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Sample records for murine endogenous retroviruses

  1. Mammalian Endogenous Retroviruses.

    PubMed

    Mager, Dixie L; Stoye, Jonathan P

    2015-02-01

    Over 40% of mammalian genomes comprise the products of reverse transcription. Among such retrotransposed sequences are those characterized by the presence of long terminal repeats (LTRs), including the endogenous retroviruses (ERVs), which are inherited genetic elements closely resembling the proviruses formed following exogenous retrovirus infection. Sequences derived from ERVs make up at least 8 to 10% of the human and mouse genomes and range from ancient sequences that predate mammalian divergence to elements that are currently still active. In this chapter we describe the discovery, classification and origins of ERVs in mammals and consider cellular mechanisms that have evolved to control their expression. We also discuss the negative effects of ERVs as agents of genetic disease and cancer and review examples of ERV protein domestication to serve host functions, as in placental development. Finally, we address growing evidence that the gene regulatory potential of ERV LTRs has been exploited multiple times during evolution to regulate genes and gene networks. Thus, although recently endogenized retroviral elements are often pathogenic, those that survive the forces of negative selection become neutral components of the host genome or can be harnessed to serve beneficial roles. PMID:26104559

  2. Identification of BC005512 as a DNA Damage Responsive Murine Endogenous Retrovirus of GLN Family Involved in Cell Growth Regulation

    PubMed Central

    Wu, Yuanfeng; Qi, Xinming; Gong, Likun; Xing, Guozhen; Chen, Min; Miao, Lingling; Yao, Jun; Suzuki, Takayoshi; Furihata, Chie; Luan, Yang; Ren, Jin

    2012-01-01

    Genotoxicity assessment is of great significance in drug safety evaluation, and microarray is a useful tool widely used to identify genotoxic stress responsive genes. In the present work, by using oligonucleotide microarray in an in vivo model, we identified an unknown gene BC005512 (abbreviated as BC, official full name: cDNA sequence BC005512), whose expression in mouse liver was specifically induced by seven well-known genotoxins (GTXs), but not by non-genotoxins (NGTXs). Bioinformatics revealed that BC was a member of the GLN family of murine endogenous retrovirus (ERV). However, the relationship to genotoxicity and the cellular function of GLN are largely unknown. Using NIH/3T3 cells as an in vitro model system and quantitative real-time PCR, BC expression was specifically induced by another seven GTXs, covering diverse genotoxicity mechanisms. Additionally, dose-response and linear regression analysis showed that expression level of BC in NIH/3T3 cells strongly correlated with DNA damage, measured using the alkaline comet assay,. While in p53 deficient L5178Y cells, GTXs could not induce BC expression. Further functional studies using RNA interference revealed that down-regulation of BC expression induced G1/S phase arrest, inhibited cell proliferation and thus suppressed cell growth in NIH/3T3 cells. Together, our results provide the first evidence that BC005512, a member from GLN family of murine ERV, was responsive to DNA damage and involved in cell growth regulation. These findings could be of great value in genotoxicity predictions and contribute to a deeper understanding of GLN biological functions. PMID:22514700

  3. Endogenous Retroviruses and Human Evolution

    PubMed Central

    Lebedev, Yuri; Sverdlov, Eugene

    2002-01-01

    Humans share about 99% of their genomic DNA with chimpanzees and bonobos; thus, the differences between these species are unlikely to be in gene content but could be caused by inherited changes in regulatory systems. Endogenous retroviruses (ERVs) comprise ∼ 5% of the human genome. The LTRs of ERVs contain many regulatory sequences, such as promoters, enhancers, polyadenylation signals and factor-binding sites. Thus, they can influence the expression of nearby human genes. All known human-specific LTRs belong to the HERV-K (human ERV) family, the most active family in the human genome. It is likely that some of these ERVs could have integrated into regulatory regions of the human genome, and therefore could have had an impact on the expression of adjacent genes, which have consequently contributed to human evolution. This review discusses possible functional consequences of ERV integration in active coding regions. PMID:18629260

  4. Restriction by APOBEC3 proteins of endogenous retroviruses with an extracellular life cycle: ex vivo effects and in vivo "traces" on the murine IAPE and human HERV-K elements

    PubMed Central

    Esnault, Cécile; Priet, Stéphane; Ribet, David; Heidmann, Odile; Heidmann, Thierry

    2008-01-01

    Background APOBEC3 cytosine deaminases have been demonstrated to restrict infectivity of a series of retroviruses, with different efficiencies depending on the retrovirus. In addition, APOBEC3 proteins can severely restrict the intracellular transposition of a series of retroelements with a strictly intracellular life cycle, including the murine IAP and MusD LTR-retrotransposons. Results Here we show that the IAPE element, which is the infectious progenitor of the strictly intracellular IAP elements, and the infectious human endogenous retrovirus HERV-K are restricted by both murine and human APOBEC3 proteins in an ex vivo assay for infectivity, with evidence in most cases of strand-specific G-to-A editing of the proviruses, with the expected signatures. In silico analysis of the naturally occurring genomic copies of the corresponding endogenous elements performed on the mouse and human genomes discloses "traces" of APOBEC3-editing, with the specific signature of the murine APOBEC3 and human APOBEC3G enzymes, respectively, and to a variable extent depending on the family member. Conclusion These results indicate that the IAPE and HERV-K elements, which can only replicate via an extracellular infection cycle, have been restricted at the time of their entry, amplification and integration into their target host genomes by definite APOBEC3 proteins, most probably acting in evolution to limit the mutagenic effect of these endogenized extracellular parasites. PMID:18702815

  5. Identification of receptors for pig endogenous retrovirus

    PubMed Central

    Ericsson, Thomas A.; Takeuchi, Yasuhiro; Templin, Christian; Quinn, Gary; Farhadian, Shelli F.; Wood, James C.; Oldmixon, Beth A.; Suling, Kristen M.; Ishii, Jennifer K.; Kitagawa, Yoshinori; Miyazawa, Takayuki; Salomon, Daniel R.; Weiss, Robin A.; Patience, Clive

    2003-01-01

    Xenotransplantation of porcine tissues has the potential to treat a wide variety of major health problems including organ failure and diabetes. Balanced against the potential benefits of xenotransplantation, however, is the risk of human infection with a porcine microorganism. In particular, the transmission of porcine endogenous retrovirus (PERV) is a major concern [Chapman, L. E. & Bloom, E. T. (2001) J. Am. Med. Assoc. 285, 2304–2306]. Here we report the identification of two, sequence-related, human proteins that act as receptors for PERV-A, encoded by genes located on chromosomes 8 and 17. We also describe homologs from baboon and porcine cells that also are active as receptors. Conversely, activity could not be demonstrated with a syntenic murine receptor homolog. Sequence analysis indicates that PERV-A receptors [human PERV-A receptor (HuPAR)-1, HuPAR-2, baboon PERV-A receptor 2, and porcine PERV-A receptor] are multiple membrane-spanning proteins similar to receptors for other gammaretroviruses. Expression is widespread in human tissues including peripheral blood mononuclear cells, but their biological functions are unknown. The identification of the PERV-A receptors opens avenues of research necessary for a more complete assessment of the retroviral risks of pig to human xenotransplantation. PMID:12740431

  6. Endogenous retroviruses and the development of cancer

    PubMed Central

    Kassiotis, George

    2013-01-01

    Mammalian genomes include a considerable number of endogenous retroviruses (ERVs), relics of ancestral infectious retroviruses, whose proviruses have invaded the germ-line. The documented ability of infectious retroviruses to cause cancer has greatly contributed to the discovery of ERVs. It also reinforced the concept that ERVs are causative agents of many cancers, a notion that historically has not always stood up to experimental scrutiny. The recent greater appreciation of the complexity of ERV biology and the identification of dedicated host mechanisms controlling ERV activity have revealed novel interactions between ERVs and their hosts with the potential to cause or contribute to disease. In this review, the involvement of ERVs in cancer initiation and progression is discussed, as well as their contribution to our understanding of the process of transformation and to the invention of innovative preventive and therapeutic cancer treatments. PMID:24511094

  7. [Endogenous retroviruses are associated with autoimmune diseases].

    PubMed

    Nexø, Bjørn A; Jensen, Sara B; Hansen, Bettina; Laska, Magdalena J

    2016-06-13

    Retroviruses can be transmitted in two fundamentally different ways: 1) They can be horizontally transmitted as infectious virus, or 2) they can integrate in the germ line and be transmitted to offspring and the offsprings' offspring as DNA. The latter is called endogenous viruses. The mode of transmission is called vertical. Viral variants of importance for development of disease must be more frequent among diseased persons than among healthy individuals. Multiple sclerosis, diabetes and rheumatoid arthritis are all associated with sets of endogenouos retroviruses but not the same sets. If a virus grows and this contributes to disease, one should be able to alleviate disease with antiretroviral drugs. We call for clinical trials to elucidate this issue. PMID:27292833

  8. Methylated DNA Immunoprecipitation Analysis of Mammalian Endogenous Retroviruses.

    PubMed

    Rebollo, Rita; Mager, Dixie L

    2016-01-01

    Endogenous retroviruses are repetitive sequences found abundantly in mammalian genomes which are capable of modulating host gene expression. Nevertheless, most endogenous retrovirus copies are under tight epigenetic control via histone-repressive modifications and DNA methylation. Here we describe a common method used in our laboratory to detect, quantify, and compare mammalian endogenous retrovirus DNA methylation. More specifically we describe methylated DNA immunoprecipitation (MeDIP) followed by quantitative PCR. PMID:26895065

  9. Distribution of Endogenous Retroviruses in Crocodilians▿

    PubMed Central

    Jaratlerdsiri, Weerachai; Rodríguez-Zárate, Clara J.; Isberg, Sally R.; Damayanti, Chandramaya Siska; Miles, Lee G.; Chansue, Nantarika; Moran, Chris; Melville, Lorna; Gongora, Jaime

    2009-01-01

    Knowledge of endogenous retroviruses (ERVs) in crocodilians (Crocodylia) is limited, and their distribution among extant species is unclear. Here we analyzed the phylogenetic relationships of these retroelements in 20 species of crocodilians by studying the pro-pol gene. The results showed that crocodilian ERVs (CERVs) cluster into two major clades (CERV 1 and CERV 2). CERV 1 clustered as a sister group of the genus Gammaretrovirus, while CERV 2 clustered distantly with respect to all known ERVs. Interestingly, CERV 1 was found only in crocodiles (Crocodylidae). The data generated here could assist future studies aimed at identifying orthologous and paralogous ERVs among crocodilians. PMID:19605486

  10. Human endogenous retroviruses in neurologic disease.

    PubMed

    Christensen, Tove

    2016-01-01

    Endogenous retroviruses are pathogenic - in other species than the human. Disease associations for Human Endogenous RetroViruses (HERVs) are emerging, but so far an unequivocal pathogenetic cause-effect relationship has not been established. A role for HERVs has been proposed in neurological and neuropsychiatric diseases as diverse as multiple sclerosis (MS) and schizophrenia (SCZ). Particularly for MS, many aspects of the activation and involvement of specific HERV families (HERV-H/F and HERV-W/MSRV) have been reported, both for cells in the circulation and in the central nervous system. Notably envelope genes and their gene products (Envs) appear strongly associated with the disease. For SCZ, for ALS, and for HIV-associated dementia (HAD), indications are accumulating for involvement of the HERV-K family, and also HERV-H/F and/or HERV-W. Activation is reasonably a prerequisite for causality as most HERV sequences remain quiescent in non-pathological conditions, so the importance of regulatory pathways and epigenetics involved in regulating HERV activation, derepression, and also involvement of retroviral restriction factors, is emerging. HERV-directed antiretrovirals have potential as novel therapeutic paradigms in neurologic disease, particularly in MS. The possible protective or ameliorative effects of antiretroviral therapy in MS are substantiated by reports that treatment of HIV infection may be associated with a significantly decreased risk of MS. Further studies of HERVs, their role in neurologic diseases, and their potential as therapeutic targets are essential. PMID:26818266

  11. Endogenous retroviruses and human cancer: is there anything to the rumors?

    PubMed

    Bhardwaj, Neeru; Coffin, John M

    2014-03-12

    Xenotropic murine leukemia virus-related virus (XMRV) infection was incorrectly associated with prostate cancer and chronic fatigue syndrome (CFS) in recent years. In this forum, we discuss the story of XMRV and how we can apply lessons learned here to inform the debate surrounding cancers associated with human endogenous retroviruses (HERVs). PMID:24629332

  12. How Active Are Porcine Endogenous Retroviruses (PERVs)?

    PubMed Central

    Denner, Joachim

    2016-01-01

    Porcine endogenous retroviruses (PERVs) represent a risk factor if porcine cells, tissues, or organs were to be transplanted into human recipients to alleviate the shortage of human transplants; a procedure called xenotransplantation. In contrast to human endogenous retroviruses (HERVs), which are mostly defective and not replication-competent, PERVs are released from normal pig cells and are infectious. PERV-A and PERV-B are polytropic viruses infecting cells of several species, among them humans; whereas PERV-C is an ecotropic virus infecting only pig cells. Virus infection was shown in co-culture experiments, but also in vivo, in the pig, leading to de novo integration of proviruses in certain organs. This was shown by measurement of the copy number per cell, finding different numbers in different organs. In addition, recombinations between PERV-A and PERV-C were observed and the recombinant PERV-A/C were found to be integrated in cells of different organs, but not in the germ line of the animals. Here, the evidence for such in vivo activities of PERVs, including expression as mRNA, protein and virus particles, de novo infection and recombination, will be summarised. These activities make screening of pigs for provirus number and PERV expression level difficult, especially when only blood or ear biopsies are available for analysis. Highly sensitive methods to measure the copy number and the expression level will be required when selecting pigs with low copy number and low expression of PERV as well as when inactivating PERVs using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease (CRISPR/Cas) technology. PMID:27527207

  13. tirant, a newly discovered active endogenous retrovirus in Drosophila simulans.

    PubMed

    Akkouche, Abdou; Rebollo, Rita; Burlet, Nelly; Esnault, Caroline; Martinez, Sonia; Viginier, Barbara; Terzian, Christophe; Vieira, Cristina; Fablet, Marie

    2012-04-01

    Endogenous retroviruses have the ability to become permanently integrated into the genomes of their host, and they are generally transmitted vertically from parent to progeny. With the exception of gypsy, few endogenous retroviruses have been identified in insects. In this study, we describe the tirant endogenous retrovirus in a subset of Drosophila simulans natural populations. By focusing on the envelope gene, we show that the entire retroviral cycle (transcription, translation, and retrotransposition) can be completed for tirant within one population of this species. PMID:22278247

  14. tirant, a Newly Discovered Active Endogenous Retrovirus in Drosophila simulans

    PubMed Central

    Akkouche, Abdou; Rebollo, Rita; Burlet, Nelly; Esnault, Caroline; Martinez, Sonia; Viginier, Barbara; Terzian, Christophe; Vieira, Cristina

    2012-01-01

    Endogenous retroviruses have the ability to become permanently integrated into the genomes of their host, and they are generally transmitted vertically from parent to progeny. With the exception of gypsy, few endogenous retroviruses have been identified in insects. In this study, we describe the tirant endogenous retrovirus in a subset of Drosophila simulans natural populations. By focusing on the envelope gene, we show that the entire retroviral cycle (transcription, translation, and retrotransposition) can be completed for tirant within one population of this species. PMID:22278247

  15. Genome Structure and Thymic Expression of an Endogenous Retrovirus in Zebrafish

    PubMed Central

    Shen, Ching-Hung; Steiner, Lisa A.

    2004-01-01

    In a search for previously unknown genes that are required for lymphocyte development in zebrafish, a retroviral sequence was identified in a subtracted thymus cDNA library and in genomic DNA libraries. The provirus is 11.2 kb and contains intact open reading frames for the gag, pol, and env genes, as well as nearly identical flanking long terminal repeat sequences. As determined by in situ hybridization, the thymus appears to be a major tissue for retroviral expression in both larval and adult fish. Several viral transcripts were found by Northern blotting in the adult thymus. The provirus was found at the same genomic locus in sperm from four fish, suggesting that it is an endogenous retrovirus. Phylogenetic analysis indicates that it is closest to, yet distinct from, the cluster of murine leukemia virus-related retroviruses, suggesting that this virus represents a new group of retroviruses. PMID:14694121

  16. Endogenous retroviruses: acquisition, amplification and taming of genome invaders.

    PubMed

    Dewannieux, Marie; Heidmann, Thierry

    2013-12-01

    Endogenous retroviruses are interspersed genomic elements that were generated after infectious retroviruses entered the germline of their host. They were initially identified as degenerate remnants of past infections, but new models of very recent or ongoing endogenisation are now emerging, allowing the real time investigation of the first steps of the coexistence between these elements and their host. Domestication of endogenous retroviruses involves several mechanisms, including transcriptional control of these elements and regulation of their mobility through the action of restriction factors. Recent studies also point towards an until-now unexpected role of the immune system for the control of these elements, even those that do not contain fully infectious copies. PMID:24004725

  17. The left half of the XMRV retrovirus is present in an endogenous retrovirus of NIH/3T3 Swiss mouse cells.

    PubMed

    Mendoza, Ramon; Vaughan, Andrew E; Miller, A Dusty

    2011-09-01

    Xenotropic murine leukemia virus-related virus (XMRV) is a gammaretrovirus found in association with human prostate cancer and chronic fatigue syndrome, although these associations are controversial. XMRV shows at most 94% identity to known mouse retroviruses. Here we used XMRV-specific PCR to search for a more closely related source of XMRV in mice. While we could not find a complete copy, we did find a 3,600-bp region of XMRV in an endogenous retrovirus present in NIH/3T3 cells. These results show that XMRV has clear ancestors in mice and highlight another possible source of contamination in PCR assays for XMRV. PMID:21697491

  18. Mouse annexin V genomic organization includes an endogenous retrovirus.

    PubMed Central

    Rodriguez-Garcia, M I; Morgan, R O; Fernandez, M R; Bances, P; Fernandez, M P

    1999-01-01

    Mouse annexin V genomic clones were characterized by restriction analysis, Southern blotting and DNA sequencing. The entire gene spans close to 50 kb of the mouse genome and contains 14 exons ranging in size from 31 bp for exon 2 to 482 bp for exon 13 up to the polyadenylation site. Intron sizes range from 111 bp for intron 1b to more than 17 kb for intron 2. Non-coding exon 1 is present in two alternative forms separated by approx. 7.4 kb, and the two promoters associated with exons 1a and 1b are quite distinct. The upstream promoter has a TATA box and may direct the limited, tissue-specific expression of mRNA transcripts containing exon 1a. The downstream, TATA-less promoter has high G+C content, and exon 1b predominates among abundantly expressed mRNA species. The conservation of certain cis-elements, including Sp1, AP2, gamma-IRE and NF-IL6, in orthologous species of annexin V genes points to their possible role in trans-acting protein factor binding and gene regulation. Primer-extension analysis revealed multiple origins for transcription, with principal start sites 100-150 bp upstream of the ATG start codon in exon 2. Intron 4 was longer than that previously identified in the orthologous rat gene due to the integration of an apparently complete copy of the murine endogenous retrovirus element, MuERV-L. Phylogenetic analysis of annexin V from 12 species and the presence of neighbouring loci with paralogous counterparts linked to annexin VI pointed to the common ancestry of these genes via chromosomal duplication more than 600 million years ago. PMID:9854034

  19. Molecular characterization of full-length MLV-related endogenous retrovirus ChiRV1 from the chicken, Gallus gallus.

    PubMed

    Borysenko, Leonid; Stepanets, Volodymir; Rynditch, Alla V

    2008-06-20

    We report the first full-length sequence of an endogenous retrovirus from the genome of domestic chicken, that is not related to the Avian leukemia viruses (ALV). This retrovirus, designated ChiRV1, clusters with Murine leukemia virus (MLV)-related retroviruses and hence is the first complete gammaretrovirus from the genome of a bird. Nevertheless it is not related to exogenous MLV-related retroviruses infecting chicken. The provirus is 9133 bp long and contains 90%-identical LTRs as well as reading frames for the gag, pol and env genes, interrupted by in-frame stop codons. Expression analysis showed that ChiRV1 is a transcribed provirus. Screening of the chicken genome database revealed 100 ChiRV1-related sequences that are grouped into three classes based upon LTR alignment and subsequent phylogenetic analysis. PMID:18440041

  20. Functional Analysis of the env Open Reading Frame in Human Endogenous Retrovirus IDDMK1,222 Encoding Superantigen Activity

    PubMed Central

    Lapatschek, Matthias; Dürr, Susanne; Löwer, Roswitha; Magin, Christine; Wagner, Hermann; Miethke, Thomas

    2000-01-01

    Mice harbor a family of endogenous retroviruses, the mouse mammary tumor viruses (MMTV), which encode superantigens. These superantigens are responsible for the deletion of T cells expressing certain Vβ chains of the T-cell receptor in the thymus. Human T cells are able to recognize MMTV-encoded superantigens presented by human major histocompatibility complex class II-positive cells. Owing to this and to the similarity of the human and murine immune systems, it was speculated that human endogenous retroviruses might also code for superantigens. Recently, it was reported that a proviral clone (IDDMK1,222) of the human endogenous retrovirus family HTDV/HERV-K encodes a superantigen. The putative superantigen gene was located within the env region of the virus. Stimulated by these findings, we amplified by PCR and cloned into eucaryotic expression vectors open reading frames (ORFs) which were identical or very similar to IDDMK1,222. When we transfected these vectors into A20 cells, a murine B-cell lymphoma, we were able to demonstrate mRNA expression and protein production. However, we did not find any evidence that the ORF stimulated human or murine T cells in a Vβ-specific fashion, the most prominent feature of superantigens. PMID:10864649

  1. Mouse retrovirus mediates porcine endogenous retrovirus transmission into human cells in long-term human-porcine chimeric mice

    PubMed Central

    Yang, Yong-Guang; Wood, James C.; Lan, Ping; Wilkinson, Robert A.; Sykes, Megan; Fishman, Jay A.; Patience, Clive

    2004-01-01

    Porcine endogenous retrovirus (PERV) is a potential pathogen in clinical xenotransplantation; transmission of PERV in vivo has been suggested in murine xenotransplantation models. We analyzed the transmission of PERV to human cells in vivo using a model in which immunodeficient NOD/SCID transgenic mice were transplanted with porcine and human lymphohematopoietic tissues. Our results demonstrate, we believe for the first time, that human and pig cells can coexist long-term (up to 25 weeks) without direct PERV infection of human cells. Despite the transplantation of porcine cells that did not produce human-tropic PERV, human cells from the chimeric mice were frequently found to contain PERV sequences. However, this transmission was due to the pseudotyping of PERV-C (a virus without human tropism) by xenotropic murine leukemia virus, rather than to de novo generation of human-tropic PERV. Thus, pseudotyping might account for the PERV transmission previously observed in mice. The absence of direct human cell infection following long-term in vivo coexistence with large numbers of porcine cells provides encouragement regarding the potential safety of using pigs that do not produce human-tropic PERV as source animals for transplantation to humans. PMID:15343388

  2. Infection Barriers to Successful Xenotransplantation Focusing on Porcine Endogenous Retroviruses

    PubMed Central

    Tönjes, Ralf R.

    2012-01-01

    Summary: Xenotransplantation may be a solution to overcome the shortage of organs for the treatment of patients with organ failure, but it may be associated with the transmission of porcine microorganisms and the development of xenozoonoses. Whereas most microorganisms may be eliminated by pathogen-free breeding of the donor animals, porcine endogenous retroviruses (PERVs) cannot be eliminated, since these are integrated into the genomes of all pigs. Human-tropic PERV-A and -B are present in all pigs and are able to infect human cells. Infection of ecotropic PERV-C is limited to pig cells. PERVs may adapt to host cells by varying the number of LTR-binding transcription factor binding sites. Like all retroviruses, they may induce tumors and/or immunodeficiencies. To date, all experimental, preclinical, and clinical xenotransplantations using pig cells, tissues, and organs have not shown transmission of PERV. Highly sensitive and specific methods have been developed to analyze the PERV status of donor pigs and to monitor recipients for PERV infection. Strategies have been developed to prevent PERV transmission, including selection of PERV-C-negative, low-producer pigs, generation of an effective vaccine, selection of effective antiretrovirals, and generation of animals transgenic for a PERV-specific short hairpin RNA inhibiting PERV expression by RNA interference. PMID:22491774

  3. TDP-43 regulates endogenous retrovirus-K viral protein accumulation.

    PubMed

    Manghera, Mamneet; Ferguson-Parry, Jennifer; Douville, Renée N

    2016-10-01

    The concomitant expression of neuronal TAR DNA binding protein 43 (TDP-43) and human endogenous retrovirus-K (ERVK) is a hallmark of ALS. Since the involvement of TDP-43 in retrovirus replication remains controversial, we sought to evaluate whether TDP-43 exerts an effect on ERVK expression. In this study, TDP-43 bound the ERVK promoter in the context of inflammation or proteasome inhibition, with no effect on ERVK transcription. However, over-expression of ALS-associated aggregating forms of TDP-43, but not wild-type TDP-43, significantly enhanced ERVK viral protein accumulation. Human astrocytes and neurons further demonstrated cell-type specific differences in their ability to express and clear ERVK proteins during inflammation and proteasome inhibition. Astrocytes, but not neurons, were able to clear excess ERVK proteins through stress granule formation and autophagy. In vitro findings were validated in autopsy motor cortex tissue from patients with ALS and neuro-normal controls. We further confirmed marked enhancement of ERVK in cortical neurons of patients with ALS. Despite evidence of enhanced stress granule and autophagic response in ALS cortical neurons, these cells failed to clear excess ERVK protein accumulation. This highlights how multiple cellular pathways, in conjunction with disease-associated mutations, can converge to modulate the expression and clearance of viral gene products from genomic elements such as ERVK. In ALS, ERVK protein aggregation is a novel aspect of TDP-43 misregulation contributing towards the pathology of this neurodegenerative disease. PMID:27370226

  4. Unique spectrum of activity of prosimian TRIM5alpha against exogenous and endogenous retroviruses.

    PubMed

    Rahm, Nadia; Yap, Melvyn; Snoeck, Joke; Zoete, Vincent; Muñoz, Miguel; Radespiel, Ute; Zimmermann, Elke; Michielin, Olivier; Stoye, Jonathan P; Ciuffi, Angela; Telenti, Amalio

    2011-05-01

    Lentiviruses, the genus of retrovirus that includes HIV-1, rarely endogenize. Some lemurs uniquely possess an endogenous lentivirus called PSIV ("prosimian immunodeficiency virus"). Thus, lemurs provide the opportunity to study the activity of host defense factors, such as TRIM5α, in the setting of germ line invasion. We characterized the activities of TRIM5α proteins from two distant lemurs against exogenous retroviruses and a chimeric PSIV. TRIM5α from gray mouse lemur, which carries PSIV in its genome, exhibited the narrowest restriction activity. One allelic variant of gray mouse lemur TRIM5α restricted only N-tropic murine leukemia virus (N-MLV), while a second variant restricted N-MLV and, uniquely, B-tropic MLV (B-MLV); both variants poorly blocked PSIV. In contrast, TRIM5α from ring-tailed lemur, which does not contain PSIV in its genome, revealed one of the broadest antiviral activities reported to date against lentiviruses, including PSIV. Investigation into the antiviral specificity of ring-tailed lemur TRIM5α demonstrated a major contribution of a 32-amino-acid expansion in variable region 2 (v2) of the B30.2/SPRY domain to the breadth of restriction. Data on lemur TRIM5α and the prediction of ancestral simian sequences hint at an evolutionary scenario where antiretroviral specificity is prominently defined by the lineage-specific expansion of the variable loops of B30.2/SPRY. PMID:21345948

  5. Genome-wide inactivation of porcine endogenous retroviruses (PERVs).

    PubMed

    Yang, Luhan; Güell, Marc; Niu, Dong; George, Haydy; Lesha, Emal; Grishin, Dennis; Aach, John; Shrock, Ellen; Xu, Weihong; Poci, Jürgen; Cortazio, Rebeca; Wilkinson, Robert A; Fishman, Jay A; Church, George

    2015-11-27

    The shortage of organs for transplantation is a major barrier to the treatment of organ failure. Although porcine organs are considered promising, their use has been checked by concerns about the transmission of porcine endogenous retroviruses (PERVs) to humans. Here we describe the eradication of all PERVs in a porcine kidney epithelial cell line (PK15). We first determined the PK15 PERV copy number to be 62. Using CRISPR-Cas9, we disrupted all copies of the PERV pol gene and demonstrated a >1000-fold reduction in PERV transmission to human cells, using our engineered cells. Our study shows that CRISPR-Cas9 multiplexability can be as high as 62 and demonstrates the possibility that PERVs can be inactivated for clinical application of porcine-to-human xenotransplantation. PMID:26456528

  6. Human Endogenous Retrovirus Group E and Its Involvement in Diseases

    PubMed Central

    Le Dantec, Christelle; Vallet, Sophie; Brooks, Wesley H.; Renaudineau, Yves

    2015-01-01

    Human endogenous retrovirus group E (HERV-E) elements are stably integrated into the human genome, transmitted vertically in a Mendelian manner, and are endowed with transcriptional activity as alternative promoters or enhancers. Such effects are under the control of the proviral long terminal repeats (LTR) that are organized into three HERV-E phylogenetic subgroups, namely LTR2, LTR2B, and LTR2C. Moreover, HERV-E expression is tissue-specific, and silenced by epigenetic constraints that may be disrupted in cancer, autoimmunity, and human placentation. Interest in HERV-E with regard to these conditions has been stimulated further by concerns regarding the capacity of HERV-E elements to modify the expression of neighboring genes and/or to produce retroviral proteins, including immunosuppressive env peptides, which in turn may induce (auto)-antibody (Ab) production. Finally, better understanding of HERV-E elements may have clinical applications for prevention, diagnosis, prognosis, and therapy. PMID:25785516

  7. Generation of neutralising antibodies against porcine endogenous retroviruses (PERVs)

    SciTech Connect

    Kaulitz, Danny; Fiebig, Uwe; Eschricht, Magdalena; Wurzbacher, Christian; Kurth, Reinhard; Denner, Joachim

    2011-03-01

    Antibodies neutralising porcine endogenous retroviruses (PERVs) were induced in different animal species by immunisation with the transmembrane envelope protein p15E. These antibodies recognised epitopes, designated E1, in the fusion peptide proximal region (FPPR) of p15E, and E2 in the membrane proximal external region (MPER). E2 is localised in a position similar to that of an epitope in the transmembrane envelope protein gp41 of the human immunodeficiency virus-1 (HIV-1), recognised by the monoclonal antibody 4E10 that is broadly neutralising. To detect neutralising antibodies specific for PERV, a novel assay was developed, which is based on quantification of provirus integration by real-time PCR. In addition, for the first time, highly effective neutralising antibodies were obtained by immunisation with the surface envelope protein of PERV. These data indicate that neutralising antibodies can be induced by immunisation with both envelope proteins.

  8. Infection of Nonhuman Primate Cells by Pig Endogenous Retrovirus

    PubMed Central

    Blusch, Juergen H.; Patience, Clive; Takeuchi, Yasuhiro; Templin, Christian; Roos, Christian; Von Der Helm, Klaus; Steinhoff, Gustav; Martin, Ulrich

    2000-01-01

    The ongoing shortage of human donor organs for transplantation has catalyzed new interest in the application of pig organs (xenotransplantation). One of the biggest concerns about the transplantation of porcine grafts into humans is the transmission of pig endogenous retroviruses (PERV) to the recipients or even to other members of the community. Although nonhuman primate models are excellently suited to mimic clinical xenotransplantation settings, their value for risk assessment of PERV transmission at xenotransplantation is questionable since all of the primate cell lines tested so far have been found to be nonpermissive for PERV infection. Here we demonstrate that human, gorilla, and Papio hamadryas primary skin fibroblasts and also baboon B-cell lines are permissive for PERV infection. This suggests that a reevaluation of the suitability of the baboon model for risk assessment in xenotransplantation is critical at this point. PMID:10906227

  9. The role of human endogenous retroviruses in brain development and function.

    PubMed

    Mortelmans, Kristien; Wang-Johanning, Feng; Johanning, Gary L

    2016-01-01

    Endogenous retroviral sequences are spread throughout the genome of all humans, and make up about 8% of the genome. Despite their prevalence, the function of human endogenous retroviruses (HERVs) in humans is largely unknown. In this review we focus on the brain, and evaluate studies in animal models that address mechanisms of endogenous retrovirus activation in the brain and central nervous system (CNS). One such study in mice found that TRIM28, a protein critical for mouse early development, regulates transcription and silencing of endogenous retroviruses in neural progenitor cells. Another intriguing finding in human brain cells and mouse models was that endogenous retrovirus HERV-K appears to be protective against neurotoxins. We also report on studies that associate HERVs with human diseases of the brain and CNS. There is little doubt of an association between HERVs and a number of CNS diseases. However, a cause and effect relationship between HERVs and these diseases has not yet been established. PMID:26818265

  10. A paradigm for virus-host coevolution: Sequential counter-adaptations between endogenous and exogenous retroviruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that during evolution some ERVs were used by the host to drive extinction of exogenous horizontally-transmitted retroviruses. Se...

  11. Infectivity and insertional mutagenesis of endogenous retrovirus in autoimmune NZB and B/W mice.

    PubMed

    Beck-Engeser, Gabriele B; Ahrends, Tomasz; Knittel, Gero; Wabl, Rafael; Metzner, Mirjam; Eilat, Dan; Wabl, Matthias

    2015-11-01

    Murine leukaemia virus has been suggested to contribute to both autoimmune disease and leukaemia in the NZB mouse and in the (NZB × NZW) F1 (abbreviated B/W) mouse. However, with apparently only xenotropic but no ecotropic virus constitutively expressed in these mice, few mechanisms could explain the aetiology of either disease in either mouse strain. Because pseudotyped and/or inducible ecotropic virus may play a role, we surveyed the ability of murine leukaemia virus in NZB, NZW and B/W mice to infect and form a provirus. From the spleen of NZB mice, we isolated circular cDNA of xenotropic and polytropic virus, which indicates ongoing infection by these viruses. From a B/W lymphoma, we isolated and determined the complete sequence of a putative ecotropic NZW virus. From B/W mice, we recovered de novo endogenous retroviral integration sites (tags) from the hyperproliferating cells of the spleen and the peritoneum. The tagged genes seemed to be selected to aid cellular proliferation, as several of them are known cancer genes. The insertions are consistent with the idea that endogenous retrovirus contributes to B-cell hyperproliferation and progression to lymphoma in B/W mice. PMID:26315139

  12. A Paradigm for Virus–Host Coevolution: Sequential Counter-Adaptations between Endogenous and Exogenous Retroviruses

    PubMed Central

    Arnaud, Frederick; Caporale, Marco; Varela, Mariana; Biek, Roman; Chessa, Bernardo; Alberti, Alberto; Golder, Matthew; Mura, Manuela; Zhang, Ya-ping; Yu, Li; Pereira, Filipe; DeMartini, James C; Leymaster, Kreg; Spencer, Thomas E; Palmarini, Massimo

    2007-01-01

    Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous retroviruses (enJSRVs). Here, we isolated and characterized the evolutionary history and molecular virology of 27 enJSRV proviruses. enJSRVs have been integrating in the host genome for the last 5–7 million y. Two enJSRV proviruses (enJS56A1 and enJSRV-20), which entered the host genome within the last 3 million y (before and during speciation within the genus Ovis), acquired in two temporally distinct events a defective Gag polyprotein resulting in a transdominant phenotype able to block late replication steps of related exogenous retroviruses. Both transdominant proviruses became fixed in the host genome before or around sheep domestication (∼ 9,000 y ago). Interestingly, a provirus escaping the transdominant enJSRVs has emerged very recently, most likely within the last 200 y. Thus, we determined sequentially distinct events during evolution that are indicative of an evolutionary antagonism between endogenous and exogenous retroviruses. This study strongly suggests that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections. PMID

  13. A paradigm for virus-host coevolution: sequential counter-adaptations between endogenous and exogenous retroviruses.

    PubMed

    Arnaud, Frederick; Caporale, Marco; Varela, Mariana; Biek, Roman; Chessa, Bernardo; Alberti, Alberto; Golder, Matthew; Mura, Manuela; Zhang, Ya-Ping; Yu, Li; Pereira, Filipe; Demartini, James C; Leymaster, Kreg; Spencer, Thomas E; Palmarini, Massimo

    2007-11-01

    Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous retroviruses (enJSRVs). Here, we isolated and characterized the evolutionary history and molecular virology of 27 enJSRV proviruses. enJSRVs have been integrating in the host genome for the last 5-7 million y. Two enJSRV proviruses (enJS56A1 and enJSRV-20), which entered the host genome within the last 3 million y (before and during speciation within the genus Ovis), acquired in two temporally distinct events a defective Gag polyprotein resulting in a transdominant phenotype able to block late replication steps of related exogenous retroviruses. Both transdominant proviruses became fixed in the host genome before or around sheep domestication (approximately 9,000 y ago). Interestingly, a provirus escaping the transdominant enJSRVs has emerged very recently, most likely within the last 200 y. Thus, we determined sequentially distinct events during evolution that are indicative of an evolutionary antagonism between endogenous and exogenous retroviruses. This study strongly suggests that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections

  14. Discovery of unfixed endogenous retrovirus insertions in diverse human populations.

    PubMed

    Wildschutte, Julia Halo; Williams, Zachary H; Montesion, Meagan; Subramanian, Ravi P; Kidd, Jeffrey M; Coffin, John M

    2016-04-19

    Endogenous retroviruses (ERVs) have contributed to more than 8% of the human genome. The majority of these elements lack function due to accumulated mutations or internal recombination resulting in a solitary (solo) LTR, although members of one group of human ERVs (HERVs), HERV-K, were recently active with members that remain nearly intact, a subset of which is present as insertionally polymorphic loci that include approximately full-length (2-LTR) and solo-LTR alleles in addition to the unoccupied site. Several 2-LTR insertions have intact reading frames in some or all genes that are expressed as functional proteins. These properties reflect the activity of HERV-K and suggest the existence of additional unique loci within humans. We sought to determine the extent to which other polymorphic insertions are present in humans, using sequenced genomes from the 1000 Genomes Project and a subset of the Human Genome Diversity Project panel. We report analysis of a total of 36 nonreference polymorphic HERV-K proviruses, including 19 newly reported loci, with insertion frequencies ranging from <0.0005 to >0.75 that varied by population. Targeted screening of individual loci identified three new unfixed 2-LTR proviruses within our set, including an intact provirus present at Xq21.33 in some individuals, with the potential for retained infectivity. PMID:27001843

  15. Human endogenous retrovirus-K contributes to motor neuron disease.

    PubMed

    Li, Wenxue; Lee, Myoung-Hwa; Henderson, Lisa; Tyagi, Richa; Bachani, Muzna; Steiner, Joseph; Campanac, Emilie; Hoffman, Dax A; von Geldern, Gloria; Johnson, Kory; Maric, Dragan; Morris, H Douglas; Lentz, Margaret; Pak, Katherine; Mammen, Andrew; Ostrow, Lyle; Rothstein, Jeffrey; Nath, Avindra

    2015-09-30

    The role of human endogenous retroviruses (HERVs) in disease pathogenesis is unclear. We show that HERV-K is activated in a subpopulation of patients with sporadic amyotrophic lateral sclerosis (ALS) and that its envelope (env) protein may contribute to neurodegeneration. The virus was expressed in cortical and spinal neurons of ALS patients, but not in neurons from control healthy individuals. Expression of HERV-K or its env protein in human neurons caused retraction and beading of neurites. Transgenic animals expressing the env gene developed progressive motor dysfunction accompanied by selective loss of volume of the motor cortex, decreased synaptic activity in pyramidal neurons, dendritic spine abnormalities, nucleolar dysfunction, and DNA damage. Injury to anterior horn cells in the spinal cord was manifested by muscle atrophy and pathological changes consistent with nerve fiber denervation and reinnervation. Expression of HERV-K was regulated by TAR (trans-activation responsive) DNA binding protein 43, which binds to the long terminal repeat region of the virus. Thus, HERV-K expression within neurons of patients with ALS may contribute to neurodegeneration and disease pathogenesis. PMID:26424568

  16. Porcine Endogenous Retroviruses in Xenotransplantation—Molecular Aspects

    PubMed Central

    Kimsa, Magdalena C.; Strzalka-Mrozik, Barbara; Kimsa, Malgorzata W.; Gola, Joanna; Nicholson, Peter; Lopata, Krzysztof; Mazurek, Urszula

    2014-01-01

    In the context of the shortage of organs and other tissues for use in human transplantation, xenotransplantation procedures with material taken from pigs have come under increased consideration. However, there are unclear consequences of the potential transmission of porcine pathogens to humans. Of particular concern are porcine endogenous retroviruses (PERVs). Three subtypes of PERV have been identified, of which PERV-A and PERV-B have the ability to infect human cells in vitro. The PERV-C subtype does not show this ability but recombinant PERV-A/C forms have demonstrated infectivity in human cells. In view of the risk presented by these observations, the International Xenotransplantation Association recently indicated the existence of four strategies to prevent transmission of PERVs. This article focuses on the molecular aspects of PERV infection in xenotransplantation and reviews the techniques available for the detection of PERV DNA, RNA, reverse transcriptase activity and proteins, and anti-PERV antibodies to enable carrying out these recommendations. These methods could be used to evaluate the risk of PERV transmission in human recipients, enhance the effectiveness and reliability of monitoring procedures, and stimulate discussion on the development of improved, more sensitive methods for the detection of PERVs in the future. PMID:24828841

  17. ERV-L Elements: a Family of Endogenous Retrovirus-Like Elements Active throughout the Evolution of Mammals

    PubMed Central

    Bénit, Laurence; Lallemand, Jean-Baptiste; Casella, Jean-François; Philippe, Hervé; Heidmann, Thierry

    1999-01-01

    We have previously identified in the human genome a family of 200 endogenous retrovirus-like elements, the HERV-L elements, disclosing similarities with the foamy retroviruses and which might be the evolutionary intermediate between classical intracellular retrotransposons and infectious retroviruses. Southern blot analysis of a large series of mammalian genomic DNAs shows that HERV-L-related elements—so-called ERV-L—are present among all placental mammals, suggesting that ERV-L elements were already present at least 70 million years ago. Most species exhibit a low copy number of ERV-L elements (from 10 to 30), while simians (not prosimians) and mice (not rats) have been subjected to bursts resulting in increases in the number of copies up to 200. The burst of copy number in primates can be dated to shortly after the prosimian and simian branchpoint, 45 to 65 million years ago, whereas murine species have been subjected to two much more recent bursts (less than 10 million years ago), occurring after the Mus/Rattus split. We have amplified and sequenced 360-bp ERV-L internal fragments of the highly conserved pol gene from a series of 22 mammalian species. These sequences exhibit high percentages of identity (57 to 99%) with the murine fully coding MuERV-L element. Phylogenetic analyses allowed the establishment of a plausible evolutionary scheme for ERV-L elements, which accounts for the high level of sequence conservation and the widespread dispersion among mammals. PMID:10074184

  18. Epigenetic interplay between mouse endogenous retroviruses and host genes

    PubMed Central

    2012-01-01

    Background Transposable elements are often the targets of repressive epigenetic modifications such as DNA methylation that, in theory, have the potential to spread toward nearby genes and induce epigenetic silencing. To better understand the role of DNA methylation in the relationship between transposable elements and genes, we assessed the methylation state of mouse endogenous retroviruses (ERVs) located near genes. Results We found that ERVs of the ETn/MusD family show decreased DNA methylation when near transcription start sites in tissues where the nearby gene is expressed. ERVs belonging to the IAP family, however, are generally heavily methylated, regardless of the genomic environment and the tissue studied. Furthermore, we found full-length ETn and IAP copies that display differential DNA methylation between their two long terminal repeats (LTRs), suggesting that the environment surrounding gene promoters can prevent methylation of the nearby LTR. Spreading from methylated ERV copies to nearby genes was rarely observed, with the regions between the ERVs and genes apparently acting as a boundary, enriched in H3K4me3 and CTCF, which possibly protects the unmethylated gene promoter. Furthermore, the flanking regions of unmethylated ERV copies harbor H3K4me3, consistent with spreading of euchromatin from the host gene toward ERV insertions. Conclusions We have shown that spreading of DNA methylation from ERV copies toward active gene promoters is rare. We provide evidence that genes can be protected from ERV-induced heterochromatin spreading by either blocking the invasion of repressive marks or by spreading euchromatin toward the ERV copy. PMID:23034137

  19. Evidence and Consequence of Porcine Endogenous Retrovirus Recombination

    PubMed Central

    Bartosch, Birke; Stefanidis, Dimitrios; Myers, Richard; Weiss, Robin; Patience, Clive; Takeuchi, Yasuhiro

    2004-01-01

    The genetic nature and biological effects of recombination between porcine endogenous retroviruses (PERV) were studied. An infectious molecular clone was generated from a high-titer, human-tropic PERV isolate, PERV-A 14/220 (B. A. Oldmixon, et al. J. Virol. 76:3045-3048, 2002; T. A. Ericsson et al. Proc. Natl. Acad. Sci. USA 100:6759-6764, 2003). To analyze this sequence and 15 available full-length PERV nucleotide sequences, we developed a sequence comparison program, LOHATM to calculate local sequence homology between two sequences. This analysis determined that PERV-A 14/220 arose by homologous recombination of a PERV-C genome replacing an 850-bp region around the pol-env junction with that of a PERV-A sequence. This 850-bp PERV-A sequence encompasses the env receptor binding domain, thereby conferring a wide host range including human cells. In addition, we determined that multiple regions derived from PERV-C are responsible for the increased infectious titer of PERV-A 14/220. Thus, a single recombination event may be a fast and effective way to generate high-titer, potentially harmful PERV. Further, local homology and phylogenetic analyses between 16 full-length sequences revealed evidence for other recombination events in the past that give rise to other PERV genomes that possess the PERV-A, but not the PERV-B, env gene. These results indicate that PERV-A env is more prone to recombination with heterogeneous backbone genomes than PERV-B env. Such recombination events that generate more active PERV-A appear to occur in pigs rather frequently, which increases the potential risk of zoonotic PERV transmission. In this context, pigs lacking non-human-tropic PERV-C would be more suitable as donor animals for clinical xenotransplantation. PMID:15564496

  20. Human Endogenous Retrovirus Protein Activates Innate Immunity and Promotes Experimental Allergic Encephalomyelitis in Mice

    PubMed Central

    Perron, Hervé; Dougier-Reynaud, Hei-Lanne; Lomparski, Christina; Popa, Iuliana; Firouzi, Reza; Bertrand, Jean-Baptiste; Marusic, Suzana; Portoukalian, Jacques; Jouvin-Marche, Evelyne; Villiers, Christian L.; Touraine, Jean-Louis; Marche, Patrice N.

    2013-01-01

    Multiple sclerosis (MS) is a complex multifactorial disease of the central nervous system (CNS) for which animal models have mainly addressed downstream immunopathology but not potential inducers of autoimmunity. In the absence of a pathogen known to cause neuroinflammation in MS, Mycobacterial lysate is commonly used in the form of complete Freund's adjuvant to induce autoimmunity to myelin proteins in Experimental Allergic Encephalomyelitis (EAE), an animal model for MS. The present study demonstrates that a protein from the human endogenous retrovirus HERV-W family (MSRV-Env) can be used instead of mycobacterial lysate to induce autoimmunity and EAE in mice injected with MOG, with typical anti-myelin response and CNS lesions normally seen in this model. MSRV-Env was shown to induce proinflammatory response in human macrophage cells through TLR4 activation pathway. The present results demonstrate a similar activation of murine dendritic cells and show the ability of MSRV-Env to trigger EAE in mice. In previous studies, MSRV-Env protein was reproducibly detected in MS brain lesions within microglia and perivascular macrophages. The present results are therefore likely to provide a model for MS, in which the upstream adjuvant triggering neuroinflammation is the one detected in MS active lesions. This model now allows pre-clinical studies with therapeutic agents targeting this endogenous retroviral protein in MS. PMID:24324591

  1. In between: Gypsy in Drosophila melanogaster Reveals New Insights into Endogenous Retrovirus Evolution

    PubMed Central

    Touret, Franck; Guiguen, François; Greenland, Timothy; Terzian, Christophe

    2014-01-01

    Retroviruses are RNA viruses that are able to synthesize a DNA copy of their genome and insert it into a chromosome of the host cell. Sequencing of different eukaryote genomes has revealed the presence of many such endogenous retroviral sequences. The mechanisms by which these retroviral sequences have colonized the genome are still unknown, and the endogenous retrovirus gypsy of Drosophila melanogaster is a powerful experimental model for deciphering this process in vivo. Gypsy is expressed in a layer of somatic cells, and then transferred into the oocyte by an unknown mechanism. This critical step is the start of the endogenization process. Moreover gypsy has been shown to have infectious properties, probably due to its envelope gene acquired from a baculovirus. Recently we have also shown that gypsy maternal transmission is reduced in the presence of the endosymbiotic bacterium Wolbachia. These studies demonstrate that gypsy is a unique and powerful model for understanding the endogenization of retroviruses. PMID:25502325

  2. Characterizing novel endogenous retroviruses from genetic variation inferred from short sequence reads

    PubMed Central

    Mourier, Tobias; Mollerup, Sarah; Vinner, Lasse; Hansen, Thomas Arn; Kjartansdóttir, Kristín Rós; Guldberg Frøslev, Tobias; Snogdal Boutrup, Torsten; Nielsen, Lars Peter; Willerslev, Eske; Hansen, Anders J.

