus (BCoV) is antigenically related to ECoV; it is therefore possible that BCoV vaccine will induce antibodies against ECoV in horses. This study investigated antibody response to ECoV in horses inoculated with BCoV vaccine. Virus neutralization tests showed that antibody titers against ECoV increased in all six horses tested at 14 days post inoculation, although the antibody titers were lower against ECoV than against BCoV. This study showed that BCoV vaccine provides horses with antibodies against ECoV to some extent. It is unclear whether antibodies provided by BCoV vaccine are effective against ECoV, and therefore ECoV challenge studies are needed to evaluate efficacy of the vaccine in the future. PMID:28993568

  14. RNA-primed complementary-sense DNA synthesis of the geminivirus African cassava mosaic virus.

    PubMed Central

    Saunders, K; Lucy, A; Stanley, J

    1992-01-01

    The plant DNA virus African cassava mosaic virus (ACMV) is believed to replicate by a rolling circle mechanism. To investigate complementary-sense DNA (lagging strand) synthesis, we have analysed the heterogenous form of complementary-sense DNA (H3 DNA) from infected Nicotiana benthamiana by two-dimensional agarose gel electrophoresis and blot hybridisation. The presence of an RNA moeity is demonstrated by comparison of results for nucleic acids resolved on neutral/alkaline and neutral/formamide gels, suggesting that complementary-sense DNA synthesis on the virus-sense single-stranded DNA template is preceded by the synthesis of an RNA primer. Hybridisation with probes to specific parts of ACMV DNA A genome indicates that synthesis of the putative RNA primer initiates between nucleotides 2581-221, a region that includes intergenic sequences that have been implicated in geminivirus DNA replication and the control of gene expression. Images PMID:1475192

  15. Interaction of TIF-90 and filamin A in the regulation of rRNA synthesis in leukemic cells.

    PubMed

    Nguyen, Le Xuan Truong; Chan, Steven M; Ngo, Tri Duc; Raval, Aparna; Kim, Kyeong Kyu; Majeti, Ravindra; Mitchell, Beverly S

    2014-07-24

    The transcription initiation factor I (TIF-IA) is an important regulator of the synthesis of ribosomal RNA (rRNA) through its facilitation of the recruitment of RNA polymerase I (Pol I) to the ribosomal DNA promoter. Activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway, which occurs commonly in acute myelogenous leukemia, enhances rRNA synthesis through TIF-IA stabilization and phosphorylation. We have discovered that TIF-IA coexists with a splicing isoform, TIF-90, which is expressed preferentially in the nucleolus and at higher levels in proliferating and transformed hematopoietic cells. TIF-90 interacts directly with Pol I to increase rRNA synthesis as a consequence of Akt activation. Furthermore, TIF-90 binds preferentially to a 90-kDa cleavage product of the actin binding protein filamin A (FLNA) that inhibits rRNA synthesis. Increased expression of TIF-90 overcomes the inhibitory effect of this cleavage product and stimulates rRNA synthesis. Because activated Akt also reduces FLNA cleavage, these results indicate that activated Akt and TIF-90 function in parallel to increase rRNA synthesis and, as a consequence, cell proliferation in leukemic cells. These results provide evidence that the direct targeting of Akt would be an effective therapy in acute leukemias in which Akt is activated. © 2014 by The American Society of Hematology.

  16. Gene activity during germination of spores of the fern, Onoclea sensibilis: RNA and protein synthesis and the role of stored mRNA

    NASA Technical Reports Server (NTRS)

    Raghavan, V.

    1991-01-01

    Pattern of 3H-uridine incorporation into RNA of spores of Onoclea sensibilis imbibed in complete darkness (non-germinating conditions) and induced to germinate in red light was followed by oligo-dT cellulose chromatography, gel electrophoresis coupled with fluorography and autoradiography. In dark-imbibed spores, RNA synthesis was initiated about 24 h after sowing, with most of the label accumulating in the high mol. wt. poly(A) -RNA fraction. There was no incorporation of the label into poly(A) +RNA until 48 h after sowing. In contrast, photo-induced spores began to synthesize all fractions of RNA within 12 h after sowing and by 24 h, incorporation of 3H-uridine into RNA of irradiated spores was nearly 70-fold higher than that into dark-imbibed spores. Protein synthesis, as monitored by 3H-arginine incorporation into the acid-insoluble fraction and by autoradiography, was initiated in spores within 1-2 h after sowing under both conditions. Autoradiographic experiments also showed that onset of protein synthesis in the cytoplasm of the germinating spore is independent of the transport of newly synthesized nuclear RNA. One-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis of 35S-methionine-labelled proteins revealed a good correspondence between proteins synthesized in a cell-free translation system directed by poly(A) +RNA of dormant spores and those synthesized in vivo by dark-imbibed and photo-induced spores. These results indicate that stored mRNAs of O. sensibilis spores are functionally competent and provide templates for the synthesis of proteins during dark-imbibition and germination.

  17. Evolution of Protein Synthesis from an RNA World

    PubMed Central

    Noller, Harry F.

    2012-01-01

    SUMMARY Because of the molecular complexity of the ribosome and protein synthesis, it is a challenge to imagine how translation could have evolved from a primitive RNA World. Two specific suggestions are made here to help to address this, involving separate evolution of the peptidyl transferase and decoding functions. First, it is proposed that translation originally arose not to synthesize functional proteins, but to provide simple (perhaps random) peptides that bound to RNA, increasing its available structure space, and therefore its functional capabilities. Second, it is proposed that the decoding site of the ribosome evolved from a mechanism for duplication of RNA. This process involved homodimeric “duplicator RNAs,” resembling the anticodon arms of tRNAs, which directed ligation of trinucleotides in response to an RNA template. PMID:20610545

  18. Development of a SARS Coronavirus Vaccine from Recombinant Spike Protein Plus Delta Inulin Adjuvant.

    PubMed

    McPherson, Clifton; Chubet, Richard; Holtz, Kathy; Honda-Okubo, Yoshikazu; Barnard, Dale; Cox, Manon; Petrovsky, Nikolai

    2016-01-01

    Given periodic outbreaks of fatal human infections caused by coronaviruses, development of an optimal coronavirus vaccine platform capable of rapid production is an ongoing priority. This chapter describes the use of an insect cell expression system for rapid production of a recombinant vaccine against severe acute respiratory syndrome coronavirus (SARS). Detailed methods are presented for expression, purification, and release testing of SARS recombinant spike protein antigen, followed by adjuvant formulation and animal testing. The methods herein described for rapid development of a highly protective SARS vaccine are equally suited to rapid development of vaccines against other fatal human coronavirus infections, e.g., the MERS coronavirus.

  19. Pathogenic characteristics of persistent feline enteric coronavirus infection in cats

    PubMed Central

    Vogel, Liesbeth; Van der Lubben, Mariken; Te Lintelo, Eddie G.; Bekker, Cornelis P.J.; Geerts, Tamara; Schuijff, Leontine S.; Grinwis, Guy C.M.; Egberink, Herman F.; Rottier, Peter J.M.

    2010-01-01

    Feline coronaviruses (FCoV) comprise two biotypes: feline enteric coronaviruses (FECV) and feline infectious peritonitis viruses (FIPV). FECV is associated with asymptomatic persistent enteric infections, while FIPV causes feline infectious peritonitis (FIP), a usually fatal systemic disease in domestic cats and some wild Felidae. FIPV arises from FECV by mutation. FCoV also occur in two serotypes, I and II, of which the serotype I viruses are by far the most prevalent in the field. Yet, most of our knowledge about FCoV infections relates to serotype II viruses, particularly about the FIPV, mainly because type I viruses grow poorly in cell culture. Hence, the aim of the present work was the detailed study of the epidemiologically most relevant viruses, the avirulent serotype I viruses. Kittens were inoculated oronasally with different doses of two independent FECV field strains, UCD and RM. Persistent infection could be reproducibly established. The patterns of clinical symptoms, faecal virus shedding and seroconversion were monitored for up to 10 weeks revealing subtle but reproducible differences between the two viruses. Faecal virus, i.e. genomic RNA, was detected during persistent FECV infection only in the large intestine, downstream of the appendix, and could occasionally be observed also in the blood. The implications of our results, particularly our insights into the persistently infected state, are discussed. PMID:20663472

  20. Identification and Characterization of a Novel Alpaca Respiratory Coronavirus Most Closely Related to the Human Coronavirus 229E

    PubMed Central

    Crossley, Beate M.; Mock, Richard E.; Callison, Scott A.; Hietala, Sharon K.

    2012-01-01

    In 2007, a novel coronavirus associated with an acute respiratory disease in alpacas (Alpaca Coronavirus, ACoV) was isolated. Full-length genomic sequencing of the ACoV demonstrated the genome to be consistent with other Alphacoronaviruses. A putative additional open-reading frame was identified between the nucleocapsid gene and 3'UTR. The ACoV was genetically most similar to the common human coronavirus (HCoV) 229E with 92.2% nucleotide identity over the entire genome. A comparison of spike gene sequences from ACoV and from HCoV-229E isolates recovered over a span of five decades showed the ACoV to be most similar to viruses isolated in the 1960’s to early 1980’s. The true origin of the ACoV is unknown, however a common ancestor between the ACoV and HCoV-229E appears to have existed prior to the 1960’s, suggesting virus transmission, either as a zoonosis or anthroponosis, has occurred between alpacas and humans. PMID:23235471

  1. Regulation of Viral RNA Synthesis by the V Protein of Parainfluenza Virus 5

    PubMed Central

    Yang, Yang; Zengel, James; Sun, Minghao; Sleeman, Katrina; Timani, Khalid Amine; Aligo, Jason; Rota, Paul

    2015-01-01

    ABSTRACT Paramyxoviruses include many important animal and human pathogens. The genome of parainfluenza virus 5 (PIV5), a prototypical paramyxovirus, encodes a V protein that inhibits viral RNA synthesis. In this work, the mechanism of inhibition was investigated. Using mutational analysis and a minigenome system, we identified regions in the N and C termini of the V protein that inhibit viral RNA synthesis: one at the very N terminus of V and the second at the C terminus of V. Furthermore, we determined that residues L16 and I17 are critical for the inhibitory function of the N-terminal region of the V protein. Both regions interact with the nucleocapsid protein (NP), an essential component of the viral RNA genome complex (RNP). Mutations at L16 and I17 abolished the interaction between NP and the N-terminal domain of V. This suggests that the interaction between NP and the N-terminal domain plays a critical role in V inhibition of viral RNA synthesis by the N-terminal domain. Both the N- and C-terminal regions inhibited viral RNA replication. The C terminus inhibited viral RNA transcription, while the N-terminal domain enhanced viral RNA transcription, suggesting that the two domains affect viral RNA through different mechanisms. Interestingly, V also inhibited the synthesis of the RNA of other paramyxoviruses, such as Nipah virus (NiV), human parainfluenza virus 3 (HPIV3), measles virus (MeV), mumps virus (MuV), and respiratory syncytial virus (RSV). This suggests that a common host factor may be involved in the replication of these paramyxoviruses. IMPORTANCE We identified two regions of the V protein that interact with NP and determined that one of these regions enhances viral RNA transcription via its interaction with NP. Our data suggest that a common host factor may be involved in the regulation of paramyxovirus replication and could be a target for broad antiviral drug development. Understanding the regulation of paramyxovirus replication will enable the

  2. Emergence of Pathogenic Coronaviruses in Cats by Homologous Recombination between Feline and Canine Coronaviruses

    PubMed Central

    Terada, Yutaka; Matsui, Nobutaka; Noguchi, Keita; Kuwata, Ryusei; Shimoda, Hiroshi; Soma, Takehisa; Mochizuki, Masami; Maeda, Ken

    2014-01-01

    Type II feline coronavirus (FCoV) emerged via double recombination between type I FCoV and type II canine coronavirus (CCoV). In this study, two type I FCoVs, three type II FCoVs and ten type II CCoVs were genetically compared. The results showed that three Japanese type II FCoVs, M91-267, KUK-H/L and Tokyo/cat/130627, also emerged by homologous recombination between type I FCoV and type II CCoV and their parent viruses were genetically different from one another. In addition, the 3′-terminal recombination sites of M91-267, KUK-H/L and Tokyo/cat/130627 were different from one another within the genes encoding membrane and spike proteins, and the 5′-terminal recombination sites were also located at different regions of ORF1. These results indicate that at least three Japanese type II FCoVs emerged independently. Sera from a cat experimentally infected with type I FCoV was unable to neutralize type II CCoV infection, indicating that cats persistently infected with type I FCoV may be superinfected with type II CCoV. Our previous study reported that few Japanese cats have antibody against type II FCoV. All of these observations suggest that type II FCoV emerged inside the cat body and is unable to readily spread among cats, indicating that these recombination events for emergence of pathogenic coronaviruses occur frequently. PMID:25180686

  3. Inhibition of Dengue Virus RNA Synthesis by an Adenosine Nucleoside ▿ †

    PubMed Central

    Chen, Yen-Liang; Yin, Zheng; Duraiswamy, Jeyaraj; Schul, Wouter; Lim, Chin Chin; Liu, Boping; Xu, Hao Ying; Qing, Min; Yip, Andy; Wang, Gang; Chan, Wai Ling; Tan, Hui Pen; Lo, Melissa; Liung, Sarah; Kondreddi, Ravinder Reddy; Rao, Ranga; Gu, Helen; He, Handan; Keller, Thomas H.; Shi, Pei-Yong

    2010-01-01

    We recently reported that (2R,3R,4R,5R)-2-(4-amino-pyrrolo[2,3-d]pyrimidin-7-yl)-3-ethynyl-5-hydroxy-methyl-tetrahydro-furan-3,4-diol is a potent inhibitor of dengue virus (DENV), with 50% effective concentration (EC50) and cytotoxic concentration (CC50) values of 0.7 μM and >100 μM, respectively. Here we describe the synthesis, structure-activity relationship, and antiviral characterization of the inhibitor. In an AG129 mouse model, a single-dose treatment of DENV-infected mice with the compound suppressed peak viremia and completely prevented death. Mode-of-action analysis using a DENV replicon indicated that the compound blocks viral RNA synthesis. Recombinant adenosine kinase could convert the compound to a monophosphate form. Suppression of host adenosine kinase, using a specific inhibitor (iodotubercidin) or small interfering RNA (siRNA), abolished or reduced the compound's antiviral activity in cell culture. Studies of rats showed that 14C-labeled compound was converted to mono-, di-, and triphosphate metabolites in vivo. Collectively, the results suggest that this adenosine inhibitor is phosphorylated to an active (triphosphate) form which functions as a chain terminator for viral RNA synthesis. PMID:20457821

  4. Interferon-β 1a and SARS Coronavirus Replication

    PubMed Central

    Hensley, Lisa E.; Fritz, Elizabeth A.; Karp, Christopher; Huggins, John W.; Geisbert, Thomas W.

    2004-01-01

    A global outbreak of severe acute respiratory syndrome (SARS) caused by a novel coronavirus began in March 2003. The rapid emergence of SARS and the substantial illness and death it caused have made it a critical public health issue. Because no effective treatments are available, an intensive effort is under way to identify and test promising antiviral drugs. Here, we report that recombinant human interferon (IFN)-β 1a potently inhibits SARS coronavirus replication in vitro. PMID:15030704

  5. Induction of vitellogenin synthesis by estrogen in avian liver: relationship between level of vitellogenin mRNA and vitellogenin synthesis.

    PubMed Central

    Mullinix, K P; Wetekam, W; Deeley, R G; Gordon, J I; Meyers, M; Kent, K A; Goldberger, R F

    1976-01-01

    We have investigated the estrogen-mediated induction of vitellogenin synthesis in rooster liver. We compared the concentrations of vitellogenin messenger RNA (mRNA) in the liver with the concentrations of vitellogenin in the sera of roosters that had recieved various treatments with estrogen. We found no vitellogenin mRNA in the livers of the unstimulated roosters. An initial injection of estrogen was attended by de novo synthesis of vitellogenin mRNA in the liver and accumulation of vitellogenin in the serum. When vitellogenin was no longer present in the serum or liver (the "post-estrogen-serum-negative" state), the liver was found to contain appreciable amounts of vitellogenin mRNA. This mRNA was of the same size as that found in the liver of the rooster actively synthesizing vitellogenin in response to estrogen. Whereas vitellogenin mRNA was in large polysomes in the livers of the roosters actively synthesizing vitellogenin, the vitellogenin mRNA in the liver of the post-estrogen-serum-negative rooster was not associated with polysomes. The possible relevance of these findings to the fact that the rooster responds differently to a primary stimulation with estrogen than to subsequent stimulations is discussed. PMID:1064017

  6. Chromophore-assisted light inactivation of pKi-67 leads to inhibition of ribosomal RNA synthesis.

    PubMed

    Rahmanzadeh, R; Hüttmann, G; Gerdes, J; Scholzen, T

    2007-06-01

    Expression of the nuclear Ki-67 protein (pKi-67) is strongly associated with cell proliferation. For this reason, antibodies against this protein are widely used as prognostic tools for the assessment of cell proliferation in biopsies from cancer patients. Despite this broad application in histopathology, functional evidence for the physiological role of pKi-67 is still missing. Recently, we proposed a function of pKi-67 in the early steps of ribosomal RNA (rRNA) synthesis. Here, we have examined the involvement of pKi-67 in this process by photochemical inhibition using chromophore-assisted light inactivation (CALI). Anti-pKi-67 antibodies were labelled with the fluorochrome fluorescein 5(6)-isothiocyanate and were irradiated after binding to their target protein. Performing CALI in vitro on cell lysates led to specific cross-linking of pKi-67. Moreover, the upstream binding factor (UBF) necessary for rRNA transcription was also partly subjected to cross-link formation, indicating a close spatial proximity of UBF and pKi-67. CALI in living cells, using micro-injected antibody, caused a striking relocalization of UBF from foci within the nucleoli to spots located at the nucleolar rim or within the nucleoplasm. pKi-67-CALI resulted in dramatic inhibition of RNA polymerase I-dependent nucleolar rRNA synthesis, whereas RNA polymerase II-dependent nucleoplasmic RNA synthesis remained almost unaltered. Our data presented here argue for a crucial role of pKi-67 in RNA polymerase I-dependent nucleolar rRNA synthesis.

  7. A mitochondrial locus is necessary for the synthesis of mitochondrial tRNA in the yeast Saccharomyces cerevisiae.

    PubMed Central

    Martin, N C; Underbrink-Lyon, K

    1981-01-01

    We have used a cloned yeast mitochondrial tRNAUCNSer gene as a probe to detect RNA species that are transcripts from this gene in wild-type Saccharomyces cerevisiae and in petite deletion mutants. In RNA from wild-type cells, the tRNA is the most prominent transcript of the gene. In RNA from deletion mutants that retain this gene but have lost other regions of mtDNA, high molecular weight transcripts containing the tRNAUCNSer sequences accumulate but tRNAUCNSer is not made. tRNAUCNSer synthesis can be restored in these mutants when they are mated to other deletion mutants that retain a different portion of the mitochondrial genome. Protein synthesis is not necessary for the restoration, and the restoration is not due to a nuclear effect or to an effect of mating alone, because strains without mtDNA are not able to restore tRNA synthesis. These results definitively demonstrate the existence of a yeast mitochondrial locus that is necessary for tRNA synthesis and, because the restoration of tRNAUCNSer synthesis appears to result from intergenic complementation, not recombination, indicate that this locus acts in trans. Images PMID:6795621

  8. A genetically encoded fluorescent tRNA is active in live-cell protein synthesis

    PubMed Central

    Masuda, Isao; Igarashi, Takao; Sakaguchi, Reiko; Nitharwal, Ram G.; Takase, Ryuichi; Han, Kyu Young; Leslie, Benjamin J.; Liu, Cuiping; Gamper, Howard; Ha, Taekjip; Sanyal, Suparna

    2017-01-01

    Abstract Transfer RNAs (tRNAs) perform essential tasks for all living cells. They are major components of the ribosomal machinery for protein synthesis and they also serve in non-ribosomal pathways for regulation and signaling metabolism. We describe the development of a genetically encoded fluorescent tRNA fusion with the potential for imaging in live Escherichia coli cells. This tRNA fusion carries a Spinach aptamer that becomes fluorescent upon binding of a cell-permeable and non-toxic fluorophore. We show that, despite having a structural framework significantly larger than any natural tRNA species, this fusion is a viable probe for monitoring tRNA stability in a cellular quality control mechanism that degrades structurally damaged tRNA. Importantly, this fusion is active in E. coli live-cell protein synthesis allowing peptidyl transfer at a rate sufficient to support cell growth, indicating that it is accommodated by translating ribosomes. Imaging analysis shows that this fusion and ribosomes are both excluded from the nucleoid, indicating that the fusion and ribosomes are in the cytosol together possibly engaged in protein synthesis. This fusion methodology has the potential for developing new tools for live-cell imaging of tRNA with the unique advantage of both stoichiometric labeling and broader application to all cells amenable to genetic engineering. PMID:27956502

  9. SARS-unique fold in the Rousettus bat coronavirus HKU9.

    PubMed

    Hammond, Robert G; Tan, Xuan; Johnson, Margaret A

    2017-09-01

    The coronavirus nonstructural protein 3 (nsp3) is a multifunctional protein that comprises multiple structural domains. This protein assists viral polyprotein cleavage, host immune interference, and may play other roles in genome replication or transcription. Here, we report the solution NMR structure of a protein from the "SARS-unique region" of the bat coronavirus HKU9. The protein contains a frataxin fold or double-wing motif, which is an α + β fold that is associated with protein/protein interactions, DNA binding, and metal ion binding. High structural similarity to the human severe acute respiratory syndrome (SARS) coronavirus nsp3 is present. A possible functional site that is conserved among some betacoronaviruses has been identified using bioinformatics and biochemical analyses. This structure provides strong experimental support for the recent proposal advanced by us and others that the "SARS-unique" region is not unique to the human SARS virus, but is conserved among several different phylogenetic groups of coronaviruses and provides essential functions. © 2017 The Protein Society.

  10. Asphalt, water, and the prebiotic synthesis of ribose, ribonucleosides, and RNA.

    PubMed

    Benner, Steven A; Kim, Hyo-Joong; Carrigan, Matthew A

    2012-12-18

    RNA has been called a "prebiotic chemist's nightmare" because of its combination of large size, carbohydrate building blocks, bonds that are thermodynamically unstable in water, and overall intrinsic instability. However, a discontinuous synthesis model is well-supported by experimental work that might produce RNA from atmospheric CO(2), H(2)O, and N(2). For example, electrical discharge in such atmospheres gives formaldehyde (HCHO) in large amounts and glycolaldehyde (HOCH(2)CHO) in small amounts. When rained into alkaline aquifers generated by serpentinizing rocks, these substances were undoubtedly converted to carbohydrates including ribose. Likewise, atmospherically generated HCN was undoubtedly converted in these aquifers to formamide and ammonium formate, precursors for RNA nucleobases. Finally, high reduction potentials maintained by mantle-derived rocks and minerals would allow phosphite to be present in equilibrium with phosphate, mobilizing otherwise insoluble phosphorus for the prebiotic synthesis of phosphite and phosphate esters after oxidation. So why does the community not view this discontinuous synthesis model as compelling evidence for the RNA-first hypothesis for the origin of life? In part, the model is deficient because no experiments have joined together those steps without human intervention. Further, many steps in the model have problems. Some are successful only if reactive compounds are presented in a specific order in large amounts. Failing controlled addition, the result produces complex mixtures that are inauspicious precursors for biology, a situation described as the "asphalt problem". Many bonds in RNA are thermodynamically unstable with respect to hydrolysis in water, creating a "water problem". Finally, some bonds in RNA appear to be "impossible" to form under any conditions considered plausible for early Earth. To get a community-acceptable "RNA first" model for the origin of life, the discontinuous synthesis model must be

  11. The Battle of RNA Synthesis: Virus versus Host.

    PubMed

    Harwig, Alex; Landick, Robert; Berkhout, Ben

    2017-10-21

    Transcription control is the foundation of gene regulation. Whereas a cell is fully equipped for this task, viruses often depend on the host to supply tools for their transcription program. Over the course of evolution and adaptation, viruses have found diverse ways to optimally exploit cellular host processes such as transcription to their own benefit. Just as cells are increasingly understood to employ nascent RNAs in transcription regulation, recent discoveries are revealing how viruses use nascent RNAs to benefit their own gene expression. In this review, we first outline the two different transcription programs used by viruses, i.e., transcription (DNA-dependent) and RNA-dependent RNA synthesis. Subsequently, we use the distinct stages (initiation, elongation, termination) to describe the latest insights into nascent RNA-mediated regulation in the context of each relevant stage.

  12. Supramolecular Architecture of the Coronavirus Particle.

    PubMed

    Neuman, B W; Buchmeier, M J

    2016-01-01

    Coronavirus particles serve three fundamentally important functions in infection. The virion provides the means to deliver the viral genome across the plasma membrane of a host cell. The virion is also a means of escape for newly synthesized genomes. Lastly, the virion is a durable vessel that protects the genome on its journey between cells. This review summarizes the available X-ray crystallography, NMR, and cryoelectron microscopy structural data for coronavirus structural proteins, and looks at the role of each of the major structural proteins in virus entry and assembly. The potential wider conservation of the nucleoprotein fold identified in the Arteriviridae and Coronaviridae families and a speculative model for the evolution of corona-like virus architecture are discussed. © 2016 Elsevier Inc. All rights reserved.

  13. Two distinct sets of NS2A molecules are responsible for dengue virus RNA synthesis and virion assembly.

    PubMed

    Xie, Xuping; Zou, Jing; Puttikhunt, Chunya; Yuan, Zhiming; Shi, Pei-Yong

    2015-01-15

    Flavivirus nonstructural protein 2A (NS2A) plays important roles in both viral RNA synthesis and virion assembly. The molecular details of how the NS2A protein modulates the two distinct events have not been defined. To address this question, we have performed a systematic mutagenesis of NS2A using dengue virus (DENV) serotype 2 (DENV-2) as a model. We identified two sets of NS2A mutations with distinct defects during a viral infection cycle. One set of NS2A mutations (D125A and G200A) selectively abolished viral RNA synthesis. Mechanistically, the D125A mutation abolished viral RNA synthesis through blocking the N-terminal cleavage of the NS2A protein, leading to an unprocessed NS1-NS2A protein; this result suggests that amino acid D125 (far downstream of the N terminus of NS2A) may contribute to the recognition of host protease at the NS1-NS2A junction. The other set of NS2A mutations (G11A, E20A, E100A, Q187A, and K188A) specifically impaired virion assembly without significantly affecting viral RNA synthesis. Remarkably, mutants defective in virion assembly could be rescued by supplying in trans wild-type NS2A molecules expressed from a replicative replicon, by wild-type NS2A protein expressed alone, by a mutant NS2A (G200A) that is lethal for viral RNA synthesis, or by a different mutant NS2A that is defective in virion assembly. In contrast, none of the mutants defective in viral RNA synthesis could be rescued by trans-complementation. Collectively, the results indicate that two distinct sets of NS2A molecules are responsible for DENV RNA synthesis and virion assembly. Dengue virus (DENV) represents the most prevalent mosquito-borne human pathogen. Understanding the replication of DENV is essential for development of vaccines and therapeutics. Here we characterized the function of DENV-2 NS2A using a systematic mutagenesis approach. The mutagenesis results revealed two distinct sets of NS2A mutations: one set of mutations that result in defects in viral RNA

  14. Poliovirus RNA synthesis in vitro: structural elements and antibody inhibition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Semler, B.L.; Hanecak, R.; Dorner, L.F.

    1983-01-01

    The poliovirus RNA polymerase complex has been analyzed by immunoautoradiography using antibody probes derived from purified replicase (P3) region viral polypeptides. Antibody preparations made against the polio RNA polymerase, P3-4b, detected a previously unreported cellular protein that copurifies with the RNA polymerase. An IgG fraction purified from rabbit antiserum to polypeptide P3-2, a precursor fo the RNA polymerase, specifically inhibits poliovirus RNA synthesis in vitro. The authors have also immunoprecipitated a 60,000-dalton protein (P3-4a) with antiserum to protein P3-4b and have determined the precise genomic map position of this protein by automated Edman degradation. Protein P3-4a originates by cleavage ofmore » the RNA polymerase precursor at a glutamine-glucine amino acid pair not previously reported to be a viral cleavage site.« less

  15. DECOUPLING OF PROTEIN AND RNA SYNTHESIS DURING DEUTERIUM PARTHENOGENESIS IN SEA URCHIN EGGS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gross, P.R.; Spindel, W.; Cousineau, G.H.

    1963-10-29

    The parthenogenetic activation of cell division and suppression of nucleic acid synthesis by deuterium in eggs of sea urchins was investigated. D/ sub 2/O treatment was found to evoke a high rate of protein synthesis in the eggs that was maintained for several hours. However, eggs whose protein synthesis was activated and that were making labeled cytasters showed no increment in RNA synthesis over controls. (P.C.H.)

  16. Excretion and detection of SARS coronavirus and its nucleic acid from digestive system

    PubMed Central

    Wang, Xin-Wei; Li, Jin-Song; Guo, Ting-Kai; Zhen, Bei; Kong, Qing-Xin; Yi, Bin; Li, Zhong; Song, Nong; Jin, Min; Wu, Xiao-Ming; Xiao, Wen-Jun; Zhu, Xiu-Mei; Gu, Chang-Qing; Yin, Jing; Wei, Wei; Yao, Wei; Liu, Chao; Li, Jian-Feng; Ou, Guo-Rong; Wang, Min-Nian; Fang, Tong-Yu; Wang, Gui-Jie; Qiu, Yao-Hui; Wu, Huai-Huan; Chao, Fu-Huan; Li, Jun-Wen

    2005-01-01

    AIM: To study whether severe acute respiratory syndrome coronavirus (SARS-CoV) could be excreted from digestive system. METHODS: Cell culture and semi-nested RT-PCR were used to detect SARS-CoV and its RNA from 21 stool and urine samples, and a kind of electropositive filter media particles was used to concentrate the virus in 10 sewage samples from two hospitals receiving SARS patients in Beijing in China. RESULTS: It was demonstrated that there was no live SARS-CoV in all samples collected, but the RNA of SARS-CoV could be detected in seven stool samples from SARS patients with any one of the symptoms of fever, malaise, cough, or dyspnea, in 10 sewage samples before disinfection and 3 samples after disinfection from the two hospitals. The RNA could not be detected in urine and stool samples from patients recovered from SARS. CONCLUSION: Nucleic acid of SARS-CoV can be excreted through the stool of patients into sewage system, and the possibility of SARS-CoV transmitting through digestive system cannot be excluded. PMID:16038039

  17. MERS, SARS and other coronaviruses as causes of pneumonia.

    PubMed

    Yin, Yudong; Wunderink, Richard G

    2018-02-01

    Human coronaviruses (HCoVs) have been considered to be relatively harmless respiratory pathogens in the past. However, after the outbreak of the severe acute respiratory syndrome (SARS) and emergence of the Middle East respiratory syndrome (MERS), HCoVs have received worldwide attention as important pathogens in respiratory tract infection. This review focuses on the epidemiology, pathogenesis and clinical characteristics among SARS-coronaviruses (CoV), MERS-CoV and other HCoV infections. © 2017 Asian Pacific Society of Respirology.

  18. Receptor recognition and cross-species infections of SARS coronavirus

    PubMed Central

    Li, Fang

    2013-01-01

    Receptor recognition is a major determinant of the host range, cross-species infections, and pathogenesis of the severe acute respiratory syndrome coronavirus (SARS-CoV). A defined receptor-binding domain (RBD) in the SARS-CoV spike protein specifically recognizes its host receptor, angiotensin-converting enzyme 2 (ACE2). This article reviews the latest knowledge about how RBDs from different SARS-CoV strains interact with ACE2 from several animal species. Detailed research on these RBD/ACE2 interactions has established important principles on host receptor adaptations, cross-species infections, and future evolution of SARS-CoV. These principles may apply to other emerging animal viruses, including the recently emerged Middle East respiratory syndrome coronavirus (MERS-CoV). This paper forms part of a series of invited articles in Antiviral Research on “From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses.” PMID:23994189

  19. In Vitro Synthesis of Minus-Strand RNA by an Isolated Cereal Yellow Dwarf Virus RNA-Dependent RNA Polymerase Requires VPg and a Stem-Loop Structure at the 3′ End of the Virus RNA▿

    PubMed Central

    Osman, Toba A. M.; Coutts, Robert H. A.; Buck, Kenneth W.

    2006-01-01

    Cereal yellow dwarf virus (CYDV) RNA has a 5′-terminal genome-linked protein (VPg). We have expressed the VPg region of the CYDV genome in bacteria and used the purified protein (bVPg) to raise an antiserum which was able to detect free VPg in extracts of CYDV-infected oat plants. A template-dependent RNA-dependent RNA polymerase (RdRp) has been produced from a CYDV membrane-bound RNA polymerase by treatment with BAL 31 nuclease. The RdRp was template specific, being able to utilize templates from CYDV plus- and minus-strand RNAs but not those of three unrelated viruses, Red clover necrotic mosaic virus, Cucumber mosaic virus, and Tobacco mosaic virus. RNA synthesis catalyzed by the RdRp required a 3′-terminal GU sequence and the presence of bVPg. Additionally, synthesis of minus-strand RNA on a plus-strand RNA template required the presence of a putative stem-loop structure near the 3′ terminus of CYDV RNA. The base-paired stem, a single-nucleotide (A) bulge in the stem, and the sequence of a tetraloop were all required for the template activity. Evidence was produced showing that minus-strand synthesis in vitro was initiated by priming by bVPg at the 3′ end of the template. The data are consistent with a model in which the RdRp binds to the stem-loop structure which positions the active site to recognize the 3′-terminal GU sequence for initiation of RNA synthesis by the addition of an A residue to VPg. PMID:16928757

  20. Synthesis of capped RNA using a DMT group as a purification handle.

    PubMed

    Veliath, Elizabeth; Gaffney, Barbara L; Jones, Roger A

    2014-01-01

    We report a new method for synthesis of capped RNA or 2'-OMe RNA that uses a N(2-)4,4'-dimethoxytrityl (DMT) group as a lipophilic purification handle to allow convenient isolation and purification of the capped RNA. The DMT group is easily removed under mild conditions without degradation of the cap. We have used this approach to prepare capped 10- and 20-mers. This method is compatible with the many condensation reactions that have been reported for preparation of capped RNA or cap analogues.

  1. TIF-IA and Ebp1 regulate RNA synthesis in T cells.

    PubMed

    Saudemont, Aurore

    2015-04-16

    In this issue of Blood, Nguyen et al show that mycophenolic acid (MPA) induces GTP depletion, which inhibits the function of transcription initiation factor I (TIF-IA) and impacts the interaction of TIF-IA with ErbB3-binding protein 1 (Ebp1), a key in regulating proliferating cell nuclear antigen (PCNA) expression and ribosomal RNA (rRNA) synthesis in T cells during activation.

  2. Receptor recognition and cross-species infections of SARS coronavirus.

    PubMed

    Li, Fang

    2013-10-01

    Receptor recognition is a major determinant of the host range, cross-species infections, and pathogenesis of the severe acute respiratory syndrome coronavirus (SARS-CoV). A defined receptor-binding domain (RBD) in the SARS-CoV spike protein specifically recognizes its host receptor, angiotensin-converting enzyme 2 (ACE2). This article reviews the latest knowledge about how RBDs from different SARS-CoV strains interact with ACE2 from several animal species. Detailed research on these RBD/ACE2 interactions has established important principles on host receptor adaptations, cross-species infections, and future evolution of SARS-CoV. These principles may apply to other emerging animal viruses, including the recently emerged Middle East respiratory syndrome coronavirus (MERS-CoV). This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10years of research on highly pathogenic human coronaviruses". Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Solid-Phase Synthesis of RNA Analogs Containing Phosphorodithioate Linkages.

    PubMed

    Yang, Xianbin

    2017-09-18

    The oligoribonucleotide phosphorodithioate (PS2-RNA) modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphorodiester backbone linkage. Like a natural phosphodiester RNA backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-RNAs are highly stable to nucleases and several in vitro assays have demonstrated their biological activity. For example, PS2-RNAs silenced mRNA in vitro and bound to protein targets in the form of PS2-aptamers (thioaptamers). Thus, the interest in and promise of PS2-RNAs has drawn attention to synthesizing, isolating, and characterizing these compounds. RNA-thiophosphoramidite monomers are commercially available from AM Biotechnologies and this unit describes an effective methodology for solid-phase synthesis, deprotection, and purification of RNAs having PS2 internucleotide linkages. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  4. Discovery of Novel Bat Coronaviruses in South China That Use the Same Receptor as Middle East Respiratory Syndrome Coronavirus.

    PubMed

    Luo, Chu-Ming; Wang, Ning; Yang, Xing-Lou; Liu, Hai-Zhou; Zhang, Wei; Li, Bei; Hu, Ben; Peng, Cheng; Geng, Qi-Bin; Zhu, Guang-Jian; Li, Fang; Shi, Zheng-Li

    2018-07-01

    Middle East respiratory syndrome coronavirus (MERS-CoV) has represented a human health threat since 2012. Although several MERS-related CoVs that belong to the same species as MERS-CoV have been identified from bats, they do not use the MERS-CoV receptor, dipeptidyl peptidase 4 (DPP4). Here, we screened 1,059 bat samples from at least 30 bat species collected in different regions in south China and identified 89 strains of lineage C betacoronaviruses, including Tylonycteris pachypus coronavirus HKU4 , Pipistrellus pipistrellus coronavirus HKU5 , and MERS-related CoVs. We sequenced the full-length genomes of two positive samples collected from the great evening bat, Ia io , from Guangdong Province. The two genomes were highly similar and exhibited genomic structures identical to those of other lineage C betacoronaviruses. While they exhibited genome-wide nucleotide identities of only 75.3 to 81.2% with other MERS-related CoVs, their gene-coding regions were highly similar to their counterparts, except in the case of the spike proteins. Further protein-protein interaction assays demonstrated that the spike proteins of these MERS-related CoVs bind to the receptor DPP4. Recombination analysis suggested that the newly discovered MERS-related CoVs have acquired their spike genes from a DPP4-recognizing bat coronavirus HKU4. Our study provides further evidence that bats represent the evolutionary origins of MERS-CoV. IMPORTANCE Previous studies suggested that MERS-CoV originated in bats. However, its evolutionary path from bats to humans remains unclear. In this study, we discovered 89 novel lineage C betacoronaviruses in eight bat species. We provide evidence of a MERS-related CoV derived from the great evening bat that uses the same host receptor as human MERS-CoV. This virus also provides evidence for a natural recombination event between the bat MERS-related CoV and another bat coronavirus, HKU4. Our study expands the host ranges of MERS-related CoV and represents an

  5. MXD1 localizes in the nucleolus, binds UBF and impairs rRNA synthesis.

    PubMed

    Lafita-Navarro, Maria Del Carmen; Blanco, Rosa; Mata-Garrido, Jorge; Liaño-Pons, Judit; Tapia, Olga; García-Gutiérrez, Lucía; García-Alegría, Eva; Berciano, María T; Lafarga, Miguel; León, Javier

    2016-10-25

    MXD1 is a protein that interacts with MAX, to form a repressive transcription factor. MXD1-MAX binds E-boxes. MXD1-MAX antagonizes the transcriptional activity of the MYC oncoprotein in most models. It has been reported that MYC overexpression leads to augmented RNA synthesis and ribosome biogenesis, which is a relevant activity in MYC-mediated tumorigenesis. Here we describe that MXD1, but not MYC or MNT, localizes to the nucleolus in a wide array of cell lines derived from different tissues (carcinoma, leukemia) as well as in embryonic stem cells. MXD1 also localizes in the nucleolus of primary tissue cells as neurons and Sertoli cells. The nucleolar localization of MXD1 was confirmed by co-localization with UBF. Co-immunoprecipitation experiments showed that MXD1 interacted with UBF and proximity ligase assays revealed that this interaction takes place in the nucleolus. Furthermore, chromatin immunoprecipitation assays showed that MXD1 was bound in the transcribed rDNA chromatin, where it co-localizes with UBF, but also in the ribosomal intergenic regions. The MXD1 involvement in rRNA synthesis was also suggested by the nucleolar segregation upon rRNA synthesis inhibition by actinomycin D. Silencing of MXD1 with siRNAs resulted in increased synthesis of pre-rRNA while enforced MXD1 expression reduces it. The results suggest a new role for MXD1, which is the control of ribosome biogenesis. This new MXD1 function would be important to curb MYC activity in tumor cells.

  6. MXD1 localizes in the nucleolus, binds UBF and impairs rRNA synthesis

    PubMed Central

    Lafita-Navarro, Maria del Carmen; Blanco, Rosa; Mata-Garrido, Jorge; Liaño-Pons, Judit; Tapia, Olga; García-Gutiérrez, Lucía; García-Alegría, Eva; Berciano, María T.; Lafarga, Miguel; León, Javier

    2016-01-01

    MXD1 is a protein that interacts with MAX, to form a repressive transcription factor. MXD1-MAX binds E-boxes. MXD1-MAX antagonizes the transcriptional activity of the MYC oncoprotein in most models. It has been reported that MYC overexpression leads to augmented RNA synthesis and ribosome biogenesis, which is a relevant activity in MYC-mediated tumorigenesis. Here we describe that MXD1, but not MYC or MNT, localizes to the nucleolus in a wide array of cell lines derived from different tissues (carcinoma, leukemia) as well as in embryonic stem cells. MXD1 also localizes in the nucleolus of primary tissue cells as neurons and Sertoli cells. The nucleolar localization of MXD1 was confirmed by co-localization with UBF. Co-immunoprecipitation experiments showed that MXD1 interacted with UBF and proximity ligase assays revealed that this interaction takes place in the nucleolus. Furthermore, chromatin immunoprecipitation assays showed that MXD1 was bound in the transcribed rDNA chromatin, where it co-localizes with UBF, but also in the ribosomal intergenic regions. The MXD1 involvement in rRNA synthesis was also suggested by the nucleolar segregation upon rRNA synthesis inhibition by actinomycin D. Silencing of MXD1 with siRNAs resulted in increased synthesis of pre-rRNA while enforced MXD1 expression reduces it. The results suggest a new role for MXD1, which is the control of ribosome biogenesis. This new MXD1 function would be important to curb MYC activity in tumor cells. PMID:27588501

  7. RNA synthesis is modulated by G-quadruplex formation in Hepatitis C virus negative RNA strand.

    PubMed

    Chloé, Jaubert; Amina, Bedrat; Laura, Bartolucci; Carmelo, Di Primo; Michel, Ventura; Jean-Louis, Mergny; Samir, Amrane; Marie-Line, Andreola

    2018-05-25

    DNA and RNA guanine-rich oligonucleotides can form non-canonical structures called G-quadruplexes or "G4" that are based on the stacking of G-quartets. The role of DNA and RNA G4 is documented in eukaryotic cells and in pathogens such as viruses. Yet, G4 have been identified only in a few RNA viruses, including the Flaviviridae family. In this study, we analysed the last 157 nucleotides at the 3'end of the HCV (-) strand. This sequence is known to be the minimal sequence required for an efficient RNA replication. Using bioinformatics and biophysics, we identified a highly conserved G4-prone sequence located in the stem-loop IIy' of the negative strand. We also showed that the formation of this G-quadruplex inhibits the in vitro RNA synthesis by the RdRp. Furthermore, Phen-DC3, a specific G-quadruplex binder, is able to inhibit HCV viral replication in cells in conditions where no cytotoxicity was measured. Considering that this domain of the negative RNA strand is well conserved among HCV genotypes, G4 ligands could be of interest for new antiviral therapies.

  8. VHL negatively regulates SARS coronavirus replication by modulating nsp16 ubiquitination and stability.

    PubMed

    Yu, Xiao; Chen, Shuliang; Hou, Panpan; Wang, Min; Chen, Yu; Guo, Deyin

    2015-04-03

    Eukaryotic cellular and most viral RNAs carry a 5'-terminal cap structure, a 5'-5' triphosphate linkage between the 5' end of the RNA and a guanosine nucleotide (cap-0). SARS coronavirus (SARS-CoV) nonstructural protein nsp16 functions as a methyltransferase, to methylate mRNA cap-0 structure at the ribose 2'-O position of the first nucleotide to form cap-1 structures. However, whether there is interplay between nsp16 and host proteins was not yet clear. In this report, we identified several potential cellular nsp16-interacting proteins from a human thymus cDNA library by yeast two-hybrid screening. VHL, one of these proteins, was proven to interact with nsp16 both in vitro and in vivo. Further studies showed that VHL can inhibit SARS-CoV replication by regulating nsp16 ubiquitination and promoting its degradation. Our results have revealed the role of cellular VHL in the regulation of SARS-CoV replication. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Interaction of SARS and MERS Coronaviruses with the Antiviral Interferon Response.

    PubMed

    Kindler, E; Thiel, V; Weber, F

    2016-01-01

    Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) are the most severe coronavirus (CoV)-associated diseases in humans. The causative agents, SARS-CoV and MERS-CoV, are of zoonotic origin but may be transmitted to humans, causing severe and often fatal respiratory disease in their new host. The two coronaviruses are thought to encode an unusually large number of factors that allow them to thrive and replicate in the presence of efficient host defense mechanisms, especially the antiviral interferon system. Here, we review the recent progress in our understanding of the strategies that highly pathogenic coronaviruses employ to escape, dampen, or block the antiviral interferon response in human cells. © 2016 Elsevier Inc. All rights reserved.

  10. The roles of transportation and transportation hubs in the propagation of influenza and coronaviruses: a systematic review.

    PubMed

    Browne, Annie; Ahmad, Sacha St-Onge; Beck, Charles R; Nguyen-Van-Tam, Jonathan S

    2016-01-01

    Respiratory viruses spread in humans across wide geographical areas in short periods of time, resulting in high levels of morbidity and mortality. We undertook a systematic review to assess the evidence that air, ground and sea mass transportation systems or hubs are associated with propagating influenza and coronaviruses. Healthcare databases and sources of grey literature were searched using pre-defined criteria between April and June 2014. Two reviewers screened all identified records against the protocol, undertook risk of bias assessments and extracted data using a piloted form. Results were analysed using a narrative synthesis. Forty-one studies met the eligibility criteria. Risk of bias was high in the observational studies, moderate to high in the reviews and moderate to low in the modelling studies. In-flight influenza transmission was identified substantively on five flights with up to four confirmed and six suspected secondary cases per affected flight. Five studies highlighted the role of air travel in accelerating influenza spread to new areas. Influenza outbreaks aboard cruise ships affect 2-7% of passengers. Influenza transmission events have been observed aboard ground transport vehicles. High heterogeneity between studies and the inability to exclude other sources of infection means that the risk of influenza transmission from an index case to other passengers cannot be accurately quantified. A paucity of evidence was identified describing severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus transmission events associated with transportation systems or hubs. Air transportation appears important in accelerating and amplifying influenza propagation. Transmission occurs aboard aeroplanes, at the destination and possibly at airports. Control measures to prevent influenza transmission on cruise ships are needed to reduce morbidity and mortality. There is no recent evidence of sea transport accelerating influenza

  11. Guanosine 3'-diphosphate 5'-diphosphate is not required for growth rate-dependent control of rRNA synthesis in Escherichia coli.

    PubMed Central

    Gaal, T; Gourse, R L

    1990-01-01

    rRNA synthesis in Escherichia coli is subject to at least two regulation systems, growth rate-dependent control and stringent control. The inverse correlation between rRNA synthesis rates and guanosine 3'-diphosphate 5'-diphosphate (ppGpp) levels under various physiological conditions has led to the supposition that ppGpp is the mediator of both control mechanisms by inhibiting transcription from rrn P1 promoters. Recently, relA- spoT- strains have been constructed in which both ppGpp synthesis pathways most likely have been removed (M. Cashel, personal communication). We have confirmed that such strains produce no detectable ppGpp and therefore offer a direct means for testing the involvement of ppGpp in the regulation of rRNA synthesis in vivo. Stringent control was determined by measurement of rRNA synthesis after amino acid starvation, while growth rate control was determined by measurement of rRNA synthesis under different nutritional conditions. As expected, the relA- spoT- strain is relaxed for stringent control. However, growth rate-dependent regulation is unimpaired. These results indicate that growth rate regulation can occur in the absence of ppGpp and imply that ppGpp is not the mediator, or at least is not the sole mediator, of growth rate-dependent control. Therefore, growth rate-dependent control and stringent control may utilize different mechanisms for regulating stable RNA synthesis. PMID:2196571

  12. Coronaviruses and arteriviruses display striking differences in their cyclophilin A-dependence during replication in cell culture.

    PubMed

    de Wilde, Adriaan H; Zevenhoven-Dobbe, Jessika C; Beugeling, Corrine; Chatterji, Udayan; de Jong, Danielle; Gallay, Philippe; Szuhai, Karoly; Posthuma, Clara C; Snijder, Eric J

    2018-04-01

    Cyclophilin A (CypA) is an important host factor in the replication of a variety of RNA viruses. Also the replication of several nidoviruses was reported to depend on CypA, although possibly not to the same extent. These prior studies are difficult to compare, since different nidoviruses, cell lines and experimental set-ups were used. Here, we investigated the CypA dependence of three distantly related nidoviruses that can all replicate in Huh7 cells: the arterivirus equine arteritis virus (EAV), the alphacoronavirus human coronavirus 229E (HCoV-229E), and the betacoronavirus Middle East respiratory syndrome coronavirus (MERS-CoV). The replication of these viruses was compared in the same parental Huh7 cells and in CypA-knockout Huh7 cells generated using CRISPR/Cas9-technology. CypA depletion reduced EAV yields by ~ 3-log, whereas MERS-CoV progeny titers were modestly reduced (3-fold) and HCoV-229E replication was unchanged. This study reveals that the replication of nidoviruses can differ strikingly in its dependence on cellular CypA. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  13. The "Speedy" Synthesis of Atom-Specific (15)N Imino/Amido-Labeled RNA.

    PubMed

    Neuner, Sandro; Santner, Tobias; Kreutz, Christoph; Micura, Ronald

    2015-08-10

    Although numerous reports on the synthesis of atom-specific (15)N-labeled nucleosides exist, fast and facile access to the corresponding phosphoramidites for RNA solid-phase synthesis is still lacking. This situation represents a severe bottleneck for NMR spectroscopic investigations on functional RNAs. Here, we present optimized procedures to speed up the synthesis of (15)N(1) adenosine and (15)N(1) guanosine amidites, which are the much needed counterparts of the more straightforward-to-achieve (15)N(3) uridine and (15)N(3) cytidine amidites in order to tap full potential of (1)H/(15)N/(15)N-COSY experiments for directly monitoring individual Watson-Crick base pairs in RNA. Demonstrated for two preQ1 riboswitch systems, we exemplify a versatile concept for individual base-pair labeling in the analysis of conformationally flexible RNAs when competing structures and conformational dynamics are encountered. © 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. RNA synthesis in the pancreatic acinar cells of aging mice as revealed by electron microscopic radioautography.

    PubMed

    Nagata, Tetsuji

    2012-01-01

    For the purpose of studying the aging changes of macromolecular synthesis in the pancreatic acinar cells of experimental animals, we studied 10 groups of aging mice during development and aging from fetal day 19 to postnatal month 24. They were injected with 3H-uridine, a precursor for RNA synthesis, sacrificed and the pancreatic tissues were taken out, fixed and processed for light and electron microscopic radioautography. On many radioautograms the localization of silver grains demonstrating RNA synthesis in pancreatic acinar cells in respective aging groups were analyzed qualitatively. The number of mitochondria per cell, the number of labeled mitochondria with silver grains and the number of silver grains in each cell in respective aging groups were analyzed quantitatively in relation to the aging of animals. The results revealed that the RNA synthetic activity as expressed by the incorporations of RNA precursor, i.e., the number of silver grains in cell nuclei, cell organelles, changed due to the aging of animals. The number of mitochondria, the number of labeled mitochondria and the mitochondrial labeling index labeled with silver grains were counted in each pancreatic acinar cell. It was demonstrated that the number of mitochondria, the number of labeled mitochondria and the labeling indices showing RNA synthesis at various ages increased from embryonic day 19 to postnatal newborn day 1, 3, 9, 14, adult month 1, 2 and 6, reaching the maxima, then decreased to senile stage at postnatal year 1 to 2, indicating the aging changes. Based upon our findings, available literature on macromolecular synthesis in mitochondria of various cells are reviewed.

  15. Detection and characterisation of coronaviruses in migratory and non-migratory Australian wild birds.

    PubMed

    Chamings, Anthony; Nelson, Tiffanie M; Vibin, Jessy; Wille, Michelle; Klaassen, Marcel; Alexandersen, Soren

    2018-04-13

    We evaluated the presence of coronaviruses by PCR in 918 Australian wild bird samples collected during 2016-17. Coronaviruses were detected in 141 samples (15.3%) from species of ducks, shorebirds and herons and from multiple sampling locations. Sequencing of selected positive samples found mainly gammacoronaviruses, but also some deltacoronaviruses. The detection rate of coronaviruses was improved by using multiple PCR assays, as no single assay could detect all coronavirus positive samples. Sequencing of the relatively conserved Orf1 PCR amplicons found that Australian duck gammacoronaviruses were similar to duck gammacoronaviruses around the world. Some sequenced shorebird gammacoronaviruses belonged to Charadriiformes lineages, but others were more closely related to duck gammacoronaviruses. Australian duck and heron deltacoronaviruses belonged to lineages with other duck and heron deltacoronaviruses, but were almost 20% different in nucleotide sequence to other deltacoronavirus sequences available. Deltacoronavirus sequences from shorebirds formed a lineage with a deltacoronavirus from a ruddy turnstone detected in the United States. Given that Australian duck gammacoronaviruses are highly similar to those found in other regions, and Australian ducks rarely come into contact with migratory Palearctic duck species, we hypothesise that migratory shorebirds are the important vector for moving wild bird coronaviruses into and out of Australia.

  16. Detection of the Severe Acute Respiratory Syndrome-Related Coronavirus and Alphacoronavirus in the Bat Population of Taiwan.

    PubMed

    Chen, Y-N; Phuong, V N; Chen, H C; Chou, C-H; Cheng, H-C; Wu, C-H

    2016-12-01

    Bats have been demonstrated to be natural reservoirs of severe acute respiratory syndrome coronavirus (SARS CoV) and Middle East respiratory syndrome (MERS) CoV. Faecal samples from 248 individuals of 20 bat species were tested for partial RNA-dependent RNA polymerase gene of CoV and 57 faecal samples from eight bat species were tested positive. The highest detection rate of 44% for Scotophilus kuhlii, followed by 30% for Rhinolophus monoceros. Significantly higher detection rates of coronaviral RNA were found in female bats and Scotophilus kuhlii roosting in palm trees. Phylogenetic analysis classified the positive samples into SARS-related (SARSr) CoV, Scotophilus bat CoV 512 close to those from China and Philippines, and Miniopterus bat CoV 1A-related lineages. Coronaviral RNA was also detected in bat guano from Scotophilus kuhlii and Myotis formosus flavus on the ground and had potential risk for human exposure. Diverse bat CoV with zoonotic potential could be introduced by migratory bats and maintained in the endemic bat population in Taiwan. © 2016 Blackwell Verlag GmbH.

  17. Rapid detection of MERS coronavirus-like viruses in bats: pote1ntial for tracking MERS coronavirus transmission and animal origin.

    PubMed

    Woo, Patrick C Y; Lau, Susanna K P; Chen, Yixin; Wong, Emily Y M; Chan, Kwok-Hung; Chen, Honglin; Zhang, Libiao; Xia, Ningshao; Yuen, Kwok-Yung

    2018-03-07

    Recently, we developed a monoclonal antibody-based rapid nucleocapsid protein detection assay for diagnosis of MERS coronavirus (MERS-CoV) in humans and dromedary camels. In this study, we examined the usefulness of this assay to detect other lineage C betacoronaviruses closely related to MERS-CoV in bats. The rapid MERS-CoV nucleocapsid protein detection assay was tested positive in 24 (88.9%) of 27 Tylonycteris bat CoV HKU4 (Ty-BatCoV-HKU4) RNA-positive alimentary samples of Tylonycteris pachypus and 4 (19.0%) of 21 Pipistrellus bat CoV HKU5 (Pi-BatCoV-HKU5) RNA-positive alimentary samples of Pipistrellus abramus. There was significantly more Ty-BatCoV-HKU4 RNA-positive alimentary samples than Pi-BatCoV-HKU5 RNA-positive alimentary samples that were tested positive by the rapid MERS-CoV nucleocapsid protein detection assay (P < 0.001 by Chi-square test). The rapid assay was tested negative in all 51 alimentary samples RNA-positive for alphacoronaviruses (Rhinolophus bat CoV HKU2, Myotis bat CoV HKU6, Miniopterus bat CoV HKU8 and Hipposideros batCoV HKU10) and 32 alimentary samples positive for lineage B (SARS-related Rhinolophus bat CoV HKU3) and lineage D (Rousettus bat CoV HKU9) betacoronaviruses. No significant difference was observed between the viral loads of Ty-BatCoV-HKU4/Pi-BatCoV-HKU5 RNA-positive alimentary samples that were tested positive and negative by the rapid test (Mann-Witney U test). The rapid MERS-CoV nucleocapsid protein detection assay is able to rapidly detect lineage C betacoronaviruses in bats. It detected significantly more Ty-BatCoV-HKU4 than Pi-BatCoV-HKU5 because MERS-CoV is more closely related to Ty-BatCoV-HKU4 than Pi-BatCoV-HKU5. This assay will facilitate rapid on-site mass screening of animal samples for ancestors of MERS-CoV and tracking transmission in the related bat species.

  18. Envelope Protein Palmitoylations Are Crucial for Murine Coronavirus Assembly▿

    PubMed Central

    Boscarino, Joseph A.; Logan, Hillary L.; Lacny, Jason J.; Gallagher, Thomas M.

    2008-01-01

    The coronavirus assembly process encloses a ribonucleoprotein genome into vesicles containing the lipid-embedded proteins S (spike), E (envelope), and M (membrane). This process depends on interactions with membranes that may involve palmitoylation, a common posttranslational lipidation of cysteine residues. To determine whether specific palmitoylations influence coronavirus assembly, we introduced plasmid DNAs encoding mouse hepatitis coronavirus (MHV) S, E, M, and N (nucleocapsid) into 293T cells and found that virus-like particles (VLPs) were robustly assembled and secreted into culture medium. Palmitate adducts predicted on cysteines 40, 44, and 47 of the 83-residue E protein were then evaluated by constructing mutant cDNAs with alanine or glycine codon substitutions at one or more of these positions. Triple-substituted proteins (E.Ts) lacked palmitate adducts. Both native E and E.T proteins localized at identical perinuclear locations, and both copurified with M proteins, but E.T was entirely incompetent for VLP production. In the presence of the E.T proteins, the M protein subunits accumulated into detergent-insoluble complexes that failed to secrete from cells, while native E proteins mobilized M into detergent-soluble secreted forms. Many of these observations were corroborated in the context of natural MHV infections, with native E, but not E.T, complementing debilitated recombinant MHVs lacking E. Our findings suggest that palmitoylations are essential for E to act as a vesicle morphogenetic protein and further argue that palmitoylated E proteins operate by allowing the primary coronavirus assembly subunits to assume configurations that can mobilize into secreted lipid vesicles and virions. PMID:18184706

  19. Comparative Studies of Effect of Auxin and Ethylene on Permeability and Synthesis of RNA and Protein 1

    PubMed Central

    Sacher, Joseph A.; Salminen, Seppo O.

    1969-01-01

    The effects of ethylene on permeability and RNA and protein synthesis were assayed over a 6 to 26 hr period in tissue sections from avocado (Persea gratissima Gaertn. F., var. Fuerte), both pulp and peel of banana (Musa sapientum L., var. Gros Michel), bean endocarp (Phaseolus vulgaris L., var. Kentucky Wonder Pole beans) and leaves of Rhoeo discolor. Ethylene had no effect on permeability in 4 of the 5 tissues, but sometimes enhanced solute uptake in banana peel; it had either no effect or an inhibitory effect on synthesis of RNA and protein in sections from fruits of avocado and banana. Auxin (α-naphthalene acetic acid) stimulated synthesis of RNA and protein in bean endocarp and Rhoeo leaf sections, whereas ethylene inhibited both basal and auxin-induced synthesis. It is concluded that in these tissues the auxin effect is not an ethylene effect. PMID:16657212

  20. Crucial steps in the structure determination of a coronavirus spike glycoprotein using cryo‐electron microscopy

    PubMed Central

    Walls, Alexandra; Tortorici, M. Alejandra; Bosch, Berend‐Jan; Frenz, Brandon; Rottier, Peter J. M.; DiMaio, Frank; Rey, Felix A.

    2016-01-01

    Abstract The tremendous pandemic potential of coronaviruses was demonstrated twice in the last 15 years by two global outbreaks of deadly pneumonia. Entry of coronaviruses into cells is mediated by the transmembrane spike glycoprotein S, which forms a trimer carrying receptor‐binding and membrane fusion functions. Despite their biomedical importance, coronavirus S glycoproteins have proven difficult targets for structural characterization, precluding high‐resolution studies of the biologically relevant trimer. Recent technological developments in single particle cryo‐electron microscopy allowed us to determine the first structure of a coronavirus S glycoprotein trimer which provided a framework to understand the mechanisms of viral entry and suggested potential inhibition strategies for this family of viruses. Here, we describe the key factors that enabled this breakthrough. PMID:27667334

  1. The “Speedy” Synthesis of Atom-Specific 15N Imino/Amido-Labeled RNA

    PubMed Central

    Kreutz, Christoph; Micura, Ronald

    2016-01-01

    Although numerous reports on the synthesis of atom-specific 15N-labeled nucleosides exist, fast and facile access to the corresponding phosphoramidites for RNA solid-phase synthesis is still lacking. This situation represents a severe bottleneck for NMR spectroscopic investigations on functional RNAs. Here, we present optimized procedures to speed up the synthesis of 15N(1) adenosine and 15N(1) guanosine amidites, which are the much needed counterparts of the more straightforward-to-achieve 15N(3) uridine and 15N(3) cytidine amidites in order to tap full potential of 1H/15N/15N-COSY experiments for directly monitoring individual Watson–Crick base pairs in RNA. Demonstrated for two preQ1 riboswitch systems, we exemplify a versatile concept for individual base-pair labeling in the analysis of conformationally flexible RNAs when competing structures and conformational dynamics are encountered. PMID:26237536

  2. Effects of guanosine tetraphosphate on cell-free synthesis of Escherichia coli ribosomal RNA and other gene products.

    PubMed Central

    Reiness, G; Yang, H L; Zubay, G; Cashel, M

    1975-01-01

    A cell-free system derived from E. coli is described in which mature-sized 16S and 23S ribosomal RNAs (rRNA) are synthesized at a high relative rate, comprising 17-25% of the total transcription. The addition of guanosine tetraphosphate (ppGpp) to this system results in up to a 5-fold selective inhibition of rRNA accumulation. This effect is exerted at the level of synthesis rather than degradation. It is concluded that ppGpp, which is produced in large amounts by E. coli during amino-acid deprivation, could mediate the decrease in rRNA synthesis that accompanies such deprivation. The expression of other genes has also been investigated. No selective reduction of transfer RNA synthesis by ppGpp is observed. The trp and lac operons are found to be stimulated at the transcriptional level by the presence of this nucleotide. It is hypothesized that ppGpp interacts with the RNA polymerase in such a manner as to alter the affinity of the enzyme for promoters in an operon-specific fashion. PMID:1103124

  3. A New Bat-HKU2–like Coronavirus in Swine, China, 2017

    PubMed Central

    Gong, Lang; Li, Jie; Zhou, Qingfeng; Xu, Zhichao; Chen, Li; Zhang, Yun; Xue, Chunyi

    2017-01-01

    We identified from suckling piglets with diarrhea in China a new bat-HKU2–like porcine coronavirus (porcine enteric alphacoronavirus). The GDS04 strain of this coronavirus shares high aa identities (>90%) with the reported bat-HKU2 strains in Coronaviridae-wide conserved domains, suggesting that the GDS04 strain belongs to the same species as HKU2. PMID:28654418

  4. Rapid RNase L-driven arrest of protein synthesis in the dsRNA response without degradation of translation machinery.

    PubMed

    Donovan, Jesse; Rath, Sneha; Kolet-Mandrikov, David; Korennykh, Alexei

    2017-11-01

    Mammalian cells respond to double-stranded RNA (dsRNA) by activating a translation-inhibiting endoribonuclease, RNase L. Consensus in the field indicates that RNase L arrests protein synthesis by degrading ribosomal RNAs (rRNAs) and messenger RNAs (mRNAs). However, here we provide evidence for a different and far more efficient mechanism. By sequencing abundant RNA fragments generated by RNase L in human cells, we identify site-specific cleavage of two groups of noncoding RNAs: Y-RNAs, whose function is poorly understood, and cytosolic tRNAs, which are essential for translation. Quantitative analysis of human RNA cleavage versus nascent protein synthesis in lung carcinoma cells shows that RNase L stops global translation when tRNAs, as well as rRNAs and mRNAs, are still intact. Therefore, RNase L does not have to degrade the translation machinery to stop protein synthesis. Our data point to a rapid mechanism that transforms a subtle RNA cleavage into a cell-wide translation arrest. © 2017 Donovan et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  5. Non-nucleoside building blocks for copper-assisted and copper-free click chemistry for the efficient synthesis of RNA conjugates.

    PubMed

    Jayaprakash, K N; Peng, Chang Geng; Butler, David; Varghese, Jos P; Maier, Martin A; Rajeev, Kallanthottathil G; Manoharan, Muthiah

    2010-12-03

    Novel non-nucleoside alkyne monomers compatible with oligonucleotide synthesis were designed, synthesized, and efficiently incorporated into RNA and RNA analogues during solid-phase synthesis. These modifications allowed site-specific conjugation of ligands to the RNA oligonucleotides through copper-assisted (CuAAC) and copper-free strain-promoted azide-alkyne cycloaddition (SPAAC) reactions. The SPAAC click reactions of cyclooctyne-oligonucleotides with various classes of azido-functionalized ligands in solution phase and on solid phase were efficient and quantitative and occurred under mild reaction conditions. The SPAAC reaction provides a method for the synthesis of oligonucleotide-ligand conjugates uncontaminated with copper ions.

  6. The parable of the caveman and the Ferrari: protein synthesis and the RNA world

    PubMed Central

    Noller, Harry F.

    2017-01-01

    The basic steps of protein synthesis are carried out by the ribosome, a very large and complex ribonucleoprotein particle. In keeping with its proposed emergence from an RNA world, all three of its core mechanisms—aminoacyl-tRNA selection, catalysis of peptide bond formation and coupled translocation of mRNA and tRNA—are embodied in the properties of ribosomal RNA, while its proteins play a supportive role. This article is part of the themed issue ‘Perspectives on the ribosome’. PMID:28138073

  7. LKB1 promotes cell survival by modulating TIF-IA-mediated pre-ribosomal RNA synthesis under uridine downregulated conditions

    PubMed Central

    Liu, Xiuju; Huang, Henry; Wilkinson, Scott C.; Zhong, Diansheng; Khuri, Fadlo R.; Fu, Haian; Marcus, Adam; He, Yulong; Zhou, Wei

    2016-01-01

    We analyzed the mechanism underlying 5-aminoimidazole-4-carboxamide riboside (AICAR) mediated apoptosis in LKB1-null non-small cell lung cancer (NSCLC) cells. Metabolic profile analysis revealed depletion of the intracellular pyrimidine pool after AICAR treatment, but uridine was the only nucleotide precursor capable of rescuing this apoptosis, suggesting the involvement of RNA metabolism. Because half of RNA transcription in cancer is for pre-ribosomal RNA (rRNA) synthesis, which is suppressed by over 90% after AICAR treatment, we evaluated the role of TIF-IA-mediated rRNA synthesis. While the depletion of TIF-IA by RNAi alone promoted apoptosis in LKB1-null cells, the overexpression of a wild-type or a S636A TIF-IA mutant, but not a S636D mutant, attenuated AICAR-induced apoptosis. In LKB1-null H157 cells, pre-rRNA synthesis was not suppressed by AICAR when wild-type LKB1 was present, and cellular fractionation analysis indicated that TIF-IA quickly accumulated in the nucleus in the presence of a wild-type LKB1 but not a kinase-dead mutant. Furthermore, ectopic expression of LKB1 was capable of attenuating AICAR-induced death in AMPK-null cells. Because LKB1 promotes cell survival by modulating TIF-IA-mediated pre-rRNA synthesis, this discovery suggested that targeted depletion of uridine related metabolites may be exploited in the clinic to eliminate LKB1-null cancer cells. PMID:26506235

  8. LKB1 promotes cell survival by modulating TIF-IA-mediated pre-ribosomal RNA synthesis under uridine downregulated conditions.

    PubMed

    Liu, Fakeng; Jin, Rui; Liu, Xiuju; Huang, Henry; Wilkinson, Scott C; Zhong, Diansheng; Khuri, Fadlo R; Fu, Haian; Marcus, Adam; He, Yulong; Zhou, Wei

    2016-01-19

    We analyzed the mechanism underlying 5-aminoimidazole-4-carboxamide riboside (AICAR) mediated apoptosis in LKB1-null non-small cell lung cancer (NSCLC) cells. Metabolic profile analysis revealed depletion of the intracellular pyrimidine pool after AICAR treatment, but uridine was the only nucleotide precursor capable of rescuing this apoptosis, suggesting the involvement of RNA metabolism. Because half of RNA transcription in cancer is for pre-ribosomal RNA (rRNA) synthesis, which is suppressed by over 90% after AICAR treatment, we evaluated the role of TIF-IA-mediated rRNA synthesis. While the depletion of TIF-IA by RNAi alone promoted apoptosis in LKB1-null cells, the overexpression of a wild-type or a S636A TIF-IA mutant, but not a S636D mutant, attenuated AICAR-induced apoptosis. In LKB1-null H157 cells, pre-rRNA synthesis was not suppressed by AICAR when wild-type LKB1 was present, and cellular fractionation analysis indicated that TIF-IA quickly accumulated in the nucleus in the presence of a wild-type LKB1 but not a kinase-dead mutant. Furthermore, ectopic expression of LKB1 was capable of attenuating AICAR-induced death in AMPK-null cells. Because LKB1 promotes cell survival by modulating TIF-IA-mediated pre-rRNA synthesis, this discovery suggested that targeted depletion of uridine related metabolites may be exploited in the clinic to eliminate LKB1-null cancer cells.

  9. Detection of subgenomic mRNA of feline coronavirus by real-time polymerase chain reaction based on primer-probe energy transfer (P-sg-QPCR).

    PubMed

    Hornyák, Akos; Bálint, Adám; Farsang, Attila; Balka, Gyula; Hakhverdyan, Mikhayil; Rasmussen, Thomas Bruun; Blomberg, Jonas; Belák, Sándor

    2012-05-01

    Feline infectious peritonitis is one of the most severe devastating diseases of the Felidae. Upon the appearance of clinical signs, a cure for the infected animal is impossible. Therefore rapid and proper diagnosis for both the presence of the causative agent, feline coronavirus (FCoV) and the manifestation of feline infectious peritonitis is of paramount importance. In the present work, a novel real-time RT-PCR method is described which is able to detect FCoV and to determine simultaneously the quantity of the viral RNA. The new assay combines the M gene subgenomic messenger RNA (sg-mRNA) detection and the quantitation of the genome copies of FCoV. In order to detect the broadest spectrum of potential FCoV variants and to achieve the most accurate results in the detection ability the new assay is applying the primer-probe energy transfer (PriProET) principle. This technology was chosen since PriProET is very robust to tolerate the nucleotide substitutions in the target area. Therefore, this technology provides a very broad-range system, which is able to detect simultaneously many variants of the virus(es) even if the target genomic regions show large scale of variations. The detection specificity of the new assay was proven by positive amplification from a set of nine different FCoV strains and negative from the tested non-coronaviral targets. Examination of faecal samples of healthy young cats, organ samples of perished animals, which suffered from feline infectious peritonitis, and cat leukocytes from uncertain clinical cases were also subjected to the assay. The sensitivity of the P-sg-QPCR method was high, since as few as 10 genome copies of FCoV were detected. The quantitative sg-mRNA detection method revealed more than 10-50,000 times increase of the M gene sg-mRNA in organ materials of feline infectious peritonitis cases, compared to those of the enteric FCoV variants present in the faeces of normal, healthy cats. These results indicate the applicability of

  10. The SARS-Unique Domain (SUD) of SARS Coronavirus Contains Two Macrodomains That Bind G-Quadruplexes

    PubMed Central

    Tan, Jinzhi; Vonrhein, Clemens; Smart, Oliver S.; Bricogne, Gerard; Bollati, Michela; Kusov, Yuri; Hansen, Guido; Mesters, Jeroen R.; Schmidt, Christian L.; Hilgenfeld, Rolf

    2009-01-01

    Since the outbreak of severe acute respiratory syndrome (SARS) in 2003, the three-dimensional structures of several of the replicase/transcriptase components of SARS coronavirus (SARS-CoV), the non-structural proteins (Nsps), have been determined. However, within the large Nsp3 (1922 amino-acid residues), the structure and function of the so-called SARS-unique domain (SUD) have remained elusive. SUD occurs only in SARS-CoV and the highly related viruses found in certain bats, but is absent from all other coronaviruses. Therefore, it has been speculated that it may be involved in the extreme pathogenicity of SARS-CoV, compared to other coronaviruses, most of which cause only mild infections in humans. In order to help elucidate the function of the SUD, we have determined crystal structures of fragment 389–652 (“SUDcore”) of Nsp3, which comprises 264 of the 338 residues of the domain. Both the monoclinic and triclinic crystal forms (2.2 and 2.8 Å resolution, respectively) revealed that SUDcore forms a homodimer. Each monomer consists of two subdomains, SUD-N and SUD-M, with a macrodomain fold similar to the SARS-CoV X-domain. However, in contrast to the latter, SUD fails to bind ADP-ribose, as determined by zone-interference gel electrophoresis. Instead, the entire SUDcore as well as its individual subdomains interact with oligonucleotides known to form G-quadruplexes. This includes oligodeoxy- as well as oligoribonucleotides. Mutations of selected lysine residues on the surface of the SUD-N subdomain lead to reduction of G-quadruplex binding, whereas mutations in the SUD-M subdomain abolish it. As there is no evidence for Nsp3 entering the nucleus of the host cell, the SARS-CoV genomic RNA or host-cell mRNA containing long G-stretches may be targets of SUD. The SARS-CoV genome is devoid of G-stretches longer than 5–6 nucleotides, but more extended G-stretches are found in the 3′-nontranslated regions of mRNAs coding for certain host-cell proteins involved

  11. Interaction between the cellular protein eEF1A and the 3'-terminal stem-loop of West Nile virus genomic RNA facilitates viral minus-strand RNA synthesis.

    PubMed

    Davis, William G; Blackwell, Jerry L; Shi, Pei-Yong; Brinton, Margo A

    2007-09-01

    RNase footprinting and nitrocellulose filter binding assays were previously used to map one major and two minor binding sites for the cell protein eEF1A on the 3'(+) stem-loop (SL) RNA of West Nile virus (WNV) (3). Base substitutions in the major eEF1A binding site or adjacent areas of the 3'(+) SL were engineered into a WNV infectious clone. Mutations that decreased, as well as ones that increased, eEF1A binding in in vitro assays had a negative effect on viral growth. None of these mutations affected the efficiency of translation of the viral polyprotein from the genomic RNA, but all of the mutations that decreased in vitro eEF1A binding to the 3' SL RNA also decreased viral minus-strand RNA synthesis in transfected cells. Also, a mutation that increased the efficiency of eEF1A binding to the 3' SL RNA increased minus-strand RNA synthesis in transfected cells, which resulted in decreased synthesis of genomic RNA. These results strongly suggest that the interaction between eEF1A and the WNV 3' SL facilitates viral minus-strand synthesis. eEF1A colocalized with viral replication complexes (RC) in infected cells and antibody to eEF1A coimmunoprecipitated viral RC proteins, suggesting that eEF1A facilitates an interaction between the 3' end of the genome and the RC. eEF1A bound with similar efficiencies to the 3'-terminal SL RNAs of four divergent flaviviruses, including a tick-borne flavivirus, and colocalized with dengue virus RC in infected cells. These results suggest that eEF1A plays a similar role in RNA replication for all flaviviruses.

  12. The mechanism of montmorillonite catalysis in RNA synthesis

    NASA Astrophysics Data System (ADS)

    Joshi, Prakash

    The formation of complex prebiotic molecules on the early Earth is likely to have involved a component of mineral catalysis. Amongst the variety of clay minerals that have been investigated by us for their ability to catalyze the formation of RNA oligomers is montmorillonite. These are 2:1 layer silicates that have a wide range of chemical compositions [(Na,Ca)0.33(Al,Fe,Mg)2(Si,Al)4O10(OH)2.nH2O]. They are commonly produced by the weathering of silicic volcanic ashes to form Bentonite. Once formed, montmorillonites gradually transform to Illites at a modest pressure and temperature. Of the many samples of montmorillonite that we have experimentally examined, a selected subset has been observed to be catalytic for RNA synthesis (Joshi et. al., 2009; Aldersley et al., 2011). Those that have been observed to be excellent catalysts come from a restricted range of elemental compositions. The recent identification of phyllosilicates including montmorillonite on Mars (Bishop et al., 2008) raises the possibility that such processes may have taken place there too. The extent of catalysis depended not only upon the magnitude of the negative charge on the montmorillonite lattice and the number of cations associated with it, but also on the pH at which the reaction is promoted. The isotherm and catalysis studies were extended to provide binding information and catalytic outcomes over a wide pH range. When cations in raw montmorillonite are completely replaced by sodium ions, the resulting Na+-montmorillonite does not catalyze oligomer formation because the ions saturate the interlayer between the platelets of montmorillonite, which blocks the binding of the activated monomers. Acid washed montmorillonite titrated to pH 6-8 with alkali metal ions, serves as the model catalyst for this RNA synthesis (Aldersley et. al., 2011). The optimal binding occurred in the region of maximal oligomer formation. X-ray diffraction studies revealed changes in layer separations of

  13. Antibacterial activity of lichen secondary metabolite usnic acid is primarily caused by inhibition of RNA and DNA synthesis.

    PubMed

    Maciąg-Dorszyńska, Monika; Węgrzyn, Grzegorz; Guzow-Krzemińska, Beata

    2014-04-01

    Usnic acid, a compound produced by various lichen species, has been demonstrated previously to inhibit growth of different bacteria and fungi; however, mechanism of its antimicrobial activity remained unknown. In this report, we demonstrate that usnic acid causes rapid and strong inhibition of RNA and DNA synthesis in Gram-positive bacteria, represented by Bacillus subtilis and Staphylococcus aureus, while it does not inhibit production of macromolecules (DNA, RNA, and proteins) in Escherichia coli, which is resistant to even high doses of this compound. However, we also observed slight inhibition of RNA synthesis in a Gram-negative bacterium, Vibrio harveyi. Inhibition of protein synthesis in B. subtilis and S. aureus was delayed, which suggest indirect action (possibly through impairment of transcription) of usnic acid on translation. Interestingly, DNA synthesis was halted rapidly in B. subtilis and S. aureus, suggesting interference of usnic acid with elongation of DNA replication. We propose that inhibition of RNA synthesis may be a general mechanism of antibacterial action of usnic acid, with additional direct mechanisms, such as impairment of DNA replication in B. subtilis and S. aureus. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  14. Synthesis and RNA polymerase incorporation of the degenerate ribonucleotide analogue rPTP.

    PubMed Central

    Moriyama, K; Negishi, K; Briggs, M S; Smith, C L; Hill, F; Churcher, M J; Brown, D M; Loakes, D

    1998-01-01

    The synthesis and enzymatic incorporation into RNA of the hydrogen bond degenerate nucleoside analogue 6-(beta-d-ribofuranosyl)-3, 4-dihydro-8H-pyrimido[4,5-c]-[1,2]oxazin-7-one (P) is described. The 5'-triphosphate of this analogue is readily incorporated by T3, T7 and SP6 RNA polymerases into RNA transcripts, being best incorporated in place of UTP, but also in place of CTP. When all the uridine residues in an HIV-1 TAR RNA transcript are replaced by P the transcript has similar characteristics to the wild-type TAR RNA, as demonstrated by similar melting temperatures and CD spectra. The P-substituted TAR transcript binds to the Tat peptide ADP-1 with only 4-fold lowered efficiency compared with wild-type TAR. PMID:9547267

  15. Synthesis and RNA polymerase incorporation of the degenerate ribonucleotide analogue rPTP.

    PubMed

    Moriyama, K; Negishi, K; Briggs, M S; Smith, C L; Hill, F; Churcher, M J; Brown, D M; Loakes, D

    1998-05-01

    The synthesis and enzymatic incorporation into RNA of the hydrogen bond degenerate nucleoside analogue 6-(beta-d-ribofuranosyl)-3, 4-dihydro-8H-pyrimido[4,5-c]-[1,2]oxazin-7-one (P) is described. The 5'-triphosphate of this analogue is readily incorporated by T3, T7 and SP6 RNA polymerases into RNA transcripts, being best incorporated in place of UTP, but also in place of CTP. When all the uridine residues in an HIV-1 TAR RNA transcript are replaced by P the transcript has similar characteristics to the wild-type TAR RNA, as demonstrated by similar melting temperatures and CD spectra. The P-substituted TAR transcript binds to the Tat peptide ADP-1 with only 4-fold lowered efficiency compared with wild-type TAR.

  16. Growth, oxygen consumption, and protein and RNA synthesis rates in the yolk sac larvae of the African catfish (Clarias gariepinus).

    PubMed

    Smith, Richard W; Ottema, Colin

    2006-03-01

    Rapidly growing African catfish yolk sac larvae were investigated during the first 22 h after hatching. Body compartment protein concentration increased fourfold yet oxygen consumption remained constant (mean=21.3 +/- 3.2 nmol O2 mg(-1) protein h(-1)), suggesting fast growth results mainly from yolk sac protein absorption. The protein synthesis rates at 1-2 and 5-6 h also equaled the highest conceivable rates of muscle protein synthesis; 11.6-11.9% and 7.4-7.9% day(-1), respectively. Therefore the corresponding energetic costs of protein synthesis were almost the theoretical minimum; 13.0 +/- 1.7-16.3 +/- 2.8 micromol O2 mg(-1) protein synthesised. Total protein synthesis expenditure (74.5-77.7 micromol O2 g(-1) protein h(-1)) was also less than other yolk sac larvae. These protein synthesis rates resulted from high RNA concentrations (113.2 +/- 3.4 microg RNA mg(-1) protein) and were also correlated with RNA translational efficiency. High translational efficiency (1 h; 1.2+/-0.1 mg protein synthesised microg(-1) RNA day(-1)) equaled high synthesis rate (36.8 +/- 5.4 microg RNA microg(-1) DNA day(-1)) and both declined over 22 h. This investigation suggests rapid growth combines growth efficiency and compensatory energy partitioning. This accommodates the ontogenetic and phylogenetic standpoints imposed by energy budget limitations.

  17. The SARS-Coronavirus papain-like protease: Structure, function and inhibition by designed antiviral compounds

    PubMed Central

    Baez-Santos, Yahira M.; St. John, Sarah E.; Mesecar, Andrew D.

    2018-01-01

    Over ten years have passed since the deadly human coronavirus that causes severe acute respiratory syndrome (SARS-CoV) emerged from the Guangdong Province of China. Despite the fact that the SARS-CoV pandemic infected over 8,500 individuals, claimed over 800 lives and cost billions of dollars in economic loss worldwide, there still are no clinically approved antiviral drugs, vaccines or monoclonal antibody therapies to treat SARS-CoV infections. The recent emergence of the deadly human coronavirus that causes Middle East respiratory syndrome (MERS-CoV) is a sobering reminder that new and deadly coronaviruses can emerge at any time with the potential to become pandemics. Therefore, the continued development of therapeutic and prophylactic countermeasures to potentially deadly coronaviruses is warranted. The coronaviral proteases, papain-like protease (PLpro) and 3C-like protease (3CLpro), are attractive antiviral drug targets because they are essential for coronaviral replication. Although the primary function of PLpro and 3CLpro are to process the viral polyprotein in a coordinated manner, PLpro has the additional function of stripping ubiquitin and ISG15 from host-cell proteins to aid coronaviruses in their evasion of the host innate immune responses. Therefore, targeting PLpro with antiviral drugs may have an advantage in not only inhibiting viral replication but also inhibiting the dysregulation of signaling cascades in infected cells that may lead to cell death in surrounding, uninfected cells. This review provides an up-to-date discussion on the SARS-CoV papain-like protease including a brief overview of the SARS-CoV genome and replication followed by a more in-depth discussion on the structure and catalytic mechanism of SARS-CoV PLpro, the multiple cellular functions of SARS-CoV PLpro, the inhibition of SARS-CoV PLpro by small molecule inhibitors, and the prospect of inhibiting papain-like protease from other coronaviruses. This paper forms part of a series

  18. Evidence for an Ancestral Association of Human Coronavirus 229E with Bats

    PubMed Central

    Corman, Victor Max; Baldwin, Heather J.; Tateno, Adriana Fumie; Zerbinati, Rodrigo Melim; Annan, Augustina; Owusu, Michael; Nkrumah, Evans Ewald; Maganga, Gael Darren; Oppong, Samuel; Adu-Sarkodie, Yaw; Vallo, Peter; da Silva Filho, Luiz Vicente Ribeiro Ferreira; Leroy, Eric M.; Thiel, Volker; van der Hoek, Lia; Poon, Leo L. M.; Tschapka, Marco

    2015-01-01

    ABSTRACT We previously showed that close relatives of human coronavirus 229E (HCoV-229E) exist in African bats. The small sample and limited genomic characterizations have prevented further analyses so far. Here, we tested 2,087 fecal specimens from 11 bat species sampled in Ghana for HCoV-229E-related viruses by reverse transcription-PCR (RT-PCR). Only hipposiderid bats tested positive. To compare the genetic diversity of bat viruses and HCoV-229E, we tested historical isolates and diagnostic specimens sampled globally over 10 years. Bat viruses were 5- and 6-fold more diversified than HCoV-229E in the RNA-dependent RNA polymerase (RdRp) and spike genes. In phylogenetic analyses, HCoV-229E strains were monophyletic and not intermixed with animal viruses. Bat viruses formed three large clades in close and more distant sister relationships. A recently described 229E-related alpaca virus occupied an intermediate phylogenetic position between bat and human viruses. According to taxonomic criteria, human, alpaca, and bat viruses form a single CoV species showing evidence for multiple recombination events. HCoV-229E and the alpaca virus showed a major deletion in the spike S1 region compared to all bat viruses. Analyses of four full genomes from 229E-related bat CoVs revealed an eighth open reading frame (ORF8) located at the genomic 3′ end. ORF8 also existed in the 229E-related alpaca virus. Reanalysis of HCoV-229E sequences showed a conserved transcription regulatory sequence preceding remnants of this ORF, suggesting its loss after acquisition of a 229E-related CoV by humans. These data suggested an evolutionary origin of 229E-related CoVs in hipposiderid bats, hypothetically with camelids as intermediate hosts preceding the establishment of HCoV-229E. IMPORTANCE The ancestral origins of major human coronaviruses (HCoVs) likely involve bat hosts. Here, we provide conclusive genetic evidence for an evolutionary origin of the common cold virus HCoV-229E in

  19. Severe acute respiratory syndrome coronavirus as an agent of emerging and reemerging infection.

    PubMed

    Cheng, Vincent C C; Lau, Susanna K P; Woo, Patrick C Y; Yuen, Kwok Yung

    2007-10-01

    Before the emergence of severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) in 2003, only 12 other animal or human coronaviruses were known. The discovery of this virus was soon followed by the discovery of the civet and bat SARS-CoV and the human coronaviruses NL63 and HKU1. Surveillance of coronaviruses in many animal species has increased the number on the list of coronaviruses to at least 36. The explosive nature of the first SARS epidemic, the high mortality, its transient reemergence a year later, and economic disruptions led to a rush on research of the epidemiological, clinical, pathological, immunological, virological, and other basic scientific aspects of the virus and the disease. This research resulted in over 4,000 publications, only some of the most representative works of which could be reviewed in this article. The marked increase in the understanding of the virus and the disease within such a short time has allowed the development of diagnostic tests, animal models, antivirals, vaccines, and epidemiological and infection control measures, which could prove to be useful in randomized control trials if SARS should return. The findings that horseshoe bats are the natural reservoir for SARS-CoV-like virus and that civets are the amplification host highlight the importance of wildlife and biosecurity in farms and wet markets, which can serve as the source and amplification centers for emerging infections.

  20. Severe Acute Respiratory Syndrome Coronavirus as an Agent of Emerging and Reemerging Infection

    PubMed Central

    Cheng, Vincent C. C.; Lau, Susanna K. P.; Woo, Patrick C. Y.; Yuen, Kwok Yung

    2007-01-01

    Before the emergence of severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) in 2003, only 12 other animal or human coronaviruses were known. The discovery of this virus was soon followed by the discovery of the civet and bat SARS-CoV and the human coronaviruses NL63 and HKU1. Surveillance of coronaviruses in many animal species has increased the number on the list of coronaviruses to at least 36. The explosive nature of the first SARS epidemic, the high mortality, its transient reemergence a year later, and economic disruptions led to a rush on research of the epidemiological, clinical, pathological, immunological, virological, and other basic scientific aspects of the virus and the disease. This research resulted in over 4,000 publications, only some of the most representative works of which could be reviewed in this article. The marked increase in the understanding of the virus and the disease within such a short time has allowed the development of diagnostic tests, animal models, antivirals, vaccines, and epidemiological and infection control measures, which could prove to be useful in randomized control trials if SARS should return. The findings that horseshoe bats are the natural reservoir for SARS-CoV-like virus and that civets are the amplification host highlight the importance of wildlife and biosecurity in farms and wet markets, which can serve as the source and amplification centers for emerging infections. PMID:17934078

  1. [Prevalence and clinical characteristics of coronavirus NL63 infection in children hospitalized for acute lower respiratory tract infections in Changsha].

    PubMed

    Zhang, Fei; Zhang, Bing; Xie, Zhi-Ping; Gao, Han-Chun; Zhao, Xin; Zhong, Li-Li; Zhou, Qiong-Hua; Hou, Yun-De; Duan, Zhao-Jun

    2012-04-01

    The main objective of this study was to explore the prevalence and clinical characteristics of human coronavirus NL63 infection in hospitalized children with acute lower respiratory tract infection (ALRTI) in Changsha. Nasopharyngeal aspirates (NPA) samples were collected from 1185 hospitalized children with ALRTI at the People's Hospital of Hunan province, between September 2008 and October 2010. Reverse transcriptase polymerase chain reaction (RT-PCR) was employed to screen for coronavirus NL63, which is a 255 bp fragment of a part of N gene. All positive amplification products were confirmed by sequencing and compared with those in GenBank. The overall frequency of coronavirus NL63 infection was 0.8%, 6 (60%) out of the coronavirus NL63 positive patients were detected in summer, 2 in autumn, 1 in spring and winter, respectively. The patients were from 2 months to two and a half years old. The clinical diagnosis was bronchopneumonia (60%), bronchiolitis (30%), and acute laryngotracheal bronchitis (10%). Four of the 10 cases had critical illness, 4 cases had underlying diseases, and 7 cases had mixed infection with other viruses. The homogeneity of coronavirus NL63 with those published in the GenBank at nucleotide levels was 97%-100%. Coronavirus NL63 infection exists in hospitalized children with acute lower respiratory tract infection in Changsha. Coronavirus NL63 infections are common in children under 3 years of age. There is significant difference in the infection rate between the boys and the girls: the boys had higher rate than the girls. The peak of prevalence of the coronavirus NL63 was in summer. A single genetic lineage of coronavirus NL63 was revealed in human subjects in Changsha. Coronavirus NL63 may also be one of the lower respiratory pathogen in China.

  2. Osteoblast fibronectin mRNA, protein synthesis, and matrix are unchanged after exposure to microgravity

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Gilbertson, V.

    1999-01-01

    The well-defined osteoblast line, MC3T3-E1 was used to examine fibronectin (FN) mRNA levels, protein synthesis, and extracellular FN matrix accumulation after growth activation in spaceflight. These osteoblasts produce FN extracellular matrix (ECM) known to regulate adhesion, differentiation, and function in adherent cells. Changes in bone ECM and osteoblast cell shape occur in spaceflight. To determine whether altered FN matrix is a factor in causing these changes in spaceflight, quiescent osteoblasts were launched into microgravity and were then sera activated with and without a 1-gravity field. Synthesis of FN mRNA, protein, and matrix were measured after activation in microgravity. FN mRNA synthesis is significantly reduced in microgravity (0-G) when compared to ground (GR) osteoblasts flown in a centrifuge simulating earth's gravity (1-G) field 2.5 h after activation. However, 27.5 h after activation there were no significant differences in mRNA synthesis. A small but significant reduction of FN protein was found in the 0-G samples 2.5 h after activation. Total FN protein 27.5 h after activation showed no significant difference between any of the gravity conditions, however, there was a fourfold increase in absolute amount of protein synthesized during the incubation. Using immunofluorescence, we found no significant differences in the amount or in the orientation of the FN matrix after 27.5 h in microgravity. These results demonstrate that FN is made by sera-activated osteoblasts even during exposure to microgravity. These data also suggest that after a total period of 43 h of spaceflight FN transcription, translation, or altered matrix assembly is not responsible for the altered cell shape or altered matrix formation of osteoblasts.

  3. Inactivation of surrogate coronaviruses on hard surfaces by health care germicides.

    PubMed

    Hulkower, Rachel L; Casanova, Lisa M; Rutala, William A; Weber, David J; Sobsey, Mark D

    2011-06-01

    In the 2003 severe acute respiratory syndrome outbreak, finding viral nucleic acids on hospital surfaces suggested surfaces could play a role in spread in health care environments. Surface disinfection may interrupt transmission, but few data exist on the effectiveness of health care germicides against coronaviruses on surfaces. The efficacy of health care germicides against 2 surrogate coronaviruses, mouse hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV), was tested using the quantitative carrier method on stainless steel surfaces. Germicides were o-phenylphenol/p-tertiary amylphenol) (a phenolic), 70% ethanol, 1:100 sodium hypochlorite, ortho-phthalaldehyde (OPA), instant hand sanitizer (62% ethanol), and hand sanitizing spray (71% ethanol). After 1-minute contact time, for TGEV, there was a log(10) reduction factor of 3.2 for 70% ethanol, 2.0 for phenolic, 2.3 for OPA, 0.35 for 1:100 hypochlorite, 4.0 for 62% ethanol, and 3.5 for 71% ethanol. For MHV, log(10) reduction factors were 3.9 for 70% ethanol, 1.3 for phenolic, 1.7 for OPA, 0.62 for 1:100 hypochlorite, 2.7 for 62% ethanol, and 2.0 for 71% ethanol. Only ethanol reduced infectivity of the 2 coronaviruses by >3-log(10) after 1 minute. Germicides must be chosen carefully to ensure they are effective against viruses such as severe acute respiratory syndrome coronavirus. Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  4. Identification of Aminopeptidase N as a Cellular Receptor for Human Coronavirus-229E

    DTIC Science & Technology

    1992-05-12

    hemagglutinating encephalomyelitis virus (HEV), canine coronavirus (CCV), cat FIPV and feline enteric corona virus (FECV), human CVLPs, mouse...While the cat , dog and pig serve as natural hosts for the other coronavirus group 1 viruses , feline infectious peritonitis virus (FIPV), canine...3 2 . Virus Receptors ••••••••.••••••.....•................ 20 3. Viruses Which Cause Common Colds

  5. Identification of a broad-spectrum inhibitor of virus RNA synthesis: validation of a prototype virus-based approach

    PubMed Central

    Filone, Claire Marie; Hodges, Erin N.; Honeyman, Brian; Bushkin, G. Guy; Boyd, Karla; Platt, Andrew; Ni, Feng; Strom, Kyle; Hensley, Lisa; Snyder, John K.; Connor, John H.

    2013-01-01

    There are no approved therapeutics for the most deadly nonsegmented negative-strand (NNS) RNA viruses, including Ebola (EBOV). To identify new chemical scaffolds for development of broad-spectrum antivirals, we undertook a prototype-based lead identification screen. Using the prototype NNS virus, vesicular stomatitis virus (VSV), multiple inhibitory compounds were identified. Three compounds were investigated for broad-spectrum activity, and inhibited EBOV infection. The most potent, CMLDBU3402, was selected for further study. CMLDBU3402 did not show significant activity against segmented negative-strand RNA viruses suggesting proscribed broad-spectrum activity. Mechanistic analysis indicated that CMLDBU3402 blocked VSV viral RNA synthesis and inhibited EBOV RNA transcription, demonstrating a consistent mechanism of action against genetically distinct viruses. The identification of this chemical backbone as a broad-spectrum inhibitor of viral RNA synthesis offers significant potential for the development of new therapies for highly pathogenic viruses. PMID:23521799

  6. DNA polymerase-α regulates type I interferon activation through cytosolic RNA:DNA synthesis

    PubMed Central

    Starokadomskyy, Petro; Gemelli, Terry; Rios, Jonathan J.; Xing, Chao; Wang, Richard C.; Li, Haiying; Pokatayev, Vladislav; Dozmorov, Igor; Khan, Shaheen; Miyata, Naoteru; Fraile, Guadalupe; Raj, Prithvi; Xu, Zhe; Xu, Zigang; Ma, Lin; Lin, Zhimiao; Wang, Huijun; Yang, Yong; Ben-Amitai, Dan; Orenstein, Naama; Mussaffi, Huda; Baselga, Eulalia; Tadini, Gianluca; Grunebaum, Eyal; Sarajlija, Adrijan; Krzewski, Konrad; Wakeland, Edward K.; Yan, Nan; de la Morena, Maria Teresa; Zinn, Andrew R.; Burstein, Ezra

    2016-01-01

    Aberrant nucleic acids generated during viral replication are the main trigger for antiviral immunity, and mutations disrupting nucleic acid metabolism can lead to autoinflammatory disorders. Here we investigated the etiology of X-linked reticulate pigmentary disorder (XLPDR), a primary immunodeficiency with autoinflammatory features. We discovered that XLPDR is caused by an intronic mutation that disrupts expression of POLA1, the gene encoding the catalytic subunit of DNA polymerase-α. Unexpectedly, POLA1 deficiency results in increased type I interferon production. This enzyme is necessary for RNA:DNA primer synthesis during DNA replication and strikingly, POLA1 is also required for the synthesis of cytosolic RNA:DNA, which directly modulates interferon activation. Altogether, this work identified POLA1 as a critical regulator of the type I interferon response. PMID:27019227

  7. Enzymatic synthesis of random sequences of RNA and RNA analogues by DNA polymerase theta mutants for the generation of aptamer libraries.

    PubMed

    Randrianjatovo-Gbalou, Irina; Rosario, Sandrine; Sismeiro, Odile; Varet, Hugo; Legendre, Rachel; Coppée, Jean-Yves; Huteau, Valérie; Pochet, Sylvie; Delarue, Marc

    2018-05-21

    Nucleic acid aptamers, especially RNA, exhibit valuable advantages compared to protein therapeutics in terms of size, affinity and specificity. However, the synthesis of libraries of large random RNAs is still difficult and expensive. The engineering of polymerases able to directly generate these libraries has the potential to replace the chemical synthesis approach. Here, we start with a DNA polymerase that already displays a significant template-free nucleotidyltransferase activity, human DNA polymerase theta, and we mutate it based on the knowledge of its three-dimensional structure as well as previous mutational studies on members of the same polA family. One mutant exhibited a high tolerance towards ribonucleotides (NTPs) and displayed an efficient ribonucleotidyltransferase activity that resulted in the assembly of long RNA polymers. HPLC analysis and RNA sequencing of the products were used to quantify the incorporation of the four NTPs as a function of initial NTP concentrations and established the randomness of each generated nucleic acid sequence. The same mutant revealed a propensity to accept other modified nucleotides and to extend them in long fragments. Hence, this mutant can deliver random natural and modified RNA polymers libraries ready to use for SELEX, with custom lengths and balanced or unbalanced ratios.

  8. The SARS-coronavirus papain-like protease: structure, function and inhibition by designed antiviral compounds.

    PubMed

    Báez-Santos, Yahira M; St John, Sarah E; Mesecar, Andrew D

    2015-03-01

    Over 10 years have passed since the deadly human coronavirus that causes severe acute respiratory syndrome (SARS-CoV) emerged from the Guangdong Province of China. Despite the fact that the SARS-CoV pandemic infected over 8500 individuals, claimed over 800 lives and cost billions of dollars in economic loss worldwide, there still are no clinically approved antiviral drugs, vaccines or monoclonal antibody therapies to treat SARS-CoV infections. The recent emergence of the deadly human coronavirus that causes Middle East respiratory syndrome (MERS-CoV) is a sobering reminder that new and deadly coronaviruses can emerge at any time with the potential to become pandemics. Therefore, the continued development of therapeutic and prophylactic countermeasures to potentially deadly coronaviruses is warranted. The coronaviral proteases, papain-like protease (PLpro) and 3C-like protease (3CLpro), are attractive antiviral drug targets because they are essential for coronaviral replication. Although the primary function of PLpro and 3CLpro are to process the viral polyprotein in a coordinated manner, PLpro has the additional function of stripping ubiquitin and ISG15 from host-cell proteins to aid coronaviruses in their evasion of the host innate immune responses. Therefore, targeting PLpro with antiviral drugs may have an advantage in not only inhibiting viral replication but also inhibiting the dysregulation of signaling cascades in infected cells that may lead to cell death in surrounding, uninfected cells. This review provides an up-to-date discussion on the SARS-CoV papain-like protease including a brief overview of the SARS-CoV genome and replication followed by a more in-depth discussion on the structure and catalytic mechanism of SARS-CoV PLpro, the multiple cellular functions of SARS-CoV PLpro, the inhibition of SARS-CoV PLpro by small molecule inhibitors, and the prospect of inhibiting papain-like protease from other coronaviruses. This paper forms part of a series of

  9. α-Amanitin-Resistant Viral RNA Synthesis in Nuclei Isolated from Nuclear Polyhedrosis Virus-Infected Heliothis zea Larvae and Spodoptera frugiperda Cells

    PubMed Central

    Grula, Marjori A.; Buller, Patricia L.; Weaver, Robert F.

    1981-01-01

    [3H]RNA was synthesized in nuclei isolated at various times postinfection from the fat bodies of Heliothis zea larvae infected with H. zea nuclear polyhedrosis virus and from cultured Spodoptera frugiperda cells infected with Autographa californica nuclear polyhedrosis virus. To detect virus-specific RNA synthesis, the [3H]RNA was hybridized to denatured viral DNA immobilized on nitrocellulose filters. Nuclear polyhedrosis virus-specific RNA synthesis in the infected nuclei isolated from H. zea larval fat bodies and S. frugiperda cells was only inhibited 20 to 25% by concentrations of α-amanitin sufficient to inhibit the host RNA polymerase II. In addition, a productive nuclear polyhedrosis virus infection was obtained in S. frugiperda cells grown in the presence of an α-amanitin concentration that inhibited 90% of the cellular RNA polymerase II activity. The cellular RNA polymerase II enzyme remained sensitive to α-amanitin during infection, and there was no evidence that a virus-coded, α-amanitin-resistant enzyme was synthesized after the onset of infection. The data suggest that the bulk of nuclear polyhedrosis virus-specific RNA synthesis in isolated nuclei is transcribed by an enzyme other than the host RNA polymerase II. PMID:16789208

  10. Severe Acute Respiratory Syndrome-Associated Coronavirus Vaccines Formulated with Delta Inulin Adjuvants Provide Enhanced Protection while Ameliorating Lung Eosinophilic Immunopathology

    PubMed Central

    Honda-Okubo, Yoshikazu; Barnard, Dale; Ong, Chun Hao; Peng, Bi-Hung; Tseng, Chien-Te Kent

    2014-01-01

    ABSTRACT Although the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) epidemic was controlled by nonvaccine measures, coronaviruses remain a major threat to human health. The design of optimal coronavirus vaccines therefore remains a priority. Such vaccines present major challenges: coronavirus immunity often wanes rapidly, individuals needing to be protected include the elderly, and vaccines may exacerbate rather than prevent coronavirus lung immunopathology. To address these issues, we compared in a murine model a range of recombinant spike protein or inactivated whole-virus vaccine candidates alone or adjuvanted with either alum, CpG, or Advax, a new delta inulin-based polysaccharide adjuvant. While all vaccines protected against lethal infection, addition of adjuvant significantly increased serum neutralizing-antibody titers and reduced lung virus titers on day 3 postchallenge. Whereas unadjuvanted or alum-formulated vaccines were associated with significantly increased lung eosinophilic immunopathology on day 6 postchallenge, this was not seen in mice immunized with vaccines formulated with delta inulin adjuvant. Protection against eosinophilic immunopathology by vaccines containing delta inulin adjuvants correlated better with enhanced T-cell gamma interferon (IFN-γ) recall responses rather than reduced interleukin-4 (IL-4) responses, suggesting that immunopathology predominantly reflects an inadequate vaccine-induced Th1 response. This study highlights the critical importance for development of effective and safe coronavirus vaccines of selection of adjuvants based on the ability to induce durable IFN-γ responses. IMPORTANCE Coronaviruses such as SARS-CoV and Middle East respiratory syndrome-associated coronavirus (MERS-CoV) cause high case fatality rates and remain major human public health threats, creating a need for effective vaccines. While coronavirus antigens that induce protective neutralizing antibodies have been identified

  11. Initiation of viral RNA-dependent RNA polymerization.

    PubMed

    van Dijk, Alberdina A; Makeyev, Eugene V; Bamford, Dennis H

    2004-05-01

    This review summarizes the combined insights from recent structural and functional studies of viral RNA-dependent RNA polymerases (RdRPs) with the primary focus on the mechanisms of initiation of RNA synthesis. Replication of RNA viruses has traditionally been approached using a combination of biochemical and genetic methods. Recently, high-resolution structures of six viral RdRPs have been determined. For three RdRPs, enzyme complexes with metal ions, single-stranded RNA and/or nucleoside triphosphates have also been solved. These advances have expanded our understanding of the molecular mechanisms of viral RNA synthesis and facilitated further RdRP studies by informed site-directed mutagenesis. What transpires is that the basic polymerase right hand shape provides the correct geometrical arrangement of substrate molecules and metal ions at the active site for the nucleotidyl transfer catalysis, while distinct structural elements have evolved in the different systems to ensure efficient initiation of RNA synthesis. These elements feed the template, NTPs and ions into the catalytic cavity, correctly position the template 3' terminus, transfer the products out of the catalytic site and orchestrate the transition from initiation to elongation.

  12. AKAP3 synthesis is mediated by RNA binding proteins and PKA signaling during mouse spermiogenesis.

    PubMed

    Xu, Kaibiao; Yang, Lele; Zhao, Danyun; Wu, Yaoyao; Qi, Huayu

    2014-06-01

    Mammalian spermatogenesis is regulated by coordinated gene expression in a spatiotemporal manner. The spatiotemporal regulation of major sperm proteins plays important roles during normal development of the male gamete, of which the underlying molecular mechanisms are poorly understood. A-kinase anchoring protein 3 (AKAP3) is one of the major components of the fibrous sheath of the sperm tail that is formed during spermiogenesis. In the present study, we analyzed the expression of sperm-specific Akap3 and the potential regulatory factors of its protein synthesis during mouse spermiogenesis. Results showed that the transcription of Akap3 precedes its protein synthesis by about 2 wk. Nascent AKAP3 was found to form protein complex with PKA and RNA binding proteins (RBPs), including PIWIL1, PABPC1, and NONO, as revealed by coimmunoprecipitation and protein mass spectrometry. RNA electrophoretic gel mobility shift assay showed that these RBPs bind sperm-specific mRNAs, of which proteins are synthesized during the elongating stage of spermiogenesis. Biochemical and cell biological experiments demonstrated that PIWIL1, PABPC1, and NONO interact with each other and colocalize in spermatids' RNA granule, the chromatoid body. In addition, NONO was found in extracytoplasmic granules in round spermatids, whereas PIWIL1 and PABPC1 were diffusely localized in cytoplasm of elongating spermatids, indicating their participation at different steps of mRNA metabolism during spermatogenesis. Interestingly, type I PKA subunits colocalize with PIWIL1 and PABPC1 in the cytoplasm of elongating spermatids and cosediment with the RBPs in polysomal fractions on sucrose gradients. Further biochemical analyses revealed that activation of PKA positively regulates AKAP3 protein synthesis without changing its mRNA level in elongating spermatids. Taken together, these results indicate that PKA signaling directly participates in the regulation of protein translation in postmeiotic male germ cells

  13. West nile virus infections suppress early viral RNA synthesis and avoid inducing the cell stress granule response.

    PubMed

    Courtney, S C; Scherbik, S V; Stockman, B M; Brinton, M A

    2012-04-01

    West Nile virus (WNV) recently became endemic in the United States and is a significant cause of human morbidity and mortality. Natural WNV strain infections do not induce stress granules (SGs), while W956IC (a lineage 2/1 chimeric WNV infectious clone) virus infections produce high levels of early viral RNA and efficiently induce SGs through protein kinase R (PKR) activation. Additional WNV chimeric viruses made by replacing one or more W956IC genes with the lineage 1 Eg101 equivalent in the W956IC backbone were analyzed. The Eg-NS4b+5, Eg-NS1+3+4a, and Eg-NS1+4b+5 chimeras produced low levels of viral RNA at early times of infection and inefficiently induced SGs, suggesting the possibility that interactions between viral nonstructural proteins and/or between viral nonstructural proteins and cell proteins are involved in suppressing early viral RNA synthesis and membrane remodeling during natural WNV strain infections. Detection of exposed viral double-stranded RNA (dsRNA) in W956IC-infected cells suggested that the enhanced early viral RNA synthesis surpassed the available virus-induced membrane protection and allowed viral dsRNA to activate PKR.

  14. Synthesis, base pairing and structure studies of geranylated RNA.

    PubMed

    Wang, Rui; Vangaveti, Sweta; Ranganathan, Srivathsan V; Basanta-Sanchez, Maria; Haruehanroengra, Phensinee; Chen, Alan; Sheng, Jia

    2016-07-27

    Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. 2-Thiouridine geranylation is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, such as Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella Typhimurium The geranylated residues are located in the first anticodon position of tRNAs specific for lysine, glutamine and glutamic acid. This big hydrophobic terpene functional group affects the codon recognition patterns and reduces frameshifting errors during translation. We aimed to systematically study the structure, function and biosynthesis mechanism of this geranylation pathway, as well as answer the question of why nature uses such a hydrophobic modification in hydrophilic RNA systems. Recently, we have synthesized the deoxy-analog of S-geranyluridine and showed the geranylated T-G pair is much stronger than the geranylated T-A pair and other mismatched pairs in the B-form DNA duplex context, which is consistent with the observation that the geranylated tRNA(Glu) UUC recognizes GAG more efficiently than GAA. In this manuscript we report the synthesis and base pairing specificity studies of geranylated RNA oligos. We also report extensive molecular simulation studies to explore the structural features of the geranyl group in the context of A-form RNA and its effect on codon-anticodon interaction during ribosome binding. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Rigid 2',4'-difluororibonucleosides: synthesis, conformational analysis, and incorporation into nascent RNA by HCV polymerase.

    PubMed

    Martínez-Montero, Saúl; Deleavey, Glen F; Kulkarni, Anupriya; Martín-Pintado, Nerea; Lindovska, Petra; Thomson, Michael; González, Carlos; Götte, Matthias; Damha, Masad J

    2014-06-20

    We report on the synthesis and conformational properties of 2'-deoxy-2',4'-difluorouridine (2',4'-diF-rU) and cytidine (2',4'-diF-rC) nucleosides. NMR analysis and quantum mechanical calculations show that the strong stereoelectronic effects induced by the two fluorines essentially "lock" the conformation of the sugar in the North region of the pseudorotational cycle. Our studies also demonstrate that NS5B HCV RNA polymerase was able to accommodate 2',4'-diF-rU 5'-triphosphate (2',4'-diF-rUTP) and to link the monophosphate to the RNA primer strand. 2',4'-diF-rUTP inhibited RNA synthesis in dinucleotide-primed reactions, although with relatively high half-maximal inhibitory concentrations (IC50 > 50 μM). 2',4'-diF-rU/C represents rare examples of "locked" ribonucleoside mimics that lack a bicyclic ring structure.

  16. Anti-influenza virus activity of a salcomine derivative mediated by inhibition of viral RNA synthesis.

    PubMed

    Takizawa, Naoki; Kimura, Tomoyuki; Watanabe, Takumi; Shibasaki, Masakatsu

    2018-06-01

    Influenza virus infection is a major threat to global health. Although vaccines and anti-influenza virus drugs are available, annual influenza virus epidemics result in severe illness, and an influenza pandemic occurs every 20-30 years. To identify candidate anti-influenza virus compounds, we screened approximately 5,000 compounds in an in-house library. We identified MZ7465, a salcomine derivative, as a potent inhibitor of influenza virus propagation. We analyzed the antiviral propagation mechanism of the hit compound by determining the amounts of viral proteins and RNA in infected cells treated with or without the hit compound. Treatment of infected cells with MZ7465 decreased both viral protein and RNA synthesis. In addition, an in vitro assay showed that viral RNA synthesis was directly inhibited by MZ7465. These results suggest that salcomine and its derivatives are potential candidates for the treatment of influenza virus infections.

  17. Glycan shield and epitope masking of a coronavirus spike protein observed by cryo-electron microscopy

    PubMed Central

    Walls, Alexandra C.; Tortorici, M. Alejandra; Frenz, Brandon; Snijder, Joost; Li, Wentao; Rey, Félix A.; DiMaio, Frank; Bosch, Berend-Jan; Veesler, David

    2017-01-01

    The threat of a major coronavirus pandemic urges the development of suitable strategies to combat these pathogens. HCoV-NL63 is an α-coronavirus that can cause severe lower respiratory tract infections requiring hospitalization. We report here the 3.4 Å resolution cryo-electron microscopy reconstruction of the HCoV-NL63 coronavirus spike glycoprotein trimer, which is the conformational machine responsible for entry into host cells and the sole target of neutralizing antibodies during infection. The map resolves the extensive glycan shield obstructing the protein surface and, in combination with mass-spectrometry, provides a structural framework to understand accessibility to antibodies. The structure also reveals a remarkable modular architecture of the receptor-binding subunit and the complete architecture of the fusion machinery including the triggering loop and the C-terminal domains, which contribute to anchoring the trimer to the viral membrane. Our data further suggest that HCoV-NL63 and other coronaviruses use molecular trickery, based on masking of epitopes with glycans and activating conformational changes, to evade the immune system of infected hosts. PMID:27617430

  18. A Novel Chemical Compound for Inhibition of SARS Coronavirus Helicase.

    PubMed

    Lee, Jin-Moo; Cho, Jin-Beom; Ahn, Hee-Chul; Jung, Woong; Jeong, Yong-Joo

    2017-11-28

    We have discovered a novel chemical compound, (E)-3-(furan-2-yl)- N -(4-sulfamoylphenyl) acrylamide, that suppresses the enzymatic activities of SARS coronavirus helicase. To determine the inhibitory effect, ATP hydrolysis and double-stranded DNA unwinding assays were performed in the presence of various concentrations of the compound. Through these assays, we obtained IC 50 values of 2.09 ± 0.30 µM (ATP hydrolysis) and 13.2 ± 0.9 µM (DNA unwinding), respectively. Moreover, we found that the compound did not have any significant cytotoxicity when 40 µM of it was used. Our results showed that the compound might be useful to be developed as an inhibitor against SARS coronavirus.

  19. Porcine Reproductive and Respiratory Syndrome Virus Nucleocapsid Protein Interacts with Nsp9 and Cellular DHX9 To Regulate Viral RNA Synthesis.

    PubMed

    Liu, Long; Tian, Jiao; Nan, Hao; Tian, Mengmeng; Li, Yuan; Xu, Xiaodong; Huang, Baicheng; Zhou, Enmin; Hiscox, Julian A; Chen, Hongying

    2016-06-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) nucleocapsid (N) protein is the main component of the viral capsid to encapsulate viral RNA, and it is also a multifunctional protein involved in the regulation of host cell processes. Nonstructural protein 9 (Nsp9) is the RNA-dependent RNA polymerase that plays a critical role in viral RNA transcription and replication. In this study, we demonstrate that PRRSV N protein is bound to Nsp9 by protein-protein interaction and that the contacting surface on Nsp9 is located in the two predicted α-helixes formed by 48 residues at the C-terminal end of the protein. Mutagenesis analyses identified E646, E608, and E611 on Nsp9 and Q85 on the N protein as the pivotal residues participating in the N-Nsp9 interaction. By overexpressing the N protein binding fragment of Nsp9 in infected Marc-145 cells, the synthesis of viral RNAs, as well as the production of infectious progeny viruses, was dramatically inhibited, suggesting that Nsp9-N protein association is involved in the process of viral RNA production. In addition, we show that PRRSV N interacts with cellular RNA helicase DHX9 and redistributes the protein into the cytoplasm. Knockdown of DHX9 increased the ratio of short subgenomic mRNAs (sgmRNAs); in contrast, DHX9 overexpression benefited the synthesis of longer sgmRNAs and the viral genomic RNA (gRNA). These results imply that DHX9 is recruited by the N protein in PRRSV infection to regulate viral RNA synthesis. We postulate that N and DHX9 may act as antiattenuation factors for the continuous elongation of nascent transcript during negative-strand RNA synthesis. It is unclear whether the N protein of PRRSV is involved in regulation of the viral RNA production process. In this report, we demonstrate that the N protein of the arterivirus PRRSV participates in viral RNA replication and transcription through interacting with Nsp9 and its RdRp and recruiting cellular RNA helicase to promote the production of

  20. Glycosylation of the severe acute respiratory syndrome coronavirus triple-spanning membrane proteins 3a and M.

    PubMed

    Oostra, M; de Haan, C A M; de Groot, R J; Rottier, P J M

    2006-03-01

    The severe acute respiratory syndrome coronavirus (SARS-CoV) open reading frame 3a protein has recently been shown to be a structural protein. The protein is encoded by one of the so-called group-specific genes and has no sequence homology with any of the known structural or group-specific proteins of coronaviruses. It does, however, have several similarities to the coronavirus M proteins; (i) they are triple membrane spanning with the same topology, (ii) they have similar intracellular localizations (predominantly Golgi), (iii) both are viral structural proteins, and (iv) they appear to interact with the E and S proteins, as well as with each other. The M protein plays a crucial role in coronavirus assembly and is glycosylated in all coronaviruses, either by N-linked or by O-linked oligosaccharides. The conserved glycosylation of the coronavirus M proteins and the resemblance of the 3a protein to them led us to investigate the glycosylation of these two SARS-CoV membrane proteins. The proteins were expressed separately using the vaccinia virus T7 expression system, followed by metabolic labeling. Pulse-chase analysis showed that both proteins were modified, although in different ways. While the M protein acquired cotranslationally oligosaccharides that could be removed by PNGaseF, the 3a protein acquired its modifications posttranslationally, and they were not sensitive to the N-glycosidase enzyme. The SARS-CoV 3a protein, however, was demonstrated to contain sialic acids, indicating the presence of oligosaccharides. O-glycosylation of the 3a protein was indeed confirmed using an in situ O-glycosylation assay of endoplasmic reticulum-retained mutants. In addition, we showed that substitution of serine and threonine residues in the ectodomain of the 3a protein abolished the addition of the O-linked sugars. Thus, the SARS-CoV 3a protein is an O-glycosylated glycoprotein, like the group 2 coronavirus M proteins but unlike the SARS-CoV M protein, which is N

  1. Loss of Topoisomerase I leads to R-loop-mediated transcriptional blocks during ribosomal RNA synthesis

    PubMed Central

    El Hage, Aziz; French, Sarah L.; Beyer, Ann L.; Tollervey, David

    2010-01-01

    Pre-rRNA transcription by RNA Polymerase I (Pol I) is very robust on active rDNA repeats. Loss of yeast Topoisomerase I (Top1) generated truncated pre-rRNA fragments, which were stabilized in strains lacking TRAMP (Trf4/Trf5–Air1/Air2–Mtr4 polyadenylation complexes) or exosome degradation activities. Loss of both Top1 and Top2 blocked pre-rRNA synthesis, with pre-rRNAs truncated predominately in the 18S 5′ region. Positive supercoils in front of Pol I are predicted to slow elongation, while rDNA opening in its wake might cause R-loop formation. Chromatin immunoprecipitation analysis showed substantial levels of RNA/DNA hybrids in the wild type, particularly over the 18S 5′ region. The absence of RNase H1 and H2 in cells depleted of Top1 increased the accumulation of RNA/DNA hybrids and reduced pre-rRNA truncation and pre-rRNA synthesis. Hybrid accumulation over the rDNA was greatly exacerbated when Top1, Top2, and RNase H were all absent. Electron microscopy (EM) analysis revealed Pol I pileups in the wild type, particularly over the 18S. Pileups were longer and more frequent in the absence of Top1, and their frequency was exacerbated when RNase H activity was also lacking. We conclude that the loss of Top1 enhances inherent R-loop formation, particularly over the 5′ region of the rDNA, imposing persistent transcription blocks when RNase H is limiting. PMID:20634320

  2. Discovery of a novel bottlenose dolphin coronavirus reveals a distinct species of marine mammal coronavirus in Gammacoronavirus.

    PubMed

    Woo, Patrick C Y; Lau, Susanna K P; Lam, Carol S F; Tsang, Alan K L; Hui, Suk-Wai; Fan, Rachel Y Y; Martelli, Paolo; Yuen, Kwok-Yung

    2014-01-01

    While gammacoronaviruses mainly comprise infectious bronchitis virus (IBV) and its closely related bird coronaviruses (CoVs), the only mammalian gammacoronavirus was discovered from a white beluga whale (beluga whale CoV [BWCoV] SW1) in 2008. In this study, we discovered a novel gammacoronavirus from fecal samples from three Indo-Pacific bottlenose dolphins (Tursiops aduncus), which we named bottlenose dolphin CoV (BdCoV) HKU22. All the three BdCoV HKU22-positive samples were collected on the same date, suggesting a cluster of infection, with viral loads of 1 × 10(3) to 1 × 10(5) copies per ml. Clearance of virus was associated with a specific antibody response against the nucleocapsid of BdCoV HKU22. Complete genome sequencing and comparative genome analysis showed that BdCoV HKU22 and BWCoV SW1 have similar genome characteristics and structures. Their genome size is about 32,000 nucleotides, the largest among all CoVs, as a result of multiple unique open reading frames (NS5a, NS5b, NS5c, NS6, NS7, NS8, NS9, and NS10) between their membrane (M) and nucleocapsid (N) protein genes. Although comparative genome analysis showed that BdCoV HKU22 and BWCoV SW1 should belong to the same species, a major difference was observed in the proteins encoded by their spike (S) genes, which showed only 74.3 to 74.7% amino acid identities. The high ratios of the number of synonymous substitutions per synonymous site (Ks) to the number of nonsynonymous substitutions per nonsynonymous site (Ka) in multiple regions of the genome, especially the S gene (Ka/Ks ratio, 2.5), indicated that BdCoV HKU22 may be evolving rapidly, supporting a recent transmission event to the bottlenose dolphins. We propose a distinct species, Cetacean coronavirus, in Gammacoronavirus, to include BdCoV HKU22 and BWCoV SW1, whereas IBV and its closely related bird CoVs represent another species, Avian coronavirus, in Gammacoronavirus.

  3. The SARS-Coronavirus-Host Interactome: Identification of Cyclophilins as Target for Pan-Coronavirus Inhibitors

    PubMed Central

    Friedel, Caroline C.; Müller, Marcel A.; Carbajo-Lozoya, Javier; Stellberger, Thorsten; von Dall’Armi, Ekatarina; Herzog, Petra; Kallies, Stefan; Niemeyer, Daniela; Ditt, Vanessa; Kuri, Thomas; Züst, Roland; Pumpor, Ksenia; Hilgenfeld, Rolf; Schwarz, Frank; Zimmer, Ralf; Steffen, Imke; Weber, Friedemann; Thiel, Volker; Herrler, Georg; Thiel, Heinz-Jürgen; Schwegmann-Weßels, Christel; Pöhlmann, Stefan; Haas, Jürgen; Drosten, Christian; von Brunn, Albrecht

    2011-01-01

    Coronaviruses (CoVs) are important human and animal pathogens that induce fatal respiratory, gastrointestinal and neurological disease. The outbreak of the severe acute respiratory syndrome (SARS) in 2002/2003 has demonstrated human vulnerability to (Coronavirus) CoV epidemics. Neither vaccines nor therapeutics are available against human and animal CoVs. Knowledge of host cell proteins that take part in pivotal virus-host interactions could define broad-spectrum antiviral targets. In this study, we used a systems biology approach employing a genome-wide yeast-two hybrid interaction screen to identify immunopilins (PPIA, PPIB, PPIH, PPIG, FKBP1A, FKBP1B) as interaction partners of the CoV non-structural protein 1 (Nsp1). These molecules modulate the Calcineurin/NFAT pathway that plays an important role in immune cell activation. Overexpression of NSP1 and infection with live SARS-CoV strongly increased signalling through the Calcineurin/NFAT pathway and enhanced the induction of interleukin 2, compatible with late-stage immunopathogenicity and long-term cytokine dysregulation as observed in severe SARS cases. Conversely, inhibition of cyclophilins by cyclosporine A (CspA) blocked the replication of CoVs of all genera, including SARS-CoV, human CoV-229E and -NL-63, feline CoV, as well as avian infectious bronchitis virus. Non-immunosuppressive derivatives of CspA might serve as broad-range CoV inhibitors applicable against emerging CoVs as well as ubiquitous pathogens of humans and livestock. PMID:22046132

  4. Nucleolar TRF2 attenuated nucleolus stress-induced HCC cell-cycle arrest by altering rRNA synthesis.

    PubMed

    Yuan, Fuwen; Xu, Chenzhong; Li, Guodong; Tong, Tanjun

    2018-05-03

    The nucleolus is an important organelle that is responsible for the biogenesis of ribosome RNA (rRNA) and ribosomal subunits assembly. It is also deemed to be the center of metabolic control, considering the critical role of ribosomes in protein translation. Perturbations of rRNA synthesis are closely related to cell proliferation and tumor progression. Telomeric repeat-binding factor 2 (TRF2) is a member of shelterin complex that is responsible for telomere DNA protection. Interestingly, it was recently reported to localize in the nucleolus of human cells in a cell-cycle-dependent manner, while the underlying mechanism and its role on the nucleolus remained unclear. In this study, we found that nucleolar and coiled-body phosphoprotein 1 (NOLC1), a nucleolar protein that is responsible for the nucleolus construction and rRNA synthesis, interacted with TRF2 and mediated the shuttle of TRF2 between the nucleolus and nucleus. Abating the expression of NOLC1 decreased the nucleolar-resident TRF2. Besides, the nucleolar TRF2 could bind rDNA and promoted rRNA transcription. Furthermore, in hepatocellular carcinoma (HCC) cell lines HepG2 and SMMC7721, TRF2 overexpression participated in the nucleolus stress-induced rRNA inhibition and cell-cycle arrest.