    2015-01-01

    From Illumina sequencing of DNA from brain and liver tissue from the lion, Panthera leo, and tumor samples from the pike-perch, Sander lucioperca, we obtained two assembled sequence contigs with similarity to known retroviruses. Phylogenetic analyses suggest that the pike-perch retrovirus belongs to the epsilonretroviruses, and the lion retrovirus to the gammaretroviruses. To determine if these novel retroviral sequences originate from an endogenous retrovirus or from a recently integrated exogenous retrovirus, we assessed the genetic diversity of the parental sequences from which the short Illumina reads are derived. First, we showed by simulations that we can robustly infer the level of genetic diversity from short sequence reads. Second, we find that the measures of nucleotide diversity inferred from our retroviral sequences significantly exceed the level observed from Human Immunodeficiency Virus infections, prompting us to conclude that the novel retroviruses are both of endogenous origin. Through further simulations, we rule out the possibility that the observed elevated levels of nucleotide diversity are the result of co-infection with two closely related exogenous retroviruses. PMID:26493184

  3. Characterizing novel endogenous retroviruses from genetic variation inferred from short sequence reads.

    PubMed

    Mourier, Tobias; Mollerup, Sarah; Vinner, Lasse; Hansen, Thomas Arn; Kjartansdóttir, Kristín Rós; Guldberg Frøslev, Tobias; Snogdal Boutrup, Torsten; Nielsen, Lars Peter; Willerslev, Eske; Hansen, Anders J

    2015-01-01

    From Illumina sequencing of DNA from brain and liver tissue from the lion, Panthera leo, and tumor samples from the pike-perch, Sander lucioperca, we obtained two assembled sequence contigs with similarity to known retroviruses. Phylogenetic analyses suggest that the pike-perch retrovirus belongs to the epsilonretroviruses, and the lion retrovirus to the gammaretroviruses. To determine if these novel retroviral sequences originate from an endogenous retrovirus or from a recently integrated exogenous retrovirus, we assessed the genetic diversity of the parental sequences from which the short Illumina reads are derived. First, we showed by simulations that we can robustly infer the level of genetic diversity from short sequence reads. Second, we find that the measures of nucleotide diversity inferred from our retroviral sequences significantly exceed the level observed from Human Immunodeficiency Virus infections, prompting us to conclude that the novel retroviruses are both of endogenous origin. Through further simulations, we rule out the possibility that the observed elevated levels of nucleotide diversity are the result of co-infection with two closely related exogenous retroviruses. PMID:26493184

  4. Human Endogenous Retrovirus and Neuroinflammation in Chronic Inflammatory Demyelinating Polyradiculoneuropathy

    PubMed Central

    Faucard, Raphaël; Madeira, Alexandra; Gehin, Nadège; Authier, François-Jérôme; Panaite, Petrica-Adrian; Lesage, Catherine; Burgelin, Ingrid; Bertel, Mélanie; Bernard, Corinne; Curtin, François; Lang, Aloïs B.; Steck, Andreas J.; Perron, Hervé; Kuntzer, Thierry; Créange, Alain

    2016-01-01

    Background Human endogenous retroviruses HERV-W encode a pro-inflammatory protein, named MSRV-Env from its original identification in Multiple Sclerosis. Though not detected in various neurological controls, MSRV-Env was found in patients with chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs). This study investigated the expression of MSRV in CIDP and evaluated relevant MSRV-Env pathogenic effects. Methods 50 CIDP patients, 19 other neurological controls (ONDs) and 65 healthy blood donors (HBDs) were recruited from two different countries. MSRV-env and -pol transcripts, IL6 and CXCL10 levels were quantified from blood samples. MSRV-Env immunohistology was performed in distal sensory nerves from CIDP and neurological controls biopsies. MSRV-Env pathogenic effects and mode of action were assayed in cultured primary human Schwann cells (HSCs). Findings In both cohorts, MSRV-env and -pol transcripts, IL6 positivity prevalence and CXCL10 levels were significantly elevated in CIDP patients when compared to HBDs and ONDs (statistically significant in all comparisons). MSRV-Env protein was detected in Schwann cells in 5/7 CIDP biopsies. HSC exposed to or transfected with MSRV-env presented a strong increase of IL6 and CXCL10 transcripts and protein secretion. These pathogenic effects on HSC were inhibited by GNbAC1, a highly specific and neutralizing humanized monoclonal antibody targeting MSRV-Env. Interpretation The present study showed that MSRV-Env may trigger the release of critical immune mediators proposed as instrumental factors involved in the pathophysiology of CIDP. Significant MSRV-Env expression was detected in a significant proportion of patients with CIDP, in which it may play a role according to its presently observed effects on Schwann cells along with previously known effects on immune cells. Experimental results also suggest that a biomarker-driven therapeutic strategy targeting this protein with a neutralizing antibody such as GNbAC1

  5. Restriction of Porcine Endogenous Retrovirus by Porcine APOBEC3 Cytidine Deaminases ▿

    PubMed Central

    Dörrschuck, Eva; Fischer, Nicole; Bravo, Ignacio G.; Hanschmann, Kay-Martin; Kuiper, Heidi; Spötter, Andreas; Möller, Ronny; Cichutek, Klaus; Münk, Carsten; Tönjes, Ralf R.

    2011-01-01

    Xenotransplantation of porcine cells, tissues, and organs shows promise to surmount the shortage of human donor materials. Among the barriers to pig-to-human xenotransplantation are porcine endogenous retroviruses (PERV) since functional representatives of the two polytropic classes, PERV-A and PERV-B, are able to infect human embryonic kidney cells in vitro, suggesting that a xenozoonosis in vivo could occur. To assess the capacity of human and porcine cells to counteract PERV infections, we analyzed human and porcine APOBEC3 (A3) proteins. This multigene family of cytidine deaminases contributes to the cellular intrinsic immunity and act as potent inhibitors of retroviruses and retrotransposons. Our data show that the porcine A3 gene locus on chromosome 5 consists of the two single-domain genes A3Z2 and A3Z3. The evolutionary relationships of the A3Z3 genes reflect the evolutionary history of mammals. The two A3 genes encode at least four different mRNAs: A3Z2, A3Z3, A3Z2-Z3, and A3Z2-Z3 splice variant A (SVA). Porcine and human A3s have been tested toward their antiretroviral activity against PERV and murine leukemia virus (MuLV) using novel single-round reporter viruses. The porcine A3Z2, A3Z3 and A3Z2-Z3 were packaged into PERV particles and inhibited PERV replication in a dose-dependent manner. The antiretroviral effect correlated with editing by the porcine A3s with a trinucleotide preference for 5′ TGC for A3Z2 and A3Z2-Z3 and 5′ CAC for A3Z3. These results strongly imply that human and porcine A3s could inhibit PERV replication in vivo, thereby reducing the risk of infection of human cells by PERV in the context of pig-to-human xenotransplantation. PMID:21307203

  6. v-cbl, an oncogene from a dual-recombinant murine retrovirus that induces early B-lineage lymphomas.

    PubMed Central

    Langdon, W Y; Hartley, J W; Klinken, S P; Ruscetti, S K; Morse, H C

    1989-01-01

    Cas NS-1 is an acutely transforming murine retrovirus that induces pre-B and pro-B cell lymphomas. Molecular cloning showed it was generated from the ecotropic Cas-Br-M virus by sequential recombinations with endogenous retroviral sequences and a cellular oncogene. The oncogene sequence shows no homology with known oncogenes but some similarity to the yeast transcriptional activator GCN4. A 100-kDa gag-cbl fusion protein, with no detectable kinase activity, is responsible for the cellular transformation. The cellular homologue of v-cbl, present in mouse and human DNA, is expressed in a range of hemopoietic lineages. Images PMID:2784003

  7. Chemical induction of endogenous retrovirus particles from the vero cell line of African green monkeys.

    PubMed

    Ma, Hailun; Ma, Yunkun; Ma, Wenbin; Williams, Dhanya K; Galvin, Teresa A; Khan, Arifa S

    2011-07-01

    Endogenous retroviral sequences are present in high copy numbers in the genomes of all species and may be expressed as RNAs; however, the majority are defective for virus production. Although virus has been isolated from various Old World monkey and New World monkey species, there has been no report of endogenous retroviruses produced from African green monkey (AGM) tissues or cell lines. We have recently developed a stepwise approach for evaluating the presence of latent viruses by chemical induction (Khan et al., Biologicals 37:196-201, 2009). Based upon this strategy, optimum conditions were determined for investigating the presence of inducible, endogenous retroviruses in the AGM-derived Vero cell line. Low-level reverse transcriptase activity was produced with 5-azacytidine (AzaC) and with 5'-iodo-2'-deoxyuridine (IUdR); none was detected with sodium butyrate. Nucleotide sequence analysis of PCR-amplified fragments from the gag, pol, and env regions of RNAs, prepared from ultracentrifuged pellets of filtered supernatants, indicated that endogenous retrovirus particles related to simian endogenous type D betaretrovirus (SERV) sequences and baboon endogenous virus type C gammaretrovirus (BaEV) sequences were induced by AzaC, whereas SERV sequences were also induced by IUdR. Additionally, sequence heterogeneity was seen in the RNAs of SERV- and BaEV-related particles. Infectivity analysis of drug-treated AGM Vero cells showed no virus replication in cell lines known to be susceptible to type D simian retroviruses (SRVs) and to BaEV. The results indicated that multiple, inducible endogenous retrovirus loci are present in the AGM genome that can encode noninfectious, viruslike particles. PMID:21543506

  8. Chemical Induction of Endogenous Retrovirus Particles from the Vero Cell Line of African Green Monkeys▿

    PubMed Central

    Ma, Hailun; Ma, Yunkun; Ma, Wenbin; Williams, Dhanya K.; Galvin, Teresa A.; Khan, Arifa S.

    2011-01-01

    Endogenous retroviral sequences are present in high copy numbers in the genomes of all species and may be expressed as RNAs; however, the majority are defective for virus production. Although virus has been isolated from various Old World monkey and New World monkey species, there has been no report of endogenous retroviruses produced from African green monkey (AGM) tissues or cell lines. We have recently developed a stepwise approach for evaluating the presence of latent viruses by chemical induction (Khan et al., Biologicals 37:196–201, 2009). Based upon this strategy, optimum conditions were determined for investigating the presence of inducible, endogenous retroviruses in the AGM-derived Vero cell line. Low-level reverse transcriptase activity was produced with 5-azacytidine (AzaC) and with 5′-iodo-2′-deoxyuridine (IUdR); none was detected with sodium butyrate. Nucleotide sequence analysis of PCR-amplified fragments from the gag, pol, and env regions of RNAs, prepared from ultracentrifuged pellets of filtered supernatants, indicated that endogenous retrovirus particles related to simian endogenous type D betaretrovirus (SERV) sequences and baboon endogenous virus type C gammaretrovirus (BaEV) sequences were induced by AzaC, whereas SERV sequences were also induced by IUdR. Additionally, sequence heterogeneity was seen in the RNAs of SERV- and BaEV-related particles. Infectivity analysis of drug-treated AGM Vero cells showed no virus replication in cell lines known to be susceptible to type D simian retroviruses (SRVs) and to BaEV. The results indicated that multiple, inducible endogenous retrovirus loci are present in the AGM genome that can encode noninfectious, viruslike particles. PMID:21543506

  9. Molecular cloning and long terminal repeat sequences of human endogenous retrovirus genes related to types A and B retrovirus genes

    SciTech Connect

    Ono, M.

    1986-06-01

    By using a DNA fragment primarily encoding the reverse transcriptase (pol) region of the Syrian hamster intracisternal A particle (IAP; type A retrovirus) gene as a probe, human endogenous retrovirus genes, tentatively termed HERV-K genes, were cloned from a fetal human liver gene library. Typical HERV-K genes were 9.1 or 9.4 kilobases in length, having long terminal repeats (LTRs) of ca. 970 base pairs. Many structural features commonly observed on the retrovirus LTRs, such as the TATAA box, polyadenylation signal, and terminal inverted repeats, were present on each LTR, and a lysine (K) tRNA having a CUU anticodon was identified as a presumed primer tRNA. The HERV-K LTR, however, had little sequence homology to either the IAP LTR or other typical oncovirus LTRs. By filter hybridization, the number of HERV-K genes was estimated to be ca. 50 copies per haploid human genome. The cloned mouse mammary tumor virus (type B) gene was found to hybridize with both the HERV-K and IAP genes to essentially the same extent.

  10. Host Control of Insect Endogenous Retroviruses: Small RNA Silencing and Immune Response

    PubMed Central

    Fablet, Marie

    2014-01-01

    Endogenous retroviruses are relics of ancient infections from retroviruses that managed to integrate into the genome of germline cells and remained vertically transmitted from parent to progeny. Subsequent to the endogenization process, these sequences can move and multiply in the host genome, which can have deleterious consequences and disturb genomic stability. Natural selection favored the establishment of silencing pathways that protect host genomes from the activity of endogenous retroviruses. RNA silencing mechanisms are involved, which utilize piRNAs. The response to exogenous viral infections uses siRNAs, a class of small RNAs that are generated via a distinct biogenesis pathway from piRNAs. However, interplay between both pathways has been identified, and interactions with anti-bacterial and anti-fungal immune responses are also suspected. This review focuses on Diptera (Arthropods) and intends to compile pieces of evidence showing that the RNA silencing pathway of endogenous retrovirus regulation is not independent from immunity and the response to infections. This review will consider the mechanisms that allow the lasting coexistence of viral sequences and host genomes from an evolutionary perspective. PMID:25412365

  11. Selective Inhibition of Porcine Endogenous Retrovirus Replication in Human Cells by Acyclic Nucleoside Phosphonates▿

    PubMed Central

    Shi, Minyi; Wang, Xin; De Clercq, Erik; Takao, Sonshin; Baba, Masanori

    2007-01-01

    Several anti-human immunodeficiency virus type 1 reverse transcriptase inhibitors were evaluated for their antiviral activities against porcine endogenous retrovirus in human cells. Among the test compounds, zidovudine was found to be the most active. The order of potency was zidovudine > phosphonylmethoxyethoxydiaminopyrimidine = phosphonylmethoxypropyldiaminopurine > tenofovir ≥ adefovir > stavudine. PMID:17470654

  12. Antiretroviral Agents Inhibit Infection of Human Cells by Porcine Endogenous Retroviruses

    PubMed Central

    Powell, S. K.; Gates, M. E.; Langford, G.; Gu, M.-L.; Lockey, C.; Long, Z.; Otto, E.

    2000-01-01

    The efficacy of antiretroviral drugs against porcine endogenous retroviruses (PERV) that may be harbored in pig organs intended for transplantation was examined in human cells in vitro. The nucleoside analogs zidovudine and dideoxyinosine were found to effectively inhibit PERV replication. PMID:11083652

  13. Cross-Species Transmission and Differential Fate of an Endogenous Retrovirus in Three Mammal Lineages

    PubMed Central

    Zhuo, Xiaoyu; Feschotte, Cédric

    2015-01-01

    Endogenous retroviruses (ERVs) arise from retroviruses chromosomally integrated in the host germline. ERVs are common in vertebrate genomes and provide a valuable fossil record of past retroviral infections to investigate the biology and evolution of retroviruses over a deep time scale, including cross-species transmission events. Here we took advantage of a catalog of ERVs we recently produced for the bat Myotis lucifugus to seek evidence for infiltration of these retroviruses in other mammalian species (>100) currently represented in the genome sequence database. We provide multiple lines of evidence for the cross-ordinal transmission of a gammaretrovirus endogenized independently in the lineages of vespertilionid bats, felid cats and pangolin ~13–25 million years ago. Following its initial introduction, the ERV amplified extensively in parallel in both bat and cat lineages, generating hundreds of species-specific insertions throughout evolution. However, despite being derived from the same viral species, phylogenetic and selection analyses suggest that the ERV experienced different amplification dynamics in the two mammalian lineages. In the cat lineage, the ERV appears to have expanded primarily by retrotransposition of a single proviral progenitor that lost infectious capacity shortly after endogenization. In the bat lineage, the ERV followed a more complex path of germline invasion characterized by both retrotransposition and multiple infection events. The results also suggest that some of the bat ERVs have maintained infectious capacity for extended period of time and may be still infectious today. This study provides one of the most rigorously documented cases of cross-ordinal transmission of a mammalian retrovirus. It also illustrates how the same retrovirus species has transitioned multiple times from an infectious pathogen to a genomic parasite (i.e. retrotransposon), yet experiencing different invasion dynamics in different mammalian hosts. PMID

  14. Cross-Species Transmission and Differential Fate of an Endogenous Retrovirus in Three Mammal Lineages.

    PubMed

    Zhuo, Xiaoyu; Feschotte, Cédric

    2015-01-01

    Endogenous retroviruses (ERVs) arise from retroviruses chromosomally integrated in the host germline. ERVs are common in vertebrate genomes and provide a valuable fossil record of past retroviral infections to investigate the biology and evolution of retroviruses over a deep time scale, including cross-species transmission events. Here we took advantage of a catalog of ERVs we recently produced for the bat Myotis lucifugus to seek evidence for infiltration of these retroviruses in other mammalian species (>100) currently represented in the genome sequence database. We provide multiple lines of evidence for the cross-ordinal transmission of a gammaretrovirus endogenized independently in the lineages of vespertilionid bats, felid cats and pangolin ~13-25 million years ago. Following its initial introduction, the ERV amplified extensively in parallel in both bat and cat lineages, generating hundreds of species-specific insertions throughout evolution. However, despite being derived from the same viral species, phylogenetic and selection analyses suggest that the ERV experienced different amplification dynamics in the two mammalian lineages. In the cat lineage, the ERV appears to have expanded primarily by retrotransposition of a single proviral progenitor that lost infectious capacity shortly after endogenization. In the bat lineage, the ERV followed a more complex path of germline invasion characterized by both retrotransposition and multiple infection events. The results also suggest that some of the bat ERVs have maintained infectious capacity for extended period of time and may be still infectious today. This study provides one of the most rigorously documented cases of cross-ordinal transmission of a mammalian retrovirus. It also illustrates how the same retrovirus species has transitioned multiple times from an infectious pathogen to a genomic parasite (i.e. retrotransposon), yet experiencing different invasion dynamics in different mammalian hosts. PMID

  15. Endogenous Retroviruses in Fish Genomes: From Relics of Past Infections to Evolutionary Innovations?

    PubMed Central

    Naville, Magali; Volff, Jean-Nicolas

    2016-01-01

    The increasing availability of fish genome sequences has allowed to gain new insights into the diversity and host distribution of retroviruses in fish and other vertebrates. This distribution can be assessed through the identification and analysis of endogenous retroviruses, which are proviral remnants of past infections integrated in genomes. Retroviral sequences are probably important for evolution through their ability to induce rearrangements and to contribute regulatory and coding sequences; they may also protect their host against new infections. We argue that the current mass of genome sequences will soon strongly improve our understanding of retrovirus diversity and evolution in aquatic animals, with the identification of new/re-emerging elements and host resistance genes that restrict their infectivity. PMID:27555838

  16. Identification of an ancient endogenous retrovirus, predating the divergence of the placental mammals

    PubMed Central

    Lee, Adam; Nolan, Alison; Watson, Jason; Tristem, Michael

    2013-01-01

    The evolutionary arms race between mammals and retroviruses has long been recognized as one of the oldest host–parasite interactions. Rapid evolution rates in exogenous retroviruses have often made accurate viral age estimations highly problematic. Endogenous retroviruses (ERVs), however, integrate into the germline of their hosts, and are subjected to their evolutionary rates. This study describes, for the first time, a retroviral orthologue predating the divergence of placental mammals, giving it a minimum age of 104–110 Myr. Simultaneously, other orthologous selfish genetic elements (SGEs), inserted into the ERV sequence, provide evidence for the oldest individual mammalian-wide interspersed repeat and medium-reiteration frequency interspersed repeat mammalian repeats, with the same minimum age. The combined use of shared SGEs and reconstruction of viral orthologies defines new limits and increases maximum ‘lookback’ times, with subsequent implications for the field of paleovirology. PMID:23938752

  17. Endogenous Retrovirus Insertion in the KIT Oncogene Determines White and White spotting in Domestic Cats

    PubMed Central

    David, Victor A.; Menotti-Raymond, Marilyn; Wallace, Andrea Coots; Roelke, Melody; Kehler, James; Leighty, Robert; Eizirik, Eduardo; Hannah, Steven S.; Nelson, George; Schäffer, Alejandro A.; Connelly, Catherine J.; O’Brien, Stephen J.; Ryugo, David K.

    2014-01-01

    The Dominant White locus (W) in the domestic cat demonstrates pleiotropic effects exhibiting complete penetrance for absence of coat pigmentation and incomplete penetrance for deafness and iris hypopigmentation. We performed linkage analysis using a pedigree segregating White to identify KIT (Chr. B1) as the feline W locus. Segregation and sequence analysis of the KIT gene in two pedigrees (P1 and P2) revealed the remarkable retrotransposition and evolution of a feline endogenous retrovirus (FERV1) as responsible for two distinct phenotypes of the W locus, Dominant White, and white spotting. A full-length (7125 bp) FERV1 element is associated with white spotting, whereas a FERV1 long terminal repeat (LTR) is associated with all Dominant White individuals. For purposes of statistical analysis, the alternatives of wild-type sequence, FERV1 element, and LTR-only define a triallelic marker. Taking into account pedigree relationships, deafness is genetically linked and associated with this marker; estimated P values for association are in the range of 0.007 to 0.10. The retrotransposition interrupts a DNAase I hypersensitive site in KIT intron 1 that is highly conserved across mammals and was previously demonstrated to regulate temporal and tissue-specific expression of KIT in murine hematopoietic and melanocytic cells. A large-population genetic survey of cats (n = 270), representing 30 cat breeds, supports our findings and demonstrates statistical significance of the FERV1 LTR and full-length element with Dominant White/blue iris (P < 0.0001) and white spotting (P < 0.0001), respectively. PMID:25085922

  18. Endogenous retrovirus insertion in the KIT oncogene determines white and white spotting in domestic cats.

    PubMed

    David, Victor A; Menotti-Raymond, Marilyn; Wallace, Andrea Coots; Roelke, Melody; Kehler, James; Leighty, Robert; Eizirik, Eduardo; Hannah, Steven S; Nelson, George; Schäffer, Alejandro A; Connelly, Catherine J; O'Brien, Stephen J; Ryugo, David K

    2014-10-01

    The Dominant White locus (W) in the domestic cat demonstrates pleiotropic effects exhibiting complete penetrance for absence of coat pigmentation and incomplete penetrance for deafness and iris hypopigmentation. We performed linkage analysis using a pedigree segregating White to identify KIT (Chr. B1) as the feline W locus. Segregation and sequence analysis of the KIT gene in two pedigrees (P1 and P2) revealed the remarkable retrotransposition and evolution of a feline endogenous retrovirus (FERV1) as responsible for two distinct phenotypes of the W locus, Dominant White, and white spotting. A full-length (7125 bp) FERV1 element is associated with white spotting, whereas a FERV1 long terminal repeat (LTR) is associated with all Dominant White individuals. For purposes of statistical analysis, the alternatives of wild-type sequence, FERV1 element, and LTR-only define a triallelic marker. Taking into account pedigree relationships, deafness is genetically linked and associated with this marker; estimated P values for association are in the range of 0.007 to 0.10. The retrotransposition interrupts a DNAase I hypersensitive site in KIT intron 1 that is highly conserved across mammals and was previously demonstrated to regulate temporal and tissue-specific expression of KIT in murine hematopoietic and melanocytic cells. A large-population genetic survey of cats (n = 270), representing 30 cat breeds, supports our findings and demonstrates statistical significance of the FERV1 LTR and full-length element with Dominant White/blue iris (P < 0.0001) and white spotting (P < 0.0001), respectively. PMID:25085922

  19. Endogenous retrovirus induces leukemia in a xenograft mouse model for primary myelofibrosis

    PubMed Central

    Triviai, Ioanna; Ziegler, Marion; Bergholz, Ulla; Oler, Andrew J.; Stübig, Thomas; Prassolov, Vladimir; Fehse, Boris; Kozak, Christine A.; Kröger, Nicolaus; Stocking, Carol

    2014-01-01

    The compound immunodeficiencies in nonobese diabetic (NOD) inbred mice homozygous for the Prkdcscid and Il2rgnull alleles (NSG mice) permit engraftment of a wide-range of primary human cells, enabling sophisticated modeling of human disease. In studies designed to define neoplastic stem cells of primary myelofibrosis (PMF), a myeloproliferative neoplasm characterized by profound disruption of the hematopoietic microenvironment, we observed a high frequency of acute myeloid leukemia (AML) in NSG mice. AML was of mouse origin, confined to PMF-xenografted mice, and contained multiple clonal integrations of ecotropic murine leukemia virus (E-MuLV). Significantly, MuLV replication was not only observed in diseased mice, but also in nontreated NSG controls. Furthermore, in addition to the single ecotropic endogenous retrovirus (eERV) located on chromosome 11 (Emv30) in the NOD genome, multiple de novo germ-line eERV integrations were observed in mice from each of four independent NSG mouse colonies. Analysis confirmed that E-MuLV originated from the Emv30 provirus and that recombination events were not necessary for virus replication or AML induction. Pathogenicity is thus likely attributable to PMF-mediated paracrine stimulation of mouse myeloid cells, which serve as targets for retroviral infection and transformation, as evidenced by integration into the Evi1 locus, a hotspot for retroviral-induced myeloid leukemia. This study thus corroborates a role of paracrine stimulation in PMF disease progression, underlines the importance of target cell type and numbers in MuLV-induced disease, and mandates awareness of replicating MuLV in NOD immunodeficient mice, which can significantly influence experimental results and their interpretation. PMID:24912157

  20. Sequence Variability, Gene Structure, and Expression of Full-Length Human Endogenous Retrovirus H

    PubMed Central

    Jern, Patric; Sperber, Göran O.; Ahlsén, Göran; Blomberg, Jonas

    2005-01-01

    Recently, we identified and classified 926 human endogenous retrovirus H (HERV-H)-like proviruses in the human genome. In this paper, we used the information to, in silico, reconstruct a putative ancestral HERV-H. A calculated consensus sequence was nearly open in all genes. A few manual adjustments resulted in a putative 9-kb HERV-H provirus with open reading frames (ORFs) in gag, pro, pol, and env. Long terminal repeats (LTRs) differed by 1.1%, indicating proximity to an integration event. The gag ORF was extended upstream of the normal myristylation start site. There was a long leader (including a “pre-gag” ORF) region positioned like the N terminus of murine leukemia virus (MLV) “glyco-Gag,” potentially encoding a proline- and serine-rich domain remotely similar to MLV pp12. Another ORF, starting inside the 5′ LTR, had no obvious similarity to known protein domains. Unlike other hitherto described gammaretroviruses, the reconstructed Gag had two zinc finger motifs. Alternative splicing of sequences related to the HERV-H consensus was confirmed using dbEST data. env transcripts were most prevalent in colon tumors, but also in normal testis. We found no evidence for full length env transcripts in the dbEST. HERV-H had a markedly skewed nucleotide composition, disfavoring guanine and favoring cytidine. We conclude that the HERV-H consensus shared a gene arrangement common to gammaretroviruses with gag separated by stop codon from pro-pol in the same reading frame, while env resides in another reading frame. There was also alternative splicing. HERV-H consensus yielded new insights in gammaretroviral evolution and will be useful as a model in studies on expression and function. PMID:15858016

  1. Endogenous retrovirus and radiation-induced leukemia in the RMF mouse

    SciTech Connect

    Tennant, R.W.; Boone, L.R.; Lalley, P.; Yang, W.K.

    1982-01-01

    The induction of myeloid leukemia in irradiated RFM/Un mice has been associated with retrovirus infection. However, two characteristics of this strain complicate efforts to define the role of the virus. This strain possesses only one inducible host range class of endogenous virus and a unique gene, in addition to the Fv-1/sup n/ locus, which specifically restricts exogenous infection by endogenous viruses. These characteristics possibly account for absence of recombinant viruses in this strain, even though virus is amply expressed during most of the animal's life span. We have examined further the distribution of retrovirus sequences and the chromosomal locus of the inducible virus in this strain. This report describes evidence for additional viral sequences in cells of a radiation-induced myeloid leukemia line and discusses the possible origin of these added copies.

  2. Retroviruses.

    ERIC Educational Resources Information Center

    Varmus, Harold

    1988-01-01

    Discusses the growth, development, and unusual parasitic nature of the retrovirus community. Reviews these infectious cancer-causing agents as models for the study of fundamental biological problems, tools for genetic manipulations, and problems posed by their pathogenic potential in humans and animal hosts where they cause diseases such as…

  3. Proliferation of Endogenous Retroviruses in the Early Stages of a Host Germ Line Invasion

    PubMed Central

    Ishida, Yasuko; Zhao, Kai; Greenwood, Alex D.; Roca, Alfred L.

    2015-01-01

    Endogenous retroviruses (ERVs) comprise 8% of the human genome and are common in all vertebrate genomes. The only retrovirus known to be currently transitioning from exogenous to endogenous form is the koala retrovirus (KoRV), making koalas (Phascolarctos cinereus) ideal for examining the early stages of retroviral endogenization. To distinguish endogenous from exogenous KoRV proviruses, we isolated koala genomic regions flanking KoRV integration sites. In three wild southern Australian koalas, there were fewer KoRV loci than in three captive Queensland koalas, consistent with reports that southern Australian koalas carry fewer KoRVs. Of 39 distinct KoRV proviral loci examined in a sire–dam–progeny triad, all proved to be vertically transmitted and endogenous; none was exogenous. Of the 39 endogenous KoRVs (enKoRVs), only one was present in the genomes of both the sire and the dam, suggesting that, at this early stage in the retroviral invasion of a host germ line, very large numbers of ERVs have proliferated at very low frequencies in the koala population. Sequence divergence between the 5′- and 3′-long terminal repeats (LTRs) of a provirus can be used as a molecular clock. Within each of ten enKoRVs, the 5′-LTR sequence was identical to the 3′-LTR sequence, suggesting a maximum age for enKoRV invasion of the koala germ line of approximately 22,200–49,900 years ago, although a much younger age is possible. Across the ten proviruses, seven LTR haplotypes were detected, indicating that at least seven different retroviral sequences had entered the koala germ line. PMID:25261407

  4. Proliferation of endogenous retroviruses in the early stages of a host germ line invasion.

    PubMed

    Ishida, Yasuko; Zhao, Kai; Greenwood, Alex D; Roca, Alfred L

    2015-01-01

    Endogenous retroviruses (ERVs) comprise 8% of the human genome and are common in all vertebrate genomes. The only retrovirus known to be currently transitioning from exogenous to endogenous form is the koala retrovirus (KoRV), making koalas (Phascolarctos cinereus) ideal for examining the early stages of retroviral endogenization. To distinguish endogenous from exogenous KoRV proviruses, we isolated koala genomic regions flanking KoRV integration sites. In three wild southern Australian koalas, there were fewer KoRV loci than in three captive Queensland koalas, consistent with reports that southern Australian koalas carry fewer KoRVs. Of 39 distinct KoRV proviral loci examined in a sire-dam-progeny triad, all proved to be vertically transmitted and endogenous; none was exogenous. Of the 39 endogenous KoRVs (enKoRVs), only one was present in the genomes of both the sire and the dam, suggesting that, at this early stage in the retroviral invasion of a host germ line, very large numbers of ERVs have proliferated at very low frequencies in the koala population. Sequence divergence between the 5'- and 3'-long terminal repeats (LTRs) of a provirus can be used as a molecular clock. Within each of ten enKoRVs, the 5'-LTR sequence was identical to the 3'-LTR sequence, suggesting a maximum age for enKoRV invasion of the koala germ line of approximately 22,200-49,900 years ago, although a much younger age is possible. Across the ten proviruses, seven LTR haplotypes were detected, indicating that at least seven different retroviral sequences had entered the koala germ line. PMID:25261407

  5. Drosophila germline invasion by the endogenous retrovirus gypsy: involvement of the viral env gene.

    PubMed

    Pelisson, A; Mejlumian, L; Robert, V; Terzian, C; Bucheton, A

    2002-10-01

    The endogenous retrovirus gypsy is expressed at high levels in mutant flamenco female flies. Gypsy viral particles extracted from such flies can infect naive flamenco individuals raised in the presence of these extracts mixed into their food. This results in the integration of new proviruses into the germline genome. These proviruses can then increase their copy number by (1) expression in the flamenco female somatic cells, (2) transfer into the oocyte and (3) integration into the genome of the progeny. Surprisingly, unlike the infection observed in the feeding experiments, this strategy of endogenous proviral multiplication does not seem to involve the expression of the viral env gene. PMID:12225916

  6. Pluripotency and the endogenous retrovirus HERVH: Conflict or serendipity?

    PubMed

    Izsvák, Zsuzsanna; Wang, Jichang; Singh, Manvendra; Mager, Dixie L; Hurst, Laurence D

    2016-01-01

    Remnants of ancient retroviral infections during evolution litter all mammalian genomes. In modern humans, such endogenous retroviral (ERV) sequences comprise at least 8% of the genome. While ERVs and other types of transposable elements undoubtedly contribute to the genomic "junk yard", functions for some ERV sequences have been demonstrated, with growing evidence that ERVs can be important players in gene regulatory processes. Here we focus on one particular large family of human ERVs, termed HERVH, which several recent studies suggest has a key regulatory role in human pluripotent stem cells. Remarkably, this is not the first instance of an ERV controlling pluripotency. We speculate as to why this convergent evolution might have come about, suggesting that it may reflect selection on the virus to extend the time available for transposition. Alternatively it may reflect serendipity alone. PMID:26735931

  7. An Evolutionarily Young Polar Bear (Ursus maritimus) Endogenous Retrovirus Identified from Next Generation Sequence Data

    PubMed Central

    Tsangaras, Kyriakos; Mayer, Jens; Alquezar-Planas, David E.; Greenwood, Alex D.

    2015-01-01

    Transcriptome analysis of polar bear (Ursus maritimus) tissues identified sequences with similarity to Porcine Endogenous Retroviruses (PERV). Based on these sequences, four proviral copies and 15 solo long terminal repeats (LTRs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. Closely related sequences were identified by PCR analysis of brown bear (Ursus arctos) and black bear (Ursus americanus) but were absent in non-Ursinae bear species. The virus was therefore designated UrsusERV. Two distinct groups of LTRs were observed including a recombinant ERV that contained one LTR belonging to each group indicating that genomic invasions by at least two UrsusERV variants have recently occurred. Age estimates based on proviral LTR divergence and conservation of integration sites among ursids suggest the viral group is only a few million years old. The youngest provirus was polar bear specific, had intact open reading frames (ORFs) and could potentially encode functional proteins. Phylogenetic analyses of UrsusERV consensus protein sequences suggest that it is part of a pig, gibbon and koala retrovirus clade. The young age estimates and lineage specificity of the virus suggests UrsusERV is a recent cross species transmission from an unknown reservoir and places the viral group among the youngest of ERVs identified in mammals. PMID:26610552

  8. Wolbachia Influences the Maternal Transmission of the gypsy Endogenous Retrovirus in Drosophila melanogaster

    PubMed Central

    Touret, Franck; Guiguen, François

    2014-01-01

    ABSTRACT The endosymbiotic bacteria of the genus Wolbachia are present in most insects and are maternally transmitted through the germline. Moreover, these intracellular bacteria exert antiviral activity against insect RNA viruses, as in Drosophila melanogaster, which could explain the prevalence of Wolbachia bacteria in natural populations. Wolbachia is maternally transmitted in D. melanogaster through a mechanism that involves distribution at the posterior pole of mature oocytes and then incorporation into the pole cells of the embryos. In parallel, maternal transmission of several endogenous retroviruses is well documented in D. melanogaster. Notably, gypsy retrovirus is expressed in permissive follicle cells and transferred to the oocyte and then to the offspring by integrating into their genomes. Here, we show that the presence of Wolbachia wMel reduces the rate of gypsy insertion into the ovo gene. However, the presence of Wolbachia does not modify the expression levels of gypsy RNA and envelope glycoprotein from either permissive or restrictive ovaries. Moreover, Wolbachia affects the pattern of distribution of the retroviral particles and the gypsy envelope protein in permissive follicle cells. Altogether, our results enlarge the knowledge of the antiviral activity of Wolbachia to include reducing the maternal transmission of endogenous retroviruses in D. melanogaster. PMID:25182324

  9. An Evolutionarily Young Polar Bear (Ursus maritimus) Endogenous Retrovirus Identified from Next Generation Sequence Data.

    PubMed

    Tsangaras, Kyriakos; Mayer, Jens; Alquezar-Planas, David E; Greenwood, Alex D

    2015-11-01

    Transcriptome analysis of polar bear (Ursus maritimus) tissues identified sequences with similarity to Porcine Endogenous Retroviruses (PERV). Based on these sequences, four proviral copies and 15 solo long terminal repeats (LTRs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. Closely related sequences were identified by PCR analysis of brown bear (Ursus arctos) and black bear (Ursus americanus) but were absent in non-Ursinae bear species. The virus was therefore designated UrsusERV. Two distinct groups of LTRs were observed including a recombinant ERV that contained one LTR belonging to each group indicating that genomic invasions by at least two UrsusERV variants have recently occurred. Age estimates based on proviral LTR divergence and conservation of integration sites among ursids suggest the viral group is only a few million years old. The youngest provirus was polar bear specific, had intact open reading frames (ORFs) and could potentially encode functional proteins. Phylogenetic analyses of UrsusERV consensus protein sequences suggest that it is part of a pig, gibbon and koala retrovirus clade. The young age estimates and lineage specificity of the virus suggests UrsusERV is a recent cross species transmission from an unknown reservoir and places the viral group among the youngest of ERVs identified in mammals. PMID:26610552

  10. Viral and cellular requirements for the budding of Feline Endogenous Retrovirus RD-114

    PubMed Central

    2011-01-01

    Background RD-114 virus is a feline endogenous retrovirus and produced as infectious viruses in some feline cell lines. Recently, we reported the contamination of an infectious RD-114 virus in a proportion of live attenuated vaccines for dogs and cats. It is very difficult to completely knock out the RD-114 proviruses from cells, as endogenous retroviruses are usually integrated multiply into the host genome. However, it may be possible to reduce the risk of contamination of RD-114 virus by regulating the viral release from cells. Results In this study, to understand the molecular mechanism of RD-114 virus budding, we attempted to identify the viral and cellular requirements for RD-114 virus budding. Analyses of RD-114 L-domain mutants showed that the PPPY sequence in the pp15 region of Gag plays a critical role in RD-114 virus release as viral L-domain. Furthermore, we investigated the cellular factors required for RD-114 virus budding. We demonstrated that RD-114 virus release was inhibited by overexpression of dominant negative mutants of Vps4A, Vps4B, and WWP2. Conclusions These results strongly suggest that RD-114 budding utilizes the cellular multivesicular body sorting pathway similar to many other retroviruses. PMID:22168342

  11. Detection and characterization of endogenous retroviruses in the horse genome by in silico analysis.

    PubMed

    Garcia-Etxebarria, Koldo; Jugo, Begoña M

    2012-12-01

    Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses that have become incorporated into the host genome. Little is known about ERVs in the horse genome. By combining 3 bioinformatic approaches, we detected 1947 putative ERVs in the horse genome. These equine ERVs are not scattered randomly across the genome and are especially abundant in the X chromosome. Based on phylogenetic relationships, some of these equine ERVs were classified into 15 previously uncharacterized families of Classes I, II and III. Compared with the cow and other species, the horse genome appears to container fewer ERVs. Although this could be due to limitations of the detection process, it could also stem from characteristics of the horse genome or the effect of the domestication process. PMID:23026066

  12. Human Endogenous Retroviruses as Pathogenic Factors in the Development of Schizophrenia

    PubMed Central

    Slokar, Gorjan; Hasler, Gregor

    2016-01-01

    Schizophrenia is a complex disorder, characterized by the interplay between genetic and environmental factors. Human endogenous retroviruses (HERVs), genetic elements that originated from infections by exogenous retroviruses millions of years ago, comprise ~8% of the human genome. Here, we provide a comprehensive review of accumulating evidence, detailing HERV aberrancies associated with schizophrenia. Studies examining the genome, transcriptome, and proteome of individuals with schizophrenia provide data that support the association of these viral elements with the disorder. Molecular differences can be found within the central nervous system and peripheral tissues. However, additional studies are needed to substantiate the reported link and to address several discrepancies among previous investigations. We further discuss potentially relevant pathogenic mechanisms to the development of schizophrenia. PMID:26793126

  13. The Population History of Endogenous Retroviruses in Mule Deer (Odocoileus hemionus)

    PubMed Central

    2014-01-01

    Mobile elements are powerful agents of genomic evolution and can be exceptionally informative markers for investigating species and population-level evolutionary history. While several studies have utilized retrotransposon-based insertional polymorphisms to resolve phylogenies, few population studies exist outside of humans. Endogenous retroviruses are LTR-retrotransposons derived from retroviruses that have become stably integrated in the host genome during past infections and transmitted vertically to subsequent generations. They offer valuable insight into host-virus co-evolution and a unique perspective on host evolutionary history because they integrate into the genome at a discrete point in time. We examined the evolutionary history of a cervid endogenous gammaretrovirus (CrERVγ) in mule deer (Odocoileus hemionus). We sequenced 14 CrERV proviruses (CrERV-in1 to -in14), and examined the prevalence and distribution of 13 proviruses in 262 deer among 15 populations from Montana, Wyoming, and Utah. CrERV absence in white-tailed deer (O. virginianus), identical 5′ and 3′ long terminal repeat (LTR) sequences, insertional polymorphism, and CrERV divergence time estimates indicated that most endogenization events occurred within the last 200000 years. Population structure inferred from CrERVs (F ST = 0.008) and microsatellites (θ = 0.01) was low, but significant, with Utah, northwestern Montana, and a Helena herd being particularly differentiated. Clustering analyses indicated regional structuring, and non-contiguous clustering could often be explained by known translocations. Cluster ensemble results indicated spatial localization of viruses, specifically in deer from northeastern and western Montana. This study demonstrates the utility of endogenous retroviruses to elucidate and provide novel insight into both ERV evolutionary history and the history of contemporary host populations. PMID:24336966

  14. The population history of endogenous retroviruses in mule deer (Odocoileus heminous)

    USGS Publications Warehouse

    Kamath, Pauline L.; Elleder, Daniel; Bao, Le; Cross, Paul C.; Powell, John H.; Poss, Mary

    2013-01-01

    Mobile elements are powerful agents of genomic evolution and can be exceptionally informative markers for investigating species and population-level evolutionary history. While several studies have utilized retrotransposon-based insertional polymorphisms to resolve phylogenies, few population studies exist outside of humans. Endogenous retroviruses are LTR-retrotransposons derived from retroviruses that have become stably integrated in the host genome during past infections and transmitted vertically to subsequent generations. They offer valuable insight into host-virus co-evolution and a unique perspective on host evolutionary history because they integrate into the genome at a discrete point in time. We examined the evolutionary history of a cervid endogenous gammaretrovirus (CrERVγ) in mule deer (Odocoileus hemionus). We sequenced 14 CrERV proviruses (CrERV-in1 to -in14), and examined the prevalence and distribution of 13 proviruses in 262 deer among 15 populations from Montana, Wyoming, and Utah. CrERV absence in white-tailed deer (O. virginianus), identical 5′ and 3′ long terminal repeat (LTR) sequences, insertional polymorphism, and CrERV divergence time estimates indicated that most endogenization events occurred within the last 200000 years. Population structure inferred from CrERVs (F ST = 0.008) and microsatellites (θ = 0.01) was low, but significant, with Utah, northwestern Montana, and a Helena herd being particularly differentiated. Clustering analyses indicated regional structuring, and non-contiguous clustering could often be explained by known translocations. Cluster ensemble results indicated spatial localization of viruses, specifically in deer from northeastern and western Montana. This study demonstrates the utility of endogenous retroviruses to elucidate and provide novel insight into both ERV evolutionary history and the history of contemporary host populations.

  15. Multiple Sclerosis between Genetics and Infections: Human Endogenous Retroviruses in Monocytes and Macrophages

    PubMed Central

    Morandi, Elena; Tarlinton, Rachael E.; Gran, Bruno

    2015-01-01

    The etiology of multiple sclerosis (MS) is still unknown, but there is strong evidence that genetic predisposition associated with environmental factors can trigger the disease. An estimated 30 million years ago, exogenous retroviruses are thought to have integrated themselves into human germ line cells, becoming part of human DNA and being transmitted over generations. Usually such human endogenous retroviruses (HERVs) are silenced or expressed at low levels, but in some pathological conditions, such as MS, their expression is higher than that in the healthy population. Three HERV families have been associated with MS: HERV-H, HERV-K, and HERV-W. The envelope protein of MS-associated retrovirus (MSRV) from the HERV-W family currently has the strongest evidence as a potential trigger for MS. In addition to expression in peripheral immune cells, MSRV is expressed in monocytes and microglia in central nervous system lesions of people with MS and, through the activation of toll-like receptor 4, it has been shown to drive the production of proinflammatory cytokines, reduction of myelin protein expression, and death of oligodendrocyte precursors. In conclusion, the association between HERVs and MS is well documented and a pathological role for MSRV in MS is plausible. Further studies are required to determine whether the presence of these HERVs is a cause or an effect of immune dysregulation in MS. PMID:26734011

  16. Implication of human endogenous retroviruses in the development of autoimmune diseases.

    PubMed

    Balada, Eva; Vilardell-Tarrés, Miquel; Ordi-Ros, Josep

    2010-08-01

    Retroviruses can exist in an endogenous form, in which viral sequences are integrated into the human germ line and are vertically transmitted in a Mendelian fashion. Human endogenous retroviruses (HERVs), probably representing footprints of ancient germ-cell retroviral infections, occupy about 1% of the human genome. Some HERVs emerged in the genome over 25 million years ago, while others have appeared rather recently, at about the time of hominid and ape lineages divergence. Although some of these elements show mutations and deletions, some HERVs are transcriptionally active and produce functional proteins. Some medical conditions, such as cancer and autoimmune diseases, are linked to the transcription of some of the HERVs genes, to the expression of HERVs proteins (that may act as superantigens, for example), and/or to the development of antibodies against them that might cross-react with our own proteins. Their genetic sequences may also be, totally or partially, integrated into genes that regulate the immune response. These mechanisms could give rise to autoimmune diseases, such as lupus erythematosus, insulin-dependent diabetes mellitus, multiple sclerosis, Sjögren's syndrome, and rheumatoid arthritis, among others. This review is aimed at discussing evidence for a possible role of HERVs in the etiopathogenesis of different autoimmune diseases. PMID:20635879

  17. T-cell-receptor dose and the time of treatment during murine retrovirus infection for maintenance of immune function.

    PubMed Central

    Liang, B; Ardestani, S; Marchalonis, J J; Watson, R R

    1996-01-01

    C57BL/6 mice were injected with different doses of human T-cell receptor (TCR) V beta 8.1 CDR1 peptide at different times after murine retrovirus (LP-BM5) infection. Injection with TCR V beta 8.1 CDR1 peptide largely prevented the retrovirus-induced reduction in B- and T-cell proliferation, and T-helper 1 (Th1) cytokines [interleukin-2 (IL-2) and interferon-gamma (IFN-gamma)] secretion. It also suppressed T-helper 2 (Th2) cytokines (IL-6 and IL-10) production, which was stimulated by retrovirus infection. These effects were accomplished using at least 100 micrograms of peptide per mouse and the most effective dose of peptide had to be given within 4 weeks after retrovirus infection. Immunization with doses above 100 micrograms/mouse as long as 4 weeks postinfection maintained natural killer (NK) cell activity during retrovirus infection. Reducing the dose of peptide or delaying it until the disease progressed towards early murine acquired immune deficiency syndrome (AIDS) allowed development of immune dysfunction. These studies provide data suggesting that immune dysfunction, induced by murine retrovirus infection, was largely prevented by TCR V beta CDR1 peptide injection. PMID:8698380

  18. Splicing of a human endogenous retrovirus to a novel phospholipase A2 related gene.

    PubMed Central

    Feuchter-Murthy, A E; Freeman, J D; Mager, D L

    1993-01-01

    As part of an investigation into the effects of endogenous retroviruses on adjacent genes, we have isolated a cDNA clone derived from the human teratocarcinoma cell line NTera2D1 representing a chimeric transcript in which an endogenous retrovirus-like element, RTVL-H, has been spliced to downstream cellular sequences. The 5' terminus of this clone, termed AF-5, occurs one bp downstream of the predicted transcriptional start site in the RTVL-H long terminal repeat (LTR). AF-5 contains an open reading frame of 689 amino acids beginning within RTVL-H sequences that has two domains of homology with phospholipase A2 (PLA2). These domains, of approximately 120 amino acids each, are 30-38% identical to secreted PLA2s and contain sequence features of both group I and II enzymes. The corresponding AF-5 transcript is 2.5 kb and is derived from a single copy novel gene termed PLA2L. Southern analysis indicates that the RTVL-H element is normally present in human DNA upstream of the PLA2L gene. RTVL-H/PLA2L chimeric transcripts were detected in two independent teratocarcinoma cell lines but not in several other cell lines or primary human tissues. Characterization of additional cDNA clones and PCR analysis indicates that multiple RTVL-H/PLA2L alternatively spliced transcripts are expressed. No evidence has been found for transcription from a non-LTR promoter. These findings strongly suggest that the endogenous LTR promotes expression of the human PLA2L gene in teratocarcinoma cells. Images PMID:8382789

  19. Genome-wide detection and characterization of endogenous retroviruses in Bos taurus.

    PubMed

    Garcia-Etxebarria, Koldo; Jugo, Begoña Marina

    2010-10-01

    Endogenous retroviruses (ERVs) are the proviral phase of exogenous retroviruses that become integrated into a host germ line. They can play an important role in the host genome. Bioinformatic tools have been used to detect ERVs in several vertebrates, primarily primates and rodents. Less information is available regarding ERVs in other mammalian groups, and the source of this information is basically experimental. We analyzed the genome of the cow (Bos taurus) using three different methods. A BLAST-based method detected 928 possible ERVs, LTR_STRUC detected 4,487 elements flanked by long terminal repeats (LTRs), and Retrotector detected 9,698 ERVs. The ERVs were not homogeneously distributed across chromosomes; the number of ERVs was positively correlated with chromosomal size and negatively correlated with chromosomal GC content. The bovine ERVs (BoERVs) were classified into 24 putative families, with 20 of them not previously described. One of these new families, BoERV1, was the most abundant family and appeared to be specific to ruminants. An analysis of representatives of ERV families from rodents, primates, and ruminants showed a phylogenetic relationship following their hosts' relationships. This study demonstrates the importance of using multiple methods when trying to identify new ERVs and shows that the number of bovine ERV families is not as limited as previously thought. PMID:20686017

  20. The histone methyltransferase SETDB1 represses endogenous and exogenous retroviruses in B lymphocytes

    PubMed Central

    Collins, Patrick L.; Kyle, Katherine E.; Egawa, Takeshi; Shinkai, Yoichi; Oltz, Eugene M.