  5. Replication of tobacco mosaic virus RNA.

    PubMed Central

    Buck, K W

    1999-01-01

    The replication of tobacco mosaic virus (TMV) RNA involves synthesis of a negative-strand RNA using the genomic positive-strand RNA as a template, followed by the synthesis of positive-strand RNA on the negative-strand RNA templates. Intermediates of replication isolated from infected cells include completely double-stranded RNA (replicative form) and partly double-stranded and partly single-stranded RNA (replicative intermediate), but it is not known whether these structures are double-stranded or largely single-stranded in vivo. The synthesis of negative strands ceases before that of positive strands, and positive and negative strands may be synthesized by two different polymerases. The genomic-length negative strand also serves as a template for the synthesis of subgenomic mRNAs for the virus movement and coat proteins. Both the virus-encoded 126-kDa protein, which has amino-acid sequence motifs typical of methyltransferases and helicases, and the 183-kDa protein, which has additional motifs characteristic of RNA-dependent RNA polymerases, are required for efficient TMV RNA replication. Purified TMV RNA polymerase also contains a host protein serologically related to the RNA-binding subunit of the yeast translational initiation factor, eIF3. Study of Arabidopsis mutants defective in RNA replication indicates that at least two host proteins are needed for TMV RNA replication. The tomato resistance gene Tm-1 may also encode a mutant form of a host protein component of the TMV replicase. TMV replicase complexes are located on the endoplasmic reticulum in close association with the cytoskeleton in cytoplasmic bodies called viroplasms, which mature to produce 'X bodies'. Viroplasms are sites of both RNA replication and protein synthesis, and may provide compartments in which the various stages of the virus mutiplication cycle (protein synthesis, RNA replication, virus movement, encapsidation) are localized and coordinated. Membranes may also be important for the

  6. The Ebola Virus VP30-NP Interaction Is a Regulator of Viral RNA Synthesis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kirchdoerfer, Robert N.; Moyer, Crystal L.; Abelson, Dafna M.

    Filoviruses are capable of causing deadly hemorrhagic fevers. All nonsegmented negative-sense RNA-virus nucleocapsids are composed of a nucleoprotein (NP), a phosphoprotein (VP35) and a polymerase (L). However, the VP30 RNA-synthesis co-factor is unique to the filoviruses. The assembly, structure, and function of the filovirus RNA replication complex remain unclear. Here, we have characterized the interactions of Ebola, Sudan and Marburg virus VP30 with NP using in vitro biochemistry, structural biology and cell-based mini-replicon assays. We have found that the VP30 C-terminal domain interacts with a short peptide in the C-terminal region of NP. Further, we have solved crystal structures ofmore » the VP30-NP complex for both Ebola and Marburg viruses. These structures reveal that a conserved, proline-rich NP peptide binds a shallow hydrophobic cleft on the VP30 C-terminal domain. Structure-guided Ebola virus VP30 mutants have altered affinities for the NP peptide. Correlation of these VP30-NP affinities with the activity for each of these mutants in a cell-based mini-replicon assay suggests that the VP30-NP interaction plays both essential and inhibitory roles in Ebola virus RNA synthesis.« less

  7. Synthesis, base pairing and structure studies of geranylated RNA

    PubMed Central

    Wang, Rui; Vangaveti, Sweta; Ranganathan, Srivathsan V.; Basanta-Sanchez, Maria; Haruehanroengra, Phensinee; Chen, Alan; Sheng, Jia

    2016-01-01

    Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. 2-Thiouridine geranylation is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, such as Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella Typhimurium. The geranylated residues are located in the first anticodon position of tRNAs specific for lysine, glutamine and glutamic acid. This big hydrophobic terpene functional group affects the codon recognition patterns and reduces frameshifting errors during translation. We aimed to systematically study the structure, function and biosynthesis mechanism of this geranylation pathway, as well as answer the question of why nature uses such a hydrophobic modification in hydrophilic RNA systems. Recently, we have synthesized the deoxy-analog of S-geranyluridine and showed the geranylated T-G pair is much stronger than the geranylated T-A pair and other mismatched pairs in the B-form DNA duplex context, which is consistent with the observation that the geranylated tRNAGluUUC recognizes GAG more efficiently than GAA. In this manuscript we report the synthesis and base pairing specificity studies of geranylated RNA oligos. We also report extensive molecular simulation studies to explore the structural features of the geranyl group in the context of A-form RNA and its effect on codon–anticodon interaction during ribosome binding. PMID:27307604

  8. SARS-associated Coronavirus Transmitted from Human to Pig

    PubMed Central

    Chen, Weijun; Yan, Minghua; Yang, Ling; Ding, Boliang; He, Bo; Wang, Yingzhen; Liu, Xiuli; Liu, Chenhui; Zhu, Hui; You, Bo; Huang, Shengyong; Zhang, Jiangguo; Mu, Feng; Xiang, Zhao; Feng, Xiaoli; Wen, Jie; Fang, Jianqiu; Yu, Jun; Yang, Huanming

    2005-01-01

    Severe acute respiratory syndrome–associated coronavirus (SARS-CoV) was isolated from a pig during a survey for possible routes of viral transmission after a SARS epidemic. Sequence and epidemiology analyses suggested that the pig was infected by a SARS-CoV of human origin. PMID:15757562

  9. A growth-dependent transcription initiation factor (TIF-IA) interacting with RNA polymerase I regulates mouse ribosomal RNA synthesis.

    PubMed

    Schnapp, A; Pfleiderer, C; Rosenbauer, H; Grummt, I

    1990-09-01

    Control of mouse ribosomal RNA synthesis in response to extracellular signals is mediated by TIF-IA, a regulatory factor whose amount or activity correlates with cell proliferation. Factor TIF-IA interacts with RNA polymerase I (pol I), thus converting it into a transcriptionally active holoenzyme, which is able to initiate specifically at the rDNA promoter in the presence of the other auxiliary transcription initiation factors, designated TIF-IB, TIF-IC and UBF. With regard to several criteria, the growth-dependent factor TIF-IA behaves like a bacterial sigma factor: (i) it associates physically with pol I, (ii) it is required for initiation of transcription, (iii) it is present in limiting amounts and (iv) under certain salt conditions, it is chromatographically separable from the polymerase. In addition, evidence is presented that dephosphorylation of pol I abolishes in vitro transcription initiation from the ribosomal gene promoter without significantly affecting the polymerizing activity of the enzyme at nonspecific templates. The involvement of both a regulatory factor and post-translational modification of the transcribing enzyme provides an efficient and versatile mechanism of rDNA transcription regulation which enables the cell to adapt ribosome synthesis rapidly to a variety of extracellular signals.

  10. Comparative Evaluation of Three Homogenization Methods for Isolating Middle East Respiratory Syndrome Coronavirus Nucleic Acids From Sputum Samples for Real-Time Reverse Transcription PCR.

    PubMed

    Sung, Heungsup; Yong, Dongeun; Ki, Chang Seok; Kim, Jae Seok; Seong, Moon Woo; Lee, Hyukmin; Kim, Mi Na

    2016-09-01

    Real-time reverse transcription PCR (rRT-PCR) of sputum samples is commonly used to diagnose Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Owing to the difficulty of extracting RNA from sputum containing mucus, sputum homogenization is desirable prior to nucleic acid isolation. We determined optimal homogenization methods for isolating viral nucleic acids from sputum. We evaluated the following three sputum-homogenization methods: proteinase K and DNase I (PK-DNase) treatment, phosphate-buffered saline (PBS) treatment, and N-acetyl-L-cysteine and sodium citrate (NALC) treatment. Sputum samples were spiked with inactivated MERS-CoV culture isolates. RNA was extracted from pretreated, spiked samples using the easyMAG system (bioMérieux, France). Extracted RNAs were then subjected to rRT-PCR for MERS-CoV diagnosis (DiaPlex Q MERS-coronavirus, SolGent, Korea). While analyzing 15 spiked sputum samples prepared in technical duplicate, false-negative results were obtained with five (16.7%) and four samples (13.3%), respectively, by using the PBS and NALC methods. The range of threshold cycle (Ct) values observed when detecting upE in sputum samples was 31.1-35.4 with the PK-DNase method, 34.7-39.0 with the PBS method, and 33.9-38.6 with the NALC method. Compared with the control, which were prepared by adding a one-tenth volume of 1:1,000 diluted viral culture to PBS solution, the ranges of Ct values obtained by the PBS and NALC methods differed significantly from the mean control Ct of 33.2 (both P<0.0001). The PK-DNase method is suitable for homogenizing sputum samples prior to RNA extraction.

  11. Feline coronavirus replication is affected by both cyclophilin A and cyclophilin B.

    PubMed

    Tanaka, Yoshikazu; Sato, Yuka; Sasaki, Takashi

    2017-02-01

    Feline coronavirus (FCoV) causes the fatal disease feline infectious peritonitis, which is currently incurable by drug treatment, and no effective vaccines are available. Cyclosporin A (CsA), a cyclophilin (Cyp) inhibitor, inhibits the replication of FCoV in vitro and in vivo as well as the replication of human and animal coronaviruses. However, the mechanism underlying the regulation of coronavirus replication by CsA is unknown. In this study, we analysed the role of Cyps in FCoV replication using knockdown and knockout cells specific to Cyps. Inhibition of CypA and CypB reduced FCoV replication, with replication in knockout cells being much less than that in knockdown cells. Furthermore, the proteins expressed by CypA and CypB harbouring mutations in their respective predicted peptidyl-prolyl cis-transisomerase active sites, which also alter the affinities between Cyps and CsA, inhibited FCoV replication. These findings indicate that the peptidyl-prolyl cis-transisomerase active sites of Cyps might be required for FCoV replication.

  12. A non-catalytic role for inositol 1,3,4,5,6-pentakisphosphate 2-kinase in the synthesis of ribosomal RNA

    PubMed Central

    Brehm, Maria A.; Wundenberg, Torsten; Williams, Jason; Mayr, Georg W.; Shears, Stephen B.

    2013-01-01

    Summary Fundamental to the life and destiny of every cell is the regulation of protein synthesis through ribosome biogenesis, which begins in the nucleolus with the production of ribosomal RNA (rRNA). Nucleolar organization is a highly dynamic and tightly regulated process; the structural factors that direct nucleolar assembly and disassembly are just as important in controlling rRNA synthesis as are the catalytic activities that synthesize rRNA. Here, we report that a signaling enzyme, inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5K) is also a structural component in the nucleolus. We demonstrate that IP5K has functionally significant interactions with three proteins that regulate rRNA synthesis: protein kinase CK2, TCOF1 and upstream-binding-factor (UBF). Through molecular modeling and mutagenic studies, we identified an Arg-Lys-Lys tripeptide located on the surface of IP5K that mediates its association with UBF. Nucleolar IP5K spatial dynamics were sensitive to experimental procedures (serum starvation or addition of actinomycin D) that inhibited rRNA production. We show that IP5K makes stoichiometrically sensitive contributions to the architecture of the nucleoli in intact cells, thereby influencing the degree of rRNA synthesis. Our study adds significantly to the biological significance of IP5K; previously, it was the kinase activity of this protein that had attracted attention. Our demonstration that IP5K ‘moonlights’ as a molecular scaffold offers an unexpected new example of how the biological sophistication of higher organisms can arise from gene products acquiring multiple functions, rather than by an increase in gene number. PMID:23203802

  13. A non-catalytic role for inositol 1,3,4,5,6-pentakisphosphate 2-kinase in the synthesis of ribosomal RNA.

    PubMed

    Brehm, Maria A; Wundenberg, Torsten; Williams, Jason; Mayr, Georg W; Shears, Stephen B

    2013-01-15

    Fundamental to the life and destiny of every cell is the regulation of protein synthesis through ribosome biogenesis, which begins in the nucleolus with the production of ribosomal RNA (rRNA). Nucleolar organization is a highly dynamic and tightly regulated process; the structural factors that direct nucleolar assembly and disassembly are just as important in controlling rRNA synthesis as are the catalytic activities that synthesize rRNA. Here, we report that a signaling enzyme, inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5K) is also a structural component in the nucleolus. We demonstrate that IP5K has functionally significant interactions with three proteins that regulate rRNA synthesis: protein kinase CK2, TCOF1 and upstream-binding-factor (UBF). Through molecular modeling and mutagenic studies, we identified an Arg-Lys-Lys tripeptide located on the surface of IP5K that mediates its association with UBF. Nucleolar IP5K spatial dynamics were sensitive to experimental procedures (serum starvation or addition of actinomycin D) that inhibited rRNA production. We show that IP5K makes stoichiometrically sensitive contributions to the architecture of the nucleoli in intact cells, thereby influencing the degree of rRNA synthesis. Our study adds significantly to the biological significance of IP5K; previously, it was the kinase activity of this protein that had attracted attention. Our demonstration that IP5K 'moonlights' as a molecular scaffold offers an unexpected new example of how the biological sophistication of higher organisms can arise from gene products acquiring multiple functions, rather than by an increase in gene number.

  14. RNA Crystallization

    NASA Technical Reports Server (NTRS)

    Golden, Barbara L.; Kundrot, Craig E.

    2003-01-01

    RNA molecules may be crystallized using variations of the methods developed for protein crystallography. As the technology has become available to syntheisize and purify RNA molecules in the quantities and with the quality that is required for crystallography, the field of RNA structure has exploded. The first consideration when crystallizing an RNA is the sequence, which may be varied in a rational way to enhance crystallizability or prevent formation of alternate structures. Once a sequence has been designed, the RNA may be synthesized chemically by solid-state synthesis, or it may be produced enzymatically using RNA polymerase and an appropriate DNA template. Purification of milligram quantities of RNA can be accomplished by HPLC or gel electrophoresis. As with proteins, crystallization of RNA is usually accomplished by vapor diffusion techniques. There are several considerations that are either unique to RNA crystallization or more important for RNA crystallization. Techniques for design, synthesis, purification, and crystallization of RNAs will be reviewed here.

  15. Isolation and characterization of a bat SARS-like coronavirus that uses the ACE2 receptor.

    PubMed

    Ge, Xing-Yi; Li, Jia-Lu; Yang, Xing-Lou; Chmura, Aleksei A; Zhu, Guangjian; Epstein, Jonathan H; Mazet, Jonna K; Hu, Ben; Zhang, Wei; Peng, Cheng; Zhang, Yu-Ji; Luo, Chu-Ming; Tan, Bing; Wang, Ning; Zhu, Yan; Crameri, Gary; Zhang, Shu-Yi; Wang, Lin-Fa; Daszak, Peter; Shi, Zheng-Li

    2013-11-28

    The 2002-3 pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV) was one of the most significant public health events in recent history. An ongoing outbreak of Middle East respiratory syndrome coronavirus suggests that this group of viruses remains a key threat and that their distribution is wider than previously recognized. Although bats have been suggested to be the natural reservoirs of both viruses, attempts to isolate the progenitor virus of SARS-CoV from bats have been unsuccessful. Diverse SARS-like coronaviruses (SL-CoVs) have now been reported from bats in China, Europe and Africa, but none is considered a direct progenitor of SARS-CoV because of their phylogenetic disparity from this virus and the inability of their spike proteins to use the SARS-CoV cellular receptor molecule, the human angiotensin converting enzyme II (ACE2). Here we report whole-genome sequences of two novel bat coronaviruses from Chinese horseshoe bats (family: Rhinolophidae) in Yunnan, China: RsSHC014 and Rs3367. These viruses are far more closely related to SARS-CoV than any previously identified bat coronaviruses, particularly in the receptor binding domain of the spike protein. Most importantly, we report the first recorded isolation of a live SL-CoV (bat SL-CoV-WIV1) from bat faecal samples in Vero E6 cells, which has typical coronavirus morphology, 99.9% sequence identity to Rs3367 and uses ACE2 from humans, civets and Chinese horseshoe bats for cell entry. Preliminary in vitro testing indicates that WIV1 also has a broad species tropism. Our results provide the strongest evidence to date that Chinese horseshoe bats are natural reservoirs of SARS-CoV, and that intermediate hosts may not be necessary for direct human infection by some bat SL-CoVs. They also highlight the importance of pathogen-discovery programs targeting high-risk wildlife groups in emerging disease hotspots as a strategy for pandemic preparedness.

  16. Myeloablation-associated deletion of ORF4 in a human coronavirus 229E infection.

    PubMed

    Greninger, Alexander L; Pepper, Gregory; Shean, Ryan C; Cent, Anne; Palileo, Isabel; Kuypers, Jane M; Schiffer, Joshua T; Jerome, Keith R

    2017-01-01

    We describe metagenomic next-generation sequencing (mNGS) of a human coronavirus 229E from a patient with AML and persistent upper respiratory symptoms, who underwent hematopoietic cell transplantation (HCT). mNGS revealed a 548-nucleotide deletion, which comprised the near entirety of the ORF4 gene, and no minor allele variants were detected to suggest a mixed infection. As part of her pre-HCT conditioning regimen, the patient received myeloablative treatment with cyclophosphamide and 12 Gy total body irradiation. Iterative sequencing and RT-PCR confirmation of four respiratory samples over the 4-week peritransplant period revealed that the pre-conditioning strain contained an intact ORF4 gene, while the deletion strain appeared just after conditioning and persisted over a 2.5-week period. This sequence represents one of the largest genomic deletions detected in a human RNA virus and describes large-scale viral mutation associated with myeloablation for HCT.

  17. Rice yellow stunt rhabdovirus protein 6 suppresses systemic RNA silencing by blocking RDR6-mediated secondary siRNA synthesis.

    PubMed

    Guo, Hongyan; Song, Xiaoguang; Xie, Chuanmiao; Huo, Yan; Zhang, Fujie; Chen, Xiaoying; Geng, Yunfeng; Fang, Rongxiang

    2013-08-01

    The P6 protein of Rice yellow stunt rhabdovirus (RYSV) is a virion structural protein that can be phosphorylated in vitro. However its exact function remains elusive. We found that P6 enhanced the virulence of Potato virus X (PVX) in Nicotiana benthamiana and N. tabacum plants, suggesting that it might function as a suppressor of RNA silencing. We examined the mechanism of P6-mediated silencing suppression by transiently expressing P6 in both N. benthamiana leaves and rice protoplasts. Our results showed that P6 could repress the production of secondary siRNAs and inhibit systemic green fluorescent protein RNA silencing but did not interfere with local RNA silencing in N. benthamiana plants or in rice protoplasts. Intriguingly, P6 and RDR6 had overlapping subcellular localization and P6 bound both rice and Arabidopsis RDR6 in vivo. Furthermore, transgenic rice plants expressing P6 showed enhanced susceptibility to infection by Rice stripe virus. Hence, we propose that P6 is part of the RYSV's counter-defense machinery against the plant RNA silencing system and plays a role mainly in affecting RDR6-mediated secondary siRNA synthesis. Our work provides a new perspective on how a plant-infecting nucleorhabdovirus may counteract host RNA silencing-mediated antiviral defense.

  18. Genetic Assay for Transcription Errors: Methods to Monitor Treatments or Chemicals that Increase the Error Rate of RNA synthesis | NCI Technology Transfer Center | TTC

    Cancer.gov

    Researchers at the National Cancer Institute (NCI) developed a genetic assay for detecting transcription errors in RNA synthesis. This new assay extends the familiar concept of an Ames test which monitors DNA damage and synthesis errors to the previously inaccessible issue of RNA synthesis fidelity. The FDA requires genetic DNA focused tests for all drug approval as it assesses the in vivo mutagenic and carcinogenic potential of a drug. The new assay will open an approach to monitoring the impact of treatments on the accuracy of RNA synthesis. Errors in transcription have been hypothesized to be a component of aging and age-related diseases. The National Cancer Institute (NCI) seeks licensing partners for the genetic assay.

  19. Initiation of poliovirus plus-strand RNA synthesis in a membrane complex of infected HeLa cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Takeda, N.; Kuhn, R.J.; Yang, C.F.

    1986-10-01

    An in vitro poliovirus RNA-synthesizing system derived from a crude membrance fraction of infected HeLa cells was used to analyze the mechanism of initiation of poliovirus plus-strand RNA synthesis. This system contains an activity that synthesizes the nucleotidyl proteins VPg-pU and VPg-pUpU. These molecules represent the 5'-terminal structure of nascent RNA molecules and of virion RNA. The membranous replication complex is also capable of synthesizing mucleotidyl proteins containing nine or more of the poliovirus 5'-proximal nucleotides as assayed by the formation of the RNase T/sub 1/-resistant oligonucleotide VPg-pUUAAAACAGp or by fingerprint analysis of the in vitro-synthesized /sup 32/P-RNA. Incubation ofmore » preformed VPg-pUpU with unlabeled nucleoside triphosphates resulted in the formation of VPg-pUUAAAACAGp. This reaction, which appeared to be an elongation of VPg-pUpU, was stimulated by the addition of a soluble fraction (S-10) obtained from uninfected HeLa cells. Preformed VPg-pU could be chased into VPg-pUpU in the presence of UTP. The data are consistent with a model that VPg-pU can function as a primer for poliovirus plus-strand RNA synthesis in the membranous replication complex and that the elongation reaction may be stimulated by a host cellular factor.« less

  20. Discovery of a novel canine respiratory coronavirus support genetic recombination among betacoronavirus1.

    PubMed

    Lu, Shuai; Wang, Yanqun; Chen, Yingzhu; Wu, Bingjie; Qin, Kun; Zhao, Jincun; Lou, Yongliang; Tan, Wenjie

    2017-06-02

    Although canine respiratory coronavirus (CRCoV) is an important respiratory pathogen that is prevalent in many countries, only one complete genome sequence of CRCoV (South Korea strain K37) has been obtained to date. Genome-wide analyses and recombination have rarely been conducted, as small numbers of samples and limited genomic characterization have previously prevented further analyses. Herein, we report a unique CRCoV strain, denoted strain BJ232, derived from a CRCoV-positive dog with a mild respiratory infection. Phylogenetic analysis based on complete genome of all available coronaviruses consistently show that CRCoV BJ232 is most closely related to human coronavirus OC43 (HCoV-OC43) and BCoV, forming a separate clade that split off early from other Betacoronavirus 1. Based on the phylogenetic and SimPlot analysis we propose that CRCoV-K37 was derived from genetic recombination between CRCoV-BJ232 and BCoV. In detail, spike (S) gene of CRCoV-K37 clustered with CRCoV-BJ232. However orf1ab, membrane (M) and nucleocapsid (N) genes were more related to Bovine coronavirus (BCoV) than CRCoV-B232. Molecular epidemic analysis confirmed the prevalence of CRCoV-BJ232 lineage around the world for a long time. Recombinant events among Betacoronavirus 1 may have implications for CRCoV transmissibility. All these findings provide further information regarding the origin of CRCoV. Copyright © 2017. Published by Elsevier B.V.

  1. DNA and RNA Synthesis in Animal Cells in Culture--Methods for Use in Schools

    ERIC Educational Resources Information Center

    Godsell, P. M.; Balls, M.

    1973-01-01

    Describes the experimental procedures used for detecting DNA and RNA synthesis in xenopus cells by autoradiography. The method described is suitable for senior high school laboratory classes or biology projects, if supervised by a teacher qualified to handle radioisotopes. (JR)

  2. MicroRNA and Transcriptomic Profiling Showed miRNA-Dependent Impairment of Systemic Regulation and Synthesis of Biomolecules in Rag2 KO Mice.

    PubMed

    Reza, Abu Musa Md Talimur; Choi, Yun-Jung; Kim, Jin-Hoi

    2018-02-27

    The Rag2 knockout (KO) mouse is a well-established immune-compromised animal model for biomedical research. A comparative study identified the deregulated expression of microRNAs (miRNAs) and messenger RNAs (mRNAs) in Rag2 KO mice. However, the interaction between deregulated genes and miRNAs in the alteration of systemic (cardiac, renal, hepatic, nervous, and hematopoietic) regulations and the synthesis of biomolecules (such as l-tryptophan, serotonin, melatonin, dopamine, alcohol, noradrenaline, putrescine, and acetate) are unclear. In this study, we analyzed both miRNA and mRNA expression microarray data from Rag2 KO and wild type mice to investigate the possible role of miRNAs in systemic regulation and biomolecule synthesis. A notable finding obtained from this analysis is that the upregulation of several genes which are target molecules of the downregulated miRNAs in Rag2 KO mice, can potentially trigger the degradation of l-tryptophan, thereby leading to the systemic impairment and alteration of biomolecules synthesis as well as changes in behavioral patterns (such as stress and fear responses, and social recognition memory) in Rag2 gene-depleted mice. These findings were either not observed or not explicitly described in other published Rag2 KO transcriptome analyses. In conclusion, we have provided an indication of miRNA-dependent regulations of clinical and pathological conditions in cardiac, renal, hepatic, nervous, and hematopoietic systems in Rag2 KO mice. These results may significantly contribute to the prediction of clinical disease caused by Rag2 deficiency.

  3. Bat-to-human: spike features determining 'host jump' of coronaviruses SARS-CoV, MERS-CoV, and beyond.

    PubMed

    Lu, Guangwen; Wang, Qihui; Gao, George F

    2015-08-01

    Both severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) are zoonotic pathogens that crossed the species barriers to infect humans. The mechanism of viral interspecies transmission is an important scientific question to be addressed. These coronaviruses contain a surface-located spike (S) protein that initiates infection by mediating receptor-recognition and membrane fusion and is therefore a key factor in host specificity. In addition, the S protein needs to be cleaved by host proteases before executing fusion, making these proteases a second determinant of coronavirus interspecies infection. Here, we summarize the progress made in the past decade in understanding the cross-species transmission of SARS-CoV and MERS-CoV by focusing on the features of the S protein, its receptor-binding characteristics, and the cleavage process involved in priming. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. An In Vitro RNA Synthesis Assay for Rabies Virus Defines Ribonucleoprotein Interactions Critical for Polymerase Activity.

    PubMed

    Morin, Benjamin; Liang, Bo; Gardner, Erica; Ross, Robin A; Whelan, Sean P J

    2017-01-01

    We report an in vitro RNA synthesis assay for the RNA-dependent RNA polymerase (RdRP) of rabies virus (RABV). We expressed RABV large polymerase protein (L) in insect cells from a recombinant baculovirus vector and the phosphoprotein cofactor (P) in Escherichia coli and purified the resulting proteins by affinity and size exclusion chromatography. Using chemically synthesized short RNA corresponding to the first 19 nucleotides (nt) of the rabies virus genome, we demonstrate that L alone initiates synthesis on naked RNA and that P serves to enhance the initiation and processivity of the RdRP. The L-P complex lacks full processivity, which we interpret to reflect the lack of the viral nucleocapsid protein (N) on the template. Using this assay, we define the requirements in P for stimulation of RdRP activity as residues 11 to 50 of P and formally demonstrate that ribavirin triphosphate (RTP) inhibits the RdRP. By comparing the properties of RABV RdRP with those of the related rhabdovirus, vesicular stomatitis virus (VSV), we demonstrate that both polymerases can copy the heterologous promoter sequence. The requirements for engagement of the N-RNA template of VSV by its polymerase are provided by the C-terminal domain (CTD) of P. A chimeric RABV P protein in which the oligomerization domain (OD) and the CTD were replaced by those of VSV P stimulated RABV RdRP activity on naked RNA but was insufficient to permit initiation on the VSV N-RNA template. This result implies that interactions between L and the template N are also required for initiation of RNA synthesis, extending our knowledge of ribonucleoprotein interactions that are critical for gene expression. The current understanding of the structural and functional significance of the components of the rabies virus replication machinery is incomplete. Although structures are available for the nucleocapsid protein in complex with RNA, and also for portions of P, information on both the structure and function of the L

  5. Role of the Pepino mosaic virus 3'-untranslated region elements in negative-strand RNA synthesis in vitro.

    PubMed

    Osman, Toba A M; Olsthoorn, René C L; Livieratos, Ioannis C

    2014-09-22

    Pepino mosaic virus (PepMV) is a mechanically-transmitted positive-strand RNA potexvirus, with a 6410 nt long single-stranded (ss) RNA genome flanked by a 5'-methylguanosine cap and a 3' poly-A tail. Computer-assisted folding of the 64 nt long PepMV 3'-untranslated region (UTR) resulted in the prediction of three stem-loop structures (hp1, hp2, and hp3 in the 3'-5' direction). The importance of these structures and/or sequences for promotion of negative-strand RNA synthesis and binding to the RNA dependent RNA polymerase (RdRp) was tested in vitro using a specific RdRp assay. Hp1, which is highly variable among different PepMV isolates, appeared dispensable for negative-strand synthesis. Hp2, which is characterized by a large U-rich loop, tolerated base-pair changes in its stem as long as they maintained the stem integrity but was very sensitive to changes in the U-rich loop. Hp3, which harbours the conserved potexvirus ACUUAA hexamer motif, was essential for template activity. Template-RNA polymerase binding competition experiments showed that the ACUUAA sequence represents a high-affinity RdRp binding element. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Bacteriophage phi 6 RNA-dependent RNA polymerase: molecular details of initiating nucleic acid synthesis without primer.

    PubMed

    Laurila, Minni R L; Makeyev, Eugene V; Bamford, Dennis H

    2002-05-10

    Like most RNA polymerases, the polymerase of double-strand RNA bacteriophage phi6 (phi6pol) is capable of primer-independent initiation. Based on the recently solved phi6pol initiation complex structure, a four-amino acid-long loop (amino acids 630-633) has been suggested to stabilize the first two incoming NTPs through stacking interactions with tyrosine, Tyr(630). A similar loop is also present in the hepatitis C virus polymerase, another enzyme capable of de novo initiation. Here, we use a series of phi6pol mutants to address the role of this element. As predicted, mutants at the Tyr(630) position are inefficient in initiation de novo. Unexpectedly, when the loop is disordered by changing Tyr(630)-Lys(631)-Trp(632) to GSG, phi6pol becomes a primer-dependent enzyme, either extending complementary oligonucleotide or, when the template 3' terminus can adopt a hairpin-like conformation, utilizing a "copy-back" initiation mechanism. In contrast to the wild-type phi6pol, the GSG mutant does not require high GTP concentration for its optimal activity. These findings suggest a general model for the initiation of de novo RNA synthesis.

  7. RNA.

    ERIC Educational Resources Information Center

    Darnell, James E., Jr.

    1985-01-01

    Ribonucleic acid (RNA) converts genetic information into protein and usually must be processed to serve its function. RNA types, chemical structure, protein synthesis, translation, manufacture, and processing are discussed. Concludes that the first genes might have been spliced RNA and that humans might be closer than bacteria to primitive…

  8. Control of Fur synthesis by the non-coding RNA RyhB and iron-responsive decoding.

    PubMed

    Vecerek, Branislav; Moll, Isabella; Bläsi, Udo

    2007-02-21

    The Fe2+-dependent Fur protein serves as a negative regulator of iron uptake in bacteria. As only metallo-Fur acts as an autogeneous repressor, Fe2+scarcity would direct fur expression when continued supply is not obviously required. We show that in Escherichia coli post-transcriptional regulatory mechanisms ensure that Fur synthesis remains steady in iron limitation. Our studies revealed that fur translation is coupled to that of an upstream open reading frame (uof), translation of which is downregulated by the non-coding RNA (ncRNA) RyhB. As RyhB transcription is negatively controlled by metallo-Fur, iron depletion creates a negative feedback loop. RyhB-mediated regulation of uof-fur provides the first example for indirect translational regulation by a trans-encoded ncRNA. In addition, we present evidence for an iron-responsive decoding mechanism of the uof-fur entity. It could serve as a backup mechanism of the RyhB circuitry, and represents the first link between iron availability and synthesis of an iron-containing protein.

  9. Synthesis of double-stranded RNA in a virus-enriched fraction from Agaricus bisporus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sriskantha, A.; Wach, P.; Schlagnhaufer, B.

    Partially purified virus preparations from sporophores of Agaricus bisporus affected with LaFrance disease had up to a 15-fold-higher RNA-dependent RNA polymerase activity than did comparable preparations from health sporophores. Enzyme activity was dependent upon the presence of Mg/sup 2 +/ and the four nucleoside triphosphates and was insensitive to actinomycin D, ..cap alpha..-amanitin, and rifampin. The /sup 3/H-labeled enzyme reaction products were double-stranded RNA (dsRNA) as indicated by CF-11 cellulose column chromatography and by their ionic-strength-dependent sensitivity to hydrolysis by RNase A. The principal dsRNA products had estimated molecular weights of 4.3 /times/ 10/sup 6/ and 1.4 /times/ 10/sup 6/.more » Cs/sub 2/SO/sub 4/ equilibrium centrifugation of the virus preparation resolved a single peak of RNA polymerase activity that banded with a 35-nm spherical virus particle containing dsRNAs with molecular weights of 4.3 /times/ 10/sup 6/ and 1.4 /times/ 10/sup 6/. The data suggest that the RNA-dependent RNA polymerase associated with the 35-nm spherical virus is a replicase which catalyzes the synthesis of the genomic dsRNAs.« less

  10. Middle East respiratory syndrome coronavirus neutralising serum antibodies in dromedary camels: a comparative serological study.

    PubMed

    Reusken, Chantal B E M; Haagmans, Bart L; Müller, Marcel A; Gutierrez, Carlos; Godeke, Gert-Jan; Meyer, Benjamin; Muth, Doreen; Raj, V Stalin; Smits-De Vries, Laura; Corman, Victor M; Drexler, Jan-Felix; Smits, Saskia L; El Tahir, Yasmin E; De Sousa, Rita; van Beek, Janko; Nowotny, Norbert; van Maanen, Kees; Hidalgo-Hermoso, Ezequiel; Bosch, Berend-Jan; Rottier, Peter; Osterhaus, Albert; Gortázar-Schmidt, Christian; Drosten, Christian; Koopmans, Marion P G

    2013-10-01

    A new betacoronavirus-Middle East respiratory syndrome coronavirus (MERS-CoV)-has been identified in patients with severe acute respiratory infection. Although related viruses infect bats, molecular clock analyses have been unable to identify direct ancestors of MERS-CoV. Anecdotal exposure histories suggest that patients had been in contact with dromedary camels or goats. We investigated possible animal reservoirs of MERS-CoV by assessing specific serum antibodies in livestock. We took sera from animals in the Middle East (Oman) and from elsewhere (Spain, Netherlands, Chile). Cattle (n=80), sheep (n=40), goats (n=40), dromedary camels (n=155), and various other camelid species (n=34) were tested for specific serum IgG by protein microarray using the receptor-binding S1 subunits of spike proteins of MERS-CoV, severe acute respiratory syndrome coronavirus, and human coronavirus OC43. Results were confirmed by virus neutralisation tests for MERS-CoV and bovine coronavirus. 50 of 50 (100%) sera from Omani camels and 15 of 105 (14%) from Spanish camels had protein-specific antibodies against MERS-CoV spike. Sera from European sheep, goats, cattle, and other camelids had no such antibodies. MERS-CoV neutralising antibody titres varied between 1/320 and 1/2560 for the Omani camel sera and between 1/20 and 1/320 for the Spanish camel sera. There was no evidence for cross-neutralisation by bovine coronavirus antibodies. MERS-CoV or a related virus has infected camel populations. Both titres and seroprevalences in sera from different locations in Oman suggest widespread infection. European Union, European Centre For Disease Prevention and Control, Deutsche Forschungsgemeinschaft. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Conserved antigenic sites between MERS-CoV and Bat-coronavirus are revealed through sequence analysis.

    PubMed

    Sharmin, Refat; Islam, Abul B M M K

    2016-01-01

    MERS-CoV is a newly emerged human coronavirus reported closely related with HKU4 and HKU5 Bat coronaviruses. Bat and MERS corona-viruses are structurally related. Therefore, it is of interest to estimate the degree of conserved antigenic sites among them. It is of importance to elucidate the shared antigenic-sites and extent of conservation between them to understand the evolutionary dynamics of MERS-CoV. Multiple sequence alignment of the spike (S), membrane (M), enveloped (E) and nucleocapsid (N) proteins was employed to identify the sequence conservation among MERS and Bat (HKU4, HKU5) coronaviruses. We used various in silico tools to predict the conserved antigenic sites. We found that MERS-CoV shared 30 % of its S protein antigenic sites with HKU4 and 70 % with HKU5 bat-CoV. Whereas 100 % of its E, M and N protein's antigenic sites are found to be conserved with those in HKU4 and HKU5. This sharing suggests that in case of pathogenicity MERS-CoV is more closely related to HKU5 bat-CoV than HKU4 bat-CoV. The conserved epitopes indicates their evolutionary relationship and ancestry of pathogenicity.

  12. Small molecules targeting viral RNA.

    PubMed

    Hermann, Thomas

    2016-11-01

    Highly conserved noncoding RNA (ncRNA) elements in viral genomes and transcripts offer new opportunities to expand the repertoire of drug targets for the development of antiinfective therapy. Ligands binding to ncRNA architectures are able to affect interactions, structural stability or conformational changes and thereby block processes essential for viral replication. Proof of concept for targeting functional RNA by small molecule inhibitors has been demonstrated for multiple viruses with RNA genomes. Strategies to identify antiviral compounds as inhibitors of ncRNA are increasingly emphasizing consideration of drug-like properties of candidate molecules emerging from screening and ligand design. Recent efforts of antiviral lead discovery for RNA targets have provided drug-like small molecules that inhibit viral replication and include inhibitors of human immunodeficiency virus (HIV), hepatitis C virus (HCV), severe respiratory syndrome coronavirus (SARS CoV), and influenza A virus. While target selectivity remains a challenge for the discovery of useful RNA-binding compounds, a better understanding is emerging of properties that define RNA targets amenable for inhibition by small molecule ligands. Insight from successful approaches of targeting viral ncRNA in HIV, HCV, SARS CoV, and influenza A will provide a basis for the future exploration of RNA targets for therapeutic intervention in other viral pathogens which create urgent, unmet medical needs. Viruses for which targeting ncRNA components in the genome or transcripts may be promising include insect-borne flaviviruses (Dengue, Zika, and West Nile) and filoviruses (Ebola and Marburg). WIREs RNA 2016, 7:726-743. doi: 10.1002/wrna.1373 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

  13. Real-Time Reverse Transcription–Polymerase Chain Reaction Assay for SARS-associated Coronavirus

    PubMed Central

    Emery, Shannon L.; Bowen, Michael D.; Newton, Bruce R.; Winchell, Jonas M.; Meyer, Richard F.; Tong, Suxiang; Cook, Byron T.; Holloway, Brian P.; McCaustland, Karen A.; Rota, Paul A.; Bankamp, Bettina; Lowe, Luis E.; Ksiazek, Tom G.; Bellini, William J.; Anderson, Larry J.

    2004-01-01

    A real-time reverse transcription–polymerase chain reaction (RT-PCR) assay was developed to rapidly detect the severe acute respiratory syndrome–associated coronavirus (SARS-CoV). The assay, based on multiple primer and probe sets located in different regions of the SARS-CoV genome, could discriminate SARS-CoV from other human and animal coronaviruses with a potential detection limit of <10 genomic copies per reaction. The real-time RT-PCR assay was more sensitive than a conventional RT-PCR assay or culture isolation and proved suitable to detect SARS-CoV in clinical specimens. Application of this assay will aid in diagnosing SARS-CoV infection. PMID:15030703

  14. Coronavirus antibody detection in cats by computer-assisted kinetics-based enzyme-linked immunosorbent assay (KELA): field studies.

    PubMed

    Barlough, J E; Jacobson, R H; Sorresso, G P; Lynch, T J; Scott, F W

    1986-07-01

    A total of 2238 feline serum samples submitted to the New York State Diagnostic Laboratory over a 1-year period were tested for the presence of coronavirus antibodies, using the computer-assisted, kinetics-based enzyme-linked immunosorbent assay (KELA). Cats from which sera were obtained were categorized by sex, age, breed, and disease status, and variations in mean antibody titers for different sub-classifications within each category were analyzed by computerized statistical analysis. As expected, higher mean antibody titers were recorded for cats with feline infectious peritonitis, and for cats with a recent history of possible coronavirus exposure. However, an unexpected inverse relationship between coronavirus antibody titer and age was also found. Certain cattery-oriented pure breeds appeared to have higher mean antibody titers, because their sample populations contained a higher percentage of younger cats and cats of unknown age-groups which, over-all, had higher mean titers. Taken together, the data substantiated the efficacy of the computer-assisted KELA for routine detection of serum coronavirus antibodies in cats.

  15. Comparative Evaluation of Three Homogenization Methods for Isolating Middle East Respiratory Syndrome Coronavirus Nucleic Acids From Sputum Samples for Real-Time Reverse Transcription PCR

    PubMed Central

    Yong, Dongeun; Ki, Chang-Seok; Kim, Jae-Seok; Seong, Moon-Woo; Lee, Hyukmin

    2016-01-01

    Background Real-time reverse transcription PCR (rRT-PCR) of sputum samples is commonly used to diagnose Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Owing to the difficulty of extracting RNA from sputum containing mucus, sputum homogenization is desirable prior to nucleic acid isolation. We determined optimal homogenization methods for isolating viral nucleic acids from sputum. Methods We evaluated the following three sputum-homogenization methods: proteinase K and DNase I (PK-DNase) treatment, phosphate-buffered saline (PBS) treatment, and N-acetyl-L-cysteine and sodium citrate (NALC) treatment. Sputum samples were spiked with inactivated MERS-CoV culture isolates. RNA was extracted from pretreated, spiked samples using the easyMAG system (bioMérieux, France). Extracted RNAs were then subjected to rRT-PCR for MERS-CoV diagnosis (DiaPlex Q MERS-coronavirus, SolGent, Korea). Results While analyzing 15 spiked sputum samples prepared in technical duplicate, false-negative results were obtained with five (16.7%) and four samples (13.3%), respectively, by using the PBS and NALC methods. The range of threshold cycle (Ct) values observed when detecting upE in sputum samples was 31.1–35.4 with the PK-DNase method, 34.7–39.0 with the PBS method, and 33.9–38.6 with the NALC method. Compared with the control, which were prepared by adding a one-tenth volume of 1:1,000 diluted viral culture to PBS solution, the ranges of Ct values obtained by the PBS and NALC methods differed significantly from the mean control Ct of 33.2 (both P<0.0001). Conclusions The PK-DNase method is suitable for homogenizing sputum samples prior to RNA extraction. PMID:27374711

  16. Global patterns in coronavirus diversity

    PubMed Central

    Johnson, Christine K.; Greig, Denise J.; Kramer, Sarah; Che, Xiaoyu; Wells, Heather; Hicks, Allison L.; Joly, Damien O.; Wolfe, Nathan D.; Daszak, Peter; Karesh, William; Lipkin, W. I.; Morse, Stephen S.; Mazet, Jonna A. K.

    2017-01-01

    Abstract Since the emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrom Coronavirus (MERS-CoV) it has become increasingly clear that bats are important reservoirs of CoVs. Despite this, only 6% of all CoV sequences in GenBank are from bats. The remaining 94% largely consist of known pathogens of public health or agricultural significance, indicating that current research effort is heavily biased towards describing known diseases rather than the ‘pre-emergent’ diversity in bats. Our study addresses this critical gap, and focuses on resource poor countries where the risk of zoonotic emergence is believed to be highest. We surveyed the diversity of CoVs in multiple host taxa from twenty countries to explore the factors driving viral diversity at a global scale. We identified sequences representing 100 discrete phylogenetic clusters, ninety-one of which were found in bats, and used ecological and epidemiologic analyses to show that patterns of CoV diversity correlate with those of bat diversity. This cements bats as the major evolutionary reservoirs and ecological drivers of CoV diversity. Co-phylogenetic reconciliation analysis was also used to show that host switching has contributed to CoV evolution, and a preliminary analysis suggests that regional variation exists in the dynamics of this process. Overall our study represents a model for exploring global viral diversity and advances our fundamental understanding of CoV biodiversity and the potential risk factors associated with zoonotic emergence. PMID:28630747

  17. Cerebral pyogranuloma associated with systemic coronavirus infection in a ferret.

    PubMed

    Gnirs, K; Quinton, J F; Dally, C; Nicolier, A; Ruel, Y

    2016-01-01

    A 2-year-old male ferret was presented with central nervous system signs. Computed tomography (CT) of the brain revealed a well-defined contrast-enhancing lesion on the rostral forebrain that appeared extraparenchymal. Surgical excision of the mass was performed and the ferret was euthanised during the procedure. Histopathology of the excised mass showed multiple meningeal nodular lesions with infiltrates of epithelioid macrophages, occasionally centred on degenerated neutrophils and surrounded by a broad rim of plasma cells, features consistent with pyogranulomatous meningitis. The histopathological features in this ferret were similar to those in cats with feline infectious peritonitis. Definitive diagnosis was assessed by immunohistochemistry, confirming a ferret systemic coronavirus (FSCV) associated disease. This is the first case of coronavirus granuloma described on CT-scan in the central nervous system of a ferret. © 2015 British Small Animal Veterinary Association.

  18. RNA metabolism in the regulation of protein synthesis in plants. Progress report, 1975-1979

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Key, J L

    1979-01-01

    The major objectives of the research for the contract period covered by this report were (1) to gain an insight into the sequence organization of the DNA of soybean, emphasizing the arrangement of single copy or unique sequences and repetitive sequences of DNA throughout the genome, (2) to characterize soybean RNAs relative to nucleotide sequence complexity and kinetics of synthesis and turnover of poly A/sup +/ mRNA, and (3) to study ribosomal proteins directed to an analysis of possible changes in proteins which relate to the activation of 80S ribosomes and thus mRNA utilization and protein synthesis in response tomore » environmental stimuli. Even with greatly reduced funding compared to that requested, objectives 1 and 2 were substantially accomplished. Because of reduced funding and the 20-month no cost extension, relatively little progress was made on objective 3. Accordingly objectives 1 and 2 will be summarized in some detail; a brief account of progress is presented on objective 3.« less

  19. Inhibition of host protein synthesis by Sindbis virus: correlation with viral RNA replication and release of nuclear proteins to the cytoplasm.

    PubMed

    Sanz, Miguel A; García-Moreno, Manuel; Carrasco, Luis

    2015-04-01

    Infection of mammalian cells by Sindbis virus (SINV) profoundly blocks cellular mRNA translation. Experimental evidence points to viral non-structural proteins (nsPs), in particular nsP2, as the mediator of this inhibition. However, individual expression of nsP1, nsP2, nsP3 or nsP1-4 does not block cellular protein synthesis in BHK cells. Trans-complementation of a defective SINV replicon lacking most of the coding region for nsPs by the co-expression of nsP1-4 propitiates viral RNA replication at low levels, and inhibition of cellular translation is not observed. Exit of nuclear proteins including T-cell intracellular antigen and polypyrimidine tract-binding protein is clearly detected in SINV-infected cells, but not upon the expression of nsPs, even when the defective replicon was complemented. Analysis of a SINV variant with a point mutation in nsP2, exhibiting defects in the shut-off of host protein synthesis, indicates that both viral RNA replication and the release of nuclear proteins to the cytoplasm are greatly inhibited. Furthermore, nucleoside analogues that inhibit cellular and viral RNA synthesis impede the blockade of host mRNA translation, in addition to the release of nuclear proteins. Prevention of the shut-off of host mRNA translation by nucleoside analogues is not due to the inhibition of eIF2α phosphorylation, as this prevention is also observed in PKR(-/-) mouse embryonic fibroblasts that do not phosphorylate eIF2α after SINV infection. Collectively, our observations are consistent with the concept that for the inhibition of cellular protein synthesis to occur, viral RNA replication must take place at control levels, leading to the release of nuclear proteins to the cytoplasm. © 2014 John Wiley & Sons Ltd.

  20. A method for detecting genetic toxicity using the RNA synthesis response to DNA damage.

    PubMed

    Morita, Yoko; Iwai, Shigenori; Kuraoka, Isao

    2011-10-01

    To date, biological risk assessment studies of chemicals that induce DNA lesions have been primarily based on the action of DNA polymerases during replication. However, DNA lesions interfere not only with replication but also with transcription. Therefore, detecting the damaging effects of DNA lesions during transcription might be important for estimating the safety of chemical mutagens and carcinogens. However, methods to address these effects have not been developed. Here, we report a simple, non-isotopic method for determining the toxicity of chemical agents by visualizing transcription in a mammalian cell system. The method is based on the measurement of the incorporation of bromouridine (as the uridine analogue) into the nascent RNA during RNA synthesis inhibition (RSI) induced by the stalling of RNA polymerases at DNA lesions on the transcribed DNA strand, which triggers transcription-coupled nucleotide excision repair (TC-NER). When we tested chemical agents (camptothecin, etoposide, 4-nitroquinoline-1-oxide, mitomycin C, methyl methanesulfonate, and cisplatin) in HeLa cells by the method, RSI indicative of genomic toxicity was observed in the nucleoli of the tested cells. This procedure provides the following advantages: 1) it uses common, affordable mammalian cells (HeLa cells, WI38VA13 cells, human dermal fibroblasts, or Chinese hamster ovary cells) rather than genetically modified microorganisms; 2) it can be completed within approximately 8 hr after the cells are prepared because RNA polymerase responses during TC-NER are faster than other DNA damage responses (replication, recombination, and apoptosis); and 3) it is safe because it uses non-radioactive bromouridine and antibodies to detect RNA synthesis on undamaged transcribed DNA strands.

  1. Template-directed synthesis using the heterogeneous templates produced by montmorillonite catalysis. A possible bridge between the prebiotic and RNA worlds

    NASA Technical Reports Server (NTRS)

    Ertem, G.; Ferris, J. P.

    1997-01-01

    The synthesis of oligoguanylates [oligo(G)s] is catalyzed by a template of oligocytidylates [oligo(C)s] containing 2',5'- and 3',5'-linked phosphodiester bonds with and without incorporated C5'ppC groupings. An oligo(C) template containing exclusively 2',5'-phosphodiester bonds also serves as a template for the synthesis of complementary oligo(G)s. The oligo(C) template was prepared by the condensation of the 5'-phosphorimidazolide of cytidine on montmorillonite clay. These studies establish that RNA oligomers prepared by mineral catalysis, or other routes on the primitive earth, did not have to be exclusively 3',5'-linked to catalyze template-directed synthesis, since oligo(C)s containing a variety of linkage isomers serve as templates for the formation of complementary oligo(G)s. These findings support the postulate that origin of the RNA world was initiated by the RNA oligomers produced by polymerization of activated monomers formed by prebiotic processes.

  2. Wheat DNA Primase (RNA Primer Synthesis in Vitro, Structural Studies by Photochemical Cross-Linking, and Modulation of Primase Activity by DNA Polymerases).

    PubMed Central

    Laquel, P.; Litvak, S.; Castroviejo, M.

    1994-01-01

    DNA primase synthesizes short RNA primers used by DNA polymerases to initiate DNA synthesis. Two proteins of approximately 60 and 50 kD were recognized by specific antibodies raised against yeast primase subunits, suggesting a high degree of analogy between wheat and yeast primase subunits. Gel-filtration chromatography of wheat primase showed two active forms of 60 and 110 to 120 kD. Ultraviolet-induced cross-linking with radioactive oligothymidilate revealed a highly labeled protein of 60 kD. After limited trypsin digestion of wheat (Triticum aestivum L.) primase, a major band of 48 kD and two minor bands of 38 and 17 kD were observed. In the absence of DNA polymerases, the purified primase synthesizes long RNA products. The size of the RNA product synthesized by wheat primase is considerably reduced by the presence of DNA polymerases, suggesting a modulatory effect of the association between these two enzymes. Lowering the primase concentration in the assay also favored short RNA primer synthesis. Several properties of the wheat DNA primase using oligoadenylate [oligo(rA)]-primed or unprimed polythymidilate templates were studied. The ability of wheat primase, without DNA polymerases, to elongate an oligo(rA) primer to long RNA products depends on the primer size, temperature, and the divalent cation concentration. Thus, Mn2+ ions led to long RNA products in a very wide range of concentrations, whereas with Mg2+ long products were observed around 15 mM. We studied the ability of purified wheat DNA polymerases to initiate DNA synthesis from an RNA primer: wheat DNA polymerase A showed the highest activity, followed by DNA polymerases B and CII, whereas DNA polymerase CI was unable to initiate DNA synthesis from an RNA primer. Results are discussed in terms of understanding the role of these polymerases in DNA replication in plants. PMID:12232187

  3. Reaction of cytidine nucleotides with cyanoacetylene: support for the intermediacy of nucleoside-2',3'-cyclic phosphates in the prebiotic synthesis of RNA.

    PubMed

    Crowe, Michael A; Sutherland, John D

    2006-06-01

    A robust and prebiotically plausible synthesis of RNA is a key requirement of the "RNA World" hypothesis, but, to date, no such synthesis has been demonstrated. Monomer synthesis strategies involving attachment of preformed nucleobases to sugars have failed, and, even if activated 5'-nucleotides could be made, the hydrolysis of these intermediates in water makes their efficient oligomerisation appear unlikely. We recently reported a synthesis of cytidine-2',3'-cyclic phosphate 1 (C>p) in which the nucleobase was assembled in stages on a sugar-phosphate template. However, 2',3'-cyclic nucleotides (N>p's) also undergo hydrolysis, in this case giving a mixture of the 2'- and 3'-monophosphates. This hydrolysis has previously been seen as making the, otherwise promising, oligomerisation of N>p's seem as unlikely as that of the 5'-activated nucleotides. We now find that cyanoacetylene, the reagent used for the second stage of nucleobase assembly in the synthesis of C>p, also reverses the effect of the hydrolysis by driving efficient cyclisation of C2'p and C3'p back to C>p. Excess cyanoacetylene also derivatises the nucleobase, but this modification is reversible at neutral pH. These findings significantly strengthen the case for N>p's in a prebiotic synthesis of RNA.

  4. A Mutation in the Bacillus subtilis rsbU Gene That Limits RNA Synthesis during Sporulation.

    PubMed

    Rothstein, David M; Lazinski, David; Osburne, Marcia S; Sonenshein, Abraham L

    2017-07-15

    Mutants of Bacillis subtilis that are temperature sensitive for RNA synthesis during sporulation were isolated after selection with a 32 P suicide agent. Whole-genome sequencing revealed that two of the mutants carried an identical lesion in the rsbU gene, which encodes a phosphatase that indirectly activates SigB, the stress-responsive RNA polymerase sigma factor. The mutation appeared to cause RsbU to be hyperactive, because the mutants were more resistant than the parent strain to ethanol stress. In support of this hypothesis, pseudorevertants that regained wild-type levels of sporulation at high temperature had secondary mutations that prevented expression of the mutant rsbU gene. The properties of these RsbU mutants support the idea that activation of SigB diminishes the bacterium's ability to sporulate. IMPORTANCE Most bacterial species encode multiple RNA polymerase promoter recognition subunits (sigma factors). Each sigma factor directs RNA polymerase to different sets of genes; each gene set typically encodes proteins important for responses to specific environmental conditions, such as changes in temperature, salt concentration, and nutrient availability. A selection for mutants of Bacillus subtilis that are temperature sensitive for RNA synthesis during sporulation unexpectedly yielded strains with a point mutation in rsbU , a gene that encodes a protein that normally activates sigma factor B (SigB) under conditions of salt stress. The mutation appears to cause RsbU, and therefore SigB, to be active inappropriately, thereby inhibiting, directly or indirectly, the ability of the cells to transcribe sporulation genes. Copyright © 2017 American Society for Microbiology.

  5. Feline coronavirus: Insights into viral pathogenesis based on the spike protein structure and function.

    PubMed

    Jaimes, Javier A; Whittaker, Gary R

    2018-04-01

    Feline coronavirus (FCoV) is an etiological agent that causes a benign enteric illness and the fatal systemic disease feline infectious peritonitis (FIP). The FCoV spike (S) protein is considered the viral regulator for binding and entry to the cell. This protein is also involved in FCoV tropism and virulence, as well as in the switch from enteric disease to FIP. This regulation is carried out by spike's major functions: receptor binding and virus-cell membrane fusion. In this review, we address important aspects in FCoV genetics, replication and pathogenesis, focusing on the role of S. To better understand this, FCoV S protein models were constructed, based on the human coronavirus NL63 (HCoV-NL63) S structure. We describe the specific structural characteristics of the FCoV S, in comparison with other coronavirus spikes. We also revise the biochemical events needed for FCoV S activation and its relation to the structural features of the protein. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Methylated nucleosides in tRNA and tRNA methyltransferases

    PubMed Central

    Hori, Hiroyuki

    2014-01-01

    To date, more than 90 modified nucleosides have been found in tRNA and the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent studies of the biosynthetic pathways have demonstrated that the availability of methyl group donors for the methylation in tRNA is important for correct and efficient protein synthesis. In this review, I focus on the methylated nucleosides and tRNA methyltransferases. The primary functions of tRNA methylations are linked to the different steps of protein synthesis, such as the stabilization of tRNA structure, reinforcement of the codon-anticodon interaction, regulation of wobble base pairing, and prevention of frameshift errors. However, beyond these basic functions, recent studies have demonstrated that tRNA methylations are also involved in the RNA quality control system and regulation of tRNA localization in the cell. In a thermophilic eubacterium, tRNA modifications and the modification enzymes form a network that responses to temperature changes. Furthermore, several modifications are involved in genetic diseases, infections, and the immune response. Moreover, structural, biochemical, and bioinformatics studies of tRNA methyltransferases have been clarifying the details of tRNA methyltransferases and have enabled these enzymes to be classified. In the final section, the evolution of modification enzymes is discussed. PMID:24904644

  7. Initiation, extension, and termination of RNA synthesis by a paramyxovirus polymerase.

    PubMed

    Jordan, Paul C; Liu, Cheng; Raynaud, Pauline; Lo, Michael K; Spiropoulou, Christina F; Symons, Julian A; Beigelman, Leo; Deval, Jerome

    2018-02-01

    Paramyxoviruses represent a family of RNA viruses causing significant human diseases. These include measles virus, the most infectious virus ever reported, in addition to parainfluenza virus, and other emerging viruses. Paramyxoviruses likely share common replication machinery but their mechanisms of RNA biosynthesis activities and details of their complex polymerase structures are unknown. Mechanistic and functional details of a paramyxovirus polymerase would have sweeping implications for understanding RNA virus replication and for the development of new antiviral medicines. To study paramyxovirus polymerase structure and function, we expressed an active recombinant Nipah virus (NiV) polymerase complex assembled from the multifunctional NiV L protein bound to its phosphoprotein cofactor. NiV is an emerging highly pathogenic virus that causes severe encephalitis and has been declared a global public health concern due to its high mortality rate. Using negative-stain electron microscopy, we demonstrated NiV polymerase forms ring-like particles resembling related RNA polymerases. We identified conserved sequence elements driving recognition of the 3'-terminal genomic promoter by NiV polymerase, and leading to initiation of RNA synthesis, primer extension, and transition to elongation mode. Polyadenylation resulting from NiV polymerase stuttering provides a mechanistic basis for transcription termination. It also suggests a divergent adaptation in promoter recognition between pneumo- and paramyxoviruses. The lack of available antiviral therapy for NiV prompted us to identify the triphosphate forms of R1479 and GS-5734, two clinically relevant nucleotide analogs, as substrates and inhibitors of NiV polymerase activity by delayed chain termination. Overall, these findings provide low-resolution structural details and the mechanism of an RNA polymerase from a previously uncharacterized virus family. This work illustrates important functional differences yet remarkable

  8. Detection of a novel human coronavirus by real-time reverse-transcription polymerase chain reaction.

    PubMed

    Corman, V M; Eckerle, I; Bleicker, T; Zaki, A; Landt, O; Eschbach-Bludau, M; van Boheemen, S; Gopal, R; Ballhause, M; Bestebroer, T M; Muth, D; Müller, M A; Drexler, J F; Zambon, M; Osterhaus, A D; Fouchier, R M; Drosten, C

    2012-09-27

    We present two real-time reverse-transcription polymerase chain reaction assays for a novel human coronavirus (CoV), targeting regions upstream of the E gene (upE) or within open reading frame (ORF)1b, respectively. Sensitivity for upE is 3.4 copies per reaction (95% confidence interval (CI): 2.5–6.9 copies) or 291 copies/mL of sample. No cross-reactivity was observed with coronaviruses OC43, NL63, 229E, SARS-CoV, nor with 92 clinical specimens containing common human respiratory viruses. We recommend using upE for screening and ORF1b for confirmation.

  9. RNA binding and replication by the poliovirus RNA polymerase

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Oberste, M.S.

    1988-01-01

    RNA binding and RNA synthesis by the poliovirus RNA-dependent RNA polymerase were studied in vitro using purified polymerase. Templates for binding and RNA synthesis studies were natural RNAs, homopolymeric RNAs, or subgenomic poliovirus-specific RNAs synthesized in vitro from cDNA clones using SP6 or T7 RNA polymerases. The binding of the purified polymerase to poliovirion and other RNAs was studied using a protein-RNA nitrocellulose filter binding assay. A cellular poly(A)-binding protein was found in the viral polymerase preparations, but was easily separated from the polymerase by chromatography on poly(A) Sepharose. The binding of purified polymerase to {sup 32}P-labeled ribohomopolymeric RNAs wasmore » examined, and the order of binding observed was poly(G) >>> poly(U) > poly(C) > poly(A). The K{sub a} for polymerase binding to poliovirion RNA and to a full-length negative strand transcript was about 1 {times} 10{sup 9} M{sup {minus}1}. The polymerase binds to a subgenomic RNAs which contain the 3{prime} end of the genome with a K{sub a} similar to that for virion RNA, but binds less well to 18S rRNA, globin mRNA, and subgenomic RNAs which lack portions of the 3{prime} noncoding region.« less

  10. Incubation period as part of the case definition of severe respiratory illness caused by a novel coronavirus.

    PubMed

    Nishiura, H; Mizumoto, K; Ejima, K; Zhong, Y; Cowling, Bj; Omori, R

    2012-10-18

    Non-specific symptoms of acute respiratory viral infections make it difficult for many countries without ongoing transmission of a novel coronavirus to rule out other possibilities including influenza before isolating imported febrile individuals with a possible exposure history. The incubation period helps differential diagnosis, and up to two days is suggestive of influenza. It is worth including the incubation period in the case definition of novel coronavirus infection.

  11. Recombinant protein-based assays for detection of antibodies to severe acute respiratory syndrome coronavirus spike and nucleocapsid proteins.

    PubMed

    Haynes, Lia M; Miao, Congrong; Harcourt, Jennifer L; Montgomery, Joel M; Le, Mai Quynh; Dryga, Sergey A; Kamrud, Kurt I; Rivers, Bryan; Babcock, Gregory J; Oliver, Jennifer Betts; Comer, James A; Reynolds, Mary; Uyeki, Timothy M; Bausch, Daniel; Ksiazek, Thomas; Thomas, William; Alterson, Harold; Smith, Jonathan; Ambrosino, Donna M; Anderson, Larry J

    2007-03-01

    Recombinant severe acute respiratory syndrome (SARS) nucleocapsid and spike protein-based immunoglobulin G immunoassays were developed and evaluated. Our assays demonstrated high sensitivity and specificity to the SARS coronavirus in sera collected from patients as late as 2 years postonset of symptoms. These assays will be useful not only for routine SARS coronavirus diagnostics but also for epidemiological and antibody kinetic studies.

  12. Association of seropositivity for influenza and coronaviruses with history of mood disorders and suicide attempts.

    PubMed

    Okusaga, Olaoluwa; Yolken, Robert H; Langenberg, Patricia; Lapidus, Manana; Arling, Timothy A; Dickerson, Faith B; Scrandis, Debra A; Severance, Emily; Cabassa, Johanna A; Balis, Theodora; Postolache, Teodor T

    2011-04-01

    Anecdotal reports of mood disorder following infection with common respiratory viruses with neurotropic potential have been in existence since the last century. Nevertheless, systematic studies on the association between these viruses and mood disorders are lacking. Influenza A, B and coronavirus antibody titers were measured in 257 subjects with recurrent unipolar and bipolar disorder and healthy controls, by SCID. Pearson's χ² tests and logistic regression models were used to analyze associations between seropositivity for coronaviruses, influenza A and B viruses and the following: a) history of recurrent mood disorders b) having attempted suicide in the past c) uni- vs. bi-polarity and d) presence of psychotic symptoms during mood episodes. Seropositivity for influenza A (p=0.004), B (p<0.0001) and coronaviruses (p<0.0001) were associated with history of mood disorders but not with the specific diagnosis of unipolar or bipolar depression. Seropositivity for influenza B was significantly associated with a history of suicide attempt (p=0.001) and history of psychotic symptoms (p=0.005). The design was cross-sectional. Socioeconomic factors, inflammatory markers, and axis II psychopathology were not assessed. The association of seropositivity for influenza and coronaviruses with a history of mood disorders, and influenza B with suicidal behavior require replication in larger longitudinal samples. The need for these studies is additionally supported by the high incidence of these viral infections, the high prevalence of mood disorders, and resilience of suicide epidemics. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. [Development of a SPA-ELISA method for detecting anti-coronavirus IgG antibodies in serum samples from fulvous fruit bats].

    PubMed

    Zhou, Jie; Liao, Yu-xue; Chen, Zhong; Li, Yu-chun; Gao, Lu-Lu; Chen, Yi-xiong; Cai, Lian-gong; Chen, Qing; Yu, Shou-yi

    2008-05-01

    To develop an simple and sensitive method for detecting anti-coronavirus IgG antibodies in bat sera based on enzyme-linked immunosorbent assay (ELISA). A commercial ELISA kit for detecting SARS-CoV antibody was modified for detecting coronavirus antibodies in bat serum samples. The second antibody in the kit was replaced with horseradish peroxidase-conjugated protein-A (HRP-SPA) based on the characteristics of binding between Staphylococcus aureus protein A (SPA) and mammal IgG Fc fragment. The sera of 55 fulvous fruit bats (Rousettus dasymallus) were tested using the SPA-ELISA. The test results of the positive and negative controls in the kit and the serum samples from convalescent ;patient were consistent with expectation. Coronavirus antibody was detected in 2 out of the 55 bat serum samples. Serum neutralization test confirmed the validity of the SPA-ELISA method. This SPA-ELISA method is applicable for detecting coronavirus antibody in bat sera.

  14. Sequence and structure-specific elements of HERG mRNA determine channel synthesis and trafficking efficiency

    PubMed Central

    Sroubek, Jakub; Krishnan, Yamini; McDonald, Thomas V.

    2013-01-01

    Human ether-á-gogo-related gene (HERG) encodes a potassium channel that is highly susceptible to deleterious mutations resulting in susceptibility to fatal cardiac arrhythmias. Most mutations adversely affect HERG channel assembly and trafficking. Why the channel is so vulnerable to missense mutations is not well understood. Since nothing is known of how mRNA structural elements factor in channel processing, we synthesized a codon-modified HERG cDNA (HERG-CM) where the codons were synonymously changed to reduce GC content, secondary structure, and rare codon usage. HERG-CM produced typical IKr-like currents; however, channel synthesis and processing were markedly different. Translation efficiency was reduced for HERG-CM, as determined by heterologous expression, in vitro translation, and polysomal profiling. Trafficking efficiency to the cell surface was greatly enhanced, as assayed by immunofluorescence, subcellular fractionation, and surface labeling. Chimeras of HERG-NT/CM indicated that trafficking efficiency was largely dependent on 5′ sequences, while translation efficiency involved multiple areas. These results suggest that HERG translation and trafficking rates are independently governed by noncoding information in various regions of the mRNA molecule. Noncoding information embedded within the mRNA may play a role in the pathogenesis of hereditary arrhythmia syndromes and could provide an avenue for targeted therapeutics.—Sroubek, J., Krishnan, Y., McDonald, T V. Sequence- and structure-specific elements of HERG mRNA determine channel synthesis and trafficking efficiency. PMID:23608144

  15. Serine Metabolism Supports the Methionine Cycle and DNA/RNA Methylation through De Novo ATP Synthesis in Cancer Cells

    PubMed Central

    Maddocks, Oliver D.K.; Labuschagne, Christiaan F.; Adams, Peter D.; Vousden, Karen H.

    2016-01-01

    Summary Crosstalk between cellular metabolism and the epigenome regulates epigenetic and metabolic homeostasis and normal cell behavior. Changes in cancer cell metabolism can directly impact epigenetic regulation and promote transformation. Here we analyzed the contribution of methionine and serine metabolism to methylation of DNA and RNA. Serine can contribute to this pathway by providing one-carbon units to regenerate methionine from homocysteine. While we observed this contribution under methionine-depleted conditions, unexpectedly, we found that serine supported the methionine cycle in the presence and absence of methionine through de novo ATP synthesis. Serine starvation increased the methionine/S-adenosyl methionine ratio, decreasing the transfer of methyl groups to DNA and RNA. While serine starvation dramatically decreased ATP levels, this was accompanied by lower AMP and did not activate AMPK. This work highlights the difference between ATP turnover and new ATP synthesis and defines a vital function of nucleotide synthesis beyond making nucleic acids. PMID:26774282

  16. Serine Metabolism Supports the Methionine Cycle and DNA/RNA Methylation through De Novo ATP Synthesis in Cancer Cells.

    PubMed

    Maddocks, Oliver D K; Labuschagne, Christiaan F; Adams, Peter D; Vousden, Karen H

    2016-01-21

    Crosstalk between cellular metabolism and the epigenome regulates epigenetic and metabolic homeostasis and normal cell behavior. Changes in cancer cell metabolism can directly impact epigenetic regulation and promote transformation. Here we analyzed the contribution of methionine and serine metabolism to methylation of DNA and RNA. Serine can contribute to this pathway by providing one-carbon units to regenerate methionine from homocysteine. While we observed this contribution under methionine-depleted conditions, unexpectedly, we found that serine supported the methionine cycle in the presence and absence of methionine through de novo ATP synthesis. Serine starvation increased the methionine/S-adenosyl methionine ratio, decreasing the transfer of methyl groups to DNA and RNA. While serine starvation dramatically decreased ATP levels, this was accompanied by lower AMP and did not activate AMPK. This work highlights the difference between ATP turnover and new ATP synthesis and defines a vital function of nucleotide synthesis beyond making nucleic acids. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Skeletal muscle plasticity induced by seasonal acclimatization in carp involves differential expression of rRNA and molecules that epigenetically regulate its synthesis.

    PubMed

    Fuentes, Eduardo N; Zuloaga, Rodrigo; Nardocci, Gino; Fernandez de la Reguera, Catalina; Simonet, Nicolas; Fumeron, Robinson; Valdes, Juan Antonio; Molina, Alfredo; Alvarez, Marco

    2014-01-01

    Ribosomal biogenesis controls cellular growth in living organisms, with the rate-limiting step of this process being the transcription of ribosomal DNA (rDNA). Considering that epigenetic mechanisms allow an organism to respond to environmental changes, the expression in muscle of several molecules that regulate epigenetic rRNA synthesis, as well as rDNA transcription, were evaluated during the seasonal acclimatization of the carp. First, the nucleotide sequences encoding the components forming the NoRC (ttf-I, tip5) and eNoSC (sirt1, nml, suv39h1), two chromatin remodeling complexes that silence rRNA synthesis, as well as the sequence of ubf1, a key regulator of rDNA transcription, were obtained. Subsequently the transcriptional regulation of the aforementioned molecules, and other key molecules involved in rRNA synthesis (mh2a1, mh2a2, h2a.z, h2a.z.7, nuc, p80), was assessed. The carp sequences for TTF-I, TIP5, SIRT1, NML, SUV39H1, and UBF1 showed a high conservation of domains and key amino acids in comparison with other fish and higher vertebrates. The mRNA contents in muscle for ttf-I, tip5, sirt1, nml, suv39h1, mh2a1, mh2a.z, and nuc were up-regulated during winter in comparison with summer, whereas the mRNA levels of mh2a2, ubf1, and p80 were down-regulated. Also, the contents of molecules involved in processing the rRNA (snoRNAs) and pRNA, a stabilizer of NoRC complex, were analyzed, finding that these non-coding RNAs were not affected by seasonal acclimatization. These results suggest that variations in the expression of rRNA and the molecules that epigenetically regulate its synthesis are contributing to the muscle plasticity induced by seasonal acclimatization in carp. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Overlapping and Distinct Molecular Determinants Dictating the Antiviral Activities of TRIM56 against Flaviviruses and Coronavirus

    PubMed Central

    Liu, Baoming; Li, Nan L.; Wang, Jie; Shi, Pei-Yong; Wang, Tianyi; Miller, Mark A.

    2014-01-01

    ABSTRACT The tripartite motif-containing (TRIM) proteins have emerged as a new class of host antiviral restriction factors, with several demonstrating roles in regulating innate antiviral responses. Of >70 known TRIMs, TRIM56 inhibits replication of bovine viral diarrhea virus, a ruminant pestivirus of the family Flaviviridae, but has no appreciable effect on vesicular stomatitis virus (VSV), a rhabdovirus. Yet the antiviral spectrum of TRIM56 remains undefined. In particular, how TRIM56 impacts human-pathogenic viruses is unknown. Also unclear are the molecular determinants governing the antiviral activities of TRIM56. Herein, we show that TRIM56 poses a barrier to infections by yellow fever virus (YFV), dengue virus serotype 2 (DENV2), and human coronavirus virus (HCoV) OC43 but not encephalomyocarditis virus (EMCV). Moreover, by engineering cell lines conditionally expressing various TRIM56 mutants, we demonstrated that TRIM56's antiflavivirus effects required both the E3 ligase activity that lies in the N-terminal RING domain and the integrity of its C-terminal portion, while the restriction of HCoV-OC43 relied upon the TRIM56 E3 ligase activity alone. Furthermore, TRIM56 was revealed to impair YFV and DENV2 propagation by suppressing intracellular viral RNA accumulation but to compromise HCoV-OC43 infection at a later step in the viral life cycle, suggesting that distinct TRIM56 domains accommodate differing antiviral mechanisms. Altogether, TRIM56 is a versatile antiviral host factor that confers resistance to YFV, DENV2, and HCoV-OC43 through overlapping and distinct molecular determinants. IMPORTANCE We previously reported tripartite motif protein 56 (TRIM56) as a host restriction factor of bovine viral diarrhea virus, a ruminant pathogen. However, the impact of TRIM56 on human-pathogenic RNA viruses is unknown. Herein, we demonstrate that TRIM56 restricts two medically important flaviviruses, yellow fever virus (YFV) and dengue virus serotype 2 (DENV2

  19. Overlapping and distinct molecular determinants dictating the antiviral activities of TRIM56 against flaviviruses and coronavirus.

    PubMed

    Liu, Baoming; Li, Nan L; Wang, Jie; Shi, Pei-Yong; Wang, Tianyi; Miller, Mark A; Li, Kui

    2014-12-01

    The tripartite motif-containing (TRIM) proteins have emerged as a new class of host antiviral restriction factors, with several demonstrating roles in regulating innate antiviral responses. Of >70 known TRIMs, TRIM56 inhibits replication of bovine viral diarrhea virus, a ruminant pestivirus of the family Flaviviridae, but has no appreciable effect on vesicular stomatitis virus (VSV), a rhabdovirus. Yet the antiviral spectrum of TRIM56 remains undefined. In particular, how TRIM56 impacts human-pathogenic viruses is unknown. Also unclear are the molecular determinants governing the antiviral activities of TRIM56. Herein, we show that TRIM56 poses a barrier to infections by yellow fever virus (YFV), dengue virus serotype 2 (DENV2), and human coronavirus virus (HCoV) OC43 but not encephalomyocarditis virus (EMCV). Moreover, by engineering cell lines conditionally expressing various TRIM56 mutants, we demonstrated that TRIM56's antiflavivirus effects required both the E3 ligase activity that lies in the N-terminal RING domain and the integrity of its C-terminal portion, while the restriction of HCoV-OC43 relied upon the TRIM56 E3 ligase activity alone. Furthermore, TRIM56 was revealed to impair YFV and DENV2 propagation by suppressing intracellular viral RNA accumulation but to compromise HCoV-OC43 infection at a later step in the viral life cycle, suggesting that distinct TRIM56 domains accommodate differing antiviral mechanisms. Altogether, TRIM56 is a versatile antiviral host factor that confers resistance to YFV, DENV2, and HCoV-OC43 through overlapping and distinct molecular determinants. We previously reported tripartite motif protein 56 (TRIM56) as a host restriction factor of bovine viral diarrhea virus, a ruminant pathogen. However, the impact of TRIM56 on human-pathogenic RNA viruses is unknown. Herein, we demonstrate that TRIM56 restricts two medically important flaviviruses, yellow fever virus (YFV) and dengue virus serotype 2 (DENV2), and a human

  20. RNA-dependent RNA polymerases of dsRNA bacteriophages.

    PubMed

    Makeyev, Eugene V; Grimes, Jonathan M

    2004-04-01

    Genome replication and transcription of riboviruses are catalyzed by an RNA-dependent RNA polymerase (RdRP). RdRPs are normally associated with other virus- or/and host-encoded proteins that modulate RNA polymerization activity and template specificity. The polymerase complex of double-stranded dsRNA viruses is a large icosahedral particle (inner core) containing RdRP as a minor constituent. In phi6 and other dsRNA bacteriophages from the Cystoviridae family, the inner core is composed of four virus-specific proteins. Of these, protein P2, or Pol subunit, has been tentatively identified as RdRP by sequence comparisons, but the role of this protein in viral RNA synthesis has not been studied until recently. Here, we overview the work on the Pol subunits of phi6 and related viruses from the standpoints of function, structure and evolution.

  1. Recombinant Protein-Based Assays for Detection of Antibodies to Severe Acute Respiratory Syndrome Coronavirus Spike and Nucleocapsid Proteins▿

    PubMed Central

    Haynes, Lia M.; Miao, Congrong; Harcourt, Jennifer L.; Montgomery, Joel M.; Le, Mai Quynh; Dryga, Sergey A.; Kamrud, Kurt I.; Rivers, Bryan; Babcock, Gregory J.; Oliver, Jennifer Betts; Comer, James A.; Reynolds, Mary; Uyeki, Timothy M.; Bausch, Daniel; Ksiazek, Thomas; Thomas, William; Alterson, Harold; Smith, Jonathan; Ambrosino, Donna M.; Anderson, Larry J.

    2007-01-01

    Recombinant severe acute respiratory syndrome (SARS) nucleocapsid and spike protein-based immunoglobulin G immunoassays were developed and evaluated. Our assays demonstrated high sensitivity and specificity to the SARS coronavirus in sera collected from patients as late as 2 years postonset of symptoms. These assays will be useful not only for routine SARS coronavirus diagnostics but also for epidemiological and antibody kinetic studies. PMID:17229882

  2. RNA synthetic mechanisms employed by diverse families of RNA viruses.

    PubMed

    McDonald, Sarah M

    2013-01-01

    RNA viruses are ubiquitous in nature, infecting every known organism on the planet. These viruses can also be notorious human pathogens with significant medical and economic burdens. Central to the lifecycle of an RNA virus is the synthesis of new RNA molecules, a process that is mediated by specialized virally encoded enzymes called RNA-dependent RNA polymerases (RdRps). RdRps directly catalyze phosphodiester bond formation between nucleoside triphosphates in an RNA-templated manner. These enzymes are strikingly conserved in their structural and functional features, even among diverse RNA viruses belonging to different families. During host cell infection, the activities of viral RdRps are often regulated by viral cofactor proteins. Cofactors can modulate the type and timing of RNA synthesis by directly engaging the RdRp and/or by indirectly affecting its capacity to recognize template RNA. High-resolution structures of RdRps as apoenzymes, bound to RNA templates, in the midst of catalysis, and/or interacting with regulatory cofactor proteins, have dramatically increased our understanding of viral RNA synthetic mechanisms. Combined with elegant biochemical studies, such structures are providing a scientific platform for the rational design of antiviral agents aimed at preventing and treating RNA virus-induced diseases. Copyright © 2013 John Wiley & Sons, Ltd.

  3. A two-way street: regulatory interplay between RNA polymerase and nascent RNA structure

    PubMed Central

    Zhang, Jinwei; Landick, Robert

    2016-01-01

    The vectorial (5′-to-3′ at varying velocity) synthesis of RNA by cellular RNA polymerases creates a rugged kinetic landscape, demarcated by frequent, sometimes long-lived pauses. In addition to myriad gene-regulatory roles, these pauses temporally and spatially program the co-transcriptional, hierarchical folding of biologically active RNAs. Conversely, these RNA structures, which form inside or near the RNA exit channel, interact with the polymerase and adjacent protein factors to influence RNA synthesis by modulating pausing, termination, antitermination, and slippage. Here we review the evolutionary origin, mechanistic underpinnings, and regulatory consequences of this interplay between RNA polymerase and nascent RNA structure. We categorize and attempt to rationalize the extensive linkage between the transcriptional machinery and its product, and provide a framework for future studies. PMID:26822487

  4. Genetically Diverse Coronaviruses in Wild Bird Populations of Northern England

    PubMed Central

    Savage, Carol; Naylor, Clive; Bennett, Malcolm; Chantrey, Julian; Jones, Richard

    2009-01-01

    Infectious bronchitis virus (IBV) causes a costly respiratory viral disease of chickens. The role of wild birds in the epidemiology of IBV is poorly understood. We detected diverse coronaviruses by PCR in wildfowl and wading birds in England. Sequence analysis showed some viruses to be related to IBV. PMID:19624927

  5. RNA-Dependent DNA Polymerase Activity of RNA Tumor Viruses II. Directing Influence of RNA in the Reaction

    PubMed Central

    Leis, Jonathan P.; Hurwitz, Jerard

    1972-01-01

    The role of ribonucleic acid (RNA) in deoxyribonucleic acid (DNA) synthesis with the purified DNA polymerase from the avian myeloblastosis virus has been studied. The polymerase catalyzes the synthesis of DNA in the presence of four deoxynucleoside triphosphates, Mg2+, and a variety of RNA templates including those isolated from avian myeloblastosis, Rous sarcoma, and Rauscher leukemia viruses; phages f2, MS2, and Qβ; and synthetic homopolymers such as polyadenylate·polyuridylic acid. The enzyme does not initiate the synthesis of new chains but incorporates deoxynucleotides at 3′ hydroxyl ends of primer strands. The product is an RNA·DNA hybrid in which the two polynucleotide components are covalently linked. Free DNA has not been detected among the products formed with the purified enzyme in vitro. The DNA synthesized with avian myeloblastosis virus RNA after alkaline hydrolysis has a sedimentation coefficient of 6 to 7S. PMID:4333539

  6. Synthesis, characterization, and evaluation of ionizable lysine-based lipids for siRNA delivery.

    PubMed

    Walsh, Colin L; Nguyen, Juliane; Tiffany, Matthew R; Szoka, Francis C

    2013-01-16

    We report the synthesis and characterization of a series of ionizable lysine-based lipids (ILL), novel lipids containing a lysine headgroup linked to a long-chain dialkylamine through an amide linkage at the lysine α-amine. These ILLs contain two ionizable amines and a carboxylate, and exhibit pH-dependent lipid ionization that varies with lipid structure. The synthetic scheme employed allows for the simple, orthogonal manipulation of lipids. This provides a method for the development of a compositionally diverse library with varying ionizable headgroups, tail structures, and linker regions. A focused library of four ILLs was synthesized to determine the impact of hydrophobic fluidity, lipid net charge, and lipid pK(a) on the biophysical and siRNA transfection characteristics of this new class of lipids. We found that manipulation of lipid structure impacts the protonation behavior, electrostatically driven membrane disruption, and ability to promote siRNA mediated knockdown in vitro. ILL-siRNA liposomal formulations were tested in a murine Factor VII model; however, no significant siRNA-mediated knockdown was observed. These results indicate that ILL may be useful in vitro transfection reagents, but further optimization of this new class of lipids is required to develop an effective in vivo siRNA delivery system.

  7. Severe Acute Respiratory Syndrome–associated Coronavirus Infection

    PubMed Central

    Ip, Margaret; Ng, KC; Wu, Alan; Lee, Nelson; Rainer, Timothy H.; Joynt, Gavin M.; Sung, Joseph J. Y.; Tam, John S.

    2003-01-01

    Whether severe acute respiratory syndrome–associated coronavirus (SARS-CoV) infection can be asymptomatic is unclear. We examined the seroprevalence of SARS-CoV among 674 healthcare workers from a hospital in which a SARS outbreak had occurred. A total of 353 (52%) experienced mild self-limiting illnesses, and 321 (48%) were asymptomatic throughout the course of these observations. None of these healthcare workers had antibody to SARS CoV, indicating that subclinical or mild infection attributable to SARS CoV in adults is rare. PMID:14718090

  8. Rat coronaviruses infect rat alveolar type I epithelial cells and induce expression of CXC chemokines

    PubMed Central

    Miura, Tanya A.; Wang, Jieru; Holmes, Kathryn V.; Mason, Robert J.

    2007-01-01

    We analyzed the ability of two rat coronavirus (RCoV) strains, sialodacryoadenitis virus (SDAV) and Parker’s RCoV (RCoV-P), to infect rat alveolar type I cells and induce chemokine expression. Primary rat alveolar type II cells were transdifferentiated into the type I cell phenotype. Type I cells were productively infected with SDAV and RCoV-P, and both live virus and UV-inactivated virus induced mRNA and protein expression of three CXC chemokines: CINC-2, CINC-3, and LIX, which are neutrophil chemoattractants. Dual immunolabeling of type I cells for viral antigen and CXC chemokines showed that chemokines were expressed primarily by uninfected cells. Virus-induced chemokine expression was reduced by the IL-1 receptor antagonist, suggesting that IL-1 produced by infected cells induces uninfected cells to express chemokines. Primary cultures of alveolar epithelial cells are an important model for the early events in viral infection that lead to pulmonary inflammation. PMID:17804032

  9. Properties of Native High-Density Lipoproteins Inspire Synthesis of Actively Targeted In Vivo siRNA Delivery Vehicles.

    PubMed

    McMahon, Kaylin M; Plebanek, Michael P; Thaxton, C Shad

    2016-11-15

    Efficient systemic administration of therapeutic short interfering RNA (siRNA) is challenging. High-density lipoproteins (HDL) are natural in vivo RNA delivery vehicles. Specifically, native HDLs: 1) Load single-stranded RNA; 2) Are anionic, which requires charge reconciliation between the RNA and HDL, and 3) Actively target scavenger receptor type B-1 (SR-B1) to deliver RNA. Emphasizing these particular parameters, we employed templated lipoprotein particles (TLP), mimics of spherical HDLs, and self-assembled them with single-stranded complements of, presumably, any highly unmodified siRNA duplex pair after formulation with a cationic lipid. Resulting siRNA templated lipoprotein particles (siRNA-TLP) are anionic and tunable with regard to RNA assembly and function. Data demonstrate that the siRNA-TLPs actively target SR-B1 to potently reduce androgen receptor (AR) and enhancer of zeste homolog 2 (EZH2) proteins in multiple cancer cell lines. Systemic administration of siRNA-TLPs demonstrated no off-target toxicity and significantly reduced the growth of prostate cancer xenografts. Thus, native HDLs inspired the synthesis of a hybrid siRNA delivery vehicle that can modularly load single-stranded RNA complements after charge reconciliation with a cationic lipid, and that function due to active targeting of SR-B1.

  10. Bovine coronavirus in naturally and experimentally exposed calves; viral shedding and the potential for transmission.

    PubMed

    Oma, Veslemøy Sunniva; Tråvén, Madeleine; Alenius, Stefan; Myrmel, Mette; Stokstad, Maria

    2016-06-13

    Bovine coronavirus (BCoV) is a widely distributed pathogen, causing disease and economic losses in the cattle industry worldwide. Prevention of virus spread is impeded by a lack of basic knowledge concerning viral shedding and transmission potential in individual animals. The aims of the study were to investigate the duration and quantity of BCoV shedding in feces and nasal secretions related to clinical signs, the presence of virus in blood and tissues and to test the hypothesis that seropositive calves are not infectious to naïve in-contact calves three weeks after BCoV infection. A live animal experiment was conducted, with direct contact between animal groups for 24 h as challenge procedure. Four naïve calves were commingled with a group of six naturally infected calves and sequentially euthanized. Two naïve sentinel calves were commingled with the experimentally exposed group three weeks after exposure. Nasal swabs, feces, blood and tissue samples were analyzed for viral RNA by RT-qPCR, and virus isolation was performed on nasal swabs. Serum was analyzed for BCoV antibodies. The calves showed mild general signs, and the most prominent signs were from the respiratory system. The overall clinical score corresponded well with the shedding of viral RNA the first three weeks after challenge. General depression and cough were the signs that correlated best with shedding of BCoV RNA, while peak respiratory rate and peak rectal temperature appeared more than a week later than the peak shedding. Nasal shedding preceded fecal shedding, and the calves had detectable amounts of viral RNA intermittently in feces through day 35 and in nasal secretions through day 28, however virus isolation was unsuccessful from day six and day 18 from the two calves investigated. Viral RNA was not detected in blood, but was found in lymphatic tissue through day 42 after challenge. Although the calves were shedding BCoV RNA 21 days after infection the sentinel animals were not infected

  11. Clinico-epidemiological characteristics of acute respiratory infections caused by coronavirus OC43, NL63 and 229E.

    PubMed

    Reina, J; López-Causapé, C; Rojo-Molinero, E; Rubio, R

    2014-12-01

    Acute respiratory infection is a very common condition in the general population. The majority of these infections are due to viruses. This study attempted to determine the clinical and epidemiological characteristics of adult patients with respiratory infection by the coronavirus OC43, NL63 and 229E. Between January 2013 and February 2014, we prospectively studied all patients with suspected clinical respiratory infection by taking throat swabs and performing a reverse transcription polymerase chain reaction in search of coronavirus. In 48 cases (7.0% of the 686 enrolled patients; 12.6% of the 381 in whom a virus was detected) the presence of a coronavirus demonstrated. In 24 cases, the virus was OC43 (50%); in 14 cases, the virus was NL63 (29%); and in 10 cases, the virus was 229E (21%). The mean age was 54.5 years, with a slight predominance of men. The most common clinical presentations were nonspecific influenza symptoms (43.7%), pneumonia (29.2%) and chronic obstructive pulmonary disease exacerbation (8.3%). Fifty-two percent of the patients required hospitalization, and 2 patients required intensive care. There were no deaths. Acute respiratory infections caused by coronavirus mainly affect middle-aged male smokers, who are often affected by previous diseases. The most common clinical picture has been nonspecific influenza symptoms. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  12. A Two-Way Street: Regulatory Interplay between RNA Polymerase and Nascent RNA Structure.

    PubMed

    Zhang, Jinwei; Landick, Robert

    2016-04-01

    The vectorial (5'-to-3' at varying velocity) synthesis of RNA by cellular RNA polymerases (RNAPs) creates a rugged kinetic landscape, demarcated by frequent, sometimes long-lived, pauses. In addition to myriad gene-regulatory roles, these pauses temporally and spatially program the co-transcriptional, hierarchical folding of biologically active RNAs. Conversely, these RNA structures, which form inside or near the RNA exit channel, interact with the polymerase and adjacent protein factors to influence RNA synthesis by modulating pausing, termination, antitermination, and slippage. Here, we review the evolutionary origin, mechanistic underpinnings, and regulatory consequences of this interplay between RNAP and nascent RNA structure. We categorize and rationalize the extensive linkage between the transcriptional machinery and its product, and provide a framework for future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Genome-wide mRNA processing in methanogenic archaea reveals post-transcriptional regulation of ribosomal protein synthesis

    PubMed Central

    Qi, Lei; Yue, Lei; Feng, Deqin; Qi, Fengxia

    2017-01-01

    Abstract Unlike stable RNAs that require processing for maturation, prokaryotic cellular mRNAs generally follow an ‘all-or-none’ pattern. Herein, we used a 5΄ monophosphate transcript sequencing (5΄P-seq) that specifically captured the 5΄-end of processed transcripts and mapped the genome-wide RNA processing sites (PSSs) in a methanogenic archaeon. Following statistical analysis and stringent filtration, we identified 1429 PSSs, among which 23.5% and 5.4% were located in 5΄ untranslated region (uPSS) and intergenic region (iPSS), respectively. A predominant uridine downstream PSSs served as a processing signature. Remarkably, 5΄P-seq detected overrepresented uPSS and iPSS in the polycistronic operons encoding ribosomal proteins, and the majority upstream and proximal ribosome binding sites, suggesting a regulatory role of processing on translation initiation. The processed transcripts showed increased stability and translation efficiency. Particularly, processing within the tricistronic transcript of rplA-rplJ-rplL enhanced the translation of rplL, which can provide a driving force for the 1:4 stoichiometry of L10 to L12 in the ribosome. Growth-associated mRNA processing intensities were also correlated with the cellular ribosomal protein levels, thereby suggesting that mRNA processing is involved in tuning growth-dependent ribosome synthesis. In conclusion, our findings suggest that mRNA processing-mediated post-transcriptional regulation is a potential mechanism of ribosomal protein synthesis and stoichiometry. PMID:28520982

  14. Cell host response to infection with novel human coronavirus EMC predicts potential antivirals and important differences with SARS coronavirus.

    PubMed

    Josset, Laurence; Menachery, Vineet D; Gralinski, Lisa E; Agnihothram, Sudhakar; Sova, Pavel; Carter, Victoria S; Yount, Boyd L; Graham, Rachel L; Baric, Ralph S; Katze, Michael G

    2013-04-30

    A novel human coronavirus (HCoV-EMC) was recently identified in the Middle East as the causative agent of a severe acute respiratory syndrome (SARS) resembling the illness caused by SARS coronavirus (SARS-CoV). Although derived from the CoV family, the two viruses are genetically distinct and do not use the same receptor. Here, we investigated whether HCoV-EMC and SARS-CoV induce similar or distinct host responses after infection of a human lung epithelial cell line. HCoV-EMC was able to replicate as efficiently as SARS-CoV in Calu-3 cells and similarly induced minimal transcriptomic changes before 12 h postinfection. Later in infection, HCoV-EMC induced a massive dysregulation of the host transcriptome, to a much greater extent than SARS-CoV. Both viruses induced a similar activation of pattern recognition receptors and the interleukin 17 (IL-17) pathway, but HCoV-EMC specifically down-regulated the expression of several genes within the antigen presentation pathway, including both type I and II major histocompatibility complex (MHC) genes. This could have an important impact on the ability of the host to mount an adaptive host response. A unique set of 207 genes was dysregulated early and permanently throughout infection with HCoV-EMC, and was used in a computational screen to predict potential antiviral compounds, including kinase inhibitors and glucocorticoids. Overall, HCoV-EMC and SARS-CoV elicit distinct host gene expression responses, which might impact in vivo pathogenesis and could orient therapeutic strategies against that emergent virus. Identification of a novel coronavirus causing fatal respiratory infection in humans raises concerns about a possible widespread outbreak of severe respiratory infection similar to the one caused by SARS-CoV. Using a human lung epithelial cell line and global transcriptomic profiling, we identified differences in the host response between HCoV-EMC and SARS-CoV. This enables rapid assessment of viral properties and the

  15. CRM1 and its ribosome export adaptor NMD3 localize to the nucleolus and affect rRNA synthesis.

    PubMed

    Bai, Baoyan; Moore, Henna M; Laiho, Marikki

    2013-01-01

    CRM1 is an export factor that together with its adaptor NMD3 transports numerous cargo molecules from the nucleus to cytoplasm through the nuclear pore. Previous studies have suggested that CRM1 and NMD3 are detected in the nucleolus. However, their localization with subnucleolar domains or participation in the activities of the nucleolus are unclear. We demonstrate here biochemically and using imaging analyses that CRM1 and NMD3 co-localize with nucleolar marker proteins in the nucleolus. In particular, their nucleolar localization is markedly increased by inhibition of RNA polymerase I (Pol I) transcription by actinomycin D or by silencing Pol I catalytic subunit, RPA194. We show that CRM1 nucleolar localization is dependent on its activity and the expression of NMD3, whereas NMD3 nucleolar localization is independent of CRM1. This suggests that NMD3 provides nucleolar tethering of CRM1. While inhibition of CRM1 by leptomycin B inhibited processing of 28S ribosomal (r) RNA, depletion of NMD3 did not, suggesting that their effects on 28S rRNA processing are distinct. Markedly, depletion of NMD3 and inhibition of CRM1 reduced the rate of pre-47S rRNA synthesis. However, their inactivation did not lead to nucleolar disintegration, a hallmark of Pol I transcription stress, suggesting that they do not directly regulate transcription. These results indicate that CRM1 and NMD3 have complex functions in pathways that couple rRNA synthetic and processing engines and that the rRNA synthesis rate may be adjusted according to proficiency in rRNA processing and export.

  16. Promoter for Sindbis virus RNA-dependent subgenomic RNA transcription.

    PubMed

    Levis, R; Schlesinger, S; Huang, H V

    1990-04-01

    Sindbis virus is a positive-strand RNA enveloped virus, a member of the Alphavirus genus of the Togaviridae family. Two species of mRNA are synthesized in cells infected with Sindbis virus; one, the 49S RNA, is the genomic RNA; the other, the 26S RNA, is a subgenomic RNA that is identical in sequence to the 3' one-third of the genomic RNA. Ou et al. (J.-H. Ou, C. M. Rice, L. Dalgarno, E. G. Strauss, and J. H. Strauss, Proc. Natl. Acad. Sci. USA 79:5235-5239, 1982) identified a highly conserved region 19 nucleotides upstream and 2 nucleotides downstream from the start of the 26S RNA and proposed that in the negative-strand template, these nucleotides compose the promoter for directing the synthesis of the subgenomic RNA. Defective interfering (DI) RNAs of Sindbis virus were used to test this proposal. A 227-nucleotide sequence encompassing 98 nucleotides upstream and 117 nucleotides downstream from the start site of the Sindbis virus subgenomic RNA was inserted into a DI genome. The DI RNA containing the insert was replicated and packaged in the presence of helper virus, and cells infected with these DI particles produced a subgenomic RNA of the size and sequence expected if the promoter was functional. The initiating nucleotide was identical to that used for Sindbis virus subgenomic mRNA synthesis. Deletion analysis showed that the minimal region required to detect transcription of a subgenomic RNA from the negative-strand template of a DI RNA was 18 or 19 nucleotides upstream and 5 nucleotides downstream from the start of the subgenomic RNA.

  17. Promoter for Sindbis virus RNA-dependent subgenomic RNA transcription.

    PubMed Central

    Levis, R; Schlesinger, S; Huang, H V

    1990-01-01

    Sindbis virus is a positive-strand RNA enveloped virus, a member of the Alphavirus genus of the Togaviridae family. Two species of mRNA are synthesized in cells infected with Sindbis virus; one, the 49S RNA, is the genomic RNA; the other, the 26S RNA, is a subgenomic RNA that is identical in sequence to the 3' one-third of the genomic RNA. Ou et al. (J.-H. Ou, C. M. Rice, L. Dalgarno, E. G. Strauss, and J. H. Strauss, Proc. Natl. Acad. Sci. USA 79:5235-5239, 1982) identified a highly conserved region 19 nucleotides upstream and 2 nucleotides downstream from the start of the 26S RNA and proposed that in the negative-strand template, these nucleotides compose the promoter for directing the synthesis of the subgenomic RNA. Defective interfering (DI) RNAs of Sindbis virus were used to test this proposal. A 227-nucleotide sequence encompassing 98 nucleotides upstream and 117 nucleotides downstream from the start site of the Sindbis virus subgenomic RNA was inserted into a DI genome. The DI RNA containing the insert was replicated and packaged in the presence of helper virus, and cells infected with these DI particles produced a subgenomic RNA of the size and sequence expected if the promoter was functional. The initiating nucleotide was identical to that used for Sindbis virus subgenomic mRNA synthesis. Deletion analysis showed that the minimal region required to detect transcription of a subgenomic RNA from the negative-strand template of a DI RNA was 18 or 19 nucleotides upstream and 5 nucleotides downstream from the start of the subgenomic RNA. Images PMID:2319651

  18. Cyclooxygenase activity is important for efficient replication of mouse hepatitis virus at an early stage of infection

    PubMed Central

    Raaben, Matthijs; Einerhand, Alexandra WC; Taminiau, Lucas JA; van Houdt, Michel; Bouma, Janneke; Raatgeep, Rolien H; Büller, Hans A; de Haan, Cornelis AM; Rossen, John WA

    2007-01-01

    Cyclooxygenases (COXs) play a significant role in many different viral infections with respect to replication and pathogenesis. Here we investigated the role of COXs in the mouse hepatitis coronavirus (MHV) infection cycle. Blocking COX activity by different inhibitors or by RNA interference affected MHV infection in different cells. The COX inhibitors reduced MHV infection at a post-binding step, but early in the replication cycle. Both viral RNA and viral protein synthesis were affected with subsequent loss of progeny virus production. Thus, COX activity appears to be required for efficient MHV replication, providing a potential target for anti-coronaviral therapy. PMID:17555580

  19. Prevalence and implications of feline coronavirus infections of captive and free-ranging cheetahs (Acinonyx jubatus).

    PubMed Central

    Heeney, J L; Evermann, J F; McKeirnan, A J; Marker-Kraus, L; Roelke, M E; Bush, M; Wildt, D E; Meltzer, D G; Colly, L; Lukas, J

    1990-01-01

    The extent and progression of exposure to feline infectious peritonitis (FIP) virus in the cheetah, Acinonyx jubatus, was monitored by a world-wide serological survey with indirect fluorescent antibody titers to coronavirus. The indirect fluorescent antibody assay was validated by Western blots, which showed that all indirect fluorescent antibody-positive cheetah sera detected both domestic cat and cheetah coronavirus structural proteins. There was a poor correlation between indirect fluorescent antibody results and the presence of coronaviruslike particles in cheetah feces, suggesting that electron microscopic detection of shed particles may not be an easily interpreted diagnostic parameter for FIP disease. Low, but verifiable (by Western blots [immunoblots]) antibody titers against coronavirus were detected in eight free-ranging cheetahs from east Africa as well as from captive cheetahs throughout the world. Of 20 North American cheetah facilities screened, 9 had cheetahs with measurable antibodies to feline coronavirus. Five facilities showed patterns of an ongoing epizootic. Retrospective FIP virus titers of an FIP outbreak in a cheetah-breeding facility in Oregon were monitored over a 5-year period and are interpreted here in terms of clinical disease progression. During that outbreak the morbidity was over 90% and the mortality was 60%, far greater than any previously reported epizootic of FIP in any cat species. Age of infection was a significant risk factor in this epizootic, with infants (less than 3 months old) displaying significantly higher risk for mortality than subadults or adults. Based upon these observations, empirical generalizations are drawn which address epidemiologic concerns for cheetahs in the context of this lethal infectious agent. Images PMID:2157864

  20. The Role of Severe Acute Respiratory Syndrome (SARS)-Coronavirus Accessory Proteins in Virus Pathogenesis

    PubMed Central

    McBride, Ruth; Fielding, Burtram C.

    2012-01-01

    A respiratory disease caused by a novel coronavirus, termed the severe acute respiratory syndrome coronavirus (SARS-CoV), was first reported in China in late 2002. The subsequent efficient human-to-human transmission of this virus eventually affected more than 30 countries worldwide, resulting in a mortality rate of ~10% of infected individuals. The spread of the virus was ultimately controlled by isolation of infected individuals and there has been no infections reported since April 2004. However, the natural reservoir of the virus was never identified and it is not known if this virus will re-emerge and, therefore, research on this virus continues. The SARS-CoV genome is about 30 kb in length and is predicted to contain 14 functional open reading frames (ORFs). The genome encodes for proteins that are homologous to known coronavirus proteins, such as the replicase proteins (ORFs 1a and 1b) and the four major structural proteins: nucleocapsid (N), spike (S), membrane (M) and envelope (E). SARS-CoV also encodes for eight unique proteins, called accessory proteins, with no known homologues. This review will summarize the current knowledge on SARS-CoV accessory proteins and will include: (i) expression and processing; (ii) the effects on cellular processes; and (iii) functional studies. PMID:23202509

  1. Release of Severe Acute Respiratory Syndrome Coronavirus Nuclear Import Block Enhances Host Transcription in Human Lung Cells

    PubMed Central

    Tilton, Susan C.; Menachery, Vineet D.; Gralinski, Lisa E.; Schäfer, Alexandra; Matzke, Melissa M.; Webb-Robertson, Bobbie-Jo M.; Chang, Jean; Luna, Maria L.; Long, Casey E.; Shukla, Anil K.; Bankhead, Armand R.; Burkett, Susan E.; Zornetzer, Gregory; Tseng, Chien-Te Kent; Metz, Thomas O.; Pickles, Raymond; McWeeney, Shannon; Smith, Richard D.; Katze, Michael G.; Waters, Katrina M.; Baric, Ralph S.

    2013-01-01

    The severe acute respiratory syndrome coronavirus accessory protein ORF6 antagonizes interferon signaling by blocking karyopherin-mediated nuclear import processes. Viral nuclear import antagonists, expressed by several highly pathogenic RNA viruses, likely mediate pleiotropic effects on host gene expression, presumably interfering with transcription factors, cytokines, hormones, and/or signaling cascades that occur in response to infection. By bioinformatic and systems biology approaches, we evaluated the impact of nuclear import antagonism on host expression networks by using human lung epithelial cells infected with either wild-type virus or a mutant that does not express ORF6 protein. Microarray analysis revealed significant changes in differential gene expression, with approximately twice as many upregulated genes in the mutant virus samples by 48 h postinfection, despite identical viral titers. Our data demonstrated that ORF6 protein expression attenuates the activity of numerous karyopherin-dependent host transcription factors (VDR, CREB1, SMAD4, p53, EpasI, and Oct3/4) that are critical for establishing antiviral responses and regulating key host responses during virus infection. Results were confirmed by proteomic and chromatin immunoprecipitation assay analyses and in parallel microarray studies using infected primary human airway epithelial cell cultures. The data strongly support the hypothesis that viral antagonists of nuclear import actively manipulate host responses in specific hierarchical patterns, contributing to the viral pathogenic potential in vivo. Importantly, these studies and modeling approaches not only provide templates for evaluating virus antagonism of nuclear import processes but also can reveal candidate cellular genes and pathways that may significantly influence disease outcomes following severe acute respiratory syndrome coronavirus infection in vivo. PMID:23365422

  2. Core Structure of S2 from the Human Coronavirus NL63 Spike Glycoprotein

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zheng,Q.; Deng, Y.; Liu, J.

    2006-01-01

    Human coronavirus NL63 (HCoV-NL63) has recently been identified as a causative agent of acute respiratory tract illnesses in infants and young children. The HCoV-NL63 spike (S) protein mediates virion attachment to cells and subsequent fusion of the viral and cellular membranes. This viral entry process is a primary target for vaccine and drug development. HCoV-NL63 S is expressed as a single-chain glycoprotein and consists of an N-terminal receptor-binding domain (S1) and a C-terminal transmembrane fusion domain (S2). The latter contains two highly conserved heptad-repeat (HR) sequences that are each extended by 14 amino acids relative to those of the SARSmore » coronavirus or the prototypic murine coronavirus, mouse hepatitis virus. Limited proteolysis studies of the HCoV-NL63 S2 fusion core identify an {alpha}-helical domain composed of a trimer of the HR segments N57 and C42. The crystal structure of this complex reveals three C42 helices entwined in an oblique and antiparallel manner around a central triple-stranded coiled coil formed by three N57 helices. The overall geometry comprises distinctive high-affinity conformations of interacting cross-sectional layers of the six helices. As a result, this structure is unusually stable, with an apparent melting temperature of 78 {sup o}C in the presence of the denaturant guanidine hydrochloride at 5 M concentration. The extended HR regions may therefore be required to prime the group 1 S glycoproteins for their fusion-activating conformational changes during viral entry. Our results provide an initial basis for understanding an intriguing interplay between the presence or absence of proteolytic maturation among the coronavirus groups and the membrane fusion activity of their S glycoproteins. This study also suggests a potential strategy for the development of improved HCoV-NL63 fusion inhibitors.« less

  3. Prophylaxis With a Middle East Respiratory Syndrome Coronavirus (MERS-CoV)–Specific Human Monoclonal Antibody Protects Rabbits From MERS-CoV Infection

    PubMed Central

    Houser, Katherine V.; Gretebeck, Lisa; Ying, Tianlei; Wang, Yanping; Vogel, Leatrice; Lamirande, Elaine W.; Bock, Kevin W.; Moore, Ian N.; Dimitrov, Dimiter S.; Subbarao, Kanta

    2016-01-01

    With >1600 documented human infections with Middle East respiratory syndrome coronavirus (MERS-CoV) and a case fatality rate of approximately 36%, medical countermeasures are needed to prevent and limit the disease. We examined the in vivo efficacy of the human monoclonal antibody m336, which has high neutralizing activity against MERS-CoV in vitro. m336 was administered to rabbits intravenously or intranasally before infection with MERS-CoV. Prophylaxis with m336 resulted in a reduction of pulmonary viral RNA titers by 40–9000-fold, compared with an irrelevant control antibody with little to no inflammation or viral antigen detected. This protection in rabbits supports further clinical development of m336. PMID:26941283

  4. Effects of S-adenosylmethionine decarboxylase, polyamines, amino acids, and weak bases (amines and ammonia) on development and ribosomal RNA synthesis in Xenopus embryos.

    PubMed

    Shiokawa, Koichiro; Aso, Mai; Kondo, Takeshi; Takai, Jun-Ichi; Yoshida, Junki; Mishina, Takamichi; Fuchimukai, Kota; Ogasawara, Tsukasa; Kariya, Taro; Tashiro, Kosuke; Igarashi, Kazuei

    2010-02-01

    We have been studying control mechanisms of gene expression in early embryogenesis in a South African clawed toad Xenopus laevis, especially during the period of midblastula transition (MBT), or the transition from the phase of active cell division (cleavage stage) to the phase of extensive morphogenesis (post-blastular stages). We first found that ribosomal RNA synthesis is initiated shortly after MBT in Xenopus embryos and those weak bases, such as amines and ammonium ion, selectively inhibit the initiation and subsequent activation of rRNA synthesis. We then found that rapidly labeled heterogeneous mRNA-like RNA is synthesized in embryos at pre-MBT stage. We then performed cloning and expression studies of several genes, such as those for activin receptors, follistatin and aldolases, and then reached the studies of S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in polyamine metabolism. Here, we cloned a Xenopus SAMDC cDNA and performed experiments to overexpress the in vitro-synthesized SAMDC mRNA in Xenopus early embryos, and found that the maternally preset program of apoptosis occurs in cleavage stage embryos, which is executed when embryos reach the stage of MBT. In the present article, we first summarize results on SAMDC and the maternal program of apoptosis, and then describe our studies on small-molecular-weight substances like polyamines, amino acids, and amines in Xenopus embryos. Finally, we summarize our studies on weak bases, especially on ammonium ion, as the specific inhibitor of ribosomal RNA synthesis in Xenopus embryonic cells.

  5. Cdk7 mediates RPB1-driven mRNA synthesis in Toxoplasma gondii

    PubMed Central

    Deshmukh, Abhijit S.; Mitra, Pallabi; Maruthi, Mulaka

    2016-01-01

    Cyclin-dependent kinase 7 in conjunction with CyclinH and Mat1 activates cell cycle CDKs and is a part of the general transcription factor TFIIH. Role of Cdk7 is well characterized in model eukaryotes however its relevance in protozoan parasites has not been investigated. This important regulator of key processes warrants closer examination particularly in this parasite given its unique cell cycle progression and flexible mode of replication. We report functional characterization of TgCdk7 and its partners TgCyclinH and TgMat1. Recombinant Cdk7 displays kinase activity upon binding its cyclin partner and this activity is further enhanced in presence of Mat1. The activated kinase phosphorylates C-terminal domain of TgRPB1 suggesting its role in parasite transcription. Therefore, the function of Cdk7 in CTD phosphorylation and RPB1 mediated transcription was investigated using Cdk7 inhibitor. Unphosphorylated CTD binds promoter DNA while phosphorylation by Cdk7 triggers its dissociation from DNA with implications for transcription initiation. Inhibition of Cdk7 in the parasite led to strong reduction in Serine 5 phosphorylation of TgRPB1-CTD at the promoters of constitutively expressed actin1 and sag1 genes with concomitant reduction of both nascent RNA synthesis and 5′-capped transcripts. Therefore, we provide compelling evidence for crucial role of TgCdk7 kinase activity in mRNA synthesis. PMID:27759017

  6. Two-amino acids change in the nsp4 of SARS coronavirus abolishes viral replication.

    PubMed

    Sakai, Yusuke; Kawachi, Kengo; Terada, Yutaka; Omori, Hiroko; Matsuura, Yoshiharu; Kamitani, Wataru

    2017-10-01

    Infection with coronavirus rearranges the host cell membrane to assemble a replication/transcription complex in which replication of the viral genome and transcription of viral mRNA occur. Although coexistence of nsp3 and nsp4 is known to cause membrane rearrangement, the mechanisms underlying the interaction of these two proteins remain unclear. We demonstrated that binding of nsp4 with nsp3 is essential for membrane rearrangement and identified amino acid residues in nsp4 responsible for the interaction with nsp3. In addition, we revealed that the nsp3-nsp4 interaction is not sufficient to induce membrane rearrangement, suggesting the participation of other factors such as host proteins. Finally, we showed that loss of the nsp3-nsp4 interaction eliminated viral replication by using an infectious cDNA clone and replicon system of SARS-CoV. These findings provide clues to the mechanism of the replication/transcription complex assembly of SARS-CoV and could reveal an antiviral target for the treatment of betacoronavirus infection. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Host cell entry of Middle East respiratory syndrome coronavirus after two-step, furin-mediated activation of the spike protein

    PubMed Central

    Millet, Jean Kaoru; Whittaker, Gary R.

    2014-01-01

    Middle East respiratory syndrome coronavirus (MERS-CoV) is a newly identified betacoronavirus causing high morbidity and mortality in humans. The coronavirus spike (S) protein is the main determinant of viral entry, and although it was previously shown that MERS-CoV S can be activated by various proteases, the details of the mechanisms of proteolytic activation of fusion are still incompletely characterized. Here, we have uncovered distinctive characteristics of MERS-CoV S. We identify, by bioinformatics and peptide cleavage assays, two cleavage sites for furin, a ubiquitously expressed protease, which are located at the S1/S2 interface and at the S2′ position of the S protein. We show that although the S1/S2 site is proteolytically processed by furin during protein biosynthesis, the S2′ site is cleaved upon viral entry. MERS-CoV pseudovirion infection was shown to be enhanced by elevated levels of furin expression, and entry could be decreased by furin siRNA silencing. Enhanced furin activity appeared to partially override the low pH-dependent nature of MERS-CoV entry. Inhibition of furin activity was shown to decrease MERS-CoV S-mediated entry, as well as infection by the virus. Overall, we show that MERS-CoV has evolved an unusual two-step furin activation for fusion, suggestive of a role during the process of emergence into the human population. The ability of MERS-CoV to use furin in this manner, along with other proteases, may explain the polytropic nature of the virus. PMID:25288733

  8. 2'-O-methylation in mRNA disrupts tRNA decoding during translation elongation.

    PubMed

    Choi, Junhong; Indrisiunaite, Gabriele; DeMirci, Hasan; Ieong, Ka-Weng; Wang, Jinfan; Petrov, Alexey; Prabhakar, Arjun; Rechavi, Gideon; Dominissini, Dan; He, Chuan; Ehrenberg, Måns; Puglisi, Joseph D

    2018-03-01

    Chemical modifications of mRNA may regulate many aspects of mRNA processing and protein synthesis. Recently, 2'-O-methylation of nucleotides was identified as a frequent modification in translated regions of human mRNA, showing enrichment in codons for certain amino acids. Here, using single-molecule, bulk kinetics and structural methods, we show that 2'-O-methylation within coding regions of mRNA disrupts key steps in codon reading during cognate tRNA selection. Our results suggest that 2'-O-methylation sterically perturbs interactions of ribosomal-monitoring bases (G530, A1492 and A1493) with cognate codon-anticodon helices, thereby inhibiting downstream GTP hydrolysis by elongation factor Tu (EF-Tu) and A-site tRNA accommodation, leading to excessive rejection of cognate aminoacylated tRNAs in initial selection and proofreading. Our current and prior findings highlight how chemical modifications of mRNA tune the dynamics of protein synthesis at different steps of translation elongation.

  9. Genome-wide mRNA processing in methanogenic archaea reveals post-transcriptional regulation of ribosomal protein synthesis.

    PubMed

    Qi, Lei; Yue, Lei; Feng, Deqin; Qi, Fengxia; Li, Jie; Dong, Xiuzhu

    2017-07-07

    Unlike stable RNAs that require processing for maturation, prokaryotic cellular mRNAs generally follow an 'all-or-none' pattern. Herein, we used a 5΄ monophosphate transcript sequencing (5΄P-seq) that specifically captured the 5΄-end of processed transcripts and mapped the genome-wide RNA processing sites (PSSs) in a methanogenic archaeon. Following statistical analysis and stringent filtration, we identified 1429 PSSs, among which 23.5% and 5.4% were located in 5΄ untranslated region (uPSS) and intergenic region (iPSS), respectively. A predominant uridine downstream PSSs served as a processing signature. Remarkably, 5΄P-seq detected overrepresented uPSS and iPSS in the polycistronic operons encoding ribosomal proteins, and the majority upstream and proximal ribosome binding sites, suggesting a regulatory role of processing on translation initiation. The processed transcripts showed increased stability and translation efficiency. Particularly, processing within the tricistronic transcript of rplA-rplJ-rplL enhanced the translation of rplL, which can provide a driving force for the 1:4 stoichiometry of L10 to L12 in the ribosome. Growth-associated mRNA processing intensities were also correlated with the cellular ribosomal protein levels, thereby suggesting that mRNA processing is involved in tuning growth-dependent ribosome synthesis. In conclusion, our findings suggest that mRNA processing-mediated post-transcriptional regulation is a potential mechanism of ribosomal protein synthesis and stoichiometry. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Saracatinib Inhibits Middle East Respiratory Syndrome-Coronavirus Replication In Vitro.

    PubMed

    Shin, Jin Soo; Jung, Eunhye; Kim, Meehyein; Baric, Ralph S; Go, Yun Young

    2018-05-24

    The Middle East respiratory syndrome-coronavirus (MERS-CoV), first identified in Saudi Arabia, is an emerging zoonotic pathogen that causes severe acute respiratory illness in humans with a high fatality rate. Since its emergence, MERS-CoV continues to spread to countries outside of the Arabian Peninsula and gives rise to sporadic human infections following the entry of infected individuals to other countries, which can precipitate outbreaks similar to the one that occurred in South Korea in 2015. Current therapeutics against MERS-CoV infection have primarily been adapted from previous drugs used for the treatment of severe acute respiratory syndrome. In search of new potential drug candidates, we screened a library composed of 2334 clinically approved drugs and pharmacologically active compounds. The drug saracatinib, a potent inhibitor of Src-family of tyrosine kinases (SFK), was identified as an inhibitor of MERS-CoV replication in vitro. Our results suggest that saracatinib potently inhibits MERS-CoV at the early stages of the viral life cycle in Huh-7 cells, possibly through the suppression of SFK signaling pathways. Furthermore, saracatinib exhibited a synergistic effect with gemcitabine, an anticancer drug with antiviral activity against several RNA viruses. These data indicate that saracatinib alone or in combination with gemcitabine can provide a new therapeutic option for the treatment of MERS-CoV infection.

  11. Interconnections between mRNA degradation and RDR-dependent siRNA production in mRNA turnover in plants.

    PubMed

    Tsuzuki, Masayuki; Motomura, Kazuki; Kumakura, Naoyoshi; Takeda, Atsushi

    2017-03-01

    Accumulation of an mRNA species is determined by the balance between the synthesis and the degradation of the mRNA. Individual mRNA molecules are selectively and actively degraded through RNA degradation pathways, which include 5'-3' mRNA degradation pathway, 3'-5' mRNA degradation pathway, and RNA-dependent RNA polymerase-mediated mRNA degradation pathway. Recent studies have revealed that these RNA degradation pathways compete with each other in mRNA turnover in plants and that plants have a hidden layer of non-coding small-interfering RNA production from a set of mRNAs. In this review, we summarize the current information about plant mRNA degradation pathways in mRNA turnover and discuss the potential roles of a novel class of the endogenous siRNAs derived from plant mRNAs.

  12. Cell Host Response to Infection with Novel Human Coronavirus EMC Predicts Potential Antivirals and Important Differences with SARS Coronavirus

    PubMed Central

    Josset, Laurence; Menachery, Vineet D.; Gralinski, Lisa E.; Agnihothram, Sudhakar; Sova, Pavel; Carter, Victoria S.; Yount, Boyd L.; Graham, Rachel L.; Baric, Ralph S.; Katze, Michael G.

    2013-01-01

    ABSTRACT A novel human coronavirus (HCoV-EMC) was recently identified in the Middle East as the causative agent of a severe acute respiratory syndrome (SARS) resembling the illness caused by SARS coronavirus (SARS-CoV). Although derived from the CoV family, the two viruses are genetically distinct and do not use the same receptor. Here, we investigated whether HCoV-EMC and SARS-CoV induce similar or distinct host responses after infection of a human lung epithelial cell line. HCoV-EMC was able to replicate as efficiently as SARS-CoV in Calu-3 cells and similarly induced minimal transcriptomic changes before 12 h postinfection. Later in infection, HCoV-EMC induced a massive dysregulation of the host transcriptome, to a much greater extent than SARS-CoV. Both viruses induced a similar activation of pattern recognition receptors and the interleukin 17 (IL-17) pathway, but HCoV-EMC specifically down-regulated the expression of several genes within the antigen presentation pathway, including both type I and II major histocompatibility complex (MHC) genes. This could have an important impact on the ability of the host to mount an adaptive host response. A unique set of 207 genes was dysregulated early and permanently throughout infection with HCoV-EMC, and was used in a computational screen to predict potential antiviral compounds, including kinase inhibitors and glucocorticoids. Overall, HCoV-EMC and SARS-CoV elicit distinct host gene expression responses, which might impact in vivo pathogenesis and could orient therapeutic strategies against that emergent virus. PMID:23631916

  13. The tRNA methyltransferase Dnmt2 is required for accurate polypeptide synthesis during haematopoiesis.

    PubMed

    Tuorto, Francesca; Herbst, Friederike; Alerasool, Nader; Bender, Sebastian; Popp, Oliver; Federico, Giuseppina; Reitter, Sonja; Liebers, Reinhard; Stoecklin, Georg; Gröne, Hermann-Josef; Dittmar, Gunnar; Glimm, Hanno; Lyko, Frank

    2015-09-14

    The Dnmt2 enzyme utilizes the catalytic mechanism of eukaryotic DNA methyltransferases to methylate several tRNAs at cytosine 38. Dnmt2 mutant mice, flies, and plants were reported to be viable and fertile, and the biological function of Dnmt2 has remained elusive. Here, we show that endochondral ossification is delayed in newborn Dnmt2-deficient mice, which is accompanied by a reduction of the haematopoietic stem and progenitor cell population and a cell-autonomous defect in their differentiation. RNA bisulfite sequencing revealed that Dnmt2 methylates C38 of tRNA Asp(GTC), Gly(GCC), and Val(AAC), thus preventing tRNA fragmentation. Proteomic analyses from primary bone marrow cells uncovered systematic differences in protein expression that are due to specific codon mistranslation by tRNAs lacking Dnmt2-dependent methylation. Our observations demonstrate that Dnmt2 plays an important role in haematopoiesis and define a novel function of C38 tRNA methylation in the discrimination of near-cognate codons, thereby ensuring accurate polypeptide synthesis. © 2015 The Authors. Published under the terms of the CC BY NC ND 4.0 license.

  14. The antiviral protein Viperin suppresses T7 promoter dependent RNA synthesis-possible implications for its antiviral activity.

    PubMed

    Dukhovny, Anna; Shlomai, Amir; Sklan, Ella H

    2018-05-25

    Viperin is a multifunctional interferon-inducible broad-spectrum antiviral protein. Viperin belongs to the S-Adenosylmethionine (SAM) superfamily of enzymes known to catalyze a wide variety of radical-mediated reactions. However, the exact mechanism by which viperin exerts its functions is still unclear. Interestingly, for many RNA viruses viperin was shown to inhibit viral RNA accumulation by interacting with different viral non-structural proteins. Here, we show that viperin inhibits RNA synthesis by bacteriophage T7 polymerase in mammalian cells. This inhibition is specific and occurs at the RNA level. Viperin expression significantly reduced T7-mediated cytoplasmic RNA levels. The data showing that viperin inhibits the bacteriophage T7 polymerase supports the conservation of viperin's antiviral activity between species. These results highlight the possibility that viperin might utilize a broader mechanism of inhibition. Accordingly, our results suggest a novel mechanism involving polymerase inhibition and provides a tractable system for future mechanistic studies of viperin.

  15. Bovine coronavirus (BCV) infections in transported commingled beef cattle and sole-source ranch calves

    PubMed Central

    Fulton, Robert W.; Step, Douglas L.; Wahrmund, Jackie; Burge, Lurinda J.; Payton, Mark E.; Cook, Billy J.; Burken, Dirk; Richards, Chris J.; Confer, Anthony W.