    2015-01-01

    Genome stability relies on epigenetic mechanisms that enforce repression of endogenous retroviruses (ERVs). Current evidence suggests that distinct chromatin-based mechanisms repress ERVs in cells of embryonic origin (histone methylation dominant) vs. more differentiated cells (DNA methylation dominant). However, the latter aspect of this model has not been tested. Remarkably, and in contrast to the prevailing model, we find that repressive histone methylation catalyzed by the enzyme SETDB1 is critical for suppression of specific ERV families and exogenous retroviruses in committed B-lineage cells from adult mice. The profile of ERV activation in SETDB1-deficient B cells is distinct from that observed in corresponding embryonic tissues, despite the loss of repressive chromatin modifications at all ERVs. We provide evidence that, on loss of SETDB1, ERVs are activated in a lineage-specific manner depending on the set of transcription factors available to target proviral regulatory elements. These findings have important implications for genome stability in somatic cells, as well as the interface between epigenetic repression and viral latency. PMID:26100872

  1. Detection and Characterization of Porcine Endogenous Retrovirus in Porcine Plasma and Porcine Factor VIII

    PubMed Central

    Takefman, Daniel M.; Wong, Susan; Maudru, Thomas; Peden, Keith; Wilson, Carolyn A.

    2001-01-01

    The pig genome contains porcine endogenous retroviruses (PERVs) capable of infecting human cells. Detection of infectious retrovirus in porcine peripheral blood mononuclear cells and endothelial cells suggested to us that pig plasma is likely to contain PERV. Both PERV env sequences and viral reverse transcriptase (RT) activity were detected in all plasma samples isolated from four NIH minipigs. To detect infectious virus from plasma, we performed a culture assay using three cell lines of feline, swine, and human origin that had previously been shown to be permissive for PERV. Infectious virus was successfully cultured from all four NIH minipig plasmas on the swine cell line ST-IOWA. Using RT-PCR with env-specific primers, we could detect expression of PERV class C envelope in the supernatant of ST-IOWA cells that had been exposed to each pig plasma. We next examined a pig plasma derivative, Hyate:C (porcine factor VIII), and found evidence of PERV particles, since all six lots examined were positive for PERV RNA and RT activity. However, infectious virus could not be detected in clinical lots of Hyate:C, suggesting that the manufacturing process might reduce the load of infectious virus to levels below detectable limits of the assay. Detection of infectious virus in porcine plasma confirms and extends the previous findings that certain porcine cells express PERV when manipulated in vitro and clearly demonstrates that there are porcine cells that express infectious PERV constitutively in vivo. PMID:11312325

  2. Regulatory evolution of innate immunity through co-option of endogenous retroviruses

    PubMed Central

    Chuong, Edward B.; Elde, Nels C.; Feschotte, Cédric

    2016-01-01

    Endogenous retroviruses (ERVs) are abundant in mammalian genomes and contain sequences modulating transcription. How ERV propagation impacts the evolution of gene regulation remains poorly understood. Here we show that ERVs have shaped the evolution of a transcriptional network underlying the interferon (IFN) response, a major branch of innate immunity. We found that lineage-specific ERVs have dispersed numerous IFN-inducible enhancers independently in diverse mammalian genomes. CRISPR-Cas9 deletion of a subset of these ERV elements in the human genome impaired expression of adjacent IFN-induced genes and revealed their involvement in the regulation of essential immune functions, including activation of the AIM2 inflammasome. While these regulatory sequences likely arose in ancient viruses, they now constitute a dynamic reservoir of IFN-inducible enhancers fueling genetic innovation in mammalian immune defenses. PMID:26941318

  3. Transcriptional activity of human endogenous retrovirus in Albanian children with autism spectrum disorders.

    PubMed

    Balestrieri, Emanuela; Cipriani, Chiara; Matteucci, Claudia; Capodicasa, Natale; Pilika, Anita; Korca, Ina; Sorrentino, Roberta; Argaw-Denboba, Ayele; Bucci, Ilaria; Miele, Martino Tony; Coniglio, Antonella; Alessandrelli, Riccardo; Sinibaldi Vallebona, Paola

    2016-09-01

    Recent studies suggest that autism spectrum disorders (ASD) result from interactions between genetic and environmental factors, whose possible links could be represented by epigenetic mechanisms. Here, we investigated the transcriptional activity of three human endogenous retrovirus (HERV) families, in peripheral blood mononuclear cells (PBMCs) from Albanian ASD children, by quantitative real-time PCR. We aimed to confirm the different expression profile already found in Italian ASD children, and to highlight any social and family health condition emerging from information gathered through a questionnaire, to be included among environmental risk factors. The presence of increased HERV-H transcriptional activity in all autistic patients could be understood as a constant epigenetic imprinting of the disease, potentially useful for early diagnosis and for the development of effective novel therapeutic strategies. PMID:27602423

  4. Inhibiting DNA methylation causes an interferon response in cancer via dsRNA including endogenous retroviruses

    PubMed Central

    Chiappinelli, Katherine B.; Strissel, Pamela L.; Desrichard, Alexis; Li, Huili; Henke, Christine; Akman, Benjamin; Hein, Alexander; Rote, Neal S.; Cope, Leslie M.; Snyder, Alexandra; Makarov, Vladimir; Buhu, Sadna; Slamon, Dennis J.; Wolchok, Jedd D.; Pardoll, Drew M.; Beckmann, Matthias W.; Zahnow, Cynthia A.; Mergoub, Taha; Chan, Timothy A.; Baylin, Stephen B.; Strick, Reiner

    2015-01-01

    Summary We show that DNA methyltransferase inhibitors (DNMTis) upregulate immune signaling in cancer through the viral defense pathway. In ovarian cancer (OC), DNMTis trigger cytosolic sensing of double-stranded RNA (dsRNA) causing a Type I Interferon response and apoptosis. Knocking down dsRNA sensors TLR3 and MAVS reduces this response twofold, and blocking interferon beta or its receptor abrogates it. Upregulation of hypermethylated endogenous retrovirus (ERV) genes accompanies the response and ERV overexpression activates the response. Basal levels of ERV and viral defense gene expression significantly correlate in primary OC and the latter signature separates primary samples for multiple tumor types from The Cancer Genome Atlas into low versus high expression groups. In melanoma patients treated with an immune checkpoint therapy, high viral defense signature expression in tumors significantly associates with durable clinical response and DNMTi treatment sensitizes to anti-CTLA4 therapy in a pre-clinical melanoma model. PMID:26317466

  5. Regulatory evolution of innate immunity through co-option of endogenous retroviruses.

    PubMed

    Chuong, Edward B; Elde, Nels C; Feschotte, Cédric

    2016-03-01

    Endogenous retroviruses (ERVs) are abundant in mammalian genomes and contain sequences modulating transcription. The impact of ERV propagation on the evolution of gene regulation remains poorly understood. We found that ERVs have shaped the evolution of a transcriptional network underlying the interferon (IFN) response, a major branch of innate immunity, and that lineage-specific ERVs have dispersed numerous IFN-inducible enhancers independently in diverse mammalian genomes. CRISPR-Cas9 deletion of a subset of these ERV elements in the human genome impaired expression of adjacent IFN-induced genes and revealed their involvement in the regulation of essential immune functions, including activation of the AIM2 inflammasome. Although these regulatory sequences likely arose in ancient viruses, they now constitute a dynamic reservoir of IFN-inducible enhancers fueling genetic innovation in mammalian immune defenses. PMID:26941318

  6. Distribution of endogenous type B and type D sheep retrovirus sequences in ungulates and other mammals.

    PubMed Central

    Hecht, S J; Stedman, K E; Carlson, J O; DeMartini, J C

    1996-01-01

    The jaagsiekte sheep retrovirus (JSRV), which appears to be a type B/D retrovirus chimera, has been incriminated as the cause of ovine pulmonary carcinoma. Recent studies suggest that the sequences related to this virus are found in the genomes of normal sheep and goats. To learn whether there are breeds of sheep that lack the endogenous viral sequences and to study their distribution among other groups of mammals, we surveyed several domestic sheep and goat breeds, other ungulates, and various mammal groups for sequences related to JSRV. Probes prepared from the envelope (SU) region of JSRV and the capsid (CA) region of a Peruvian type D virus related to JSRV were used in Southern blot hybridization with genomic DNA followed by low- and high-stringency washes. Fifteen to 20 CA and SU bands were found in all members of the 13 breeds of domestic sheep and 6 breeds of goats tested. There were similar findings in 6 wild Ovis and Capra genera. Within 22 other genera of Bovidae including domestic cattle, and 7 other families of Artiodactyla including Cervidae, there were usually a few CA or SU bands at low stringency and rare bands at high stringency. Among 16 phylogenetically distant genera, there were generally fewer bands hybridizing with either probe. These results reveal wide-spread phylogenetic distribution of endogenous type B and type D retroviral sequences related to JSRV among mammals and argue for further investigation of their potential role in disease. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8622932

  7. The aliens inside human DNA: HERV-W/MSRV/syncytin-1 endogenous retroviruses and neurodegeneration.

    PubMed

    Dolei, Antonina; Uleri, Elena; Ibba, Gabriele; Caocci, Maurizio; Piu, Claudia; Serra, Caterina

    2015-06-01

    The human genome contains remnants of ancestral retroviruses now endogenously transmitted, called human endogenous retroviruses (HERVs). HERVs can be variably expressed, and both beneficial and detrimental effects have described. This review focuses on the MSRV and syncytin-1 HERV-W elements in relationship to neurodegeneration in view of their neuro-pathogenic and immune-pathogenic properties. Multiple sclerosis (MS) and a neurodegenerative disease (neuroAIDS) are reported in this review. In vivo studies in patients and controls for molecular epidemiology and follow-up studies are reviewed, along with in vitro cellular studies of the effects of treatments and of molecular mechanisms. HERV-W/MSRV has been repeatedly found in MS patients (in blood, spinal fluid, and brain samples), and MRSV presence/load strikingly parallels MS stages and active/remission phases, as well as therapy outcome. The DNA of MS patients has increased MSRVenv copies, while syncytin-1 copies are unchanged in controls. Presence of MSRV in the spinal fluid predicted the worst MS progression, ten years in advance. The Epstein-Barr virus (EBV) activates HERV-W/MSRV both in vitro and in vivo. With respect to neuroAIDS, the HIV transactivator of transcription (Tat) protein activates HERV-W/MSRV in monocytes/macrophages and astrocytes indirectly by interaction with TLR4 and induction of TNFa. HERV-W/MSRV can be considered a biomarker for MS behavior and therapy outcome. Regarding MS pathogenesis, we postulate the possibility for EBV of an initial trigger of future MS, years later, and for MSRV of a direct role of effector of neuropathogenesis during MS. Additionally, HERV-W/MSR/syncytin-1 activation by HIV Tat could contribute to the HIV-related neurodegeneration. PMID:26142666

  8. Utility of next-generation RNA-sequencing in identifying chimeric transcription involving human endogenous retroviruses.

    PubMed

    Sokol, Martin; Jessen, Karen Margrethe; Pedersen, Finn Skou

    2016-01-01

    Several studies have shown that human endogenous retroviruses and endogenous retrovirus-like repeats (here collectively HERVs) impose direct regulation on human genes through enhancer and promoter motifs present in their long terminal repeats (LTRs). Although chimeric transcription in which novel gene isoforms containing retroviral and human sequence are transcribed from viral promoters are commonly associated with disease, regulation by HERVs is beneficial in other settings; for example, in human testis chimeric isoforms of TP63 induced by an ERV9 LTR protect the male germ line upon DNA damage by inducing apoptosis, whereas in the human globin locus the γ- and β-globin switch during normal hematopoiesis is mediated by complex interactions of an ERV9 LTR and surrounding human sequence. The advent of deep sequencing or next-generation sequencing (NGS) has revolutionized the way researchers solve important scientific questions and develop novel hypotheses in relation to human genome regulation. We recently applied next-generation paired-end RNA-sequencing (RNA-seq) together with chromatin immunoprecipitation with sequencing (ChIP-seq) to examine ERV9 chimeric transcription in human reference cell lines from Encyclopedia of DNA Elements (ENCODE). This led to the discovery of advanced regulation mechanisms by ERV9s and other HERVs across numerous human loci including transcription of large gene-unannotated genomic regions, as well as cooperative regulation by multiple HERVs and non-LTR repeats such as Alu elements. In this article, well-established examples of human gene regulation by HERVs are reviewed followed by a description of paired-end RNA-seq, and its application in identifying chimeric transcription genome-widely. Based on integrative analyses of RNA-seq and ChIP-seq, data we then present novel examples of regulation by ERV9s of tumor suppressor genes CADM2 and SEMA3A, as well as transcription of an unannotated region. Taken together, this article highlights

  9. Infectious Entry Pathway Mediated by the Human Endogenous Retrovirus K Envelope Protein

    PubMed Central

    Robinson, Lindsey R.

    2016-01-01

    ABSTRACT Endogenous retroviruses (ERVs), the majority of which exist as degraded remnants of ancient viruses, comprise approximately 8% of the human genome. The youngest human ERVs (HERVs) belong to the HERV-K(HML-2) subgroup and were endogenized within the past 1 million years. The viral envelope protein (ENV) facilitates the earliest events of endogenization (cellular attachment and entry), and here, we characterize the requirements for HERV-K ENV to mediate infectious cell entry. Cell-cell fusion assays indicate that a minimum of two events are required for fusion, proteolytic processing by furin-like proteases and exposure to acidic pH. We generated an infectious autonomously replicating recombinant vesicular stomatitis virus (VSV) in which the glycoprotein was replaced by HERV-K ENV. HERV-K ENV imparts an endocytic entry pathway that requires dynamin-mediated membrane scission and endosomal acidification but is distinct from clathrin-dependent or macropinocytic uptake pathways. The lack of impediments to the replication of the VSV core in eukaryotic cells allowed us to broadly survey the HERV-K ENV-dictated tropism. Unlike extant betaretroviral envelopes, which impart a narrow species tropism, we found that HERV-K ENV mediates broad tropism encompassing cells from multiple mammalian and nonmammalian species. We conclude that HERV-K ENV dictates an evolutionarily conserved entry pathway and that the restriction of HERV-K to primate genomes reflects downstream stages of the viral replication cycle. IMPORTANCE Approximately 8% of the human genome is of retroviral origin. While many of those viral genomes have become inactivated, some copies of the most recently endogenized human retrovirus, HERV-K, can encode individual functional proteins. Here, we characterize the envelope protein (ENV) of the virus to define how it mediates infection of cells. We demonstrate that HERV-K ENV undergoes a proteolytic processing step and triggers membrane fusion in response to

  10. Human Endogenous Retrovirus HERV-Fc1 Association with Multiple Sclerosis Susceptibility: A Meta-Analysis

    PubMed Central

    García-Montojo, Marta; Alcina, Antonio; Fedetz, María; Alloza, Iraide; Astobiza, Ianire; Leyva, Laura; Fernández, Oscar; Izquierdo, Guillermo; Antigüedad, Alfredo; Arroyo, Rafael; Álvarez-Lafuente, Roberto; Vandenbroeck, Koen; Matesanz, Fuencisla; Urcelay, Elena

    2014-01-01

    Background Human endogenous retroviruses (HERVs) are repetitive sequences derived from ancestral germ-line infections by exogenous retroviruses and different HERV families have been integrated in the genome. HERV-Fc1 in chromosome X has been previously associated with multiple sclerosis (MS) in Northern European populations. Additionally, HERV-Fc1 RNA levels of expression have been found increased in plasma of MS patients with active disease. Considering the North-South latitude gradient in MS prevalence, we aimed to evaluate the role of HERV-Fc1on MS risk in three independent Spanish cohorts. Methods A single nucleotide polymorphism near HERV-Fc1, rs391745, was genotyped by Taqman chemistry in a total of 2473 MS patients and 3031 ethnically matched controls, consecutively recruited from: Northern (569 patients and 980 controls), Central (883 patients and 692 controls) and Southern (1021 patients and 1359 controls) Spain. Our results were pooled in a meta-analysis with previously published data. Results Significant associations of the HERV-Fc1 polymorphism with MS were observed in two Spanish cohorts and the combined meta-analysis with previous data yielded a significant association [rs391745 C-allele carriers: pM-H = 0.0005; ORM-H (95% CI) = 1.27 (1.11–1.45)]. Concordantly to previous findings, when the analysis was restricted to relapsing remitting and secondary progressive MS samples, a slight enhancement in the strength of the association was observed [pM-H = 0.0003, ORM-H (95% CI) = 1.32 (1.14–1.53)]. Conclusion Association of the HERV-Fc1 polymorphism rs391745 with bout-onset MS susceptibility was confirmed in Southern European cohorts. PMID:24594754

  11. A survey of endogenous retrovirus (ERV) sequences in the vicinity of multiple sclerosis (MS)-associated single nucleotide polymorphisms (SNPs).

    PubMed

    Brütting, Christine; Emmer, Alexander; Kornhuber, Malte; Staege, Martin S

    2016-08-01

    Although multiple sclerosis (MS) is one of the most common central nervous system diseases in young adults, little is known about its etiology. Several human endogenous retroviruses (ERVs) are considered to play a role in MS. We are interested in which ERVs can be identified in the vicinity of MS associated genetic marker to find potential initiators of MS. We analysed the chromosomal regions surrounding 58 single nucleotide polymorphisms (SNPs) that are associated with MS identified in one of the last major genome wide association studies. We scanned these regions for putative endogenous retrovirus sequences with large open reading frames (ORFs). We observed that more retrovirus-related putative ORFs exist in the relatively close vicinity of SNP marker indices in multiple sclerosis compared to control SNPs. We found very high homologies to HERV-K, HCML-ARV, XMRV, Galidia ERV, HERV-H/env62 and XMRV-like mouse endogenous retrovirus mERV-XL. The associated genes (CYP27B1, CD6, CD58, MPV17L2, IL12RB1, CXCR5, PTGER4, TAGAP, TYK2, ICAM3, CD86, GALC, GPR65 as well as the HLA DRB1*1501) are mainly involved in the immune system, but also in vitamin D regulation. The most frequently detected ERV sequences are related to the multiple sclerosis-associated retrovirus, the human immunodeficiency virus 1, HERV-K, and the Simian foamy virus. Our data shows that there is a relation between MS associated SNPs and the number of retroviral elements compared to control. Our data identifies new ERV sequences that have not been associated with MS, so far. PMID:27169423

  12. Expression of the env gene from the avian endogenous retrovirus ALVE and regulation by miR-155.

    PubMed

    Hu, Xuming; Zhu, Wenqi; Chen, Shihao; Liu, Yangyang; Sun, Zhen; Geng, Tuoyu; Wang, Xiaoyan; Gao, Bo; Song, Chengyi; Qin, Aijian; Cui, Hengmi

    2016-06-01

    Endogenous retroviruses (ERVs) are important retroelements that reside in host genomes. However, ERV expression patterns and regulatory mechanisms are poorly understood. In this study, chicken embryo fibroblasts (CEFs) and MSB1 cells infected with Marek's disease virus (MDV) exhibited significantly increased expression of env from the endogenous retrovirus ALVE. In contrast, env expression was significantly lower in CEF and MSB1 cells infected with exogenous avian leukosis virus J (ALVJ) at the early infection stage. Furthermore, env was found to be ubiquitously expressed in various chicken tissues, with high expression in certain tissues at 2 days of age and low levels in most tissues, including immune organs (thymus, spleen and bursa) as well as the brain and heart, at 35 days of age. Sequence analysis revealed miR-155 target sites in env transcripts, which was verified using a firefly luciferase reporter assay, and treatment with miR-155 agomir significantly decreased levels of env transcripts in MSB1 and CEF cells. Together, these findings suggest that the env gene from the endogenous retrovirus ALVE is regulated by miR-155. PMID:27016933

  13. Inside the Envelope: Endogenous Retrovirus-K Env as a Biomarker and Therapeutic Target

    PubMed Central

    Nadeau, Marie-Josée; Manghera, Mamneet; Douville, Renée N.

    2015-01-01

    Due to multiple ancestral human retroviral germ cell infections, the modern human genome is strewn with relics of these infections, termed endogenous retroviruses (ERVs). ERV expression has been silenced due to negative selective pressures and genetic phenomena such as mutations and epigenetic silencing. Nonetheless, select ERVs have retained the capacity to be damaging to their host when reawakened. Much of the current research on the ERVK Env protein strongly suggests a causal or contributive role in the pathogenesis of various cancers, autoimmune and infectious diseases. Additionally, there is a small body of research suggesting that ERVK Env has been domesticated for use in placental development, akin to the ERVW syncytin. Though much is left to ascertain, the innate immune response to ERVK Env expression has been partially characterized and appears to be due to a region located in the transmembrane domain of the Env protein. In this review, we aim to highlight ERVK Env as a biomarker for inflammatory conditions and explore its use as a future therapeutic target for cancers, HIV infection and neurological disease. PMID:26617584

  14. Comparative Methylation of ERVWE1/Syncytin-1 and Other Human Endogenous Retrovirus LTRs in Placenta Tissues

    PubMed Central

    Gimenez, Juliette; Montgiraud, Cécile; Oriol, Guy; Pichon, Jean-Philippe; Ruel, Karine; Tsatsaris, Vassilis; Gerbaud, Pascale; Frendo, Jean-Louis; Evain-Brion, Danièle; Mallet, François

    2009-01-01

    Human endogenous retroviruses (HERVs) are globally silent in somatic cells. However, some HERVs display high transcription in physiological conditions. In particular, ERVWE1, ERVFRDE1 and ERV3, three proviruses of distinct families, are highly transcribed in placenta and produce envelope proteins associated with placenta development. As silencing of repeated elements is thought to occur mainly by DNA methylation, we compared the methylation of ERVWE1 and related HERVs to appreciate whether HERV methylation relies upon the family, the integration site, the tissue, the long terminal repeat (LTR) function or the associated gene function. CpG methylation of HERV-W LTRs in placenta-associated tissues was heterogeneous but a joint epigenetic control was found for ERVWE1 5′LTR and its juxtaposed enhancer, a mammalian apparent LTR retrotransposon. Additionally, ERVWE1, ERVFRDE1 and ERV3 5′LTRs were all essentially hypomethylated in cytotrophoblasts during pregnancy, but showed distinct and stage-dependent methylation profiles. In non-cytotrophoblastic cells, they also exhibited different methylation profiles, compatible with their respective transcriptional activities. Comparative analyses of transcriptional activity and LTR methylation in cell lines further sustained a role for methylation in the control of functional LTRs. These results suggest that HERV methylation might not be family related but copy-specific, and related to the LTR function and the tissue. In particular, ERVWE1 and ERV3 could be developmentally epigenetically regulated HERVs. PMID:19561344

  15. Comparative and functional studies of Drosophila species invasion by the gypsy endogenous retrovirus.

    PubMed

    Mejlumian, Lucine; Pélisson, Alain; Bucheton, Alain; Terzian, Christophe

    2002-01-01

    Gypsy is an endogenous retrovirus of Drosophila melanogaster. Phylogenetic studies suggest that occasional horizontal transfer events of gypsy occur between Drosophila species. gypsy possesses infective properties associated with the products of the envelope gene that might be at the origin of these interspecies transfers. We report here the existence of DNA sequences putatively encoding full-length Env proteins in the genomes of Drosophila species other than D. melanogaster, suggesting that potentially infective gypsy copies able to spread between sexually isolated species can occur. The ability of gypsy to invade the genome of a new species is conditioned by its capacity to be expressed in the naive genome. The genetic basis for the regulation of gypsy activity in D. melanogaster is now well known, and it has been assigned to an X-linked gene called flamenco. We established an experimental simulation of the invasion of the D. melanogaster genome by gypsy elements derived from other Drosophila species, which demonstrates that these non- D. melanogaster gypsy elements escape the repression exerted by the D. melanogaster flamenco gene. PMID:11805056

  16. Controlling Endogenous Retroviruses and Their Chimeric Transcripts During Natural Reprogramming in the Oocyte.

    PubMed

    Lim, Ai Khim; Knowles, Barbara B

    2015-07-15

    Complete genomic reprogramming happens twice during the life of a genome, once during the formation of gametes in their parents and once after their union at fertilization. For that matter complete genomic reprogramming happens twice in the same parental cell, the oocyte, when it is forming and after it matures and receives the paternal gamete. Control of these processes in this unique single cell is epigenetic, and our understanding of it is based on information gleaned from imprinting, X chromosome inactivation, and activation and silencing of endogenous retroviruses (ERV). Activation of ERVs is attributed to demethylation of chromatin and DNA, whereas silencing requires methylation, attributed to the nuage proteins, which engage the Piwi-interacting RNA pathway and other posttranscriptional mechanisms. This reprogramming process has evolved throughout speciation because in mammals, but not fish, flies and worms, nuage-component muations affect male and female gametogenesis differentially. Transcription of ERVs is derepressed in both sexes in nuage-mutant mice, but whereas males are sterile, females are fertile. Using a proteomic approach we now report molecular interactions between nuage proteins and components of the oocyte cytoplasmic lattice and speculate how this interaction could preserve ERV/host chimeric gene products affecting female fertility. PMID:26116732

  17. The distribution of pol containing human endogenous retroviruses in non-human primates.

    PubMed

    Greenwood, Alex D; Stengel, Anna; Erfle, Volker; Seifarth, Wolfgang; Leib-Mösch, Christine

    2005-04-10

    Few human endogenous retroviruses (HERVs) have been extensively studied in non-human primates. Such investigations have demonstrated that several element classes are primate unique, contain members with important biological function, are conserved in specific primate lineages, and have in some cases expanded in copy number. We have examined multiple sub-families of all major groups of HERVs using a DNA microarray based on the reverse transcriptase (RT) domain of the viral polymerase gene (pol). The microarray was used to investigate the distribution of HERVs in non-human primates with particular focus on the differences between New World monkeys (NWMs) and other anthropoids. This is the first study examining most HERV families in multiple non-human primate DNAs using a uniform and sensitive method and suggests that major differences exist between primate groups. The results indicate that a major invasion and expansion of pol containing HERVs occurred after the platyrrhine (NWM) lineage separated from the catarrhines (Old World Monkeys and apes). PMID:15780870

  18. Inside the Envelope: Endogenous Retrovirus-K Env as a Biomarker and Therapeutic Target.

    PubMed

    Nadeau, Marie-Josée; Manghera, Mamneet; Douville, Renée N

    2015-01-01

    Due to multiple ancestral human retroviral germ cell infections, the modern human genome is strewn with relics of these infections, termed endogenous retroviruses (ERVs). ERV expression has been silenced due to negative selective pressures and genetic phenomena such as mutations and epigenetic silencing. Nonetheless, select ERVs have retained the capacity to be damaging to their host when reawakened. Much of the current research on the ERVK Env protein strongly suggests a causal or contributive role in the pathogenesis of various cancers, autoimmune and infectious diseases. Additionally, there is a small body of research suggesting that ERVK Env has been domesticated for use in placental development, akin to the ERVW syncytin. Though much is left to ascertain, the innate immune response to ERVK Env expression has been partially characterized and appears to be due to a region located in the transmembrane domain of the Env protein. In this review, we aim to highlight ERVK Env as a biomarker for inflammatory conditions and explore its use as a future therapeutic target for cancers, HIV infection and neurological disease. PMID:26617584

  19. (Some) Cellular Mechanisms Influencing the Transcription of Human Endogenous Retrovirus, HERV-Fc1

    PubMed Central

    Laska, Magdalena Janina; Nissen, Kari Konstantin; Nexø, Bjørn Andersen

    2013-01-01

    DNA methylation and histone acetylation are epigenetic modifications that act as regulators of gene expression. DNA methylation is considered an important mechanism for silencing of retroelements in the mammalian genome. However, the methylation of human endogenous retroviruses (HERVs) is not well investigated. The aim of this study was to investigate the transcriptional potential of HERV-Fc1 proviral 5′LTR in more detail, and examined the specific influence of CpG methylation on this LTR in number of cell lines. Specifically, the role of demethylating chemicals e.g. 5-aza-2′ deoxycytidine and Trichostatin-A, in inducing or reactivating expression of HERV-Fc1 specific sequences and the mechanisms were investigated. In our present study, 5-aza-dC is shown to be a powerful inducer of HERV-Fc1, and at the same time it strongly inhibits methylation of DNA. Treatment with this demethylating agent 5-aza-dC, results in significantly increased levels of HERV-Fc1 expression in cells previously not expressing HERV-Fc1, or with a very low expression level. The extent of expression of HERV-Fc1 RNAs precisely correlates with the apparent extent of demethylation of the related DNA sequences. In conclusion, the results suggest that inhibition of DNA methylation/histone deacetylase can interfere with gene silencing mechanisms affecting HERV-Fc1 expression in human cells. PMID:23382858

  20. Evolutionary dynamics of endogenous Jaagsiekte sheep retroviruses proliferation in the domestic sheep, mouflon and Pyrenean chamois

    PubMed Central

    Sistiaga-Poveda, M; Jugo, B M

    2014-01-01

    The oncogenic exogenous Jaagsiekte sheep retrovirus (JSRV), responsible for ovine pulmonary adenocarcinoma, has several endogenous counterparts termed enJSRVs. Although many of these elements have been inactivated over time by the accumulation of deleterious mutations or internal recombination leading to solo long terminal repeat (LTR) formation, several members of enJSRVs have been identified as nearly intact and probably represent recent integration events. To determine the level of enJSRV polymorphism in the sheep population and related species, we have undertaken a study by characterizing enJSRVs copies and independent integration sites in six domestic sheep and two wild species of the sheep lineage. enJSRVs copies were detected by amplifying the env-LTR region by PCR, and for the detection of the insertion sites, we used two approaches: (1) an in silico approach based on the recently published Sheep Reference Genome Assembly (OARv3.0) and (2) an experimental approach based on PCR suppression and inverse PCR techniques. In total, 103 enJSRV sequences were generated across 10 individuals and enJSRV integrations were found on 11 of the 28 sheep chromosomes. These findings suggest that there are still uncharacterized enJSRVs, and that some of the integration sites are variable among the different species, breeds of the same species, subspecies and geographic locations. PMID:24690757

  1. Porcine endogenous retrovirus-A/C: biochemical properties of its integrase and susceptibility to raltegravir.

    PubMed

    Demange, Antonin; Yajjou-Hamalian, Halima; Gallay, Kathy; Luengo, Catherine; Beven, Véronique; Leroux, Aurélie; Confort, Marie-Pierre; Al Andary, Elsy; Gouet, Patrice; Moreau, Karen; Ronfort, Corinne; Blanchard, Yannick

    2015-10-01

    Porcine endogenous retroviruses (PERVs) are present in the genomes of pig cells. The PERV-A/C recombinant virus can infect human cells and is a major risk of zoonotic disease in the case of xenotransplantation of pig organs to humans. Raltegravir (RAL) is a viral integrase (IN) inhibitor used in highly active antiretroviral treatment. In the present study, we explored the potential use of RAL against PERV-A/C. We report (i) a three-dimensional model of the PERV-A/C intasome complexed with RAL, (ii) the sensitivity of PERV-A/C IN to RAL in vitro and (iii) the sensitivity of a PERV-A/C-IRES-GFP recombinant virus to RAL in cellulo. We demonstrated that RAL is a potent inhibitor against PERV-A/C IN and PERV-A/C replication with IC50s in the nanomolar range. To date, the use of retroviral inhibitors remains the only way to control the risk of zoonotic PERV infection during pig-to-human xenotransplantation. PMID:26296914

  2. Age-related reduction of antibody response against the human endogenous retrovirus K envelope in women

    PubMed Central

    Lee, Jun Woo; Kim, Seung Cheol; Kim, Hong-Jin

    2016-01-01

    In the present study, the correlation between the antibody response against human endogenous retrovirus K (HERV-K) envelope and human age was investigated. Antibody levels were compared in groups in their 20s (n = 25), 30s (n = 39), 40s (n = 68), 50s (n = 32), and 60s and over (n = 25), which included healthy individuals and breast cancer and/or cervical cancer patients. It appeared that both IgM and IgG responses against the HERV-K envelope fell with increasing age. There were no differences in anti-HERV-K envelope antibody levels between healthy individuals and cancer patients. Therefore, our results indicated that the anti-HERV-K antibody levels cannot be considered as cancer-specific marker. Also, IgG1 appeared to be the predominant subtype in the reduction of the IgG response by age. Receiver operating characteristic curves of anti-HERV-K envelope IgM levels indicated that the groups of people in their 20s or 30s could be distinguished from those in their 40s, 50s or 60s and over with satisfactory sensitivity and specificity. These findings indicate that the serum antibody level of HERV-K envelope is a critical parameter reflecting person's age. PMID:26872058

  3. Human endogenous retrovirus envelope proteins target dendritic cells to suppress T-cell activation.

    PubMed

    Hummel, Jonas; Kämmerer, Ulrike; Müller, Nora; Avota, Elita; Schneider-Schaulies, Sibylle

    2015-06-01

    Though mostly defective, human endogenous retroviruses (HERV) can retain open reading frames, which are especially expressed in the placenta. There, the envelope (env) proteins of HERV-W (Syncytin-1), HERV-FRD (Syncytin-2), and HERV-K (HML-2) were implicated in tolerance against the semi-allogenic fetus. Here, we show that the known HERV env-binding receptors ASCT-1 and -2 and MFSD2 are expressed by DCs and T-cells. When used as effectors in coculture systems, CHO cells transfected to express Syncytin-1, -2, or HML-2 did not affect T-cell expansion or overall LPS-driven phenotypic DC maturation, however, promoted release of IL-12 and TNF-α rather than IL-10. In contrast, HERV env expressing choriocarcinoma cell lines suppressed T-cell proliferation and LPS-induced TNF-α and IL-12 release, however, promoted IL-10 accumulation, indicating that these effects might not rely on HERV env interactions. However, DCs conditioned by choriocarcinoma, but also transgenic CHO cells failed to promote allogenic T-cell expansion. This was associated with a loss of DC/T-cell conjugate frequencies, impaired Ca(2+) mobilization, and aberrant patterning of f-actin and tyrosine phosphorylated proteins in T-cells. Altogether, these findings suggest that HERV env proteins target T-cell activation indirectly by modulating the stimulatory activity of DCs. PMID:25752285

  4. Expression of Human Endogenous Retrovirus env Genes in the Blood of Breast Cancer Patients

    PubMed Central

    Rhyu, Dong-Won; Kang, Yun-Jeong; Ock, Mee-Sun; Eo, Jung-Woo; Choi, Yung-Hyun; Kim, Wun-Jae; Leem, Sun-Hee; Yi, Joo-Mi; Kim, Heui-Soo; Cha, Hee-Jae

    2014-01-01

    Human endogenous retroviruses (HERV) env proteins have been recently reported to be significantly up-regulated in certain cancers. Specifically, mRNA and protein levels of HERV-K (HML-2) are up-regulated in the blood plasma or serum of breast cancer patients. Here, we collected blood samples of 49 breast cancer patients and analyzed mRNA expressions of various HERVs env genes including HERV-R, HERV-H, HERV-K, and HERV-P by real-time PCR. The expression of env genes were significantly increased in the blood of primary breast cancer patients but were decreased in patients undergoing chemotherapy to a similar level with benign patients. When we compared the group currently undergoing chemotherapy and those patients undergoing chemotherapy simultaneously with radiotherapy, HERVs env genes were reduced more in the chemotherapy only group, suggesting that chemotherapy is more effective in reducing HERV env gene expression than is radiotherapy. Among chemotherapy groups, HERV env gene expression was the lowest in the taxotere- or taxol-treated group, suggesting that taxotere and taxol can reduce HERVs env expression. These data suggest the potential to use HERVs env genes as a diagnosis marker for primary breast cancer, and further studies are needed to identify the mechanism and physiological significance of the reduction of HERV env gene expression during chemotherapy. PMID:24964007

  5. Genotyping of Porcine Endogenous Retroviruses from a Family of Miniature Swine

    PubMed Central

    Quinn, Gary; Wood, James; Suling, Kristen; Arn, Scott; Sachs, David H.; Schuurman, Henk-Jan; Patience, Clive

    2004-01-01

    The identification of animals in an inbred miniature swine herd that consistently fail to produce replication- competent humantropic porcine endogenous retrovirus (PERV) has prompted studies on the biology of PERV in transmitter and nontransmitter animals. We analyzed PERV RNA transcript profiles in a family of inbred miniature swine (SLAd/d haplotype) in which individual members differed in their capacity to generate humantropic and ecotropic (i.e., pigtropic) virus. We identified unique HaeIII and HpaII gag restriction fragment length polymorphism (RFLP) profiles resulting from single nucleotide polymorphisms in blood cells; these were found only in animals that produced humantropic PERV. These HaeIII and HpaII gag RFLP profiles proved to be components of humantropic PERV as they were transmitted to 293 human target cells in vitro. The humantropic HaeIII and HpaII gag RFLP genotypes in the family of study were not present in other miniature swine in the herd that produced humantropic PERV, indicating that these RFLP profiles relate specifically to this family's lineage. PMID:14671113

  6. Mice Transgenic for a Human Porcine Endogenous Retrovirus Receptor Are Susceptible to Productive Viral Infection†

    PubMed Central

    Martina, Y.; Marcucci, K. T.; Cherqui, S.; Szabo, A.; Drysdale, T.; Srinivisan, U.; Wilson, C. A.; Patience, C.; Salomon, D. R.

    2006-01-01

    Porcine endogenous retrovirus (PERV) is considered one of the major risks in xenotransplantation. No valid animal model has been established to evaluate the risks associated with PERV transmission to human patients by pig tissue xenotransplantation or to study the potential pathogenesis associated with PERV infection. In previous work we isolated two genes encoding functional human PERV receptors and proved that introduction of these into mouse fibroblasts allowed the normally nonpermissive mouse cells to become productively infected (T. A. Ericsson, Y. Takeuchi, C. Templin, G. Quinn, S. F. Farhadian, J. C. Wood, B. A. Oldmixon, K. M. Suling, J. K. Ishii, Y. Kitagawa, T. Miyazawa, D. R. Salomon, R. A. Weiss, and C. Patience, Proc. Natl. Acad. Sci. USA 100:6759-6764, 2003). In the present study we created mice transgenic for human PERV-A receptor 2 (HuPAR-2). After inoculation of transgenic animals with infectious PERV supernatants, viral DNA and RNA were detected at multiple time points, indicating productive replication. This establishes the role of HuPAR-2 in PERV infection in vivo; in addition, these transgenic mice represent a new model for determining the risk of PERV transmission and potential pathogenesis. These mice also create a unique opportunity to study the immune response to PERV infection and test potential therapeutic or preventative modalities. PMID:16537582

  7. Susceptibility of the Porcine Endogenous Retrovirus to Reverse Transcriptase and Protease Inhibitors

    PubMed Central

    Qari, Shoukat H.; Magre, Saema; García-Lerma, J. Gerardo; Hussain, Althaf I.; Takeuchi, Yasuhiro; Patience, Clive; Weiss, Robin A.; Heneine, Walid

    2001-01-01

    Porcine xenografts may offer a solution to the shortage of human donor allografts. However, all pigs contain the porcine endogenous retrovirus (PERV), raising concerns regarding the transmission of PERV and the possible development of disease in xenotransplant recipients. We evaluated 11 antiretroviral drugs licensed for human immunodeficiency virus type 1 (HIV-1) therapy for their activities against PERV to assess their potential for clinical use. Fifty and 90% inhibitory concentrations (IC50s and IC90s, respectively) of five nucleoside reverse transcriptase inhibitors (RTIs) were determined enzymatically for PERV and for wild-type (WT) and RTI-resistant HIV-1 reference isolates. In a comparison of IC50s, the susceptibilities of PERV RT to lamivudine, stavudine, didanosine, zalcitabine, and zidovudine were reduced >20-fold, 26-fold, 6-fold, 4-fold, and 3-fold, respectively, compared to those of WT HIV-1. PERV was also resistant to nevirapine. Tissue culture-based, single-round infection assays using replication-competent virus confirmed the relative sensitivity of PERV to zidovudine and its resistance to all other RTIs. A Gag polyprotein-processing inhibition assay was developed and used to assess the activities of protease inhibitors against PERV. No inhibition of PERV protease was seen with saquinavir, ritonavir, indinavir, nelfinavir, or amprenavir at concentrations >200-fold the IC50s for WT HIV-1. Thus, following screening of many antiretroviral agents, our findings support only the potential clinical use of zidovudine. PMID:11134319

  8. Porcine Endogenous Retrovirus Transmission Characteristics of Galactose α1-3 Galactose-Deficient Pig Cells

    PubMed Central

    Quinn, Gary; Wood, James C.; Ryan, David J. J.; Suling, Kristen M.; Moran, Kathleen M.; Kolber-Simonds, Donna L.; Greenstein, Julia L.; Schuurman, Henk-Jan; Hawley, Robert J.; Patience, Clive

    2004-01-01

    Galactose α1-3 galactose (Gal) trisaccharides are present on the surface of wild-type pig cells, as well as on viruses particles produced from such cells. The recognition of Gal sugars by natural anti-Gal antibodies (NAb) in human and Old World primate serum can cause the lysis of the particles via complement-dependent mechanisms and has therefore been proposed as an important antiviral mechanism. Recently, pigs have been generated that possess disrupted galactosyl-transferase (GGTA1) genes. The cells of these pigs do not express Gal sugars on their surface, i.e., are Gal null. Concerns have been raised that the risk of virus transmission from such pigs may be increased due to the absence of the Gal sugars. We investigated the sensitivity of porcine endogenous retrovirus (PERV) produced from Gal-null and Gal-positive pig cells to inactivation by purified NAb and human serum. PERV produced in Gal-null pig cells was resistant to inactivation by either NAb or human serum. In contrast, although Gal-positive PERV particles were sensitive to inactivation by NAb and human serum, they required markedly higher concentrations of NAb for inactivation compared to the Gal-positive cells from which they were produced. Complete inactivation of Gal-positive PERV particles was not achievable despite the use of high levels of NAb, indicating that NAb-mediated inactivation of cell-free PERV particles is an inefficient process. PMID:15140978

  9. Expression of Human Endogenous Retrovirus-W Including Syncytin-1 in Cutaneous T-Cell Lymphoma

    PubMed Central

    Maliniemi, Pilvi; Vincendeau, Michelle; Mayer, Jens; Frank, Oliver; Hahtola, Sonja; Karenko, Leena; Carlsson, Emilia; Mallet, Francois; Seifarth, Wolfgang; Leib-Mösch, Christine; Ranki, Annamari

    2013-01-01

    The pathomechanism of mycosis fungoides (MF), the most common type of primary cutaneous T-cell lymphomas (CTCLs) and a malignancy of non-recirculating, skin-resident T-cells, is unknown albeit underlying viral infections have been sought for. Human endogenous retroviruses (HERVs) are ancient retroviral sequences in the human genome and their transcription is often deregulated in cancers. We explored the transcriptional activity of HERV sequences in a total of 34 samples comprising MF and psoriasis skin lesions, as well as corresponding non-malignant skin using a retrovirus-specific microarray and quantitative RT-PCR. To identify active HERV-W loci, we cloned the HERV-W specific RT-PCR products, sequenced the cDNA clones and assigned the sequences to HERV-W loci. Finally, we used immunohistochemistry on MF patient and non-malignant inflammatory skin samples to confirm specific HERV-encoded protein expression. Firstly, a distinct, skin-specific transcription profile consisting of five constitutively active HERV groups was established. Although individual variability was common, HERV-W showed significantly increased transcription in MF lesions compared to clinically intact skin from the same patient. Predominantly transcribed HERV-W loci were found to be located in chromosomes 6q21 and 7q21.2, chromosomal regions typically altered in CTCL. Surprisingly, we also found the expression of 7q21.2/ERVWE1-encoded Syncytin-1 (Env) protein in MF biopsies and expression of Syncytin-1 was seen in malignant lymphocytes, especially in the epidermotropic ones, in 15 of 30 cases studied. Most importantly, no Syncytin-1 expression was detected in inflammatory dermatosis (Lichen ruber planus) with skin-homing, non-malignant T lymphocytes. The expression of ERVWE1 mRNA was further confirmed in 3/7 MF lesions analyzed. Our observations strengthen the association between activated HERVs and cancer. The study offers a new perspective into the pathogenesis of CTCL since we demonstrate

  10. Murine retroviruses activate B cells via interaction with toll-like receptor 4

    PubMed Central

    Rassa, John C.; Meyers, Jennifer L.; Zhang, Yuanming; Kudaravalli, Rama; Ross, Susan R.

    2002-01-01

    Although most retroviruses require activated cells as their targets for infection, it is not known how this is achieved in vivo. A candidate protein for the activation of B cells by either mouse mammary tumor virus (MMTV) or murine leukemia virus is the toll-like receptor 4 (TLR4), a component of the innate immune system. MMTV caused B cell activation in C3H/HeN mice but not in C3H/HeJ or BALB/c (C.C3H Tlr4lps-d) congenic mice, both of which have a mutant TLR4 gene. This activation was independent of viral gene expression, because it occurred after treatment of MMTV with ultraviolet light or 2,2′-dithiodipyridine and in azidothymidine-treated mice. Nuclear extracts prepared from the lymphocytes of MMTV-injected C3H/HeN but not C3H/HeJ mice showed increased nuclear factor κB activity. Additionally, the MMTV- and Moloney murine leukemia virus envelope proteins coimmunoprecipitated with TLR4 when expressed in 293T cells. The MMTV receptor failed to coimmunoprecipitate with TLR4, suggesting that MMTV/TLR4 interaction is independent of virus attachment and fusion. These results identify retroviral proteins that interact with a mammalian toll receptor and show that direct activation by such viruses may initiate in vivo infection pathways. PMID:11854525

  11. 'Solo' large terminal repeats (LTR) of an endogenous retrovirus-like gene family (VL30) in the mouse genome.

    PubMed Central

    Rotman, G; Itin, A; Keshet, E

    1984-01-01

    VL30 genetic elements constitute a murine multicopy gene family that is retrovirus-like, despite the lack of sequence homology with any known retrovirus. Over one hundred copies of VL30 units are dispersed throughout the mouse genome. We report here that the mouse genome also contains 'solo' VL30 long terminal repeats (LTRs). These are structures which contain the LTR detached from the rest of the VL30 sequences. The isolation of solo LTRs from a mouse embryonic gene library with the aid of sub-genomic VL30 probes is described. Direct DNA sequencing established that the solo LTR unit is grossly similar to a standard VL30 LTR and that the LTR is flanked by a 4-base pair duplication. The analogy to the occurrence of solitary LTR units of transposable elements is discussed. Images PMID:6324110

  12. Nonrandom chromosomal change (trisomy 11) in murine plasmacytomas induced by an ABL-MYC retrovirus.

    PubMed

    Wiener, F; Coleman, A; Mock, B A; Potter, M

    1995-03-01

    Trisomy of chromosome 11 (Ts11) is the second most frequent nonrandom chromosomal change in murine plasmacytomas (PCTs). The frequency of Ts11 is significantly higher in PCTs induced in pristane-conditioned mice infected by Abelson-murine leukemia virus (52%) compared to those induced by pristane alone (8.1%). Although the significance of Ts11 in mouse plasmacytomagenesis is not clearly understood it is hypothesized that a gene or genes located on chromosome (Chr) 11 may specifically promote the development of PCTs in which both oncogenes, c-myc and v-abl, are abundantly expressed. To test this assumption we induced PCTs by three highly effective plasmacytomagenic retroviruses: ABL-MYC, J3V1, and RIM. Nearly 90% of PCTs that arose in BALB/c, (BALB/c x DBA/2N)F1, BALB/c-nu/nu, and 5-month-old SCID mice infected with ABL-MYC virus were trisomic for Chr 11. In contrast, < 10% of PCTs induced by J3V1 or RIM retroviral constructs encompassing either v-myc and v-raf or c-myc and v-Ha-ras oncogenes, respectively, contained Ts11. We have also investigated whether the entire Chr 11 or any particular subregion is preferentially duplicated in the process of ABL-MYC plasmacytomagenesis. By inducing PCTs in F1 heterozygous mice that are carriers of reciprocal translocations involving Chr 11 we found that the duplicated chromosomal region is located distal to the T4Dn breakpoint (11B5 band) on the telomeric segment of Chr 11. The regular duplication of this chromosomal segment strongly suggests the presence of a gene or genes whose amplification is of critical importance for v-abl associated murine plasmacytomagenesis. PMID:7867005

  13. Identification and characterization of two closely related unclassifiable endogenous retroviruses in pythons (Python molurus and Python curtus).