    2011-01-01

    This study investigated bovine coronavirus (BCV) in both beef calves direct from the ranch and commingled, mixed-source calves obtained from an auction market. The level of BCV-neutralizing antibodies found in the calves varied among ranches in 2 different studies in a retained-ownership program (ROP), from the ranch to the feedlot. Calves with low levels of BCV-neutralizing antibodies (16 or less) were more likely to be treated for bovine respiratory disease (BRD) than those with higher titers. In 3 studies of commingled, mixed-source calves, BCV was recovered from calves at entry to the feedlot and the infections were cleared by day 8. The BCV was identified in lung samples [bronchoalveolar lavage (BAL) collection] as well as in nasal swabs. Calves with low levels of BCV-neutralizing antibodies at entry were most likely to be shedding BCV. Bovine coronavirus was isolated from both healthy and sick calves, but not from sick calves after 4 d arrival at the feedlot. Bovine coronavirus (BCV) should be considered along with other bovine respiratory viruses in the diagnosis of etiologies in bovine respiratory disease, especially for animals that become sick shortly after arrival. If approved vaccines are developed, it would be best to carry out vaccination programs before calves are weaned, giving them sufficient time to gain active immunity before commingling with other cattle. PMID:22210995

  16. Middle East Respiratory Syndrome Coronavirus Antibodies in Dromedary Camels, Bangladesh, 2015

    PubMed Central

    Islam, Ariful; Rostal, Melinda K.; Islam, Shariful; Rahman, Mohammed Ziaur; Hossain, Mohammed Enayet; Uzzaman, Mohammed Salim; Munster, Vincent J.; Peiris, Malik; Flora, Meerjady Sabrina; Rahman, Mahmudur; Daszak, Peter

    2018-01-01

    Dromedary camels are bred domestically and imported into Bangladesh. In 2015, of 55 camels tested for Middle East respiratory syndrome coronavirus in Dhaka, 17 (31%) were seropositive, including 1 bred locally. None were PCR positive. The potential for infected camels in urban markets could have public health implications and warrants further investigation. PMID:29664373

  17. Searching for animal models and potential target species for emerging pathogens: Experience gained from Middle East respiratory syndrome (MERS) coronavirus.

    PubMed

    Vergara-Alert, Júlia; Vidal, Enric; Bensaid, Albert; Segalés, Joaquim

    2017-06-01

    Emerging and re-emerging pathogens represent a substantial threat to public health, as demonstrated with numerous outbreaks over the past years, including the 2013-2016 outbreak of Ebola virus in western Africa. Coronaviruses are also a threat for humans, as evidenced in 2002/2003 with infection by the severe acute respiratory syndrome coronavirus (SARS-CoV), which caused more than 8000 human infections with 10% fatality rate in 37 countries. Ten years later, a novel human coronavirus (Middle East respiratory syndrome coronavirus, MERS-CoV), associated with severe pneumonia, arose in the Kingdom of Saudi Arabia. Until December 2016, MERS has accounted for more than 1800 cases and 35% fatality rate. Finding an animal model of disease is key to develop vaccines or antivirals against such emerging pathogens and to understand its pathogenesis. Knowledge of the potential role of domestic livestock and other animal species in the transmission of pathogens is of importance to understand the epidemiology of the disease. Little is known about MERS-CoV animal host range. In this paper, experimental data on potential hosts for MERS-CoV is reviewed. Advantages and limitations of different animal models are evaluated in relation to viral pathogenesis and transmission studies. Finally, the relevance of potential new target species is discussed.

  18. Antisense RNA: effect of ribosome binding sites, target location, size, and concentration on the translation of specific mRNA molecules.

    PubMed

    Daugherty, B L; Hotta, K; Kumar, C; Ahn, Y H; Zhu, J D; Pestka, S

    1989-01-01

    A series of plasmids were constructed to generate RNA complementary to the beta-galactosidase messenger RNA under control of the phage lambda PL promoter. These plasmids generate anti-lacZ mRNA bearing or lacking a synthetic ribosome binding site adjacent to the lambda PL promoter and/or the lacZ ribosome binding site in reverse orientation. Fragments of lacZ DNA from the 5' and/or the 3' region were used in these constructions. When these anti-mRNA molecules were produced in Escherichia coli 294, maximal inhibition of beta-galactosidase synthesis occurred when a functional ribosome binding site was present near the 5' end of the anti-mRNA and the anti-mRNA synthesized was complementary to the 5' region of the mRNA corresponding to the lacZ ribosome binding site and/or the 5'-coding sequence. Anti-mRNAs producing maximal inhibition of beta-galactosidase synthesis exhibited an anti-lacZ mRNA:normal lacZ mRNA ratio of 100:1 or higher. Those showing lower levels of inhibition exhibited much lower anti-lacZ mRNA:normal lacZ mRNA ratios. A functional ribosome binding site at the 5'-end was found to decrease the decay rate of the anti-lacZ mRNAs. In addition, the incorporation of a transcription terminator just downstream of the antisense segment provided for more efficient inhibition of lacZ mRNA translation due to synthesis of smaller and more abundant anti-lacZ mRNAs. The optimal constructions produced undetectable levels of beta-galactosidase synthesis.

  19. Ebola Virus VP35 Interaction with Dynein LC8 Regulates Viral RNA Synthesis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Luthra, Priya; Jordan, David S.; Leung, Daisy W.

    2015-03-04

    Ebola virus VP35 inhibits alpha/beta interferon production and functions as a viral polymerase cofactor. Previously, the 8-kDa cytoplasmic dynein light chain (LC8) was demonstrated to interact with VP35, but the functional consequences were unclear. Here we demonstrate that the interaction is direct and of high affinity and that binding stabilizes the VP35 N-terminal oligomerization domain and enhances viral RNA synthesis. Mutational analysis demonstrates that VP35 interaction is required for the functional effects of LC8.

  20. Risk factors for MERS coronavirus infection in dromedary camels in Burkina Faso, Ethiopia, and Morocco, 2015

    PubMed Central

    Miguel, Eve; Chevalier, Véronique; Ayelet, Gelagay; Ben Bencheikh, Med Nadir; Boussini, Hiver; Chu, Daniel KW; El Berbri, Ikhlass; Fassi-Fihri, Ouaffa; Faye, Bernard; Fekadu, Getnet; Grosbois, Vladimir; Ng, Bryan CY; Perera, Ranawaka APM; So, TY; Traore, Amadou; Roger, François; Peiris, Malik

    2017-01-01

    Understanding Middle East respiratory syndrome coronavirus (MERS-CoV) transmission in dromedary camels is important, as they consitute a source of zoonotic infection to humans. To identify risk factors for MERS-CoV infection in camels bred in diverse conditions in Burkina Faso, Ethiopia and Morocco, blood samples and nasal swabs were sampled in February–March 2015. A relatively high MERS-CoV RNA rate was detected in Ethiopia (up to 15.7%; 95% confidence interval (CI): 8.2–28.0), followed by Burkina Faso (up to 12.2%; 95% CI: 7–20.4) and Morocco (up to 7.6%; 95% CI: 1.9–26.1). The RNA detection rate was higher in camels bred for milk or meat than in camels for transport (p = 0.01) as well as in younger camels (p = 0.06). High seropositivity rates (up to 100%; 95% CI: 100–100 and 99.4%; 95% CI: 95.4–99.9) were found in Morocco and Ethiopia, followed by Burkina Faso (up to 84.6%; 95% CI: 77.2–89.9). Seropositivity rates were higher in large/medium herds (≥51 camels) than small herds (p = 0.061), in camels raised for meat or milk than for transport (p = 0.01), and in nomadic or sedentary herds than in herds with a mix of these lifestyles (p < 0.005). PMID:28382915

  1. Risk factors for MERS coronavirus infection in dromedary camels in Burkina Faso, Ethiopia, and Morocco, 2015.

    PubMed

    Miguel, Eve; Chevalier, Véronique; Ayelet, Gelagay; Ben Bencheikh, Med Nadir; Boussini, Hiver; Chu, Daniel Kw; El Berbri, Ikhlass; Fassi-Fihri, Ouaffa; Faye, Bernard; Fekadu, Getnet; Grosbois, Vladimir; Ng, Bryan Cy; Perera, Ranawaka Apm; So, T Y; Traore, Amadou; Roger, François; Peiris, Malik

    2017-03-30

    Understanding Middle East respiratory syndrome coronavirus (MERS-CoV) transmission in dromedary camels is important, as they consitute a source of zoonotic infection to humans. To identify risk factors for MERS-CoV infection in camels bred in diverse conditions in Burkina Faso, Ethiopia and Morocco, blood samples and nasal swabs were sampled in February-March 2015. A relatively high MERS-CoV RNA rate was detected in Ethiopia (up to 15.7%; 95% confidence interval (CI): 8.2-28.0), followed by Burkina Faso (up to 12.2%; 95% CI: 7-20.4) and Morocco (up to 7.6%; 95% CI: 1.9-26.1). The RNA detection rate was higher in camels bred for milk or meat than in camels for transport (p = 0.01) as well as in younger camels (p = 0.06). High seropositivity rates (up to 100%; 95% CI: 100-100 and 99.4%; 95% CI: 95.4-99.9) were found in Morocco and Ethiopia, followed by Burkina Faso (up to 84.6%; 95% CI: 77.2-89.9). Seropositivity rates were higher in large/medium herds (≥51 camels) than small herds (p = 0.061), in camels raised for meat or milk than for transport (p = 0.01), and in nomadic or sedentary herds than in herds with a mix of these lifestyles (p < 0.005). This article is copyright of The Authors, 2017.

  2. Synthesis and Multiple Incorporations of 2′‐O‐Methyl‐5‐hydroxymethylcytidine, 5‐Hydroxymethylcytidine and 5‐Formylcytidine Monomers into RNA Oligonucleotides

    PubMed Central

    Tanpure, Arun A.

    2017-01-01

    Abstract The synthesis of 2′‐O‐methyl‐5‐hydroxymethylcytidine (hm5Cm), 5‐hydroxymethylcytidine (hm5C) and 5‐formylcytidine (f5C) phosphoramidite monomers has been developed. Optimisation of mild post‐synthetic deprotection conditions enabled the synthesis of RNA containing all four naturally occurring cytosine modifications (hm5Cm, hm5C, f5C plus 5‐methylcytosine). Given the considerable interest in RNA modifications and epitranscriptomics, the availability of synthetic monomers and RNAs containing these modifications will be valuable for elucidating their biological function(s). PMID:28901692

  3. Enteric disease in postweaned beef calves associated with a Bovine coronavirus clade 2

    USDA-ARS?s Scientific Manuscript database

    Bovine coronavirus (BoCV) infections are associated with varied clinical presentations including neonatal diarrhea, winter dysentery in dairy cattle, and respiratory disease in various ages of cattle. This report presents information on BoCV infections associated with enteric disease of postweaned b...

  4. Inhibition of selenocysteine tRNA[Ser]Sec aminoacylation provides evidence that aminoacylation is required for regulatory methylation of this tRNA

    PubMed Central

    Kim, Jin Young; Carlson, Bradley A.; Xu, Xue-Ming; Zeng, Yu; Chen, Shawn; Gladyshev, Vadim N.; Lee, Byeong Jae; Hatfield, Dolph L.

    2011-01-01

    There are two isoforms of selenocysteine (Sec) tRNA[Ser]Sec that differ by a single methyl group, Um34. The non-Um34 isoform supports the synthesis of a subclass of selenoproteins, designated housekeeping, while the Um34 isoform supports the expression of another subclass, designated stress-related selenoproteins. Herein, we investigated the relationship between tRNA[Ser]Sec aminoacylation and Um34 synthesis which is the last step in the maturation of this tRNA. Mutation of the discriminator base at position 73 in tRNA[Ser]Sec dramatically reduced aminoacylation with serine, as did an inhibitor of seryl-tRNA synthetase, SB-217452. Although both the mutation and the inhibitor prevented Um34 synthesis, neither precluded the synthesis of any other of the known base modifications on tRNA[Ser]Sec following microinjection and incubation of the mutant tRNA[Ser]Sec transcript, or the wild type transcript along with inhibitor, in Xenopus oocytes. The data demonstrate that Sec tRNA[Ser]Sec must be aminoacylated for Um34 addition. The fact that selenium is required for Um34 methylation suggests that Sec must be attached to its tRNA for Um34 methylation. This would explain why selenium is essential for the function of Um34 methylase and provides further insights into the hierarchy of selenoprotein expression. PMID:21624347

  5. Orotidine-Containing RNA: Implications for the Hierarchical Selection (Systems Chemistry Emergence) of RNA.

    PubMed

    Kim, Eun-Kyong; Martin, Vincent; Krishnamurthy, Ramanarayanan

    2017-09-12

    The prebiotic synthesis of canonical nucleobases from HCN is a cornerstone for the RNA world hypothesis. However, their role in the primordial pathways to RNA is still debated. The very same process starting from HCN also gives rise to orotic acid, which (via orotidine) plays a crucial role in extant biology in the de novo synthesis of uridine and cytidine, the informational base-pairs in RNA. However, orotidine itself is absent in RNA. Given the prebiotic and biological relevance of orotic acid vis-à-vis uracil, we investigated orotidine-containing RNA oligonucleotides and show that they have severely compromised base-pairing properties. While not unexpected, these results suggest that the emergence of extant RNA cannot just be a consequence of the plausible prebiotic formation of its chemical constituents/building blocks. In combination with other investigations on alternative prebiotic nucleobases, sugars, and linkers, these findings imply that the selection of the components of extant RNA occurred at a higher hierarchical level of an oligomer/polymer based on its functional properties-pointing to a systems chemistry emergence of RNA from a library of precursors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Coronavirus and paramyxovirus in bats from Northwest Italy.

    PubMed

    Rizzo, Francesca; Edenborough, Kathryn M; Toffoli, Roberto; Culasso, Paola; Zoppi, Simona; Dondo, Alessandro; Robetto, Serena; Rosati, Sergio; Lander, Angelika; Kurth, Andreas; Orusa, Riccardo; Bertolotti, Luigi; Mandola, Maria Lucia

    2017-12-22

    Bat-borne virus surveillance is necessary for determining inter-species transmission risks and is important due to the wide-range of bat species which may harbour potential pathogens. This study aimed to monitor coronaviruses (CoVs) and paramyxoviruses (PMVs) in bats roosting in northwest Italian regions. Our investigation was focused on CoVs and PMVs due to their proven ability to switch host and their zoonotic potential. Here we provide the phylogenetic characterization of the highly conserved polymerase gene fragments. Family-wide PCR screenings were used to test 302 bats belonging to 19 different bat species. Thirty-eight animals from 12 locations were confirmed as PCR positive, with an overall detection rate of 12.6% [95% CI: 9.3-16.8]. CoV RNA was found in 36 bats belonging to eight species, while PMV RNA in three Pipistrellus spp. Phylogenetic characterization have been obtained for 15 alpha- CoVs, 5 beta-CoVs and three PMVs; moreover one P. pipistrellus resulted co-infected with both CoV and PMV. A divergent alpha-CoV clade from Myotis nattereri SpA is also described. The compact cluster of beta-CoVs from R. ferrumequinum roosts expands the current viral sequence database, specifically for this species in Europe. To our knowledge this is the first report of CoVs in Plecotus auritus and M. oxygnathus, and of PMVs in P. kuhlii. This study identified alpha and beta-CoVs in new bat species and in previously unsurveyed Italian regions. To our knowledge this represents the first and unique report of PMVs in Italy. The 23 new bat genetic sequences presented will expand the current molecular bat-borne virus databases. Considering the amount of novel bat-borne PMVs associated with the emergence of zoonotic infections in animals and humans in the last years, the definition of viral diversity within European bat species is needed. Performing surveillance studies within a specific geographic area can provide awareness of viral burden where bats roost in close proximity

  7. Recovery from severe novel coronavirus infection.

    PubMed

    Albarrak, Ali M; Stephens, Gwen M; Hewson, Roger; Memish, Ziad A

    2012-12-01

    We describe the third confirmed case of novel coronavirus infection in a resident of the Arabian Peninsula. Our patient presented, as did 2 prior cases, with severe pneumonia and renal dysfunction requiring intensive care support including assisted ventilation. However, unlike the earlier cases, and despite underlying chronic disease and a single kidney, he survived his infection and has been discharged home. The Ministry of Health continues active surveillance for additional cases. As this case report goes to press, 2 additional confirmed cases have been identified in Riyadh, Saudi Arabia. Contact investigations are in progress. Future work will focus not only on the origin of the virus and mechanisms of transmission, but also the host factors that influence pathogenesis and prognosis.

  8. A non-isotopic assay uses bromouridine and RNA synthesis to detect DNA damage responses.

    PubMed

    Hasegawa, Mayu; Iwai, Shigenori; Kuraoka, Isao

    2010-06-17

    Individuals with inherited xeroderma pigmentosum (XP) disorder and Cockayne syndrome (CS) are deficient in nucleotide excision repair and experience hypersensitivity to sunlight. Although there are several diagnostic assays for these disorders, the recovery of RNA synthesis (RRS) assay that can discriminate between XP cells and CS cells is very laborious. Here, we report on a novel non-radioisotope RRS assay that uses bromouridine (a uridine analog) as an alternative to (3)H-uridine. This assay can easily detect RNA polymerase I transcription in nucleoli and RNA polymerase II transcription in nuclei. The non-RI RSS assay also can rapidly detect normal RRS activity in HeLa cells. Thus, this assay is useful as a novel and easy technique for CS diagnosis. Because RRS is thought to be related to transcription-coupled DNA repair, which is triggered by the blockage of transcriptional machinery by DNA lesions, this assay may be of use for analysis of DNA repair, transcription, and/or genetic toxicity. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Experiment K-6-11. Actin mRNA and cytochrome c mRNA concentrations in the tricepts brachia muscle of rats

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Morrison, P. R.; Thomason, D. B.; Oganov, V. S.

    1990-01-01

    It is well known that some skeletal muscles atrophy as a result of weightlessness (Steffen and Musacchia 1986) and as a result of hindlimb suspension (Tischler et al., 1985, Thomason et al., 1987). Because the content of protein is determined by the rates of protein synthesis and degradation, a decrease in protein synthesis rate, or an increase in the protein degradation, or changes in both could produce the atrophy. Indeed, an increased protein degradation (Tischler et al., 1985) and a decreased protein synthesis (Thomason et al., 1988) have been observed in skeletal muscles of suspended hindlimbs of rats. Any decrease in protein synthesis rate could be caused by decreases in mRNA concentrations. Such decreases in the concentration and content of alpha-actin mRNA and cytochrome c mRNA have been noted in skeletal muscles of hindlimb suspended rats (Babij and Booth, 1988). From these findings researchers hypothesized that alpha-actin mRNA and cytochrome c mRNA would decrease in the triceps brachia muscle of Cosmos 1887 rats.

  10. The nucleolus as a stress sensor: JNK2 inactivates the transcription factor TIF-IA and down-regulates rRNA synthesis.

    PubMed

    Mayer, Christine; Bierhoff, Holger; Grummt, Ingrid

    2005-04-15

    Cells respond to a variety of extracellular and intracellular forms of stress by down-regulating rRNA synthesis. We have investigated the mechanism underlying stress-dependent inhibition of RNA polymerase I (Pol I) transcription and show that the Pol I-specific transcription factor TIF-IA is inactivated upon stress. Inactivation is due to phosphorylation of TIF-IA by c-Jun N-terminal kinase (JNK) at a single threonine residue (Thr 200). Phosphorylation at Thr 200 impairs the interaction of TIF-IA with Pol I and the TBP-containing factor TIF-IB/SL1, thereby abrogating initiation complex formation. Moreover, TIF-IA is translocated from the nucleolus into the nucleoplasm. Substitution of Thr 200 by valine as well as knock-out of Jnk2 prevent inactivation and translocation of TIF-IA, leading to stress-resistance of Pol I transcription. Our data identify TIF-IA as a downstream target of the JNK pathway and suggest a critical role of JNK2 to protect rRNA synthesis against the harmful consequences of cellular stress.

  11. The search for a structural basis for therapeutic intervention against the SARS coronavirus

    NASA Astrophysics Data System (ADS)

    Bartlam, M.; Xue, X.; Rao, Z.

    2008-01-01

    The severe acute respiratory syndrome (SARS) coronavirus outbreak in 2003 had profound social and economic impacts worldwide. This review highlights the importance of structural biology and shows that structures for drug design can be rapidly determined in the event of an emerging infectious disease.

  12. Amino Acids 270 to 510 of the Severe Acute Respiratory Syndrome Coronavirus Spike Protein Are Required for Interaction with Receptor

    PubMed Central

    Babcock, Gregory J.; Esshaki, Diana J.; Thomas, William D.; Ambrosino, Donna M.

    2004-01-01

    A novel coronavirus, severe acute respiratory syndrome coronavirus (SARS-CoV), has recently been identified as the causative agent of severe acute respiratory syndrome (SARS). SARS-CoV appears similar to other coronaviruses in both virion structure and genome organization. It is known for other coronaviruses that the spike (S) glycoprotein is required for both viral attachment to permissive cells and for fusion of the viral envelope with the host cell membrane. Here we describe the construction and expression of a soluble codon-optimized SARS-CoV S glycoprotein comprising the first 1,190 amino acids of the native S glycoprotein (S1190). The codon-optimized and native S glycoproteins exhibit similar molecular weight as determined by Western blot analysis, indicating that synthetic S glycoprotein is modified correctly in a mammalian expression system. S1190 binds to the surface of Vero E6 cells, a cell permissive to infection, as demonstrated by fluorescence-activated cell sorter analysis, suggesting that S1190 maintains the biologic activity present in native S glycoprotein. This interaction is blocked with serum obtained from recovering SARS patients, indicating that the binding is specific. In an effort to map the ligand-binding domain of the SARS-CoV S glycoprotein, carboxy- and amino-terminal truncations of the S1190 glycoprotein were constructed. Amino acids 270 to 510 were the minimal receptor-binding region of the SARS-CoV S glycoprotein as determined by flow cytometry. We speculate that amino acids 1 to 510 of the SARS-CoV S glycoprotein represent a unique domain containing the receptor-binding site (amino acids 270 to 510), analogous to the S1 subunit of other coronavirus S glycoproteins. PMID:15078936

  13. Coordinated modulation of albumin synthesis and mRNA levels in cultured hepatoma cells by hydrocortisone and cyclic AMP analogs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brown, P.C.; Papaconstantinou, J.

    The treatment of Hepa-2 cells, a permanent mouse hepatoma cell line, for 72 h with hydrocortisone (10/sup -6/ M), N/sup 6/,O/sup 2/-dibutyryl cyclic AMP (10/sup -3/ M), or 8-bromo cyclic AMP(10/sup -3/ M) results in a 2-, 3-, or 4-fold increase, respectively, in rates of synthesis and secretion of mouse serum albumin. Simultaneous treatment with hydrocortisone and N/sup 6/,O/sup 2/-dibutyryl cyclic AMP results in a 10-fold stimulation in these parameters, an effect that is significantly more than additive for the two compounds tested. The number of albumin mRNA sequences, determined by hybridization of total cell RNA to albumin complementary DNA,more » was increased in direct proportion to the increases in albumin synthesis in all experiments. The relative rate of albumin synthesis approaches in vivo levels in cells treated simultaneously with hydrocortisone and N/sup 6/,O/sup 2/-dibutyryl cyclic AMP. We propose that these factors may be necessary to maintain the maximal level of differentiated function in the continuous culture of Hepa-2 cells.« less

  14. Photolithographic Synthesis of High-Density DNA and RNA Arrays on Flexible, Transparent, and Easily Subdivided Plastic Substrates.

    PubMed

    Holden, Matthew T; Carter, Matthew C D; Wu, Cheng-Hsien; Wolfer, Jamison; Codner, Eric; Sussman, Michael R; Lynn, David M; Smith, Lloyd M

    2015-11-17

    The photolithographic fabrication of high-density DNA and RNA arrays on flexible and transparent plastic substrates is reported. The substrates are thin sheets of poly(ethylene terephthalate) (PET) coated with cross-linked polymer multilayers that present hydroxyl groups suitable for conventional phosphoramidite-based nucleic acid synthesis. We demonstrate that by modifying array synthesis procedures to accommodate the physical and chemical properties of these materials, it is possible to synthesize plastic-backed oligonucleotide arrays with feature sizes as small as 14 μm × 14 μm and feature densities in excess of 125 000/cm(2), similar to specifications attainable using rigid substrates such as glass or glassy carbon. These plastic-backed arrays are tolerant to a wide range of hybridization temperatures, and improved synthetic procedures are described that enable the fabrication of arrays with sequences up to 50 nucleotides in length. These arrays hybridize with S/N ratios comparable to those fabricated on otherwise identical arrays prepared on glass or glassy carbon. This platform supports the enzymatic synthesis of RNA arrays and proof-of-concept experiments are presented showing that the arrays can be readily subdivided into smaller arrays (or "millichips") using common laboratory-scale laser cutting tools. These results expand the utility of oligonucleotide arrays fabricated on plastic substrates and open the door to new applications for these important bioanalytical tools.

  15. SARS-CoV ORF1b-encoded nonstructural proteins 12-16: replicative enzymes as antiviral targets.

    PubMed

    Subissi, Lorenzo; Imbert, Isabelle; Ferron, François; Collet, Axelle; Coutard, Bruno; Decroly, Etienne; Canard, Bruno

    2014-01-01

    The SARS (severe acute respiratory syndrome) pandemic caused ten years ago by the SARS-coronavirus (SARS-CoV) has stimulated a number of studies on the molecular biology of coronaviruses. This research has provided significant new insight into many mechanisms used by the coronavirus replication-transcription complex (RTC). The RTC directs and coordinates processes in order to replicate and transcribe the coronavirus genome, a single-stranded, positive-sense RNA of outstanding length (∼27-32kilobases). Here, we review the up-to-date knowledge on SARS-CoV replicative enzymes encoded in the ORF1b, i.e., the main RNA-dependent RNA polymerase (nsp12), the helicase/triphosphatase (nsp13), two unusual ribonucleases (nsp14, nsp15) and RNA-cap methyltransferases (nsp14, nsp16). We also review how these enzymes co-operate with other viral co-factors (nsp7, nsp8, and nsp10) to regulate their activity. These last ten years of research on SARS-CoV have considerably contributed to unravel structural and functional details of one of the most fascinating replication/transcription machineries of the RNA virus world. This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10years of research on highly pathogenic human coronaviruses". Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Fitness advantages conferred by the L20-interacting RNA cis-regulator of ribosomal protein synthesis in Bacillus subtilis.

    PubMed

    Babina, Arianne M; Parker, Darren J; Li, Gene-Wei; Meyer, Michelle M

    2018-06-20

    In many bacteria, ribosomal proteins autogenously repress their own expression by interacting with RNA structures typically located in the 5'-UTRs of their mRNA transcripts. This regulation is necessary to maintain a balance between ribosomal proteins and rRNA to ensure proper ribosome production. Despite advances in non-coding RNA discovery and validation of RNA-protein regulatory interactions, the selective pressures that govern the formation and maintenance of such RNA cis-regulators in the context of an organism remain largely undetermined. To examine the impact disruptions to this regulation have on bacterial fitness, we introduced point mutations that abolish ribosomal protein binding and regulation into the RNA structure that controls expression of ribosomal proteins L20 and L35 within the Bacillus subtilis genome. Our studies indicate that removing this regulation results in reduced log phase growth, improper rRNA maturation, and the accumulation of a kinetically trapped or mis-assembled ribosomal particle at low temperatures, suggesting defects in ribosome synthesis. Such work emphasizes the important role regulatory RNAs play in the stoichiometric production of ribosomal components for proper ribosome composition and overall organism viability and reinforces the potential of targeting ribosomal protein production and ribosome assembly with novel antimicrobials. Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  17. Increased GAD67 mRNA levels are correlated with in vivo GABA synthesis in the MPTP-treated catecholamine-depleted goldfish brain.

    PubMed

    Hibbert, Benjamin; Fung, Irene; McAuley, Rebecca; Larivière, Katherine; MacNeil, Brian; Bafi-Yeboa, Nana; Livesey, John; Trudeau, Vance

    2004-09-28

    The role of catecholamine neuronal input on GABAergic activity in the hypothalamus, telencephalon, optic tectum, and cerebellum was investigated in early recrudescent female goldfish (Carassius auratus). A new quantitative technique was developed and validated, permitting concomitant quantification and correlational analysis of glutamic acid decarboxylase 65 (GAD65), GAD67, and GAD3 mRNA levels and in vivo GABA synthesis. Catecholamine depletion was achieved by the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 50 microg/g body weight) and dopamine (DA) depletion verified by HPLC. Endogenous GABA levels were increased by intraperitoneal administration of gamma-vinyl GABA (GVG; 300 microg/g body weight), an inhibitor of the GABA catabolic enzyme GABA transaminase. Treatment with MPTP resulted in a greater than twofold increase in GABA synthesis rate in the optic tectum and telencephalon. The increase in GABA synthesis rate was highly correlated with an increase in GAD67, but not GAD65 or GAD3 mRNA levels. These results suggest that catecholaminergic input exerts inhibitory effects on GABA synthesis rates through the modulation of GAD67 in the optic tectum and telencephalon. Together with previously published observations in rodents and primates, it is suggested that catecholaminergic control of GABA synthesis must have evolved more than 200 million years ago, before the emergence of the teleost fishes.

  18. Avian coronavirus isolated from a pigeon sample induced clinical disease, tracheal ciliostasis, and a high humoral response in day-old chicks.

    PubMed

    Martini, Matheus C; Caserta, Leonardo C; Dos Santos, Marcia M A B; Barnabé, Ana C S; Durães-Carvalho, Ricardo; Padilla, Marina A; Simão, Raphael M; Rizotto, Laís S; Simas, Paulo V M; Bastos, Juliana C S; Cardoso, Tereza C; Felippe, Paulo A N; Ferreira, Helena L; Arns, Clarice W

    2018-06-01

    The detection of avian coronaviruses (AvCoV) in wild birds and the emergence of new AvCoV have increased in the past few years. In the present study, the pathogenicity of three AvCoV isolates was investigated in day-old chicks. One AvCoV isolated from a pigeon, which clustered with the Massachusetts vaccine serotype, and two AvCoV isolated from chickens, which grouped with a Brazilian genotype lineage, were used. Clinical signs, gross lesions, histopathological changes, ciliary activity, viral RNA detection, and serology were evaluated during 42 days post infection. All AvCoV isolates induced clinical signs, gross lesions in the trachea, moderate histopathological changes in the respiratory tract, and mild changes in other tissues. AvCoV isolated from the pigeon sample caused complete tracheal ciliostasis over a longer time span. Specific viral RNA was detected in all tissues, but the highest RNA loads were detected in the digestive tract (cloacal swabs and ileum). The highest antibody levels were also detected in the group infected with an isolate from the pigeon. These results confirm the pathogenicity of Brazilian variants, which can cause disease and induce gross lesions and histopathological changes in chickens. Our results suggest that non-Galliformes birds can also play a role in the ecology of AvCoV.

  19. Middle East respiratory syndrome coronavirus: current situation and travel-associated concerns.

    PubMed

    Al-Tawfiq, Jaffar A; Omrani, Ali S; Memish, Ziad A

    2016-06-01

    The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 brought back memories of the occurrence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002. More than 1500 MERS-CoV cases were recorded in 42 months with a case fatality rate (CFR) of 40%. Meanwhile, 8000 cases of SARS-CoV were confirmed in six months with a CFR of 10%. The clinical presentation of MERS-CoV ranges from mild and non-specific presentation to progressive and severe pneumonia. No predictive signs or symptoms exist to differentiate MERS-CoV from community-acquired pneumonia in hospitalized patients. An apparent heterogeneity was observed in transmission. Most MERS-CoV cases were secondary to large outbreaks in healthcare settings. These cases were secondary to community-acquired cases, which may also cause family outbreaks. Travel-associated MERS infection remains low. However, the virus exhibited a clear tendency to cause large outbreaks outside the Arabian Peninsula as exemplified by the outbreak in the Republic of Korea. In this review, we summarize the current knowledge about MERS-CoV and highlight travel-related issues.

  20. Pancreatitis and Systemic Coronavirus Infection in a Ferret (Mustela putorius furo).

    PubMed

    Wills, Sarah E; Beaufrère, Hugues H; Brisson, Brigitte A; Fraser, Russell S; Smith, Dale A

    2018-06-01

    A 1-y-old spayed female ferret (Mustela putorius furo) was referred for additional diagnostic evaluation after physical examination by the referring veterinarian revealed a cranial abdominal mass. The ferret had a 2-wk history of inappetence, weight loss, and lethargy. On presentation, the ferret was thin, and an approximately 3-cm mass was palpable in the cranial abdomen. No other abnormalities were noted. Abdominal ultrasonography confirmed the presence of a soft-tissue structure, with a moderate blood supply and mesenteric lymphadenopathy. Fine-needle aspirates of the mass were nondiagnostic. Exploratory laparotomy revealed multiple nodules and thickened tissues throughout the mesentery, a thickened and nodular pancreas, and a small amount of free abdominal fluid. Histopathology of mesenteric, lymphatic, and pancreatic biopsies revealed suppurative pancreatitis and necrotizing and pyogranulomatous mesenteric steatitis. Positive immunohistochemistry for feline coronavirus confirmed a diagnosis of ferret systemic coronavirus disease (FSCD). The ferret was treated medically with oral prednisolone, improved dramatically, and was still doing well 22 mo after diagnosis. Although FSCD has been reported extensively, this case is noteworthy for the presence of suppurative pancreatitis and the positive long-term outcome after corticosteroid therapy.

  1. Polypyrimidine tract-binding protein influences negative strand RNA synthesis of dengue virus.

    PubMed

    Jiang, Linbin; Yao, Huiling; Duan, Xiaoqun; Lu, Xi; Liu, Yongming

    2009-07-24

    Flavivirus non-structural protein 4A (NS4A) induces membrane rearrangements to form viral replication complex and functions as interferon antagonist. However, other non-structural roles of NS4A protein in relation to virus life-cycle are poorly defined. This study elucidated if dengue virus (DENV) NS4A protein interacts with host proteins and contributes to viral pathogenesis by screening human liver cDNA yeast-two-hybrid library. Our study identified polypyrimidine tract-binding protein (PTB) as a novel interacting partner of DENV NS4A protein. We reported for the first time that PTB influenced DENV production. Gene-silencing studies showed that PTB did not have an effect on DENV entry and DENV RNA translation. Further functional studies revealed that PTB influenced DENV production by modulating negative strand RNA synthesis. This is the first study that enlightens the interaction of DENV NS4A protein with PTB, in addition to demonstrating the novel role of PTB in relation to mosquito-borne flavivirus life-cycle.

  2. Clay catalyzed RNA synthesis under Martian conditions: Application for Mars return samples.

    PubMed

    Joshi, Prakash C; Dubey, Krishna; Aldersley, Michael F; Sausville, Meaghen

    2015-06-26

    Catalysis by montmorillonites clay minerals is regarded as a feasible mechanism for the abiotic production and polymerization of key biomolecules on early Earth. We have investigated a montmorillonite-catalyzed reaction of the 5'-phosphorimidazolide of nucleosides as a model to probe prebiotic synthesis of RNA-type oligomers. Here we show that this model is specific for the generation of RNA oligomers despite deoxy-mononucleotides adsorbing equally well onto the montmorillonite catalytic surfaces. Optimum catalytic activity was observed over a range of pH (6-9) and salinity (1 ± 0.2 M NaCl). When the weathering steps of early Earth that generated catalytic montmorillonite were modified to meet Martian soil conditions, the catalytic activity remained intact without altering the surface layer charge. Additionally, the formation of oligomers up to tetramer was detected using as little as 0.1 mg of Na⁺-montmorillonite, suggesting that the catalytic activity of a Martian clay return sample can be investigated with sub-milligram scale samples. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Human coronavirus EMC does not require the SARS-coronavirus receptor and maintains broad replicative capability in mammalian cell lines.

    PubMed

    Müller, Marcel A; Raj, V Stalin; Muth, Doreen; Meyer, Benjamin; Kallies, Stephan; Smits, Saskia L; Wollny, Robert; Bestebroer, Theo M; Specht, Sabine; Suliman, Tasnim; Zimmermann, Katrin; Binger, Tabea; Eckerle, Isabella; Tschapka, Marco; Zaki, Ali M; Osterhaus, Albert D M E; Fouchier, Ron A M; Haagmans, Bart L; Drosten, Christian

    2012-12-11

    A new human coronavirus (hCoV-EMC) has emerged very recently in the Middle East. The clinical presentation resembled that of the severe acute respiratory syndrome (SARS) as encountered during the epidemic in 2002/2003. In both cases, acute renal failure was observed in humans. HCoV-EMC is a member of the same virus genus as SARS-CoV but constitutes a sister species. Here we investigated whether it might utilize angiotensin-converting enzyme 2 (ACE2), the SARS-CoV receptor. Knowledge of the receptor is highly critical because the restriction of the SARS receptor to deep compartments of the human respiratory tract limited the spread of SARS. In baby hamster kidney (BHK) cells, lentiviral transduction of human ACE2 (hACE2) conferred permissiveness and replication for SARS-CoV but not for hCoV-EMC. Monkey and human kidney cells (LLC-MK2, Vero, and 769-P) and swine kidney cells were permissive for both viruses, but only SARS-CoV infection could be blocked by anti-hACE2 antibody and could be neutralized by preincubation of virus with soluble ACE2. Our data show that ACE2 is neither necessary nor sufficient for hCoV-EMC replication. Moreover, hCoV-EMC, but not SARS-CoV, replicated in cell lines from Rousettus, Rhinolophus, Pipistrellus, Myotis, and Carollia bats, representing four major chiropteran families from both suborders. As human CoV normally cannot replicate in bat cells from different families, this suggests that hCoV-EMC might use a receptor molecule that is conserved in bats, pigs, and humans, implicating a low barrier against cross-host transmission. IMPORTANCE A new human coronavirus (hCoV) emerged recently in the Middle East. The disease resembled SARS (severe acute respiratory syndrome), causing a fatal epidemic in 2002/2003. Coronaviruses have a reservoir in bats and because this novel virus is related to SARS-CoV, we investigated whether it might replicate in bat cells and use the same receptor (angiotensin-converting enzyme 2 [ACE2]). This knowledge is

  4. Murine Coronavirus Ubiquitin-Like Domain Is Important for Papain-Like Protease Stability and Viral Pathogenesis

    PubMed Central

    Mielech, Anna M.; Deng, Xufang; Chen, Yafang; Kindler, Eveline; Wheeler, Dorthea L.; Mesecar, Andrew D.; Thiel, Volker; Perlman, Stanley

    2015-01-01

    ABSTRACT Ubiquitin-like domains (Ubls) now are recognized as common elements adjacent to viral and cellular proteases; however, their function is unclear. Structural studies of the papain-like protease (PLP) domains of coronaviruses (CoVs) revealed an adjacent Ubl domain in severe acute respiratory syndrome CoV, Middle East respiratory syndrome CoV, and the murine CoV, mouse hepatitis virus (MHV). Here, we tested the effect of altering the Ubl adjacent to PLP2 of MHV on enzyme activity, viral replication, and pathogenesis. Using deletion and substitution approaches, we identified sites within the Ubl domain, residues 785 to 787 of nonstructural protein 3, which negatively affect protease activity, and valine residues 785 and 787, which negatively affect deubiquitinating activity. Using reverse genetics, we engineered Ubl mutant viruses and found that AM2 (V787S) and AM3 (V785S) viruses replicate efficiently at 37°C but generate smaller plaques than wild-type (WT) virus, and AM2 is defective for replication at higher temperatures. To evaluate the effect of the mutation on protease activity, we purified WT and Ubl mutant PLP2 and found that the proteases exhibit similar specific activities at 25°C. However, the thermal stability of the Ubl mutant PLP2 was significantly reduced at 30°C, thereby reducing the total enzymatic activity. To determine if the destabilizing mutation affects viral pathogenesis, we infected C57BL/6 mice with WT or AM2 virus and found that the mutant virus is highly attenuated, yet it replicates sufficiently to elicit protective immunity. These studies revealed that modulating the Ubl domain adjacent to the PLP reduces protease stability and viral pathogenesis, revealing a novel approach to coronavirus attenuation. IMPORTANCE Introducing mutations into a protein or virus can have either direct or indirect effects on function. We asked if changes in the Ubl domain, a conserved domain adjacent to the coronavirus papain-like protease, altered

  5. relA-dependent RNA polymerase activity in Escherichia coli.

    PubMed Central

    Ryals, J; Bremer, H

    1982-01-01

    Parameters relating to RNA synthesis were measured after a temperature shift from 30 to 42 degrees C, in a relA+ and relA- isogenic pair of Escherichia coli strains containing a temperature-sensitive valyl tRNA synthetase. The following results were obtained: (i) the rRNA chain growth rate increased 2-fold in both strains; (ii) newly synthesized rRNA became unstable in both strains; (iii) the stable RNA gene activity (rRNA and tRNA, measured as stable RNA synthesis rate relative to the total instantaneous rate of RNA synthesis) decreased 1.7-fold in the relA+ strain and increased 1.9-fold in the relA mutant; and (iv) the RNA polymerase activity (measured by the percentage of total RNA polymerase enzyme active in transcription an any instant) decreased from 20 to 3.6% in the relA+ strain and remained unchanged (or increased at most to 22%) in the relA mutant. It is suggested that both rRNA gene activity and the RNA polymerase activity depend on the intracellular concentration of guanosine tetraphosphate, whereas the altered chain elongation rate and stability of rRNA are temperature or amino acid starvation effects, respectively, without involvement of relA function. PMID:6174501

  6. Clinical, hematological, and biochemical findings in puppies with coronavirus and parvovirus enteritis

    PubMed Central

    Castro, Tatiana X.; Cubel Garcia, Rita de Cássia N.; Gonçalves, Luciana P. S.; Costa, Erika M.; Marcello, Gracy C.G.; Labarthe, Norma V.; Mendes-de-Almeida, Flavya

    2013-01-01

    The clinical and laboratory findings in puppies naturally infected with canine coronavirus (CCoV) and/or canine parvovirus (CPV) were compared with findings in uninfected puppies. Lymphopenia was the only parameter related to CCoV infection that was statistically significant; vomiting, anorexia, lethargy, hemorrhagic fluid diarrhea, leukopenia, lymphopenia, thrombocytopenia, hypoglycemia, and hypoproteinemia were correlated with CPV infection. PMID:24155496

  7. Acute Middle East Respiratory Syndrome Coronavirus Infection in Livestock Dromedaries, Dubai, 2014

    PubMed Central

    Corman, Victor M.; Wong, Emily Y.M.; Tsang, Alan K.L.; Muth, Doreen; Lau, Susanna K. P.; Khazanehdari, Kamal; Zirkel, Florian; Ali, Mansoor; Nagy, Peter; Juhasz, Jutka; Wernery, Renate; Joseph, Sunitha; Syriac, Ginu; Elizabeth, Shyna K.; Patteril, Nissy Annie Georgy; Woo, Patrick C. Y.; Drosten, Christian

    2015-01-01

    Camels carry Middle East respiratory syndrome coronavirus, but little is known about infection age or prevalence. We studied >800 dromedaries of all ages and 15 mother–calf pairs. This syndrome constitutes an acute, epidemic, and time-limited infection in camels <4 years of age, particularly calves. Delayed social separation of calves might reduce human infection risk. PMID:25989145

  8. Viral metagenomics, protein structure, and reverse genetics: Key strategies for investigating coronaviruses.

    PubMed

    Johnson, Bryan A; Graham, Rachel L; Menachery, Vineet D

    2018-04-01

    Viral metagenomics, modeling of protein structure, and manipulation of viral genetics are key approaches that have laid the foundations of our understanding of coronavirus biology. In this review, we discuss the major advances each method has provided and discuss how future studies should leverage these strategies synergistically to answer novel questions. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Hypoxia induces IGFBP3 in esophageal squamous cancer cells through HIF-1α-mediated mRNA transcription and continuous protein synthesis

    PubMed Central

    Natsuizaka, Mitsuteru; Naganuma, Seiji; Kagawa, Shingo; Ohashi, Shinya; Ahmadi, Azal; Subramanian, Harry; Chang, Sanders; Nakagawa, Kei J.; Ji, Xinjun; Liebhaber, Stephen A.; Klein-Szanto, Andres J.; Nakagawa, Hiroshi

    2012-01-01

    Insulin-like growth factor binding protein (IGFBP)-3 regulates cell proliferation and apoptosis in esophageal squamous cell carcinoma (ESCC) cells. We have investigated how the hypoxic tumor microenvironment in ESCC fosters the induction of IGFBP3. RNA interference experiments revealed that hypoxia-inducible factor (HIF)-1α, but not HIF-2α, regulates IGFBP3 mRNA induction. By chromatin immunoprecipitation and transfection assays, HIF-1α was found to transactivate IGFBP3 through a novel hypoxia responsive element (HRE) located at 57 kb upstream from the transcription start site. Metabolic labeling experiments demonstrated hypoxia-mediated inhibition of global protein synthesis. 7-Methyl GTP-cap binding assays suggested that hypoxia suppresses cap-dependent translation. Experiments using pharmacological inhibitors for mammalian target of rapamycin (mTOR) suggested that a relatively weak mTOR activity may be sufficient for cap-dependent translation of IGFBP3 under hypoxic conditions. Bicistronic RNA reporter transfection assays did not validate the possibility of an internal ribosome entry site as a potential mechanism for cap-independent translation for IGFBP3 mRNA. Finally, IGFBP3 mRNA was found enriched to the polysomes. In aggregate, our study establishes IGFBP3 as a direct HIF-1α target gene and that polysome enrichment of IGFBP3 mRNA may permit continuous translation under hypoxic conditions.—Natsuizaka, M., Naganuma, S., Kagawa, S., Ohashi, S., Ahmadi, A., Subramanian, H., Chang, S., Nakagawa, K. J., Ji, X., Liebhaber, S. A., Klein-Szanto, A. J., Nakagawa, H. Hypoxia induces IGFBP3 in esophageal squamous cancer cells through HIF-1α-mediated mRNA transcription and continuous protein synthesis. PMID:22415309

  10. Overview of methods in RNA nanotechnology: synthesis, purification, and characterization of RNA nanoparticles.

    PubMed

    Haque, Farzin; Guo, Peixuan

    2015-01-01

    RNA nanotechnology encompasses the use of RNA as a construction material to build homogeneous nanostructures by bottom-up self-assembly with defined size, structure, and stoichiometry; this pioneering concept demonstrated in 1998 (Guo et al., Molecular Cell 2:149-155, 1998; featured in Cell) has emerged as a new field that also involves materials engineering and synthetic structural biology (Guo, Nature Nanotechnology 5:833-842, 2010). The field of RNA nanotechnology has skyrocketed over the last few years, as evidenced by the burst of publications in prominent journals on RNA nanostructures and their applications in nanomedicine and nanotechnology. Rapid advances in RNA chemistry, RNA biophysics, and RNA biology have created new opportunities for translating basic science into clinical practice. RNA nanotechnology holds considerable promise in this regard. Increased evidence also suggests that substantial part of the 98.5 % of human genome (Lander et al. Nature 409:860-921, 2001) that used to be called "junk DNA" actually codes for noncoding RNA. As we understand more on how RNA structures are related to function, we can fabricate synthetic RNA nanoparticles for the diagnosis and treatment of diseases. This chapter provides a brief overview of the field regarding the design, construction, purification, and characterization of RNA nanoparticles for diverse applications in nanotechnology and nanomedicince.

  11. Nonenzymatic synthesis of RNA and DNA oligomers on hexitol nucleic acid templates: the importance of the A structure

    NASA Technical Reports Server (NTRS)

    Kozlov, I. A.; Politis, P. K.; Van Aerschot, A.; Busson, R.; Herdewijn, P.; Orgel, L. E.; Bada, J. L. (Principal Investigator); Dolan, M. (Principal Investigator)

    1999-01-01

    Hexitol nucleic acid (HNA) is an analogue of DNA containing the standard nucleoside bases, but with a phosphorylated 1,5-anhydrohexitol backbone. HNA oligomers form duplexes having the nucleic acid A structure with complementary DNA or RNA oligomers. The HNA decacytidylate oligomer is an efficient template for the oligomerization of the 5'-phosphoroimidazolides of guanosine or deoxyguanosine. Comparison of the oligomerization efficiencies on HNA, RNA, and DNA decacytidylate templates under various conditions suggests strongly that only nucleic acid double helices with the A structure support efficient template-directed synthesis when 5'-phosphoroimidazolides of nucleosides are used as substrates.

  12. Memory T cell responses targeting the SARS coronavirus persist up to 11 years post-infection.

    PubMed

    Ng, Oi-Wing; Chia, Adeline; Tan, Anthony T; Jadi, Ramesh S; Leong, Hoe Nam; Bertoletti, Antonio; Tan, Yee-Joo

    2016-04-12

    Severe acute respiratory syndrome (SARS) is a highly contagious infectious disease which first emerged in late 2002, caused by a then novel human coronavirus, SARS coronavirus (SARS-CoV). The virus is believed to have originated from bats and transmitted to human through intermediate animals such as civet cats. The re-emergence of SARS-CoV remains a valid concern due to the continual persistence of zoonotic SARS-CoVs and SARS-like CoVs (SL-CoVs) in bat reservoirs. In this study, the screening for the presence of SARS-specific T cells in a cohort of three SARS-recovered individuals at 9 and 11 years post-infection was carried out, and all memory T cell responses detected target the SARS-CoV structural proteins. Two CD8(+) T cell responses targeting the SARS-CoV membrane (M) and nucleocapsid (N) proteins were characterized by determining their HLA restriction and minimal T cell epitope regions. Furthermore, these responses were found to persist up to 11 years post-infection. An absence of cross-reactivity of these CD8(+) T cell responses against the newly-emerged Middle East respiratory syndrome coronavirus (MERS-CoV) was also demonstrated. The knowledge of the persistence of SARS-specific celullar immunity targeting the viral structural proteins in SARS-recovered individuals is important in the design and development of SARS vaccines, which are currently unavailable. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Targeting of Arenavirus RNA Synthesis by a Carboxamide-Derivatized Aromatic Disulfide with Virucidal Activity

    PubMed Central

    Sepúlveda, Claudia S.; García, Cybele C.; Levingston Macleod, Jesica M.

    2013-01-01

    Several arenaviruses can cause severe hemorrhagic fever (HF) in humans, representing a public health threat in endemic areas of Africa and South America. The present study characterizes the potent virucidal activity of the carboxamide-derivatized aromatic disulfide NSC4492, an antiretroviral zinc finger-reactive compound, against Junín virus (JUNV), the causative agent of Argentine HF. The compound was able to inactivate JUNV in a time and temperature-dependent manner, producing more than 99 % reduction in virus titer upon incubation with virions at 37°C for 90 min. The ability of NSC4492-treated JUNV to go through different steps of the multiplication cycle was then evaluated. Inactivated virions were able to bind and enter into the host cell with similar efficiency as control infectious particles. In contrast, treatment with NSC4492 impaired the capacity of JUNV to drive viral RNA synthesis, as measured by quantitative RT-PCR, and blocked viral protein expression, as determined by indirect immunofluorescence. These results suggest that the disulfide NSC4492 targets on the arenavirus replication complex leading to impairment in viral RNA synthesis. Additionally, analysis of VLP produced in NSC4492-treated cells expressing JUNV matrix Z protein revealed that the compound may interact with Z resulting in an altered aggregation behavior of this protein, but without affecting its intrinsic self-budding properties. The potential perspectives of NSC4492 as an inactivating vaccinal compound for pathogenic arenaviruses are discussed. PMID:24278404

  14. The molecular variability analysis of the RNA 3 of fifteen isolates of Prunus necrotic ringspot virus sheds light on the minimal requirements for the synthesis of its subgenomic RNA.

    PubMed

    Aparicio, Frederic; Pallás, Vicente

    2002-01-01

    The nucleotide sequences of the RNA 3 of fifteen isolates of Prunus necrotic ringspot virus (PNRSV) varying in the symptomatology they cause in six different Prunus spp. were determined. Analysis of the molecular variability has allowed, in addition to study the phylogenetic relationships among them, to evaluate the minimal requirements for the synthesis of the subgenomic RNA in Ilarvirus genus and their comparison to other members of the Bromoviridae family. Computer assisted comparisons led recently to Jaspars (Virus Genes 17, 233-242, 1998) to propose that a hairpin structure in viral minus strand RNA is required for subgenomic promoter activity of viruses from at least two, and possibly all five, genera in the family of Bromoviridae. For PNRSV and Apple mosaic virus two stable hairpins were proposed whereas for the rest of Ilarviruses and the other four genera of the Bromoviridae family only one stable hairpin was predicted. Comparative analysis of this region among the fifteen PNRSV isolates characterized in this study revealed that two of them showed a 12-nt deletion that led to the disappearance of the most proximal hairpin to the initiation site. Interestingly, the only hairpin found in these two isolates is very similar in primary and secondary structure to the one previously shown in Brome mosaic virus to be required for the synthesis of the subgenomic RNA. In this hairpin, the molecular diversity was concentrated mostly at the loop whereas compensatory mutations were observed at the base of the stem strongly suggesting its functional relevance. The evolutionary implications of these observations are discussed.

  15. De Novo mRNA Synthesis Is Required for Both Consolidation and Reconsolidation of Fear Memories in the Amygdala

    ERIC Educational Resources Information Center

    Duvarci, Sevil; Nader, Karim; LeDoux, Joseph E.

    2008-01-01

    Memory consolidation is the process by which newly learned information is stabilized into long-term memory (LTM). Considerable evidence indicates that retrieval of a consolidated memory returns it to a labile state that requires it to be restabilized. Consolidation of new fear memories has been shown to require de novo RNA and protein synthesis in…

  16. Cytometry of DNA Replication and RNA Synthesis: Historical Perspective and Recent Advances Based on “Click Chemistry”

    PubMed Central

    Darzynkiewicz, Zbigniew; Traganos, Frank; Zhao, Hong; Halicka, H. Dorota; Li, Jiangwei

    2011-01-01

    This review covers progress in the development of cytometric methodologies designed to assess DNA replication and RNA synthesis. The early approaches utilizing autoradiography to detect incorporation of 3H- or 14C-labeled thymidine were able to identify the four fundamental phases of the cell cycle G1, S, G2, and M, and by analysis of the fraction of labeled mitosis (FLM), to precisely define the kinetics of cell progression through these phases. Analysis of 3H-uridine incorporation and RNA content provided the means to distinguish quiescent G0 from cycling G1 cells. Subsequent progress in analysis of DNA replication was based on the use of BrdU as a DNA precursor and its detection by the quenching of the fluorescence intensity of DNA-bound fluorochromes such as Hoechst 33358 or acridine orange as measured by flow cytometry. Several variants of this methodology have been designed and used in studies to detect anticancer drug-induced perturbations of cell cycle kinetics. The next phase of method development, which was particularly useful in studies of the cell cycle in vivo, including clinical applications, relied on immunocytochemical detection of incorporated halogenated DNA or RNA precursors. This approach however was hampered by the need for DNA denaturation, which made it difficult to concurrently detect other cell constituents for multiparametric analysis. The recently introduced “click chemistry” approach has no such limitation and is the method of choice for analysis of DNA replication and RNA synthesis. This method is based on the use of 5-ethynyl-2′deoxyuridine (EdU) as a DNA precursor or 5-ethynyluridine (EU) as an RNA precursor and their detection with fluorochrome-tagged azides utilizing a copper (I) catalyzed [3+2] cycloaddition. Several examples are presented that illustrate incorporation of EdU or EU in cells subjected to DNA damage detected as histone H2AX phosphorylation that have been analyzed by flow or laser scanning cytometry. PMID

  17. Base modifications affecting RNA polymerase and reverse transcriptase fidelity.

    PubMed

    Potapov, Vladimir; Fu, Xiaoqing; Dai, Nan; Corrêa, Ivan R; Tanner, Nathan A; Ong, Jennifer L

    2018-06-20

    Ribonucleic acid (RNA) is capable of hosting a variety of chemically diverse modifications, in both naturally-occurring post-transcriptional modifications and artificial chemical modifications used to expand the functionality of RNA. However, few studies have addressed how base modifications affect RNA polymerase and reverse transcriptase activity and fidelity. Here, we describe the fidelity of RNA synthesis and reverse transcription of modified ribonucleotides using an assay based on Pacific Biosciences Single Molecule Real-Time sequencing. Several modified bases, including methylated (m6A, m5C and m5U), hydroxymethylated (hm5U) and isomeric bases (pseudouridine), were examined. By comparing each modified base to the equivalent unmodified RNA base, we can determine how the modification affected cumulative RNA polymerase and reverse transcriptase fidelity. 5-hydroxymethyluridine and N6-methyladenosine both increased the combined error rate of T7 RNA polymerase and reverse transcriptases, while pseudouridine specifically increased the error rate of RNA synthesis by T7 RNA polymerase. In addition, we examined the frequency, mutational spectrum and sequence context of reverse transcription errors on DNA templates from an analysis of second strand DNA synthesis.

  18. RNA versatility governs tRNA function: Why tRNA flexibility is essential beyond the translation cycle.

    PubMed

    Kuhn, Claus-D

    2016-05-01

    tRNAs undergo multiple conformational changes during the translation cycle that are required for tRNA translocation and proper communication between the ribosome and translation factors. Recent structural data on how destabilized tRNAs utilize the CCA-adding enzyme to proofread themselves put a spotlight on tRNA flexibility beyond the translation cycle. In analogy to tRNA surveillance, this review finds that other processes also exploit versatile tRNA folding to achieve, amongst others, specific aminoacylation, translational regulation by riboswitches or a block of bacterial translation. tRNA flexibility is thereby not restricted to the hinges utilized during translation. In contrast, the flexibility of tRNA is distributed all over its L-shape and is actively exploited by the tRNA-interacting partners to discriminate one tRNA from another. Since the majority of tRNA modifications also modulate tRNA flexibility it seems that cells devote enormous resources to tightly sense and regulate tRNA structure. This is likely required for error-free protein synthesis. © 2016 WILEY Periodicals, Inc.

  19. Rewiring the severe acute respiratory syndrome coronavirus (SARS-CoV) transcription circuit: Engineering a recombination-resistant genome

    NASA Astrophysics Data System (ADS)

    Yount, Boyd; Roberts, Rhonda S.; Lindesmith, Lisa; Baric, Ralph S.

    2006-08-01

    Live virus vaccines provide significant protection against many detrimental human and animal diseases, but reversion to virulence by mutation and recombination has reduced appeal. Using severe acute respiratory syndrome coronavirus as a model, we engineered a different transcription regulatory circuit and isolated recombinant viruses. The transcription network allowed for efficient expression of the viral transcripts and proteins, and the recombinant viruses replicated to WT levels. Recombinant genomes were then constructed that contained mixtures of the WT and mutant regulatory circuits, reflecting recombinant viruses that might occur in nature. Although viable viruses could readily be isolated from WT and recombinant genomes containing homogeneous transcription circuits, chimeras that contained mixed regulatory networks were invariantly lethal, because viable chimeric viruses were not isolated. Mechanistically, mixed regulatory circuits promoted inefficient subgenomic transcription from inappropriate start sites, resulting in truncated ORFs and effectively minimize viral structural protein expression. Engineering regulatory transcription circuits of intercommunicating alleles successfully introduces genetic traps into a viral genome that are lethal in RNA recombinant progeny viruses. regulation | systems biology | vaccine design

  20. Development of chemical inhibitors of the SARS coronavirus: viral helicase as a potential target.

    PubMed

    Keum, Young-Sam; Jeong, Yong-Joo

    2012-11-15

    Severe acute respiratory syndrome (SARS) was the first pandemic in the 21st century to claim more than 700 lives worldwide. However, effective anti-SARS vaccines or medications are currently unavailable despite being desperately needed to adequately prepare for a possible SARS outbreak. SARS is caused by a novel coronavirus, and one of its components, a viral helicase, is emerging as a promising target for the development of chemical SARS inhibitors. In the following review, we describe the characterization, family classification, and kinetic movement mechanisms of the SARS coronavirus (SCV) helicase-nsP13. We also discuss the recent progress in the identification of novel chemical inhibitors of nsP13 in the context of our recent discovery of the strong inhibition of the SARS helicase by natural flavonoids, myricetin and scutellarein. These compounds will serve as important resources for the future development of anti-SARS medications. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Mlc Is a Transcriptional Activator with a Key Role in Integrating Cyclic AMP Receptor Protein and Integration Host Factor Regulation of Leukotoxin RNA Synthesis in Aggregatibacter actinomycetemcomitans

    PubMed Central

    Childress, Catherine; Feuerbacher, Leigh A.; Phillips, Linda; Burgum, Alex

    2013-01-01

    Aggregatibacter actinomycetemcomitans, a periodontal pathogen, synthesizes leukotoxin (LtxA), a protein that helps the bacterium evade the host immune response. Transcription of the ltxA operon is induced during anaerobic growth. The cyclic AMP (cAMP) receptor protein (CRP) indirectly increases ltxA expression, but the intermediary regulator is unknown. Integration host factor (IHF) binds to and represses the leukotoxin promoter, but neither CRP nor IHF is responsible for the anaerobic induction of ltxA RNA synthesis. Thus, we have undertaken studies to identify other regulators of leukotoxin transcription and to demonstrate how these proteins work together to modulate leukotoxin synthesis. First, analyses of ltxA RNA expression from defined leukotoxin promoter mutations in the chromosome identify positions −69 to −35 as the key control region and indicate that an activator protein modulates leukotoxin transcription. We show that Mlc, which is a repressor in Escherichia coli, functions as a direct transcriptional activator in A. actinomycetemcomitans; an mlc deletion mutant reduces leukotoxin RNA synthesis, and recombinant Mlc protein binds specifically at the −68 to −40 region of the leukotoxin promoter. Furthermore, we show that CRP activates ltxA expression indirectly by increasing the levels of Mlc. Analyses of Δmlc, Δihf, and Δihf Δmlc strains demonstrate that Mlc can increase RNA polymerase (RNAP) activity directly and that IHF represses ltxA RNA synthesis mainly by blocking Mlc binding. Finally, a Δihf Δmlc mutant still induces ltxA during anaerobic growth, indicating that there are additional factors involved in leukotoxin transcriptional regulation. A model for the coordinated regulation of leukotoxin transcription is presented. PMID:23475968

  2. mTOR-dependent activation of the transcription factor TIF-IA links rRNA synthesis to nutrient availability.

    PubMed

    Mayer, Christine; Zhao, Jian; Yuan, Xuejun; Grummt, Ingrid

    2004-02-15

    In cycling cells, transcription of ribosomal RNA genes by RNA polymerase I (Pol I) is tightly coordinated with cell growth. Here, we show that the mammalian target of rapamycin (mTOR) regulates Pol I transcription by modulating the activity of TIF-IA, a regulatory factor that senses nutrient and growth-factor availability. Inhibition of mTOR signaling by rapamycin inactivates TIF-IA and impairs transcription-initiation complex formation. Moreover, rapamycin treatment leads to translocation of TIF-IA into the cytoplasm. Rapamycin-mediated inactivation of TIF-IA is caused by hypophosphorylation of Se 44 (S44) and hyperphosphorylation of Se 199 (S199). Phosphorylation at these sites affects TIF-IA activity in opposite ways, for example, phosphorylation of S44 activates and S199 inactivates TIF-IA. The results identify a new target formTOR-signaling pathways and elucidate the molecular mechanism underlying mTOR-dependent regulation of RNA synthesis.

  3. Protection from SARS coronavirus conferred by live measles vaccine expressing the spike glycoprotein.

    PubMed

    Escriou, Nicolas; Callendret, Benoît; Lorin, Valérie; Combredet, Chantal; Marianneau, Philippe; Février, Michèle; Tangy, Frédéric

    2014-03-01

    The recent identification of a novel human coronavirus responsible of a SARS-like illness in the Middle-East a decade after the SARS pandemic, demonstrates that reemergence of a SARS-like coronavirus from an animal reservoir remains a credible threat. Because SARS is contracted by aerosolized contamination of the respiratory tract, a vaccine inducing mucosal long-term protection would be an asset to control new epidemics. To this aim, we generated live attenuated recombinant measles vaccine (MV) candidates expressing either the membrane-anchored SARS-CoV spike (S) protein or its secreted soluble ectodomain (Ssol). In mice susceptible to measles virus, recombinant MV expressing the anchored full-length S induced the highest titers of neutralizing antibodies and fully protected immunized animals from intranasal infectious challenge with SARS-CoV. As compared to immunization with adjuvanted recombinant Ssol protein, recombinant MV induced stronger and Th1-biased responses, a hallmark of live attenuated viruses and a highly desirable feature for an antiviral vaccine. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Immune evasion of porcine enteric coronaviruses and viral modulation of antiviral innate signaling.

    PubMed

    Zhang, Qingzhan; Yoo, Dongwan

    2016-12-02

    Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) are emerged and reemerging viruses in pigs, and together with transmissible gastroenteritis virus (TGEV), pose significant economic concerns to the swine industry. These viruses infect epithelial cells of the small intestine and cause watery diarrhea, dehydration, and a high mortality in neonatal piglets. Type I interferons (IFN-α/β) are major antiviral cytokines forming host innate immunity, and in turn, these enteric coronaviruses have evolved to modulate the host innate immune signaling during infection. Accumulating evidence however suggests that IFN induction and signaling in the intestinal epithelial cells differ from other epithelial cells, largely due to distinct features of the gut epithelial mucosal surface and commensal microflora, and it appears that type III interferon (IFN-λ) plays a key role to maintain the antiviral state in the gut. This review describes the recent understanding on the immune evasion strategies of porcine enteric coronaviruses and the role of different types of IFNs for intestinal antiviral innate immunity. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism.

    PubMed

    Francis, Andrew J; Resendiz, Marino J E

    2017-07-28

    Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5'-[CUA CGG AAU CAU]-3' containing zero, one, or two modifications located at the C2'-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2'-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in

  6. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Versteeg, Gijs A.; Bredenbeek, Peter J.; Worm, Sjoerd H.E. van den

    Many viruses encode antagonists to prevent interferon (IFN) induction. Infection of fibroblasts with the murine hepatitis coronavirus (MHV) and SARS-coronavirus (SARS-CoV) did not result in nuclear translocation of interferon-regulatory factor 3 (IRF3), a key transcription factor involved in IFN induction, and induction of IFN mRNA transcription. Furthermore, MHV and SARS-CoV infection could not prevent IFN induction by poly (I:C) or Sendai virus, suggesting that these CoVs do not inactivate IRF3-mediated transcription regulation, but apparently prevent detection of replicative RNA by cellular sensory molecules. Our data indicate that shielding of viral RNA to host cell sensors might be the main generalmore » mechanism for coronaviruses to prevent IFN induction.« less

  7. Induction of human spermine oxidase SMO(PAOh1) is regulated at the levels of new mRNA synthesis, mRNA stabilization and newly synthesized protein

    PubMed Central

    2004-01-01

    The oxidation of polyamines induced by antitumour polyamine analogues has been associated with tumour response to specific agents. The human spermine oxidase, SMO(PAOh1), is one enzyme that may play a direct role in the cellular response to the antitumour polyamine analogues. In the present study, the induction of SMO(PAOh1) enzyme activity by CPENSpm [N1-ethyl-N11-(cyclopropyl)methyl-4,8,diazaundecane] is demonstrated to be a result of newly synthesized mRNA and protein. Inhibition of new RNA synthesis by actinomycin D inhibits both the appearance of SMO(PAOh1) mRNA and enzyme activity. Similarly, inhibition of newly synthesized protein with cycloheximide prevents analogue-induced enzyme activity. Half-life determinations indicate that stabilization of SMO(PAOh1) protein does not play a significant role in analogue-induced activity. However, half-life experiments using actinomycin D indicate that CPENSpm treatment not only increases mRNA expression, but also leads to a significant increase in mRNA half-life (17.1 and 8.8 h for CPENSpm-treated cells and control respectively). Using reporter constructs encompassing the SMO(PAOh1) promoter region, a 30–90% increase in transcription is observed after exposure to CPENSpm. The present results are consistent with the hypothesis that analogue-induced expression of SMO(PAOh1) is a result of increased transcription and stabilization of SMO(PAOh1) mRNA, leading to increased protein production and enzyme activity. These data indicate that the major level of control of SMO(PAOh1) expression in response to polyamine analogues exposure is at the level of mRNA. PMID:15496143

  8. Control of rRNA and tRNA syntheses in Escherichia coli by guanosine tetraphosphate.

    PubMed Central

    Ryals, J; Little, R; Bremer, H

    1982-01-01

    The expression of stable RNA (rRNA and tRNA) genes and the concentration of guanosine tetraphosphate (ppGpp) were measured in an isogenic pair of relA+ and relA derivatives of Escherichia coli B/r. The cells were either growing exponentially at different rates or subject to amino acid starvation when they were measured. The specific stable RNA gene activity (rs/rt, the rate of rRNA and tRNA synthesis relative to the total instantaneous rate of RNA synthesis) was found to decrease from 1.0 at a ppGpp concentration of 0 (extrapolated value) to 0.24 at saturating concentrations of ppGpp (above 100 pmoles per optical density at 460 nm unit of cell mass). The same relationship between the rs/rt ratio and ppGpp concentration was obtained independent of the physiological state of the bacteria (i.e., independent of the growth rate or of amino acid starvation) and independent of the relA allele. It can be concluded that ppGpp is an effector for stable RNA gene control and that stable RNA genes are not controlled by factors other than the ppGpp-mediated system. The results were shown to be qualitatively and quantitatively consistent with data on in vitro rRNA gene control by ppGpp, and they were interpreted in the light of reported ideas derived from those in vitro experiments. PMID:6179924

  9. A Real-Time PCR Assay for Bat SARS-Like Coronavirus Detection and Its Application to Italian Greater Horseshoe Bat Faecal Sample Surveys

    PubMed Central

    Balboni, Andrea; Gallina, Laura; Palladini, Alessandra; Prosperi, Santino; Battilani, Mara

    2012-01-01

    Bats are source of coronaviruses closely related to the severe acute respiratory syndrome (SARS) virus. Numerous studies have been carried out to identify new bat viruses related to SARS-coronavirus (bat-SARS-like CoVs) using a reverse-transcribed-polymerase chain reaction assay. However, a qualitative PCR could underestimate the prevalence of infection, affecting the epidemiological evaluation of bats in viral ecology. In this work an SYBR Green-real time PCR assay was developed for diagnosing infection with SARS-related coronaviruses from bat guano and was applied as screening tool in a survey carried out on 45 greater horseshoe bats (Rhinolophus ferrumequinum) sampled in Italy in 2009. The assay showed high sensitivity and reproducibility. Its application on bats screening resulted in a prevalence of 42%. This method could be suitable as screening tool in epidemiological surveys about the presence of bat-SARS-like CoVs, consequently to obtain a more realistic scenario of the viral prevalence in the population. PMID:22654650

  10. Detection of Severe Acute Respiratory Syndrome-Like, Middle East Respiratory Syndrome-Like Bat Coronaviruses and Group H Rotavirus in Faeces of Korean Bats.

    PubMed

    Kim, H K; Yoon, S-W; Kim, D-J; Koo, B-S; Noh, J Y; Kim, J H; Choi, Y G; Na, W; Chang, K-T; Song, D; Jeong, D G

    2016-08-01

    Bat species around the world have recently been recognized as major reservoirs of several zoonotic viruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), Nipah virus and Hendra virus. In this study, consensus primer-based reverse transcriptase polymerase chain reactions (RT-PCRs) and high-throughput sequencing were performed to investigate viruses in bat faecal samples collected at 11 natural bat habitat sites from July to December 2015 in Korea. Diverse coronaviruses were first detected in Korean bat faeces, including alphacoronaviruses, SARS-CoV-like and MERS-CoV-like betacoronaviruses. In addition, we identified a novel bat rotavirus belonging to group H rotavirus which has only been described in human and pigs until now. Therefore, our results suggest the need for continuing surveillance and additional virological studies in domestic bat. © 2016 Blackwell Verlag GmbH.

  11. mTOR-dependent activation of the transcription factor TIF-IA links rRNA synthesis to nutrient availability

    PubMed Central

    Mayer, Christine; Zhao, Jian; Yuan, Xuejun; Grummt, Ingrid

    2004-01-01

    In cycling cells, transcription of ribosomal RNA genes by RNA polymerase I (Pol I) is tightly coordinated with cell growth. Here, we show that the mammalian target of rapamycin (mTOR) regulates Pol I transcription by modulating the activity of TIF-IA, a regulatory factor that senses nutrient and growth-factor availability. Inhibition of mTOR signaling by rapamycin inactivates TIF-IA and impairs transcription-initiation complex formation. Moreover, rapamycin treatment leads to translocation of TIF-IA into the cytoplasm. Rapamycin-mediated inactivation of TIF-IA is caused by hypophosphorylation of Ser 44 (S44) and hyperphosphorylation of Ser 199 (S199). Phosphorylation at these sites affects TIF-IA activity in opposite ways, for example, phosphorylation of S44 activates and S199 inactivates TIF-IA. The results identify a new target for mTOR-signaling pathways and elucidate the molecular mechanism underlying mTOR-dependent regulation of rRNA synthesis. PMID:15004009

  12. Control of rRNA transcription in Escherichia coli.

    PubMed Central

    Condon, C; Squires, C; Squires, C L

    1995-01-01

    The control of rRNA synthesis in response to both extra- and intracellular signals has been a subject of interest to microbial physiologists for nearly four decades, beginning with the observations that Salmonella typhimurium cells grown on rich medium are larger and contain more RNA than those grown on poor medium. This was followed shortly by the discovery of the stringent response in Escherichia coli, which has continued to be the organism of choice for the study of rRNA synthesis. In this review, we summarize four general areas of E. coli rRNA transcription control: stringent control, growth rate regulation, upstream activation, and anti-termination. We also cite similar mechanisms in other bacteria and eukaryotes. The separation of growth rate-dependent control of rRNA synthesis from stringent control continues to be a subject of controversy. One model holds that the nucleotide ppGpp is the key effector for both mechanisms, while another school holds that it is unlikely that ppGpp or any other single effector is solely responsible for growth rate-dependent control. Recent studies on activation of rRNA synthesis by cis-acting upstream sequences has led to the discovery of a new class of promoters that make contact with RNA polymerase at a third position, called the UP element, in addition to the well-known -10 and -35 regions. Lastly, clues as to the role of antitermination in rRNA operons have begun to appear. Transcription complexes modified at the antiterminator site appear to elongate faster and are resistant to the inhibitory effects of ppGpp during the stringent response. PMID:8531889

  13. The origin of polynucleotide-directed protein synthesis

    NASA Technical Reports Server (NTRS)

    Orgel, Leslie E.

    1989-01-01

    If protein synthesis evolved in an RNA world it was probably preceded by simpler processes by means of which interaction with amino acids conferred selective advantage on replicating RNA molecules. It is suggested that at first the simple attachment of amino acids to the 2'(3') termini of RNA templates favored initiation of replication at the end of the template rather than at internal positions. The second stage in the evolution of protein synthesis would probably have been the association of pairs of charged RNA adaptors in such a way as to favor noncoded formation of peptides. Only after this process had become efficient could coded synthesis have begun.

  14. From "Cellular" RNA to "Smart" RNA: Multiple Roles of RNA in Genome Stability and Beyond.

    PubMed

    Michelini, Flavia; Jalihal, Ameya P; Francia, Sofia; Meers, Chance; Neeb, Zachary T; Rossiello, Francesca; Gioia, Ubaldo; Aguado, Julio; Jones-Weinert, Corey; Luke, Brian; Biamonti, Giuseppe; Nowacki, Mariusz; Storici, Francesca; Carninci, Piero; Walter, Nils G; Fagagna, Fabrizio d'Adda di

    2018-04-25

    Coding for proteins has been considered the main function of RNA since the "central dogma" of biology was proposed. The discovery of noncoding transcripts shed light on additional roles of RNA, ranging from the support of polypeptide synthesis, to the assembly of subnuclear structures, to gene expression modulation. Cellular RNA has therefore been recognized as a central player in often unanticipated biological processes, including genomic stability. This ever-expanding list of functions inspired us to think of RNA as a "smart" phone, which has replaced the older obsolete "cellular" phone. In this review, we summarize the last two decades of advances in research on the interface between RNA biology and genome stability. We start with an account of the emergence of noncoding RNA, and then we discuss the involvement of RNA in DNA damage signaling and repair, telomere maintenance, and genomic rearrangements. We continue with the depiction of single-molecule RNA detection techniques, and we conclude by illustrating the possibilities of RNA modulation in hopes of creating or improving new therapies. The widespread biological functions of RNA have made this molecule a reoccurring theme in basic and translational research, warranting it the transcendence from classically studied "cellular" RNA to "smart" RNA.

  15. Severe Acute Respiratory Syndrome Coronaviruses with Mutations in the E Protein Are Attenuated and Promising Vaccine Candidates

    PubMed Central

    Regla-Nava, Jose A.; Nieto-Torres, Jose L.; Jimenez-Guardeño, Jose M.; Fernandez-Delgado, Raul; Fett, Craig; Castaño-Rodríguez, Carlos; Perlman, Stanley; DeDiego, Marta L.

    2015-01-01

    ABSTRACT Severe acute respiratory syndrome coronavirus (SARS-CoV) causes a respiratory disease with a mortality rate of 10%. A mouse-adapted SARS-CoV (SARS-CoV-MA15) lacking the envelope (E) protein (rSARS-CoV-MA15-ΔE) is attenuated in vivo. To identify E protein regions and host responses that contribute to rSARS-CoV-MA15-ΔE attenuation, several mutants (rSARS-CoV-MA15-E*) containing point mutations or deletions in the amino-terminal or the carboxy-terminal regions of the E protein were generated. Amino acid substitutions in the amino terminus, or deletion of regions in the internal carboxy-terminal region of E protein, led to virus attenuation. Attenuated viruses induced minimal lung injury, diminished limited neutrophil influx, and increased CD4+ and CD8+ T cell counts in the lungs of BALB/c mice, compared to mice infected with the wild-type virus. To analyze the host responses leading to rSARS-CoV-MA15-E* attenuation, differences in gene expression elicited by the native and mutant viruses in the lungs of infected mice were determined. Expression levels of a large number of proinflammatory cytokines associated with lung injury were reduced in the lungs of rSARS-CoV-MA15-E*-infected mice, whereas the levels of anti-inflammatory cytokines were increased, both at the mRNA and protein levels. These results suggested that the reduction in lung inflammation together with a more robust antiviral T cell response contributed to rSARS-CoV-MA15-E* attenuation. The attenuated viruses completely protected mice against challenge with the lethal parental virus, indicating that these viruses are promising vaccine candidates. IMPORTANCE Human coronaviruses are important zoonotic pathogens. SARS-CoV caused a worldwide epidemic infecting more than 8,000 people with a mortality of around 10%. Therefore, understanding the virulence mechanisms of this pathogen and developing efficacious vaccines are of high importance to prevent epidemics from this and other human coronaviruses

  16. Synthesis and antisense properties of fluoro cyclohexenyl nucleic acid (F-CeNA), a nuclease stable mimic of 2'-fluoro RNA.

    PubMed

    Seth, Punit P; Yu, Jinghua; Jazayeri, Ali; Pallan, Pradeep S; Allerson, Charles R; Østergaard, Michael E; Liu, Fengwu; Herdewijn, Piet; Egli, Martin; Swayze, Eric E

    2012-06-01

    We report the design and synthesis of 2'-fluoro cyclohexenyl nucleic acid (F-CeNA) pyrimidine phosphoramidites and the synthesis and biophysical, structural, and biological evaluation of modified oligonucleotides. The synthesis of the nucleoside phosphoramidites was accomplished in multigram quantities starting from commercially available methyl-D-mannose pyranoside. Installation of the fluorine atom was accomplished using nonafluorobutanesulfonyl fluoride, and the cyclohexenyl ring system was assembled by means of a palladium-catalyzed Ferrier rearrangement. Installation of the nucleobase was carried out under Mitsunobu conditions followed by standard protecting group manipulations to provide the desired pyrimidine phosphoramidites. Biophysical evaluation indicated that F-CeNA shows behavior similar to that of a 2'-modified nucleotide, and duplexes with RNA showed slightly lower duplex thermostability as compared to that of the more rigid 3'-fluoro hexitol nucleic acid (FHNA). However, F-CeNA modified oligonucleotides were significantly more stable against digestion by snake venom phosphodiesterases (SVPD) as compared to unmodified DNA, 2'-fluoro RNA (FRNA), 2'-methoxyethyl RNA (MOE), and FHNA modified oligonucleotides. Examination of crystal structures of a modified DNA heptamer duplex d(GCG)-T*-d(GCG):d(CGCACGC) by X-ray crystallography indicated that the cyclohexenyl ring system exhibits both the (3)H(2) and (2)H(3) conformations, similar to the C3'-endo/C2'-endo conformation equilibrium seen in natural furanose nucleosides. In the (2)H(3) conformation, the equatorial fluorine engages in a relatively close contact with C8 (2.94 Å) of the 3'-adjacent dG nucleotide that may represent a pseudo hydrogen bond. In contrast, the cyclohexenyl ring of F-CeNA was found to exist exclusively in the (3)H(2) (C3'-endo like) conformation in the crystal structure of the modified A-form DNA decamer duplex [d(GCGTA)-T*-d(ACGC)](2.) In an animal experiment, a 16-mer F

  17. Bringing RNA Interference (RNAi) into the High School Classroom

    ERIC Educational Resources Information Center

    Sengupta, Sibani

    2013-01-01

    RNA interference (abbreviated RNAi) is a relatively new discovery in the field of mechanisms that serve to regulate gene expression (a.k.a. protein synthesis). Gene expression can be regulated at the transcriptional level (mRNA production, processing, or stability) and at the translational level (protein synthesis). RNAi acts in a gene-specific…

  18. Inactivation and safety testing of Middle East Respiratory Syndrome Coronavirus

    PubMed Central

    Kumar, Mia; Mazur, Steven; Ork, Britini L.; Postnikova, Elena; Hensley, Lisa E.; Jahrling, Peter B.; Johnson, Reed; Holbrook, Michael R.

    2015-01-01

    Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a recently emerged virus that has caused a number of human infections and deaths, primarily in the Middle East. The transmission of MERS-CoV to humans has been proposed to be as a result of contact with camels, but evidence of human-to-human transmission also exists. In order to work with MERS-CoV in a laboratory setting, the US Centers for Disease Control and Prevention (CDC) has determined that MERS-CoV should be handled at a biosafety level (BSL) 3 (BSL-3) biocontainment level. Many processes and procedures used to characterize MERS-CoV and to evaluate samples from MERS-CoV infected animals are more easily and efficiently completed at BSL-2 or lower containment. In order to complete experimental work at BSL-2, demonstration or proof of inactivation is required before removal of specimens from biocontainment laboratories. In the studies presented here, we evaluated typical means of inactivating viruses prior to handling specimens at a lower biocontainment level. We found that Trizol, AVL buffer and gamma irradiation were effective at inactivating MERS-CoV, that formaldehyde-based solutions required at least 30 minutes of contact time in a cell culture system while a mixture of methanol and acetone required 60 minutes to inactivate MERS-CoV. Together, these data provide a foundation for safely inactivating MERS-CoV, and potentially other coronaviruses, prior to removal from biocontainment facilities. PMID:26190637

  19. The persistent prevalence and evolution of cross-family recombinant coronavirus GCCDC1 among a bat population: a two-year follow-up.

    PubMed

    Obameso, Joseph O; Li, Hong; Jia, Hao; Han, Min; Zhu, Shiyan; Huang, Canping; Zhao, Yuhui; Zhao, Min; Bai, Yu; Yuan, Fei; Zhao, Honglan; Peng, Xia; Xu, Wen; Tan, Wenjie; Zhao, Yingze; Yuen, Kwok-Yung; Liu, William J; Lu, Lin; Gao, George F

    2017-12-01

    Bats are connected with the increasing numbers of emerging and re-emerging viruses that may break the species barrier and spread into the human population. Coronaviruses are one of the most common viruses discovered in bats, which were considered as the natural source of recent human-susceptible coronaviruses, i.e. SARS-COV and MERS-CoV. Our previous study reported the discovery of a bat-derived putative cross-family recombinant coronavirus with a reovirus gene p10, named as Ro-BatCoV GCCDC1. In this report, through a two-year follow-up of a special bat population in one specific cave of south China, we illustrate that Ro-BatCoV GCCDC1 persistently circulates among bats. Notably, through the longitudinal observation, we identified the dynamic evolution of Ro-BatCoV GCCDC1 in bats represented by continuously recombination events. Our study provides the first glimpse of the virus evolution in one longitudinally observed bat population cohort and underlines the surveillance and pre-warning of potential interspecies transmittable viruses in bats.

  20. Structure of human IFIT1 with capped RNA reveals adaptable mRNA binding and mechanisms for sensing N1 and N2 ribose 2′-O methylations

    PubMed Central

    Laudenbach, Beatrice Theres; Martínez-Montero, Saúl; Cencic, Regina; Habjan, Matthias; Pichlmair, Andreas; Damha, Masad J.; Pelletier, Jerry; Nagar, Bhushan

    2017-01-01

    IFIT1 (IFN-induced protein with tetratricopeptide repeats-1) is an effector of the host innate immune antiviral response that prevents propagation of virus infection by selectively inhibiting translation of viral mRNA. It relies on its ability to compete with the translation initiation factor eIF4F to specifically recognize foreign capped mRNAs, while remaining inactive against host mRNAs marked by ribose 2′-O methylation at the first cap-proximal nucleotide (N1). We report here several crystal structures of RNA-bound human IFIT1, including a 1.6-Å complex with capped RNA. IFIT1 forms a water-filled, positively charged RNA-binding tunnel with a separate hydrophobic extension that unexpectedly engages the cap in multiple conformations (syn and anti) giving rise to a relatively plastic and nonspecific mode of binding, in stark contrast to eIF4E. Cap-proximal nucleotides encircled by the tunnel provide affinity to compete with eIF4F while allowing IFIT1 to select against N1 methylated mRNA. Gel-shift binding assays confirm that N1 methylation interferes with IFIT1 binding, but in an RNA-dependent manner, whereas translation assays reveal that N1 methylation alone is not sufficient to prevent mRNA recognition at high IFIT1 concentrations. Structural and functional analysis show that 2′-O methylation at N2, another abundant mRNA modification, is also detrimental for RNA binding, thus revealing a potentially synergistic role for it in self- versus nonself-mRNA discernment. Finally, structure-guided mutational analysis confirms the importance of RNA binding for IFIT1 restriction of a human coronavirus mutant lacking viral N1 methylation. Our structural and biochemical analysis sheds new light on the molecular basis for IFIT1 translational inhibition of capped viral RNA. PMID:28251928

  1. Epidemiology, Genetic Recombination, and Pathogenesis of Coronaviruses.

    PubMed

    Su, Shuo; Wong, Gary; Shi, Weifeng; Liu, Jun; Lai, Alexander C K; Zhou, Jiyong; Liu, Wenjun; Bi, Yuhai; Gao, George F

    2016-06-01

    Human coronaviruses (HCoVs) were first described in the 1960s for patients with the common cold. Since then, more HCoVs have been discovered, including those that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), two pathogens that, upon infection, can cause fatal respiratory disease in humans. It was recently discovered that dromedary camels in Saudi Arabia harbor three different HCoV species, including a dominant MERS HCoV lineage that was responsible for the outbreaks in the Middle East and South Korea during 2015. In this review we aim to compare and contrast the different HCoVs with regard to epidemiology and pathogenesis, in addition to the virus evolution and recombination events which have, on occasion, resulted in outbreaks amongst humans. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Molecular evolution and emergence of avian gammacoronaviruses.

    PubMed

    Jackwood, Mark W; Hall, David; Handel, Andreas

    2012-08-01

    Coronaviruses, which are single stranded, positive sense RNA viruses, are responsible for a wide variety of existing and emerging diseases in humans and other animals. The gammacoronaviruses primarily infect avian hosts. Within this genus of coronaviruses, the avian coronavirus infectious bronchitis virus (IBV) causes a highly infectious upper-respiratory tract disease in commercial poultry. IBV shows rapid evolution in chickens, frequently producing new antigenic types, which adds to the multiple serotypes of the virus that do not cross protect. Rapid evolution in IBV is facilitated by strong selection, large population sizes and high genetic diversity within hosts, and transmission bottlenecks between hosts. Genetic diversity within a host arises primarily by mutation, which includes substitutions, insertions and deletions. Mutations are caused both by the high error rate, and limited proof reading capability, of the viral RNA-dependent RNA-polymerase, and by recombination. Recombination also generates new haplotype diversity by recombining existing variants. Rapid evolution of avian coronavirus IBV makes this virus extremely difficult to diagnose and control, but also makes it an excellent model system to study viral genetic diversity and the mechanisms behind the emergence of coronaviruses in their natural host. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. 2'-Bispyrene-modified 2'-O-methyl RNA probes as useful tools for the detection of RNA: synthesis, fluorescent properties, and duplex stability.

    PubMed

    Krasheninina, Olga A; Novopashina, Darya S; Lomzov, Alexander A; Venyaminova, Alya G

    2014-09-05

    The synthesis and properties two series of new 2'-O-methyl RNA probes, each containing a single insertion of a 2'-bispyrenylmethylphosphorodiamidate derivative of a nucleotide (U, C, A, and G), are described. As demonstrated by UV melting studies, the probes form stable complexes with model RNAs and DNAs. Significant increases (up to 21-fold) in pyrene excimer fluorescence intensity were observed upon binding of most of the probes with complementary RNAs, but not with DNAs. The fluorescence spectra are independent of the nature of the modified nucleotides. The nucleotides on the 5'-side of the modified nucleotide have no effect on the fluorescence spectra, whereas the natures of the two nucleotides on the 3'-side are important: CC, CG, and UC dinucleotide units on the 3'-side of the modified nucleotide provide the maximum increases in excimer fluorescence intensity. This study suggests that these 2'-bispyrene-labeled 2'-O-methyl RNA probes might be useful tools for detection of RNAs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Template switching between PNA and RNA oligonucleotides

    NASA Technical Reports Server (NTRS)

    Bohler, C.; Nielsen, P. E.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

    1995-01-01

    The origin of the RNA world is not easily understood, as effective prebiotic syntheses of the components of RNA, the beta-ribofuranoside-5'-phosphates, are hard to envisage. Recognition of this difficulty has led to the proposal that other genetic systems, the components of which are more easily formed, may have preceded RNA. This raises the question of how transitions between one genetic system and another could occur. Peptide nucleic acid (PNA) resembles RNA in its ability to form double-helical complexes stabilized by Watson-Crick hydrogen bonding between adenine and thymine and between cytosine and guanine, but has a backbone that is held together by amide rather than by phosphodiester bonds. Oligonucleotides bases on RNA are known to act as templates that catalyse the non-enzymatic synthesis of their complements from activated mononucleotides, we now show that RNA oligonucleotides facilitate the synthesis of complementary PNA strands and vice versa. This suggests that a transition between different genetic systems can occur without loss of information.

  5. Recent Transmission of a Novel Alphacoronavirus, Bat Coronavirus HKU10, from Leschenault's Rousettes to Pomona Leaf-Nosed Bats: First Evidence of Interspecies Transmission of Coronavirus between Bats of Different Suborders

    PubMed Central

    Lau, Susanna K. P.; Li, Kenneth S. M.; Tsang, Alan K. L.; Shek, Chung-Tong; Wang, Ming; Choi, Garnet K. Y.; Guo, Rongtong; Wong, Beatrice H. L.; Poon, Rosana W. S.; Lam, Carol S. F.; Wang, Sylvia Y. H.; Fan, Rachel Y. Y.; Chan, Kwok-Hung; Zheng, Bo-Jian

    2012-01-01

    Although coronaviruses are known to infect various animals by adapting to new hosts, interspecies transmission events are still poorly understood. During a surveillance study from 2005 to 2010, a novel alphacoronavirus, BatCoV HKU10, was detected in two very different bat species, Ro-BatCoV HKU10 in Leschenault's rousettes (Rousettus leschenaulti) (fruit bats in the suborder Megachiroptera) in Guangdong and Hi-BatCoV HKU10 in Pomona leaf-nosed bats (Hipposideros pomona) (insectivorous bats in the suborder Microchiroptera) in Hong Kong. Although infected bats appeared to be healthy, Pomona leaf-nosed bats carrying Hi-BatCoV HKU10 had lower body weights than uninfected bats. To investigate possible interspecies transmission between the two bat species, the complete genomes of two Ro-BatCoV HKU10 and six Hi-BatCoV HKU10 strains were sequenced. Genome and phylogenetic analyses showed that Ro-BatCoV HKU10 and Hi-BatCoV HKU10 represented a novel alphacoronavirus species, sharing highly similar genomes except in the genes encoding spike proteins, which had only 60.5% amino acid identities. Evolution of the spike protein was also rapid in Hi-BatCoV HKU10 strains from 2005 to 2006 but stabilized thereafter. Molecular-clock analysis dated the most recent common ancestor of all BatCoV HKU10 strains to 1959 (highest posterior density regions at 95% [HPDs], 1886 to 2002) and that of Hi-BatCoV HKU10 to 1986 (HPDs, 1956 to 2004). The data suggested recent interspecies transmission from Leschenault's rousettes to Pomona leaf-nosed bats in southern China. Notably, the rapid adaptive genetic change in BatCoV HKU10 spike protein by ∼40% amino acid divergence after recent interspecies transmission was even greater than the ∼20% amino acid divergence between spike proteins of severe acute respiratory syndrome-related Rhinolophus bat coronavirus (SARSr-CoV) in bats and civets. This study provided the first evidence for interspecies transmission of coronavirus between bats of

  6. Synthesis and Labeling of RNA In Vitro

    PubMed Central

    Huang, Chao; Yu, Yi-Tao

    2013-01-01

    This unit discusses several methods for generating large amounts of uniformly labeled, end-labeled, and site-specifically labeled RNAs in vitro. The methods involve a number of experimental procedures, including RNA transcription, 5′ dephosphorylation and rephosphorylation, 3′ terminal nucleotide addition (via ligation), site-specific RNase H cleavage directed by 2′-O-methyl RNA-DNA chimeras, and 2-piece splint ligation. The applications of these RNA radiolabeling approaches are also discussed. PMID:23547015

  7. Novel coronaviruses, astroviruses, adenoviruses and circoviruses in insectivorous bats from northern China.

    PubMed

    Han, H-J; Wen, H-L; Zhao, L; Liu, J-W; Luo, L-M; Zhou, C-M; Qin, X-R; Zhu, Y-L; Liu, M-M; Qi, R; Li, W-Q; Yu, H; Yu, X-J

    2017-12-01

    Bats are considered as the reservoirs of several emerging infectious disease, and novel viruses are continually found in bats all around the world. Studies conducted in southern China found that bats carried a variety of viruses. However, few studies have been conducted on bats in northern China, which harbours a diversity of endemic insectivorous bats. It is important to understand the prevalence and diversity of viruses circulating in bats in northern China. In this study, a total of 145 insectivorous bats representing six species were collected from northern China and screened with degenerate primers for viruses belonging to six families, including coronaviruses, astroviruses, hantaviruses, paramyxoviruses, adenoviruses and circoviruses. Our study found that four of the viruses screened for were positive and the overall detection rates for astroviruses, coronaviruses, adenoviruses and circoviruses in bats were 21.4%, 15.9%, 20% and 37.2%, respectively. In addition, we found that bats in northern China harboured a diversity of novel viruses. Common Serotine (Eptesicus serotinu), Fringed long-footed Myotis (Myotis fimriatus) and Peking Myotis (Myotis pequinius) were investigated in China for the first time. Our study provided new information on the ecology and phylogeny of bat-borne viruses. © 2017 The Authors. Zoonoses and Public Health Published by Blackwell Verlag GmbH.

  8. Airway Memory CD4(+) T Cells Mediate Protective Immunity against Emerging Respiratory Coronaviruses.

    PubMed

    Zhao, Jincun; Zhao, Jingxian; Mangalam, Ashutosh K; Channappanavar, Rudragouda; Fett, Craig; Meyerholz, David K; Agnihothram, Sudhakar; Baric, Ralph S; David, Chella S; Perlman, Stanley

    2016-06-21

    Two zoonotic coronaviruses (CoVs)-SARS-CoV and MERS-CoV-have crossed species to cause severe human respiratory disease. Here, we showed that induction of airway memory CD4(+) T cells specific for a conserved epitope shared by SARS-CoV and MERS-CoV is a potential strategy for developing pan-coronavirus vaccines. Airway memory CD4(+) T cells differed phenotypically and functionally from lung-derived cells and were crucial for protection against both CoVs in mice. Protection was dependent on interferon-γ and required early induction of robust innate and virus-specific CD8(+) T cell responses. The conserved epitope was also recognized in SARS-CoV- and MERS-CoV-infected human leukocyte antigen DR2 and DR3 transgenic mice, indicating potential relevance in human populations. Additionally, this epitope was cross-protective between human and bat CoVs, the progenitors for many human CoVs. Vaccine strategies that induce airway memory CD4(+) T cells targeting conserved epitopes might have broad applicability in the context of new CoVs and other respiratory virus outbreaks. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Synthesis of 4'-Selenoribonucleosides, the Building Blocks of 4'-SelenoRNA, Using a Hypervalent Iodine.

    PubMed

    Saito-Tarashima, Noriko; Ota, Masashi; Minakawa, Noriaki

    2017-09-18

    Herein is described a detailed protocol for the synthesis of 4'-selenoribonucleoside derivatives that involves the use of a hypervalent iodine species. These derivatives are versatile units for the preparation of 4'-selenoRNA. Large-scale synthesis of a 4-selenosugar starting from D-ribose is achieved in eight steps, including a final chromatographic purification. The resulting 4-selenosugar is then subjected to the one-pot Pummerer-like reaction using hypervalent iodine in the presence of silylated nucleobases. The reaction with silylated uracil affords the desired 4'-selenouridine derivatives with excellent β-selectivity and in good yield. Conversely, when purine nucleobases are used in the Pummerer-like reaction, N7 4'-selenoribonucleoside isomers are obtained alongside the desired N9 isomers. However, the undesired N7 isomers can be converted to the desired N9 ones under acidic conditions. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  10. Spontaneous reverse movement of mRNA-bound tRNA through the ribosome.

    PubMed

    Konevega, Andrey L; Fischer, Niels; Semenkov, Yuri P; Stark, Holger; Wintermeyer, Wolfgang; Rodnina, Marina V

    2007-04-01

    During the translocation step of protein synthesis, a complex of two transfer RNAs bound to messenger RNA (tRNA-mRNA) moves through the ribosome. The reaction is promoted by an elongation factor, called EF-G in bacteria, which, powered by GTP hydrolysis, induces an open, unlocked conformation of the ribosome that allows for spontaneous tRNA-mRNA movement. Here we show that, in the absence of EF-G, there is spontaneous backward movement, or retrotranslocation, of two tRNAs bound to mRNA. Retrotranslocation is driven by the gain in affinity when a cognate E-site tRNA moves into the P site, which compensates the affinity loss accompanying the movement of peptidyl-tRNA from the P to the A site. These results lend support to the diffusion model of tRNA movement during translocation. In the cell, tRNA movement is biased in the forward direction by EF-G, which acts as a Brownian ratchet and prevents backward movement.

  11. tRNA wobble modifications and protein homeostasis

    PubMed Central

    Ranjan, Namit; Rodnina, Marina V.

    2016-01-01

    Abstract tRNA is a central component of the protein synthesis machinery in the cell. In living cells, tRNAs undergo numerous post-transcriptional modifications. In particular, modifications at the anticodon loop play an important role in ensuring efficient protein synthesis, maintaining protein homeostasis, and helping cell adaptation and survival. Hypo-modification of the wobble position of the tRNA anticodon loop is of particular relevance for translation regulation and is implicated in various human diseases. In this review we summarize recent evidence of how methyl and thiol modifications in eukaryotic tRNA at position 34 affect cellular fitness and modulate regulatory circuits at normal conditions and under stress. PMID:27335723

  12. European Surveillance for Pantropic Canine Coronavirus

    PubMed Central

    Cordonnier, Nathalie; Demeter, Zoltan; Egberink, Herman; Elia, Gabriella; Grellet, Aurélien; Le Poder, Sophie; Mari, Viviana; Martella, Vito; Ntafis, Vasileios; von Reitzenstein, Marcela; Rottier, Peter J.; Rusvai, Miklos; Shields, Shelly; Xylouri, Eftychia; Xu, Zach; Buonavoglia, Canio

    2013-01-01

    Highly virulent pantropic canine coronavirus (CCoV) strains belonging to subtype IIa were recently identified in dogs. To assess the distribution of such strains in Europe, tissue samples were collected from 354 dogs that had died after displaying systemic disease in France (n = 92), Hungary (n = 75), Italy (n = 69), Greece (n = 87), The Netherlands (n = 27), Belgium (n = 4), and Bulgaria (n = 1). A total of 124 animals tested positive for CCoV, with 33 of them displaying the virus in extraintestinal tissues. Twenty-four CCoV strains (19.35% of the CCoV-positive dogs) detected in internal organs were characterized as subtype IIa and consequently assumed to be pantropic CCoVs. Sequence and phylogenetic analyses of the 5′ end of the spike protein gene showed that pantropic CCoV strains are closely related to each other, with the exception of two divergent French viruses that clustered with enteric strains. PMID:23100349

  13. Influence of mRNA and protein synthesis inhibitors on the long-term memory acquisition of classically conditioned earthworms.

    PubMed

    Watanabe, Hikaru; Takaya, Tomohiro; Shimoi, Toshinobu; Ogawa, Hiroto; Kitamura, Yoshiichiro; Oka, Kotaro

    2005-03-01

    We investigated the process of memory consolidation following classical conditioning of earthworms. Earthworms were conditioned in paired trials by a weak vibration as a conditioned stimulus (CS), and by light as an unconditioned stimulus (US). The occurrence of a shrinking response upon exposure to the CS increased steadily with the number of paired training trials. When the training procedure was changed by increasing the intertrial interval (ITI), it was found that only those worms trained with a 68 s ITI exhibited long-term memory retention for at least 24 h. The influence of mRNA synthesis inhibition by actinomycin-D or of protein synthesis by anisomycin on memory consolidation was also examined. Induction of the long-term memory was blocked when either of these two compounds was injected into the body cavity of the worm within 25 min of conditioning with the 68 s ITI. These results demonstrate that the long-term memory is dependent upon protein synthesis in response to the upregulation of new transcription messengers.

  14. Computational modeling of the bat HKU4 coronavirus 3CLpro inhibitors as a tool for the development of antivirals against the emerging Middle East respiratory syndrome (MERS) coronavirus.

    PubMed

    Abuhammad, Areej; Al-Aqtash, Rua'a A; Anson, Brandon J; Mesecar, Andrew D; Taha, Mutasem O

    2017-11-01

    The Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging virus that poses a major challenge to clinical management. The 3C-like protease (3CL pro ) is essential for viral replication and thus represents a potential target for antiviral drug development. Presently, very few data are available on MERS-CoV 3CL pro inhibition by small molecules. We conducted extensive exploration of the pharmacophoric space of a recently identified set of peptidomimetic inhibitors of the bat HKU4-CoV 3CL pro . HKU4-CoV 3CL pro shares high sequence identity (81%) with the MERS-CoV enzyme and thus represents a potential surrogate model for anti-MERS drug discovery. We used 2 well-established methods: Quantitative structure-activity relationship (QSAR)-guided modeling and docking-based comparative intermolecular contacts analysis. The established pharmacophore models highlight structural features needed for ligand recognition and revealed important binding-pocket regions involved in 3CL pro -ligand interactions. The best models were used as 3D queries to screen the National Cancer Institute database for novel nonpeptidomimetic 3CL pro inhibitors. The identified hits were tested for HKU4-CoV and MERS-CoV 3CL pro inhibition. Two hits, which share the phenylsulfonamide fragment, showed moderate inhibitory activity against the MERS-CoV 3CL pro and represent a potential starting point for the development of novel anti-MERS agents. To the best of our knowledge, this is the first pharmacophore modeling study supported by in vitro validation on the MERS-CoV 3CL pro . MERS-CoV is an emerging virus that is closely related to the bat HKU4-CoV. 3CL pro is a potential drug target for coronavirus infection. HKU4-CoV 3CL pro is a useful surrogate model for the identification of MERS-CoV 3CL pro enzyme inhibitors. dbCICA is a very robust modeling method for hit identification. The phenylsulfonamide scaffold represents a potential starting point for MERS coronavirus 3CL pro inhibitors

  15. Synthesis of 4'-C-aminoalkyl-2'-O-methyl modified RNA and their biological properties.

    PubMed

    Koizumi, Kana; Maeda, Yusuke; Kano, Toshifumi; Yoshida, Hisae; Sakamoto, Taiichi; Yamagishi, Kenji; Ueno, Yoshihito

    2018-05-17

    In this paper, we describe the synthesis of 4'-C-aminoalkyl-2'-O-methylnucleosides and the properties of RNAs containing these analogs. Phosphoramidites of 4'-C-aminoethyl and 4'-C-aminopropyl-2'-O-methyluridines were prepared using glucose as starting material, and RNAs containing the analogs were synthesized using the phosphoramidites. Thermal denaturation studies revealed that these nucleoside analogs decreased the thermal stabilities of double-stranded RNAs (dsRNAs). Results of NMR, molecular modeling, and CD spectra measurements suggested that 4'-C-aminoalkyl-2'-O-methyluridine adopts an C2'-endo sugar puckering in dsRNA. The 4'-C-aminoalkyl modifications in the passenger strand and the guide strand outside the seed region were well tolerated for RNAi activity of siRNAs. Single-stranded RNAs (ssRNAs) and siRNAs containing the 4'-C-aminoethyl and 4'-C-aminopropyl analogs showed high stability in buffer containing bovine serum. Thus, siRNAs containing the 4'-C-aminoethyl and 4'-C-aminopropyl analogs are good candidates for the development of therapeutic siRNA molecules. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. In Vitro Antiviral Activity of Circular Triple Helix Forming Oligonucleotide RNA towards Feline Infectious Peritonitis Virus Replication

    PubMed Central

    Choong, Oi Kuan; Tejo, Bimo Ario; Omar, Abdul Rahman

    2014-01-01

    Feline Infectious Peritonitis (FIP) is a severe fatal immune-augmented disease in cat population. It is caused by FIP virus (FIPV), a virulent mutant strain of Feline Enteric Coronavirus (FECV). Current treatments and prophylactics are not effective. The in vitro antiviral properties of five circular Triple-Helix Forming Oligonucleotide (TFO) RNAs (TFO1 to TFO5), which target the different regions of virulent feline coronavirus (FCoV) strain FIPV WSU 79-1146 genome, were tested in FIPV-infected Crandell-Rees Feline Kidney (CRFK) cells. RT-qPCR results showed that the circular TFO RNAs, except TFO2, inhibit FIPV replication, where the viral genome copy numbers decreased significantly by 5-fold log10 from 1014 in the virus-inoculated cells to 109 in the circular TFO RNAs-transfected cells. Furthermore, the binding of the circular TFO RNA with the targeted viral genome segment was also confirmed using electrophoretic mobility shift assay. The strength of binding kinetics between the TFO RNAs and their target regions was demonstrated by NanoITC assay. In conclusion, the circular TFOs have the potential to be further developed as antiviral agents against FIPV infection. PMID:24707494

  17. Circular RNA (circRNA) was an important bridge in the switch from the RNA world to the DNA world.

    PubMed

    Soslau, Gerald

    2018-06-14

    osmolarity. Circular RNA, circRNA, is proposed as a critical stable RNA molecule that served as the genetic precursor for the switch to DNA and the replication of circRNA by a rolling circle mechanism gave rise to the RNA complexity required for the genetic functions of the cell. The replicating ribocyte would have required protein synthesis as well as RNA replication and a model for non-coded and primordial coded protein synthesis is proposed. Finally, the switch from the RNA to the DNA world would have involved the synthesis of an RNA:DNA hybrid prior to the formation of dsDNA. If the hybrid was a circular molecule that ultimately yielded a circular dsDNA molecule, it could predict that the primordial DNA cell would evolve into a bacterial cell with a single circular chromosome. One would hope that continued speculation of the origin of life will spur new directions of research that may never fully answer the questions of the past but add to our ability to regulate potentially harmful biological events in the present and in the future. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. The Bacillus subtilis and Bacillus halodurans Aspartyl-tRNA Synthetases Retain Recognition of tRNA(Asn).

    PubMed

    Nair, Nilendra; Raff, Hannah; Islam, Mohammed Tarek; Feen, Melanie; Garofalo, Denise M; Sheppard, Kelly

    2016-02-13

    Synthesis of asparaginyl-tRNA (Asn-tRNA(Asn)) in bacteria can be formed either by directly ligating Asn to tRNA(Asn) using an asparaginyl-tRNA synthetase (AsnRS) or by synthesizing Asn on the tRNA. In the latter two-step indirect pathway, a non-discriminating aspartyl-tRNA synthetase (ND-AspRS) attaches Asp to tRNA(Asn) and the amidotransferase GatCAB transamidates the Asp to Asn on the tRNA. GatCAB can be similarly used for Gln-tRNA(Gln) formation. Most bacteria are predicted to use only one route for Asn-tRNA(Asn) formation. Given that Bacillus halodurans and Bacillus subtilis encode AsnRS for Asn-tRNA(Asn) formation and Asn synthetases to synthesize Asn and GatCAB for Gln-tRNA(Gln) synthesis, their AspRS enzymes were thought to be specific for tRNA(Asp). However, we demonstrate that the AspRSs are non-discriminating and can be used with GatCAB to synthesize Asn. The results explain why B. subtilis with its Asn synthetase genes knocked out is still an Asn prototroph. Our phylogenetic analysis suggests that this may be common among Firmicutes and 30% of all bacteria. In addition, the phylogeny revealed that discrimination toward tRNA(Asp) by AspRS has evolved independently multiple times. The retention of the indirect pathway in B. subtilis and B. halodurans likely reflects the ancient link between Asn biosynthesis and its use in translation that enabled Asn to be added to the genetic code. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Comprehensive Identification of RNA-Binding Proteins by RNA Interactome Capture.

    PubMed

    Castello, Alfredo; Horos, Rastislav; Strein, Claudia; Fischer, Bernd; Eichelbaum, Katrin; Steinmetz, Lars M; Krijgsveld, Jeroen; Hentze, Matthias W

    2016-01-01

    RNA associates with RNA-binding proteins (RBPs) from synthesis to decay, forming dynamic ribonucleoproteins (RNPs). In spite of the preeminent role of RBPs regulating RNA fate, the scope of cellular RBPs has remained largely unknown. We have recently developed a novel and comprehensive method to identify the repertoire of active RBPs of cultured cells, called RNA interactome capture. Using in vivo UV cross-linking on cultured cells, proteins are covalently bound to RNA if the contact between the two is direct ("zero distance"). Protein-RNA complexes are purified by poly(A) tail-dependent oligo(dT) capture and analyzed by quantitative mass spectrometry. Because UV irradiation is applied to living cells and purification is performed using highly stringent washes, RNA interactome capture identifies physiologic and direct protein-RNA interactions. Applied to HeLa cells, this protocol revealed the near-complete repertoire of RBPs, including hundreds of novel RNA binders. Apart from its RBP discovery capacity, quantitative and comparative RNA interactome capture can also be used to study the responses of the RBP repertoire to different physiological cues and processes, including metabolic stress, differentiation, development, or the response to drugs.

  20. Severe acute respiratory syndrome coronavirus replication inhibitor that interferes with the nucleic acid unwinding of the viral helicase.

    PubMed

    Adedeji, Adeyemi O; Singh, Kamalendra; Calcaterra, Nicholas E; DeDiego, Marta L; Enjuanes, Luis; Weiss, Susan; Sarafianos, Stefan G

    2012-09-01

    Severe acute respiratory syndrome (SARS) is a highly contagious disease, caused by SARS coronavirus (SARS-CoV), for which there are no approved treatments. We report the discovery of a potent inhibitor of SARS-CoV that blocks replication by inhibiting the unwinding activity of the SARS-CoV helicase (nsp13). We used a Förster resonance energy transfer (FRET)-based helicase assay to screen the Maybridge Hitfinder chemical library. We identified and validated a compound (SSYA10-001) that specifically blocks the double-stranded RNA (dsRNA) and dsDNA unwinding activities of nsp13, with 50% inhibitory concentrations (IC(50)s) of 5.70 and 5.30 μM, respectively. This compound also has inhibitory activity (50% effective concentration [EC(50)] = 8.95 μM) in a SARS-CoV replicon assay, with low cytotoxicity (50% cytotoxic concentration [CC(50)] = >250 μM), suggesting that the helicase plays a still unidentified critical role in the SARS-CoV life cycle. Enzyme kinetic studies on the mechanism of nsp13 inhibition revealed that SSYA10-001 acts as a noncompetitive inhibitor of nsp13 with respect to nucleic acid and ATP substrates. Moreover, SSYA10-001 does not affect ATP hydrolysis or nsp13 binding to the nucleic acid substrate. SSYA10-001 did not inhibit hepatitis C virus (HCV) helicase, other bacterial and viral RNA-dependent RNA polymerases, or reverse transcriptase. These results suggest that SSYA10-001 specifically blocks nsp13 through a novel mechanism and is less likely to interfere with the functions of cellular enzymes that process nucleic acids or ATP. Hence, it is possible that SSYA10-001 inhibits unwinding by nsp13 by affecting conformational changes during the course of the reaction or translocation on the nucleic acid. SSYA10-001 will be a valuable tool for studying the specific role of nsp13 in the SARS-CoV life cycle, which could be a model for other nidoviruses and also a candidate for further development as a SARS antiviral target.

  1. Importance of Conserved Cysteine Residues in the Coronavirus Envelope Protein▿

    PubMed Central

    Lopez, Lisa A.; Riffle, Ambere J.; Pike, Steven L.; Gardner, Douglas; Hogue, Brenda G.

    2008-01-01

    Coronavirus envelope (E) proteins play an important, not fully understood role(s) in the virus life cycle. All E proteins have conserved cysteine residues located on the carboxy side of the long hydrophobic domain, suggesting functional significance. In this study, we confirmed that mouse hepatitis coronavirus A59 E protein is palmitoylated. To understand the role of the conserved residues and the necessity of palmitoylation, three cysteines at positions 40, 44, and 47 were changed singly and in various combinations to alanine. Double- and triple-mutant E proteins resulted in decreased virus-like particle output when coexpressed with the membrane (M) protein. Mutant E proteins were also studied in the context of a full-length infectious clone. Single-substitution viruses exhibited growth characteristics virtually identical to those of the wild-type virus, while the double-substitution mutations gave rise to viruses with less robust growth phenotypes indicated by smaller plaques and decreased virus yields. In contrast, replacement of all three cysteines resulted in crippled virus with significantly reduced yields. Triple-mutant viruses did not exhibit impairment in entry. Mutant E proteins localized properly in infected cells. A comparison of intracellular and extracellular virus yields suggested that release is only slightly impaired. E protein lacking all three cysteines exhibited an increased rate of degradation compared to that of the wild-type protein, suggesting that palmitoylation is important for the stability of the protein. Altogether, the results indicate that the conserved cysteines and presumably palmitoylation are functionally important for virus production. PMID:18184703

  2. Mutational analysis reveals a noncontractile but interactive role of actin and profilin in viral RNA-dependent RNA synthesis.

    PubMed

    Harpen, Mary; Barik, Tiasha; Musiyenko, Alla; Barik, Sailen

    2009-11-01

    As obligatory parasites, viruses co-opt a variety of cellular functions for robust replication. The expression of the nonsegmented negative-strand RNA genome of respiratory syncytial virus (RSV), a significant pediatric pathogen, absolutely requires actin and is stimulated by the actin-regulatory protein profilin. As actin is a major contractile protein, it was important to determine whether the known functional domains of actin and profilin were important for their ability to activate RSV transcription. Analyses of recombinant mutants in a reconstituted RSV transcription system suggested that the divalent-cation-binding domain of actin is critically needed for binding to the RSV genome template and for the activation of viral RNA synthesis. In contrast, the nucleotide-binding domain and the N-terminal acidic domain were needed neither for template binding nor for transcription. Specific surface residues of actin, required for actin-actin contact during filamentation, were also nonessential for viral transcription. Unlike actin, profilin did not directly bind to the viral template but was recruited by actin. Mutation of the interactive residues of actin or profilin, resulting in the loss of actin-profilin binding, also abolished profilin's ability to stimulate viral transcription. Together, these results suggest that actin acts as a classical transcription factor for the virus by divalent-cation-dependent binding to the viral template and that profilin acts as a transcriptional cofactor, in part by associating with actin. This essential viral role of actin is independent of its contractile cellular role.

  3. Determination of in vivo RNA kinetics using RATE-seq.

    PubMed

    Neymotin, Benjamin; Athanasiadou, Rodoniki; Gresham, David

    2014-10-01

    The abundance of a transcript is determined by its rate of synthesis and its rate of degradation; however, global methods for quantifying RNA abundance cannot distinguish variation in these two processes. Here, we introduce RNA approach to equilibrium sequencing (RATE-seq), which uses in vivo metabolic labeling of RNA and approach to equilibrium kinetics, to determine absolute RNA degradation and synthesis rates. RATE-seq does not disturb cellular physiology, uses straightforward normalization with exogenous spike-ins, and can be readily adapted for studies in most organisms. We demonstrate the use of RATE-seq to estimate genome-wide kinetic parameters for coding and noncoding transcripts in Saccharomyces cerevisiae. © 2014 Neymotin et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  4. Reverse transcription of phage RNA and its fragment directed by synthetic heteropolymeric primers

    PubMed Central

    Frolova, L. Yu.; Metelyev, V. G.; Ratmanova, K. I.; Smirnov, V. D.; Shabarova, Z. A.; Prokofyev, M. A.; Berzin, V. M.; Jansone, I. V.; Gren, E. J.; Kisselev, L. L.

    1977-01-01

    DNA synthesis catalysed by RNA-directed DNA-polymerase (reverse transcriptase) was found to proceed on the RNA template of an MS2 phage in the presence of heteropolymeric synthetic octa- and nonadeoxyribonucleotide primers complementary to the intercistronic region (coat protein binding site) and the region of the coat protein cistron, respectively. The product of synthesis consists of discrete DNA fractions of different length, including transcripts longer than 1,000 nucleotides. The coat protein inhibits DNA synthesis if it is initiated at its binding site, but has no effect on DNA synthesis initiated at the coat protein cistron. It has been suggested that, in this system, the initiation of DNA synthesis by synthetic primers is topographically specific. The MS2 coat protein binding site (an RNA fragment of 59 nucleotides) serves as a template for polydeoxyribonucleotide synthesis in the presence of octanucleotide primer and reverse transcriptase. The product of synthesis is homogenous and its length corresponds to the length of the template. The effective and complete copying of the fragment having a distinct secondary structure proves that the secondary structure does not interfere, in principle, with RNA being a template in the system of reverse transcription. PMID:71713

  5. Switch from translation to RNA replication in a positive-stranded RNA virus

    PubMed Central

    Gamarnik, Andrea V.; Andino, Raul

    1998-01-01

    In positive-stranded viruses, the genomic RNA serves as a template for both translation and RNA replication. Using poliovirus as a model, we examined the interaction between these two processes. We show that the RNA polymerase is unable to replicate RNA templates undergoing translation. We discovered that an RNA structure at the 5′ end of the viral genome, next to the internal ribosomal entry site, carries signals that control both viral translation and RNA synthesis. The interaction of this RNA structure with the cellular factor PCBP up-regulates viral translation, while the binding of the viral protein 3CD represses translation and promotes negative-strand RNA synthesis. We propose that the interaction of 3CD with this RNA structure controls whether the genomic RNA is used for translation or RNA replication. PMID:9694795

  6. Genetic diversity of bats coronaviruses in the Atlantic Forest hotspot biome, Brazil.

    PubMed

    Góes, Luiz Gustavo Bentim; Campos, Angélica Cristine de Almeida; Carvalho, Cristiano de; Ambar, Guilherme; Queiroz, Luzia Helena; Cruz-Neto, Ariovaldo Pereira; Munir, Muhammad; Durigon, Edison Luiz

    2016-10-01

    Bats are notorious reservoirs of genetically-diverse and high-profile pathogens, and are playing crucial roles in the emergence and re-emergence of viruses, both in human and in animals. In this report, we identified and characterized previously unknown and diverse genetic clusters of bat coronaviruses in the Atlantic Forest Biome, Brazil. These results highlight the virus richness of bats and their possible roles in the public health. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Functional RNA elements in the dengue virus genome.

    PubMed

    Gebhard, Leopoldo G; Filomatori, Claudia V; Gamarnik, Andrea V

    2011-09-01

    Dengue virus (DENV) genome amplification is a process that involves the viral RNA, cellular and viral proteins, and a complex architecture of cellular membranes. The viral RNA is not a passive template during this process; it plays an active role providing RNA signals that act as promoters, enhancers and/or silencers of the replication process. RNA elements that modulate RNA replication were found at the 5' and 3' UTRs and within the viral coding sequence. The promoter for DENV RNA synthesis is a large stem loop structure located at the 5' end of the genome. This structure specifically interacts with the viral polymerase NS5 and promotes RNA synthesis at the 3' end of a circularized genome. The circular conformation of the viral genome is mediated by long range RNA-RNA interactions that span thousands of nucleotides. Recent studies have provided new information about the requirement of alternative, mutually exclusive, structures in the viral RNA, highlighting the idea that the viral genome is flexible and exists in different conformations. In this article, we describe elements in the promoter SLA and other RNA signals involved in NS5 polymerase binding and activity, and provide new ideas of how dynamic secondary and tertiary structures of the viral RNA participate in the viral life cycle.

  8. The control of paramyxovirus genome hexamer length and mRNA editing.

    PubMed

    Matsumoto, Yusuke; Ohta, Keisuke; Kolakofsky, Daniel; Nishio, Machiko

    2018-04-01

    The unusual ability of a human parainfluenza virus type 2 (hPIV2) nucleoprotein point mutation (NP Q202A ) to strongly enhance minigenome replication was found to depend on the absence of a functional, internal element of the bipartite replication promoter (CRII). This point mutation allows relatively robust CRII-minus minigenome replication in a CRII-independent manner, under conditions in which NP wt is essentially inactive. The nature of the amino acid at position 202 apparently controls whether viral RNA-dependent RNA polymerase (vRdRp) can, or cannot, initiate RNA synthesis in a CRII-independent manner. By repressing genome synthesis when vRdRp cannot correctly interact with CRII, gln 202 of N, the only residue of the RNA-binding groove that contacts a nucleotide base in the N-RNA, acts as a gatekeeper for wild-type (CRII-dependent) RNA synthesis. This ensures that only hexamer-length genomes are replicated, and that the critical hexamer phase of the cis -acting mRNA editing sequence is maintained. © 2018 Matsumoto et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  9. Temperature requirements for initiation of RNA-dependent RNA polymerization.

    PubMed

    Yang, Hongyan; Gottlieb, Paul; Wei, Hui; Bamford, Dennis H; Makeyev, Eugene V

    2003-09-30

    To continue the molecular characterization of RNA-dependent RNA polymerases of dsRNA bacteriophages (Cystoviridae), we purified and biochemically characterized the wild-type (wt) and a temperature-sensitive (ts) point mutant of the polymerase subunit (Pol) from bacteriophage phi12. Interestingly, initiation by both wt and the ts phi12 Pol was notably more sensitive to increased temperatures than the elongation step, the absolute value of the nonpermissive temperature being lower for the ts enzyme. Experiments with the Pol subunit of related cystovirus phi6 revealed a similar differential sensitivity of the initiation and elongation steps. This is consistent with the previous result showing that de novo initiation by RdRp from dengue virus is inhibited at elevated temperatures, whereas the elongation phase is relatively thermostable. Overall, these data suggest that de novo RNA-dependent RNA synthesis in many viral systems includes a specialized thermolabile state of the RdRp initiation complex.

  10. Extraordinary GU-rich single-strand RNA identified from SARS coronavirus contributes an excessive innate immune response.

    PubMed

    Li, Yan; Chen, Ming; Cao, Hongwei; Zhu, Yuanfeng; Zheng, Jiang; Zhou, Hong

    2013-02-01

    A dangerous cytokine storm occurs in the SARS involving in immune disorder, but many aspects of the pathogenetic mechanism remain obscure since its outbreak. To deeply reveal the interaction of host and SARS-CoV, based on the basic structural feature of pathogen-associated molecular pattern, we created a new bioinformatics method for searching potential pathogenic molecules and identified a set of SARS-CoV specific GU-rich ssRNA fragments with a high-density distribution in the genome. In vitro experiments, the result showed the representative SARS-CoV ssRNAs had powerful immunostimulatory activities to induce considerable level of pro-inflammatory cytokine TNF-a, IL-6 and IL-12 release via the TLR7 and TLR8, almost 2-fold higher than the strong stimulatory ssRNA40 that was found previously from other virus. Moreover, SARS-CoV ssRNA was able to cause acute lung injury in mice with a high mortality rate in vivo experiment. It suggests that SARS-CoV specific GU-rich ssRNA plays a very important role in the cytokine storm associated with a dysregulation of the innate immunity. This study not only presents new evidence about the immunopathologic damage caused by overactive inflammation during the SARS-CoV infection, but also provides a useful clue for a new therapeutic strategy. Copyright © 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  11. mRNA Cap Methyltransferase, RNMT-RAM, Promotes RNA Pol II-Dependent Transcription.

    PubMed

    Varshney, Dhaval; Lombardi, Olivia; Schweikert, Gabriele; Dunn, Sianadh; Suska, Olga; Cowling, Victoria H

    2018-05-01

    mRNA cap addition occurs early during RNA Pol II-dependent transcription, facilitating pre-mRNA processing and translation. We report that the mammalian mRNA cap methyltransferase, RNMT-RAM, promotes RNA Pol II transcription independent of mRNA capping and translation. In cells, sublethal suppression of RNMT-RAM reduces RNA Pol II occupancy, net mRNA synthesis, and pre-mRNA levels. Conversely, expression of RNMT-RAM increases transcription independent of cap methyltransferase activity. In isolated nuclei, recombinant RNMT-RAM stimulates transcriptional output; this requires the RAM RNA binding domain. RNMT-RAM interacts with nascent transcripts along their entire length and with transcription-associated factors including the RNA Pol II subunits SPT4, SPT6, and PAFc. Suppression of RNMT-RAM inhibits transcriptional markers including histone H2BK120 ubiquitination, H3K4 and H3K36 methylation, RNA Pol II CTD S5 and S2 phosphorylation, and PAFc recruitment. These findings suggest that multiple interactions among RNMT-RAM, RNA Pol II factors, and RNA along the transcription unit stimulate transcription. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  12. A mouse model for MERS coronavirus-induced acute respiratory distress syndrome.