    PubMed

    Huder, Jon B; Böni, Jürg; Hatt, Jean-Michel; Soldati, Guido; Lutz, Hans; Schüpbach, Jörg

    2002-08-01

    Boid inclusion body disease (BIBD) is a fatal disorder of boid snakes that is suspected to be caused by a retrovirus. In order to identify this agent, leukocyte cultures (established from Python molurus specimens with symptoms of BIBD or kept together with such diseased animals) were assessed for reverse transcriptase (RT) activity. Virus from cultures exhibiting high RT activity was banded on sucrose density gradients, and the RT peak fraction was subjected to highly efficient procedures for the identification of unknown particle-associated retroviral RNA. A 7-kb full retroviral sequence was identified, cloned, and sequenced. This virus contained intact open reading frames (ORFs) for gag, pro, pol, and env, as well as another ORF of unknown function within pol. Phylogenetic analysis showed that the virus is distantly related to viruses from both the B and D types and the mammalian C type but cannot be classified. It is present as a highly expressed endogenous retrovirus in all P. molurus individuals; a closely related, but much less expressed virus was found in all tested Python curtus individuals. All other boid snakes tested, including Python regius, Python reticulatus, Boa constrictor, Eunectes notaeus, and Morelia spilota, were virus negative, independent of whether they had BIBD or not. Virus isolated from P. molurus could not be transmitted to the peripheral blood mononuclear cells of B. constrictor or P. regius. Thus, there is no indication that this novel virus, which we propose to name python endogenous retrovirus (PyERV), is causally linked with BIBD. PMID:12097574

  14. Direct determination of the point mutation rate of a murine retrovirus.

    PubMed Central

    Monk, R J; Malik, F G; Stokesberry, D; Evans, L H

    1992-01-01

    The point mutation rate of a murine leukemia virus (MuLV) genome (AKV) was determined under conditions in which the number of replicative cycles was carefully controlled and the point mutation rate was determined by direct examination of the RNA genomes of progeny viruses. A clonal cell line infected at a low multiplicity of infection (2 x 10(-3)) was derived to provide a source of virus with high genetic homogeneity. Virus stocks from this cell line were used to infect cells at a low multiplicity of infection, and the cells were seeded soon after infection to obtain secondary clonal cell lines. RNase T1-oligonucleotide fingerprinting analyses of virion RNAs from 93 secondary lines revealed only 3 base changes in nearly 130,000 bases analyzed. To obtain an independent assessment of the mutation rate, we directly sequenced virion RNAs by using a series of DNA oligonucleotide primers distributed across the genome. RNA sequencing detected no mutations in over 21,000 bases analyzed. The combined fingerprinting and sequencing analyses yielded a mutation rate for infectious progeny viruses of one base change per 50,000 (2 x 10(-5)) bases per replication cycle. Our results suggest that over 80% of infectious progeny MuLVs may be replicated with complete fidelity and that only a low percentage undergo more than one point mutation during a replication cycle. Previous estimates of retroviral mutation rates suggest that the majority of infectious progeny viruses have undergone one or more point mutations. Recent studies of the mutation rates of marker genes in spleen necrosis virus-based vectors estimate a base substitution rate lower than estimates for infectious avian retroviruses and nearly identical to our determinations with AKV. The differences between mutation rates observed in studies of retroviruses may reflect the imposition of different selective conditions. Images PMID:1316475

  15. Screening pigs for xenotransplantation: expression of porcine endogenous retroviruses in transgenic pig skin.

    PubMed

    Kimsa-Dudek, Magdalena; Strzalka-Mrozik, Barbara; Kimsa, Malgorzata W; Blecharz, Irena; Gola, Joanna; Skowronek, Bartlomiej; Janiszewski, Adrian; Lipinski, Daniel; Zeyland, Joanna; Szalata, Marlena; Slomski, Ryszard; Mazurek, Urszula

    2015-06-01

    Pigs seem to be the answer to worldwide organ donor shortage. Porcine skin may also be applied as a dressing for severe burns. Genetic modifications of donor animals enable reduction of immune response, which prolongs xenograft survival as temporary biological dressing and allows achieving resistance against xenograft rejection. The risk posed by porcine endogenous retroviruses (PERVs) cannot be eliminated by breeding animals under specific-pathogen-free conditions and so all recipients of porcine graft will be exposed to PERVs. Therefore our study has been focused on the assessment of PERV DNA and mRNA level in skin samples of transgenic pigs generated for xenotransplantation. Porcine skin fragments were obtained from 3- to 6-month-old non-transgenic and transgenic Polish Landrace pigs. Transgenic pigs were produced by pronuclear DNA microinjection and were developed to express the human α-galactosidase and the human α-1,2-fucosyltransferase gene. The copy numbers of PERV DNA and RNA were evaluated using real-time Q-PCR and QRT-PCR. Comparative analysis of all PERV subtypes revealed that PERV-A is the main subtype of PERVs in analyzed skin samples. There was no significantly different copy number of PERV-A, PERV-B and PERV-C between non-transgenic pigs, pigs with the human α-galactosidase and pigs expressing the human α-1,2-fucosyltransferase gene, except of PERV-C DNA. It brings the conclusion, that transgenesis process exerts no influence on PERVs transinfection. That is another step forward in the development of pig skin xenografts as burn wounds dressing. PMID:25812516

  16. Protective effect of human endogenous retrovirus K dUTPase variants on psoriasis susceptibility.

    PubMed

    Lai, Olivia Y; Chen, Haoyan; Michaud, Henri-Alexandre; Hayashi, Genki; Kuebler, Peter J; Hultman, Gustaf K; Ariza, Maria-Eugenia; Williams, Marshall V; Batista, Mariana D; Nixon, Douglas F; Foerster, John; Bowcock, Anne M; Liao, Wilson

    2012-07-01

    Previous genetic and functional studies have implicated the human endogenous retrovirus K (HERV-K) dUTPase located within the PSORS1 locus in the major histocompatibility complex region as a candidate psoriasis gene. Here, we describe a variant discovery and case-control association study of HERV-K dUTPase variants in 708 psoriasis cases and 349 healthy controls. Five common HERV-K dUTPase variants were found to be highly associated with psoriasis, with the strongest association occurring at the missense single-nucleotide polymorphism (SNP) rs3134774 (K158R, P=3.28 × 10(-15), odds ratio =2.36 (95% confidence interval: 1.91-2.92)). After adjusting the association of the HERV-K dUTPase variants for the potential confounding effects of HLA alleles associated with psoriasis, the HERV-K SNPs rs9264082 and rs3134774 remained significantly associated. Haplotype analysis revealed that HERV-K haplotypes containing the non-risk alleles for rs3134774 and rs9264082 significantly reduced the risk of psoriasis. Functional testing showed higher antibody responses against recombinant HERV-K dUTPase in psoriasis patients compared with controls (P<0.05), as well as higher T-cell responses against a single HERV-K dUTPase peptide (P<0.05). Our data support an independent role for the HERV-K dUTPase on psoriasis susceptibility, and suggest the need for additional studies to clarify the role of this dUTPase in the pathogenesis of psoriasis. PMID:22437317

  17. Protective Effect of Human Endogenous Retrovirus K dUTPase Variants on Psoriasis Susceptibility

    PubMed Central

    Lai, Olivia Y.; Chen, Haoyan; Michaud, Henri-Alexandre; Hayashi, Genki; Kuebler, Peter J.; Hultman, Gustaf K.; Ariza, Maria-Eugenia; Williams, Marshall V.; Batista, Mariana D.; Nixon, Douglas F.; Foerster, John; Bowcock, Anne M.; Liao, Wilson

    2012-01-01

    Previous genetic and functional studies have implicated the human endogenous retrovirus K (HERV-K) dUTPase located within the PSORS1 locus in the MHC region as a candidate psoriasis gene. Here, we describe a variant discovery and case-control association study of HERV-K dUTPase variants in 708 psoriasis cases and 349 healthy controls. Five common HERV-K dUTPase variants were found to be highly associated with psoriasis, with the strongest association occurring at the missense SNP rs3134774 (K158R, p=3.28 × 10-15, OR=2.36 [1.91-2.92]). After adjusting the association of the HERV-K dUTPase variants for the potential confounding effects of HLA alleles associated with psoriasis, the HERV-K SNPs rs9264082 and rs3134774 remained significantly associated. Haplotype analysis revealed that HERV-K haplotypes containing the non-risk alleles for rs3134774 and rs9264082 significantly reduced the risk of psoriasis. Functional testing showed higher antibody responses against recombinant HERV-K dUTPase in psoriasis patients compared to controls (p<0.05), as well as higher T-cell responses against a single HERV-K dUTPase peptide (p<0.05). Our data support an independent role for the HERV-K dUTPase on psoriasis susceptibility, and suggest the need for additional studies to clarify the role of this dUTPase in the pathogenesis of psoriasis. PMID:22437317

  18. Integration and Fixation Preferences of Human and Mouse Endogenous Retroviruses Uncovered with Functional Data Analysis

    PubMed Central

    Pini, Alessia; Chiaromonte, Francesca; Makova, Kateryna D.

    2016-01-01

    Endogenous retroviruses (ERVs), the remnants of retroviral infections in the germ line, occupy ~8% and ~10% of the human and mouse genomes, respectively, and affect their structure, evolution, and function. Yet we still have a limited understanding of how the genomic landscape influences integration and fixation of ERVs. Here we conducted a genome-wide study of the most recently active ERVs in the human and mouse genome. We investigated 826 fixed and 1,065 in vitro HERV-Ks in human, and 1,624 fixed and 242 polymorphic ETns, as well as 3,964 fixed and 1,986 polymorphic IAPs, in mouse. We quantitated >40 human and mouse genomic features (e.g., non-B DNA structure, recombination rates, and histone modifications) in ±32 kb of these ERVs’ integration sites and in control regions, and analyzed them using Functional Data Analysis (FDA) methodology. In one of the first applications of FDA in genomics, we identified genomic scales and locations at which these features display their influence, and how they work in concert, to provide signals essential for integration and fixation of ERVs. The investigation of ERVs of different evolutionary ages (young in vitro and polymorphic ERVs, older fixed ERVs) allowed us to disentangle integration vs. fixation preferences. As a result of these analyses, we built a comprehensive model explaining the uneven distribution of ERVs along the genome. We found that ERVs integrate in late-replicating AT-rich regions with abundant microsatellites, mirror repeats, and repressive histone marks. Regions favoring fixation are depleted of genes and evolutionarily conserved elements, and have low recombination rates, reflecting the effects of purifying selection and ectopic recombination removing ERVs from the genome. In addition to providing these biological insights, our study demonstrates the power of exploiting multiple scales and localization with FDA. These powerful techniques are expected to be applicable to many other genomic investigations

  19. Review on porcine endogenous retrovirus detection assays--impact on quality and safety of xenotransplants.

    PubMed

    Godehardt, Antonia W; Rodrigues Costa, Michael; Tönjes, Ralf R

    2015-01-01

    Xenotransplantation of porcine organs, tissues, and cells inherits a risk for xenozoonotic infections. Viable tissues and cells intended for transplantation have to be considered as potentially contaminated non-sterile products. The demands on microbial testing, based on the regulatory requirements, are often challenging due to a restricted shelf life or the complexity of the product itself. In Europe, the regulatory framework for xenogeneic cell therapy is based on the advanced therapy medicinal products (ATMP) regulation (2007), the EMA CHMP Guideline on xenogeneic cell-based medicinal products (2009), as well as the WHO and Council of Europe recommendations. In the USA, FDA guidance for industry (2003) regulates the use of xenotransplants. To comply with the regulations, validated test methods need to be established that reveal the microbial status of a transplant within its given shelf life, complemented by strictly defined action alert limits and supported by breeding in specific pathogen-free (SPF) facilities. In this review, we focus on assays for the detection of the porcine endogenous retroviruses PERV-A/-B/-C, which exhibit highly polymorphic proviral loci in pig genomes. PERVs are transmitted vertically and cannot be completely eliminated by breeding or gene knock out technology. PERVs entail a public health concern that will persist even if no evidence of PERV infection of xenotransplant recipients in vivo has been revealed yet. Nevertheless, infectious risks must be minimized by full assessment of pigs as donors by combining different molecular screening assays for sensitive and specific detection as well as a functional analysis of the infectivity of PERV including an adequate monitoring of recipients. PMID:25641488

  20. Review on porcine endogenous retrovirus detection assays—impact on quality and safety of xenotransplants

    PubMed Central

    Godehardt, Antonia W; Rodrigues Costa, Michael; Tönjes, Ralf R

    2015-01-01

    Xenotransplantation of porcine organs, tissues, and cells inherits a risk for xenozoonotic infections. Viable tissues and cells intended for transplantation have to be considered as potentially contaminated non-sterile products. The demands on microbial testing, based on the regulatory requirements, are often challenging due to a restricted shelf life or the complexity of the product itself. In Europe, the regulatory framework for xenogeneic cell therapy is based on the advanced therapy medicinal products (ATMP) regulation (2007), the EMA CHMP Guideline on xenogeneic cell-based medicinal products (2009), as well as the WHO and Council of Europe recommendations. In the USA, FDA guidance for industry (2003) regulates the use of xenotransplants. To comply with the regulations, validated test methods need to be established that reveal the microbial status of a transplant within its given shelf life, complemented by strictly defined action alert limits and supported by breeding in specific pathogen-free (SPF) facilities. In this review, we focus on assays for the detection of the porcine endogenous retroviruses PERV-A/-B/-C, which exhibit highly polymorphic proviral loci in pig genomes. PERVs are transmitted vertically and cannot be completely eliminated by breeding or gene knock out technology. PERVs entail a public health concern that will persist even if no evidence of PERV infection of xenotransplant recipients in vivo has been revealed yet. Nevertheless, infectious risks must be minimized by full assessment of pigs as donors by combining different molecular screening assays for sensitive and specific detection as well as a functional analysis of the infectivity of PERV including an adequate monitoring of recipients. PMID:25641488

  1. Integration and Fixation Preferences of Human and Mouse Endogenous Retroviruses Uncovered with Functional Data Analysis.

    PubMed

    Campos-Sánchez, Rebeca; Cremona, Marzia A; Pini, Alessia; Chiaromonte, Francesca; Makova, Kateryna D

    2016-06-01

    Endogenous retroviruses (ERVs), the remnants of retroviral infections in the germ line, occupy ~8% and ~10% of the human and mouse genomes, respectively, and affect their structure, evolution, and function. Yet we still have a limited understanding of how the genomic landscape influences integration and fixation of ERVs. Here we conducted a genome-wide study of the most recently active ERVs in the human and mouse genome. We investigated 826 fixed and 1,065 in vitro HERV-Ks in human, and 1,624 fixed and 242 polymorphic ETns, as well as 3,964 fixed and 1,986 polymorphic IAPs, in mouse. We quantitated >40 human and mouse genomic features (e.g., non-B DNA structure, recombination rates, and histone modifications) in ±32 kb of these ERVs' integration sites and in control regions, and analyzed them using Functional Data Analysis (FDA) methodology. In one of the first applications of FDA in genomics, we identified genomic scales and locations at which these features display their influence, and how they work in concert, to provide signals essential for integration and fixation of ERVs. The investigation of ERVs of different evolutionary ages (young in vitro and polymorphic ERVs, older fixed ERVs) allowed us to disentangle integration vs. fixation preferences. As a result of these analyses, we built a comprehensive model explaining the uneven distribution of ERVs along the genome. We found that ERVs integrate in late-replicating AT-rich regions with abundant microsatellites, mirror repeats, and repressive histone marks. Regions favoring fixation are depleted of genes and evolutionarily conserved elements, and have low recombination rates, reflecting the effects of purifying selection and ectopic recombination removing ERVs from the genome. In addition to providing these biological insights, our study demonstrates the power of exploiting multiple scales and localization with FDA. These powerful techniques are expected to be applicable to many other genomic investigations

  2. Mapping Full-Length Porcine Endogenous Retroviruses in a Large White Pig

    PubMed Central

    Herring, C.; Quinn, G.; Bower, R.; Parsons, N.; Logan, N. A.; Brawley, A.; Elsome, K.; Whittam, A.; Fernandez-Suarez, X. M.; Cunningham, D.; Onions, D.; Langford, G.; Scobie, L.

    2001-01-01

    Xenotransplantation may bridge the widening gap between the shortage of donor organs and the increasing number of patients waiting for transplantation. However, a major safety issue is the potential cross-species transmission of porcine endogenous retroviruses (PERV). This problem could be resolved if it is possible to produce pigs that do not contain replication-competent copies of this virus. In order to determine the feasibility of this, we have determined the number of potentially replication-competent full-length PERV proviruses and obtained data on their integration sites within the porcine genome. We have screened genomic DNA libraries from a Large White pig for potentially intact proviruses. We identified six unique PERV B proviruses that were apparently intact in all three genes, while the majority of isolated proviruses were defective in one or more genes. No intact PERV A proviruses were found in this pig, despite the identification of multiple defective A proviruses. Genotyping of 30 unrelated pigs for these unique proviruses showed a heterogeneous distribution. Two proviruses were uncommon, present in 7 of 30 and 3 of 30 pigs, while three were each present in 24 of 30 pigs, and one was present in 30 of 30 animals examined. Our data indicate that few PERV proviruses in Large White pigs are capable of productive infection and suggest that many could be removed by selective breeding. Further studies are required to determine if all potentially functional proviruses could be removed by breeding or whether gene knockout techniques will be required to remove the residuum. PMID:11711616

  3. Identification of Exogenous Forms of Human-Tropic Porcine Endogenous Retrovirus in Miniature Swine

    PubMed Central

    Wood, James C.; Quinn, Gary; Suling, Kristen M.; Oldmixon, Beth A.; Van Tine, Brian A.; Cina, Robert; Arn, Scott; Huang, Christine A.; Scobie, Linda; Onions, David E.; Sachs, David H.; Schuurman, Henk-Jan; Fishman, Jay A.; Patience, Clive

    2004-01-01

    The replication of porcine endogenous retrovirus subgroup A (PERV-A) and PERV-B in certain human cell lines indicates that PERV may pose an infectious risk in clinical xenotransplantation. We have previously reported that human-tropic PERVs isolated from infected human cells following cocultivation with miniature swine peripheral blood mononuclear cells (PBMC) are recombinants of PERV-A with PERV-C. Here, we report that these recombinants are exogenous viruses in miniature swine; i.e., they are not present in the germ line DNA. These viruses were invariably present in miniature swine that transmitted PERV to human cells and were also identified in some miniature swine that lacked this ability. These data, together with the demonstration of the absence of both replication-competent PERV-A and recombinant PERV-A/C loci in the genome of miniature swine (L. Scobie, S. Taylor, J. C. Wood, K. M. Suling, G. Quinn, C. Patience, H.-J. Schuurman, and D. E. Onions, J. Virol. 78:2502-2509, 2004), indicate that exogenous PERV is the principal source of human-tropic virus in these animals. Interestingly, strong expression of PERV-C in PBMC correlated with an ability of the PBMC to transmit PERV-A/C recombinants in vitro, indicating that PERV-C may be an important factor affecting the production of human-tropic PERV. In light of these observations, the safety of clinical xenotransplantation from miniature swine will be most enhanced by the utilization of source animals that do not transmit PERV to either human or porcine cells. Such animals were identified within the miniature swine herd and may further enhance the safety of clinical xenotransplantation. PMID:14963150

  4. Porcine Endogenous Retrovirus Infects but Does Not Replicate in Nonhuman Primate Primary Cells and Cell Lines

    PubMed Central

    Ritzhaupt, Armin; van der Laan, Luc J. W.; Salomon, Daniel R.; Wilson, Carolyn A.

    2002-01-01

    Porcine endogenous retroviruses (PERV) can infect human cell lines in vitro; hence, there is a presumed risk of viral exposure to a recipient when pig cells are transplanted into humans (xenotransplantation). Nonhuman primates (NHP) are considered a potential permissive animal model to study the risk of in vivo infection of PERV after xenotransplantation. We set out to determine whether PERV can infect and replicate in NHP primary cells or established cell lines from African green monkey, rhesus macaque, and baboon. We confirm that the NHP cell lines under investigation were infected with PERV as measured by detection of viral DNA and RNA by PCR and reverse transcription (RT)-PCR, respectively, indicating that a functional receptor must be present on the cell surface. However, the load of detectable viral DNA in infected NHP cells declined over time, and the cells never had detectable reverse transcriptase activity. Utilizing quantitative real-time TaqMan PCR we found detectable levels of unintegrated DNA intermediates, but the levels were approximately 100-fold lower compared to HEK 293 cells infected with PERV. Virions released from infected NHP cells could productively infect naïve human cell lines, HEK 293 and HeLa, as shown by RT-PCR and RT assay. However, naïve NHP cells remained negative in RT-PCR and RT assay after exposure to virions from infected NHP cells. Together our data demonstrate that NHP cells are not permissive to productive replication by PERV, presumably due to inefficient cell entry and replication. In light of these observations, the appropriateness of NHP as suitable animal models to study PERV infection in vivo needs to be reevaluated. PMID:12388691

  5. The HERV-K Human Endogenous Retrovirus Envelope Protein Antagonizes Tetherin Antiviral Activity

    PubMed Central

    Lemaître, Cécile; Harper, Francis; Pierron, Gérard

    2014-01-01

    ABSTRACT Endogenous retroviruses are the remnants of past retroviral infections that are scattered within mammalian genomes. In humans, most of these elements are old degenerate sequences that have lost their coding properties. The HERV-K(HML2) family is an exception: it recently amplified in the human genome and corresponds to the most active proviruses, with some intact open reading frames and the potential to encode viral particles. Here, using a reconstructed consensus element, we show that HERV-K(HML2) proviruses are able to inhibit Tetherin, a cellular restriction factor that is active against most enveloped viruses and acts by keeping the viral particles attached to the cell surface. More precisely, we identify the Envelope protein (Env) as the viral effector active against Tetherin. Through immunoprecipitation experiments, we show that the recognition of Tetherin is mediated by the surface subunit of Env. Similar to Ebola glycoprotein, HERV-K(HML2) Env does not mediate Tetherin degradation or cell surface removal; therefore, it uses a yet-undescribed mechanism to inactivate Tetherin. We also assessed all natural complete alleles of endogenous HERV-K(HML2) Env described to date for their ability to inhibit Tetherin and found that two of them (out of six) can block Tetherin restriction. However, due to their recent amplification, HERV-K(HML2) elements are extremely polymorphic in the human population, and it is likely that individuals will not all possess the same anti-Tetherin potential. Because of Tetherin's role as a restriction factor capable of inducing innate immune responses, this could have functional consequences for individual responses to infection. IMPORTANCE Tetherin, a cellular protein initially characterized for its role against HIV-1, has been proven to counteract numerous enveloped viruses. It blocks the release of viral particles from producer cells, keeping them tethered to the cell surface. Several viruses have developed strategies to

  6. Integration of the BALB/c ecotropic provirus into the colony-stimulating factor-1 growth factor locus in a myc retrovirus-induced murine monocyte tumor.

    PubMed

    Baumbach, W R; Colston, E M; Cole, M D

    1988-09-01

    The development of tumors is thought to be a multistage process that requires an unknown number of genetic or epigenetic changes in a single cell. We previously described a murine monocyte tumor which was induced by a helper-free c-myc retrovirus and which also contained a DNA rearrangement at the colony-stimulating factor-1 (CSF-1) locus. The CSF-1 gene rearrangement gave rise to high levels of growth factor production and autocrine growth, implicating this secondary event in tumorigenesis. This CSF-1 gene rearrangement was found to be the result of integration of the BALB/c ecotropic retrovirus. Restriction enzyme mapping and DNA sequence analysis demonstrated that the novel provirus is identical to the BALB/c endogenous ecotropic provirus, indicating that infection was probably not due to the creation of a recombinant virus in vivo. The proviral integration site was mapped 3 kilobases 5' of the CSF-1 promoter and in an opposite transcriptional orientation, indicating that activation of CSF-1 expression was the result of the presence of the retroviral enhancer element. PMID:3261346

  7. Gene profiling of the erythro- and megakaryoblastic leukaemias induced by the Graffi murine retrovirus

    PubMed Central

    2010-01-01

    Background Acute erythro- and megakaryoblastic leukaemias are associated with very poor prognoses and the mechanism of blastic transformation is insufficiently elucidated. The murine Graffi leukaemia retrovirus induces erythro- and megakaryoblastic leukaemias when inoculated into NFS mice and represents a good model to study these leukaemias. Methods To expand our understanding of genes specific to these leukaemias, we compared gene expression profiles, measured by microarray and RT-PCR, of all leukaemia types induced by this virus. Results The transcriptome level changes, present between the different leukaemias, led to the identification of specific cancerous signatures. We reported numerous genes that may be potential oncogenes, may have a function related to erythropoiesis or megakaryopoiesis or have a poorly elucidated physiological role. The expression pattern of these genes has been further tested by RT-PCR in different samples, in a Friend erythroleukaemic model and in human leukaemic cell lines. We also screened the megakaryoblastic leukaemias for viral integrations and identified genes targeted by these integrations and potentially implicated in the onset of the disease. Conclusions Taken as a whole, the data obtained from this global gene profiling experiment have provided a detailed characterization of Graffi virus induced erythro- and megakaryoblastic leukaemias with many genes reported specific to the transcriptome of these leukaemias for the first time. PMID:20102610

  8. A Linkage Map of Endogenous Murine Leukemia Proviruses

    PubMed Central

    Frankel, W. N.; Stoye, J. P.; Taylor, B. A.; Coffin, J. M.

    1990-01-01

    Thirty endogenous proviruses belonging to the modified polytropic (Mpmv) class of murine leukemia virus (MLV) were identified by proviral-cellular DNA junction fragment segregation in several sets of recombinant inbred mice. Twenty-six Mpmv loci were mapped to chromosomal regions by matching proviral strain distribution patterns to those of previously assigned genes. Like other endogenous nonecotropic MLVs, Mpmv loci were present on several chromosomes in all strains examined. We pooled recombinant inbred strain linkage data from 110 MLV loci and selected marker genes in order to construct a chromosomal linkage map. Every mouse chromosome was found to harbor at least one proviral insertion, and several regions contained multiple integrations. However, the overall distribution of the 110 mapped proviruses did not deviate significantly from a random distribution. Because of their polymorphism in inbred strains of mice, and the ability to score as many as 57 proviruses per strain using only three hybridization probes, the nonecotropic MLVs mapped in common strains of mice offer a significant advantage over older methods (e.g., biochemical or individual restriction fragment polymorphisms) as genetic markers. These endogenous insertion elements should also be useful for assessing strain purity, and for studying the relatedness of common and not-so-common inbred strains. PMID:2155154

  9. Sgp3 and Sgp4 Control Expression of Distinct and Restricted Sets of Xenotropic Retroviruses Encoding Serum gp70 Implicated in Murine Lupus Nephritis

    PubMed Central

    Kihara, Maso; Leroy, Valérie; Baudino, Lucie; Evans, Leonard H.; Izui, Shozo

    2011-01-01

    The envelope glycoprotein gp70 of endogenous retroviruses implicated in murine lupus nephritis is secreted by hepatocytes and its expression is controlled by Sgp3 (serum gp70 production 3) and Sgp4 loci derived from lupusprone mice. Among three different endogenous retroviruses (ecotropic, xenotropic and polytropic), xenotropic viruses are considered to be the major source of serum gp70. Although the abundance of xenotropic viral gp70 RNA in livers was up-regulated by the presence of these two Sgp loci, it has not yet been clear whether Sgp3 and Sgp4 regulate the expression of a fraction or multiple xenotropic viruses present in mouse genome. To address this question, we determined the genetic origin of xenotropic viral sequences expressed in wildtype and two different Sgp congenic C57BL/6 mice. Among 14 xenotropic proviruses present in the C57BL/6 genome, only two proviruses (Xmv10 and Xmv14) were actively transcribed in wild-type C57BL/6 mice. In contrast, Sgp3 enhanced the transcription of Xmv10 and induced the transcription of three additional xenotropic viruses (Xmv15, Xmv17 and Xmv18), while Sgp4 induced the expression of a different xenotropic virus (Xmv13). Notably, stimulation of TLR7 in Sgp3 congenic C57BL/6 mice led to a highly enhanced expression of potentially replication-competent Xmv18. These results indicated that Sgp3 and Sgp4 independently regulated the transcription of distinct and restricted sets of xenotropic viruses in trans, thereby promoting the production of nephritogenic gp70 autoantigens. Furthermore, the induced expression of potentially replication-competent xenotropic viruses by Sgp3 may contribute to the development of autoimmune responses against gp70 through the activation of TLR7. PMID:21982749

  10. OVEX1, a novel chicken endogenous retrovirus with sex-specific and left-right asymmetrical expression in gonads

    PubMed Central

    Carré-Eusèbe, Danièle; Coudouel, Noëlline; Magre, Solange

    2009-01-01

    Background In chickens, as in most birds, female gonad morphogenesis is asymmetrical. Gonads appear first rather similarly, but only the left one undergoes full differentiation and gives rise to a functional ovary. The right gonad, in which the cortex does not develop, remains restricted to the medulla and finally regresses. Opportunity was taken of this left-right asymmetry to perform a suppression subtractive hybridization screening to select for transcripts preferentially expressed in the developing left ovary as compared to the right one, and thus identify genes that are potentially involved in the process of ovarian differentiation. Results One of these transcripts, named Ovex1 according to its expression profile, corresponds to an endogenous retrovirus that has not been previously characterized. It is transcribed as full-length and singly spliced mRNAs and contains three uninterrupted open reading frames coding potentially for proteins with homology to Gag and Pro-Pol retroviral polyproteins and a third protein showing only a weak similarity with Env glycoproteins. Ovex1 is severely degenerated; it is devoid of typical long terminal repeats and displays some evidence of recombination. An orthologous Ovex1 locus was identified in the genome of zebra finch, a member of a different bird order, and similar sequences were detected in turkey, guinea fowl, and duck DNA. The relationship between these sequences follows the bird phylogeny, suggesting vertical transmission of the endogenous retrovirus for more than 100 million years. Ovex1 is transcribed in chicken gonads with a sex-dependent and left-right asymmetrical pattern. It is first expressed in the cortex of the left indifferent gonads of both sexes. Expression is transient in the left testis and absent in the right one. In developing ovaries, Ovex1 transcription increases sharply in the left cortex and is weakly detected in the medulla. After folliculogenesis, Ovex1-expressing cells constitute the follicular

  11. Ethanol consumption and early murine retrovirus infection influence liver, heart, and muscle levels of iron, zinc, and copper in C57BL/6 mice.

    PubMed

    Shahbazian, L M; Wood, S; Watson, R R

    1994-08-01

    The relative and combined roles of ethanol and murine acquired immunodeficiency syndrome (MAIDS) on the mineral status (Fe, Zn, and Cu) of liver (storage site), heart, muscle (nutrient mobile sites) were investigated. C57BL/6 mice were randomly assigned to four groups: (a) uninfected mice fed isocaloric, adequate nutrient diet (NRC), (b) uninfected mice fed the NRC diet with 25% of energy derived from ethanol, (c) LP-BM5 retrovirus-infected mice fed the isocaloric NRC diet, and (d) retrovirus-infected mice fed the NRC diet with 25% of its energy derived from ethanol. The levels of Cu and Zn levels in the liver did not significantly change as a result of ethanol consumption. However hepatic Zn concentration was increased significantly in retrovirus-infected mice. This may be correlated to the increase in their liver weight. Ethanol administration significantly increased Fe concentration in the liver, yet significantly decreased concentration of Cu in the heart. Retrovirus infection alone, which had not proceeded to murine AIDS, resulted in a significant increase in heart Cu and Zn concentration as compared with uninfected mice. Retrovirus infection in C57BL/6 mice significantly increased Fe and Zn level/g of muscle. Early retrovirus infection alters tissue micronutrient levels, and may thus contribute to immunological changes. PMID:7978111

  12. Surveys of endogenous retroviruses (ERVs) in the freshwater crocodile (Crocodylus johnstoni) suggest that ERVs in Crocodylus spp. vary between species.

    PubMed

    Chong, Amanda Y; Kjeldsen, Shannon R; Gongora, Jaime

    2015-04-01

    Endogenous retroviruses (ERVs) are one of many families of transposable elements present in vertebrate genomes. We have examined the ERV complement of the freshwater crocodile (Crocodylus johnstoni) in order to investigate the diversity of ERVs present and possibility of ERV or retroviral activity in a diseased individual of this species. Amplification and sequencing of the highly conserved retroviral pro-pol domains revealed high levels of sequence variation in these ERVs. Phylogenetic analyses of these ERVs and those previously identified in other crocodilian species suggest that although many crocodilians share the same ERV lineages, the relative numbers of retroelement insertions from each of these lineages may vary greatly between species. The data generated in this study provide evidence for the presence of a unique and varied complement of ERVs in crocodilians. This study has also demonstrated the presence of species-specific evolution in ancient retroviral infections. PMID:25653017

  13. Expression of the Human Endogenous Retrovirus HTDV/HERV-K Is Enhanced by Cellular Transcription Factor YY1

    PubMed Central

    Knössl, Michael; Löwer, Roswitha; Löwer, Johannes

    1999-01-01

    The human endogenous retrovirus HTDV/HERV-K, which resides in moderate copy numbers in the human genome, is expressed in a cell-type-specific manner, predominantly in teratocarcinoma cells. We have analyzed the regulatory potential of the 5′ enhancer of the HERV-K long terminal repeat. Protein extracts of HERV-K-expressing teratocarcinoma cell lines (GH and Tera2) and nonexpressing HeLa and HepG2 cells form different protein complexes on the enhancer sequence as detected by electrophoretic mobility shift assays (EMSA). Using competition EMSAs, DNase I footprinting, and supershift experiments, we localized the binding site of these complexes to a 20-bp sequence within the enhancer and showed that the transcription factor YY1 is one component of the HERV-K enhancer complex. Replacement of the YY1 binding site with unrelated sequences reduced expression of the luciferase gene as a reporter in transient-transfection assays. PMID:9882329

  14. Dynamic Evolution of Endogenous Retrovirus-Derived Genes Expressed in Bovine Conceptuses during the Period of Placentation

    PubMed Central

    Nakagawa, So; Bai, Hanako; Sakurai, Toshihiro; Nakaya, Yuki; Konno, Toshihiro; Miyazawa, Takayuki; Gojobori, Takashi; Imakawa, Kazuhiko

    2013-01-01

    In evolution of mammals, some of essential genes for placental development are known to be of retroviral origin, as syncytin-1 derived from an envelope (env) gene of an endogenous retrovirus (ERV) aids in the cell fusion of placenta in humans. Although the placenta serves the same function in all placental mammals, env-derived genes responsible for trophoblast cell fusion and maternal immune tolerance differ among species and remain largely unidentified in the bovine species. To examine env-derived genes playing a role in the bovine placental development comprehensively, we determined the transcriptomic profiles of bovine conceptuses during three crucial windows of implantation periods using a high-throughput sequencer. The sequence reads were mapped into the bovine genome, in which ERV candidates were annotated using RetroTector© (7,624 and 1,542 for ERV-derived and env-derived genes, respectively). The mapped reads showed that approximately 18% (284 genes) of env-derived genes in the genome were expressed during placenta formation, and approximately 4% (63 genes) were detected for all days examined. We verified three env-derived genes that are expressed in trophoblast cells by polymerase chain reaction. Out of these three, the sequence of env-derived gene with the longest open reading frame (named BERV-P env) was found to show high expression levels in trophoblast cell lines and to be similar to those of syncytin-Car1 genes found in dogs and cats, despite their disparate origins. These results suggest that placentation depends on various retrovirus-derived genes that could have replaced endogenous predecessors during evolution. PMID:23335121

  15. The distribution of endogenous chicken retrovirus sequences in the DNA of galliform birds does not coincide with avian phylogenetic relationships.

    PubMed

    Frisby, D P; Weiss, R A; Roussel, M; Stehelin, D

    1979-07-01

    The chicken is a domesticated form of Red Jungle-fowl (Gallus gallus), which belongs to the Pheasant family (Phasianidae) within the order Galliformes. Domestic chickens carry the genome of the endogenous retrovirus RAV-O as DNA sequences integrated into host chromosomes transmitted through the germ line. We have examined the presence and distribution of RAV-O-related sequences in the DNA of Red Junglefowl and other closely related species of Junglefowl, as well as more distantly related Pheasants and Quail. DNA sequences homologous to RAV-O were analyzed by molecular hybridization in liquid and after electrophoresis of restriction endonuclease fragments. The presence of RAV-O-related sequences in avian DNA does not correlate with phylogenetic relationships. Under stringent conditions of hybridization in liquid, DNA sequences homologous to RAV-O cDNA were detected at high levels (greater than 80% homology( only in the genomes of the domestic chicken and its phylogenetic ancestor, the Red Junglefowl (Gallus gallus). The DNA of two other species of Gallus (G. sonnerati, Sonnerat's Junglefowl and G. varius, Green Junglefowl), of Ring-necked Pheasant and of Japanese Quail contained sequences with less than 10% homology to RAV-O cDNA. Under conditions permitting mismatching, however, Ring-necked Pheasant DNA hybridized up to 50% of the RAV-O cDNA, and Quail DNA 24%, whereas the extent of hybridization to Sonnerat's and Green Junglefowl DNA was not markedly increased. Analysis of restriction enzyme digests revealed several distinct fragments of DNA hybridizing to chick retrovirus cDNA in both Red Junglefowl and domestic chicken, and multiple fragments in DNA from two species of Phasianus. No fragments with sequences related to chicken retroviruses were found, however, in digests of DNA prepared from Sonnerat's, Ceylonese and Green Junglefowl, from two other Pheasant genera (Chrysolophus and Lophura), or from one Quail genus (Coturnix). Thus the DNA of three Junglefowl

  16. Proviral amplification of the Gypsy endogenous retrovirus of Drosophila melanogaster involves env-independent invasion of the female germline.

    PubMed

    Chalvet, F; Teysset, L; Terzian, C; Prud'homme, N; Santamaria, P; Bucheton, A; Pélisson, A

    1999-05-01

    Gypsy is an infectious endogenous retrovirus of Drosophila melanogaster. The gypsy proviruses replicate very efficiently in the genome of the progeny of females homozygous for permissive alleles of the flamenco gene. This replicative transposition is correlated with derepression of gypsy expression, specifically in the somatic cells of the ovaries of the permissive mothers. The determinism of this amplification was studied further by making chimeric mothers containing different permissive/restrictive and somatic/germinal lineages. We show here that the derepression of active proviruses in the permissive soma is necessary and sufficient to induce proviral insertions in the progeny, even if the F1 flies derive from restrictive germ cells devoid of active proviruses. Therefore, gypsy endogenous multiplication results from the transfer of some gypsy-encoded genetic material from the soma towards the germen of the mother and its subsequent insertion into the chromosomes of the progeny. This transfer, however, is not likely to result from retroviral infection of the germline. Indeed, we also show here that the insertion of a tagged gypsy element, mutant for the env gene, occurs at high frequency, independently of the production of gypsy Env proteins by any transcomplementing helper. The possible role of the env gene for horizontal transfer to new hosts is discussed. PMID:10228177

  17. Apparent effect of rabbit endogenous lentivirus type K acquisition on retrovirus restriction by lagomorph Trim5αs

    PubMed Central

    Yap, Melvyn W.; Stoye, Jonathan P.

    2013-01-01

    To test the hypothesis that rabbit endogenous lentivirus type K (RELIK) could play a role in shaping the evolution of TRIM5α, the susceptibility of viruses containing the RELIK capsid (CA) to TRIM5 restriction was evaluated. RELIK CA-containing viruses were susceptible to the TRIM5αs from Old World monkeys but were unaffected by most ape or New World monkey factors. TRIM5αs from various lagomorph species were also isolated and tested for anti-retroviral activity. The TRIM5αs from both cottontail rabbit and pika restrict a range of retroviruses, including HIV-1, HIV-2, FIV, EIAV and N-MLV. TRIM5αs from the European and cottontail rabbit, which have previously been found to contain RELIK, also restricted RELIK CA-containing viruses, whereas a weaker restriction was observed with chimeric TRIM5α containing the B30.2 domain from the pika, which lacks RELIK. Taken together, these results could suggest that the pika had not been exposed to exogenous RELIK and that endogenized RELIK might exert a selective pressure on lagomorph TRIM5α. PMID:23938750

  18. The activation of human endogenous retrovirus K (HERV-K) is implicated in melanoma cell malignant transformation

    SciTech Connect

    Serafino, A. Balestrieri, E.; Pierimarchi, P.; Matteucci, C.; Moroni, G.; Oricchio, E.; Rasi, G.; Mastino, A.; Spadafora, C.; Garaci, E.; Vallebona, P. Sinibaldi

    2009-03-10

    Melanoma development is a multi-step process arising from a series of genetic and epigenetic events. Although the sequential stages involved in progression from melanocytes to malignant melanoma are clearly defined, our current understanding of the mechanisms leading to melanoma onset is still incomplete. Growing evidence show that the activation of endogenous retroviral sequences might be involved in transformation of melanocytes as well as in the increased ability of melanoma cells to escape immune surveillance. Here we show that human melanoma cells in vitro undergo a transition from adherent to a more malignant, non-adherent phenotype when exposed to stress conditions. Melanoma-derived non-adherent cells are characterized by an increased proliferative potential and a decreased expression of both HLA class I molecules and Melan-A/MART-1 antigen, similarly to highly malignant cells. These phenotypic and functional modifications are accompanied by the activation of human endogenous retrovirus K expression (HERV-K) and massive production of viral-like particles. Down-regulation of HERV-K expression by RNA interference prevents the transition from the adherent to the non-adherent growth phenotype in low serum. These results implicate HERV-K in at least some critical steps of melanoma progression.

  19. The role of molecular mimicry and other factors in the association of Human Endogenous Retroviruses and autoimmunity.

    PubMed

    Trela, Malgorzata; Nelson, Paul N; Rylance, Paul B

    2016-01-01

    Human Endogenous Retroviruses (HERVs) have been implicated in autoimmune and other diseases. Molecular mimicry has been postulated as a potential mechanism of autoimmunity. Exogenous viruses have also been reported to be associated with the same diseases, as have genetic and environmental factors. If molecular mimicry were to be shown to be an initiating mechanism of some autoimmune diseases, then therapeutic options of blocking antibodies and peptides might be of benefit in halting diseases at the outset. Bioinformatic and molecular modelling techniques have been employed to investigate molecular mimicry and the evidence for the association of HERVs and autoimmunity is reviewed. The most convincing evidence for molecular mimicry is in rheumatoid arthritis, where HERV K-10 shares amino acid sequences with IgG1Fc, a target for rheumatoid factor. Systemic lupus erythematosus is an example of a condition associated with several autoantibodies, and several endogenous and exogenous viruses have been reported to be associated with the disease. The lack of a clear link between one virus and this condition, and the spectrum of clinical manifestations, suggests that genetic, environmental and the inflammatory response to a virus or viruses might also be major factors in the pathogenesis of lupus and other autoimmune conditions. Where there are strong associations between a virus and an autoimmune condition, such as in hepatitis C and cryoglobulinaemia, the use of bioinformatics and molecular modelling can also be utilized to help to understand the role of molecular mimicry in how HERVs might trigger disease. PMID:26818264

  20. Strong purifying selection in endogenous retroviruses in the saltwater crocodile (Crocodylus porosus) in the Northern Territory of Australia

    PubMed Central

    2012-01-01

    Background Endogenous retroviruses (ERVs) are remnants of exogenous retroviruses that have integrated into the nuclear DNA of a germ-line cell. Here we present the results of a survey into the ERV complement of Crocodylus porosus, the saltwater crocodile, representing 45 individuals from 17 sampling locations in the Northern Territory of Australia. These retroelements were compared with published ERVs from other species of Crocodylia (Crocodilians; alligators, caimans, gharials and crocodiles) as well as representatives from other vertebrates. This study represents one of the first in-depth studies of ERVs within a single reptilian species shedding light on the diversity of ERVs and proliferation mechanisms in crocodilians. Results Analyses of the retroviral pro-pol gene region have corroborated the presence of two major clades of ERVs in C. porosus and revealed 18 potentially functional fragments out of the 227 recovered that encode intact pro-pol ORFs. Interestingly, we have identified some patterns of diversification among those ERVs as well as a novel sequence that suggests the presence of an additional retroviral genus in C. porosus. In addition, considerable diversity but low genetic divergence within one of the C. porosus ERV lineages was identified. Conclusions We propose that the ERV complement of C. porosus has come about through a combination of recent infections and replication of ancestral ERVs. Strong purifying selection acting on these clades suggests that this activity is recent or still occurring in the genome of this species. The discovery of potentially functional elements is an interesting development that warrants further investigation. PMID:23217152

  1. Human Endogenous Retrovirus HERV-K14 Families: Status, Variants, Evolution, and Mobilization of Other Cellular Sequences†

    PubMed Central

    Flockerzi, Aline; Burkhardt, Stefan; Schempp, Werner; Meese, Eckart; Mayer, Jens

    2005-01-01

    The human genome harbors many distinct families of human endogenous retroviruses (HERVs) that stem from exogenous retroviruses that infected the germ line millions of years ago. Many HERV families remain to be investigated. We report in the present study the detailed characterization of the HERV-K14I and HERV-K14CI families as they are represented in the human genome. Most of the 68 HERV-K14I and 23 HERV-K14CI proviruses are severely mutated, frequently displaying uniform deletions of retroviral genes and long terminal repeats (LTRs). Both HERV families entered the germ line ∼39 million years ago, as evidenced by homologous sequences in hominoids and Old World primates and calculation of evolutionary ages based on a molecular clock. Proviruses of both families were formed during a brief period. A majority of HERV-K14CI proviruses on the Y chromosome mimic a higher evolutionary age, showing that LTR-LTR divergence data can indicate false ages. Fully translatable consensus sequences encoding major retroviral proteins were generated. Most HERV-K14I loci lack an env gene and are structurally reminiscent of LTR retrotransposons. A minority of HERV-K14I variants display an env gene. HERV-K14I proviruses are associated with three distinct LTR families, while HERV-K14CI is associated with a single LTR family. Hybrid proviruses consisting of HERV-K14I and HERV-W sequences that appear to have produced provirus progeny in the genome were detected. Several HERV-K14I proviruses harbor TRPC6 mRNA portions, exemplifying mobilization of cellular transcripts by HERVs. Our analysis contributes essential information on two more HERV families and on the biology of HERV sequences in general. PMID:15709013

  2. Human Endogenous Retrovirus Type K (HERV-K) Particles Package and Transmit HERV-K–Related Sequences

    PubMed Central

    Contreras-Galindo, Rafael; Kaplan, Mark H.; Dube, Derek; Gonzalez-Hernandez, Marta J.; Chan, Susana; Meng, Fan; Dai, Manhong; Omenn, Gilbert S.; Gitlin, Scott D.

    2015-01-01

    ABSTRACT Human endogenous retroviruses (HERV) make up 8% of the human genome. While the youngest of these retroviruses, HERV-K(HML-2), termed HK2, is able to code for all viral proteins and produce virus-like particles, it is not known if these virus particles package and transmit HK2-related sequences. Here, we analyzed the capacity of HK2 for packaging and transmitting HK2 sequences. We created an HK2 probe, termed Bogota, which can be packaged into HK2 viruses, and transfected it into cells that make HK2 particles. Supernatants of the transfected cells, which contained HK2 viral particles, then were added to target cells, and the transmissibility of the HK2 Bogota reporter was tracked by G418 resistance. Our studies revealed that contemporary HK2 virions produced by some teratocarcinoma and breast cancer cell lines, as well as by peripheral blood lymphocytes from lymphoma patients, can package HK2 Bogota probes, and these viruses transmitted these probes to other cells. After transmission, HK2 Bogota transcripts undergo reverse transcription, a step impaired by antiretroviral agents or by introduction of mutations into the probe sequences required for reverse transcription. HK2 viruses were more efficiently transmitted in the presence of HK2 Rec or HIV-1 Tat and Vif. Transmitted Bogota probes formed episomes but did not integrate into the cellular genome. Resistance to integration might explain the relatively low number of HK2 insertions that were acquired during the last 25 million years of evolution. Whether transient transmission of modern HK2 sequences, which encode two putative oncoproteins, can lead to disease remains to be studied. IMPORTANCE Retroviruses invaded the genome of human ancestors over the course of millions of years, yet these viruses generally have been inactivated during evolution, with only remnants of these infectious sequences remaining in the human genome. One of these viruses, termed HK2, still is capable of producing virus particles

  3. Identification of two distinct structural regions in a human porcine endogenous retrovirus receptor, HuPAR2, contributing to function for viral entry

    PubMed Central

    Marcucci, Katherine T; Argaw, Takele; Wilson, Carolyn A; Salomon, Daniel R

    2009-01-01

    Background Of the three subclasses of Porcine Endogenous Retrovirus (PERV), PERV-A is able to infect human cells via one of two receptors, HuPAR1 or HuPAR2. Characterizing the structure-function relationships of the two HuPAR receptors in PERV-A binding and entry is important in understanding receptor-mediated gammaretroviral entry and contributes to evaluating the risk of zoonosis in xenotransplantation. Results Chimeras of the non-permissive murine PAR and the permissive HuPAR2, which scanned the entire molecule, revealed that the first 135 amino acids of HuPAR2 are critical for PERV-A entry. Within this critical region, eighteen single residue differences exist. Site-directed mutagenesis used to map single residues confirmed the previously identified L109 as a binding and infectivity determinant. In addition, we identified seven residues contributing to the efficiency of PERV-A entry without affecting envelope binding, located in multiple predicted structural motifs (intracellular, extracellular and transmembrane). We also show that expression of HuPAR2 in a non-permissive cell line results in an average 11-fold higher infectivity titer for PERV-A compared to equal expression of HuPAR1, although PERV-A envelope binding is similar. Chimeras between HuPAR-1 and -2 revealed that the region spanning amino acids 152–285 is responsible for the increase of HuPAR2. Fine mapping of this region revealed that the increased receptor function required the full sequence rather than one or more specific residues. Conclusion HuPAR2 has two distinct structural regions. In one region, a single residue determines binding; however, in both regions, multiple residues influence receptor function for PERV-A entry. PMID:19144196

  4. Endogenous New World primate retrovirus: interspecies antigenic determinants shared with the major structural protein of type-D RNA viruses of Old World monkeys.