    PubMed

    Cockrell, Adam S; Yount, Boyd L; Scobey, Trevor; Jensen, Kara; Douglas, Madeline; Beall, Anne; Tang, Xian-Chun; Marasco, Wayne A; Heise, Mark T; Baric, Ralph S

    2016-11-28

    Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel virus that emerged in 2012, causing acute respiratory distress syndrome (ARDS), severe pneumonia-like symptoms and multi-organ failure, with a case fatality rate of ∼36%. Limited clinical studies indicate that humans infected with MERS-CoV exhibit pathology consistent with the late stages of ARDS, which is reminiscent of the disease observed in patients infected with severe acute respiratory syndrome coronavirus. Models of MERS-CoV-induced severe respiratory disease have been difficult to achieve, and small-animal models traditionally used to investigate viral pathogenesis (mouse, hamster, guinea-pig and ferret) are naturally resistant to MERS-CoV. Therefore, we used CRISPR-Cas9 gene editing to modify the mouse genome to encode two amino acids (positions 288 and 330) that match the human sequence in the dipeptidyl peptidase 4 receptor, making mice susceptible to MERS-CoV infection and replication. Serial MERS-CoV passage in these engineered mice was then used to generate a mouse-adapted virus that replicated efficiently within the lungs and evoked symptoms indicative of severe ARDS, including decreased survival, extreme weight loss, decreased pulmonary function, pulmonary haemorrhage and pathological signs indicative of end-stage lung disease. Importantly, therapeutic countermeasures comprising MERS-CoV neutralizing antibody treatment or a MERS-CoV spike protein vaccine protected the engineered mice against MERS-CoV-induced ARDS.

  13. BLM helicase facilitates RNA polymerase I-mediated ribosomal RNA transcription

    PubMed Central

    Grierson, Patrick M.; Lillard, Kate; Behbehani, Gregory K.; Combs, Kelly A.; Bhattacharyya, Saumitri; Acharya, Samir; Groden, Joanna

    2012-01-01

    Bloom's syndrome (BS) is an autosomal recessive disorder that is invariably characterized by severe growth retardation and cancer predisposition. The Bloom's syndrome helicase (BLM), mutations of which lead to BS, localizes to promyelocytic leukemia protein bodies and to the nucleolus of the cell, the site of RNA polymerase I-mediated ribosomal RNA (rRNA) transcription. rRNA transcription is fundamental for ribosome biogenesis and therefore protein synthesis, cellular growth and proliferation; its inhibition limits cellular growth and proliferation as well as bodily growth. We report that nucleolar BLM facilitates RNA polymerase I-mediated rRNA transcription. Immunofluorescence studies demonstrate the dependance of BLM nucleolar localization upon ongoing RNA polymerase I-mediated rRNA transcription. In vivo protein co-immunoprecipitation demonstrates that BLM interacts with RPA194, a subunit of RNA polymerase I. 3H-uridine pulse-chase assays demonstrate that BLM expression is required for efficient rRNA transcription. In vitro helicase assays demonstrate that BLM unwinds GC-rich rDNA-like substrates that form in the nucleolus and normally inhibit progression of the RNA polymerase I transcription complex. These studies suggest that nucleolar BLM modulates rDNA structures in association with RNA polymerase I to facilitate RNA polymerase I-mediated rRNA transcription. Given the intricate relationship between rDNA metabolism and growth, our data may help in understanding the etiology of proportional dwarfism in BS. PMID:22106380

  14. BLM helicase facilitates RNA polymerase I-mediated ribosomal RNA transcription.

    PubMed

    Grierson, Patrick M; Lillard, Kate; Behbehani, Gregory K; Combs, Kelly A; Bhattacharyya, Saumitri; Acharya, Samir; Groden, Joanna

    2012-03-01

    Bloom's syndrome (BS) is an autosomal recessive disorder that is invariably characterized by severe growth retardation and cancer predisposition. The Bloom's syndrome helicase (BLM), mutations of which lead to BS, localizes to promyelocytic leukemia protein bodies and to the nucleolus of the cell, the site of RNA polymerase I-mediated ribosomal RNA (rRNA) transcription. rRNA transcription is fundamental for ribosome biogenesis and therefore protein synthesis, cellular growth and proliferation; its inhibition limits cellular growth and proliferation as well as bodily growth. We report that nucleolar BLM facilitates RNA polymerase I-mediated rRNA transcription. Immunofluorescence studies demonstrate the dependance of BLM nucleolar localization upon ongoing RNA polymerase I-mediated rRNA transcription. In vivo protein co-immunoprecipitation demonstrates that BLM interacts with RPA194, a subunit of RNA polymerase I. (3)H-uridine pulse-chase assays demonstrate that BLM expression is required for efficient rRNA transcription. In vitro helicase assays demonstrate that BLM unwinds GC-rich rDNA-like substrates that form in the nucleolus and normally inhibit progression of the RNA polymerase I transcription complex. These studies suggest that nucleolar BLM modulates rDNA structures in association with RNA polymerase I to facilitate RNA polymerase I-mediated rRNA transcription. Given the intricate relationship between rDNA metabolism and growth, our data may help in understanding the etiology of proportional dwarfism in BS.

  15. Role of RNase MRP in viral RNA degradation and RNA recombination.

    PubMed

    Jaag, Hannah M; Lu, Qiasheng; Schmitt, Mark E; Nagy, Peter D

    2011-01-01

    RNA degradation, together with RNA synthesis, controls the steady-state level of viral RNAs in infected cells. The endoribonucleolytic cleavage of viral RNA is important not only for viral RNA degradation but for RNA recombination as well, due to the participation of some RNA degradation products in the RNA recombination process. To identify host endoribonucleases involved in degradation of Tomato bushy stunt virus (TBSV) in a Saccharomyces cerevisiae model host, we tested eight known endoribonucleases. Here we report that downregulation of SNM1, encoding a component of the RNase MRP, and a temperature-sensitive mutation in the NME1 gene, coding for the RNA component of RNase MRP, lead to reduced production of the endoribonucleolytically cleaved TBSV RNA in yeast. We also show that the highly purified yeast RNase MRP cleaves the TBSV RNA in vitro, resulting in TBSV RNA degradation products similar in size to those observed in yeast cells. Knocking down the NME1 homolog in Nicotiana benthamiana also led to decreased production of the cleaved TBSV RNA, suggesting that in plants, RNase MRP is involved in TBSV RNA degradation. Altogether, this work suggests a role for the host endoribonuclease RNase MRP in viral RNA degradation and recombination.

  16. Severe Acute Respiratory Syndrome (SARS) Coronavirus ORF8 Protein Is Acquired from SARS-Related Coronavirus from Greater Horseshoe Bats through Recombination

    PubMed Central

    Lau, Susanna K. P.; Feng, Yun; Chen, Honglin; Luk, Hayes K. H.; Yang, Wei-Hong; Li, Kenneth S. M.; Zhang, Yu-Zhen; Huang, Yi; Song, Zhi-Zhong; Chow, Wang-Ngai; Fan, Rachel Y. Y.; Ahmed, Syed Shakeel; Yeung, Hazel C.; Lam, Carol S. F.; Cai, Jian-Piao; Wong, Samson S. Y.; Chan, Jasper F. W.; Yuen, Kwok-Yung

    2015-01-01

    ABSTRACT Despite the identification of horseshoe bats as the reservoir of severe acute respiratory syndrome (SARS)-related coronaviruses (SARSr-CoVs), the origin of SARS-CoV ORF8, which contains the 29-nucleotide signature deletion among human strains, remains obscure. Although two SARS-related Rhinolophus sinicus bat CoVs (SARSr-Rs-BatCoVs) previously detected in Chinese horseshoe bats (Rhinolophus sinicus) in Yunnan, RsSHC014 and Rs3367, possessed 95% genome identities to human and civet SARSr-CoVs, their ORF8 protein exhibited only 32.2 to 33% amino acid identities to that of human/civet SARSr-CoVs. To elucidate the origin of SARS-CoV ORF8, we sampled 348 bats of various species in Yunnan, among which diverse alphacoronaviruses and betacoronaviruses, including potentially novel CoVs, were identified, with some showing potential interspecies transmission. The genomes of two betacoronaviruses, SARSr-Rf-BatCoV YNLF_31C and YNLF_34C, from greater horseshoe bats (Rhinolophus ferrumequinum), possessed 93% nucleotide identities to human/civet SARSr-CoV genomes. Although these two betacoronaviruses displayed lower similarities than SARSr-Rs-BatCoV RsSHC014 and Rs3367 in S protein to civet SARSr-CoVs, their ORF8 proteins demonstrated exceptionally high (80.4 to 81.3%) amino acid identities to that of human/civet SARSr-CoVs, compared to SARSr-BatCoVs from other horseshoe bats (23.2 to 37.3%). Potential recombination events were identified around ORF8 between SARSr-Rf-BatCoVs and SARSr-Rs-BatCoVs, leading to the generation of civet SARSr-CoVs. The expression of ORF8 subgenomic mRNA suggested that the ORF8 protein may be functional in SARSr-Rf-BatCoVs. The high Ka/Ks ratio among human SARS-CoVs compared to that among SARSr-BatCoVs supported that ORF8 is under strong positive selection during animal-to-human transmission. Molecular clock analysis using ORF1ab showed that SARSr-Rf-BatCoV YNLF_31C and YNLF_34C diverged from civet/human SARSr-CoVs in approximately 1990. SARS

  17. Severe Acute Respiratory Syndrome (SARS) Coronavirus ORF8 Protein Is Acquired from SARS-Related Coronavirus from Greater Horseshoe Bats through Recombination.

    PubMed

    Lau, Susanna K P; Feng, Yun; Chen, Honglin; Luk, Hayes K H; Yang, Wei-Hong; Li, Kenneth S M; Zhang, Yu-Zhen; Huang, Yi; Song, Zhi-Zhong; Chow, Wang-Ngai; Fan, Rachel Y Y; Ahmed, Syed Shakeel; Yeung, Hazel C; Lam, Carol S F; Cai, Jian-Piao; Wong, Samson S Y; Chan, Jasper F W; Yuen, Kwok-Yung; Zhang, Hai-Lin; Woo, Patrick C Y

    2015-10-01

    Despite the identification of horseshoe bats as the reservoir of severe acute respiratory syndrome (SARS)-related coronaviruses (SARSr-CoVs), the origin of SARS-CoV ORF8, which contains the 29-nucleotide signature deletion among human strains, remains obscure. Although two SARS-related Rhinolophus sinicus bat CoVs (SARSr-Rs-BatCoVs) previously detected in Chinese horseshoe bats (Rhinolophus sinicus) in Yunnan, RsSHC014 and Rs3367, possessed 95% genome identities to human and civet SARSr-CoVs, their ORF8 protein exhibited only 32.2 to 33% amino acid identities to that of human/civet SARSr-CoVs. To elucidate the origin of SARS-CoV ORF8, we sampled 348 bats of various species in Yunnan, among which diverse alphacoronaviruses and betacoronaviruses, including potentially novel CoVs, were identified, with some showing potential interspecies transmission. The genomes of two betacoronaviruses, SARSr-Rf-BatCoV YNLF_31C and YNLF_34C, from greater horseshoe bats (Rhinolophus ferrumequinum), possessed 93% nucleotide identities to human/civet SARSr-CoV genomes. Although these two betacoronaviruses displayed lower similarities than SARSr-Rs-BatCoV RsSHC014 and Rs3367 in S protein to civet SARSr-CoVs, their ORF8 proteins demonstrated exceptionally high (80.4 to 81.3%) amino acid identities to that of human/civet SARSr-CoVs, compared to SARSr-BatCoVs from other horseshoe bats (23.2 to 37.3%). Potential recombination events were identified around ORF8 between SARSr-Rf-BatCoVs and SARSr-Rs-BatCoVs, leading to the generation of civet SARSr-CoVs. The expression of ORF8 subgenomic mRNA suggested that the ORF8 protein may be functional in SARSr-Rf-BatCoVs. The high Ka/Ks ratio among human SARS-CoVs compared to that among SARSr-BatCoVs supported that ORF8 is under strong positive selection during animal-to-human transmission. Molecular clock analysis using ORF1ab showed that SARSr-Rf-BatCoV YNLF_31C and YNLF_34C diverged from civet/human SARSr-CoVs in approximately 1990. SARS-CoV ORF8

  18. Suppression of Murine Retrovirus Polypeptide Termination: Effect of Amber Suppressor tRNA on the Cell-Free Translation of Rauscher Murine Leukemia Virus, Moloney Murine Leukemia Virus, and Moloney Murine Sarcoma Virus 124 RNA

    PubMed Central

    Murphy, Edwin C.; Wills, Norma; Arlinghaus, Ralph B.

    1980-01-01

    The effect of suppressor tRNA's on the cell-free translation of several leukemia and sarcoma virus RNAs was examined. Yeast amber suppressor tRNA (amber tRNA) enhanced the synthesis of the Rauscher murine leukemia virus and clone 1 Moloney murine leukemia virus Pr200gag-pol polypeptides by 10- to 45-fold, but at the same time depressed the synthesis of Rauscher murine leukemia virus Pr65gag and Moloney murine leukemia virus Pr63gag. Under suppressor-minus conditions, Moloney murine leukemia virus Pr70gag was present as a closely spaced doublet. Amber tRNA stimulated the synthesis of the “upper” Moloney murine leukemia virus Pr70gag polypeptide. Yeast ochre suppressor tRNA appeared to be ineffective. Quantitative analyses of the kinetics of viral precursor polypeptide accumulation in the presence of amber tRNA showed that during linear protein synthesis, the increase in accumulated Moloney murine leukemia virus Pr200gag-pol coincided closely with the molar loss of Pr63gag. Enhancement of Pr200gag-pol and Pr70gag by amber tRNA persisted in the presence of pactamycin, a drug which blocks the initiation of protein synthesis, thus arguing for the addition of amino acids to the C terminus of Pr63gag as the mechanism behind the amber tRNA effect. Moloney murine sarcoma virus 124 30S RNA was translated into four major polypeptides, Pr63gag, P42, P38, and P23. In the presence of amber tRNA, a new polypeptide, Pr67gag, appeared, whereas Pr63gag synthesis was decreased. Quantitative estimates indicated that for every 1 mol of Pr67gag which appeared, 1 mol of Pr63gag was lost. Images PMID:7373716

  19. Hospital Outbreak of Middle East Respiratory Syndrome Coronavirus

    PubMed Central

    Assiri, Abdullah; McGeer, Allison; Perl, Trish M.; Price, Connie S.; Al Rabeeah, Abdullah A.; Cummings, Derek A.T.; Alabdullatif, Zaki N.; Assad, Maher; Almulhim, Abdulmohsen; Makhdoom, Hatem; Madani, Hossam; Alhakeem, Rafat; Al-Tawfiq, Jaffar A.; Cotten, Matthew; Watson, Simon J.; Kellam, Paul; Zumla, Alimuddin I.; Memish, Ziad A.

    2013-01-01

    BACKGROUND In September 2012, the World Health Organization reported the first cases of pneumonia caused by the novel Middle East respiratory syndrome coronavirus (MERS-CoV). We describe a cluster of health care–acquired MERS-CoV infections. METHODS Medical records were reviewed for clinical and demographic information and determination of potential contacts and exposures. Case patients and contacts were interviewed. The incubation period and serial interval (the time between the successive onset of symptoms in a chain of transmission) were estimated. Viral RNA was sequenced. RESULTS Between April 1 and May 23, 2013, a total of 23 cases of MERS-CoV infection were reported in the eastern province of Saudi Arabia. Symptoms included fever in 20 patients (87%), cough in 20 (87%), shortness of breath in 11 (48%), and gastrointestinal symptoms in 8 (35%); 20 patients (87%) presented with abnormal chest radiographs. As of June 12, a total of 15 patients (65%) had died, 6 (26%) had recovered, and 2 (9%) remained hospitalized. The median incubation period was 5.2 days (95% confidence interval [CI], 1.9 to 14.7), and the serial interval was 7.6 days (95% CI, 2.5 to 23.1). A total of 21 of the 23 cases were acquired by person-to-person transmission in hemodialysis units, intensive care units, or in-patient units in three different health care facilities. Sequencing data from four isolates revealed a single monophyletic clade. Among 217 household contacts and more than 200 health care worker contacts whom we identified, MERS-CoV infection developed in 5 family members (3 with laboratory-confirmed cases) and in 2 health care workers (both with laboratory-confirmed cases). CONCLUSIONS Person-to-person transmission of MERS-CoV can occur in health care settings and may be associated with considerable morbidity. Surveillance and infection-control measures are critical to a global public health response. PMID:23782161

  20. SARS-like cluster of circulating bat coronavirus pose threat for human emergence

    PubMed Central

    Menachery, Vineet D.; Yount, Boyd L.; Debbink, Kari; Agnihothram, Sudhakar; Gralinski, Lisa E.; Plante, Jessica A.; Graham, Rachel L.; Scobey, Trevor; Ge, Xing-Yi; Donaldson, Eric F.; Randell, Scott H.; Lanzavecchia, Antonio; Marasco, Wayne A.; Shi, Zhengli-Li; Baric, Ralph S.

    2016-01-01

    The emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrome (MERS)-CoV underscores the threat of cross-species transmission events leading to outbreaks in humans. In this study, we examine the disease potential for SARS-like CoVs currently circulating in Chinese horseshoe bat populations. Utilizing the SARS-CoV infectious clone, we generated and characterized a chimeric virus expressing the spike of bat coronavirus SHC014 in a mouse adapted SARS-CoV backbone. The results indicate that group 2b viruses encoding the SHC014 spike in a wild type backbone can efficiently utilize multiple ACE2 receptor orthologs, replicate efficiently in primary human airway cells, and achieve in vitro titers equivalent to epidemic strains of SARS-CoV. Additionally, in vivo experiments demonstrate replication of the chimeric virus in mouse lung with notable pathogenesis. Evaluation of available SARS-based immune-therapeutic and prophylactic modalities revealed poor efficacy; both monoclonal antibody and vaccine approaches failed to neutralize and protect from CoVs utilizing the novel spike protein. Importantly, based on these findings, we synthetically rederived an infectious full length SHC014 recombinant virus and demonstrate robust viral replication both in vitro and in vivo. Together, the work highlights a continued risk of SARS-CoV reemergence from viruses currently circulating in bat populations. PMID:26552008

  1. Evaluation of a computer-assisted, kinetics-based enzyme-linked immunosorbent assay for detection of coronavirus antibodies in cats.

    PubMed Central

    Barlough, J E; Jacobson, R H; Downing, D R; Marcella, K L; Lynch, T J; Scott, F W

    1983-01-01

    A computer-assisted, kinetics-based enzyme-linked immunosorbent assay was adapted for the detection of coronavirus antibodies in feline serum. An alkaline antigen diluent (carbonate-bicarbonate buffer, pH 9.6) used in initial experiments produced diffuse, nonspecific color reactions in both viral and control antigen cuvettes which were correlated, paradoxically, with coronavirus antibody levels in test sera. These interfering reactions were minimized by use of lower-pH antigen diluents such as water and phosphate-buffered saline. Background kinetics-based enzyme-linked immunosorbent assay reactivity directed against a noncoronaviral component of antigen tissue culture fluids could then detected in numerous sera, particularly in samples with lower titers. Much of this reactivity was shown to be associated with bovine gamma globulins in cell culture fluid. It was not serum lot or species specific, since a variety of bovine serum lots as well as individual lots of serum from other mammalian and avian species reacted. Reactivity was markedly reduced when cells for antigen preparation were grown in gamma globulin-free bovine serum. Generation of corrected slope values from the kinetics-based enzyme-linked immunosorbent assay made it possible to correct for residual background reactivity in individual test sera and thus eliminate a potentially major source of false-positive reactions. Collectively, these studies indicated that the control of nonspecific reactivity in feline coronavirus serology is absolutely essential to obtain useful estimates of specific antibody responses. PMID:6300184

  2. Evaluation of a computer-assisted, kinetics-based enzyme-linked immunosorbent assay for detection of coronavirus antibodies in cats.

    PubMed

    Barlough, J E; Jacobson, R H; Downing, D R; Marcella, K L; Lynch, T J; Scott, F W

    1983-02-01

    A computer-assisted, kinetics-based enzyme-linked immunosorbent assay was adapted for the detection of coronavirus antibodies in feline serum. An alkaline antigen diluent (carbonate-bicarbonate buffer, pH 9.6) used in initial experiments produced diffuse, nonspecific color reactions in both viral and control antigen cuvettes which were correlated, paradoxically, with coronavirus antibody levels in test sera. These interfering reactions were minimized by use of lower-pH antigen diluents such as water and phosphate-buffered saline. Background kinetics-based enzyme-linked immunosorbent assay reactivity directed against a noncoronaviral component of antigen tissue culture fluids could then detected in numerous sera, particularly in samples with lower titers. Much of this reactivity was shown to be associated with bovine gamma globulins in cell culture fluid. It was not serum lot or species specific, since a variety of bovine serum lots as well as individual lots of serum from other mammalian and avian species reacted. Reactivity was markedly reduced when cells for antigen preparation were grown in gamma globulin-free bovine serum. Generation of corrected slope values from the kinetics-based enzyme-linked immunosorbent assay made it possible to correct for residual background reactivity in individual test sera and thus eliminate a potentially major source of false-positive reactions. Collectively, these studies indicated that the control of nonspecific reactivity in feline coronavirus serology is absolutely essential to obtain useful estimates of specific antibody responses.

  3. Functional expansion of human tRNA synthetases achieved by structural inventions

    PubMed Central

    Guo, Min; Schimmel, Paul; Yang, Xiang-Lei

    2010-01-01

    Known as an essential component of the translational apparatus, the aminoacyl-tRNA synthetase family catalyzes the first step reaction in protein synthesis, that is, to specifically attach each amino acid to its cognate tRNA. While preserving this essential role, tRNA synthetases developed other roles during evolution. Human tRNA synthetases, in particular, have diverse functions in different pathways involving angiogenesis, inflammation and apoptosis. The functional diversity is further illustrated in the association with various diseases through genetic mutations that do not affect aminoacylation or protein synthesis. Here we review the accumulated knowledge on how human tRNA synthetases used structural inventions to achieve functional expansions. PMID:19932696

  4. RNA polymerase pausing and nascent RNA structure formation are linked through clamp domain movement

    PubMed Central

    Hein, Pyae P.; Kolb, Kellie E.; Windgassen, Tricia; Bellecourt, Michael J.; Darst, Seth A.; Mooney, Rachel A.; Landick, Robert

    2014-01-01

    The rates of RNA synthesis and nascent RNA folding into biologically active structures are linked via pausing by RNA polymerase (RNAP). Structures that form within the RNA exit channel can increase pausing by interacting with bacterial RNAP or decrease pausing by preventing backtracking. Conversely, pausing is required for proper folding of some RNAs. Opening of the RNAP clamp domain is proposed to mediate some effects of nascent RNA structures. However, the connections among RNA structure formation, clamp movement, and catalytic activity remain uncertain. We assayed exit-channel structure formation in Escherichia coli RNAP together with disulfide crosslinks that favor closed or open clamp conformations and found that clamp position directly influences RNA structure formation and catalytic activity. We report that exit-channel RNA structures slow pause escape by favoring clamp opening and through interactions with the flap that slow translocation. PMID:25108353

  5. Lactoferricin B inhibits bacterial macromolecular synthesis in Escherichia coli and Bacillus subtilis.

    PubMed

    Ulvatne, Hilde; Samuelsen, Ørjan; Haukland, Hanne H; Krämer, Manuela; Vorland, Lars H

    2004-08-15

    Most antimicrobial peptides have an amphipathic, cationic structure, and an effect on the cytoplasmic membrane of susceptible bacteria has been postulated as the main mode of action. Other mechanisms have been reported, including inhibition of cellular functions by binding to DNA, RNA and proteins, and the inhibition of DNA and/or protein synthesis. Lactoferricin B (Lfcin B), a cationic peptide derived from bovine lactoferrin, exerts slow inhibitory and bactericidal activity and does not lyse susceptible bacteria, indicating a possible intracellular target. In the present study incorporation of radioactive precursors into DNA, RNA and proteins was used to demonstrate effects of Lfcin B on macromolecular synthesis in bacteria. In Escherichia coli UC 6782, Lfcin B induces an initial increase in protein and RNA synthesis and a decrease in DNA synthesis. After 10 min, the DNA-synthesis increases while protein and RNA-synthesis decreases significantly. In Bacillus subtilis, however, all synthesis of macromolecules is inhibited for at least 20 min. After 20 min RNA-synthesis increases. The results presented here show that Lfcin B at concentrations not sufficient to kill bacterial cells inhibits incorporation of radioactive precursors into macromolecules in both Gram-positive and Gram-negative bacteria.

  6. First Case of Systemic Coronavirus Infection in a Domestic Ferret (Mustela putorius furo) in Peru.

    PubMed

    Lescano, J; Quevedo, M; Gonzales-Viera, O; Luna, L; Keel, M K; Gregori, F

    2015-12-01

    A domestic ferret from Lima, Peru, died after ten days of non-specific clinical signs. Based on pathology, immunohistochemistry and molecular analysis, ferret systemic coronavirus (FRSCV)-associated disease was diagnosed for the first time in South America. This report highlights the potential spread of pathogens by the international pet trade. © 2015 Blackwell Verlag GmbH.

  7. Surveillance and Testing for Middle East Respiratory Syndrome Coronavirus, Saudi Arabia, April 2015-February 2016.

    PubMed

    Saeed, Abdulaziz A Bin; Abedi, Glen R; Alzahrani, Abdullah G; Salameh, Iyad; Abdirizak, Fatima; Alhakeem, Raafat; Algarni, Homoud; El Nil, Osman A; Mohammed, Mutaz; Assiri, Abdullah M; Alabdely, Hail M; Watson, John T; Gerber, Susan I

    2017-04-01

    Saudi Arabia has reported >80% of the Middle East respiratory syndrome coronavirus (MERS-CoV) cases worldwide. During April 2015-February 2016, Saudi Arabia identified and tested 57,363 persons (18.4/10,000 residents) with suspected MERS-CoV infection; 384 (0.7%) tested positive. Robust, extensive, and timely surveillance is critical for limiting virus transmission.

  8. Effects of inhibitors on early protein, RNA, and lipid synthesis in germinating vesicular-arbuscular mycorrhizal fungal spores of Glomus caledonium.

    PubMed

    Beilby, J P

    1983-05-01

    The incorporation of isotopically labelled precursors, [1-14C]leucine, [2-14C]uracil and [1-14C]acetate, by germinating spores of the vesicular-arbuscular mycorrhizal fungus Glomus caledonium was investigated after prior incubation with several metabolic inhibitors. Inhibition of isotope incorporation was greatest with ethidium bromide and cycloheximide and least with chloramphenicol and actinomycin D. The incorporation of [1-14C]leucine into protein was reduced by 92% within 60 min of incubation in either ethidium bromide at 5 micrograms/mL or cycloheximide at 100 micrograms/mL. For these studies time zero was coincident with dry quiescent spores being first wet. Lipid synthesis during germination of the spores was detected at 120 min by following the incorporation of [1-14C]acetate. At 51 h, incorporation was greater in the triacylglycerides and diacylglycerides than in the free sterols, phospholipids, or free fatty acid. Spores exposed to cycloheximide for 60 min after imbibition showed very little phospholipid synthesis and no free fatty acid synthesis. The synthesis of RNA after spore imbibition is also discussed.

  9. Toll-Like Receptor 3 Signaling via TRIF Contributes to a Protective Innate Immune Response to Severe Acute Respiratory Syndrome Coronavirus Infection

    PubMed Central

    Totura, Allison L.; Whitmore, Alan; Agnihothram, Sudhakar; Schäfer, Alexandra; Katze, Michael G.; Heise, Mark T.

    2015-01-01

    ABSTRACT Toll-like receptors (TLRs) are sensors that recognize molecular patterns from viruses, bacteria, and fungi to initiate innate immune responses to invading pathogens. The emergence of highly pathogenic coronaviruses severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) is a concern for global public health, as there is a lack of efficacious vaccine platforms and antiviral therapeutic strategies. Previously, it was shown that MyD88, an adaptor protein necessary for signaling by multiple TLRs, is a required component of the innate immune response to mouse-adapted SARS-CoV infection in vivo. Here, we demonstrate that TLR3−/−, TLR4−/−, and TRAM−/− mice are more susceptible to SARS-CoV than wild-type mice but experience only transient weight loss with no mortality in response to infection. In contrast, mice deficient in the TLR3/TLR4 adaptor TRIF are highly susceptible to SARS-CoV infection, showing increased weight loss, mortality, reduced lung function, increased lung pathology, and higher viral titers. Distinct alterations in inflammation were present in TRIF−/− mice infected with SARS-CoV, including excess infiltration of neutrophils and inflammatory cell types that correlate with increased pathology of other known causes of acute respiratory distress syndrome (ARDS), including influenza virus infections. Aberrant proinflammatory cytokine, chemokine, and interferon-stimulated gene (ISG) signaling programs were also noted following infection of TRIF−/− mice that were similar to those seen in human patients with poor disease outcome following SARS-CoV or MERS-CoV infection. These findings highlight the importance of TLR adaptor signaling in generating a balanced protective innate immune response to highly pathogenic coronavirus infections. PMID:26015500

  10. The effect of ethionine on ribonucleic acid synthesis in rat liver.

    PubMed Central

    Swann, P F

    1975-01-01

    1. By 1h after administration of ethionine to the female rat the appearance of newly synthesized 18SrRNA in the cytoplasm is completely inhibited. This is not caused by inhibition of RNA synthesis, for the synthesis of the large ribosomal precursor RNA (45S) and of tRNA continues. Cleavage of 45S RNA to 32S RNA also occurs, but there was no evidence for the accumulation of mature or immature rRNA in the nucleus. 2. The effect of ethionine on the maturation of rRNA was not mimicked by an inhibitor of protein synthesis (cycloheximide) or an inhibitor of polyamine synthesis [methylglyoxal bis(guanylhydrazone)]. 3. Unlike the ethionine-induced inhibition of protein synthesis, this effect was not prevented by concurrent administration of inosine. A similar effect could be induced in HeLa cells by incubation for 1h in a medium lacking methionine. The ATP concentration in these cells was normal. From these two observations it was concluded that the effect of etionine on rRNA maturation is not caused by an ethionine-induced lack of ATP. It is suggested that ethionine, by lowering the hepatic concentration of S-adenosylmethionine, prevents methylation of the ribosomal precursor. The methylation is essential for the correct maturation of the molecule; without methylation complete degradation occurs. PMID:1212195

  11. Global epidemiology of non-influenza RNA respiratory viruses: data gaps and a growing need for surveillance.

    PubMed

    Tang, Julian W; Lam, Tommy T; Zaraket, Hassan; Lipkin, W Ian; Drews, Steven J; Hatchette, Todd F; Heraud, Jean-Michel; Koopmans, Marion P

    2017-10-01

    Together with influenza, the non-influenza RNA respiratory viruses (NIRVs), which include respiratory syncytial virus, parainfluenza viruses, coronavirus, rhinovirus, and human metapneumovirus, represent a considerable global health burden, as recognised by WHO's Battle against Respiratory Viruses initiative. By contrast with influenza viruses, little is known about the contemporaneous global diversity of these viruses, and the relevance of such for development of pharmaceutical interventions. Although far less advanced than for influenza, antiviral drugs and vaccines are in different stages of development for several of these viruses, but no interventions have been licensed. This scarcity of global genetic data represents a substantial knowledge gap and impediment to the eventual licensing of new antiviral drugs and vaccines for NIRVs. Enhanced genetic surveillance will assist and boost research and development into new antiviral drugs and vaccines for these viruses. Additionally, understanding the global diversity of respiratory viruses is also part of emerging disease preparedness, because non-human coronaviruses and paramyxoviruses have been listed as priority concerns in a recent WHO research and development blueprint initiative for emerging infectious diseases. In this Personal View, we explain further the rationale for expanding the genetic database of NIRVs and emphasise the need for greater investment in this area of research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Amiloride inhibits the initiation of Coxsackievirus and poliovirus RNA replication by inhibiting VPg uridylylation.

    PubMed

    Ogram, Sushma A; Boone, Christopher D; McKenna, Robert; Flanegan, James B

    2014-09-01

    The mechanism of amiloride inhibition of Coxsackievirus B3 (CVB3) and poliovirus type 1 (PV1) RNA replication was investigated using membrane-associated RNA replication complexes. Amiloride was shown to inhibit viral RNA replication and VPgpUpU synthesis. However, the drug had no effect on polymerase elongation activity during either (-) strand or (+) strand synthesis. These findings indicated that amiloride inhibited the initiation of RNA synthesis by inhibiting VPg uridylylation. In addition, in silico binding studies showed that amiloride docks in the VPg binding site on the back of the viral RNA polymerase, 3D(pol). Since VPg binding at this site on PV1 3D(pol) was previously shown to be required for VPg uridylylation, our results suggest that amiloride inhibits VPg binding to 3D(pol). In summary, our findings are consistent with a model in which amiloride inhibits VPgpUpU synthesis and viral RNA replication by competing with VPg for binding to 3D(pol). Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Quantitative identification of proteins that influence miRNA biogenesis by RNA pull-down-SILAC mass spectrometry (RP-SMS).

    PubMed

    Choudhury, Nila Roy; Michlewski, Gracjan

    2018-06-08

    RNA-binding proteins mediate and control gene expression. As some examples, they regulate pre-mRNA synthesis and processing; mRNA localisation, translation and decay; and microRNA (miRNA) biogenesis and function. Here, we present a detailed protocol for RNA pull-down coupled to stable isotope labelling by amino acids in cell culture (SILAC) mass spectrometry (RP-SMS) that enables quantitative, fast and specific detection of RNA-binding proteins that regulate miRNA biogenesis. In general, this method allows for the identification of RNA-protein complexes formed using in vitro or chemically synthesized RNAs and protein extracts derived from cultured cells. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Alternative bases in the RNA world: the prebiotic synthesis of urazole and its ribosides

    NASA Technical Reports Server (NTRS)

    Kolb, V. M.; Dworkin, J. P.; Miller, S. L.

    1994-01-01

    Urazole is a five-membered heterocyclic compound which is isosteric with uracil's hydrogen-bonding segment. Urazole reacts spontaneoulsy with ribose (and other aldoses) to give a mixture of four ribosides: alpha and beta pyranosides and furanosides. This reaction occurs in aqueous solution at mild temperatures. Thermodynamic and kinetic parameters for the reaction of urazole with ribose were determined. In contrast, uracil is completely unreactive with ribose under these conditions. Urazole's unusual reactivity is ascribed to the hydrazine portion of the molecule. Urazole can be synthesized from biuret and hydrazine under prebiotic conditions. The prebiotic synthesis of guanazole, which is isosteric in part to diaminopyrimidine and cytosine, is accomplished from dicyandiamide and hydrazine. Kinetic parameters for both prebiotic reactions were measured. Urazole and guanazole are transparent in the UV, which would be a favorable property in the absence of an ozone layer on the early Earth. Urazole makes hydrogen bonds with adenine in DMSO similar to those of uracil, as established by H NMR. All of these properties make urazole an attractive potential precursor to uracil and guanazole a potential precursor to cytosine in the RNA or pre-RNA world.

  15. In vivo effects of ecdysterone on puff formation, and RNA and protein synthesis in the salivary glands of Rhynchosciara americana.

    PubMed

    Alvarenga, C A; Winter, C E; Stocker, A J; Pueyo, M T; Lara, F J

    1991-01-01

    1. Fourth-instar larvae of Rhynchosciara americana were injected with the insect molting hormone, ecdysterone, giving final hemolymph concentrations from 4.46 to 223 microM. 2. Induction of the DNA puff, B2b, in the proximal (S1) region of the salivary glands of Rhynchosciara americana by 22.6 microM ecdysterone, was accompanied by the production of an mRNA and a polypeptide with the same characteristics as B2b products produced during normal development. This mRNA and polypeptide were restricted to the proximal region of the gland, as is the B2b puff. 3. Synthesis of other poly(A)+RNAs was also stimulated in S1 by ecdysterone, and other puffs that appear during normal development were induced. However, rRNA production in S1 goes through a pattern of inhibition, followed by recovery when B2b is puffed, and subsequent inhibition. 4. Low molecular weight RNA, with a peak in the region of 4S, is stimulated after ecdysterone administration.

  16. Follow-up of Contacts of Middle East Respiratory Syndrome Coronavirus-Infected Returning Travelers, the Netherlands, 2014.

    PubMed

    Mollers, Madelief; Jonges, Marcel; Pas, Suzan D; van der Eijk, Annemiek A; Dirksen, Kees; Jansen, Casper; Gelinck, Luc B S; Leyten, Eliane M S; Thurkow, Ingrid; Groeneveld, Paul H P; van Gageldonk-Lafeber, Arianne B; Koopmans, Marion P; Timen, Aura

    2015-09-01

    Notification of 2 imported cases of infection with Middle East respiratory syndrome coronavirus in the Netherlands triggered comprehensive monitoring of contacts. Observed low rates of virus transmission and the psychological effect of contact monitoring indicate that thoughtful assessment of close contacts is prudent and must be guided by clinical and epidemiologic risk factors.

  17. Synthesizing topological structures containing RNA

    NASA Astrophysics Data System (ADS)

    Liu, Di; Shao, Yaming; Chen, Gang; Tse-Dinh, Yuk-Ching; Piccirilli, Joseph A.; Weizmann, Yossi

    2017-03-01

    Though knotting and entanglement have been observed in DNA and proteins, their existence in RNA remains an enigma. Synthetic RNA topological structures are significant for understanding the physical and biological properties pertaining to RNA topology, and these properties in turn could facilitate identifying naturally occurring topologically nontrivial RNA molecules. Here we show that topological structures containing single-stranded RNA (ssRNA) free of strong base pairing interactions can be created either by configuring RNA-DNA hybrid four-way junctions or by template-directed synthesis with a single-stranded DNA (ssDNA) topological structure. By using a constructed ssRNA knot as a highly sensitive topological probe, we find that Escherichia coli DNA topoisomerase I has low RNA topoisomerase activity and that the R173A point mutation abolishes the unknotting activity for ssRNA, but not for ssDNA. Furthermore, we discover the topological inhibition of reverse transcription (RT) and obtain different RT-PCR patterns for an ssRNA knot and circle of the same sequence.

  18. Sorting of progeny coronavirus from condensed secretory proteins at the exit from the trans-Golgi network of AtT20 cells.

    PubMed

    Tooze, J; Tooze, S A; Fuller, S D

    1987-09-01

    Murine hepatitis virus (strain A59), (MHV-A59) is a coronavirus that buds into pre-Golgi compartments and then exploits the exocytic pathway of the host cell to reach the exterior. The fibroblastic cells in which replication of this virus is usually studied have only a constitutive exocytic pathway that the virus uses. MHV-A59 also infects, albeit inefficiently, AtT20 cells, murine pituitary tumor cells with a regulated as well as a constitutive exocytic pathway. Here we examine AtT20 cells at early times after the infection, when the Golgi apparatus retains its morphological and biochemical integrity. We observe that progeny coronavirus and secretory protein destined for the secretory granules of the regulated exocytic pathway traverse the same Golgi stacks and accumulate in the trans-Golgi network. Their pathways diverge at this site, the condensed secretory proteins including the ACTH going to the secretory granules and the coronavirus to post-Golgi transport vesicles devoid of ACTH. On very rare occasions there is missorting such that aggregates of condensed secretory proteins and viruses occur together in post-Golgi vesicles. We conclude that the constitutive and regulated exocytic pathways, identified respectively by the progeny virions and the secretory protein ACTH, diverge at the exit from the trans-Golgi network.

  19. A study of the dimer formation of Rous sarcoma virus RNA and of its effect on viral protein synthesis in vitro.

    PubMed

    Bieth, E; Gabus, C; Darlix, J L

    1990-01-11

    The genetic material of all retroviruses examined so far is an RNA dimer where two identical RNA subunits are joined at their 5' ends by a structure named dimer linkage structure (DLS). Since the precise location and structure of the DLS as well as the mechanism and role(s) of RNA dimerization remain unclear, we analysed the dimerization process of Rous sarcoma virus (RSV) RNA. For this purpose we set up an in vitro model for RSV RNA dimerization. Using this model RSV RNA was shown to form dimeric molecules and this dimerization process was greatly activated by nucleocapsid protein (NCp12) of RSV. Furthermore, RSV RNA dimerization was performed in the presence of complementary 5'32P-DNA oligomers in order to probe the monomer and dimer forms of RSV RNA. Data indicated that the DLS of RSV RNA probably maps between positions 544-564 from the 5' end. In an attempt to define sequences needed for the dimerization of RSV RNA, deletion mutageneses were generated in the 5' 600 nt. The results showed that the dimer promoting sequences probably are located within positions 208-270 and 400-600 from the 5' end and hence possibly encompassing the cis-acting elements needed for the specific encapsidation of RSV genomic RNA. Also it is reported that synthesis of the polyprotein precursor Pr76gag is inhibited upon dimerization of RSV RNA. These results suggest that dimerization and encapsidation of genome length RSV RNA might be linked in the course of virion formation since they appear to be under the control of the same cis elements, E and DLS, and the trans-acting factor nucleocapsid protein NCp12.

  20. RNase-Resistant Virus-Like Particles Containing Long Chimeric RNA Sequences Produced by Two-Plasmid Coexpression System▿

    PubMed Central

    Wei, Yuxiang; Yang, Changmei; Wei, Baojun; Huang, Jie; Wang, Lunan; Meng, Shuang; Zhang, Rui; Li, Jinming

    2008-01-01

    RNase-resistant, noninfectious virus-like particles containing exogenous RNA sequences (armored RNA) are good candidates as RNA controls and standards in RNA virus detection. However, the length of RNA packaged in the virus-like particles with high efficiency is usually less than 500 bases. In this study, we describe a method for producing armored L-RNA. Armored L-RNA is a complex of MS2 bacteriophage coat protein and RNA produced in Escherichia coli by the induction of a two-plasmid coexpression system in which the coat protein and maturase are expressed from one plasmid and the target RNA sequence with modified MS2 stem-loop (pac site) is transcribed from another plasmid. A 3V armored L-RNA of 2,248 bases containing six gene fragments—hepatitis C virus, severe acute respiratory syndrome coronavirus (SARS-CoV1, SARS-CoV2, and SARS-CoV3), avian influenza virus matrix gene (M300), and H5N1 avian influenza virus (HA300)—was successfully expressed by the two-plasmid coexpression system and was demonstrated to have all of the characteristics of armored RNA. We evaluated the 3V armored L-RNA as a calibrator for multiple virus assays. We used the WHO International Standard for HCV RNA (NIBSC 96/790) to calibrate the chimeric armored L-RNA, which was diluted by 10-fold serial dilutions to obtain samples containing 106 to 102 copies. In conclusion, the approach we used for armored L-RNA preparation is practical and could reduce the labor and cost of quality control in multiplex RNA virus assays. Furthermore, we can assign the chimeric armored RNA with an international unit for quantitative detection. PMID:18305135

  1. HYBRIDIZATION PROPERTIES OF DNA SEQUENCES DIRECTING THE SYNTHESIS OF MESSENGER RNA AND HETEROGENEOUS NUCLEAR RNA

    PubMed Central

    Greenberg, Jay R.; Perry, Robert P.

    1971-01-01

    The relationship of the DNA sequences from which polyribosomal messenger RNA (mRNA) and heterogeneous nuclear RNA (NRNA) of mouse L cells are transcribed was investigated by means of hybridization kinetics and thermal denaturation of the hybrids. Hybridization was performed in formamide solutions at DNA excess. Under these conditions most of the hybridizing mRNA and NRNA react at values of Dot (DNA concentration multiplied by time) expected for RNA transcribed from the nonrepeated or rarely repeated fraction of the genome. However, a fraction of both mRNA and NRNA hybridize at values of Dot about 10,000 times lower, and therefore must be transcribed from highly redundant DNA sequences. The fraction of NRNA hybridizing to highly repeated sequences is about 1.7 times greater than the corresponding fraction of mRNA. The hybrids formed by the rapidly reacting fractions of both NRNA and mRNA melt over a narrow temperature range with a midpoint about 11°C below that of native L cell DNA. This indicates that these hybrids consist of partially complementary sequences with approximately 11% mismatching of bases. Hybrids formed by the slowly reacting fraction of NRNA melt within 4°–6°C of native DNA, indicating very little, if any, mismatching of bases. Hybrids of the slowly reacting components of mRNA, formed under conditions of sufficiently low RNA input, have a high thermal stability, similar to that observed for hybrids of the slowly reacting NRNA component. However, when higher inputs of mRNA are used, hybrids are formed which have a strikingly lower thermal stability. This observation can be explained by assuming that there is sufficient similarity among the relatively rare DNA sequences coding for mRNA so that under hybridization conditions, in which these DNA sequences are not truly in excess, reversible hybrids exhibiting a considerable amount of mispairing are formed. The fact that a comparable phenomenon has not been observed for NRNA may mean that there is

  2. Genomic Analysis of 15 Human Coronaviruses OC43 (HCoV-OC43s) Circulating in France from 2001 to 2013 Reveals a High Intra-Specific Diversity with New Recombinant Genotypes

    PubMed Central

    Kin, Nathalie; Miszczak, Fabien; Lin, Wei; Ar Gouilh, Meriadeg; Vabret, Astrid

    2015-01-01

    Human coronavirus OC43 (HCoV-OC43) is one of five currently circulating human coronaviruses responsible for respiratory infections. Like all coronaviruses, it is characterized by its genome’s high plasticity. The objectives of the current study were to detect genetically distinct genotypes and eventually recombinant genotypes in samples collected in Lower Normandy between 2001 and 2013. To this end, we sequenced complete nsp12, S, and N genes of 15 molecular isolates of HCoV-OC43 from clinical samples and compared them to available data from the USA, Belgium, and Hong-Kong. A new cluster E was invariably detected from nsp12, S, and N data while the analysis of nsp12 and N genes revealed the existence of new F and G clusters respectively. The association of these different clusters of genes in our specimens led to the description of thirteen genetically distinct genotypes, among which eight recombinant viruses were discovered. Identification of these recombinant viruses, together with temporal analysis and tMRCA estimation, provides important information for understanding the dynamics of the evolution of these epidemic coronaviruses. PMID:26008694

  3. The effects of Nigella sativa (Ns), Anthemis hyalina (Ah) and Citrus sinensis (Cs) extracts on the replication of coronavirus and the expression of TRP genes family.

    PubMed

    Ulasli, Mustafa; Gurses, Serdar A; Bayraktar, Recep; Yumrutas, Onder; Oztuzcu, Serdar; Igci, Mehri; Igci, Yusuf Ziya; Cakmak, Ecir Ali; Arslan, Ahmet

    2014-03-01

    Extracts of Anthemis hyalina (Ah), Nigella sativa (Ns) and peels of Citrus sinensis (Cs) have been used as folk medicine to fight antimicrobial diseases. To evaluate the effect of extracts of Ah, Ns and Cs on the replication of coronavirus (CoV) and on the expression of TRP genes during coronavirus infection, HeLa-CEACAM1a (HeLa-epithelial carcinoembryonic antigen-related cell adhesion molecule 1a) cells were inoculated with MHV-A59 (mouse hepatitis virus-A59) at moi of 30. 1/50 dilution of the extracts was found to be the safe active dose. ELISA kits were used to detect the human IL-8 levels. Total RNA was isolated from the infected cells and cDNA was synthesized. Fluidigm Dynamic Array nanofluidic chip 96.96 was used to analyze the mRNA expression of 21 TRP genes and two control genes. Data was analyzed using the BioMark digital array software. Determinations of relative gene expression values were carried out by using the 2(-∆∆Ct) method (normalized threshold cycle (Ct) value of sample minus normalized Ct value of control). TCID50/ml (tissue culture infectious dose that will produce cytopathic effect in 50% of the inoculated tissue culture cells) was found for treatments to determine the viral loads. The inflammatory cytokine IL-8 level was found to increase for both 24 and 48 h time points following Ns extract treatment. TRPA1, TRPC4, TRPM6, TRPM7, TRPM8 and TRPV4 were the genes which expression levels changed significantly after Ah, Ns or Cs extract treatments. The virus load decreased when any of the Ah, Ns or Cs extracts was added to the CoV infected cells with Ah extract treatment leading to undetectable virus load for both 6 and 8 hpi. Although all the extract treatments had an effect on IL-8 secretion, TRP gene expression and virus load after CoV infection, it was the Ah extract treatment that showed the biggest difference in virus load. Therefore Ah extract is the best candidate in our hands that contains potential treatment molecule(s).

  4. Expression of Functional Influenza Virus RNA Polymerase in the Methylotrophic Yeast Pichia pastoris

    PubMed Central

    Hwang, Jung-Shan; Yamada, Kazunori; Honda, Ayae; Nakade, Kohji; Ishihama, Akira

    2000-01-01

    Influenza virus RNA polymerase with the subunit composition PB1-PB2-PA is a multifunctional enzyme with the activities of both synthesis and cleavage of RNA and is involved in both transcription and replication of the viral genome. In order to produce large amounts of the functional viral RNA polymerase sufficient for analysis of its structure-function relationships, the cDNAs for RNA segments 1, 2, and 3 of influenza virus A/PR/8, each under independent control of the alcohol oxidase gene promoter, were integrated into the chromosome of the methylotrophic yeast Pichia pastoris. Simultaneous expression of all three P proteins in the yeast P. pastoris was achieved by the addition of methanol. To purify the P protein complexes, a sequence coding for a histidine tag was added to the PB2 protein gene at its N terminus. Starting from the induced P. pastoris cell lysate, we partially purified a 3P complex by Ni2+-agarose affinity column chromatography. The 3P complex showed influenza virus model RNA-directed and ApG-primed RNA synthesis in vitro but was virtually inactive without addition of template or primer. The kinetic properties of model template-directed RNA synthesis and the requirements for template sequence were analyzed using the 3P complex. Furthermore, the 3P complex showed capped RNA-primed RNA synthesis. Thus, we conclude that functional influenza virus RNA polymerase with the catalytic properties of a transcriptase is formed in the methylotrophic yeast P. pastoris. PMID:10756019

  5. Identification of Diverse Alphacoronaviruses and Genomic Characterization of a Novel Severe Acute Respiratory Syndrome-Like Coronavirus from Bats in China

    PubMed Central

    He, Biao; Zhang, Yuzhen; Xu, Lin; Yang, Weihong; Yang, Fanli; Feng, Yun; Xia, Lele; Zhou, Jihua; Zhen, Weibin; Feng, Ye; Guo, Huancheng

    2014-01-01

    ABSTRACT Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been identified in bats in China, Europe, and Africa, most have a genetic organization significantly distinct from human/civet SARS CoVs in the receptor-binding domain (RBD), which mediates receptor binding and determines the host spectrum, resulting in their failure to cause human infections and making them unlikely progenitors of human/civet SARS CoVs. Here, a viral metagenomic analysis of 268 bat rectal swabs collected from four counties in Yunnan Province has identified hundreds of sequences relating to alpha- and betacoronaviruses. Phylogenetic analysis based on a conserved region of the RNA-dependent RNA polymerase gene revealed that alphacoronaviruses had diversities with some obvious differences from those reported previously. Full genomic analysis of a new SARS-like CoV from Baoshan (LYRa11) showed that it was 29,805 nucleotides (nt) in length with 13 open reading frames (ORFs), sharing 91% nucleotide identity with human/civet SARS CoVs and the most recently reported SARS-like CoV Rs3367, while sharing 89% with other bat SARS-like CoVs. Notably, it showed the highest sequence identity with the S gene of SARS CoVs and Rs3367, especially in the RBD region. Antigenic analysis showed that the S1 domain of LYRa11 could be efficiently recognized by SARS-convalescent human serum, indicating that LYRa11 is a novel virus antigenically close to SARS CoV. Recombination analyses indicate that LYRa11 is likely a recombinant descended from parental lineages that had evolved into a number of bat SARS-like CoVs. IMPORTANCE Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been discovered in bats worldwide, there are significant different genic structures, particularly in the S1 domain, which are responsible for host tropism determination, between bat SARS-like CoVs and human SARS CoVs, indicating that most reported bat SARS-like CoVs are

  6. Central ions and lateral asparagine/glutamine zippers stabilize the post-fusion hairpin conformation of the SARS coronavirus spike glycoprotein

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duquerroy, Stephane; Vigouroux, Armelle; Rottier, Peter J.M.

    2005-05-10

    The coronavirus spike glycoprotein is a class I membrane fusion protein with two characteristic heptad repeat regions (HR1 and HR2) in its ectodomain. Here, we report the X-ray structure of a previously characterized HR1/HR2 complex of the severe acute respiratory syndrome coronavirus spike protein. As expected, the HR1 and HR2 segments are organized in antiparallel orientations within a rod-like molecule. The HR1 helices form an exceptionally long (120 A) internal coiled coil stabilized by hydrophobic and polar interactions. A striking arrangement of conserved asparagine and glutamine residues of HR1 propagates from two central chloride ions, providing hydrogen-bonding 'zippers' that stronglymore » constrain the path of the HR2 main chain, forcing it to adopt an extended conformation at either end of a short HR2 {alpha}-helix.« less

  7. Discovery of a rich gene pool of bat SARS-related coronaviruses provides new insights into the origin of SARS coronavirus.

    PubMed

    Hu, Ben; Zeng, Lei-Ping; Yang, Xing-Lou; Ge, Xing-Yi; Zhang, Wei; Li, Bei; Xie, Jia-Zheng; Shen, Xu-Rui; Zhang, Yun-Zhi; Wang, Ning; Luo, Dong-Sheng; Zheng, Xiao-Shuang; Wang, Mei-Niang; Daszak, Peter; Wang, Lin-Fa; Cui, Jie; Shi, Zheng-Li

    2017-11-01

    A large number of SARS-related coronaviruses (SARSr-CoV) have been detected in horseshoe bats since 2005 in different areas of China. However, these bat SARSr-CoVs show sequence differences from SARS coronavirus (SARS-CoV) in different genes (S, ORF8, ORF3, etc) and are considered unlikely to represent the direct progenitor of SARS-CoV. Herein, we report the findings of our 5-year surveillance of SARSr-CoVs in a cave inhabited by multiple species of horseshoe bats in Yunnan Province, China. The full-length genomes of 11 newly discovered SARSr-CoV strains, together with our previous findings, reveals that the SARSr-CoVs circulating in this single location are highly diverse in the S gene, ORF3 and ORF8. Importantly, strains with high genetic similarity to SARS-CoV in the hypervariable N-terminal domain (NTD) and receptor-binding domain (RBD) of the S1 gene, the ORF3 and ORF8 region, respectively, were all discovered in this cave. In addition, we report the first discovery of bat SARSr-CoVs highly similar to human SARS-CoV in ORF3b and in the split ORF8a and 8b. Moreover, SARSr-CoV strains from this cave were more closely related to SARS-CoV in the non-structural protein genes ORF1a and 1b compared with those detected elsewhere. Recombination analysis shows evidence of frequent recombination events within the S gene and around the ORF8 between these SARSr-CoVs. We hypothesize that the direct progenitor of SARS-CoV may have originated after sequential recombination events between the precursors of these SARSr-CoVs. Cell entry studies demonstrated that three newly identified SARSr-CoVs with different S protein sequences are all able to use human ACE2 as the receptor, further exhibiting the close relationship between strains in this cave and SARS-CoV. This work provides new insights into the origin and evolution of SARS-CoV and highlights the necessity of preparedness for future emergence of SARS-like diseases.

  8. Discovery of a rich gene pool of bat SARS-related coronaviruses provides new insights into the origin of SARS coronavirus

    PubMed Central

    Ge, Xing-Yi; Zhang, Wei; Li, Bei; Xie, Jia-Zheng; Shen, Xu-Rui; Zhang, Yun-Zhi; Wang, Ning; Luo, Dong-Sheng; Zheng, Xiao-Shuang; Wang, Mei-Niang; Wang, Lin-Fa

    2017-01-01

    A large number of SARS-related coronaviruses (SARSr-CoV) have been detected in horseshoe bats since 2005 in different areas of China. However, these bat SARSr-CoVs show sequence differences from SARS coronavirus (SARS-CoV) in different genes (S, ORF8, ORF3, etc) and are considered unlikely to represent the direct progenitor of SARS-CoV. Herein, we report the findings of our 5-year surveillance of SARSr-CoVs in a cave inhabited by multiple species of horseshoe bats in Yunnan Province, China. The full-length genomes of 11 newly discovered SARSr-CoV strains, together with our previous findings, reveals that the SARSr-CoVs circulating in this single location are highly diverse in the S gene, ORF3 and ORF8. Importantly, strains with high genetic similarity to SARS-CoV in the hypervariable N-terminal domain (NTD) and receptor-binding domain (RBD) of the S1 gene, the ORF3 and ORF8 region, respectively, were all discovered in this cave. In addition, we report the first discovery of bat SARSr-CoVs highly similar to human SARS-CoV in ORF3b and in the split ORF8a and 8b. Moreover, SARSr-CoV strains from this cave were more closely related to SARS-CoV in the non-structural protein genes ORF1a and 1b compared with those detected elsewhere. Recombination analysis shows evidence of frequent recombination events within the S gene and around the ORF8 between these SARSr-CoVs. We hypothesize that the direct progenitor of SARS-CoV may have originated after sequential recombination events between the precursors of these SARSr-CoVs. Cell entry studies demonstrated that three newly identified SARSr-CoVs with different S protein sequences are all able to use human ACE2 as the receptor, further exhibiting the close relationship between strains in this cave and SARS-CoV. This work provides new insights into the origin and evolution of SARS-CoV and highlights the necessity of preparedness for future emergence of SARS-like diseases. PMID:29190287

  9. NDM29, a RNA polymerase III-dependent non coding RNA, promotes amyloidogenic processing of APP and amyloid β secretion.

    PubMed

    Massone, Sara; Ciarlo, Eleonora; Vella, Serena; Nizzari, Mario; Florio, Tullio; Russo, Claudio; Cancedda, Ranieri; Pagano, Aldo

    2012-07-01

    Neuroblastoma Differentiation Marker 29 (NDM29) is a RNA polymerase (pol) III-transcribed non-coding (nc) RNA whose synthesis drives neuroblastoma (NB) cell differentiation to a nonmalignant neuron-like phenotype. Since in this process a complex pattern of molecular changes is associated to plasma membrane protein repertoire we hypothesized that the expression of NDM29 might influence also key players of neurodegenerative pathways. In this work we show that the NDM29-dependent cell maturation induces amyloid precursor protein (APP) synthesis, leading to the increase of amyloid β peptide (Aβ) secretion and the concomitant increment of Aβ x-42/Aβ x-40 ratio. We also demonstrate that the expression of NDM29 RNA, and the consequent increase of Aβ formation, can be promoted by inflammatory stimuli (and repressed by anti-inflammatory drugs). Moreover, NDM29 expression was detected in normal human brains although an abnormal increased synthesis of this ncRNA is induced in patients affected by neurodegenerative diseases. Therefore, the complex of events triggered by NDM29 expression induces a condition that favors the formation of Aβ peptides in the extracellular space, as it may occur in Alzheimer's Disease (AD). In addition, these data unexpectedly show that a pol III-dependent small RNA can act as key regulator of brain physiology and/or pathology suggesting that a better knowledge of this portion of the human transcriptome might provide hints for neurodegeneration studies. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Host Long Noncoding RNA lncRNA-PAAN Regulates the Replication of Influenza A Virus.

    PubMed

    Wang, Jing; Wang, Yujia; Zhou, Rui; Zhao, Jianyuan; Zhang, Yongxin; Yi, Dongrong; Li, Quanjie; Zhou, Jinming; Guo, Fei; Liang, Chen; Li, Xiaoyu; Cen, Shan

    2018-06-16

    The productive infection of influenza A virus (IAV) depends on host factors. However, the involvement of long non-coding RNAs (lncRNAs) in IAV infection remains largely uninvestigated. In this work, we have discovered a human lncRNA, named lncRNA-PAAN (PA-associated noncoding RNA) that enhances IAV replication. The level of lncRNA-PAAN increases upon infection of IAV, but not other viruses, nor interferon treatment, suggesting specific up-regulation of lncRNA-PAAN expression by IAV. Silencing lncRNA-PAAN significantly decreases IAV replication through impairing the activity of viral RNA-dependent RNA polymerase (RdRp). This function of lncRNA-PAAN is a result of its association with viral PA protein, a key component of IAV RNA polymerase complex. Consequently, depletion of lncRNA-PAAN prevents the formation of functional RdRp. Together, these results suggest that lncRNA-PAAN promotes the assembly of viral RNA polymerase, thus warranting efficient viral RNA synthesis. Elucidating the functions of lncRNAs in IAV infection is expected to advance our understanding of IAV pathogenesis and open new avenues to the development of novel anti-IAV therapeutics.

  11. Determining miRNA Expression Levels in Degraded RNA Samples Using Real-Time RT-qPCR and Microarray Technologies

    PubMed Central

    Tighe, S.; Holbrook, J.; Nadella, V.; Carmical, R.; Sol-Church, K.; Yueng, A.T.; Chittur, S.

    2011-01-01

    The Nucleic Acid Research Group (NARG) has previously conducted studies evaluating the impact of RNA integrity and priming strategies on cDNA synthesis and real-time RT-qPCR. The results of last year's field study as it relates to degraded RNA will be presented. In continuation of the RNA integrity theme, this year's study was designed to evaluate the impact of RNA integrity on the analysis of miRNA expression using real-time RT-qPCR. Target section was based on data obtained by the Microarray Research Group (MARG) and other published data from next gen sequencing. These 9 miRNAs represent three groups of miRNA that are expressed at low, medium or high levels in the First Choice human brain reference RNA sample. Two popular RT priming strategies tested in this study include the Megaplex miRNA TaqMan assay (ABI) and the RT2 miRNA qPCR assay (Qiagen/SA Biosciences). The basis for the ABI assay design is a target-specific stem-loop structure and reverse-transcription primer, while the Qiagen design combines poly(A) tailing and a universal reverse transcription in one cDNA synthesis reaction. For this study, the human brain reference RNA was subject to controlled degradation using RNase A to RIN (RNA Integrity Number) values of 7 (good), 4 (moderately degraded), and 2 (severely degraded).These templates were then used to assess both RT methods. In addition to this real-time RT-qPCR data, the same RNA templates were further analyzed using universal poly(A) tailing and hybridization to Affymetrix miRNA GeneChips. This talk will provide insights into RT priming strategies for miRNA and contrast the qPCR results obtained using different technologies.