    PubMed Central

    Hino, S; Tronick, S R; Heberling, R L; Kalter, S S; Hellman, A; Aaronson, S A

    1977-01-01

    A reverse transcriptase-containing virus has recently been isolated from a squirrel monkey (Saimiri sciureus). Molecular hybridization studies demonstrate that the squirrel monkey retrovirus (SMRV) is endogenous to this New World primate, yet lacks detectable nucleotide sequence homology with cellular DNAs of representative Old World primates or with the genomes of previously isolated Old World primate retroviruses. The 35,000-dalton major structural protein (p35) of SMRV was purified and shown to possess antigenic determinants distinct from those of known retroviruses. While SMRV was found to lack antigenic determinants broadly shared among mammalian type-C viruses, immunologic crossreactivity was demonstrated between SMRV p35 and the major structural protein (p26) of Mason-Pfizer monkey virus, a prototype type-D retrovirus of Old World monkeys. These findings support the concept that SMRV and Mason-Pfizer monkey virus are evolutionarily related, and raise the possibility that a progenitor of type-D retroviruses became genetically associated with primates at a very early time in their evolution. PMID:74833

  5. Identification and Characterization of an Exogenous Retrovirus from Atlantic Salmon Swim Bladder Sarcomas

    PubMed Central

    Paul, Thomas A.; Quackenbush, Sandra L.; Sutton, Claudia; Casey, Rufina N.; Bowser, Paul R.; Casey, James W.

    2006-01-01

    A novel piscine retrovirus has been identified in association with an outbreak of leiomyosarcoma in the swim bladders of Atlantic salmon. The complete nucleotide sequence of the Atlantic salmon swim bladder sarcoma virus (SSSV) provirus is 10.9 kb in length and shares a structure and transcriptional profile similar to those of murine leukemia virus-like simple retroviruses. SSSV appears unique to simple retroviruses by not harboring sequences in the Atlantic salmon genome. Additionally, SSSV differs from other retroviruses in potentially utilizing a methionine tRNA primer binding site. SSSV-associated tumors contain high proviral copy numbers (greater than 30 per cell) and a polyclonal integration pattern. Phylogenetic analysis based on reverse transcriptase places SSSV with zebrafish endogenous retrovirus (ZFERV) between the Gammaretrovirus and Epsilonretrovirus genera. Large regions of continuous homology between SSSV and ZFERV Gag, Pol, and Env suggest that these viruses represent a new group of related piscine retroviruses. PMID:16501103

  6. Chemiluminescent Detection for Estimating Relative Copy Numbers of Porcine Endogenous Retrovirus Proviruses from Chinese Minipigs Based on Magnetic Nanoparticles.

    PubMed

    Yang, Haowen; Liu, Ming; Zhou, Bingcong; Deng, Yan; He, Nongyue; Jiang, Hesheng; Guo, Yafen; Lan, Ganqiu; Jiang, Qinyang; Yang, Xiurong; Li, Zhiyang

    2016-06-01

    Chinese Bama minipigs could be potential donors for the supply of xenografts because they are genetically stable, highly inbred, and inexpensive. However, porcine endogenous retrovirus (PERV) is commonly integrated in pig genomes and could cause a cross-species infection by xenotransplantation. For screening out the pigs with low copy numbers of PERV proviruses, we have developed a novel semiquantitative analysis approach based on magnetic nanoparticles (MNPs) and chemiluminescence (CL) for estimating relative copy numbers (RCNs) of PERV proviruses in Chinese Bama minipigs. The CL intensities of PERV proviruses and the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were respectively determined with this method, and the RCNs of PERV proviruses were calculated by the equation: RCN of PERV provirus = CL intensity of PERV provirus/CL intensity of GAPDH. The results showed that PERVs were integrated in the genomes of Bama minipigs at different copy numbers, and the copy numbers of PERV-C subtype were greatly low. Two Bama minipigs with low copy numbers of PERV proviruses were detected out and could be considered as xenograft donor candidates. Although only semiquantitation can be achieved, this approach has potential for screening out safe and suitable pig donors for xenotransplantation. PMID:27427744

  7. Identification of Active Loci of a Human Endogenous Retrovirus in Neurons of Patients with Amyotrophic Lateral Sclerosis

    PubMed Central

    Douville, Renée; Liu, Jiankai; Rothstein, Jeffrey; Nath, Avindra

    2010-01-01

    Background Amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of motor neurons, of unknown etiology. Previous studies showed reverse transcriptase in serum of ALS patients at levels comparable to HIV-infected patients; however, the source and significance of the retroviral elements is uncertain. Methods Expression of a human endogenous retrovirus (HERV-K), was determined in autopsy brain tissue of patients with ALS and compared to control populations, by real time polymerase chain reaction followed by sequencing of the amplified genes and confirmed by immunostaining. Results HERV-K pol transcripts were increased in patients with ALS compared to those with chronic systemic illness, but could not be detected in Parkinson’s disease or in the accidental death controls. Sequencing revealed several actively transcribed loci in the HML-2 and 3 subfamilies of HERV-K, with a specific pattern of expression including intact open reading frames and the transcription of a unique locus in ALS. The frequency of intact pol transcripts was highest in the motor cortex and the reverse transcriptase protein was localized to cortical neurons of ALS patients. HERV-K expression strongly correlated with TDP-43, a multi-functional protein known to be dysregulated in ALS. Interpretation We have identified a specific pattern of HERV-K expression in ALS, which may potentially define the pathophysiology of ALS. Targeting of activated genome-encoded retroviral elements may open new prospects for the treatment of ALS. PMID:21280084

  8. Evidence for a piwi-dependent RNA silencing of the gypsy endogenous retrovirus by the Drosophila melanogaster flamenco gene.

    PubMed

    Sarot, Emeline; Payen-Groschêne, Geneviève; Bucheton, Alain; Pélisson, Alain

    2004-03-01

    In Drosophila melanogaster, the endogenous retrovirus gypsy is repressed by the functional alleles (restrictive) of an as-yet-uncloned heterochromatic gene called flamenco. Using gypsy-lacZ transcriptional fusions, we show here that this repression takes place not only in the follicle cells of restrictive ovaries, as was previously observed, but also in restrictive larval female gonads. Analyses of the role of gypsy cis-regulatory sequences in the control of gypsy expression are also presented. They rule out the hypothesis that gypsy would contain a single binding region for a putative Flamenco repressor. Indeed, the ovarian expression of a chimeric yp3-lacZ construct was shown to become sensitive to the Flamenco regulation when any of three different 5'-UTR gypsy sequences (ranging from 59 to 647 nucleotides) was incorporated into the heterologous yp3-lacZ transcript. The piwi mutation, which is known to affect RNA-mediated homology-dependent transgene silencing, was also shown to impede the repression of gypsy in restrictive female gonads. Finally, a RNA-silencing model is also supported by the finding in ovaries of short RNAs (25-27 nucleotides long) homologous to sequences from within the gypsy 5'-UTR. PMID:15082550

  9. ‘There and back again’: revisiting the pathophysiological roles of human endogenous retroviruses in the post-genomic era

    PubMed Central

    Magiorkinis, Gkikas; Belshaw, Robert; Katzourakis, Aris

    2013-01-01

    Almost 8% of the human genome comprises endogenous retroviruses (ERVs). While they have been shown to cause specific pathologies in animals, such as cancer, their association with disease in humans remains controversial. The limited evidence is partly due to the physical and bioethical restrictions surrounding the study of transposons in humans, coupled with the major experimental and bioinformatics challenges surrounding the association of ERVs with disease in general. Two biotechnological landmarks of the past decade provide us with unprecedented research artillery: (i) the ultra-fine sequencing of the human genome and (ii) the emergence of high-throughput sequencing technologies. Here, we critically assemble research about potential pathologies of ERVs in humans. We argue that the time is right to revisit the long-standing questions of human ERV pathogenesis within a robust and carefully structured framework that makes full use of genomic sequence data. We also pose two thought-provoking research questions on potential pathophysiological roles of ERVs with respect to immune escape and regulation. PMID:23938753

  10. Activation of endogenous human stem cell-associated retroviruses (SCARs) and therapy-resistant phenotypes of malignant tumors.

    PubMed

    Glinsky, Gennadi V

    2016-07-01

    Recent reports revealed consistent activation of specific endogenous retroviral elements in human preimplantation embryos and embryonic stem cells. Activity of stem cell associated retroviruses (SCARs) has been implicated in seeding thousands of human-specific regulatory sequences in the hESC genome. Activation of specific SCARs has been demonstrated in patients diagnosed with multiple types of cancer, autoimmune diseases, and neurodegenerative disorders, and appears associated with clinically lethal therapy resistant death-from-cancer phenotypes in a sub-set of cancer patients diagnosed with different types of malignant tumors. A hallmark feature of human-specific SCAR integration sites is deletions of ancestral DNA. Analysis of human-specific genetic loci of SCARs' stemness networks in tumor samples of TCGA cohorts representing 29 cancer types suggests that this approach may facilitate identification of pan-cancer genomic signatures of clinically-lethal disease defined by the presence of somatic non-silent mutations, gene-level copy number changes, and transcripts and proteins' expression of SCAR-regulated host genes. Present analyses indicate that multiple lines of strong circumstantial evidence support the hypothesis that activation of SCARs' networks may play an important role in cancer progression and metastasis, perhaps contributing to the emergence of clinically-lethal therapy-resistant death-from-cancer phenotypes. PMID:27084523

  11. Autoantibodies to human endogenous retrovirus-K are frequently detected in health and disease and react with multiple epitopes

    PubMed Central

    HERVÉ, C A; LUGLI, E B; BRAND, A; GRIFFITHS, D J; VENABLES, P J W

    2002-01-01

    A number of studies have found increased levels of antibodies to human endogenous retroviruses (HERVs) in autoimmune rheumatic diseases. It is not clear whether this immune response is driven by the HERV itself or by cross-reactions with an exogenous virus or an autoantigen. To address this question, we examined the antibody response to the Env protein of two closely related members of the HERV-K family, HERV-K10 and IDDMK1,222. By immunoblotting of recombinant proteins, antibodies were found in 32–47% of 84 sera from patients with autoimmune rheumatic disease, and 29% of 35 normal controls. Epitope mapping with overlapping 15mers identified multiple reactive peptides on both antigens, with one (GKTCPKEIPKGSKNT) containing immunodominant epitope(s). By ELISA, the median titre of antibody to this peptide was significantly increased in 39 patients with SLE compared to 39 healthy controls and 86 patients with other rheumatic diseases (P < 0·003). We have shown that there is a high frequency of IgG antibodies to HERV-K env sequences in human sera, both in health and autoimmune rheumatic disease, and that the response is to multiple epitopes. This supports the hypothesis that the autoimmune response to HERV-K is antigen-driven and may be an early stage in the chain of events that leads to tolerance breakdown to other autoantigens. PMID:11982593

  12. Refrex-1, a Soluble Restriction Factor against Feline Endogenous and Exogenous Retroviruses

    PubMed Central

    Ito, Jumpei; Watanabe, Shinya; Hiratsuka, Takahiro; Kuse, Kyohei; Odahara, Yuka; Ochi, Haruyo; Kawamura, Maki

    2013-01-01

    The host defense against viral infection is acquired during the coevolution or symbiosis of the host and pathogen. Several cellular factors that restrict retroviral infection have been identified in the hosts. Feline leukemia virus (FeLV) is a gammaretrovirus that is classified into several receptor interference groups, including a novel FeLV-subgroup D (FeLV-D) that we recently identified. FeLV-D is generated by transduction of the env gene of feline endogenous gammaretrovirus of the domestic cat (ERV-DCs) into FeLV. Some ERV-DCs are replication competent viruses which are present and hereditary in cats. We report here the determination of new viral receptor interference groups and the discovery of a soluble antiretroviral factor, termed Refrex-1. Detailed analysis of FeLV-D strains and ERV-DCs showed two receptor interference groups that are distinct from other FeLV subgroups, and Refrex-1 specifically inhibited one of them. Refrex-1 is characterized as a truncated envelope protein of ERV-DC and includes the N-terminal region of surface unit, which is a putative receptor-binding domain, but lacks the transmembrane region. Refrex-1 is efficiently secreted from the cells and appears to cause receptor interference extracellularly. Two variants of Refrex-1 encoded by provirus loci, ERV-DC7 and DC16, are expressed in a broad range of feline tissues. The host retains Refrex-1 as an antiretroviral factor, which may potentially prevent reemergence of the ERVs and the emergence of novel ERV-related viruses in cats. Refrex-1 may have been acquired during endogenization of ERV-DCs and may play an important role in retroviral restriction and antiviral defense in cats. PMID:23966402

  13. Endogenous retrovirus EAV-HP linked to blue egg phenotype in Mapuche fowl.

    PubMed

    Wragg, David; Mwacharo, Joram M; Alcalde, José A; Wang, Chen; Han, Jian-Lin; Gongora, Jaime; Gourichon, David; Tixier-Boichard, Michèle; Hanotte, Olivier

    2013-01-01

    Oocyan or blue/green eggshell colour is an autosomal dominant trait found in native chickens (Mapuche fowl) of Chile and in some of their descendants in European and North American modern breeds. We report here the identification of an endogenous avian retroviral (EAV-HP) insertion in oocyan Mapuche fowl and European breeds. Sequencing data reveals 100% retroviral identity between the Mapuche and European insertions. Quantitative real-time PCR analysis of European oocyan chicken indicates over-expression of the SLCO1B3 gene (P<0.05) in the shell gland and oviduct. Predicted transcription factor binding sites in the long terminal repeats (LTR) indicate AhR/Ar, a modulator of oestrogen, as a possible promoter/enhancer leading to reproductive tissue-specific over-expression of the SLCO1B3 gene. Analysis of all jungle fowl species Gallus sp. supports the retroviral insertion to be a post-domestication event, while identical LTR sequences within domestic chickens are in agreement with a recent de novo mutation. PMID:23990950

  14. Endogenous Retrovirus EAV-HP Linked to Blue Egg Phenotype in Mapuche Fowl

    PubMed Central

    Alcalde, José A.; Wang, Chen; Han, Jian-Lin; Gongora, Jaime; Gourichon, David; Tixier-Boichard, Michèle; Hanotte, Olivier

    2013-01-01

    Oocyan or blue/green eggshell colour is an autosomal dominant trait found in native chickens (Mapuche fowl) of Chile and in some of their descendants in European and North American modern breeds. We report here the identification of an endogenous avian retroviral (EAV-HP) insertion in oocyan Mapuche fowl and European breeds. Sequencing data reveals 100% retroviral identity between the Mapuche and European insertions. Quantitative real-time PCR analysis of European oocyan chicken indicates over-expression of the SLCO1B3 gene (P<0.05) in the shell gland and oviduct. Predicted transcription factor binding sites in the long terminal repeats (LTR) indicate AhR/Ar, a modulator of oestrogen, as a possible promoter/enhancer leading to reproductive tissue-specific over-expression of the SLCO1B3 gene. Analysis of all jungle fowl species Gallus sp. supports the retroviral insertion to be a post-domestication event, while identical LTR sequences within domestic chickens are in agreement with a recent de novo mutation. PMID:23990950

  15. Expression of HERV-Fc1, a Human Endogenous Retrovirus, Is Increased in Patients with Active Multiple Sclerosis

    PubMed Central

    Brudek, Tomasz; Nissen, Kari Konstantin; Christensen, Tove; Møller-Larsen, Anné; Petersen, Thor; Nexø, Bjørn Andersen

    2012-01-01

    Multiple sclerosis (MS) is considered to be an autoimmune disease with an unknown cause and with immune system dysregulation. Among environmental factors, viruses are most often connected with the etiology of MS. Human endogenous retroviruses (HERVs) constitute 5 to 8% of human genomic DNA and have been detected as transcripts and proteins in the central nervous system (CNS) and peripheral blood, frequently in the context of neuroinflammation. HERV-Fc1, which belongs to the HERV-H/F family, has received our attention largely because of the genetic association with MS. We studied the expression of a capsid (Gag) protein of HERV-H/F origin by flow cytometry in peripheral blood mononuclear cells (PBMCs) from healthy controls and from MS patients with nonactive or active disease. There was a significant increase in HERV-H/F Gag expression in CD4+ (P < 0.001) and CD8+ (P < 0.001) T lymphocytes and in monocytes (P = 0.0356) in PBMCs from MS patients with active disease. Furthermore, we have undertaken the first rigorous SYBR green-based absolute quantitative PCR (Q-PCR) evaluation approach to quantify extracellular HERV-Fc1 RNA viral loads in plasma from MS patients and healthy controls. We found a 4-fold increase in extracellular HERV-Fc1 RNA titers in patients with active MS compared with healthy controls (P < 0.001). These findings strengthen the link between HERV-Fc1 and the pathology of MS. The cause and biological consequences of these differential expression levels will be the subject of further investigation. HERV-Fc1 biology could be a compelling area for understanding the pathology of MS and possibly other autoimmune disorders. PMID:22278236

  16. Further Evidence that Human Endogenous Retrovirus K102 is a Replication Competent Foamy Virus that may Antagonize HIV-1 Replication

    PubMed Central

    Laderoute, Marian P.; Larocque, Louise J.; Giulivi, Antonio; Diaz-Mitoma, Francisco

    2015-01-01

    Objective: The goals of the research were to determine if a foamy effect on macrophages was due to human endogenous retrovirus K102 (HERV-K102) replication, and to further address its potential significance in HIV-1 infection. Methods: An RT-PCR HERV-K HML-2 pol method was used to screen the unknown HERV, and isolated bands were sent for sequencing. Confirmation of RNA expression was performed by a real time quantitative PCR (qPCR) pol ddCt method. Rabbit antibodies to Env peptides were used to assess expression by immunohistology and processing of Env by western blots. A qPCR pol ddCt method to ascertain genomic copy number was performed on genomic DNA isolated from plasma comparing HIV-1 exposed seronegative (HESN) commercial sex workers (CSW) to normal controls and contrasted with HIV-1 patients. Results: HERV-K102 expression, particle production and replication were associated with foamy macrophage generation in the cultures of cord blood mononuclear cells under permissive conditions. A five-fold increased HERV-K102 pol genomic copy number was found in the HESN cohort over normal which was not found in HIV-1 positive patients (p=0.0005). Conclusions: This work extends the evidence that HERV-K102 has foamy virus attributes, is replication competent, and is capable of high replication rate in vivo and in vitro. This may be the first characterization of a replication-competent, foamy-like virus of humans. High particle production inferred by increased integration in the HESN cohort over HIV-1 patients raises the issue of the clinical importance of HERV-K102 particle production as an early protective innate immune response against HIV-1 replication. PMID:26793281

  17. Absence of Replication-Competent Human-Tropic Porcine Endogenous Retroviruses in the Germ Line DNA of Inbred Miniature Swine

    PubMed Central

    Scobie, Linda; Taylor, Samantha; Wood, James C.; Suling, Kristen M.; Quinn, Gary; Meikle, Sharon; Patience, Clive; Schuurman, Henk-Jan; Onions, David E.

    2004-01-01

    The potential transmission of porcine endogenous retroviruses (PERVs) has raised concern in the development of porcine xenotransplantation products. Our previous studies have resulted in the identification of animals within a research herd of inbred miniature swine that lack the capacity to transmit PERV to human cells in vitro. In contrast, other animals were capable of PERV transmission. The PERVs that were transmitted to human cells are recombinants between PERV-A and PERV-C in the post-VRA region of the envelope (B. A. Oldmixon, J. C. Wood, T. A. Ericsson, C. A. Wilson, M. E. White-Scharf, G. Andersson, J. L. Greenstein, H. J. Schuurman, and C. Patience, J. Virol. 76:3045-3048, 2002); these viruses we term PERV-A/C. This observation prompted us to determine whether these human-tropic replication-competent (HTRC) PERV-A/C recombinants were present in the genomic DNA of these miniature swine. Genomic DNA libraries were generated from one miniature swine that transmitted HTRC PERV as well as from one miniature swine that did not transmit HTRC PERV. HTRC PERV-A/C proviruses were not identified in the germ line DNAs of these pigs by using genomic mapping. Similarly, although PERV-A loci were identified in both libraries that possessed long env open reading frames, the Env proteins encoded by these loci were nonfunctional according to pseudotype assays. In the absence of a germ line source for HTRC PERV, further studies are warranted to assess the mechanisms by which HTRC PERV can be generated. Once identified, it may prove possible to generate animals with further reduced potential to produce HTRC PERV. PMID:14963152

  18. Establishment and Characterization of Molecular Clones of Porcine Endogenous Retroviruses Replicating on Human Cells

    PubMed Central

    Czauderna, Frank; Fischer, Nicole; Boller, Klaus; Kurth, Reinhard; Tönjes, Ralf R.

    2000-01-01

    The use of pig xenografts is being considered to alleviate the shortage of allogeneic organs for transplantation. In addition to the problems overcoming immunological and physiological barriers, the existence of numerous porcine microorganisms poses the risk of initiating a xenozoonosis. Recently, different classes of type C porcine endogenous retoviruses (PERV) which are infectious for human cells in vitro have been partially described. We therefore examined whether completely intact proviruses exist that produce infectious and replication-competent virions. Several proviral PERV sequences were cloned and characterized. One molecular PERV class B clone, PERV-B(43), generated infectious particles after transfection into human 293 cells. A second clone, PERV-B(33), which was highly homologous to PERV-B(43), showed a G-to-A mutation in the first start codon (Met to Ile) of the env gene, preventing this provirus from replicating. However, a genetic recombinant, PERV-B(33)/ATG, carrying a restored env start codon, became infectious and could be serially passaged on 293 cells similar to virus clone PERV-B(43). PERV protein expression was detected 24 to 48 h posttransfection (p.t.) using cross-reacting antiserum, and reverse transcriptase activity was found at 12 to 14 days p.t. The transcriptional start and stop sites as well as the splice donor and splice acceptor sites of PERV mRNA were mapped, yielding a subgenomic env transcript of 3.1 kb. PERV-B(33) and PERV-B(43) differ in the number of copies of a 39-bp segment in the U3 region of the long terminal repeat. Strategies to identify and to specifically suppress or eliminate those proviruses from the pig genome might help in the production of PERV-free animals. PMID:10756014

  19. Development of retrovirus vectors useful for expressing genes in cultured murine embryonal cells and hematopoietic cells in vivo.

    PubMed Central

    Guild, B C; Finer, M H; Housman, D E; Mulligan, R C

    1988-01-01

    A series of retrovirus vectors were constructed in which cellular promoter elements derived from the chicken beta-actin and human histone H4 genes were introduced within the proviral transcriptional unit of Moloney murine leukemia virus in order to promote expression of inserted sequences. Each of these vectors gave rise to high titer of virus capable of transferring the expected proviral structure to cells. Inclusion of normal 5' splice sequences or a portion of viral gag sequences in these constructions resulted in significant increases in virus titer. Each construction was transcriptionally active in NIH 3T3 cells and in undifferentiated F9 cells. One of the vectors, HSG-neo, which contained the human histone H4 promoter, was shown to be transcriptionally active in hematopoietic cells derived from long-term reconstituted bone marrow transplant recipients engrafted with transduced stem cells. These vectors should be of general use for obtaining efficient gene expression in embryonal and hematopoietic cells. Images PMID:3418785

  20. Macroevolution of complex retroviruses.

    PubMed

    Katzourakis, Aris; Gifford, Robert J; Tristem, Michael; Gilbert, M Thomas P; Pybus, Oliver G

    2009-09-18

    Retroviruses can leave a "fossil record" in their hosts' genomes in the form of endogenous retroviruses. Foamy viruses, complex retroviruses that infect mammals, have been notably absent from this record. We have found an endogenous foamy virus within the genomes of sloths and show that foamy viruses were infecting mammals more than 100 million years ago and codiverged with their hosts across an entire geological era. Our analysis highlights the role of evolutionary constraint in maintaining viral genome structure and indicates that accessory genes and mammalian mechanisms of innate immunity are the products of macroevolutionary conflict played out over a geological time scale. PMID:19762636

  1. Sequence heterogeneity of murine acquired immunodeficiency syndrome virus: the role of endogenous virus.

    PubMed

    Gayama, S; Vaupel, B A; Kanagawa, O

    1995-05-01

    A defective murine leukemia virus is the causative agent of murine acquired immunodeficiency syndrome (MAIDS). We have cloned cDNAs from both virus infected and non-infected cells using the PCR methods with primers corresponding to the franking sequence of the unique p12 gag gene. Sequence analysis of these cDNA clones revealed: (i) the presence of endogenous virus related to MAIDS virus in C57BL/6 mice, (ii) B cell lineage specific expression of endogenous virus and (iii) extensive heterogeneity of MAIDS virus recovered from virus infected cells due to the recombination of the related viruses (defective pathogenic virus, ecotropic virus and endogenous virus). These findings suggest that the creation of virus variants in infected cells may play an important role in virus pathogenesis and escape from immune attack during the development of MAIDS. PMID:7547712

  2. Murine Stem Cell-Based Retrovirus Production for Marking Primary Mouse Mammary Cells for Metastasis Studies.

    PubMed

    Beverly, Levi J; Podsypanina, Katrina

    2016-02-01

    Since the introduction of retroviral vector technology, permanent genetic marking of cells has considerably contributed to the understanding of different physiological and disease processes in vivo. Recent marking strategies aim to elucidate the contribution of cells on the clonal level, and the advent of fluorescent proteins has opened new avenues for the in vivo analysis of gene-marked cells. Gene-modified cells are easily identifiable (e.g., via the introduced fluorescent protein) within whole organ structures, allowing one to measure the contribution of transduced cells to malignant outgrowth. In our laboratory, we use the tetracycline-inducible system to study oncogene cooperation in metastatic progression. We use bicistronic retroviruses expressing the tetracycline transactivator (tTA) and the candidate gene (MIT-gene) or the tTA alone (MIT-Rx) to infect primary mammary cells from mice harboring tetracycline-inducible transgenes. This allows for constitutive expression of the candidate gene and tTA-dependent expression of the inducible oncogene. We also use MIG-based vectors, which allow for constitutive expression of the candidate gene and a green fluorescent protein. Here we describe how to produce retroviral particles carrying both MIT- and MIG-based vectors. Because of the fragility of the retroviral envelope, we do not attempt to concentrate the virus, and we directly use packaging cell media to infect primary epithelial cells (either normal or tumor). Infected cells can be transplanted into recipient mice to investigate metastatic colonization. PMID:26832680

  3. Structure, distribution, and expression of an ancient murine endogenous retroviruslike DNA family.

    PubMed Central

    Obata, M M; Khan, A S

    1988-01-01

    An endogenous retroviruslike DNA, B-26, was cloned from a BALB/c mouse embryo gene library by using a generalized murine leukemia virus DNA probe. Southern blot hybridization and nucleotide sequence analyses indicated that B-26 DNA might be a novel member of the GLN DNA family (A. Itin and E. Keshet, J. Virol. 59:301-307, 1986) which contains murine leukemia virus-related pol and env sequences. Northern analysis indicated that B-26-related RNAs of 8.4 and 3.0 kilobases were transcribed in thymus, spleen, brain, and liver tissues of 6-week-old BALB/c mice. Images PMID:3172346

  4. Involvement of microglial CD40 in murine retrovirus-induced peripheral neuropathy.

    PubMed

    Cao, Ling; Butler, M Brady

    2013-08-15

    B6 mice infected with LP-BM5 develop severe immunodeficiency (termed murine acquired immunodeficiency syndrome (MAIDS)) and peripheral neuropathy. To determine whether microglial CD40 is involved in LP-BM5-induced peripheral neuropathy, B6-CD40 knockout (KO) mice and B6-CD40 KO mice adoptively transferred either total leukocytes or B cells were examined for behavioral sensitivity, tissue viral loads, cytokine responses, and the development of MAIDS. All three CD40 KO groups developed MAIDS, the severity of which was correlated with peripheral cytokine responses. CD40 KO mice displayed significantly reduced mechanical hypersensitivity post-infection compared to wild-type mice regardless of cell transfer. These findings support microglial CD40 involvement in LP-BM5-induced peripheral neuropathy. PMID:23726765

  5. Custom human endogenous retroviruses dedicated microarray identifies self-induced HERV-W family elements reactivated in testicular cancer upon methylation control

    PubMed Central

    Gimenez, Juliette; Montgiraud, Cécile; Pichon, Jean-Philippe; Bonnaud, Bertrand; Arsac, Maud; Ruel, Karine; Bouton, Olivier; Mallet, François

    2010-01-01

    Endogenous retroviruses (ERVs) are an inherited part of the eukaryotic genomes, and represent ∼400 000 loci in the human genome. Human endogenous retroviruses (HERVs) can be divided into distinct families, composed of phylogenetically related but structurally heterogeneous elements. The majority of HERVs are silent in most physiological contexts, whereas a significant expression is observed in pathological contexts, such as cancers. Owing to their repetitive nature, few of the active HERV elements have been accurately identified. In addition, there are no criteria defining the active promoters among HERV long-terminal repeats (LTRs). Hence, it is difficult to understand the HERV (de)regulation mechanisms and their implication on the physiopathology of the host. We developed a microarray to specifically detect the LTR-containing transcripts from the HERV-H, HERV-E, HERV-W and HERV-K(HML-2) families. HERV transcriptome was analyzed in the placenta and seven normal/tumoral match-pair samples. We identified six HERV-W loci overexpressed in testicular cancer, including a usually placenta-restricted transcript of ERVWE1. For each locus, specific overexpression was confirmed by quantitative RT-PCR, and comparison of the activity of U3 versus U5 regions suggested a U3-promoted transcription coupled with 5′R initiation. The analysis of DNA from tumoral versus normal tissue revealed that hypomethylation of U3 promoters in tumors is a prerequisite for their activation. PMID:20053729

  6. Human Endogenous Retrovirus Family HERV-K(HML-5): Status, Evolution, and Reconstruction of an Ancient Betaretrovirus in the Human Genome†

    PubMed Central

    Lavie, Laurence; Medstrand, Patrik; Schempp, Werner; Meese, Eckart; Mayer, Jens

    2004-01-01

    The human genome harbors numerous distinct families of so-called human endogenous retroviruses (HERV) which are remnants of exogenous retroviruses that entered the germ line millions of years ago. We describe here the hitherto little-characterized betaretrovirus HERV-K(HML-5) family (named HERVK22 in Repbase) in greater detail. Out of 139 proviruses, only a few loci represent full-length proviruses, and many lack gag protease and/or env gene regions. We generated a consensus sequence from multiple alignment of 62 HML-5 loci that displays open reading frames for the four major retroviral proteins. Four HML-5 long terminal repeat (LTR) subfamilies were identified that are associated with monophyletic proviral bodies, implying different evolution of HML-5 LTRs and genes. Sequence analysis indicated that the proviruses formed approximately 55 million years ago. Accordingly, HML-5 proviral sequences were detected in Old World and New World primates but not in prosimians. No recent activity is associated with this HERV family. We also conclude that the HML-5 consensus sequence primer binding site is identical to methionine tRNA. Therefore, the family should be designated HERV-M. Our study provides important insights into the structure and evolution of the oldest betaretrovirus in the primate genome known to date. PMID:15280487

  7. Modulation of ecotropic murine retroviruses by N-linked glycosylation of the cell surface receptor/amino acid transporter.

    PubMed Central

    Wang, H; Klamo, E; Kuhmann, S E; Kozak, S L; Kavanaugh, M P; Kabat, D

    1996-01-01

    The cell surface receptor for ecotropic host-range (infection limited to mice or rats) murine leukemia viruses (MuLVs) is the widely expressed system y+ transporter for cationic amino acids (CAT-1). Like other retroviruses, ecotropic MuLV infection eliminates virus-binding sites from cell surfaces and results in complete interference to superinfection. Surprisingly, infection causes only partial (ca 40 to 60%) loss of mouse CAT-1 transporter activity. The NIH/Swiss mouse CAT-1 (mCAT-1) contains 622 amino acids with 14 hydrophobic potential membrane-spanning sequences, and it is known that the third extracellular loop from the amino terminus is required for virus binding. Although loop 3 is hypervariable in different species and mouse strains, consistent with its proposed role in virus-host coevolution, loop 3 sequences of both susceptible and resistant species contain consensus sites for N-linked glycosylation. Both of the consensus sites in loop 3 of mCAT-1 are known to be glycosylated and to contain oligosaccharides with diverse sizes (J. W. Kim and J. M. Cunningham, J. Biol. Chem. 268:16316-16320, 1993). We confirmed by several lines of evidence that N-linked glycosylation occludes a potentially functional virus-binding site in the CAT-1 protein of hamsters, thus contributing to resistance of that species. To study the role of receptor glycosylation in animals susceptible to infection, we eliminated loop 3 glycosylation sites by mutagenesis of an mCAT-1 cDNA clone, and we expressed wild-type and mutant receptors in mink fibroblasts and Xenopus oocytes. These receptors had indistinguishable transport properties, as determined by kinetic and voltage-jump electrophysiological studies of arginine uptake in oocytes and by analyses Of L-[3H]arginine uptake in mink cells. Bindings of ecotropic envelope glycoprotein gp7O to the accessible receptor sites on surfaces of mink cells expressing wild-type or mutant mCAT-1 were not significantly different in kinetics or in

  8. A soluble envelope protein of endogenous retrovirus (FeLIX) present in serum of domestic cats mediates infection of a pathogenic variant of feline leukemia virus.

    PubMed

    Sakaguchi, Shoichi; Shojima, Takayuki; Fukui, Daisuke; Miyazawa, Takayuki

    2015-03-01

    T-lymphotropic feline leukemia virus (FeLV-T), a highly pathogenic variant of FeLV, induces severe immunosuppression in cats. FeLV-T is fusion defective because in its PHQ motif, a gammaretroviral consensus motif in the N terminus of an envelope protein, histidine is replaced with aspartate. Infection by FeLV-T requires FeLIX, a truncated envelope protein encoded by an endogenous FeLV, for transactivation of infectivity and Pit1 for binding FeLIX. Although Pit1 is present in most tissues in cats, the expression of FeLIX is limited to certain cells in lymphoid organs. Therefore, the host cell range of FeLV-T was thought to be restricted to cells expressing FeLIX. However, because FeLIX is a soluble factor and is expressed constitutively in lymphoid organs, we presumed it to be present in blood and evaluated its activities in sera of various mammalian species using a pseudotype assay. We demonstrated that cat serum has FeLIX activity at a functional level, suggesting that FeLIX is present in the blood and that FeLV-T may be able to infect cells expressing Pit1 regardless of the expression of FeLIX in vivo. In addition, FeLIX activities in sera were detected only in domestic cats and not in other feline species tested. To our knowledge, this is the first report to prove that a large amount of truncated envelope protein of endogenous retrovirus is circulating in the blood to facilitate the infection of a pathogenic exogenous retrovirus. PMID:25395593

  9. Study of Full-Length Porcine Endogenous Retrovirus Genomes with Envelope Gene Polymorphism in a Specific-Pathogen-Free Large White Swine Herd

    PubMed Central

    Bösch, Steffi; Arnauld, Claire; Jestin, André

    2000-01-01

    Specific-pathogen-free (SPF) swine appear to be the most appropriate candidate for pig to human xenotransplantation. Still, the risk of endogenous retrovirus transmission represents a major obstacle, since two human-tropic porcine endogenous retroviruses (PERVs) had been characterized in vitro (P. Le Tissier, J. P. Stoye, Y. Takeuchi, C. Patience, and R. A. Weiss, Nature 389:681–682, 1997). Here we addressed the question of PERV distribution in a French Large White SPF pig herd in vivo. First, PCR screening for previously described PERV envelope genes envA, envB, and envC (D. E. Akiyoshi, M. Denaro, H. Zhu, J. L. Greenstein, P. Banerjee, and J. A. Fishman, J. Virol. 72:4503–4507, 1998; Le Tissier et al., op. cit.). demonstrated ubiquity of envA and envB sequences, whereas envC genes were absent in some animals. On this basis, selective out-breeding of pigs of remote origin might be a means to reduce proviral load in organ donors. Second, we investigated PERV genome carriage in envC negative swine. Eleven distinct full-length PERV transcripts were isolated. The sequence of the complete envelope open reading frame was determined. The deduced amino acid sequences revealed the existence of four clones with functional and five clones with defective PERV PK-15 A- and B-like envelope sequences. The occurrence of easily detectable levels of PERV variants in different pig tissues in vivo heightens the need to assess PERV transmission in xenotransplantation animal models. PMID:10954559

  10. Endogenous Murine BST-2/Tetherin Is Not a Major Restriction Factor of Influenza A Virus Infection

    PubMed Central

    Job, Emma R.; Moffat, Jessica M.; Wakim, Linda M.; Gonelli, Christopher A.; Purcell, Damien F. J.; Brooks, Andrew G.; Villadangos, Jose A.; Reading, Patrick C.; Mintern, Justine D.

    2015-01-01

    BST-2 (tetherin, CD317, HM1.24) restricts virus growth by tethering enveloped viruses to the cell surface. The role of BST-2 during influenza A virus infection (IAV) is controversial. Here, we assessed the capacity of endogenous BST-2 to restrict IAV in primary murine cells. IAV infection increased BST-2 surface expression by primary macrophages, but not alveolar epithelial cells (AEC). BST-2-deficient AEC and macrophages displayed no difference in susceptibility to IAV infection relative to wild type cells. Furthermore, BST-2 played little role in infectious IAV release from either AEC or macrophages. To examine BST-2 during IAV infection in vivo, we infected BST-2-deficient mice. No difference in weight loss or in viral loads in the lungs and/or nasal tissues were detected between BST-2-deficient and wild type animals. This study rules out a major role for endogenous BST-2 in modulating IAV in the mouse model of infection. PMID:26566124

  11. Characterization of lymphoid tumors induced by a recombinant murine retrovirus carrying the avian v-myc oncogene. Identification of novel (B-lymphoid) tumors in the thymus.

    PubMed

    Brightman, B K; Chandy, K G; Spencer, R H; Gupta, S; Pattengale, P K; Fan, H

    1988-10-15

    Lymphoid tumors induced by a recombinant murine retrovirus carrying the v-myc oncogene of avian MC29 virus were characterized. The Moloney murine leukemia virus myc oncogene (M-MuLV (myc], carried by an amphotropic MuLV helper, induced tumors in NIH Swiss and NFS/N mice after a relatively long latency (8 to 24 wk). Tumor masses appeared in the thymus, spleen, and lymph nodes. Flow cytometry of the tumor cells indicated that approximately 50% were positive for Thy 1.2. Most of these tumors also expressed one or more other cell surface markers of thymocytes and mature T cells (CD4, CD8). Southern blot hybridization revealed genomic rearrangements for the TCR beta genes. The TCR beta analysis suggested that the M-MuLV(myc)-induced Thy 1.2+ tumors were derived from somewhat less mature cells than tumors induced by M-MuLV, which is a classical non-acute retrovirus lacking an oncogene. The remainder of the M-MuLV(myc)-induced tumors were Thy 1.2-, but they were positive for Ly-5 (B220) and also for MAC-2. The Thy 1.2- tumors were characteristically located in the thymus. However, they were negative for TCR beta gene rearrangements. Some, but not all, of the Thy 1.2- tumors contained rearrangements for Ig genes. Additionally, they typically expressed mRNA specific for B but not for T cells. Thus, these thymic tumors had characteristics of the B cell lineage. Tumor transplantation experiments demonstrated that the Thy 1.2- tumor cells could reestablish in the thymus and spleen of irradiated hosts, and low level expression of the Thy 1 molecule was observed in the thymus but not the spleen on the first passage. After serial passage, one Thy 1- tumor altered its cell surface phenotype to Thy 1low B220-. PMID:2902139

  12. Noncanonical MicroRNAs and Endogenous siRNAs in Lytic Infection of Murine Gammaherpesvirus

    PubMed Central

    Xia, Jing; Zhang, Weixiong

    2012-01-01

    MicroRNA (miRNA) and endogenous small interfering RNA (endo-siRNA) are two essential classes of small noncoding RNAs (sncRNAs) in eukaryotes. The class of miRNA is diverse and there exist noncanonical miRNAs that bypass the canonical miRNA biogenesis pathway. In order to identify noncanonical miRNAs and endo-siRNAs responding to virus infection and study their potential function, we sequenced small-RNA species from cells lytically infected with murine gammaherpesvirus 68 (MHV68). In addition to three novel canonical miRNAs in mouse, two antisense miRNAs in virus and 25 novel noncanonical miRNAs, including miRNAs derived from transfer RNAs, small nucleolar RNAs and introns, in the host were identified. These noncanonical miRNAs exhibited features distinct from that of canonical miRNAs in lengths of hairpins, base pairings and first nucleotide preference. Many of the novel miRNAs are conserved in mammals. Besides several known murine endo-siRNAs detected by the sequencing profiling, a novel locus in the mouse genome was identified to produce endo-siRNAs. This novel endo-siRNA locus is comprised of two tandem inverted B4 short interspersed nuclear elements (SINEs). Unexpectedly, the SINE-derived endo-siRNAs were found in a variety of sequencing data and virus-infected cells. Moreover, a murine miRNA was up-regulated more than 35 fold in infected than in mock-treated cells. The putative targets of the viral and the up-regulated murine miRNAs were potentially involved in processes of gene transcription and protein phosphorylation, and localized to membranes, suggesting their potential role in manipulating the host basal immune system during lytic infection. Our results extended the number of noncanonical miRNAs in mammals and shed new light on their potential functions of lytic infection of MHV68. PMID:23110115

  13. Transcriptional and functional studies of Human Endogenous Retrovirus envelope EnvP(b) and EnvV genes in human trophoblasts

    SciTech Connect

    Vargas, Amandine Thiery, Maxime Lafond, Julie Barbeau, Benoit

    2012-03-30

    HERV (Human Endogenous Retrovirus)-encoded envelope proteins are implicated in the development of the placenta. Indeed, Syncytin-1 and -2 play a crucial role in the fusion of human trophoblasts, a key step in placentation. Other studies have identified two other HERV env proteins, namely EnvP(b) and EnvV, both expressed in the placenta. In this study, we have fully characterized both env transcripts and their expression pattern and have assessed their implication in trophoblast fusion. Through RACE analyses, standard spliced transcripts were detected, while EnvV transcripts demonstrated alternative splicing at its 3 Prime end. Promoter activity and expression of both genes were induced in forskolin-stimulated BeWo cells and in primary trophoblasts. Although we have confirmed the fusogenic activity of EnvP(b), overexpression or silencing experiments revealed no impact of this protein on trophoblast fusion. Our results demonstrate that both env genes are expressed in human trophoblasts but are not required for syncytialization.

  14. Endogenous nitric oxide limits cytokine-induced damage of murine lung epithelial cells.

    PubMed

    Burke-Gaffney, A; Hellewell, P G

    1997-04-01

    This study investigated whether endogenous nitric oxide (NO) limits cytokine-induced damage to the murine lung epithelial cell line LA-4. NO production was assessed as nitrite using the Griess reaction, and cell damage was assessed using ethidium homodimer-1. Cytotoxicity was first detected after a 24-h incubation with a combination of tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma (cytomix). Nitrite production increased to 78.0 +/- 0.5 nmol/10(6) cells at 24 h. Coincubation of LA-4 with cytomix and NO synthase inhibitors, aminoguanidine (3-1,000 microM) and N(G)-monomethyl-L-arginine (10-1,000 microM), but not N(G)-monomethyl-D-arginine, or a soluble guanylate cyclase inhibitor, 1H-[1,2,4] oxadiazole [4,3-a] quinoxalin-1-one, reduced cytomix-induced nitrite production and increased cytotoxicity up to twofold (24 h). Removal of L-arginine from the medium increased damage; reintroduction of 1,000 microM L-arginine, but not D-arginine, reversed this. In aminoguanidine-treated cells, replacement of NO with an NO donor, S-nitrosoglutathione (30 microM), reversed, in part, the cell damage observed in aminoguanidine/cytomix-treated cells. These results suggest that endogenous NO limits cytokine-induced lung epithelial damage. PMID:9142945

  15. The “complex” RNA post-transcriptional element of a “simple” retrovirus

    PubMed Central

    Purzycka, Katarzyna J; Pilkington, Guy R; Felber, Barbara K; Le Grice, Stuart F J

    2015-01-01

    Replication of retroviruses and transposition of endogenous retroelements exploits a unique mechanism of post-transcriptional regulation as a means of exporting their incompletely-spliced mRNAs (which serve as both the genomic RNA and the template for protein synthesis). Following discovery of the Rev response element (RRE) that mediates nucleocytoplasmic export of the full-length and singly-spliced human immunodeficiency virus type 1 (HIV-1) genome, equivalent cis-acting regulatory elements have been characterized for both complex and simple retroviruses and retroelements, together with the obligate viral and host proteins with which they interact. The exception to this is the gammaretrovirus family of simple retroviruses, exemplified by reticuloendotheliosis virus (REV), murine leukemia virus (MLV) and xenotropic MLV-related retrovirus (XMRV). In this commentary, we discuss our recent data that reported structural and functional data on the MLV/XMRV post-transcriptional regulatory element (designated the PTE). The PTE was characterized by a highly-structured region of multiple stem-loops (SL1 – SL7) overlapping the pro and 5′ portion of the pol open reading frames, comprising a bipartite export signal whose structures are separated by ∼1400 nt. In addition, structural probing suggested that SL3 nucleotides were involved in pseudoknot formation. These data, when compared with RNA transport elements of complex retroviruses (HIV) and simple murine retrotransposons (musD), collectively present an emerging picture that long-range tertiary interactions are critical mediators of their biological function. PMID:26442179

  16. Changes in lymphocyte and macrophage subsets due to morphine and ethanol treatment during a retrovirus infection causing murine AIDS

    SciTech Connect

    Watson, R.R.; Prabhala, R.H.; Darban, H.R.; Yahya, M.D.; Smith, T.L.

    1988-01-01

    The number of lymphocytes of various subsets were not significantly changed by the ethanol exposure except those showing activation markers which were reduced. The percentage of peripheral blood cells showing markers for macrophage functions and their activation were significantly reduced after binge use of ethanol. Ethanol retarded suppression of cells by retroviral infection. However by 25 weeks of infection there was a 8.6% survival in the ethanol fed mice infected with retrovirus which was much less than virally infected controls. Morphine treatment also increased the percentage of cells with markers for macrophages and activated macrophages in virally infected mice, while suppressing them in uninfected mice. The second and third morphine injection series suppressed lymphocyte T-helper and T-suppressor cells, but not total T cells. However, suppression by morphine was significantly less during retroviral disease than suppression caused by the virus only. At 25 weeks of infection 44.8% of morphine treated, infected mice survived.

  17. Human endogenous retrovirus expression is inversely related with the up-regulation of interferon-inducible genes in the skin of patients with lichen planus.

    PubMed

    Nogueira, Marcelle Almeida de Sousa; Gavioli, Camila Fátima Biancardi; Pereira, Nátalli Zanete; de Carvalho, Gabriel Costa; Domingues, Rosana; Aoki, Valéria; Sato, Maria Notomi

    2015-04-01

    Lichen planus (LP) is a common inflammatory skin disease of unknown etiology. Reports of a common transactivation of quiescent human endogenous retroviruses (HERVs) support the connection of viruses to the disease. HERVs are ancient retroviral sequences in the human genome and their transcription is often deregulated in cancer and autoimmune diseases. We explored the transcriptional activity of HERV sequences as well as the antiviral restriction factor and interferon-inducible genes in the skin from LP patients and healthy control (HC) donors. The study included 13 skin biopsies from patients with LP and 12 controls. Real-time PCR assay identified significant decrease in the HERV-K gag and env mRNA expression levels in LP subjects, when compared to control group. The expressions of HERV-K18 and HERV-W env were also inhibited in the skin of LP patients. We observed a strong correlation between HERV-K gag with other HERV sequences, regardless the down-modulation of transcripts levels in LP group. In contrast, a significant up-regulation of the cytidine deaminase APOBEC 3G (apolipoprotein B mRNA-editing), and the GTPase MxA (Myxovirus resistance A) mRNA expression level was identified in the LP skin specimens. Other transcript expressions, such as the master regulator of type I interferon-dependent immune responses, STING (stimulator of interferon genes) and IRF-7 (interferon regulatory factor 7), IFN-β and the inflammassome NALP3, had increased levels in LP, when compared to HC group. Our study suggests that interferon-inducible factors, in addition to their role in innate immunity against exogenous pathogens, contribute to the immune control of HERVs. Evaluation of the balance between HERV and interferon-inducible factor expression could possibly contribute to surveillance of inflammatory/malignant status of skin diseases. PMID:25384438

  18. Absence of Replication of Porcine Endogenous Retrovirus and Porcine Lymphotropic Herpesvirus Type 1 with Prolonged Pig Cell Microchimerism after Pig-to-Baboon Xenotransplantation▿

    PubMed Central

    Issa, Nicolas C.; Wilkinson, Robert A.; Griesemer, Adam; Cooper, David K. C.; Yamada, Kazuhiko; Sachs, David H.; Fishman, Jay A.

    2008-01-01

    Porcine endogenous retrovirus (PERV), porcine cytomegalovirus (PCMV), and porcine lymphotropic herpesvirus (PLHV) are common porcine viruses that may be activated with immunosuppression for xenotransplantation. Studies of viral replication or transmission are possible due to prolonged survival of xenografts in baboon recipients from human decay-accelerating factor transgenic or α-1,3-galactosyltransferase gene knockout miniature swine. Ten baboons underwent xenotransplantation with transgenic pig organs. Graft survival was 32 to 179 days. Recipient serial samples of peripheral blood mononuclear cells (PBMC) and plasma were analyzed for PCMV, PERV, and PLHV-1 nucleic acids and viral replication using quantitative PCR assays. The PBMC contained PERV proviral DNA in 10 animals, PLHV-1 DNA in 6, and PCMV in 2. PERV RNA was not detected in any PBMC or serum samples. Plasma PLHV-1 DNA was detected in one animal. Pig cell microchimerism (pig major histocompatibility complex class I and pig mitochondrial cytochrome c oxidase subunit II sequences) was present in all recipients with detectable PERV or PLHV-1 (85.5%). Productive infection of PERV or PLHV-1 could not be demonstrated. The PLHV-1 viral load did not increase in serum over time, despite prolonged graft survival and pig cell microchimerism. There was no association of viral loads with the nature of exogenous immune suppression. In conclusion, PERV provirus and PLHV-1 DNA were detected in baboons following porcine xenotransplantation. Viral detection appeared to be due to persistent pig cell microchimerism. There was no evidence of productive infection in recipient baboons for up to 6 months of xenograft function. PMID:18829759

  19. Human endogenous retrovirus type W envelope expression in blood and brain cells provides new insights into multiple sclerosis disease

    PubMed Central

    Germi, Raphaëlle; Bernard, Corinne; Garcia-Montojo, Marta; Deluen, Cécile; Farinelli, Laurent; Faucard, Raphaël; Veas, Francisco; Stefas, Ilias; Fabriek, Babs O; Van-Horssen, Jack; Van-der-Valk, Paul; Gerdil, Claire; Mancuso, Roberta; Saresella, Marina; Clerici, Mario; Marcel, Sébastien; Creange, Alain; Cavaretta, Rosella; Caputo, Domenico; Arru, Giannina; Morand, Patrice; Lang, Alois B; Sotgiu, Stefano; Ruprecht, Klemens; Rieckmann, Peter; Villoslada, Pablo; Chofflon, Michel; Boucraut, Jose; Pelletier, Jean; Hartung, Hans-Peter

    2012-01-01

    Background: The envelope protein from multiple sclerosis (MS) associated retroviral element (MSRV), a member of the Human Endogenous Retroviral family ‘W’ (HERV-W), induces dysimmunity and inflammation. Objective: The objective of this study was to confirm and specify the association between HERV-W/MSRV envelope (Env) expression and MS. Methods: 103 MS, 199 healthy controls (HC) and controls with other neurological diseases (28), chronic infections (30) or autoimmunity (30) were analysed with an immunoassay detecting Env in serum. Env RNA or DNA copy numbers in peripheral blood mononuclear cells (PBMC) were determined by a quantitative polymerase chain reaction (PCR). Env was detected by immunohistology in the brains of patients with MS with three specific monoclonals. Results: Env antigen was detected in a serum of 73% of patients with MS with similar prevalence in all clinical forms, and not in chronic infection, systemic lupus, most other neurological diseases and healthy donors (p<0.01). Cases with chronic inflammatory demyelinating polyneuropathy (5/8) and rare HC (4/103) were positive. RNA expression in PBMC and DNA copy numbers were significantly elevated in patients with MS versus HC (p<0.001). In patients with MS, DNA copy numbers were significantly increased in chronic progressive MS (secondary progressive MS vs relapsing–remitting MS (RRMS) p<0.001; primary progressive MS vs RRMS –<0.02). Env protein was evidenced in macrophages within MS brain lesions with particular concentrations around vascular elements. Conclusion: The association between MS disease and the MSRV-type HERV-W element now appears quite strong, as evidenced ex-vivo from serum and PBMC with post-mortem confirmation in brain lesions. Chronic progressive MS, RRMS and clinically isolated syndrome show different ELISA (Enzyme-Linked Immunosorbent Assay) and/or PCR profiles suggestive of an increase with disease evolution, and amplicon sequencing confirms the association with

  20. Intraventricular injections of mesenchymal stem cells activate endogenous functional remyelination in a chronic demyelinating murine model

    PubMed Central

    Cruz-Martinez, P; González-Granero, S; Molina-Navarro, M M; Pacheco-Torres, J; García-Verdugo, J M; Geijo-Barrientos, E; Jones, J; Martinez, S

    2016-01-01

    Current treatments for demyelinating diseases are generally only capable of ameliorating the symptoms, with little to no effect in decreasing myelin loss nor promoting functional recovery. Mesenchymal stem cells (MSCs) have been shown by many researchers to be a potential therapeutic tool in treating various neurodegenerative diseases, including demyelinating disorders. However, in the majority of the cases, the effect was only observed locally, in the area surrounding the graft. Thus, in order to achieve general remyelination in various brain structures simultaneously, bone marrow-derived MSCs were transplanted into the lateral ventricles (LVs) of the cuprizone murine model. In this manner, the cells may secrete soluble factors into the cerebrospinal fluid (CSF) and boost the endogenous oligodendrogenic potential of the subventricular zone (SVZ). As a result, oligodendrocyte progenitor cells (OPCs) were recruited within the corpus callosum (CC) over time, correlating with an increased myelin content. Electrophysiological studies, together with electron microscopy (EM) analysis, indicated that the newly formed myelin correctly enveloped the demyelinated axons and increased signal transduction through the CC. Moreover, increased neural stem progenitor cell (NSPC) proliferation was observed in the SVZ, possibly due to the tropic factors released by the MSCs. In conclusion, the findings of this study revealed that intraventricular injections of MSCs is a feasible method to elicit a paracrine effect in the oligodendrogenic niche of the SVZ, which is prone to respond to the factors secreted into the CSF and therefore promoting oligodendrogenesis and functional remyelination. PMID:27171265

  1. Association of murine lupus and thymic full-length endogenous retroviral expression maps to a bone marrow stem cell

    SciTech Connect

    Krieg, A.M.; Gourley, M.F.; Steinberg, A.D. )

    1991-05-01

    Recent studies of thymic gene expression in murine lupus have demonstrated 8.4-kb (full-length size) modified polytropic (Mpmv) endogenous retroviral RNA. In contrast, normal control mouse strains do not produce detectable amounts of such RNA in their thymuses. Prior studies have attributed a defect in experimental tolerance in murine lupus to a bone marrow stem cell rather than to the thymic epithelium; in contrast, infectious retroviral expression has been associated with the thymic epithelium, rather than with the bone marrow stem cell. The present study was designed to determine whether the abnormal Mpmv expression associated with murine lupus mapped to thymic epithelium or to a marrow precursor. Lethally irradiated control and lupus-prone mice were reconstituted with T cell depleted bone marrow; one month later their thymuses were studied for endogenous retroviral RNA and protein expression. Recipients of bone marrow from nonautoimmune donors expressed neither 8.4-kb Mpmv RNA nor surface MCF gp70 in their thymuses. In contrast, recipients of bone marrow from autoimmune NZB or BXSB donors expressed thymic 8.4-kb Mpmv RNA and mink cell focus-forming gp70. These studies demonstrate that lupus-associated 8.4-kb Mpmv endogenous retroviral expression is determined by bone marrow stem cells.

  2. Perspectives on retroviruses and the etiologic agent of AIDS.

    PubMed Central

    Hsiung, G. D.

    1987-01-01

    In 1911, the first retrovirus was described: the Rous sarcoma virus, an avian retrovirus. Forty years later the murine leukemic virus, a mouse retrovirus, was reported. Although many other retroviruses from non-primate species were identified during the 1960s, the first primate retrovirus was not recognized until it was isolated from a monkey tumor in 1970. The search for human retroviruses in human leukemic cells remained unsuccessful at that time. Facilitated by the discovery of T-cell growth factor, a substance used for the propagation of human leukocytes in cultures, the first human retrovirus was discovered in 1980. Soon thereafter, in 1983, another human retrovirus, human immunodeficiency virus (HIV), was reported and implicated as the etiologic agent of AIDS. The isolation and identification of HIV has stimulated much interest in the study of human retroviruses and the control of this new viral disease. Images FIG. 2 FIG. 3 PMID:2829449

  3. Novel Denisovan and Neanderthal Retroviruses

    PubMed Central

    Huntley, Derek; Aiewsakun, Pakorn; Kanda, Ravinder K.; Lynn, Claire; Tristem, Michael

    2014-01-01

    Following the recent availability of high-coverage genomes for Denisovan and Neanderthal hominids, we conducted a screen for endogenized retroviruses, identifying six novel, previously unreported HERV-K(HML2) elements (HERV-K is human endogenous retrovirus K). These elements are absent from the human genome (hg38) and appear to be unique to archaic hominids. These findings provide further evidence supporting the recent activity of the HERV-K(HML2) group, which has been implicated in human disease. They will also provide insights into the evolution of archaic hominids. PMID:25142605

  4. Protective efficacy of a human endogenous retrovirus envelope-coated, nonreplicable, baculovirus-based hemagglutin vaccine against pandemic influenza H1N1 2009.

    PubMed

    Choi, Jae-Yoo; Gwon, Yong-Dae; Kim, Jeong-Ki; Cho, Yeon-Dong; Heo, Yoon-Ki; Cho, Han-Sam; Choi, Tae-Jin; Poo, Ha-Ryoung; Oh, Yu-Kyoung; Kim, Young Bong

    2013-01-01

    Despite the advantages of DNA vaccines, overcoming their lower efficacy relative to that of conventional vaccines remains a challenge. Here, we constructed a human endogenous retrovirus (HERV) envelope-coated, nonreplicable, baculovirus-based HA vaccine against swine influenza A/California/04/2009(H1N1) hemagglutin (HA) (AcHERV-sH1N1-HA) as an alternative to conventional vaccines and evaluated its efficacy in two strains of mice, BALB/c and C57BL/6. A commercially available, killed virus vaccine was used as a positive control. Mice were intramuscularly administered AcHERV-sH1N1-HA or the commercial vaccine and subsequently given two booster injections. Compared with the commercial vaccine, AcHERV-sH1N1-HA induced significantly higher levels of cellular immune responses in both BALB/c and C57BL/6 mice. Unlike cellular immune responses, humoral immune responses depended on the strain of mice. Following immunization with AcHERV-sH1N1-HA, C57BL/6 mice showed HA-specific IgG titers 10- to 100-fold lower than those of BALB/c mice. In line with the different levels of humoral immune responses, the survival of immunized mice after intranasal challenge with sH1N1 virus (A/California/04/2009) depended on the strain. After challenge with 10-times the median lethal dose (MLD50) of sH1N1 virus, 100% of BALB/c mice immunized with the commercial vaccine or AcHERV-sH1N1-HA survived. In contrast, C57BL/6 mice immunized with AcHERV-sH1N1-HA or the commercial vaccine showed 60% and 70% survival respectively, after challenge with sH1N1 virus. In all mice, virus titers and results of histological analyses of lung tissues were consistent with the survival data. Our results indicate the importance of humoral immune response as a major defense system against influenza viral infection. Moreover, the complete survival of BALB/c mice immunized with AcHERV-sH1N1-HA after challenge with sH1N1 virus suggests the potential of baculoviral vector-based vaccines to achieve an efficacy comparable to

  5. A Single Amino Acid Substitution in a Segment of the CA Protein within Gag That Has Similarity to Human Immunodeficiency Virus Type 1 Blocks Infectivity of a Human Endogenous Retrovirus K Provirus in the Human Genome ▿

    PubMed Central

    Heslin, David J.; Murcia, Pablo; Arnaud, Frederick; Van Doorslaer, Koenraad; Palmarini, Massimo; Lenz, Jack

    2009-01-01

    Human endogenous retrovirus K (HERV-K) is the most intact retrovirus in the human genome. However, no single HERV-K provirus in the human genome today appears to be infectious. Since the Gag protein is the central component for the production of retrovirus particles, we investigated the abilities of Gag from two HERV-K proviruses to support production of virus-like particles and viral infectivity. HERV-K113 has full-length open reading frames for all viral proteins, while HERV-K101 has a full-length gag open reading frame and is expressed in human male germ cell tumors. The Gag of HERV-K101 allowed production of viral particles and infectivity, although at lower levels than observed with a consensus sequence Gag. Thus, including HERV-K109, at least two HERV-K proviruses in human genome today have functional Gag proteins. In contrast, HERV-K113 Gag supported only very low levels of particle production, and no infectivity was detectable due to a single amino acid substitution (I516M) near the extreme C terminus of the CA protein within Gag. The sequence of this portion of HERV-K CA showed similarities to that of human immunodeficiency virus type 1 and other primate immunodeficiency viruses. The extreme C terminus of CA may be a general determinant of retrovirus particle production. In addition, precise mapping of the defects in HERV-K proviruses as was done here identifies the key polymorphisms that need to be analyzed to assess the possible existence of infectious HERV-K alleles within the human population. PMID:19004950

  6. Retrovirus-induced murine motor neuron disease: mapping the determinant of spongiform degeneration within the envelope gene.

    PubMed Central

    Paquette, Y; Hanna, Z; Savard, P; Brousseau, R; Robitaille, Y; Jolicoeur, P

    1989-01-01

    The Cas-Br-E murine leukemia virus (MuLV) induces a degenerative myeloencephalopathy leading to hind-limb paralysis when inoculated into newborn mice. To map the viral DNA sequences encoding the determinant of neurological degeneration, we constructed chimeric viruses in vitro with parental genomes from Cas-Br-E MuLV and from nonparalytogenic MuLVs. We found that a 1.5-kilobase-pair env Cas-Br-E fragment was sufficient to confer the full paralysis-inducing potential to chimeric viruses. This region encodes the 19 carboxyl-terminal residues of the leader sequence, all of gp70, and the 45 amino-terminal residues of the transmembrane protein (p15E). Within this env region, we identified a 372-base-pair fragment which was necessary for the full paralysis-inducing potential of the virus and which influenced the development of the disease in a strain-dependent manner. This domain encodes the 19 carboxyl-terminal residues of the leader peptide and the first 67 amino-terminal residues of gp70. We propose that Cas-Br-E MuLV induces spongiform degeneration through binding of its gp70 to a specific cellular receptor. Images PMID:2542954

  7. The human endogenous retrovirus K(HML-2) has a broad envelope-mediated cellular tropism and is prone to inhibition at a post-entry, pre-integration step.

    PubMed

    Kramer, Philipp; Lausch, Veronika; Volkwein, Alexander; Hanke, Kirsten; Hohn, Oliver; Bannert, Norbert

    2016-01-01

    The HERV-K(HML-2) family is the most recent addition to the collection of human endogenous retroviruses. It comprises proviruses that encode functional proteins that can assemble into replication defective particles carrying the envelope protein. Using a reconstituted HERV-K113 envelope sequence, we have analyzed its ability to mediate entry into a set of 33 cell lines from 10 species. Of these, 30 were permissive, demonstrating an amphotropism consistent with a broad expression of receptor protein(s). In an initial effort to identify a receptor for HERV-K(HML-2) we investigated whether transferrin receptor 1 and hyaluronidase 2, known cellular receptors of the closely related betaretroviruses mouse mammary tumor virus (MMTV) and Jaagsiekte sheep retrovirus (JSRV), could facilitate HERV-K(HML-2) entry. However, neither of these proteins could serve as a receptor for HERV-K(HML-2). Moreover, during attempts to further characterize the tropism of HERV-K(HML-2), we identified a cellular activity that inhibits infection at a post-entry, pre-integration step. PMID:26517399

  8. A replication-competent retrovirus arising from a split-function packaging cell line was generated by recombination events between the vector, one of the packaging constructs, and endogenous retroviral sequences.

    PubMed

    Chong, H; Starkey, W; Vile, R G

    1998-04-01

    Previously we reported the presence of a replication-competent retrovirus in supernatant from a vector-producing line derived from a widely used split-function amphotropic packaging cell line. Rigorous routine screening of all retroviral stocks produced in our laboratory has not, previously or since, indicated the presence of such a virus. Replication-competent retroviruses have never previously been used in our laboratory, and stringent screening of all routinely used cell lines has not revealed the presence of any helper viruses. Therefore, it is highly unlikely that this virus represents an adventitious cross-contaminant or had been imported unknowingly with our cell line stocks. PCR studies with DNA from infected cell lines and Northern blot analysis and reverse transcriptase PCR with RNA from infected cells suggest that the helper virus arose by recombination events, at sites of partial homology, between sequences in the vector, one of the packaging constructs, and endogenous retroviral elements. These recombinations were not present in stocks of the packaging cell line or in an initial stock of the vector-producing line, indicating that these events occurred while the vector-producing line was being passaged for harvest of supernatant stocks. PMID:9525583

  9. KOALA RETROVIRUS: A REVIEW.

    PubMed

    Kinney, Matthew E; Pye, Geoffrey W

    2016-06-01

    Koala retrovirus (KoRV) is a gammaretrovirus that has been identified in both captive and free-ranging koalas ( Phascolarctos cinereus ) with variable geographic distribution in Australia. KoRV is capable of both exogenous and endogenous transmission, which provides an interesting research platform for scientists to study active retrovirus endogenization into a host genome and offers veterinary scientists an opportunity to examine the clinical consequences of KoRV infection in koalas. Causation between KoRV and frequently recognized clinical conditions associated with immune suppression and neoplasia in koalas has not been definitively established, however research continues to evaluate a potential association. Three KoRV variants, KoRV-A, KoRV-B, and KoRV-J, have been the most thoroughly described and preliminary evidence suggests KoRV variability may be fundamental in host pathogenicity. In addition to reviewing what is currently known about KoRV, this article discusses treatment, management, and future research directions. PMID:27468008

  10. Generation of mink cell focus-forming viruses by Friend murine leukemia virus: recombination with specific endogenous proviral sequences.

    PubMed Central

    Evans, L H; Cloyd, M W

    1984-01-01

    A family of recombinant mink cell focus-forming viruses (MCF) was derived by inoculation of NFS mice with a Friend murine leukemia virus, and their genomes were analyzed by RNase T1-resistant oligonucleotide fingerprinting. The viruses were obtained from the thymuses and spleens of preleukemic and leukemic animals and were evaluated for dualtropism and oncogenicity. All these isolates induced cytopathic foci on mink cells but could be classified into two groups based on their relative infectivities for SC-1 (mouse) or mink (ATCC CCL64) cells. One group of Friend MCFs (F-MCFs) (group I) exhibited approximately equal infectivities for SC-1 and mink cells, whereas a second group (group II) infected mink cells 1,000- to 10,000-fold more efficiently than SC-1 cells. Structural analyses of the F-MCFs revealed that group I and group II viruses correlated with recombination of Friend murine leukemia virus with two distinct, but closely related, endogenous NFS proviral sequences. No correlation was found between the type of F-MCF and the tissue of origin or the disease state of the animal. Furthermore, none of the F-MCF isolates were found to be oncogenic in NFS/N or AKR/J mice. F-MCFs of both groups underwent extensive substitution of ecotropic sequences, involving much of the gag and env genes of group I F-MCFs and most of the gag, pol, and env genes of group II F-MCFs. All F-MCF isolates retained the 3' terminal U3 region of Friend murine leukemia virus. Comparison of the RNAs of the F-MCFs with RNAs of MCFs derived from NFS.Akv-1 or NFS.Akv-2 mice indicated that the F-MCFs were derived from NFS proviral sequences which are distinct from the sequences contained in NFS.Akv MCF isolates. This result suggested that recombination with particular endogenous proviral sequences to generate MCFs may be highly specific for a given murine leukemia virus. Images PMID:6422051

  11. Angiotensin II-induced hypertrophy of cultured murine proximal tubular cells is mediated by endogenous transforming growth factor-beta.

    PubMed Central

    Wolf, G; Mueller, E; Stahl, R A; Ziyadeh, F N

    1993-01-01

    Previous studies by our group have demonstrated that angiotensin II (ANG II), as a single factor in serum-free medium, induces cellular hypertrophy of a cultured murine proximal tubular cell line (MCT). The present study was performed to test the hypothesis that this growth effect was mediated by activation of endogenous transforming growth factor-beta (TGF-beta). Exogenous TGF-beta 1 (1 ng/ml) mimicked the growth effects observed with 10(-8) M ANG II (inhibition of DNA synthesis and induction of cellular hypertrophy). A neutralizing anti-TGF-beta antibody attenuated the ANG II-induced increase in de novo protein and total RNA synthesis as well as total protein content. This antibody also abolished the ANG II-mediated inhibition of [3H]thymidine incorporation into quiescent MCT cells. Control IgG or an unrelated antibody had no effect. A bioassay for TGF-beta using mink lung epithelial cells revealed that MCT cells treated with ANG II released active TGF-beta into the cell culture supernatant. Northern blot analysis and semi-quantitative cDNA amplification demonstrated increases in steady-state levels for TGF-beta 1 mRNA after ANG II stimulation of MCT cells, but not in a syngeneic murine mesangial cell line. Our data indicate that the ANG II-induced hypertrophy in MCT cells is mediated by synthesis and activation of endogenous TGF-beta. It is intriguing to speculate that TGF-beta may play a role in the early tubular cell hypertrophy and the subsequent interstitial scarring observed in several models of chronic renal injury that are characterized by increased activity of intrarenal ANG II. Images PMID:7690779

  12. Cure of murine thalassemia by bone marrow transplantation without eradication of endogenous stem cells

    SciTech Connect

    Wagemaker, G.; Visser, T.P.; van Bekkum, D.W.

    1986-09-01

    alpha-Thalassemic heterozygous (Hbath/+) mice were used to investigate the possible selective advantage of transplanted normal (+/+) hemopoietic cells. Without conditioning by total-body irradiation (TBI), infusion of large numbers of normal bone marrow cells failed to correct the thalassemic peripheral blood phenotype. Since the recipients' stem cells are normal with respect to number and differentiation capacity, it was thought that the transplanted stem cells were not able to lodge, or that they were not stimulated to proliferate. Therefore, a nonlethal dose of TBI was given to temporarily reduce endogenous stem cell numbers and hemopoiesis. TBI doses of 2 or 3 Gy followed by infusion of normal bone marrow cells proved to be effective in replacing the thalassemic red cells by normal red cells, whereas a dose of 1 Gy was ineffective. It is concluded that cure of thalassemia by bone marrow transplantation does not necessarily require eradication of thalassemic stem cells. Consequently, the objectives of conditioning regimens for bone marrow transplantation of thalassemic patients (and possibly other nonmalignant hemopoietic disorders) should be reconsidered.

  13. Retroviruses: Gaining an Understanding.

    ERIC Educational Resources Information Center

    DiSpezio, Michael A.

    1990-01-01

    Contrasted are DNA viruses, RNA viruses, and RNA retroviruses. The structure, genome, and replication of retroviruses are discussed. The discovery, structure, and action of the HIV virus are described. A list of 17 references is included. (CW)

  14. Retrovirus Entry by Endocytosis and Cathepsin Proteases

    PubMed Central

    Kubo, Yoshinao; Hayashi, Hideki; Matsuyama, Toshifumi; Sato, Hironori; Yamamoto, Naoki

    2012-01-01

    Retroviruses include infectious agents inducing severe diseases in humans and animals. In addition, retroviruses are widely used as tools to transfer genes of interest to target cells. Understanding the entry mechanism of retroviruses contributes to developments of novel therapeutic approaches against retrovirus-induced diseases and efficient exploitation of retroviral vectors. Entry of enveloped viruses into host cell cytoplasm is achieved by fusion between the viral envelope and host cell membranes at either the cell surface or intracellular vesicles. Many animal retroviruses enter host cells through endosomes and require endosome acidification. Ecotropic murine leukemia virus entry requires cathepsin proteases activated by the endosome acidification. CD4-dependent human immunodeficiency virus (HIV) infection is thought to occur via endosomes, but endosome acidification is not necessary for the entry whereas entry of CD4-independent HIVs, which are thought to be prototypes of CD4-dependent viruses, is low pH dependent. There are several controversial results on the retroviral entry pathways. Because endocytosis and endosome acidification are complicatedly controlled by cellular mechanisms, the retrovirus entry pathways may be different in different cell lines. PMID:23304142

  15. Koala Retroviruses: Evolution and Disease Dynamics.

    PubMed

    Xu, Wenqin; Eiden, Maribeth V

    2015-11-01

    A retroviral etiology for malignant neoplasias in koalas has long been suspected. Evidence for retroviral involvement was bolstered in 2000 by the isolation of a koala retrovirus (KoRV), now termed KoRV-A. KoRV-A is an endogenous retrovirus-a retrovirus that infects germ cells-a feature that makes it a permanent resident of the koala genome. KoRV-A lacks the genetic diversity of an exogenous retrovirus, a quality associated with the ability of a retrovirus to cause neoplasias. In 2013, a second KoRV isolate, KoRV-B, was obtained from koalas with lymphomas in the Los Angeles Zoo. Unlike KoRV-A, which is present in the genomes of all koalas in the United States, KoRV-B is restricted in its distribution and is associated with host pathology (neoplastic disease). Here, our current understanding of the evolution of endogenous and exogenous KoRVs, and the relationship between them, is reviewed to build a perspective on the future impact of these viruses on koala sustainability. PMID:26958909

  16. A retrovirus packages nascent host noncoding RNAs from a novel surveillance pathway

    PubMed Central

    Eckwahl, Matthew J.; Sim, Soyeong; Smith, Derek; Telesnitsky, Alice

    2015-01-01

    Although all retroviruses recruit host cell RNAs into virions, both the spectrum of RNAs encapsidated and the mechanisms by which they are recruited remain largely unknown. Here, we used high-throughput sequencing to obtain a comprehensive description of the RNAs packaged by a model retrovirus, murine leukemia virus. The major encapsidated host RNAs are noncoding RNAs (ncRNAs) and members of the VL30 class of endogenous retroviruses. Remarkably, although Moloney leukemia virus (MLV) assembles in the cytoplasm, precursors to specific tRNAs, small nuclear RNAs (snRNAs), and small nucleolar RNAs (snoRNAs) are all enriched in virions. Consistent with their cytoplasmic recruitment, packaging of both pre-tRNAs and U6 snRNA requires the nuclear export receptor Exportin-5. Adenylated and uridylated forms of these RNAs accumulate in cells and virions when the cytoplasmic exoribonuclease DIS3L2 and subunits of the RNA exosome are depleted. Together, our data reveal that MLV recruits RNAs from a novel host cell surveillance pathway in which unprocessed and unneeded nuclear ncRNAs are exported to the cytoplasm for degradation. PMID:25792599

  17. Frequent site-specific deletion of coliphage lambda murine sarcoma virus recombinants and its use in the identification of a retrovirus integration site.

    PubMed Central

    McClements, W L; Enquist, L W; Oskarsson, M; Sullivan, M; Vande Woude, G F

    1980-01-01

    Stocks of hybrid lambda phages carrying the complete integrated provirus of either m1 or HT1 Moloney murine sarcoma virus, as well as flanking host sequences, frequently contain significant numbers of phages carrying a specific deletion. This deletion arises from a recombination event between the terminally repeated sequences in the provirus that deletes the unique Moloney murine sarcoma virus sequences bracketed by the terminally repeated sequences. Physical mapping has shown that the deletion phage retains one complete copy of the terminally repeated sequence and the flanking mink host sequences. One such deletion, lambdaHT1r+, was used to characterize a mink genomic DNA sequence that contains an HT1 Moloney murine sarcoma virus integration site. This integration site sequence from normal mink cells was also cloned into phage lambda. An analysis of the heteroduplexes between the integration site and the lambdaHT1r+ deletion indicated that no major rearrangement of host sequences occurred upon integration of the Moloney murine sarcoma provirus. Images PMID:6255187

  18. Xenotropic retrovirus Bxv1 in human pancreatic β cell lines

    PubMed Central

    Kirkegaard, Jeannette S.; Ingvarsen, Signe; Diedisheim, Marc; Bricout-Neveu, Emilie; Grønborg, Mads; Frogne, Thomas; Scharfmann, Raphael; Madsen, Ole D.; Rescan, Claude; Albagli, Olivier

    2016-01-01

    It has been reported that endogenous retroviruses can contaminate human cell lines that have been passaged as xenotransplants in immunocompromised mice. We previously developed and described 2 human pancreatic β cell lines (EndoC-βH1 and EndoC-βH2) that were generated in this way. Here, we have shown that B10 xenotropic virus 1 (Bxv1), a xenotropic endogenous murine leukemia virus (MuLV), is present in these 2 recently described cell lines. We determined that Bxv1 was also present in SCID mice that were used for in vivo propagation of EndoC-βH1/2 cells, suggesting that contamination occurred during xenotransplantation. EndoC-βH1/2 cells released Bxv1 particles that propagated to human 293T and Mus dunni cells. Mobilization assays demonstrated that Bxv1 transcomplements defective MuLV-based retrovectors. In contrast, common rodent β cell lines, rat INS-1E and RIN-5F cells and mouse MIN6 and βTC3 cells, displayed either no or extremely weak xenotropic helper activity toward MuLV-based retrovectors, although xenotropic retrovirus sequences and transcripts were detected in both mouse cell lines. Bxv1 propagation from EndoC-βH1/2 to 293T cells occurred only under optimized conditions and was overall poorly efficient. Thus, although our data imply that MuLV-based retrovectors should be cautiously used in EndoC-βH1/2 cells, our results indicate that an involuntary propagation of Bxv1 from these cells can be easily avoided with good laboratory practices. PMID:26901817

  19. Host RNA Packaging by Retroviruses: A Newly Synthesized Story

    PubMed Central

    Eckwahl, Matthew J.; Telesnitsky, Alice

    2016-01-01

    ABSTRACT A fascinating aspect of retroviruses is their tendency to nonrandomly incorporate host cell RNAs into virions. In addition to the specific tRNAs that prime reverse transcription, all examined retroviruses selectively package multiple host cell noncoding RNAs (ncRNAs). Many of these ncRNAs appear to be encapsidated shortly after synthesis, before assembling with their normal protein partners. Remarkably, although some packaged ncRNAs, such as pre-tRNAs and the spliceosomal U6 small nuclear RNA (snRNA), were believed to reside exclusively within mammalian nuclei, it was demonstrated recently that the model retrovirus murine leukemia virus (MLV) packages these ncRNAs from a novel pathway in which unneeded nascent ncRNAs are exported to the cytoplasm for degradation. The finding that retroviruses package forms of ncRNAs that are rare in cells suggests several hypotheses for how these RNAs could assist retrovirus assembly and infectivity. Moreover, recent experiments in several laboratories have identified additional ways in which cellular ncRNAs may contribute to the retrovirus life cycle. This review focuses on the ncRNAs that are packaged by retroviruses and the ways in which both encapsidated ncRNAs and other cellular ncRNAs may contribute to retrovirus replication. PMID:26861021

  20. The International Xenotransplantation Association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes--chapter 5: Strategies to prevent transmission of porcine endogenous retroviruses.

    PubMed

    Denner, Joachim; Schuurman, Henk-Jan; Patience, Clive

    2009-01-01

    Xenotransplantation using porcine cells, tissues, or organs may offer a potential solution for the shortage of allogeneic human organs. Prior to the clinical use of porcine xenotransplants, three main hurdles must be overcome: immunologic rejection, physiologic incompatibility, and risk of transmission of porcine pathogens. Designated pathogen-free breeding of pigs can prevent transmission of most porcine microbes. However, this is not possible in the case of porcine endogenous retroviruses (PERV), which are integrated in the pig genome and can infect human cells in vitro. In order to assess the probability of transmission of PERV, a careful screening of the source pig herd is recommended. Two types of PERV are present in pigs, human-tropic PERV-A and PERV-B, which are both present in the genome of all pigs, and PERV-C, which is not ubiquitous and infects only pig cells. In addition to these viruses, recombinant PERV-A/C viruses have recently been described that (i) are able to infect human cells; (ii) are characterized by high titre replication; and (iii) are associated with proviruses that are de novo integrated in the DNA of somatic pig cells, but not yet in the pig germ line. The risks presented by PERV-A/C recombinant viruses could easily be eliminated by using pigs not containing PERV-C in their germ line, thereby effectively preventing recombination with PERV-A. Selection of PERV-C-free animals, if possible, therefore reduces the risk of PERV-A/C transmission to humans. Although it is unclear whether PERV-C may be transmitted in vivo from pig-to-pig, an infection of PERV-C-free animals with this virus may be prevented. To select pigs with low-level expression of PERV-A and PERV-B, it is recommended to apply assays based on real-time reverse transcriptase polymerase chain reaction (RT-PCR), which enables discrimination between pigs with high-level expression and low-level expression. Screening xenotransplant recipients for PERV transmission can be done in a

  1. Intracellularly Expressed Single-Domain Antibody against p15 Matrix Protein Prevents the Production of Porcine Retroviruses

    PubMed Central

    Dekker, Sylvia; Toussaint, Wendy; Panayotou, George; de Wit, Ton; Visser, Pim; Grosveld, Frank; Drabek, Dubravka

    2003-01-01

    The presence of porcine endogenous retroviruses presents a potential risk of transmission of infectious diseases (xenozoonosis) if tissues and organs from genetically modified pigs are to be used in xenotransplantation. Here, we report that intracellular expression of a llama single-domain antibody against p15, the matrix domain protein of the porcine endogenous retrovirus Gag polyprotein, blocks retrovirus production, providing the possibility of eliminating the risk of infection in xenotransplantation. PMID:14581550

  2. Retrovirus gene expression during the cell cycle. I. Virus production, synthesis, and expression of viral proteins in Rauscher murine leukemia virus-infected mouse cells.

    PubMed Central

    Balazs, I; Caldarella, J

    1981-01-01

    Synchronized mouse cells (JLS-V9) chronically infected with Rauscher murine leukemia virus were used to study virus production, the synthesis of gag and env precursor proteins, and the expression of env protein on the cell surface during the cell cycle. The amount of virus released into the medium by synchronized cells during a 30-min interval was determined by using the XC plaque assay and by measuring reverse transcriptase activity. The results show that virus production occurs during mitosis. Labeling of the cell surface of synchronized cells with 125I or with fluorescein-conjugated antiserum shows that the amount of gp 70env on the cell surface parallels cellular growth. Therefore, the cell cycle-dependent release of virus is not accompanied by similar variations in the amount of viral envelope protein on the cell surface. Immunoprecipitation of cells labeled with [35S]methionine, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was used to measure viral protein synthesis during the cell cycle. The rate of synthesis of gag precursor proteins show three maximums corresponding to the G1, middle S, and late S to G2 phases of the cell cycle. The rate of synthesis of env precursor proteins does not change, suggesting that in these cells the synthesis of these two gene products is controlled separately. Images PMID:7288918

  3. Expression of human adenosine deaminase in mice reconstituted with retrovirus-transduced hematopoietic stem cells

    SciTech Connect

    Wilson, J.M.; Danos, O.; Grossman, M.; Raulet, D.H.; Mulligan, R.C. )

    1990-01-01

    Recombinant retroviruses encoding human adenosine deaminase have been used to infect murine hematopoietic stem cells. In bone marrow transplant recipients reconstituted with the genetically modified cells, human ADA was detected in peripheral blood mononuclear cells of the recipients for at least 6 months after transplantation. In animals analyzed in detail 4 months after transplantation, human ADA and proviral sequences were detected in all hematopoietic lineages; in several cases, human ADA activity exceeded the endogenous activity. These studies demonstrate the feasibility of introducing a functional human ADA gene into hematopoietic stem cells and obtaining expression in multiple hematopoietic lineages long after transplantation. This approach should be helpful in designing effective gene therapies for severe combined immunodeficiency syndromes in humans.

  4. Retroviruses in invertebrates: the gypsy retrotransposon is apparently an infectious retrovirus of Drosophila melanogaster.

    PubMed Central

    Kim, A; Terzian, C; Santamaria, P; Pélisson, A; Purd'homme, N; Bucheton, A

    1994-01-01

    Retroviruses are commonly considered to be restricted to vertebrates. However, the genome of many eukaryotes contains mobile sequences known as retrotransposons with long terminal repeats (LTR retrotransposons) or viral retrotransposons, showing similarities with integrated proviruses of retroviruses, such as Ty elements in Saccharomyces cerevisiae, copia-like elements in Drosophila, and endogenous proviruses in vertebrates. The gypsy element of Drosophila melanogaster has LTRs and contains three open reading frames, one of which encodes potential products similar to gag-specific protease, reverse transcriptase, and endonuclease. It is more similar to typical retroviruses than to LTR retrotransposons. We report here experiments showing that gypsy can be transmitted by microinjecting egg plasma from embryos of a strain containing actively transposing gypsy elements into embryos of a strain originally devoid of transposing elements. Horizontal transfer is also observed when individuals of the "empty" stock are raised on medium containing ground pupae of the stock possessing transposing elements. These results suggest that gypsy is an infectious retrovirus and provide evidence that retroviruses also occur in invertebrates. Images PMID:8108403

  5. Retroviruses and amyotrophic lateral sclerosis

    PubMed Central

    Alfahad, Tariq; Nath, Avindra

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive, invariably fatal neurologic disorder resulting from upper and lower motor neuron degeneration, which typically develops during the sixth or seventh decade of life, and is diagnosed based on standard clinical criteria. Its underlying cause remains undetermined. The disease may occur with increased frequency within certain families, often in association with specific genomic mutations, while some sporadic cases have been linked to environmental toxins or trauma. Another possibility, first proposed in the 1970s, is that retroviruses play a role in pathogenesis. In this paper, we review the published literature for evidence that ALS is associated either with infection by an exogenous retrovirus or with the expression of human endogenous retroviral (HERV) sequences in cells of the central nervous system. A small percentage of persons infected with the human immunodeficiency virus-1 (HIV-1) or human T cell leukemia virus-1 (HTLV-1) develop ALS-like syndromes. While HTLV-1 associated ALS-like syndrome has several features that may distinguish it from classical ALS, HIV-infected patients may develop neurological manifestations that resemble classical ALS although it occurs at a younger age and they may show a dramatic improvement following the initiation of antiretroviral therapy. However, most patients with probable or definite ALS show no evidence of HIV-1 or HTLV-1 infection. In contrast, recent reports have shown a stronger association with HERV, as analysis of serum samples, and postmortem brain tissue from a number of patients with a classical ALS has revealed significantly increased expression of HERV-K, compared to controls. These findings suggest that endogenous retroviral elements are involved in the pathophysiology of ALS, but there is no evidence that they are the primary cause of the syndrome. PMID:23707220

  6. Differential effects of endogenous and exogenous interferon-gamma on immunoglobulin E, cellular infiltration, and airway responsiveness in a murine model of allergic asthma.

    PubMed

    Hofstra, C L; Van Ark, I; Hofman, G; Nijkamp, F P; Jardieu, P M; Van Oosterhout, A J

    1998-11-01

    The inflammatory response as seen in human allergic asthma is thought to be regulated by Th2 cells. It has been shown that interferon-gamma (IFN-gamma) can downregulate the proliferation of Th2 cells and therefore might be of therapeutic use. In the present study we have investigated the in vivo role of endogenous and exogenous IFN-gamma in a murine model with features reminiscent of human allergic asthma. IFN-gamma gene knockout (GKO) and wild-type mice were sensitized with ovalbumin and exposed to repeated ovalbumin aerosol challenges. In addition, wild-type mice were treated with intraperitoneal or nebulized recombinant murine IFN-gamma during the challenge period. Sensitized wild-type mice exhibited upregulated ovalbumin-specific IgE in serum, and airway hyperresponsiveness and infiltration of eosinophils and mononuclear cells in the bronchoalveolar lavage fluid (BALF) after ovalbumin challenge. In contrast, in GKO mice only reduced eosinophilic infiltration in the BALF was observed after ovalbumin challenge. In wild-type mice, parenteral IFN-gamma treatment downregulated ovalbumin-specific IgE levels in serum, and airway hyperresponsiveness and cellular infiltration in the BALF, whereas aerosolized IFN-gamma treatment only suppressed airway hyperresponsiveness. In vitro experiments showed that these effects of IFN-gamma appear not to be mediated via a direct effect on the cytokine production of antigen-specific Th2 cells. These data indicate that airway hyperresponsiveness can be downregulated by IFN-gamma locally in the airways, whereas for downregulation of IgE and cellular infiltration systemic IFN-gamma is needed. The present study shows that exogenous IFN-gamma can downregulate the allergic response via an antigen-specific T-cell independent mechanism, but at the same time endogenous IFN-gamma plays a role in an optimal response. PMID:9806748

  7. Proteasomal Degradation of TRIM5α during Retrovirus Restriction

    PubMed Central

    Rold, Christopher James; Aiken, Christopher

    2008-01-01

    The host protein TRIM5α inhibits retroviral infection at an early post-penetration stage by targeting the incoming viral capsid. While the detailed mechanism of restriction remains unclear, recent studies have implicated the activity of cellular proteasomes in the restriction of retroviral reverse transcription imposed by TRIM5α. Here, we show that TRIM5α is rapidly degraded upon encounter of a restriction-susceptible retroviral core. Inoculation of TRIM5α-expressing human 293T cells with a saturating level of HIV-1 particles resulted in accelerated degradation of the HIV-1-restrictive rhesus macaque TRIM5α protein but not the nonrestrictive human TRIM5α protein. Exposure of cells to HIV-1 also destabilized the owl monkey restriction factor TRIMCyp; this was prevented by addition of the inhibitor cyclosporin A and was not observed with an HIV-1 virus containing a mutation in the capsid protein that relieves restriction by TRIMCyp IVHIV. Likewise, human TRIM5α was rapidly degraded upon encounter of the restriction-sensitive N-tropic murine leukemia virus (N-MLV) but not the unrestricted B-MLV. Pretreatment of cells with proteasome inhibitors prevented the HIV-1-induced loss of both rhesus macaque TRIM5α and TRIMCyp proteins. We also detected degradation of endogenous TRIM5α in rhesus macaque cells following HIV-1 infection. We conclude that engagement of a restriction-sensitive retrovirus core results in TRIM5α degradation by a proteasome-dependent mechanism. PMID:18497858

  8. Ruthenium red preserves glycoprotein peplomers of C-type retroviruses for transmission electron microscopy.

    PubMed

    Fassel, T A; Raisch, K P; Chetty, N; Grossberg, S E; Kushnaryov, V M

    1998-07-01

    Peplomers, the glycoprotein projections of the outer viral envelope, are distinctive for many viruses. Peplomers of retroviral C-type particles are fragile and are not preserved in standard preparations for transmission electron microscopy of thin sections, whereas the peplomers of B- and D- type retroviruses are usually preserved. Ruthenium red, extensively used in transmission electron microscopy to enhance the preservation of glycosylated proteins, was used in the preparation of three retrovirus-producing lymphoblastoid cell lines: murine SC-1 cells producing the C-type murine leukemia retrovirus LP-BM5 that causes immunodeficiency, human DG-75 cells producing a murine leukemia retrovirus, and human C5/MJ cells producing human T-cell lymphotropic virus type I (HTLV-I). Fixation of cells was carried out with ruthenium red present in the glutaraldehyde, osmium tetroxide, and the ethanol dehydration through the 70% ethanol step. The detailed structure of peplomers of these three different viruses was well preserved. PMID:9735881

  9. Biochemical characterization of endogenous type C virus information in differentiated and undifferentiated murine teratocarcinoma-derived cell lines.

    PubMed Central

    Emanoil-Ravicovitch, R; Hojman-Montes-de-Oca, F; Robert, J; Garcette, M; Callahan, R; Peries, J; Boiron, M

    1980-01-01

    Undifferentiated teratocarcinoma cells express sixfold-higher levels of endogenous xenotropic type C virus-related RNA than differentiated cells. Three species of polyadenylated viral RNA (35S, 24S, and 14S) have been identified in the undifferentiated teratocarcinoma cells. Paradoxically, neither viral particles nor viral proteins have been detected in these cells. PMID:6246284

  10. A Novel Recombinant Retrovirus in the Genomes of Modern Birds Combines Features of Avian and Mammalian Retroviruses

    PubMed Central

    Henzy, Jamie E.; Gifford, Robert J.; Johnson, Welkin E.

    2014-01-01

    ABSTRACT Endogenous retroviruses (ERVs) represent ancestral sequences of modern retroviruses or their extinct relatives. The majority of ERVs cluster alongside exogenous retroviruses into two main groups based on phylogenetic analyses of the reverse transcriptase (RT) enzyme. Class I includes gammaretroviruses, and class II includes lentiviruses and alpha-, beta-, and deltaretroviruses. However, analyses of the transmembrane subunit (TM) of the envelope glycoprotein (env) gene result in a different topology for some retroviruses, suggesting recombination events in which heterologous env sequences have been acquired. We previously demonstrated that the TM sequences of five of the six genera of orthoretroviruses can be divided into three types, each of which infects a distinct set of vertebrate classes. Moreover, these classes do not always overlap the host range of the associated RT classes. Thus, recombination resulting in acquisition of a heterologous env gene could in theory facilitate cross-species transmissions across vertebrate classes, for example, from mammals to reptiles. Here we characterized a family of class II avian ERVs, “TgERV-F,” that acquired a mammalian gammaretroviral env sequence. Although TgERV-F clusters near a sister clade to alpharetroviruses, its genome also has some features of betaretroviruses. We offer evidence that this unusual recombinant has circulated among several avian orders and may still have infectious members. In addition to documenting the infection of a nongalliform avian species by a mammalian retrovirus, TgERV-F also underscores the importance of env sequences in reconstructing phylogenies and supports a possible role for env swapping in allowing cross-species transmissions across wide taxonomic distances. IMPORTANCE Retroviruses can sometimes acquire an envelope gene (env) from a distantly related retrovirus. Since env is a key determinant of host range, such an event affects the host range of the recombinant virus and

  11. Syncytin-A and syncytin-B, two fusogenic placenta-specific murine envelope genes of retroviral origin conserved in Muridae

    PubMed Central

    Dupressoir, Anne; Marceau, Geoffroy; Vernochet, Cécile; Bénit, Laurence; Kanellopoulos, Colette; Sapin, Vincent; Heidmann, Thierry

    2005-01-01

    Recently, we and others have identified two human endogenous retroviruses that entered the primate lineage 25–40 million years ago and that encode highly fusogenic retroviral envelope proteins (syncytin-1 and -2), possibly involved in the formation of the placenta syncytiotrophoblast layer generated by trophoblast cell fusion at the materno–fetal interface. A systematic in silico search throughout mouse genome databases presently identifies two fully coding envelope genes, present as unique copies and unrelated to any known murine endogenous retrovirus, that we named syncytin-A and -B. Quantitative RT-PCR demonstrates placenta-specific expression for both genes, with increasing transcript levels in this organ from 9.5 to 14.5 days postcoitum. In situ hybridization of placenta cryosections further localizes these transcripts in the syncytiotrophoblast-containing labyrinthine zona. Consistently, we show that both genes can trigger cell–cell fusion in ex vivo transfection assays, with distinct cell type specificities suggesting different receptor usage. Genes orthologous to syncytin-A and -B and disclosing a striking conservation of their coding status are found in all Muridae tested (mouse, rat, gerbil, vole, and hamster), dating their entry into the rodent lineage ≈20 million years ago. Together, these data strongly argue for a critical role of syncytin-A and -B in murine syncytiotrophoblast formation, thus unraveling a rather unique situation where two pairs of endogenous retroviruses, independently acquired by the primate and rodent lineages, would have been positively selected for a convergent physiological role. PMID:15644441

  12. Removal of xenotropic murine leukemia virus by nanocellulose based filter paper.

    PubMed

    Asper, M; Hanrieder, T; Quellmalz, A; Mihranyan, A

    2015-11-01

    The removal of xenotrpic murine leukemia virus (xMuLV) by size-exclusion filter paper composed of 100% naturally derived cellulose was validated. The filter paper was produced using cellulose nanofibers derived from Cladophora sp. algae. The filter paper was characterized using atomic force microscopy, scanning electron microscopy, helium pycnometry, and model tracer (100 nm latex beads and 50 nm gold nanoparticles) retention tests. Following the filtration of xMuLV spiked solutions, LRV ≥5.25 log10 TCID50 was observed, as limited by the virus titre in the feed solution and sensitivity of the tissue infectivity test. The results of the validation study suggest that the nanocellulose filter paper is useful for removal of endogenous rodent retroviruses and retrovirus-like particles during the production of recombinant proteins. PMID:26328471

  13. Partial molecular cloning of the JHK retrovirus using gammaretrovirus consensus PCR primers

    PubMed Central

    Halligan, Brian D; Sun, Hai-Yuan; Kushnaryov, Vladimir M; Grossberg, Sidney E

    2013-01-01

    The JHK virus (JHKV) was previously described as a type C retrovirus that has some distinctive ultrastructural features and replicates constitutively in a human B-lymphoblastoid cell line, JHK-3. In order to facilitate the cloning of sequences from JHKV, a series of partially degenerate consensus retroviral PCR primers were created by a data-driven design approach based on an alignment of 14 diverse gammaretroviral genomes. These primers were used in the PCR amplification of purified JHK virion cDNA, and ana lysis of the resulting amplified sequence indicates that the JHKV is in the murine leukemia virus (MLV) family. The JHK sequence is nearly identical to the corresponding region of the Bxv-1 endogenous mouse retrovirus (GenBank accession AC115959) and distinct from XMRV. JHKV gag-specific amplification was demonstrated with nucleic acids from uncultivated, frozen, peripheral blood mononuclear cells (PBMCs) of the index patient, but not in PBMCs from nine healthy blood donors. Unlike earlier reports, in which MLV-like sequences were identified in human source material, which may have been due to murine contamination, budding retrovirions were demonstrated repeatedly by electron microscopy in uncultivated lymphocytes of the index patient that were morphologically identical in their development to the virions in the JHK-3 cells, and immunological evidence was obtained that the index patient produced IgG antibodies that bound to the budding viral particles in patient PBMCs and in the JHK-3 cells. These data indicate that the patient had been infected by JHKV, lending significance to the demonstration of JHKV amplicons in nucleic acids of the patient’s PBMCs. In future studies, the PCR primer sets described herein may expand the detection of an amplifiable subset of viruses related to MLV. PMID:24159361

  14. A model of secreting murine mammary epithelial HC11 cells comprising endogenous Bcrp/Abcg2 expression and function.

    PubMed

    Tallkvist, Jonas; Yagdiran, Yagmur; Danielsson, Louise; Oskarsson, Agneta

    2015-04-01

    Breast cancer resistance protein (Bcrp/Abcg2) and multidrug transporter 1 (Mdr1/Abcb1) are efflux proteins located in the apical membrane of mammary epithelial cells (MEC). Bcrp is induced in MEC during gestation and lactation, while Mdr1 is down-regulated during lactation. Numerous drugs and toxic compounds are known to be actively secreted into milk by Bcrp, but most chemicals have not been investigated in this respect, emphasizing the need for functional Bcrp studies in an established cell line with secreting mammary epithelial cells. The present study was undertaken to examine expressions of Bcrp and Mdr1 in mammary epithelial HC11 cells, derived from a mid-gestational murine mammary gland. In addition, Bcrp function was assessed by transport experiments with mitoxantrone (MX) in undifferentiated HC11 cells, in HC11 cells subjected to Bcrp RNA interference (RNAi), as well as in HC11 cells stimulated to differentiate by treatment with lactogenic hormones. Differentiated HC11 cells organized into alveolar-resembling structures and gene expression of the major milk protein β-casein was induced, whereas undifferentiated cells formed monolayers with lower β-casein expression. Bcrp and Mdr1 gene and protein were expressed in both undifferentiated and differentiated HC11 cells. Differentiation of HC11 cells resulted in increased Bcrp protein expression, while Mdr1 gene and protein expressions were reduced. The Bcrp inhibitor elacridar (GF120918) reduced secretion and increased accumulation of MX in both undifferentiated and differentiated HC11 cells. Silencing of the Bcrp gene caused an increased accumulation of MX. The results indicate that the HC11 cell model provides a promising tool to investigate transport of potential Bcrp substrates in mammary epithelial cells. PMID:25791223

  15. Characterization of a novel murine leukemia virus-related subgroup within mammals.

    PubMed Central

    Tristem, M; Kabat, P; Lieberman, L; Linde, S; Karpas, A; Hill, F

    1996-01-01

    The murine leukemia virus (MuLV)-related retroviruses are one of seven genera which together constitute the family Retroviridae. They are widespread as both endogenous and exogenous agents within vertebrates and have been associated with a variety of malignancies and other disorders. We isolated and characterized 12 endogenous representatives of this genus from a number of mammalian hosts. Subsequent sequence analysis revealed that the isolated viruses cluster into two clearly distinct groups. All of the exogenous MuLV-related retroviruses which have been isolated to date, as well as several endogenous examples, fall into the first group, whereas the second group is represented solely by endogenous representatives, including human endogenous retrovirus type E (HERV.E). The two groups are widespread within mammals, with both often present within one animal species. Despite this, there is no evidence to date that recombination between members of the different groups has occurred. Genetic distances and several other properties of the HERV.E genome suggest that if exogenous members of this subgroup exist, they are likely to have biological properties different from those of the other exogenous viruses of this genus. Several of these viruses are known to have been integrated within their hosts' genomes for a long period of time, and a most recent divergence date for the MuLV and HERV.E subgroups can thus be proposed. This date, approximately 30 million years ago, is the most recent date possible, and it is probable that the actual period of time since their divergence is significantly longer. PMID:8892961

  16. Specific antigenic relationships between the RNA-dependent DNA polymerases of avian reticuloendotheliosis viruses and mammalian type C retroviruses.