  12. A study of the dimer formation of Rous sarcoma virus RNA and of its effect on viral protein synthesis in vitro.

    PubMed Central

    Bieth, E; Gabus, C; Darlix, J L

    1990-01-01

    The genetic material of all retroviruses examined so far is an RNA dimer where two identical RNA subunits are joined at their 5' ends by a structure named dimer linkage structure (DLS). Since the precise location and structure of the DLS as well as the mechanism and role(s) of RNA dimerization remain unclear, we analysed the dimerization process of Rous sarcoma virus (RSV) RNA. For this purpose we set up an in vitro model for RSV RNA dimerization. Using this model RSV RNA was shown to form dimeric molecules and this dimerization process was greatly activated by nucleocapsid protein (NCp12) of RSV. Furthermore, RSV RNA dimerization was performed in the presence of complementary 5'32P-DNA oligomers in order to probe the monomer and dimer forms of RSV RNA. Data indicated that the DLS of RSV RNA probably maps between positions 544-564 from the 5' end. In an attempt to define sequences needed for the dimerization of RSV RNA, deletion mutageneses were generated in the 5' 600 nt. The results showed that the dimer promoting sequences probably are located within positions 208-270 and 400-600 from the 5' end and hence possibly encompassing the cis-acting elements needed for the specific encapsidation of RSV genomic RNA. Also it is reported that synthesis of the polyprotein precursor Pr76gag is inhibited upon dimerization of RSV RNA. These results suggest that dimerization and encapsidation of genome length RSV RNA might be linked in the course of virion formation since they appear to be under the control of the same cis elements, E and DLS, and the trans-acting factor nucleocapsid protein NCp12. Images PMID:2155394

  13. The replisome uses mRNA as a primer after colliding with RNA polymerase.

    PubMed

    Pomerantz, Richard T; O'Donnell, Mike

    2008-12-11

    Replication forks are impeded by DNA damage and protein-nucleic acid complexes such as transcribing RNA polymerase. For example, head-on collision of the replisome with RNA polymerase results in replication fork arrest. However, co-directional collision of the replisome with RNA polymerase has little or no effect on fork progression. Here we examine co-directional collisions between a replisome and RNA polymerase in vitro. We show that the Escherichia coli replisome uses the RNA transcript as a primer to continue leading-strand synthesis after the collision with RNA polymerase that is displaced from the DNA. This action results in a discontinuity in the leading strand, yet the replisome remains intact and bound to DNA during the entire process. These findings underscore the notable plasticity by which the replisome operates to circumvent obstacles in its path and may explain why the leading strand is synthesized discontinuously in vivo.

  14. Ribozyme-mediated cleavage of c-fos mRNA reduces gene expression of DNA synthesis enzymes and metallothionein.

    PubMed Central

    Scanlon, K J; Jiao, L; Funato, T; Wang, W; Tone, T; Rossi, J J; Kashani-Sabet, M

    1991-01-01

    The c-fos gene product Fos has been implicated in many cellular processes, including signal transduction, DNA synthesis, and resistance to antineoplastic agents. A fos ribozyme (catalytic RNA) was designed to evaluate the effects of suppressing Fos protein synthesis on expression of enzymes involved in DNA synthesis, DNA repair, and drug resistance. DNA encoding the fos ribozyme (fosRb) was cloned into the pMAMneo expression plasmid, and the resultant vector was transfected into A2780DDP cells resistant to the chemotherapeutic agent cisplatin. The parental drug-sensitive A2780S cells were transfected with the pMMV vector containing the c-fos gene. Morphological alterations were accompanied by significant changes in pharmacological sensitivity in both c-fos- and fosRb-transfected cells. pMAMneo fosRb transfectants revealed decreased c-fos gene expression, concomitant with reduced thymidylate (dTMP) synthase, DNA polymerase beta, topoisomerase I, and metallothionein IIA mRNAs. In contrast, c-myc expression was elevated after fos ribozyme action. Insertion of a mutant ribozyme, mainly capable of antisense activity, into A2780DDP cells resulted in smaller reductions in c-fos gene expression and in cisplatin resistance than the active ribozyme. These studies establish a role for c-fos in drug resistance and in mediating DNA synthesis and repair processes by modulating expression of genes such as dTMP synthase, DNA polymerase beta, and topoisomerase I. These studies also suggest the utility of ribozymes in the analysis of cellular gene expression. Images PMID:1660142

  15. Thermostable group II intron reverse transcriptase fusion proteins and their use in cDNA synthesis and next-generation RNA sequencing.

    PubMed

    Mohr, Sabine; Ghanem, Eman; Smith, Whitney; Sheeter, Dennis; Qin, Yidan; King, Olga; Polioudakis, Damon; Iyer, Vishwanath R; Hunicke-Smith, Scott; Swamy, Sajani; Kuersten, Scott; Lambowitz, Alan M

    2013-07-01

    Mobile group II introns encode reverse transcriptases (RTs) that function in intron mobility ("retrohoming") by a process that requires reverse transcription of a highly structured, 2-2.5-kb intron RNA with high processivity and fidelity. Although the latter properties are potentially useful for applications in cDNA synthesis and next-generation RNA sequencing (RNA-seq), group II intron RTs have been difficult to purify free of the intron RNA, and their utility as research tools has not been investigated systematically. Here, we developed general methods for the high-level expression and purification of group II intron-encoded RTs as fusion proteins with a rigidly linked, noncleavable solubility tag, and we applied them to group II intron RTs from bacterial thermophiles. We thus obtained thermostable group II intron RT fusion proteins that have higher processivity, fidelity, and thermostability than retroviral RTs, synthesize cDNAs at temperatures up to 81°C, and have significant advantages for qRT-PCR, capillary electrophoresis for RNA-structure mapping, and next-generation RNA sequencing. Further, we find that group II intron RTs differ from the retroviral enzymes in template switching with minimal base-pairing to the 3' ends of new RNA templates, making it possible to efficiently and seamlessly link adaptors containing PCR-primer binding sites to cDNA ends without an RNA ligase step. This novel template-switching activity enables facile and less biased cloning of nonpolyadenylated RNAs, such as miRNAs or protein-bound RNA fragments. Our findings demonstrate novel biochemical activities and inherent advantages of group II intron RTs for research, biotechnological, and diagnostic methods, with potentially wide applications.

  16. Animal origins of SARS coronavirus: possible links with the international trade in small carnivores.

    PubMed Central

    Bell, Diana; Roberton, Scott; Hunter, Paul R

    2004-01-01

    The search for animal host origins of severe acute respiratory syndrome (SARS) coronavirus has so far remained focused on wildlife markets, restaurants and farms within China. A significant proportion of this wildlife enters China through an expanding regional network of illegal, international wildlife trade. We present the case for extending the search for ancestral coronaviruses and their hosts across international borders into countries such as Vietnam and Lao People's Democratic Republic, where the same guilds of species are found on sale in similar wildlife markets or food outlets. The three species that have so far been implicated, a viverrid, a mustelid and a canid, are part of a large suite of small carnivores distributed across this region currently overexploited by this international wildlife trade. A major lesson from SARS is that the underlying roots of newly emergent zoonotic diseases may lie in the parallel biodiversity crisis of massive species loss as a result of overexploitation of wild animal populations and the destruction of their natural habitats by increasing human populations. To address these dual threats to the long-term future of biodiversity, including man, requires a less anthropocentric and more interdisciplinary approach to problems that require the combined research expertise of ecologists, conservation biologists, veterinarians, epidemiologists, virologists, as well as human health professionals. PMID:15306396

  17. Animal origins of SARS coronavirus: possible links with the international trade in small carnivores.

    PubMed

    Bell, Diana; Roberton, Scott; Hunter, Paul R

    2004-07-29

    The search for animal host origins of severe acute respiratory syndrome (SARS) coronavirus has so far remained focused on wildlife markets, restaurants and farms within China. A significant proportion of this wildlife enters China through an expanding regional network of illegal, international wildlife trade. We present the case for extending the search for ancestral coronaviruses and their hosts across international borders into countries such as Vietnam and Lao People's Democratic Republic, where the same guilds of species are found on sale in similar wildlife markets or food outlets. The three species that have so far been implicated, a viverrid, a mustelid and a canid, are part of a large suite of small carnivores distributed across this region currently overexploited by this international wildlife trade. A major lesson from SARS is that the underlying roots of newly emergent zoonotic diseases may lie in the parallel biodiversity crisis of massive species loss as a result of overexploitation of wild animal populations and the destruction of their natural habitats by increasing human populations. To address these dual threats to the long-term future of biodiversity, including man, requires a less anthropocentric and more interdisciplinary approach to problems that require the combined research expertise of ecologists, conservation biologists, veterinarians, epidemiologists, virologists, as well as human health professionals.

  18. Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

    PubMed Central

    Rublack, Nico

    2014-01-01

    Summary Over the past 20 years, the generation of functional RNAs by in vitro selection has become a standard technique. Apart from aptamers for simple binding of defined ligands, also RNAs for catalysis of chemical reactions have been selected. In the latter case, a key step often is the conjugation of one of the two reactants to the library, requiring suitable strategies for terminal or internal RNA functionalization. With the aim of selecting a ribozyme for deamination of cytidine, we have set up a selection scheme involving the attachment of the cytidine acting as deamination substrate to the 3'-terminus of the RNAs in the library, and library immobilization. Here, we report the synthesis of a bifunctional cytidine derivative suitable for conjugation to RNA and linkage of the conjugated library to a streptavidine-coated surface. Successful conjugation of the cytidine derivative to the 3'-terminus of a model RNA is demonstrated. PMID:25246949

  19. Comparison of Polymerase Subunits from Double-Stranded RNA Bacteriophages

    PubMed Central

    Yang, Hongyan; Makeyev, Eugene V.; Bamford, Dennis H.

    2001-01-01

    The family Cystoviridae comprises several bacteriophages with double-stranded RNA (dsRNA) genomes. We have previously purified the catalytic polymerase subunit (Pol) of one of the Cystoviridae members, bacteriophage φ6, and shown that the protein can catalyze RNA synthesis in vitro. In this reaction, both bacteriophage-specific and heterologous RNAs can serve as templates, but those containing 3′ termini from the φ6 minus strands are favored. This provides a molecular basis for the observation that only plus strands, not minus strands, are transcribed from φ6 dsRNA segments in vivo. To test whether such a regulatory mechanism is also found in other dsRNA viruses, we purified recombinant Pol subunits from the φ6-related bacteriophages φ8 and φ13 and assayed their polymerase activities in vitro. The enzymes catalyze template-dependent RNA synthesis using both single-stranded-RNA (ssRNA) and dsRNA templates. However, they differ from each other as well as from φ6 Pol in certain biochemical properties. Notably, each polymerase demonstrates a distinct preference for ssRNAs bearing short 3′-terminal sequences from the virus-specific minus strands. This suggests that, in addition to other factors, RNA transcription in Cystoviridae is controlled by the template specificity of the polymerase subunit. PMID:11602748

  20. Analysis of the roles of cyclin B1 and cyclin B2 in porcine oocyte maturation by inhibiting synthesis with antisense RNA injection.

    PubMed

    Kuroda, Takao; Naito, Kunihiko; Sugiura, Koji; Yamashita, Masakane; Takakura, Ikuko; Tojo, Hideaki

    2004-01-01

    The function of cyclin B1 (CB1) and cyclin B2 (CB2) during porcine oocyte maturation was investigated by injecting oocytes with their antisense RNAs (asRNAs). At first, protein levels of both cyclin Bs were examined by immunoblotting, revealing that immature oocytes had only CB2, at a level comparable to 1/20 to 1/40 of that detected in first metaphase oocytes. Both cyclin B syntheses were started around germinal vesicle breakdown (GVBD); CB1 and CB2 peaked at the second metaphase and first metaphase, respectively. We obtained a porcine CB2 cDNA fragment, which was 88% homologous with human CB2, by reverse-transcriptase polymerase chain reaction (RT-PCR) using total RNAs of immature porcine oocytes and a primer set of human CB2. Specific asRNAs of CB1 and CB2 were prepared in vitro. Then one, the other, or both were injected into the cytoplasm of immature oocytes. CB1 asRNA inhibited CB1 synthesis specifically; the injected oocytes underwent first meiosis normally but could not arrest at the second meiotic metaphase. CB2 asRNA inhibited CB2 synthesis specifically, but had almost no effect on the maturation of injected oocytes. When both CB1 and CB2 asRNAs were injected, synthesis of both cyclin Bs was inhibited, and GVBD was significantly suppressed but occurred slowly. These results suggest that CB1 is the principal molecule for regulation in mammalian oocyte maturation, whereas CB2 has only an accessory role. They also show that in porcine oocytes, cyclin B synthesis is not necessary for GVBD induction itself, but synthesis of at least one cyclin B, CB1 or CB2, is necessary for GVBD induction in a normal time course.

  1. Interactome of two diverse RNA granules links mRNA localization to translational repression in neurons.

    PubMed

    Fritzsche, Renate; Karra, Daniela; Bennett, Keiryn L; Ang, Foong Yee; Heraud-Farlow, Jacki E; Tolino, Marco; Doyle, Michael; Bauer, Karl E; Thomas, Sabine; Planyavsky, Melanie; Arn, Eric; Bakosova, Anetta; Jungwirth, Kerstin; Hörmann, Alexandra; Palfi, Zsofia; Sandholzer, Julia; Schwarz, Martina; Macchi, Paolo; Colinge, Jacques; Superti-Furga, Giulio; Kiebler, Michael A

    2013-12-26

    Transport of RNAs to dendrites occurs in neuronal RNA granules, which allows local synthesis of specific proteins at active synapses on demand, thereby contributing to learning and memory. To gain insight into the machinery controlling dendritic mRNA localization and translation, we established a stringent protocol to biochemically purify RNA granules from rat brain. Here, we identified a specific set of interactors for two RNA-binding proteins that are known components of neuronal RNA granules, Barentsz and Staufen2. First, neuronal RNA granules are much more heterogeneous than previously anticipated, sharing only a third of the identified proteins. Second, dendritically localized mRNAs, e.g., Arc and CaMKIIα, associate selectively with distinct RNA granules. Third, our work identifies a series of factors with known roles in RNA localization, translational control, and RNA quality control that are likely to keep localized transcripts in a translationally repressed state, often in distinct types of RNPs. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  2. High Prevalence of Middle East Respiratory Coronavirus in Young Dromedary Camels in Jordan.

    PubMed

    van Doremalen, Neeltje; Hijazeen, Zaidoun S K; Holloway, Peter; Al Omari, Bilal; McDowell, Chester; Adney, Danielle; Talafha, Hani A; Guitian, Javier; Steel, John; Amarin, Nadim; Tibbo, Markos; Abu-Basha, Ehab; Al-Majali, Ahmad M; Munster, Vincent J; Richt, Juergen A

    2017-02-01

    Prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) was determined in 45 dromedary camels from two geographically separated herds in Jordan. Virus shedding was only detected in swabs obtained from the respiratory tract and primarily observed in camels younger than 3 years. MERS-CoV seroprevalence increased with age of camels. Bovine and sheep sera were seronegative. Phylogenetic analysis of partial S2 clustered the Jordanian MERS-CoV strains with contemporary MERS-CoV strains associated with nosocomial outbreaks.

  3. Evaluation of bovine coronavirus antibody levels, virus shedding, and respiratory disease incidence throughout the beef cattle production cycle

    USDA-ARS?s Scientific Manuscript database

    Objective- Determine how levels of serum antibody to bovine coronavirus (BCV) are related to virus shedding patterns and respiratory disease incidence in beef calves at various production stages. Animals- 890 crossbred beef calves from four separately managed herds at the U.S. Meat Animal Research C...

  4. Investigation of RNA Synthesis Using 5-Bromouridine Labelling and Immunoprecipitation.

    PubMed

    Kofoed, Rikke H; Betzer, Cristine; Lykke-Andersen, Søren; Molska, Ewa; Jensen, Poul H

    2018-05-03

    When steady state RNA levels are compared between two conditions, it is not possible to distinguish whether changes are caused by alterations in production or degradation of RNA. This protocol describes a method for measurement of RNA production, using 5-Bromouridine labelling of RNA followed by immunoprecipitation, which enables investigation of RNA synthesized within a short timeframe (e.g., 1 h). The advantage of 5-Bromouridine-labelling and immunoprecipitation over the use of toxic transcriptional inhibitors, such as α-amanitin and actinomycin D, is that there are no or very low effects on cell viability during short-term use. However, because 5-Bromouridine-immunoprecipitation only captures RNA produced within the short labelling time, slowly produced as well as rapidly degraded RNA can be difficult to measure by this method. The 5-Bromouridine-labelled RNA captured by 5-Bromouridine-immunoprecipitation can be analyzed by reverse transcription, quantitative polymerase chain reaction, and next generation sequencing. All types of RNA can be investigated, and the method is not limited to measuring mRNA as is presented in this example.

  5. Circular RNA: New Regulatory Molecules.

    PubMed

    Belousova, E A; Filipenko, M L; Kushlinskii, N E

    2018-04-01

    Circular RNA are a family of covalently closed circular RNA molecules, formed from pre-mRNA of coding genes by means of splicing (canonical and alternative noncanonical splicing). Maturation of circular RNA is regulated by cis- and trans-elements. Complete list of biological functions of these RNA is not yet compiled; however, their capacity to interact with specific microRNA and play a role of a depot attracts the greatest interest. This property makes circular RNA active regulatory transcription factors. Circular RNA have many advantages over their linear analogs: synthesis of these molecules is conservative, they are universal, characterized by clearly determined specificity, and are resistant to exonucleases. In addition, the level of their expression is often higher than that of their linear forms. It should be noted that expression of circular RNA is tissue-specific. Moreover, some correlations between changes in the repertoire and intensity of expression of circular RNA and the development of some pathologies have been detected. Circular RNA have certain advantages and can serve as new biomarkers for the diagnosis, prognosis, and evaluation of response to therapy.

  6. A Working Model of Protein Synthesis Using Lego(TM) Building Blocks.

    ERIC Educational Resources Information Center

    Templin, Mark A.; Fetters, Marcia K.

    2002-01-01

    Uses Lego building blocks to improve the effectiveness of teaching about protein synthesis. Provides diagrams and pictures for a 2-3 day student activity. Discusses mRNA, transfer RNA, and a protein synthesis model. (MVL)

  7. Ribonucleic Acid Synthesis and Glutamate Excretion in Escherichia coli

    PubMed Central

    Broda, Paul

    1968-01-01

    Cultures of Escherichia coli excreted glutamate into the medium when protein synthesis was blocked in RCrel strains or when it was blocked with chloramphenicol in either RCstr or RCrel strains. Both of these conditions resulted in continued ribonucleic acid (RNA) synthesis in the absence of protein synthesis. Glutamate was also excreted by both RCstr and RCrel strains when RNA synthesis was inhibited by uracil starvation or by treatment with actinomycin D. It is proposed that, in each of these cases, glutamate excretion resulted from an increase in the permeability of the cell membrane. PMID:4973126

  8. microRNA as a Potential Vector for the Propagation of Robustness in Protein Expression and Oscillatory Dynamics within a ceRNA Network

    PubMed Central

    Gérard, Claude; Novák, Béla

    2013-01-01

    microRNAs (miRNAs) are small noncoding RNAs that are important post-transcriptional regulators of gene expression. miRNAs can induce thresholds in protein synthesis. Such thresholds in protein output can be also achieved by oligomerization of transcription factors (TF) for the control of gene expression. First, we propose a minimal model for protein expression regulated by miRNA and by oligomerization of TF. We show that miRNA and oligomerization of TF generate a buffer, which increases the robustness of protein output towards molecular noise as well as towards random variation of kinetics parameters. Next, we extend the model by considering that the same miRNA can bind to multiple messenger RNAs, which accounts for the dynamics of a minimal competing endogenous RNAs (ceRNAs) network. The model shows that, through common miRNA regulation, TF can control the expression of all proteins formed by the ceRNA network, even if it drives the expression of only one gene in the network. The model further suggests that the threshold in protein synthesis mediated by the oligomerization of TF can be propagated to the other genes, which can increase the robustness of the expression of all genes in such ceRNA network. Furthermore, we show that a miRNA could increase the time delay of a “Goodwin-like” oscillator model, which may favor the occurrence of oscillations of large amplitude. This result predicts important roles of miRNAs in the control of the molecular mechanisms leading to the emergence of biological rhythms. Moreover, a model for the latter oscillator embedded in a ceRNA network indicates that the oscillatory behavior can be propagated, via the shared miRNA, to all proteins formed by such ceRNA network. Thus, by means of computational models, we show that miRNAs could act as vectors allowing the propagation of robustness in protein synthesis as well as oscillatory behaviors within ceRNA networks. PMID:24376695

  9. TIF-IA, the factor mediating growth-dependent control of ribosomal RNA synthesis, is the mammalian homolog of yeast Rrn3p.

    PubMed

    Bodem, J; Dobreva, G; Hoffmann-Rohrer, U; Iben, S; Zentgraf, H; Delius, H; Vingron, M; Grummt, I

    2000-08-01

    Cells carefully modulate the rate of rRNA transcription in order to prevent an overinvestment in ribosome synthesis under less favorable nutritional conditions. In mammals, growth-dependent regulation of RNA polymerase I (Pol I) transcription is mediated by TIF-IA, an essential initiation factor that is active in extracts from growing but not starved or cycloheximide-treated mammalian cells. Here we report the molecular cloning and functional characterization of recombinant TIF-IA, which turns out to be the mammalian homolog of the yeast factor Rrn3p. We demonstrate that TIF-IA interacts with Pol I in the absence of template DNA, augments Pol I transcription in vivo and rescues transcription in extracts from growth-arrested cells in vitro.

  10. Infection of cats with atypical feline coronaviruses harbouring a truncated form of the canine type I non-structural ORF3 gene.

    PubMed

    Le Poder, Sophie; Pham-Hung d'Alexandry d'Orangiani, Anne-Laure; Duarte, Lidia; Fournier, Annie; Horhogea, Cristina; Pinhas, Carine; Vabret, Astrid; Eloit, Marc

    2013-12-01

    Feline and canine coronaviruses (FCoV and CCoV, respectively) are common pathogens of cats and dogs sometimes leading to lethal infections named feline infectious peritonitis (FIP) and canine pantropic coronavirus infection. FCoV and CCoV are each subdivided into two serotypes, FCoV-I/II and CCoV-I/II. A phylogenetic relationship is evident between, on one hand, CCoV-I/FCoV-I, and on the other hand, CCoV-II/FCoV-II, suggesting that interspecies transmission can occur. The aim of the present study was to evaluate the prevalence of coronavirus (CoV)-infected cats according to their contact with dogs and to genetically analyse the CoV strains infecting cats. From 2003 to 2009, we collected 88 faecal samples from healthy cats and 11 ascitic fluids from FIP cats. We investigated the possible contact with dog in the household and collected dogs samples if appropriate. Out of 99 cat samples, 26 were coronavirus positive, with six cats living with at least one dog, thus showing that contact with dogs does not appear as a predisposing factor for cats CoV infections. Molecular and phylogenetic analyses of FCoV strains were conducted using partial N and S sequences. Six divergent strains were identified with the N gene clustering with CCoV-I whereas the 3' end of S was related to FCoV-I. Further analysis on those six samples was attempted by researching the presence of the ORF3 gene, the latter being peculiar to CCoV-I to date. We succeeded to amplify the ORF3 gene in five samples out of six. Thus, our data strongly suggest the circulation of atypical FCoV strains harbouring the CCoV-I ORF3 gene among cats. Moreover, the ORF3 genes recovered from the feline strains exhibited shared deletions, never described before, suggesting that these deletions could be critical in the adaptation of these strains to the feline host. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  11. Mechanism for priming DNA synthesis by yeast DNA Polymerase α

    PubMed Central

    Perera, Rajika L; Torella, Rubben; Klinge, Sebastian; Kilkenny, Mairi L; Maman, Joseph D; Pellegrini, Luca

    2013-01-01

    The DNA Polymerase α (Pol α)/primase complex initiates DNA synthesis in eukaryotic replication. In the complex, Pol α and primase cooperate in the production of RNA-DNA oligonucleotides that prime synthesis of new DNA. Here we report crystal structures of the catalytic core of yeast Pol α in unliganded form, bound to an RNA primer/DNA template and extending an RNA primer with deoxynucleotides. We combine the structural analysis with biochemical and computational data to demonstrate that Pol α specifically recognizes the A-form RNA/DNA helix and that the ensuing synthesis of B-form DNA terminates primer synthesis. The spontaneous release of the completed RNA-DNA primer by the Pol α/primase complex simplifies current models of primer transfer to leading- and lagging strand polymerases. The proposed mechanism of nucleotide polymerization by Pol α might contribute to genomic stability by limiting the amount of inaccurate DNA to be corrected at the start of each Okazaki fragment. DOI: http://dx.doi.org/10.7554/eLife.00482.001 PMID:23599895

  12. MicroRNA29a regulates IL-33-mediated tissue remodelling in tendon disease

    PubMed Central

    Millar, Neal L.; Gilchrist, Derek S.; Akbar, Moeed; Reilly, James H.; Kerr, Shauna C.; Campbell, Abigail L.; Murrell, George A. C.; Liew, Foo Y.; Kurowska-Stolarska, Mariola; McInnes, Iain B.

    2015-01-01

    MicroRNA (miRNA) has the potential for cross-regulation and functional integration of discrete biological processes during complex physiological events. Utilizing the common human condition tendinopathy as a model system to explore the cross-regulation of immediate inflammation and matrix synthesis by miRNA we observed that elevated IL-33 expression is a characteristic of early tendinopathy. Using in vitro tenocyte cultures and in vivo models of tendon damage, we demonstrate that such IL-33 expression plays a pivotal role in the transition from type 1 to type 3 collagen (Col3) synthesis and thus early tendon remodelling. Both IL-33 effector function, via its decoy receptor sST2, and Col3 synthesis are regulated by miRNA29a. Downregulation of miRNA29a in human tenocytes is sufficient to induce an increase in Col3 expression. These data provide a molecular mechanism of miRNA-mediated integration of the early pathophysiologic events that facilitate tissue remodelling in human tendon after injury. PMID:25857925

  13. Molecular and epidemiological characterization of a respiratory disease outbreak in pre-weaned beef calves associated with bovine coronavirus

    USDA-ARS?s Scientific Manuscript database

    Bovine coronavirus (BCV) is associated with respiratory tract infections in cattle of all ages; however, a temporal study to evaluate the effect of BCV immunity on virus shedding and bovine respiratory disease (BRD) incidence in pre-weaned beef calves has not been reported. Thus, we report here a pr...

  14. Single-nucleotide polymorphisms and mRNA expression for melatonin synthesis rate-limiting enzyme in recurrent depressive disorder.

    PubMed

    Gałecki, Piotr; Szemraj, Janusz; Bartosz, Grzegorz; Bieńkiewicz, Małgorzata; Gałecka, Elzbieta; Florkowski, Antoni; Lewiński, Andrzej; Karbownik-Lewińska, Małgorzata

    2010-05-01

    Depressive disorder (DD) is characterised by disturbances in blood melatonin concentration. It is well known that melatonin is involved in the control of circadian rhythms, sleep included. The use of melatonin and its analogues has been found to be effective in depression therapy. Melatonin synthesis is a multistage process, where the last stage is catalysed by acetylserotonin methyltransferase (ASMT), the reported rate-limiting melatonin synthesis enzyme. Taking into account the significance of genetic factors in depression development, the gene for ASMT may become an interesting focus for studies in patients with recurrent DD. The goal of the study was to evaluate two single-nucleotide polymorphisms (SNPs) (rs4446909; rs5989681) of the ASMT gene, as well as mRNA expression for ASMT in recurrent DD-affected patients. We genotyped two polymorphisms in a group of 181 recurrent DD patients and in 149 control subjects. The study was performed using the polymerase chain reaction/restriction fragment length polymorphism method. The distribution of genotypes in both studied SNPs in the ASMT gene differed significantly between DD and healthy subjects. The presence of AA genotype of rs4446909 polymorphism and of GG genotype of rs5989681 polymorphism was associated with lower risk for having recurrent DD. In turn, patients with depression were characterised by reduced mRNA expression for ASMT. In addition, ASMT transcript level in both recurrent DD patients and in healthy subjects depended significantly on genotype distributions in both polymorphisms. In conclusion, our results suggest the ASMT gene as a susceptibility gene for recurrent DD.

  15. Serologic survey for canine coronavirus in wolves from Alaska

    USGS Publications Warehouse

    Zarnke, Randall L.; Evermann, Jim F.; Ver Hoef, Jay M.; McNay, Mark E.; Boertje, Rodney D.; Gardner, Craig L.; Adams, Layne G.; Dale, Bruce W.; Burch, John W.

    2001-01-01

    Wolves (Canis lupus) were captured in three areas of Interior Alaska (USA). Four hundred twenty-five sera were tested for evidence of exposure to canine coronavirus by means of an indirect fluorescent antibody procedure. Serum antibody prevalence averaged 70% (167/240) during the spring collection period and 25% (46/185) during the autumn collection period. Prevalence was 0% (0/42) in the autumn pup cohort (age 4-5 mo), and 60% (58/97) in the spring pup cohort (age 9-10 mo). Prevalence was lowest in the Eastern Interior study area. A statistical model indicates that prevalence increased slightly each year in all three study areas. These results indicate that transmission occurs primarily during the winter months, antibody decay is quite rapid, and reexposure during the summer is rare.

  16. A rare cause of acute flaccid paralysis: Human coronaviruses

    PubMed Central

    Turgay, Cokyaman; Emine, Tekin; Ozlem, Koken; Muhammet, S. Paksu; Haydar, A. Tasdemir

    2015-01-01

    Acute flaccid paralysis (AFP) is a life-threatening clinical entity characterized by weakness in the whole body muscles often accompanied by respiratory and bulbar paralysis. The most common cause is Gullian–Barre syndrome, but infections, spinal cord diseases, neuromuscular diseases such as myasthenia gravis, drugs and toxins, periodic hypokalemic paralysis, electrolyte disturbances, and botulism should be considered as in the differential diagnosis. Human coronaviruses (HCoVs) cause common cold, upper and lower respiratory tract disease, but in the literature presentation with the lower respiratory tract infection and AFP has not been reported previously. In this study, pediatric case admitted with lower respiratory tract infection and AFP, who detected for HCoV 229E and OC43 co-infection by the real-time polymerase chain reaction, has been reported for the first time. PMID:26557177

  17. A rare cause of acute flaccid paralysis: Human coronaviruses.

    PubMed

    Turgay, Cokyaman; Emine, Tekin; Ozlem, Koken; Muhammet, S Paksu; Haydar, A Tasdemir

    2015-01-01

    Acute flaccid paralysis (AFP) is a life-threatening clinical entity characterized by weakness in the whole body muscles often accompanied by respiratory and bulbar paralysis. The most common cause is Gullian-Barre syndrome, but infections, spinal cord diseases, neuromuscular diseases such as myasthenia gravis, drugs and toxins, periodic hypokalemic paralysis, electrolyte disturbances, and botulism should be considered as in the differential diagnosis. Human coronaviruses (HCoVs) cause common cold, upper and lower respiratory tract disease, but in the literature presentation with the lower respiratory tract infection and AFP has not been reported previously. In this study, pediatric case admitted with lower respiratory tract infection and AFP, who detected for HCoV 229E and OC43 co-infection by the real-time polymerase chain reaction, has been reported for the first time.

  18. Rapid PCR-mediated synthesis of competitor molecules for accurate quantification of beta(2) GABA(A) receptor subunit mRNA.

    PubMed

    Vela, J; Vitorica, J; Ruano, D

    2001-12-01

    We describe a fast and easy method for the synthesis of competitor molecules based on non-specific conditions of PCR. RT-competitive PCR is a sensitive technique that allows quantification of very low quantities of mRNA molecules in small tissue samples. This technique is based on the competition established between the native and standard templates for nucleotides, primers or other factors during PCR. Thus, the most critical parameter is the use of good internal standards to generate a standard curve from which the amount of native sequences can be properly estimated. At the present time different types of internal standards and methods for their synthesis have been described. Normally, most of these methods are time-consuming and require the use of different sets of primers, different rounds of PCR or specific modifications, such as site-directed mutagenesis, that need subsequent analysis of the PCR products. Using our method, we obtained in a single round of PCR and with the same primer pair, competitor molecules that were successfully used in RT-competitive PCR experiments. The principal advantage of this method is high versatility and economy. Theoretically it is possible to synthesize a specific competitor molecule for each primer pair used. Finally, using this method we have been able to quantify the increase in the expression of the beta(2) GABA(A) receptor subunit mRNA that occurs during rat hippocampus development.

  19. Proteolytic activation of the SARS-coronavirus spike protein: cutting enzymes at the cutting edge of antiviral research.

    PubMed

    Simmons, Graham; Zmora, Pawel; Gierer, Stefanie; Heurich, Adeline; Pöhlmann, Stefan

    2013-12-01

    The severe acute respiratory syndrome (SARS) pandemic revealed that zoonotic transmission of animal coronaviruses (CoV) to humans poses a significant threat to public health and warrants surveillance and the development of countermeasures. The activity of host cell proteases, which cleave and activate the SARS-CoV spike (S) protein, is essential for viral infectivity and constitutes a target for intervention. However, the identities of the proteases involved have been unclear. Pioneer studies identified cathepsins and type II transmembrane serine proteases as cellular activators of SARS-CoV and demonstrated that several emerging viruses might exploit these enzymes to promote their spread. Here, we will review the proteolytic systems hijacked by SARS-CoV for S protein activation, we will discuss their contribution to viral spread in the host and we will outline antiviral strategies targeting these enzymes. This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10years of research on highly pathogenic human coronaviruses.'' Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Human Cytomegalovirus Strategies to Maintain and Promote mRNA Translation

    PubMed Central

    Vincent, Heather A.; Ziehr, Benjamin; Moorman, Nathaniel J.

    2016-01-01

    mRNA translation requires the ordered assembly of translation initiation factors and ribosomal subunits on a transcript. Host signaling pathways regulate each step in this process to match levels of protein synthesis to environmental cues. In response to infection, cells activate multiple defenses that limit viral protein synthesis, which viruses must counteract to successfully replicate. Human cytomegalovirus (HCMV) inhibits host defenses that limit viral protein expression and manipulates host signaling pathways to promote the expression of both host and viral proteins necessary for virus replication. Here we review key regulatory steps in mRNA translation, and the strategies used by HCMV to maintain protein synthesis in infected cells. PMID:27089357

  1. High Prevalence of Middle East Respiratory Coronavirus in Young Dromedary Camels in Jordan

    PubMed Central

    van Doremalen, Neeltje; Hijazeen, Zaidoun S.K.; Holloway, Peter; Al Omari, Bilal; McDowell, Chester; Adney, Danielle; Talafha, Hani A.; Guitian, Javier; Steel, John; Amarin, Nadim; Tibbo, Markos; Abu-Basha, Ehab; Al-Majali, Ahmad M.

    2017-01-01

    Abstract Prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) was determined in 45 dromedary camels from two geographically separated herds in Jordan. Virus shedding was only detected in swabs obtained from the respiratory tract and primarily observed in camels younger than 3 years. MERS-CoV seroprevalence increased with age of camels. Bovine and sheep sera were seronegative. Phylogenetic analysis of partial S2 clustered the Jordanian MERS-CoV strains with contemporary MERS-CoV strains associated with nosocomial outbreaks. PMID:28009529

  2. The SARS Coronavirus 3a protein binds calcium in its cytoplasmic domain.

    PubMed

    Minakshi, Rinki; Padhan, Kartika; Rehman, Safikur; Hassan, Md Imtaiyaz; Ahmad, Faizan

    2014-10-13

    The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) is a positive stranded RNA virus with ∼30kb genome. Among all open reading frames (orfs) of this virus, the orf3a is the largest, and encodes a protein of 274 amino acids, named as 3a protein. Sequence analysis suggests that the orf3a aligned to one calcium pump present in Plasmodium falciparum and the enzyme glutamine synthetase found in Leptospira interrogans. This sequence similarity was found to be limited only to amino acid residues 209-264 which form the cytoplasmic domain of the orf3a. Furthermore, this region was predicted to be involved in the calcium binding. Owing to this hypothesis, we were driven to establish its calcium binding property in vitro. Here, we expressed and purified the cytoplasmic domain of the 3a protein, called Cyto3a, as a recombinant His-tagged protein in the E. coli. The calcium binding nature was established by performing various staining methods such as ruthenium red and stains-all. (45)Ca overlay method was also done to further support the data. Since the 3a protein forms ion channels, we were interested to see any conformational changes occurring in the Cyot3a upon calcium binding, using fluorescence spectroscopy and circular dichroism. These studies clearly indicate a significant change in the conformation of the Cyto3a protein after binding with calcium. Our results strongly suggest that the cytoplasmic domain of the 3a protein of SARS-CoV binds calcium in vitro, causing a change in protein conformation. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Rift valley fever virus nonstructural protein NSs promotes viral RNA replication and transcription in a minigenome system.

    PubMed

    Ikegami, Tetsuro; Peters, C J; Makino, Shinji

    2005-05-01

    Rift Valley fever virus (RVFV), which belongs to the genus Phlebovirus, family Bunyaviridae, has a tripartite negative-strand genome (S, M, and L segments) and is an important mosquito-borne pathogen for domestic animals and humans. We established an RVFV T7 RNA polymerase-driven minigenome system in which T7 RNA polymerase from an expression plasmid drove expression of RNA transcripts for viral proteins and minigenome RNA transcripts carrying a reporter gene between both termini of the M RNA segment in 293T cells. Like other viruses of the Bunyaviridae family, replication and transcription of the RVFV minigenome required expression of viral N and L proteins. Unexpectedly, the coexpression of an RVFV nonstructural protein, NSs, with N and L proteins resulted in a significant enhancement of minigenome RNA replication. Coexpression of NSs protein with N and L proteins also enhanced minigenome mRNA transcription in the cells expressing viral-sense minigenome RNA transcripts. NSs protein expression increased the RNA replication of minigenomes that originated from S and L RNA segments. Enhancement of minigenome RNA synthesis by NSs protein occurred in cells lacking alpha/beta interferon (IFN-alpha/beta) genes, indicating that the effect of NSs protein on minigenome RNA replication was unrelated to a putative NSs protein-induced inhibition of IFN-alpha/beta production. Our finding that RVFV NSs protein augmented minigenome RNA synthesis was in sharp contrast to reports that Bunyamwera virus (genus Bunyavirus) NSs protein inhibits viral minigenome RNA synthesis, suggesting that RVFV NSs protein and Bunyamwera virus NSs protein have distinctly different biological roles in viral RNA synthesis.

  4. MicroRNA-133 inhibits behavioral aggregation by controlling dopamine synthesis in locusts.

    PubMed

    Yang, Meiling; Wei, Yuanyuan; Jiang, Feng; Wang, Yanli; Guo, Xiaojiao; He, Jing; Kang, Le

    2014-02-01

    Phenotypic plasticity is ubiquitous and primarily controlled by interactions between environmental and genetic factors. The migratory locust, a worldwide pest, exhibits pronounced phenotypic plasticity, which is a population density-dependent transition that occurs between the gregarious and solitary phases. Genes involved in dopamine synthesis have been shown to regulate the phase transition of locusts. However, the function of microRNAs in this process remains unknown. In this study, we report the participation of miR-133 in dopamine production and the behavioral transition by negatively regulating two critical genes, henna and pale, in the dopamine pathway. miR-133 participated in the post-transcriptional regulation of henna and pale by binding to their coding region and 3' untranslated region, respectively. miR-133 displayed cellular co-localization with henna/pale in the protocerebrum, and its expression in the protocerebrum was negatively correlated with henna and pale expression. Moreover, miR-133 agomir delivery suppressed henna and pale expression, which consequently decreased dopamine production, thus resulting in the behavioral shift of the locusts from the gregarious phase to the solitary phase. Increasing the dopamine content could rescue the solitary phenotype, which was induced by miR-133 agomir delivery. Conversely, miR-133 inhibition increased the expression of henna and pale, resulting in the gregarious-like behavior of solitary locusts; this gregarious phenotype could be rescued by RNA interference of henna and pale. This study shows the novel function and modulation pattern of a miRNA in phenotypic plasticity and provides insight into the underlying molecular mechanisms of the phase transition of locusts.

  5. Decreased ATP synthesis is phenotypically expressed during increased energy demand in fibroblasts containing mitochondrial tRNA mutations.

    PubMed

    James, A M; Sheard, P W; Wei, Y H; Murphy, M P

    1999-01-01

    Mutations in the tRNA genes of mitochondrial DNA (mtDNA) cause the debilitating MELAS (mitochondrial, myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and MERRF (myoclonic epilepsy and ragged-red fibres) syndromes. These mtDNA mutations affect respiratory chain function, apparently without decreasing cellular ATP concentration [Moudy et al. (1995) PNAS, 92, 729-733]. To address this issue, we investigated the role of mitochondrial ATP synthesis in fibroblasts from MELAS and MERRF patients. The maximum rate of mitochondrial ATP synthesis was decreased by 60-88%, as a consequence of the decrease in the proton electrochemical potential gradient of MELAS and MERRF mitochondria. However, in quiescent fibroblasts neither ATP concentration or the ATP/ADP ratio was affected by the lowered rate of ATP synthesis. We hypothesized that the low ATP demand of quiescent fibroblasts masked the mitochondrial ATP synthesis defect and that this defect might become apparent during higher ATP use. To test this we simulated high energy demand by titrating cells with gramicidin, an ionophore that stimulates ATP hydrolysis by the plasma membrane Na+/K+-ATPase. We found a threshold gramicidin concentration in control cells at which both the ATP/ADP ratio and the plasma membrane potential decreased dramatically, due to ATP demand by the Na+/K+-ATPase outstripping mitochondrial ATP synthesis. In MELAS and MERRF fibroblasts the corresponding threshold concentrations of gramicidin were 2-20-fold lower than those for control cells. This is the first demonstration that cells containing mtDNA mutations are particularly sensitive to increased ATP demand and this has several implications for how mitochondrial dysfunction contributes to disease pathophysiology. In particular, the increased susceptibility to plasma membrane depolarization will render neurons with dysfunctional mitochondria susceptible to excitotoxic cell death.

  6. RNA Polymerase II cluster dynamics predict mRNA output in living cells

    PubMed Central

    Cho, Won-Ki; Jayanth, Namrata; English, Brian P; Inoue, Takuma; Andrews, J Owen; Conway, William; Grimm, Jonathan B; Spille, Jan-Hendrik; Lavis, Luke D; Lionnet, Timothée; Cisse, Ibrahim I

    2016-01-01

    Protein clustering is a hallmark of genome regulation in mammalian cells. However, the dynamic molecular processes involved make it difficult to correlate clustering with functional consequences in vivo. We developed a live-cell super-resolution approach to uncover the correlation between mRNA synthesis and the dynamics of RNA Polymerase II (Pol II) clusters at a gene locus. For endogenous β-actin genes in mouse embryonic fibroblasts, we observe that short-lived (~8 s) Pol II clusters correlate with basal mRNA output. During serum stimulation, a stereotyped increase in Pol II cluster lifetime correlates with a proportionate increase in the number of mRNAs synthesized. Our findings suggest that transient clustering of Pol II may constitute a pre-transcriptional regulatory event that predictably modulates nascent mRNA output. DOI: http://dx.doi.org/10.7554/eLife.13617.001 PMID:27138339

  7. tRNA travels from the cytoplasm to organelles

    PubMed Central

    Rubio, Mary Anne T.; Hopper, Anita K.

    2011-01-01

    Transfer RNAs (tRNAs) encoded by the nuclear genome are surprisingly dynamic. Although tRNAs function in protein synthesis occurring on cytoplasmic ribosomes, tRNAs can transit from the cytoplasm to the nucleus and then again return to the cytoplasm by a process known as the tRNA retrograde process. Subsets of the cytoplasmic tRNAs are also imported into mitochondria and function in mitochondrial protein synthesis. The numbers of tRNA species that are imported into mitchondria differ among organisms, ranging from just a few to the entire set needed to decode mitochondrially encoded mRNAs. For some tRNAs, import is dependent on the mitochondrial protein import machinery, whereas the majority of tRNA mitochondrial import is independent of this machinery. Although cytoplasmic proteins and proteins located on the mitochondrial surface participating in the tRNA import process have been described for several organisms, the identity of these proteins differ among organisms. Likewise, the tRNA determinants required for mitochondrial import differ among tRNA species and organisms. Here, we present an overview and discuss the current state of knowledge regarding the mechanisms involved in the tRNA retrograde process and continue with an overview of tRNA import into mitochondria. Finally, we highlight areas of future research to understand the function and regulation of movement of tRNAs between the cytoplasm and organelles. PMID:21976284

  8. The Middle East Respiratory Syndrome Coronavirus - A Continuing Risk to Global Health Security.

    PubMed

    Azhar, Esam I; Lanini, Simone; Ippolito, Giuseppe; Zumla, Alimuddin

    2017-01-01

    Two new zoonotic coronaviruses causing disease in humans (Zumla et al. 2015a; Hui and Zumla 2015; Peiris et al. 2003; Yu et al. 2014) have been the focus of international attention for the past 14 years due to their epidemic potential; (1) The Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) (Peiris et al. 2003) first discovered in China in 2001 caused a major global epidemic of the Severe Acute Respiratory Syndrome (SARS). (2) The Middle East respiratory syndrome coronavirus (MERS-CoV) is a new corona virus isolated for the first time in a patients who died of severe lower respiratory tract infection in Jeddah (Saudi Arabia) in June 2012 (Zaki et al. 2012). The disease has been named Middle East Respiratory Syndrome (MERS) and it has remained on the radar of global public health authorities because of recurrent nosocomial and community outbreaks, and its association with severe disease and high mortality rates (Assiri et al. 2013a; Al-Abdallat et al. 2014; Memish et al. 2013a; Oboho et al. 2015; The WHO MERS-CoV Research Group 2013; Cotten et al. 2013a; Assiri et al. 2013b; Memish et al. 2013b; Azhar et al. 2014; Kim et al. 2015; Wang et al. 2015; Hui et al. 2015a). Cases of MERS have been reported from all continents and have been linked with travel to the Middle East (Hui et al. 2015a; WHO 2015c). The World Health Organization (WHO) have held nine meetings of the Emergency Committee (EC) convened by the Director-General under the International Health Regulations (IHR 2005) regarding MERS-CoV (WHO 2015c). There is wishful anticipation in the political and scientific communities that MERS-CoV like SARS-CoV will disappear with time. However it's been nearly 4 years since the first discovery of MERS-CoV, and MERS cases continue to be reported throughout the year from the Middle East (WHO 2015c). There is a large MERS-CoV camel reservoir, and there is no specific treatment or vaccine (Zumla et al. 2015a). With 10 million people visiting Saudi Arabia every

  9. Human Coronavirus NL63 Molecular Epidemiology and Evolutionary Patterns in Rural Coastal Kenya.

    PubMed

    Kiyuka, Patience K; Agoti, Charles N; Munywoki, Patrick K; Njeru, Regina; Bett, Anne; Otieno, James R; Otieno, Grieven P; Kamau, Everlyn; Clark, Taane G; van der Hoek, Lia; Kellam, Paul; Nokes, D James; Cotten, Matthew

    2018-05-05

    Human coronavirus NL63 (HCoV-NL63) is a globally endemic pathogen causing mild and severe respiratory tract infections with reinfections occurring repeatedly throughout a lifetime. Nasal samples were collected in coastal Kenya through community-based and hospital-based surveillance. HCoV-NL63 was detected with multiplex real-time reverse transcription PCR, and positive samples were targeted for nucleotide sequencing of the spike (S) protein. Additionally, paired samples from 25 individuals with evidence of repeat HCoV-NL63 infection were selected for whole-genome virus sequencing. HCoV-NL63 was detected in 1.3% (75/5573) of child pneumonia admissions. Two HCoV-NL63 genotypes circulated in Kilifi between 2008 and 2014. Full genome sequences formed a monophyletic clade closely related to contemporary HCoV-NL63 from other global locations. An unexpected pattern of repeat infections was observed with some individuals showing higher viral titers during their second infection. Similar patterns for 2 other endemic coronaviruses, HCoV-229E and HCoV-OC43, were observed. Repeat infections by HCoV-NL63 were not accompanied by detectable genotype switching. In this coastal Kenya setting, HCoV-NL63 exhibited low prevalence in hospital pediatric pneumonia admissions. Clade persistence with low genetic diversity suggest limited immune selection, and absence of detectable clade switching in reinfections indicates initial exposure was insufficient to elicit a protective immune response.

  10. A SARS-like cluster of circulating bat coronaviruses shows potential for human emergence.

    PubMed

    Menachery, Vineet D; Yount, Boyd L; Debbink, Kari; Agnihothram, Sudhakar; Gralinski, Lisa E; Plante, Jessica A; Graham, Rachel L; Scobey, Trevor; Ge, Xing-Yi; Donaldson, Eric F; Randell, Scott H; Lanzavecchia, Antonio; Marasco, Wayne A; Shi, Zhengli-Li; Baric, Ralph S

    2015-12-01

    The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome (MERS)-CoV underscores the threat of cross-species transmission events leading to outbreaks in humans. Here we examine the disease potential of a SARS-like virus, SHC014-CoV, which is currently circulating in Chinese horseshoe bat populations. Using the SARS-CoV reverse genetics system, we generated and characterized a chimeric virus expressing the spike of bat coronavirus SHC014 in a mouse-adapted SARS-CoV backbone. The results indicate that group 2b viruses encoding the SHC014 spike in a wild-type backbone can efficiently use multiple orthologs of the SARS receptor human angiotensin converting enzyme II (ACE2), replicate efficiently in primary human airway cells and achieve in vitro titers equivalent to epidemic strains of SARS-CoV. Additionally, in vivo experiments demonstrate replication of the chimeric virus in mouse lung with notable pathogenesis. Evaluation of available SARS-based immune-therapeutic and prophylactic modalities revealed poor efficacy; both monoclonal antibody and vaccine approaches failed to neutralize and protect from infection with CoVs using the novel spike protein. On the basis of these findings, we synthetically re-derived an infectious full-length SHC014 recombinant virus and demonstrate robust viral replication both in vitro and in vivo. Our work suggests a potential risk of SARS-CoV re-emergence from viruses currently circulating in bat populations.

  11. Broadly targeted multiprobe QPCR for detection of coronaviruses: Coronavirus is common among mallard ducks (Anas platyrhynchos).

    PubMed

    Muradrasoli, Shaman; Mohamed, Nahla; Hornyák, Akos; Fohlman, Jan; Olsen, Björn; Belák, Sándor; Blomberg, Jonas

    2009-08-01

    Coronaviruses (CoVs) can cause trivial or fatal disease in humans and in animals. Detection methods for a wide range of CoVs are needed, to understand viral evolution, host range, transmission and maintenance in reservoirs. A new concept, "Multiprobe QPCR", which uses a balanced mixture of competing discrete non- or moderately degenerated nuclease degradable (TaqMan) probes was employed. It provides a broadly targeted and rational single tube real-time reverse transcription PCR ("NQPCR") for the generic detection and discovery of CoV. Degenerate primers, previously published, and the new probes, were from a conserved stretch of open reading frame 1b, encoding the replicase. This multiprobe design reduced the degree of probe degeneration, which otherwise decreases the sensitivity, and allowed a preliminary classification of the amplified sequence directly from the QPCR trace. The split probe strategy allowed detection of down to 10 viral nucleic acid equivalents of CoV from all known CoV groups. Evaluation was with reference CoV strains, synthetic targets, human respiratory samples and avian fecal samples. Infectious-Bronchitis-Virus (IBV)-related variants were found in 7 of 35 sample pools, from 100 wild mallards (Anas platyrhynchos). Ducks may spread and harbour CoVs. NQPCR can detect a wide range of CoVs, as illustrated for humans and ducks.

  12. [RNA-synthesizing activity in the liver of rats after a flight on the Kosmos 1667 biosatellite].

    PubMed

    Makeeva, V F; Komolova, G S

    1987-01-01

    The effect of a short-term flight (7 days) on the RNA synthetic activity in isolated nuclei of the rat liver and its content of nucleic acids was investigated. Postflight the activity of RNA-polymerase, the key enzyme of RNA synthesis, increased. The endogenous synthesis of RNA in nuclei grew, probably, due to the change in the activity of RNA-polymerase. Conversely, the concentration of nucleic acids in the liver tended to decrease. The results obtained give evidence that the changes in the RNA synthetic apparatus of hepatocytes in short-term flights are similar in sign to those seen in long-term flights.

  13. Iron Induction of Ferritin Synthesis in Soybean Cell Suspensions

    PubMed Central

    Proudhon, Dominique; Briat, Jean-François; Lescure, Anne-Marie

    1989-01-01

    In animal cells specialized for iron storage, iron-induced accumulation of ferritin is known to result from a shift of stored mRNA from the ribonucleoprotein fraction to polysomes. Previous reports with bean leaves suggested that in plants iron induction of ferritin synthesis would result from a regulation at the transcriptional level (F van der Mark, F Bienfait, H van der Ende [1983] Biochem Biophys Res Commun 115:463-469). Soybean (Glycine max, cv Mandarin) cell suspension cultures have been used here to support these findings. Ferritin induction is obtained by addition of Fe-citrate to the culture medium. A good correlation is found between cellular iron content and the amount of ferritin accumulation. This protein accumulation corresponds to an increase of in vitro translatable ferritin mRNA. Addition of 4 micrograms actinomycin D per milliliter to the cultures inhibits completely in vivo RNA synthesis, whereas protein synthesis was poorly affected, at least for 24 hours. During the same time, this concentration of actinomycin D strongly inhibits the iron-induced synthesis of ferritin. These results show that in soybean cell cultures, the mechanism of regulation of ferritin synthesis in response to iron does not result from recruitment of preexisting mRNA. They confirm that in plant systems, ferritin synthesis results from increased transcription of the corresponding genes. Images Figure 2 Figure 3 Figure 5 PMID:16666812

  14. Iron induction of ferritin synthesis in soybean cell suspensions.

    PubMed

    Proudhon, D; Briat, J F; Lescure, A M

    1989-06-01

    In animal cells specialized for iron storage, iron-induced accumulation of ferritin is known to result from a shift of stored mRNA from the ribonucleoprotein fraction to polysomes. Previous reports with bean leaves suggested that in plants iron induction of ferritin synthesis would result from a regulation at the transcriptional level (F van der Mark, F Bienfait, H van der Ende [1983] Biochem Biophys Res Commun 115:463-469). Soybean (Glycine max, cv Mandarin) cell suspension cultures have been used here to support these findings. Ferritin induction is obtained by addition of Fe-citrate to the culture medium. A good correlation is found between cellular iron content and the amount of ferritin accumulation. This protein accumulation corresponds to an increase of in vitro translatable ferritin mRNA. Addition of 4 micrograms actinomycin D per milliliter to the cultures inhibits completely in vivo RNA synthesis, whereas protein synthesis was poorly affected, at least for 24 hours. During the same time, this concentration of actinomycin D strongly inhibits the iron-induced synthesis of ferritin. These results show that in soybean cell cultures, the mechanism of regulation of ferritin synthesis in response to iron does not result from recruitment of preexisting mRNA. They confirm that in plant systems, ferritin synthesis results from increased transcription of the corresponding genes.

  15. The role of epidermal growth factor receptor (EGFR) signaling in SARS coronavirus-induced pulmonary fibrosis.

    PubMed

    Venkataraman, Thiagarajan; Frieman, Matthew B

    2017-07-01

    Many survivors of the 2003 outbreak of severe acute respiratory syndrome (SARS) developed residual pulmonary fibrosis with increased severity seen in older patients. Autopsies of patients that died from SARS also showed fibrosis to varying extents. Pulmonary fibrosis can be occasionally seen as a consequence to several respiratory viral infections but is much more common after a SARS coronavirus (SARS-CoV) infection. Given the threat of future outbreaks of severe coronavirus disease, including Middle East respiratory syndrome (MERS), it is important to understand the mechanisms responsible for pulmonary fibrosis, so as to support the development of therapeutic countermeasures and mitigate sequelae of infection. In this article, we summarize pulmonary fibrotic changes observed after a SARS-CoV infection, discuss the extent to which other respiratory viruses induce fibrosis, describe available animal models to study the development of SARS-CoV induced fibrosis and review evidence that pulmonary fibrosis is caused by a hyperactive host response to lung injury mediated by epidermal growth factor receptor (EGFR) signaling. We summarize work from our group and others indicating that inhibiting EGFR signaling may prevent an excessive fibrotic response to SARS-CoV and other respiratory viral infections and propose directions for future research. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Effects of branched-chain volatile fatty acids on lactation performance and mRNA expression of genes related to fatty acid synthesis in mammary gland of dairy cows.

    PubMed

    Liu, Q; Wang, C; Guo, G; Huo, W J; Zhang, S L; Pei, C X; Zhang, Y L; Wang, H

    2018-02-12

    Branched-chain volatile fatty acids (BCVFA) supplements could promote lactation performance and milk quality by improving ruminal fermentation and milk fatty acid synthesis. This study was conducted to evaluate the effects of BCVFA supplementation on milk performance, ruminal fermentation, nutrient digestibility and mRNA expression of genes related to fatty acid synthesis in mammary gland of dairy cows. A total of 36 multiparous Chinese Holstein cows averaging 606±4.7 kg of BW, 65±5.2 day in milk (DIM) with daily milk production of 30.6±0.72 kg were assigned to one of four groups blocked by lactation number, milk yield and DIM. The treatments were control, low-BCVFA (LBCVFA), medium-BCVFA (MBCVFA) and high-BCVFA (HBCVFA) with 0, 30, 60 and 90 g BCVFA per cow per day, respectively. Experimental periods were 105 days with 15 days of adaptation and 90 days of data collection. Dry matter (DM) intake tended to increase, but BW changes were similar among treatments. Yields of actual milk, 4% fat corrected milk, milk fat and true protein linearly increased, but feed conversion ratio (FCR) linearly decreased with increasing BCVFA supplementation. Milk fat content linearly increased, but true protein content tended to increase. Contents of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0 and C15:0 fatty acids in milk fat linearly increased, whereas other fatty acids were not affected with increasing BCVFA supplementation. Ruminal pH, ammonia N concentration and propionate molar proportion linearly decreased, but total VFA production and molar proportions of acetate and butyrate linearly increased with increasing BCVFA supplementation. Consequently, acetate to propionate ratios linearly increased. Digestibilities of DM, organic matter, CP, NDF and ADF also linearly increased. In addition, mRNA expressions of peroxisome proliferator-activated receptor γ, sterol regulatory element-binding factor 1 and fatty acid-binding protein 3 linearly increased, mRNA expressions of acetyl

  17. Repurposing of Clinically Developed Drugs for Treatment of Middle East Respiratory Syndrome Coronavirus Infection

    PubMed Central

    Dyall, Julie; Coleman, Christopher M.; Hart, Brit J.; Venkataraman, Thiagarajan; Holbrook, Michael R.; Kindrachuk, Jason; Johnson, Reed F.; Olinger, Gene G.; Jahrling, Peter B.; Laidlaw, Monique; Johansen, Lisa M.; Lear-Rooney, Calli M.; Glass, Pamela J.; Hensley, Lisa E.

    2014-01-01

    Outbreaks of emerging infections present health professionals with the unique challenge of trying to select appropriate pharmacologic treatments in the clinic with little time available for drug testing and development. Typically, clinicians are left with general supportive care and often untested convalescent-phase plasma as available treatment options. Repurposing of approved pharmaceutical drugs for new indications presents an attractive alternative to clinicians, researchers, public health agencies, drug developers, and funding agencies. Given the development times and manufacturing requirements for new products, repurposing of existing drugs is likely the only solution for outbreaks due to emerging viruses. In the studies described here, a library of 290 compounds was screened for antiviral activity against Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV). Selection of compounds for inclusion in the library was dependent on current or previous FDA approval or advanced clinical development. Some drugs that had a well-defined cellular pathway as target were included. In total, 27 compounds with activity against both MERS-CoV and SARS-CoV were identified. The compounds belong to 13 different classes of pharmaceuticals, including inhibitors of estrogen receptors used for cancer treatment and inhibitors of dopamine receptor used as antipsychotics. The drugs identified in these screens provide new targets for in vivo studies as well as incorporation into ongoing clinical studies. PMID:24841273

  18. Multiply Intercalator-Substituted Cu(II) Cyclen Complexes as DNA Condensers and DNA/RNA Synthesis Inhibitors.

    PubMed

    Hormann, Jan; Malina, Jaroslav; Lemke, Oliver; Hülsey, Max J; Wedepohl, Stefanie; Potthoff, Jan; Schmidt, Claudia; Ott, Ingo; Keller, Bettina G; Brabec, Viktor; Kulak, Nora

    2018-05-07

    Many drugs that are applied in anticancer therapy such as the anthracycline doxorubicin contain DNA-intercalating 9,10-anthraquinone (AQ) moieties. When Cu(II) cyclen complexes were functionalized with up to three (2-anthraquinonyl)methyl substituents, they efficiently inhibited DNA and RNA synthesis resulting in high cytotoxicity (selective for cancer cells) accompanied by DNA condensation/aggregation phenomena. Molecular modeling suggests an unusual bisintercalation mode with only one base pair between the two AQ moieties and the metal complex as a linker. A regioisomer, in which the AQ moieties point in directions unfavorable for such an interaction, had a much weaker biological activity. The ligands alone and corresponding Zn(II) complexes (used as redox inert control compounds) also exhibited lower activity.

  19. Mechanism and Regulation of Protein Synthesis in Saccharomyces cerevisiae

    PubMed Central

    Dever, Thomas E.; Kinzy, Terri Goss; Pavitt, Graham D.

    2016-01-01

    In this review, we provide an overview of protein synthesis in the yeast Saccharomyces cerevisiae. The mechanism of protein synthesis is well conserved between yeast and other eukaryotes, and molecular genetic studies in budding yeast have provided critical insights into the fundamental process of translation as well as its regulation. The review focuses on the initiation and elongation phases of protein synthesis with descriptions of the roles of translation initiation and elongation factors that assist the ribosome in binding the messenger RNA (mRNA), selecting the start codon, and synthesizing the polypeptide. We also examine mechanisms of translational control highlighting the mRNA cap-binding proteins and the regulation of GCN4 and CPA1 mRNAs. PMID:27183566

  20. Direct Regulation of Mitochondrial RNA Synthesis by Thyroid Hormone

    PubMed Central

    Enríquez, José A.; Fernández-Silva, Patricio; Garrido-Pérez, Nuria; López-Pérez, Manuel J.; Pérez-Martos, Acisclo; Montoya, Julio

    1999-01-01

    We have analyzed the influence of in vivo treatment and in vitro addition of thyroid hormone on in organello mitochondrial DNA (mtDNA) transcription and, in parallel, on the in organello footprinting patterns at the mtDNA regions involved in the regulation of transcription. We found that thyroid hormone modulates mitochondrial RNA levels and the mRNA/rRNA ratio by influencing the transcriptional rate. In addition, we found conspicuous differences between the mtDNA dimethyl sulfate footprinting patterns of mitochondria derived from euthyroid and hypothyroid rats at the transcription initiation sites but not at the mitochondrial transcription termination factor (mTERF) binding region. Furthermore, direct addition of thyroid hormone to the incubation medium of mitochondria isolated from hypothyroid rats restored the mRNA/rRNA ratio found in euthyroid rats as well as the mtDNA footprinting patterns at the transcription initiation area. Therefore, we conclude that the regulatory effect of thyroid hormone on mitochondrial transcription is partially exerted by a direct influence of the hormone on the mitochondrial transcription machinery. Particularly, the influence on the mRNA/rRNA ratio is achieved by selective modulation of the alternative H-strand transcription initiation sites and does not require the previous activation of nuclear genes. These results provide the first functional demonstration that regulatory signals, such as thyroid hormone, that modify the expression of nuclear genes can also act as primary signals for the transcriptional apparatus of mitochondria. PMID:9858589