    PubMed Central

    Bauer, G; Temin, H M

    1980-01-01

    Immunoglobulin G directed against the DNA polymerase of Rauscher murine leukemia virus (R-MuLV) could bind to 125I-labeled DNA polymerase of spleen necrosis virus (SNV), a member of the reticuloendotheliosis virus (REV) species. Competition radioimmunoassays showed the specificity of this cross-reaction. The antigenic determinants common to SNV and R-MuLV DNA polymerases were shared completely by the DNA polymerases of Gross MuLV, Moloney MuLV, RD 114 virus, REV-T, and duck infectious anemia virus. Baboon endogenous virus and chicken syncytial virus competed partially for antibodies directed against the common antigenic determinants of SNV and R-MuLV DNA polymerases. DNA polymerases of avian leukosis viruses, pheasant viruses, and mammalian type B and D retroviruses and particles with RNA-dependent DNA polymerase activity from the allantoic fluid of normal chicken eggs and from the medium of a goose cell culture did not compete for the antibodies directed against the common antigenic determinants of SNV and R-MuLV DNA polymerases. We also present data about a factor in normal mammalian immunoglobulin G that specifically inhibits the DNA polymerases of REV and mammalian type C retrovirus DNA polymerases. PMID:6154804

  17. About the origin of retroviruses and the co-evolution of the gypsy retrovirus with the Drosophila flamenco host gene.

    PubMed

    Pélisson, A; Teysset, L; Chalvet, F; Kim, A; Prud'homme, N; Terzian, C; Bucheton, A

    1997-01-01

    The gypsy element of Drosophila melanogaster is the first retrovirus identified so far in invertebrates. According to phylogenetic data, gypsy belongs to the same group as the Ty3 class of LTR-retrotransposons, which suggests that retroviruses evolved from this kind of retroelements before the radiation of vertebrates. There are other invertebrate retroelements that are also likely to be endogenous retroviruses because they share with gypsy some structural and functional retroviral-like characteristics. Gypsy is controlled by a Drosophila gene called flamenco, the restrictive alleles of which maintain the retrovirus in a repressed state. In permissive strains, functional gypsy elements transpose at high frequency and produce infective particles. Defective gypsy proviruses located in pericentromeric heterochromatin of all strains seem to be very old components of the genome of Drosophila melanogaster, which indicates that gypsy invaded this species, or an ancestor, a long time ago. At that time, Drosophila melanogaster presumably contained permissive alleles of the flamenco gene. One can imagine that the species survived to the increase of genetic load caused by the retroviral invasion because restrictive alleles of flamenco were selected. The characterization of a retrovirus in Drosophila, one of the most advanced model organisms for molecular genetics, provides us with an exceptional clue to study how a species can resist a retroviral invasion. PMID:9440256

  18. Evolution and Distribution of Class II-Related Endogenous Retroviruses†

    PubMed Central

    Gifford, Robert; Kabat, Peter; Martin, Joanne; Lynch, Clare; Tristem, Michael

    2005-01-01

    Endogenous retroviruses (ERVs) are widespread in vertebrate genomes and have been loosely grouped into “classes” on the basis of their phylogenetic relatedness to the established genera of exogenous retroviruses. Four of these genera—the lentiviruses, alpharetroviruses, betaretroviruses, and deltaretroviruses—form a well-supported clade in retroviral phylogenies, and ERVs that group with these genera have been termed class II ERVs. We used PCR amplification and sequencing of retroviral fragments from more than 130 vertebrate taxa to investigate the evolution of the class II retroviruses in detail. We confirm that class II retroviruses are largely confined to mammalian and avian hosts and provide evidence for a major novel group of avian retroviruses, and we identify additional members of both the alpha- and the betaretrovirus genera. Phylogenetic analyses demonstrated that the avian and mammalian viruses form distinct monophyletic groups, implying that interclass transmission has occurred only rarely during the evolution of the class II retroviruses. In contrast to previous reports, the lentiviruses clustered as sister taxa to several endogenous retroviruses derived from rodents and insectivores. This topology was further supported by the shared loss of both the class II PR-Pol frameshift site and the class II retrovirus G-patch domain. PMID:15858031

  19. Endogenized viral sequences in mammals.

    PubMed

    Parrish, Nicholas F; Tomonaga, Keizo

    2016-06-01

    Reverse-transcribed RNA molecules compose a significant portion of the human genome. Many of these RNA molecules were retrovirus genomes either infecting germline cells or having done so in a previous generation but retaining transcriptional activity. This mechanism itself accounts for a quarter of the genomic sequence information of mammals for which there is data. We understand relatively little about the causes and consequences of retroviral endogenization. This review highlights functions ascribed to sequences of viral origin endogenized into mammalian genomes and suggests some of the most pressing questions raised by these observations. PMID:27128186

  20. Pantropic retroviruses as a transduction tool for sea urchin embryos.

    PubMed

    Core, Amanda B; Reyna, Arlene E; Conaway, Evan A; Bradham, Cynthia A

    2012-04-01

    Sea urchins are an important model for experiments at the intersection of development and systems biology, and technical innovations that enhance the utility of this model are of great value. This study explores pantropic retroviruses as a transduction tool for sea urchin embryos, and demonstrates that pantropic retroviruses infect sea urchin embryos with high efficiency and genomically integrate at a copy number of one per cell. We successfully used a self-inactivation strategy to both insert a sea urchin-specific enhancer and disrupt the endogenous viral enhancer. The resulting self-inactivating viruses drive global and persistent gene expression, consistent with genomic integration during the first cell cycle. Together, these data provide substantial proof of principle for transduction technology in sea urchin embryos. PMID:22431628

  1. Lack of Detection of Human Retrovirus-5 Proviral DNA in Synovial Tissue and Blood Specimens From Individuals With Rheumatoid Arthritis or Osteoarthritis

    PubMed Central

    PIPER, KERRYL E.; HANSSEN, ARLEN D.; LEWALLEN, DAVID G.; MATTESON, ERIC L.; OSMON, DOUGLAS R.; DUFFY, MARY C.; HAGAN, ROCHELLE A.; STECKELBERG, JAMES M.; PATEL, ROBIN

    2006-01-01

    Objective Prior studies have suggested an association of human retrovirus 5 with rheumatoid arthritis. The purpose of this study was to determine if human retrovirus-5 proviral DNA is present in synovial tissue and blood specimens from patients with rheumatoid arthritis or osteoarthritis, or those without joint disease. Methods Synovial tissue and whole blood from 75 patients with rheumatoid arthritis, 75 patients with osteoarthritis, and 50 patients without a primary arthritis diagnosis were assayed by real-time quantitative polymerase chain reaction (PCR) using primers that amplify a 186-bp fragment of human retrovirus-5 proviral DNA. Results A total of 200 tissue specimens, 200 mononuclear cells, and 196 of 200 granulocyte specimens tested negative for human retrovirus-5 proviral DNA. No association between human retrovirus 5 and rheumatoid arthritis or osteoarthritis (P = 0.516) was identified. Granulocyte specimens from 4 patients, 2 with rheumatoid arthritis and 2 with osteoarthritis, yielded a low positive human retrovirus-5 proviral DNA signal (83–1,365 copies of human retrovirus-5 proviral DNA/ml blood). Conclusion Contrary to prior reports, we did not find an association between human retrovirus 5 and rheumatoid arthritis or osteoarthritis using a real-time PCR assay. Our findings are consistent with the recent finding that human retrovirus 5 is actually rabbit endogenous retrovirus H. PMID:16463423

  2. Self-deleting retrovirus vectors for gene therapy.

    PubMed Central

    Russ, A P; Friedel, C; Grez, M; von Melchner, H

    1996-01-01

    A new generation of retrovirus vectors for gene therapy has been developed. The vectors have the ability to excise themselves after inserting a gene into the genome, thereby avoiding problems encountered with conventional retrovirus vectors, such as recombination with helper viruses or transcriptional repression of transduced genes. The strategy exploited (i) the natural life cycle of retroviruses, involving duplication of terminal control regions U5 and U3 to generate long terminal repeats (LTRs) and (ii) the ability of the P1 phage site-specific recombinase (Cre) to excise any sequences positioned between two loxP target sequences from the mammalian genome. Thus, an independently expressed selectable marker gene flanked by a loxP target sequence was cloned into the U3 region of a Moloney murine leukemia virus vector. A separate cassette expressing the Cre recombinase was inserted between the LTRs into the body of the virus. LTR-mediated duplication placed vector sequences, including Cre, between loxP sites in the integrated provirus. This enabled Cre to excise from the provirus most of the viral and nonviral sequences unrelated to transcription of the U3 gene. PMID:8763996

  3. Human retroviruses and AIDS 1994

    SciTech Connect

    Myers, G.; Korber, B.; Wain-Hobson, S.; Jeang, Kuan-Teh; Henderson, L.E.; Pavlakis, G.N.

    1995-01-01

    This compendium, including accompanying floppy diskettes, is the result of an effort to compile and rapidly publish all relevant molecular data concerning the human immunodeficiency viruses (HIV) and related retroviruses. The scope of the compendium and database is best summarized by the five parts it comprises: (I) Nucleic Acid Alignments and Sequences; (II) Amino Acid Alignments; (III) Analysis; (IV) Related Sequences; (V) Database communications.

  4. Multifunctional facets of retrovirus integrase

    PubMed Central

    Grandgenett, Duane P; Pandey, Krishan K; Bera, Sibes; Aihara, Hideki

    2015-01-01

    The retrovirus integrase (IN) is responsible for integration of the reverse transcribed linear cDNA into the host DNA genome. First, IN cleaves a dinucleotide from the 3’ OH blunt ends of the viral DNA exposing the highly conserved CA sequence in the recessed ends. IN utilizes the 3’ OH ends to catalyze the concerted integration of the two ends into opposite strands of the cellular DNA producing 4 to 6 bp staggered insertions, depending on the retrovirus species. The staggered ends are repaired by host cell machinery that results in a permanent copy of the viral DNA in the cellular genome. Besides integration, IN performs other functions in the replication cycle of several studied retroviruses. The proper organization of IN within the viral internal core is essential for the correct maturation of the virus. IN plays a major role in reverse transcription by interacting directly with the reverse transcriptase and by binding to the viral capsid protein and a cellular protein. Recruitment of several other host proteins into the viral particle are also promoted by IN. IN assists with the nuclear transport of the preintegration complex across the nuclear membrane. With several retroviruses, IN specifically interacts with different host protein factors that guide the preintegration complex to preferentially integrate the viral genome into specific regions of the host chromosomal target. Human gene therapy using retrovirus vectors is directly affected by the interactions of IN with these host factors. Inhibitors directed against the human immunodeficiency virus (HIV) IN bind within the active site of IN containing viral DNA ends thus preventing integration and subsequent HIV/AIDS. PMID:26322168

  5. Multifunctional facets of retrovirus integrase.

    PubMed

    Grandgenett, Duane P; Pandey, Krishan K; Bera, Sibes; Aihara, Hideki

    2015-08-26

    The retrovirus integrase (IN) is responsible for integration of the reverse transcribed linear cDNA into the host DNA genome. First, IN cleaves a dinucleotide from the 3' OH blunt ends of the viral DNA exposing the highly conserved CA sequence in the recessed ends. IN utilizes the 3' OH ends to catalyze the concerted integration of the two ends into opposite strands of the cellular DNA producing 4 to 6 bp staggered insertions, depending on the retrovirus species. The staggered ends are repaired by host cell machinery that results in a permanent copy of the viral DNA in the cellular genome. Besides integration, IN performs other functions in the replication cycle of several studied retroviruses. The proper organization of IN within the viral internal core is essential for the correct maturation of the virus. IN plays a major role in reverse transcription by interacting directly with the reverse transcriptase and by binding to the viral capsid protein and a cellular protein. Recruitment of several other host proteins into the viral particle are also promoted by IN. IN assists with the nuclear transport of the preintegration complex across the nuclear membrane. With several retroviruses, IN specifically interacts with different host protein factors that guide the preintegration complex to preferentially integrate the viral genome into specific regions of the host chromosomal target. Human gene therapy using retrovirus vectors is directly affected by the interactions of IN with these host factors. Inhibitors directed against the human immunodeficiency virus (HIV) IN bind within the active site of IN containing viral DNA ends thus preventing integration and subsequent HIV/AIDS. PMID:26322168

  6. Revisiting a role for a mammary tumor retrovirus in human breast cancer.

    PubMed

    Salmons, Brian; Gunzburg, Walter H

    2013-10-01

    There remains great controversy as to whether mouse mammary tumor virus (MMTV), the etiological agent of mammary cancer in mice, or a closely related human retrovirus, plays a role in the development of breast cancer in humans. On one hand, retroviruses such as human T-cell lymphotropic virus and human immunodeficiency virus (HIV) are known causative agents of cancer (in the case of HIV, albeit, indirectly), but attempts to associate other retroviruses with human cancers have been difficult. A recent, high profile, example has been the postulated involvement of another mouse virus, xenotropic murine leukemia virus-related virus, in human prostate cancer, which is now thought to be due to contamination. Here, we review some of the more recent evidence for and against the involvement of MMTV in human breast cancer and suggest future studies that may allow a definitive answer to this conundrum. PMID:23580334

  7. Review of the twelfth West Coast retrovirus meeting

    PubMed Central

    Barry, Sheila M; Melar, Marta; Gallay, Philippe; Hope, Thomas J

    2005-01-01

    Every year the Cancer Research Institute from University of California at Irvine organizes the West Coast Retrovirus Meeting where participants have a chance to discuss the latest progress in understanding the pathology of retroviruses. The 12th meeting was held at the Hyatt Regency Suites in Palm Springs, California from October 6th to October 9th 2005, with the major focus on human immunodeficiency virus (HIV) pathogenesis. Philippe Gallay from The Scripps Research Institute and Thomas J. Hope from Northwestern University organized the meeting, which covered all the steps involved in the lifecycle of retroviruses with an emphasis on virus:host interactions. The trend in research appeared to be on the restriction of viral infection, both by the endogenous, cellular restriction factors, as well as by the potential antimicrobial compounds of known or unknown mechanisms. Additionally, new stories on the inevitable feedback from the host immune system were presented as well. HIV still represents a challenge that an army of motivated people has been working on for over 20 years. And yet, the field has not reached the plateau in knowledge nor enthusiasm, which was proven again in October 2005 in Palm Springs. PMID:16293194

  8. Recombinant Origin of the Retrovirus XMRV

    PubMed Central

    Paprotka, Tobias; Delviks-Frankenberry, Krista A.; Cingöz, Oya; Martinez, Anthony; Kung, Hsing-Jien; Tepper, Clifford G.; Hu, Wei-Shau; Fivash, Matthew J.; Coffin, John M.; Pathak, Vinay K.

    2012-01-01

    The retrovirus XMRV (xenotropic murine leukemia virus-related virus) has been detected in human prostate tumors and in blood samples from patients with chronic fatigue syndrome, but these findings have not been replicated. We hypothesized that an understanding of when and how XMRV first arose might help explain the discrepant results. We studied human prostate cancer cell lines CWR22Rv1 and CWR-R1, which produce XMRV virtually identical to the viruses recently found in patient samples, as well as their progenitor human prostate tumor xenograft (CWR22) that had been passaged in mice. We detected XMRV infection in the two cell lines and in the later passage xenografts, but not in the early passages. Importantly, we found that the host mice contained two proviruses, PreXMRV-1 and PreXMRV-2, which share 99.92% identity with XMRV over >3.2-kb stretches of their genomes. We conclude that XMRV was not present in the original CWR22 tumor but was generated by recombination of two proviruses during tumor passaging in mice. The probability that an identical recombinant was generated independently is negligible (~10-12); our results suggest that the association of XMRV with human disease is due to contamination of human samples with virus originating from this recombination event. PMID:21628392

  9. Effects of chronic methamphetamine exposure on heart function in uninfected and retrovirus-infected mice.

    PubMed

    Yu, Qianli; Montes, Sergio; Larson, Douglas F; Watson, Ronald R

    2002-07-12

    Methamphetamine (MA) increases catecholamine levels, which have detrimental effects on heart function through vasoconstriction, myocardial hypertrophy, and fibrosis. Murine retrovirus infection induces dilated cardiomyopathy (DCM). The present study investigated the cardiovascular effects of chronic MA treatment on uninfected and retrovirus-infected mice. C57BL/6 mice were studied after 12 weeks treatment. The four study groups were (group I) uninfected, MA placebo; (group II) infected, MA placebo; (group III) uninfected, MA treatment; and (group IV) infected and MA treatment. MA injections were given i.p. once a day for 5 days/week with a increasing dose from 15 mg/kg to 40 mg/kg. Left ventricular mechanics were measured in situ a using Millar conductance catheter system for pressure-volume loop analysis. Cardiac pathology was determined with histological analysis. In the uninfected mice, the load independent contractile parameters, pre-load recruitable stroke work (PRSW) and dP/dt(max) vs. Ved, significantly decreased by 32% and 35% in MA treated mice when compared to the saline injected mice. In retrovirus-infected mice, although there were no significant difference in Ees, PRSW, and dP/dt(max) vs. Ved due to MA treatment, they were increased 45%, 15% and 42% respectively when compared to saline treated mice. No further lowered heart function during murine AIDS may be due to the counteraction of the retroviral DCM and the MA induced myocardial fibrosis and hypertrophy (thickening of the ventricular walls). This is supported by increases in the End-diastolic volume (Ved, 38%) and End-systolic volume (Ves, 84%) in the retrovirus-infected saline injected mice, the decreases of 33% and 17% in the uninfected MA-treated mice, but no significant changes in the retrovirus-infected MA treated mice when compared to uninfected saline injected mice. These data suggest that MA induced myocardial cellular changes compensate for retrovirus induced DCM. PMID:12084392

  10. HERVd: the Human Endogenous RetroViruses Database: update.

    PubMed

    Paces, Jan; Pavlícek, Adam; Zika, Radek; Kapitonov, Vladimir V; Jurka, Jerzy; Paces, Václav

    2004-01-01

    An elaboration of HERVd (http://herv.img.cas.cz) is being carried out in two directions. One of them is the integration and better classification of families that diverge considerably from typical retroviral genomes. This leads to a more precise identification of members with individual families. The second improvement is better accessibility of the database and connection with human genome annotation. PMID:14681356

  11. A novel approach to achieving modular retrovirus clearance for a parvovirus filter.

    PubMed

    Stuckey, Juliana; Strauss, Daniel; Venkiteshwaran, Adith; Gao, Jinxin; Luo, Wen; Quertinmont, Michelle; O'Donnell, Sean; Chen, Dayue

    2014-01-01

    Viral filtration is routinely incorporated into the downstream purification processes for the production of biologics produced in mammalian cell cultures (MCC) to remove potential viral contaminants. In recent years, the use of retentive filters designed for retaining parvovirus (~20 nm) has become an industry standard in a conscious effort to further improve product safety. Since retentive filters remove viruses primarily by the size exclusion mechanism, it is expected that filters designed for parvovirus removal can effectively clear larger viruses such as retroviruses (~100 nm). In an attempt to reduce the number of viral clearance studies, we have taken a novel approach to demonstrate the feasibility of claiming modular retrovirus clearance for Asahi Planova 20N filters. Porcine parvovirus (PPV) and xenotropic murine leukemia virus (XMuLV) were co-spiked into six different feedstreams and then subjected to laboratory scale Planova 20N filtration. Our results indicate that Planova 20N filters consistently retain retroviruses and no retrovirus has ever been detected in the filtrates even when significant PPV breakthrough is observed. Based on the data from multiple in-house viral validation studies and the results from the co-spiking experiments, we have successfully claimed a modular retrovirus clearance of greater than 6 log10 reduction factors (LRF) to support clinical trial applications in both USA and Europe. PMID:24123923

  12. Retrovirus Vectors Bearing Jaagsiekte Sheep Retrovirus Env Transduce Human Cells by Using a New Receptor Localized to Chromosome 3p21.3

    PubMed Central

    Rai, Sharath K.; DeMartini, James C.; Miller, A. Dusty

    2000-01-01

    Jaagsiekte sheep retrovirus (JSRV) is a type D retrovirus associated with a contagious lung tumor of sheep, ovine pulmonary carcinoma. Other than sheep, JSRV is known to infect goats, but there is no evidence of human infection. Until now it has not been possible to study the host range for JSRV because of the inability to grow this virus in culture. Here we show that the JSRV envelope protein (Env) can be used to pseudotype Moloney murine leukemia virus (MoMLV)-based retrovirus vectors and that such vectors can transduce human cells in culture. We constructed hybrid retrovirus packaging cells that express the JSRV Env and the MoMLV Gag-Pol proteins and can produce JSRV-pseudotype vectors at titers of up to 106 alkaline phosphatase-positive focus-forming units/ml. Using this high-titer virus, we have studied the host range for JSRV, which includes sheep, human, monkey, bovine, dog, and rabbit cells but not mouse, rat, or hamster cells. Considering the inability of the JSRV-pseudotype vector to transduce hamster cells, we used the hamster cell line-based Stanford G3 panel of whole human genome radiation hybrids to phenotypically map the JSRV receptor (JVR) gene within the p21.3 region of human chromosome 3. JVR is likely a new retrovirus receptor, as none of the previously identified retrovirus receptors localizes to the same position. Several chemokine receptors that have been shown to serve as coreceptors for lentivirus infection are clustered in the same region of chromosome 3; however, careful examination shows that the JSRV receptor does not colocalize with any of these genes. PMID:10775607

  13. Harnessing endogenous miR-181a to segregate transgenic antigen receptor expression in developing versus post-thymic T cells in murine hematopoietic chimeras.

    PubMed

    Papapetrou, Eirini P; Kovalovsky, Damian; Beloeil, Laurent; Sant'angelo, Derek; Sadelain, Michel

    2009-01-01

    MicroRNAs (miRNAs) are small, noncoding RNAs that regulate gene expression by targeting complementary sequences, referred to as miRNA recognition elements (MREs), typically located in the 3' untranslated region of mRNAs. miR-181a is highly expressed in developing thymocytes and markedly downregulated in post-thymic T cells. We investigated whether endogenous miR-181a can be harnessed to segregate expression of chimeric antigen receptors (CARs) and TCRs between developing and mature T cells. Lentiviral-encoded antigen receptors were tagged with a miR-181a-specific MRE and transduced into mouse BM cells that were used to generate hematopoietic chimeras. Expression of a CAR specific for human CD19 (hCD19) was selectively suppressed in late double-negative and double-positive thymocytes, coinciding with the peak in endogenous miR-181a expression. Receptor expression was fully restored in post-thymic resting and activated T cells, affording protection against a subsequent challenge with hCD19+ tumors. Hematopoietic mouse chimeras engrafted with a conalbumin-specific TCR prone to thymic clonal deletion acquired peptide-specific T cell responsiveness only when the vector-encoded TCR transcript was similarly engineered to be subject to regulation by miR-181a. These results demonstrate the potential of miRNA-regulated transgene expression in stem cell-based therapies, including cancer immunotherapy. PMID:19033646

  14. Activation of endogenous p53 by combined p19Arf gene transfer and nutlin-3 drug treatment modalities in the murine cell lines B16 and C6

    PubMed Central

    2010-01-01

    Background Reactivation of p53 by either gene transfer or pharmacologic approaches may compensate for loss of p19Arf or excess mdm2 expression, common events in melanoma and glioma. In our previous work, we constructed the pCLPG retroviral vector where transgene expression is controlled by p53 through a p53-responsive promoter. The use of this vector to introduce p19Arf into tumor cells that harbor p53wt should yield viral expression of p19Arf which, in turn, would activate the endogenous p53 and result in enhanced vector expression and tumor suppression. Since nutlin-3 can activate p53 by blocking its interaction with mdm2, we explored the possibility that the combination of p19Arf gene transfer and nutlin-3 drug treatment may provide an additive benefit in stimulating p53 function. Methods B16 (mouse melanoma) and C6 (rat glioma) cell lines, which harbor p53wt, were transduced with pCLPGp19 and these were additionally treated with nutlin-3 or the DNA damaging agent, doxorubicin. Viral expression was confirmed by Western, Northern and immunofluorescence assays. p53 function was assessed by reporter gene activity provided by a p53-responsive construct. Alterations in proliferation and viability were measured by colony formation, growth curve, cell cycle and MTT assays. In an animal model, B16 cells were treated with the pCLPGp19 virus and/or drugs before subcutaneous injection in C57BL/6 mice, observation of tumor progression and histopathologic analyses. Results Here we show that the functional activation of endogenous p53wt in B16 was particularly challenging, but accomplished when combined gene transfer and drug treatments were applied, resulting in increased transactivation by p53, marked cell cycle alteration and reduced viability in culture. In an animal model, B16 cells treated with both p19Arf and nutlin-3 yielded increased necrosis and decreased BrdU marking. In comparison, C6 cells were quite susceptible to either treatment, yet p53 was further activated

  15. Negative regulatory element associated with potentially functional promoter and enhancer elements in the long terminal repeats of endogenous murine leukemia virus-related proviral sequences.

    PubMed Central

    Ch'ang, L Y; Yang, W K; Myer, F E; Yang, D M

    1989-01-01

    Three series of recombinant DNA clones were constructed, with the bacterial chloramphenicol acetyltransferase (CAT) gene as a quantitative indicator, to examine the activities of promoter and enhancer sequence elements in the 5' long terminal repeat (LTR) of murine leukemia virus (MuLV)-related proviral sequences isolated from the mouse genome. Transient CAT expression was determined in mouse NIH 3T3, human HT1080, and mink CCL64 cultured cells transfected with the LTR-CAT constructs. The 700-base-pair (bp) LTRs of three polytropic MuLV-related proviral clones and the 750-bp LTRs of four modified polytropic proviral clones, in complete structures either with or without the adjacent downstream sequences, all showed very little or negligible activities for CAT expression, while ecotropic MuLV LTRs were highly active. The MuLV-related LTRs were divided into three portions and examined separately. The 3' portion of the MuLV-related LTRs that contains the CCAAC and TATAA boxes was found to be a functional promoter, being about one-half to one-third as active as the corresponding portion of ecotropic MuLV LTRs. A MboI-Bg/II fragment, representing the distinct 190- to 200-bp inserted segment in the middle, was found to be a potential enhancer, especially when examined in combination with the simian virus 40 promoter in CCL64 cells. A PstI-MboI fragment of the 5' portion, which contains the protein-binding motifs of the enhancer segment as well as the upstream LTR sequences, showed moderate enhancer activities in CCL6 cells but was virtually inactive in NIH 3T3 cells and HT1080 cells; addition of this fragment to the ecotropic LTR-CAT constructs depressed CAT expression. Further analyses using chimeric LTR constructs located the presence of a strong negative regulatory element within the region containing the 5' portion of the enhancer and the immediate upstream sequences in the MuLV-related LTRs. Images PMID:2542587

  16. Revealing the history of sheep domestication using retrovirus integrations.

    PubMed

    Chessa, Bernardo; Pereira, Filipe; Arnaud, Frederick; Amorim, Antonio; Goyache, Félix; Mainland, Ingrid; Kao, Rowland R; Pemberton, Josephine M; Beraldi, Dario; Stear, Michael J; Alberti, Alberto; Pittau, Marco; Iannuzzi, Leopoldo; Banabazi, Mohammad H; Kazwala, Rudovick R; Zhang, Ya-Ping; Arranz, Juan J; Ali, Bahy A; Wang, Zhiliang; Uzun, Metehan; Dione, Michel M; Olsaker, Ingrid; Holm, Lars-Erik; Saarma, Urmas; Ahmad, Sohail; Marzanov, Nurbiy; Eythorsdottir, Emma; Holland, Martin J; Ajmone-Marsan, Paolo; Bruford, Michael W; Kantanen, Juha; Spencer, Thomas E; Palmarini, Massimo

    2009-04-24

    The domestication of livestock represented a crucial step in human history. By using endogenous retroviruses as genetic markers, we found that sheep differentiated on the basis of their "retrotype" and morphological traits dispersed across Eurasia and Africa via separate migratory episodes. Relicts of the first migrations include the Mouflon, as well as breeds previously recognized as "primitive" on the basis of their morphology, such as the Orkney, Soay, and the Nordic short-tailed sheep now confined to the periphery of northwest Europe. A later migratory episode, involving sheep with improved production traits, shaped the great majority of present-day breeds. The ability to differentiate genetically primitive sheep from more modern breeds provides valuable insights into the history of sheep domestication. PMID:19390051

  17. Transcription termination and polyadenylation in retroviruses.

    PubMed

    Guntaka, R V

    1993-09-01

    The provirus structure of retroviruses is bracketed by long terminal repeats (LTRs). The two LTRs (5' and 3') are identical in nucleotide sequence and organization. They contain signals for transcription initiation as well as termination and cleavage polyadenylation. As in eukaryotic pre-mRNAs, the two common signals, the polyadenylation signal, AAUAAA, or a variant AGUAAA, and the G+U-rich sequence are present in all retroviruses. However, the AAUAAA sequence is present in the U3 region in some retroviruses and in the R region in other retroviruses. As in animal cell RNAs, both AAUAAA and G+U-rich sequences apparently contribute to the 3'-end processing of retroviral RNAs. In addition, at least in a few cases examined, the sequences in the U3 region determine the efficiency of 3'-end processing. In retroviruses in which the AAUAAA is localized in the R region, the poly(A) signal in the 3' LTR but not the 5' LTR must be selectively used for the production of genomic RNA. It appears that the short distance between the 5' cap site and polyadenylation signal in the 5' LTR precludes premature termination and polyadenylation. Since 5' and 3' LTRs are identical in sequence and structural organization yet function differently, it is speculated that flanking cellular DNA sequences, chromatin structure, and binding of transcription factors may be involved in the functional divergence of 5' and 3' LTRs of retroviruses. PMID:7902524

  18. Retroviruses use CD169-mediated trans-infection of permissive lymphocytes to establish infection

    PubMed Central

    Sewald, Xaver; Beloor, Jagadish; Pi, Ruoxi; Herrmann, Christin; Motamedi, Nasim; Murooka, Thomas T.; Brehm, Michael A.; Greiner, Dale L.; Shultz, Leonard D.; Mempel, Thorsten R.; Bjorkman, Pamela J.; Kumar, Priti; Mothes, Walther

    2015-01-01

    Dendritic cells can capture and transfer retroviruses in vitro across synaptic cell-cell contacts to uninfected cells, a process called trans-infection. Whether trans-infection contributes to retroviral spread in vivo remains unknown. Here, we visualize how retroviruses disseminate in secondary lymphoid tissues of living mice. We demonstrate that murine leukemia virus (MLV) and human immunodeficiency virus (HIV) are first captured by sinus-lining macrophages. CD169/Siglec-1, an I-type lectin that recognizes gangliosides, captures the virus. MLV-laden macrophages then form long-lived synaptic contacts to trans-infect B-1 cells. Infected B-1 cells subsequently migrate into the lymph node to spread the infection through virological synapses. Robust infection in lymph nodes and spleen requires CD169, suggesting that a combination of fluid-based movement followed by CD169-dependent trans-infection can contribute to viral spread. PMID:26429886

  19. Gamma-Retrovirus Integration Marks Cell Type-Specific Cancer Genes: A Novel Profiling Tool in Cancer Genomics

    PubMed Central

    Gilroy, Kathryn L.; Terry, Anne; Naseer, Asif; de Ridder, Jeroen; Wang, Weiwei; Carpenter, Eric; Mason, Andrew; Wong, Gane K-S.; Kilbey, Anna; Neil, James C.

    2016-01-01

    Retroviruses have been foundational in cancer research since early studies identified proto-oncogenes as targets for insertional mutagenesis. Integration of murine gamma-retroviruses into the host genome favours promoters and enhancers and entails interaction of viral integrase with host BET/bromodomain factors. We report that this integration pattern is conserved in feline leukaemia virus (FeLV), a gamma-retrovirus that infects many human cell types. Analysis of FeLV insertion sites in the MCF-7 mammary carcinoma cell line revealed strong bias towards active chromatin marks with no evidence of significant post-integration growth selection. The most prominent FeLV integration targets had little overlap with the most abundantly expressed transcripts, but were strongly enriched for annotated cancer genes. A meta-analysis based on several gamma-retrovirus integration profiling (GRIP) studies in human cells (CD34+, K562, HepG2) revealed a similar cancer gene bias but also remarkable cell-type specificity, with prominent exceptions including a universal integration hotspot at the long non-coding RNA MALAT1. Comparison of GRIP targets with databases of super-enhancers from the same cell lines showed that these have only limited overlap and that GRIP provides unique insights into the upstream drivers of cell growth. These observations elucidate the oncogenic potency of the gamma-retroviruses and support the wider application of GRIP to identify the genes and growth regulatory circuits that drive distinct cancer types. PMID:27097319

  20. Gamma-Retrovirus Integration Marks Cell Type-Specific Cancer Genes: A Novel Profiling Tool in Cancer Genomics.

    PubMed

    Gilroy, Kathryn L; Terry, Anne; Naseer, Asif; de Ridder, Jeroen; Allahyar, Amin; Wang, Weiwei; Carpenter, Eric; Mason, Andrew; Wong, Gane K-S; Cameron, Ewan R; Kilbey, Anna; Neil, James C

    2016-01-01

    Retroviruses have been foundational in cancer research since early studies identified proto-oncogenes as targets for insertional mutagenesis. Integration of murine gamma-retroviruses into the host genome favours promoters and enhancers and entails interaction of viral integrase with host BET/bromodomain factors. We report that this integration pattern is conserved in feline leukaemia virus (FeLV), a gamma-retrovirus that infects many human cell types. Analysis of FeLV insertion sites in the MCF-7 mammary carcinoma cell line revealed strong bias towards active chromatin marks with no evidence of significant post-integration growth selection. The most prominent FeLV integration targets had little overlap with the most abundantly expressed transcripts, but were strongly enriched for annotated cancer genes. A meta-analysis based on several gamma-retrovirus integration profiling (GRIP) studies in human cells (CD34+, K562, HepG2) revealed a similar cancer gene bias but also remarkable cell-type specificity, with prominent exceptions including a universal integration hotspot at the long non-coding RNA MALAT1. Comparison of GRIP targets with databases of super-enhancers from the same cell lines showed that these have only limited overlap and that GRIP provides unique insights into the upstream drivers of cell growth. These observations elucidate the oncogenic potency of the gamma-retroviruses and support the wider application of GRIP to identify the genes and growth regulatory circuits that drive distinct cancer types. PMID:27097319

  1. Gene transfer into experimental brain tumors mediated by adenovirus, herpes simplex virus, and retrovirus vectors.

    PubMed

    Boviatsis, E J; Chase, M; Wei, M X; Tamiya, T; Hurford, R K; Kowall, N W; Tepper, R I; Breakefield, X O; Chiocca, E A

    1994-02-01

    Three vectors derived from retrovirus, herpes simplex virus type 1 (HSV), and adenovirus were compared in cultured rat 9L gliosarcoma cells for gene transfer efficiency and in a 9L rat brain tumor model for histologic pattern and distribution of foreign gene delivery, as well as for associated tumor necrosis and inflammation. At a multiplicity of infection of 1, in vitro transfer of a foreign gene (lacZ from Escherichia coli) into cells was more efficient with either the replication-defective retrovirus vector or the replication-conditional thymidine kinase (TK)-deficient HSV vector than with the replication-defective adenovirus vector. In vivo, stereotactic injections of each vector into rat brain tumors revealed three main histopathologic findings: (i) retrovirus and HSV vector-mediated gene transfer was relatively selective for cells within the tumor, whereas adenovirus vector-mediated gene transfer occurred into several types of endogenous neural cells, as well as into cells within the tumor; (ii) gene transfer to multiple infiltrating tumor deposits without apparent gene transfer to intervening normal brain tissue occurred uniquely in one animal inoculated with the HSV vector, and (iii) extensive necrosis and selective inflammation in the tumor were evident with the HSV vector, whereas there was minimal evidence of tumor necrosis and inflammation with either the retrovirus or adenovirus vectors. PMID:8186298

  2. DMXAA causes tumor site-specific vascular disruption in murine non-small cell lung cancer, and like the endogenous non-canonical cyclic dinucleotide STING agonist, 2'3'-cGAMP, induces M2 macrophage repolarization.

    PubMed

    Downey, Charlene M; Aghaei, Mehrnoosh; Schwendener, Reto A; Jirik, Frank R

    2014-01-01

    The vascular disrupting agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a murine agonist of the stimulator of interferon genes (STING), appears to target the tumor vasculature primarily as a result of stimulating pro-inflammatory cytokine production from tumor-associated macrophages (TAMs). Since there were relatively few reports of DMXAA effects in genetically-engineered mutant mice (GEMM), and models of non-small cell lung cancer (NSCLC) in particular, we examined both the effectiveness and macrophage dependence of DMXAA in various NSCLC models. The DMXAA responses of primary adenocarcinomas in K-rasLA1/+ transgenic mice, as well as syngeneic subcutaneous and metastatic tumors, generated by a p53R172HΔg/+; K-rasLA1/+ NSCLC line (344SQ-ELuc), were assessed both by in vivo bioluminescence imaging as well as by histopathology. Macrophage-dependence of DMXAA effects was explored by clodronate liposome-mediated TAM depletion. Furthermore, a comparison of the vascular structure between subcutaneous tumors and metastases was carried out using micro-computed tomography (micro-CT). Interestingly, in contrast to the characteristic hemorrhagic necrosis produced by DMXAA in 344SQ-ELuc subcutaneous tumors, this agent failed to cause hemorrhagic necrosis of either 344SQ-ELuc-derived metastases or autochthonous K-rasLA1/+ NSCLCs. In addition, we found that clodronate liposome-mediated depletion of TAMs in 344SQ-ELuc subcutaneous tumors led to non-hemorrhagic necrosis due to tumor feeding-vessel occlusion. Since NSCLC were comprised exclusively of TAMs with anti-inflammatory M2-like phenotype, the ability of DMXAA to re-educate M2-polarized macrophages was examined. Using various macrophage phenotypic markers, we found that the STING agonists, DMXAA and the non-canonical endogenous cyclic dinucleotide, 2'3'-cGAMP, were both capable of re-educating M2 cells towards an M1 phenotype. Our findings demonstrate that the choice of preclinical model and the anatomical site of a

  3. DMXAA Causes Tumor Site-Specific Vascular Disruption in Murine Non-Small Cell Lung Cancer, and like the Endogenous Non-Canonical Cyclic Dinucleotide STING Agonist, 2′3′-cGAMP, Induces M2 Macrophage Repolarization

    PubMed Central

    Downey, Charlene M.; Aghaei, Mehrnoosh; Schwendener, Reto A.; Jirik, Frank R.

    2014-01-01

    The vascular disrupting agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a murine agonist of the stimulator of interferon genes (STING), appears to target the tumor vasculature primarily as a result of stimulating pro-inflammatory cytokine production from tumor-associated macrophages (TAMs). Since there were relatively few reports of DMXAA effects in genetically-engineered mutant mice (GEMM), and models of non-small cell lung cancer (NSCLC) in particular, we examined both the effectiveness and macrophage dependence of DMXAA in various NSCLC models. The DMXAA responses of primary adenocarcinomas in K-rasLA1/+ transgenic mice, as well as syngeneic subcutaneous and metastatic tumors, generated by a p53R172HΔg/+; K-rasLA1/+ NSCLC line (344SQ-ELuc), were assessed both by in vivo bioluminescence imaging as well as by histopathology. Macrophage-dependence of DMXAA effects was explored by clodronate liposome-mediated TAM depletion. Furthermore, a comparison of the vascular structure between subcutaneous tumors and metastases was carried out using micro-computed tomography (micro-CT). Interestingly, in contrast to the characteristic hemorrhagic necrosis produced by DMXAA in 344SQ-ELuc subcutaneous tumors, this agent failed to cause hemorrhagic necrosis of either 344SQ-ELuc-derived metastases or autochthonous K-rasLA1/+ NSCLCs. In addition, we found that clodronate liposome-mediated depletion of TAMs in 344SQ-ELuc subcutaneous tumors led to non-hemorrhagic necrosis due to tumor feeding-vessel occlusion. Since NSCLC were comprised exclusively of TAMs with anti-inflammatory M2-like phenotype, the ability of DMXAA to re-educate M2-polarized macrophages was examined. Using various macrophage phenotypic markers, we found that the STING agonists, DMXAA and the non-canonical endogenous cyclic dinucleotide, 2′3′-cGAMP, were both capable of re-educating M2 cells towards an M1 phenotype. Our findings demonstrate that the choice of preclinical model and the anatomical site of a

  4. Morphology and ultrastructure of retrovirus particles

    PubMed Central

    Zhang, Wei; Cao, Sheng; Martin, Jessica L.; Mueller, Joachim D.; Mansky, Louis M.

    2015-01-01

    Retrovirus morphogenesis entails assembly of Gag proteins and the viral genome on the host plasma membrane, acquisition of the viral membrane and envelope proteins through budding, and formation of the core through the maturation process. Although in both immature and mature retroviruses, Gag and capsid proteins are organized as paracrystalline structures, the curvatures of these protein arrays are evidently not uniform within one or among all virus particles. The heterogeneity of retroviruses poses significant challenges to studying the protein contacts within the Gag and capsid lattices. This review focuses on current understanding of the molecular organization of retroviruses derived from the sub-nanometer structures of immature virus particles, helical capsid protein assemblies and soluble envelope protein complexes. These studies provide insight into the molecular elements that maintain the stability, flexibility and infectivity of virus particles. Also reviewed are morphological studies of retrovirus budding, maturation, infection and cell-cell transmission, which inform the structural transformation of the viruses and the cells during infection and viral transmission, and lead to better understanding of the interplay between the functioning viral proteins and the host cell. PMID:26448965

  5. Human RNA “Rumor” Viruses: the Search for Novel Human Retroviruses in Chronic Disease

    PubMed Central

    Voisset, Cécile; Weiss, Robin A.; Griffiths, David J.

    2008-01-01

    Summary: Retroviruses are an important group of pathogens that cause a variety of diseases in humans and animals. Four human retroviruses are currently known, including human immunodeficiency virus type 1, which causes AIDS, and human T-lymphotropic virus type 1, which causes cancer and inflammatory disease. For many years, there have been sporadic reports of additional human retroviral infections, particularly in cancer and other chronic diseases. Unfortunately, many of these putative viruses remain unproven and controversial, and some retrovirologists have dismissed them as merely “human rumor viruses.” Work in this field was last reviewed in depth in 1984, and since then, the molecular techniques available for identifying and characterizing retroviruses have improved enormously in sensitivity. The advent of PCR in particular has dramatically enhanced our ability to detect novel viral sequences in human tissues. However, DNA amplification techniques have also increased the potential for false-positive detection due to contamination. In addition, the presence of many families of human endogenous retroviruses (HERVs) within our DNA can obstruct attempts to identify and validate novel human retroviruses. Here, we aim to bring together the data on “novel” retroviral infections in humans by critically examining the evidence for those putative viruses that have been linked with disease and the likelihood that they represent genuine human infections. We provide a background to the field and a discussion of potential confounding factors along with some technical guidelines. In addition, some of the difficulties associated with obtaining formal proof of causation for common or ubiquitous agents such as HERVs are discussed. PMID:18322038

  6. Human retroviruses and AIDS 1997

    SciTech Connect

    Korber, B.; Foley, B.; Leitner, T.

    1997-12-01

    This compendium is the result of an effort to compile, organize, and rapidly publish as much relevant molecular data concerning the human immunodeficiency viruses (HIV) and related retroviruses as possible. The scope of the compendium and database is best summarized by the four parts that it comprises: (1) Nucleic Acid Alignments, (2) Amino Acid Alignments, (3) Reviews and Analyses, and (4) Related Sequences. Information within all the parts is updated throughout the year on the Web site, http://hiv-web.lanl.gov. This year we are not including floppy diskettes as the entire compendium is available both at our Web site and at our ftp site. If you need floppy diskettes please contact either Bette Korber (btk@t10.lanl.gov) or Kersti Rock (karm@t10.lanl.gov) by email or fax ((505) 665-4453). While this publication could take the form of a review or sequence monograph, it is not so conceived. Instead, the literature from which the database is derived has simply been summarized and some elementary computational analyses have been performed upon the data. Interpretation and commentary have been avoided insofar as possible so that the reader can form his or her own judgments concerning the complex information. The exception to this are reviews submitted by experts in areas deemed of particular and basic importance to research involving AIDS viral sequence information. These are included in Part III, and are contributed by scientists with particular expertise in the area of interest. In addition to the general descriptions below of the parts of the compendium, the user should read the individual introductions for each part.

  7. A novel endogenous betaretrovirus group characterized from polar bears (Ursus maritimus) and giant pandas (Ailuropoda melanoleuca).

    PubMed

    Mayer, Jens; Tsangaras, Kyriakos; Heeger, Felix; Avila-Arcos, María; Stenglein, Mark D; Chen, Wei; Sun, Wei; Mazzoni, Camila J; Osterrieder, Nikolaus; Greenwood, Alex D

    2013-08-15

    Transcriptome analysis of polar bears (Ursus maritimus) yielded sequences with highest similarity to the human endogenous retrovirus group HERV-K(HML-2). Further analysis of the polar bear draft genome identified an endogenous betaretrovirus group comprising 26 proviral copies and 231 solo LTRs. Molecular dating indicates the group originated before the divergence of bears from a common ancestor but is not present in all carnivores. Closely related sequences were identified in the giant panda (Ailuropoda melanoleuca) and characterized from its genome. We have designated the polar bear and giant panda sequences U. maritimus endogenous retrovirus (UmaERV) and A. melanoleuca endogenous retrovirus (AmeERV), respectively. Phylogenetic analysis demonstrated that the bear virus group is nested within the HERV-K supergroup among bovine and bat endogenous retroviruses suggesting a complex evolutionary history within the HERV-K group. All individual remnants of proviral sequences contain numerous frameshifts and stop codons and thus, the virus is likely non-infectious. PMID:23725819

  8. A novel endogenous betaretrovirus group characterized from polar bears (Ursus maritimus) and giant pandas (Ailuropoda melanoleuca)

    PubMed Central

    Mayer, Jens; Tsangaras, Kyriakos; Heeger, Felix; Ávila-Arcos, Maria; Stenglein, Mark D.; Chen, Wei; Sun, Wei; Mazzoni, Camila; Osterrieder, Nikolaus; Greenwood, Alex D.

    2013-01-01

    Transcriptome analysis of polar bears (Ursus maritimus) yielded sequences with highest similarity to the human endogenous retrovirus group HERV-K(HML-2). Further analysis of the polar bear draft genome identified an endogenous betaretrovirus group comprising 26 proviral copies and 231 solo LTRs. Molecular dating indicates the group originated before the divergence of bears from a common ancestor but is not present in all carnivores. Closely related sequences were identified in the giant panda (Ailuropoda melanoleuca) and characterized from its genome. We have designated the polar bear and giant panda sequences Ursus maritimus endogenous retrovirus (UmaERV) and Ailuropoda melanoleuca endogenous retrovirus (AmeERV), respectively. Phylogenetic analysis demonstrated that the bear virus group is nested within the HERV-K supergroup among bovine and bat endogenous retroviruses suggesting a complex evolutionary history within the HERV-K group. All individual remnants of proviral sequences contain numerous frameshifts and stop codons and thus, the virus is likely non-infectious. PMID:23725819

  9. Localization of the receptor gene for type D simian retroviruses on human chromosome 19.

    PubMed Central

    Sommerfelt, M A; Williams, B P; McKnight, A; Goodfellow, P N; Weiss, R A

    1990-01-01

    Simian retrovirus (SRV) serotypes 1 to 5 are exogenous type D viruses causing immune suppression in macaque monkeys. These viruses exhibit receptor interference with each other, with two endogenous type D viruses of the langur (PO-1-Lu) and squirrel monkey, and with two type C retroviruses, feline endogenous virus (RD114/CCC) and baboon endogenous virus (BaEV), indicating that each utilizes the same cell surface receptor (M. A. Sommerfelt and R. A. Weiss, Virology 176:58-69, 1990). Vesicular stomatitis virus pseudotype particles bearing envelope glycoproteins of RD114, BaEV, and the seven SRV strains were employed to detect receptors expressed in human-rodent somatic cell hybrids segregating human chromosomes. The only human chromosome common to all the susceptible hybrids was chromosome 19. By using hybrids retaining different fragments of chromosome 19, a provisional subchromosomal localization of the receptor gene was made to 19q13.1-13.2. Antibodies previously reported to be specific to a BaEV receptor (L. Thiry, J. Cogniaux-Leclerc, R. Olislager, S. Sprecher-Goldberger, and P. Burkens, J. Virol. 48:697-708, 1983) did not block BaEV, RD114, or SRV pseudotypes or syncytia. Antibodies to known surface markers determined by genes mapped to chromosome 19 did not block virus-receptor interaction. The identity of the receptor remains to be determined. PMID:2173788

  10. Genomic stability of murine leukemia viruses containing insertions at the Env-3' untranslated region boundary.

    PubMed

    Logg, C R; Logg, A; Tai, C K; Cannon, P M; Kasahara, N

    2001-08-01

    Retroviruses containing inserts of exogenous sequences frequently eliminate the inserted sequences upon spread in susceptible cells. We have constructed replication-competent murine leukemia virus (MLV) vectors containing internal ribosome entry site (IRES)-transgene cassettes at the env-3' untranslated region boundary in order to examine the effects of insert sequence and size on the loss of inserts during viral replication. A virus containing an insertion of 1.6 kb replicated with greatly attenuated kinetics relative to wild-type virus and lost the inserted sequences in a single infection cycle. In contrast, MLVs containing inserts of 1.15 to 1.30 kb replicated with kinetics only slightly attenuated compared to wild-type MLV and exhibited much greater stability, maintaining their genomic integrity over multiple serial infection cycles. Eventually, multiple species of deletion mutants were detected simultaneously in later infection cycles; once detected, these variants rapidly dominated the population and thereafter appeared to be maintained at a relative equilibrium. Sequence analysis of these variants identified preferred sites of recombination in the parental viruses, including both short direct repeats and inverted repeats. One instance of insert deletion through recombination with an endogenous retrovirus was also observed. When specific sequences involved in these recombination events were eliminated, deletion variants still arose with the same kinetics upon virus passage and by apparently similar mechanisms, although at different locations in the vectors. Our results suggest that while lengthened, insert-containing genomes can be maintained over multiple replication cycles, preferential deletions resulting in loss of the inserted sequences confer a strong selective advantage. PMID:11435579

  11. A Modified γ-Retrovirus Vector for X-Linked Severe Combined Immunodeficiency

    PubMed Central

    Hacein-Bey-Abina, S.; Pai, S.-Y.; Gaspar, H.B.; Armant, M.; Berry, C.C.; Blanche, S.; Bleesing, J.; Blondeau, J.; de Boer, H.; Buckland, K.F.; Caccavelli, L.; Cros, G.; De Oliveira, S.; Fernández, K.S.; Guo, D.; Harris, C.E.; Hopkins, G.; Lehmann, L.E.; Lim, A.; London, W.B.; van der Loo, J.C.M.; Malani, N.; Male, F.; Malik, P.; Marinovic, M.A.; McNicol, A.-M.; Moshous, D.; Neven, B.; Oleastro, M.; Picard, C.; Ritz, J.; Rivat, C.; Schambach, A.; Shaw, K.L.; Sherman, E.A.; Silberstein, L.E.; Six, E.; Touzot, F.; Tsytsykova, A.; Xu-Bayford, J.; Baum, C.; Bushman, F.D.; Fischer, A.; Kohn, D.B.; Filipovich, A.H.; Notarangelo, L.D.; Cavazzana, M.; Williams, D.A.; Thrasher, A.J.

    2014-01-01

    BACKGROUND In previous clinical trials involving children with X-linked severe combined immunodeficiency (SCID-X1), a Moloney murine leukemia virus–based γ-retrovirus vector expressing interleukin-2 receptor γ-chain (γc) complementary DNA successfully restored immunity in most patients but resulted in vector-induced leukemia through enhancer-mediated mutagenesis in 25% of patients. We assessed the efficacy and safety of a self-inactivating retrovirus for the treatment of SCID-X1. METHODS We enrolled nine boys with SCID-X1 in parallel trials in Europe and the United States to evaluate treatment with a self-inactivating (SIN) γ-retrovirus vector containing deletions in viral enhancer sequences expressing γc (SIN-γc). RESULTS All patients received bone marrow–derived CD34+ cells transduced with the SIN-γc vector, without preparative conditioning. After 12.1 to 38.7 months of follow-up, eight of the nine children were still alive. One patient died from an overwhelming adenoviral infection before reconstitution with genetically modified T cells. Of the remaining eight patients, seven had recovery of peripheral-blood T cells that were functional and led to resolution of infections. The patients remained healthy thereafter. The kinetics of CD3+ T-cell recovery was not significantly different from that observed in previous trials. Assessment of insertion sites in peripheral blood from patients in the current trial as compared with those in previous trials revealed significantly less clustering of insertion sites within LMO2 , MECOM, and other lymphoid proto-oncogenes in our patients. CONCLUSIONS This modified γ-retrovirus vector was found to retain efficacy in the treatment of SCID-X1. The long-term effect of this therapy on leukemogenesis remains unknown. (Funded by the National Institutes of Health and others; ClinicalTrials.gov numbers, NCT01410019, NCT01175239, and NCT01129544.) PMID:25295500

  12. Murine AIDS Protects Mice Against Experimental Cerebral Malaria: Down-Regulation by Interleukin 10 a T-Helper Type 1 CD4^+ Cell-Mediated Pathology

    NASA Astrophysics Data System (ADS)

    Eckwalanga, Michel; Marussig, Myriam; Dias Tavares, Marisa; Bouanga, Jean Claude; Hulier, Elisabeth; Henriette Pavlovitch, Jana; Minoprio, Paola; Portnoi, Denis; Renia, Laurent; Mazier, Dominique

    1994-08-01

    The retrovirus LP-BM5 murine leukemia virus induces murine AIDS in C57BL/6 mice that has many similarities with human AIDS; Plasmodium berghei ANKA causes experimental cerebral malaria in the same strain of mice. The outcome of malaria infection was studied in mice concurrently infected with the two pathogens. The retrovirus significantly reduced the gravity of the neurological manifestations associated with Plasmodium berghei ANKA infection. The protection against experimental cerebral malaria induced by murine AIDS increased with duration of viral infection and, hence, with the severity of the immunodeficiency. Interleukin 10, principally from splenic T cells, was shown to play a crucial role in this protection.

  13. Different Modes of Retrovirus Restriction by Human APOBEC3A and APOBEC3G In Vivo

    PubMed Central

    Stavrou, Spyridon; Crawford, Daniel; Blouch, Kristin; Browne, Edward P.; Kohli, Rahul M.; Ross, Susan R.

    2014-01-01

    The apolipoprotein B editing complex 3 (A3) cytidine deaminases are among the most highly evolutionarily selected retroviral restriction factors, both in terms of gene copy number and sequence diversity. Primate genomes encode seven A3 genes, and while A3F and 3G are widely recognized as important in the restriction of HIV, the role of the other genes, particularly A3A, is not as clear. Indeed, since human cells can express multiple A3 genes, and because of the lack of an experimentally tractable model, it is difficult to dissect the individual contribution of each gene to virus restriction in vivo. To overcome this problem, we generated human A3A and A3G transgenic mice on a mouse A3 knockout background. Using these mice, we demonstrate that both A3A and A3G restrict infection by murine retroviruses but by different mechanisms: A3G was packaged into virions and caused extensive deamination of the retrovirus genomes while A3A was not packaged and instead restricted infection when expressed in target cells. Additionally, we show that a murine leukemia virus engineered to express HIV Vif overcame the A3G-mediated restriction, thereby creating a novel model for studying the interaction between these proteins. We have thus developed an in vivo system for understanding how human A3 proteins use different modes of restriction, as well as a means for testing therapies that disrupt HIV Vif-A3G interactions. PMID:24851906

  14. One hundred twenty years of koala retrovirus evolution determined from museum skins.

    PubMed

    Ávila-Arcos, María C; Ho, Simon Y W; Ishida, Yasuko; Nikolaidis, Nikolas; Tsangaras, Kyriakos; Hönig, Karin; Medina, Rebeca; Rasmussen, Morten; Fordyce, Sarah L; Calvignac-Spencer, Sébastien; Willerslev, Eske; Gilbert, M Thomas P; Helgen, Kristofer M; Roca, Alfred L; Greenwood, Alex D

    2013-02-01

    Although endogenous retroviruses are common across vertebrate genomes, the koala retrovirus (KoRV) is the only retrovirus known to be currently invading the germ line of its host. KoRV is believed to have first infected koalas in northern Australia less than two centuries ago. We examined KoRV in 28 koala museum skins collected in the late 19th and 20th centuries and deep sequenced the complete proviral envelope region from five northern Australian specimens. Strikingly, KoRV env sequences were conserved among koalas collected over the span of a century, and two functional motifs that affect viral infectivity were fixed across the museum koala specimens. We detected only 20 env polymorphisms among the koalas, likely representing derived mutations subject to purifying selection. Among northern Australian koalas, KoRV was already ubiquitous by the late 19th century, suggesting that KoRV evolved and spread among koala populations more slowly than previously believed. Given that museum and modern koalas share nearly identical KoRV sequences, it is likely that koala populations, for more than a century, have experienced increased susceptibility to diseases caused by viral pathogenesis. PMID:22983950

  15. One Hundred Twenty Years of Koala Retrovirus Evolution Determined from Museum Skins

    PubMed Central

    Ávila-Arcos, María C.; Ho, Simon Y.W.; Ishida, Yasuko; Nikolaidis, Nikolas; Tsangaras, Kyriakos; Hönig, Karin; Medina, Rebeca; Rasmussen, Morten; Fordyce, Sarah L.; Calvignac-Spencer, Sébastien; Willerslev, Eske; Gilbert, M. Thomas P.; Helgen, Kristofer M.; Roca, Alfred L.; Greenwood, Alex D.

    2013-01-01

    Although endogenous retroviruses are common across vertebrate genomes, the koala retrovirus (KoRV) is the only retrovirus known to be currently invading the germ line of its host. KoRV is believed to have first infected koalas in northern Australia less than two centuries ago. We examined KoRV in 28 koala museum skins collected in the late 19th and 20th centuries and deep sequenced the complete proviral envelope region from five northern Australian specimens. Strikingly, KoRV env sequences were conserved among koalas collected over the span of a century, and two functional motifs that affect viral infectivity were fixed across the museum koala specimens. We detected only 20 env polymorphisms among the koalas, likely representing derived mutations subject to purifying selection. Among northern Australian koalas, KoRV was already ubiquitous by the late 19th century, suggesting that KoRV evolved and spread among koala populations more slowly than previously believed. Given that museum and modern koalas share nearly identical KoRV sequences, it is likely that koala populations, for more than a century, have experienced increased susceptibility to diseases caused by viral pathogenesis. PMID:22983950

  16. Retrovirus-like promoters in the human genome

    SciTech Connect

    Feuchter, A.E.

    1991-01-01

    Several families of repetitive sequences related to integrated retroviruses have been identified in the human genome. The largest of these families, the RTVL-H family, has close to 1,000 members, in addition to several hundred solitary long terminal repeats (LTRs). The similarity of these LTRs in structure and organization to the LTRs of proviruses suggest that they may act as transcriptional regulators of gene expression. To test this hypothesis, the author initially examined the ability of different RTVL-H LTRs to drive expression of the reporter gene chloramphenicol acetyltransferase (CAT) in a variety of human and murine cell lines. These studies revealed that RTVL-H LTRs are heterogeneous in their ability to regulate the expression of linked genes. Although all of five LTRs tested could promote expression of the CAT gene, their relative promoter activities as well as range of activities varied widely. RTVL-H LTRs were also shown to contain sequences that could increase transcription from the human [beta]-globin promoter and be influenced by SV40 enhancer sequences. The results of additional studies suggested that RTVL-H LTRs may have the ability to influence the expression of unrelated cellular genes. Taken together, these results suggest a general evolutionary role for RTVL-H LTRs in the regulation of gene expression and raise the possibility that activation or rearrangements involving these sequences may alter the normal regulation of cellular genes and thus contribute to human disease.

  17. Conference highlights of the 16th International Conference on Human Retrovirology: HTLV and related retroviruses, 26-30 June 2013, Montreal, Canada.

    PubMed

    Barbeau, Benoit; Hiscott, John; Bazarbachi, Ali; Carvalho, Edgar; Jones, Kathryn; Martin, Fabiola; Matsuoka, Masao; Murphy, Edward L; Ratner, Lee; Switzer, William M; Watanabe, Toshiki

    2014-01-01

    The 16th International Conference on Human Retrovirology: HTLV and Related Retroviruses was held in Montreal, Québec from June 26th to June 30th, 2013 and was therefore hosted by a Canadian city for the first time. The major topic of the meeting was human T-lymphotropic viruses (HTLVs) and was covered through distinct oral and poster presentation sessions: clinical research, animal models, immunology, molecular and cellular biology, human endogenous and emerging exogenous retroviruses and virology. In this review, highlights of the meeting are provided by different experts for each of these research areas. PMID:24558960

  18. Conference Highlights of the 16th International Conference on Human Retrovirology: HTLV and Related Retroviruses, 26–30 June 2013, Montreal, Canada

    PubMed Central

    2014-01-01

    The 16th International Conference on Human Retrovirology: HTLV and Related Retroviruses was held in Montreal, Québec from June 26th to June 30th, 2013 and was therefore hosted by a Canadian city for the first time. The major topic of the meeting was human T-lymphotropic viruses (HTLVs) and was covered through distinct oral and poster presentation sessions: clinical research, animal models, immunology, molecular and cellular biology, human endogenous and emerging exogenous retroviruses and virology. In this review, highlights of the meeting are provided by different experts for each of these research areas. PMID:24558960

  19. Defective herpes simplex virus type 1 vectors harboring gag, pol, and env genes can be used to rescue defective retrovirus vectors.

    PubMed Central

    Savard, N; Cosset, F L; Epstein, A L

    1997-01-01

    A retroviral packaging transcription unit was constructed in which the Moloney murine leukemia virus (MoMLV) gag-pol and env genes are expressed under the control of herpesvirus regulatory sequences. This transcription unit, lacking long terminal repeats, primer binding sites, and most of the retrovirus packaging signal but retaining both retroviral donor and acceptor splice sites, was cloned into a herpes simplex virus type 1 (HSV-1) amplicon plasmid, and amplicon vectors (the gag-pol-env [GPE] vectors) were generated by using a defective HSV-1 vector as helper virus. The GPE vector population was used to infect human TE671 cells (ATCC CRL 8805), harboring a lacZ provirus (TE-lac2 cells), and supernatants of infected cells were collected and filtered at different times after infection. These supernatants were found to contain infectious ecotropic lacZ retroviral particles, as shown both by reverse transcription-PCR and by their ability to transduce a beta-galactosidase activity to murine NIH 3T3 cells but not to human TE671 cells. The titer of retroviral vectors released by GPE vector-infected TE-lac2 cells increased with the dose of infectious amplicon particles. Retrovirus vector production was inhibited by superinfection with helper virus, indicating that helper virus coinfection negatively interfered with retrovirus production. Induction of retrovirus vectors by GPE vectors was neutralized by anti-HSV-1 but not by anti-MoMLV antiserum, while transduction of beta-galactosidase activity to NIH 3T3 cells by supernatants of GPE vector-infected TE-lac2 cells was neutralized by anti-MoMLV antiserum. These results demonstrate that HSV-1 GPE amplicon vectors can rescue defective lacZ retrovirus vectors and suggest that they could be used as a sort of launching ramp to fire defective retrovirus vectors from within virtually any in vitro or in vivo cell type containing defective retroviral vectors. PMID:9094692

  20. Human Immunodeficiency Virus and Related Retroviruses

    PubMed Central

    Nájera, Rafael; Herrera, M. I.; Andrés, R. de

    1987-01-01

    This paper summarizes the current knowledge on the human immunodeficiency virus (HIV) and related retroviruses, describing basic characteristics of this new group of viruses such as morphologic and genetic structure, biological and cultural properties, virus growth characteristics, genetic variability and virus replication. The discovery of new human and simian retroviruses has prompted the World Health Organization (WHO) to convene a group of experts to establish criteria for their characterization. This will allow rapid identification of new variants that may arise and allow public health measures to be implemented accordingly. Different approaches are made to nomenclature in view of the evolution of knowledge about these viruses, and a system of nomenclature has been proposed by the WHO working group. This system, inspired by the one developed for the influenza viruses, is practical and descriptive, providing information on the origins of the organism and its type. Images PMID:2829446

  1. Viral Engineering of Chimeric Antigen Receptor Expression on Murine and Human T Lymphocytes.

    PubMed

    Hammill, Joanne A; Afsahi, Arya; Bramson, Jonathan L; Helsen, Christopher W

    2016-01-01

    The adoptive transfer of a bolus of tumor-specific T lymphocytes into cancer patients is a promising therapeutic strategy. In one approach, tumor specificity is conferred upon T cells via engineering expression of exogenous receptors, such as chimeric antigen receptors (CARs). Here, we describe the generation and production of both murine and human CAR-engineered T lymphocytes using retroviruses. PMID:27581020

  2. Amino-terminal amino acid sequence of the major structural polypeptides of avian retroviruses: sequence homology between reticuloendotheliosis virus p30 and p30s of mammalian retroviruses.

    PubMed Central

    Hunter, E; Bhown, A S; Bennett, J C

    1978-01-01

    The major structural polypeptides, p30 of reticuloendotheliosis virus (REV) (strain T) and p27 of avian sarcoma virus B77, have been compared with regard to amino acid composition. NH2-terminal amino acid sequence, and immunological crossreactions. The amino acid composition of the two polypeptides is distinct, and a comparison of the first 30 NH2-terminal amino acids of REV p30 with that for the first 25 of B77 p27 yields only three homologous residues. In competition radioimmunoassays the polypeptides show no crossreactivity. A comparison of the amino acid composition and NH2-terminal amino acid sequence of REV p30 with those reported for several mammalian retrovirus p30s shows remarkable similarities. Both REV and mammalian p30s contain a large number of polar residues in their amino acid composition and show approximately 40% homology in the first 30 NH2-terminal amino acids. No crossreactivity could be observed, however, in competition radioimmunoassays between Rauscher murine leukemia virus p30 and that of REV. The observations reported here suggest a close evolutionary relationship between REV and the mammalian retroviruses. Images PMID:208072

  3. Multiple invasions of an infectious retrovirus in cat genomes

    PubMed Central

    Shimode, Sayumi; Nakagawa, So; Miyazawa, Takayuki

    2015-01-01

    Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of host germ-line cells. While most ERVs are defective, some are active and express viral proteins. The RD-114 virus is a replication-competent feline ERV, and several feline cell lines produce infectious RD-114 viral particles. All domestic cats are considered to have an ERV locus encoding a replication-competent RD-114 virus in their genomes; however, the locus has not been identified. In this study, we investigated RD-114 virus-related proviral loci in genomes of domestic cats, and found that none were capable of producing infectious viruses. We also found that all domestic cats have an RD-114 virus-related sequence on chromosome C2, termed RDRS C2a, but populations of the other RDRSs are different depending on the regions where cats live or breed. Our results indicate that RDRS C2a, the oldest RD-114-related provirus, entered the host genome before an ancestor of domestic cats started diverging and the other new RDRSs might have integrated into migrating cats in Europe. We also show that infectious RD-114 virus can be resurrected by the recombination between two non-infectious RDRSs. From these data, we conclude that cats do not harbor infectious RD-114 viral loci in their genomes and RD-114-related viruses invaded cat genomes multiple times. PMID:25641657

  4. Flamenco, a gene controlling the gypsy retrovirus of Drosophila melanogaster.

    PubMed

    Prud'homme, N; Gans, M; Masson, M; Terzian, C; Bucheton, A

    1995-02-01

    Gypsy is an endogenous retrovirus of Drosophila melanogaster. It is stable and does not transpose with detectable frequencies in most Drosophila strains. However, we have characterized unstable strains, known as MG, in which it transposes at high frequency. These stocks contain more copies of gypsy than usual stocks. Transposition results in mutations in several genes such as ovo and cut. They are stable and are due to gypsy insertions. Integrations into the ovoD1 female sterile-dominant mutation result in a null allele of the gene and occurrence of fertile females. This phenomenon, known as the ovoD1 reversion assay, can be used to quantitate gypsy activity. We have shown that the properties of MG strains result from mutation of a host gene that we called flamenco (flam). It has a strict maternal effect on gypsy mobilization: transposition occurs at high frequency only in the germ line of the progeny of females homozygous for mutations of the gene. It is located at position 65.9 (20A1-3) on the X chromosome. The mutant allele present in MG strains is essentially recessive. Flamenco seems to control the infective properties of gypsy. PMID:7713426

  5. The retrovirus/superantigen hypothesis of multiple sclerosis.

    PubMed

    Emmer, Alexander; Staege, Martin S; Kornhuber, Malte E

    2014-11-01

    The pathogenesis of multiple sclerosis (MS) is as yet unknown. Commonly, MS is assumed to be due to an autoimmune inflammation of the central nervous system (CNS). Neurodegeneration is regarded to be a secondary reaction. This concept is increasingly being challenged. Human endogenous retroviruses (HERV) that could be locally activated in the CNS have been proposed as an alternative concept. HERV-encoded envelope proteins (env) can act as strong immune stimulators (superantigens). Thus, slow disease progression following neurodegeneration might be induced by re-activation of HERV expression directly, while relapses in parallel to inflammation might be secondary to the expression of HERV-encoded superantigens. It has been shown previously that T-cell superantigens are capable to induce a cellular inflammatory reaction in the CNS of experimental animals similar to that in MS. Furthermore, B-cell superantigens have been shown to activate blood leucocytes in vitro to produce immunoglobulin in an oligoclonal manner. It remains to be established, whether the outlined hypothesis accords with all known features of MS. Furthermore, anti-HERV agents may be taken into consideration to enrich and improve MS therapy. PMID:25138639

  6. Multiple invasions of an infectious retrovirus in cat genomes.

    PubMed

    Shimode, Sayumi; Nakagawa, So; Miyazawa, Takayuki

    2015-01-01

    Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of host germ-line cells. While most ERVs are defective, some are active and express viral proteins. The RD-114 virus is a replication-competent feline ERV, and several feline cell lines produce infectious RD-114 viral particles. All domestic cats are considered to have an ERV locus encoding a replication-competent RD-114 virus in their genomes; however, the locus has not been identified. In this study, we investigated RD-114 virus-related proviral loci in genomes of domestic cats, and found that none were capable of producing infectious viruses. We also found that all domestic cats have an RD-114 virus-related sequence on chromosome C2, termed RDRS C2a, but populations of the other RDRSs are different depending on the regions where cats live or breed. Our results indicate that RDRS C2a, the oldest RD-114-related provirus, entered the host genome before an ancestor of domestic cats started diverging and the other new RDRSs might have integrated into migrating cats in Europe. We also show that infectious RD-114 virus can be resurrected by the recombination between two non-infectious RDRSs. From these data, we conclude that cats do not harbor infectious RD-114 viral loci in their genomes and RD-114-related viruses invaded cat genomes multiple times. PMID:25641657

  7. Retroviruses facilitate the rapid evolution of the mammalian placenta

    PubMed Central

    Chuong, Edward B.

    2015-01-01

    The mammalian placenta exhibits elevated expression of endogenous retroviruses (ERVs), but the evolutionary significance of this feature remains unclear. I propose that ERV-mediated regulatory evolution was, and continues to be, an important mechanism underlying the evolution of placenta development. Many recent studies have focused on the co-option of ERV-derived genes for specific functional adaptations in the placenta. However, the co-option of ERV-derived regulatory elements has the potential to co-opt entire gene regulatory networks, which, I argue, would facilitate relatively rapid developmental evolution of the placenta. I suggest a model in which an ancient retroviral infection led to the establishment of the ancestral placental developmental gene network through the co-option of ERV-derived regulatory elements. Consequently, placenta development would require elevated tolerance to ERV activity, which in turn would expose a continuous stream of novel ERV mutations that may have catalyzed the developmental diversification of the mammalian placenta. PMID:23873343

  8. Flamenco, a gene controlling the gypsy retrovirus of drosophila melanogaster

    SciTech Connect

    Prud`homme, N.; Gans, M.; Masson, M.; Terzian, C.; Bucheton, A.

    1995-02-01

    Gypsy is an endogenous retrovirus of Drosophila melanogaster. It is table and does not transpose with detectable frequencies in most Drosophila strains. However, we have characterized unstable strains, known as MG, in which it transposes at high frequency. These stocks contain more copies of gypsy than usual stocks. Transposition results in mutations in several genes such as ovo and cut. They are stable and are due to gypsy insertions. Integrations into the ovo{sup D1} female sterile-dominant mutation result in a null allele of the gene and occurrence of fertile females. This phenomenon, known as the ovo{sup D1} reversion assay, can be used to quantitate gypsy activity. We have shown that the properties of MG strains result from mutation of a host gene that we called flamenco (flam). It has a strict maternal effect on gypsy mobilization: transposition occurs at high frequency only in the germ line of the progeny of females homozygous for mutations of the gene. It is located at position 65.9 (20A1-3) on the X chromosome. The mutant allele present in MG strains is essentially recessive. Flamenco seems to control the infective properties of gypsy. 40 refs., 10 figs., 6 tabs.

  9. Sox4 cooperates with PU.1 haploinsufficiency in murine myeloid leukemia

    PubMed Central

    Aue, Georg; Du, Yang; Cleveland, Susan M.; Smith, Stephen B.; Davé, Utpal P.; Liu, Delong; Weniger, Marc A.; Metais, Jean Yves; Jenkins, Nancy A.; Copeland, Neal G.

    2011-01-01

    Cooperation of multiple mutations is thought to be required for cancer development. In previous studies, murine myeloid leukemias induced by transducing wild-type bone marrow progenitors with a SRY sex determining region Y-box 4 (Sox4)–expressing retrovirus frequently carried proviral insertions at Sfpi1, decreasing its mRNA levels, suggesting that reduced Sfpi1 expression cooperates with Sox4 in myeloid leukemia induction. In support of this hypothesis, we show here that mice receiving Sox4 virus-infected Sfpi1ko/+ bone marrow progenitors developed myeloid leukemia with increased penetrance and shortened latency. Interestingly, Sox4 expression further decreased Sfpi1 transcription. Ectopic SOX4 expression reduced endogenous PU.1 mRNA levels in HL60 promyelocytes, and decreased Sfpi1 mRNA levels were also observed in the spleens of leukemic and preleukemic mice receiving Sox4 virus-infected wild-type bone marrow cells. In addition, Sox4 protein bound to a critical upstream regulatory element of Sfpi1 in ChIP assays. Such cooperation probably occurs in de novo human acute myeloid leukemias, as an analysis of 285 acute myeloid leukemia patient samples found a significant negative correlation between SOX4 and PU.1 expression. Our results establish a novel cooperation between Sox4 and reduced Sfpi1 expression in myeloid leukemia development and suggest that SOX4 could be an important new therapeutic target in human acute myeloid leukemia. PMID:21878674

  10. Lack of antiviral antibody response in koalas infected with koala retroviruses (KoRV).

    PubMed

    Fiebig, Uwe; Keller, Martina; Möller, Annekatrin; Timms, Peter; Denner, Joachim

    2015-02-16

    Many wild koalas are infected with the koala retrovirus, KoRV, some of which suffer from lymphoma and chlamydial disease. Three subgroups, KoRV-A, KoRV-B and KoRV-J, have so far been described. It is well known that other closely related gammaretroviruses can induce tumours and severe immunodeficiencies in their respective hosts and a possible role for KoRV infection in lymphoma and chlamydial disease in koalas has been suggested. In many wild koalas, KoRV-A has become endogenised, i.e., it is integrated in the germ-line and is passed on with normal cellular genes. In this study, sera from koalas in European zoos and from wild animals in Australia were screened for antibodies against KoRV-A. These naturally infected animals all carry endogenous KoRV-A and two zoo animals are also infected with KoRV-B. The antibody response is generally an important diagnostic tool for detecting retrovirus infections. However, when Western blot analyses were performed using purified virus or recombinant proteins corresponding to KoRV-A, none of the koalas tested positive for specific antibodies, suggesting a state of tolerance. These results have implications for koala vaccination, as they suggest that therapeutic immunisation of animals carrying and expressing endogenous KoRV-A will not be successful. However, it remains unclear whether these animals can be immunised against KoRV-B and immunisation of uninfected koalas could still be worthwhile. PMID:25596496

  11. Endogenous ochronosis.

    PubMed

    Turgay, E; Canat, D; Gurel, M S; Yuksel, T; Baran, M F; Demirkesen, C

    2009-12-01

    Endogenous ochronosis or alkaptonuria is a rare, autosomal recessive disease of tyrosine metabolism that is caused by a deficiency of the enzyme homogentisic acid oxidase. The disease results in the accumulation and deposition of homogentisic acid in the cartilage, eyelids, forehead, cheeks, axillae, genital region, buccal mucosa, larynx, tympanic membranes, and tendons. The disease generally presents in adults with arthritis and skin abnormalities; occasionally, involvement of other organs may be seen. A 49-year-old man was referred to our clinic with verrucous lesions on his hands. On physical examination, caviar-like ochronotic papules were found around his eyes and the helix cartilage of his ears, and on the dorsa of both hands. There were brown macules on the sclera (Osler's sign). The patient had arthritis and nephrolithiasis, and a sample of his urine darkened upon standing. Histopathological examination showed deposition of ochronotic pigment. High-dose ascorbic acid was given, and the patient showed improvement on follow-up examination 6 months later. PMID:20055850

  12. Tracking interspecies transmission and long-term evolution of an ancient retrovirus using the genomes of modern mammals.

    PubMed

    Diehl, William E; Patel, Nirali; Halm, Kate; Johnson, Welkin E

    2016-01-01

    Mammalian genomes typically contain hundreds of thousands of endogenous retroviruses (ERVs), derived from ancient retroviral infections. Using this molecular 'fossil' record, we reconstructed the natural history of a specific retrovirus lineage (ERV-Fc) that disseminated widely between ~33 and ~15 million years ago, corresponding to the Oligocene and early Miocene epochs. Intercontinental viral spread, numerous instances of interspecies transmission and emergence in hosts representing at least 11 mammalian orders, and a significant role for recombination in diversification of this viral lineage were also revealed. By reconstructing the canonical retroviral genes, we identified patterns of adaptation consistent with selection to maintain essential viral protein functions. Our results demonstrate the unique potential of the ERV fossil record for studying the processes of viral spread and emergence as they play out across macro-evolutionary timescales, such that looking back in time may prove insightful for predicting the long-term consequences of newly emerging viral infections. PMID:26952212

  13. Human retroviruses and AIDS, 1991. [CONTAINS GLOSSARY

    SciTech Connect

    Myers, G.; Korber, B. ); Berzofsky, J.A.; Pavlakis, G.N. ); Smith, R.F. )

    1991-05-01

    This compendium and the accompanying floppy diskettes are the result of an effort to compile and rapidly publish all relevant molecular data concerning the human immunodeficiency viruses (HIV) and related retroviruses.The scope of the compendium and database is best summarized by the five parts that it comprises: (1) HIV and SIV Nucleotide Sequences; (2) Amino Acid Sequences; (3) Analyses; (4) Related Sequences; and (5) Database Communications. Information within all the parts is updated at least twice in each year, which accounts for the modes of binding and pagination in the compendium.

  14. Retrovirus Restriction by TRIM5 Proteins Requires Recognition of Only a Small Fraction of Viral Capsid Subunits

    PubMed Central

    Shi, Jiong; Friedman, David B.

    2013-01-01

    The host restriction factors TRIM5α and TRIMCyp potently inhibit retrovirus infection by binding to the incoming retrovirus capsid. TRIM5 proteins are dimeric, and their association with the viral capsid appears to be enhanced by avidity effects owing to formation of higher-order oligomeric complexes. We examined the stoichiometric requirement for TRIM5 functional recognition by quantifying the efficiencies of restriction of HIV-1 and murine leukemia virus (MLV) particles containing various proportions of restriction-sensitive and -insensitive CA subunits. Both TRIMCyp and TRIM5α inhibited infection of retrovirus particles containing as little as 25% of the restriction-sensitive CA protein. Accordingly, we also observed efficient binding of TRIMCyp in vitro to capsid assemblies containing as little as one-fourth wild-type CA protein. Paradoxically, the ability of HIV-1 particles to abrogate TRIMCyp restriction in trans was more strongly dependent on the fraction of wild-type CA than was restriction of infection. Collectively, our results indicate that TRIM5 restriction factors bind to retroviral capsids in a highly cooperative manner and suggest that TRIM5 can engage a capsid lattice containing a minimum of three or fewer recognizable subunits per hexamer. Our study supports a model in which localized binding of TRIM5 to the viral capsid nucleates rapid polymerization of a TRIM5 lattice on the capsid surface. PMID:23785198

  15. Inorganic phosphate export by the retrovirus receptor XPR1 in metazoans.

    PubMed

    Giovannini, Donatella; Touhami, Jawida; Charnet, Pierre; Sitbon, Marc; Battini, Jean-Luc

    2013-06-27

    Inorganic phosphate uptake is a universal function accomplished by transporters that are present across the living world. In contrast, no phosphate exporter has ever been identified in metazoans. Here, we show that depletion of XPR1, a multipass membrane molecule initially identified as the cell-surface receptor for xenotropic and polytropic murine leukemia retroviruses (X- and P-MLV), induced a decrease in phosphate export and that reintroduction of various XPR1 proteins, from fruit fly to human, rescued this defect. Inhibition of phosphate export was also obtained with a soluble ligand generated from the envelope-receptor-binding domain of X-MLV in all human cell lines tested, as well as in diverse stem cells and epithelial cells derived from renal proximal tubules, the main site of phosphate homeostasis regulation. These results provide new insights on phosphate export in metazoans and the role of Xpr1 in this function. PMID:23791524

  16. Convergent Evolution of Ribonuclease H in LTR Retrotransposons and Retroviruses

    PubMed Central

    Ustyantsev, Kirill; Novikova, Olga; Blinov, Alexander; Smyshlyaev, Georgy

    2015-01-01

    Ty3/Gypsy long terminals repeat (LTR) retrotransposons are structurally and phylogenetically close to retroviruses. Two notable structural differences between these groups of genetic elements are 1) the presence in retroviruses of an additional envelope gene, env, which mediates infection, and 2) a specific dual ribonuclease H (RNH) domain encoded by the retroviral pol gene. However, similar to retroviruses, many Ty3/Gypsy LTR retrotransposons harbor additional env-like genes, promoting concepts of the infective mode of these retrotransposons. Here, we provide a further line of evidence of similarity between retroviruses and some Ty3/Gypsy LTR retrotransposons. We identify that, together with their additional genes, plant Ty3/Gypsy LTR retrotransposons of the Tat group have a second RNH, as do retroviruses. Most importantly, we show that the resulting dual RNHs of Tat LTR retrotransposons and retroviruses emerged independently, providing strong evidence for their convergent evolution. The convergent resemblance of Tat LTR retrotransposons and retroviruses may indicate similar selection pressures acting on these diverse groups of elements and reveal potential evolutionary constraints on their structure. We speculate that dual RNH is required to accelerate retrotransposon evolution through increased rates of strand transfer events and subsequent recombination events. PMID:25605791

  17. Multiple sclerosis retrovirus-like envelope gene: Role of the chromosome 20 insertion

    PubMed Central

    Varadé, Jezabel; García-Montojo, Marta; de la Hera, Belén; Camacho, Iris; García-Martínez, Mª. Ángel; Arroyo, Rafael; Álvarez-Lafuente, Roberto; Urcelay, Elena

    2015-01-01

    Background The genetic basis involved in multiple sclerosis (MS) susceptibility was not completely revealed by genome-wide association studies. Part of it could lie in repetitive sequences, as those corresponding to human Endogenous Retroviruses (HERVs). Retrovirus-like particles were isolated from MS patients and the genome of the MS-associated retrovirus (MSRV) was the founder of the HERV-W family. We aimed to ascertain which chromosomal origin encodes the pathogenic ENV protein by genomic analysis of the HERV-W insertions. Methods/results In silico analyses allowed to uncover putative open reading frames containing the specific sequence previously reported for MSRV-like envelope (env) detection. Out of the 261 genomic insertions of HERV-W env, only 9 copies harbor the specific primers and probe featuring MSRV-like env. The copy from chromosome 20 was further studied considering its size, a truncated homologue of the functional HERV-W env sequence encoding syncytin. High Resolution Melting analysis of this sequence identified two single nucleotide polymorphisms, subsequently genotyped by Taqman chemistry in 668 MS patients and 678 healthy controls. No significant association of these polymorphisms with MS risk was evidenced. Transcriptional activity of this MSRV-like env copy was detected in peripheral blood mononuclear cells from patients and controls. RNA expression levels of chromosome 20-specific MSRV-like env did not show significant differences between MS patients and controls, neither were related to genotypes of the two mentioned polymorphisms. Conclusions The lack of association with MS risk of the identified polymorphisms together with the transcription results discard chromosome 20 as genomic origin of MSRV-like env. PMID:26675450

  18. A revised nomenclature for transcribed human endogenous retroviral loci

    PubMed Central

    2011-01-01

    Background Endogenous retroviruses (ERVs) and ERV-like sequences comprise 8% of the human genome. A hitherto unknown proportion of ERV loci are transcribed and thus contribute to the human transcriptome. A small proportion of these loci encode functional proteins. As the role of ERVs in normal and diseased biological processes is not yet established, transcribed ERV loci are of particular interest. As more transcribed ERV loci are likely to be identified in the near future, the development of a systematic nomenclature is important to ensure that all information on each locus can be easily retrieved. Results Here we present a revised nomenclature of transcribed human endogenous retroviral loci that sorts loci into groups based on Repbase classifications. Each symbol is of the format ERV + group symbol + unique number. Group symbols are based on a mixture of Repbase designations and well-supported symbols used in the literature. The presented guidelines will allow newly identified loci to be easily incorporated into the scheme. Conclusions The naming system will be employed by the HUGO Gene Nomenclature Committee for naming transcribed human ERV loci. We hope that the system will contribute to clarifying a certain aspect of a sometimes confusing nomenclature for human endogenous retroviruses. The presented system may also be employed for naming transcribed loci of human non-ERV repeat loci. PMID:21542922

  19. Towards liver-directed gene therapy: retrovirus-mediated gene transfer into human hepatocytes.

    PubMed

    Grossman, M; Raper, S E; Wilson, J M

    1991-11-01

    Liver-directed gene therapy is being considered in the treatment of inherited metabolic diseases. One approach we are considering is the transplantation of autologous hepatocytes that have been genetically modified with recombinant retroviruses ex vivo. We describe, in this report, techniques for isolating human hepatocytes and efficiently transducing recombinant genes into primary cultures. Hepatocytes were isolated from tissue of four different donors, plated in primary culture, and exposed to recombinant retroviruses expressing either the LacZ reporter gene or the cDNA for rabbit LDL receptor. The efficiency of gene transfer under optimal conditions, as determined by Southern blot analysis, varied from a maximum of one proviral copy per cell to a minimum of 0.1 proviral copy per cell. Cytochemical assays were used to detect expression of the recombinant derived proteins, E. coli beta-galactosidase and rabbit LDL receptor. Hepatocytes transduced with the LDL receptor gene expressed levels of receptor protein that exceeded the normal endogenous levels. The ability to isolate and genetically modify human hepatocytes, as described in this report, is an important step towards the development of liver-directed gene therapies in humans. PMID:1767337

  20. Sequence variation of koala retrovirus transmembrane protein p15E among koalas from different geographic regions.

    PubMed

    Ishida, Yasuko; McCallister, Chelsea; Nikolaidis, Nikolas; Tsangaras, Kyriakos; Helgen, Kristofer M; Greenwood, Alex D; Roca, Alfred L

    2015-01-15

    The koala retrovirus (KoRV), which is transitioning from an exogenous to an endogenous form, has been associated with high mortality in koalas. For other retroviruses, the envelope protein p15E has been considered a candidate for vaccine development. We therefore examined proviral sequence variation of KoRV p15E in a captive Queensland and three wild southern Australian koalas. We generated 163 sequences with intact open reading frames, which grouped into 39 distinct haplotypes. Sixteen distinct haplotypes comprising 139 of the sequences (85%) coded for the same polypeptide. Among the remaining 23 haplotypes, 22 were detected only once among the sequences, and each had 1 or 2 non-synonymous differences from the majority sequence. Several analyses suggested that p15E was under purifying selection. Important epitopes and domains were highly conserved across the p15E sequences and in previously reported exogenous KoRVs. Overall, these results support the potential use of p15E for KoRV vaccine development. PMID:25462343

  1. Sequence variation of koala retrovirus transmembrane protein p15E among koalas from different geographic regions

    PubMed Central

    Ishida, Yasuko; McCallister, Chelsea; Nikolaidis, Nikolas; Tsangaras, Kyriakos; Helgen, Kristofer M.; Greenwood, Alex D.; Roca, Alfred L.

    2014-01-01

    The koala retrovirus (KoRV), which is transitioning from an exogenous to an endogenous form, has been associated with high mortality in koalas. For other retroviruses, the envelope protein p15E has been considered a candidate for vaccine development. We therefore examined proviral sequence variation of KoRV p15E in a captive Queensland and three wild southern Australian koalas. We generated 163 sequences with intact open reading frames, which grouped into 39 distinct haplotypes. Sixteen distinct haplotypes comprising 139 of the sequences (85%) coded for the same polypeptide. Among the remaining 23 haplotypes, 22 were detected only once among the sequences, and each had 1 or 2 non-synonymous differences from the majority sequence. Several analyses suggested that p15E was under purifying selection. Important epitopes and domains were highly conserved across the p15E sequences and in previously reported exogenous KoRVs. Overall, these results support the potential use of p15E for KoRV vaccine development. PMID:25462343

  2. A novel exogenous retrovirus sequence identified in humans.

    PubMed Central

    Griffiths, D J; Venables, P J; Weiss, R A; Boyd, M T

    1997-01-01

    A 932-bp retrovirus sequence was cloned by reverse transcriptase PCR from salivary gland tissue of a patient with Sjögren's syndrome. The sequence is related to that of type B and type D retroviruses and was present in a sucrose density gradient fraction corresponding to that of an enveloped retrovirus particle. Sequences amplified from tissues of eight individuals with or without Sjögren's syndrome had over 90% similarity and were present at a level of less than one copy per 10(3) cells. The sequence was not detectable in human genomic DNA by PCR or by Southern hybridization. These data indicate that the sequence represents an infectiously acquired genome, provisionally called human retrovirus 5. PMID:9060643

  3. Searching for Common Mammalian Retroviruses in Pediatric Idiopathic Diseases

    PubMed Central

    Jeziorski, Eric; Foulongne, Vincent; Ludwig, Catherine; Louhaem, Djamel; Rodiere, Michel; Sitbon, Marc; Courgnaud, Valérie

    2016-01-01

    Mammalian retroviruses cause a variety of diseases in their hosts, including hematological and immunodeficiency disorders. Both human T-cell leukemia (HTLV) and human immunodeficiency (HIV) viruses originated from several independent zoonotic transmissions, indicating that cross-species transmissions from animal to humans may still occur. Thus, as the risk for retroviral transmissions from animals to humans increase, we investigated whether mammalian retroviruses are involved in selected pediatric idiopathic diseases whose symptoms evoke retroviral infections. Blood samples, sera, and synovial fluids, or bone marrow cells were collected from pediatric patients under 18 years of age with different autoimmune idiopathic diseases. Overall, we screened clinical samples from 110 children using sensitive nested and semi-nested PCR strategies targeting env genes, and a C-type retrovirus reverse transcriptase (RT) activity kit. All clinical samples were free of retroviral signatures, indicating the unlikelihood of an etiological role of the retroviruses we assessed in the pediatric diseases we tested. PMID:27102168

  4. Searching for Common Mammalian Retroviruses in Pediatric Idiopathic Diseases.

    PubMed

    Jeziorski, Eric; Foulongne, Vincent; Ludwig, Catherine; Louhaem, Djamel; Rodiere, Michel; Sitbon, Marc; Courgnaud, Valérie

    2016-03-01

    Mammalian retroviruses cause a variety of diseases in their hosts, including hematological and immunodeficiency disorders. Both human T-cell leukemia (HTLV) and human immunodeficiency (HIV) viruses originated from several independent zoonotic transmissions, indicating that cross-species transmissions from animal to humans may still occur. Thus, as the risk for retroviral transmissions from animals to humans increase, we investigated whether mammalian retroviruses are involved in selected pediatric idiopathic diseases whose symptoms evoke retroviral infections. Blood samples, sera, and synovial fluids, or bone marrow cells were collected from pediatric patients under 18 years of age with different autoimmune idiopathic diseases. Overall, we screened clinical samples from 110 children using sensitive nested and semi-nested PCR strategies targeting env genes, and a C-type retrovirus reverse transcriptase (RT) activity kit. All clinical samples were free of retroviral signatures, indicating the unlikelihood of an etiological role of the retroviruses we assessed in the pediatric diseases we tested. PMID:27102168

  5. Evolution of Foamy Viruses: The Most Ancient of All Retroviruses

    PubMed Central

    Rethwilm, Axel; Bodem, Jochen

    2013-01-01

    Recent evidence indicates that foamy viruses (FVs) are the oldest retroviruses (RVs) that we know and coevolved with their hosts for several hundred million years. This coevolution may have contributed to the non-pathogenicity of FVs, an important factor in development of foamy viral vectors in gene therapy. However, various questions on the molecular evolution of FVs remain still unanswered. The analysis of the spectrum of animal species infected by exogenous FVs or harboring endogenous FV elements in their genome is pivotal. Furthermore, animal studies might reveal important issues, such as the identification of the FV in vivo target cells, which than require a detailed characterization, to resolve the molecular basis of the accuracy with which FVs copy their genome. The issues of the extent of FV viremia and of the nature of the virion genome (RNA vs. DNA) also need to be experimentally addressed. PMID:24072062

  6. Murine Typhus

    PubMed Central

    Dzul-Rosado, Karla R; Zavala Velázquez, Jorge Ernesto; Zavala-Castro, Jorge

    2012-01-01

    Rickettsia typhi: is an intracellular bacteria who causes murine typhus. His importance is reflected in the high frequency founding specific antibodies against Rickettsia typhi in several worldwide seroepidemiological studies, the seroprevalence ranging between 3-36%. Natural reservoirs of R. typhi are rats (some species belonging the Rattus Genus) and fleas (Xenopsylla cheopis) are his vector. This infection is associated with overcrowding, pollution and poor hygiene. Typically presents fever, headache, rash on trunk and extremities, in some cases may occur organ-specific complications, affecting liver, kidney, lung or brain. Initially the disease is very similar to other diseases, is very common to confuse the murine typhus with Dengue fever, therefore, ignorance of the disease is a factor related to complications or non-specific treatments for the resolution of this infection. This paper presents the most relevant information to consider about the rickettsiosis caused by Rickettsia typhi. PMID:24893060

  7. HERV-K(HML-2), the Best Preserved Family of HERVs: Endogenization, Expression, and Implications in Health and Disease

    PubMed Central

    Hohn, Oliver; Hanke, Kirsten; Bannert, Norbert

    2013-01-01

    Retroviruses that have the ability to infect germ line cells can become an integral and inherited part of the host genome. About 8% of the human chromosomal DNA consists of sequences derived from infections by retroviruses that presumably circulated 2–40 millions of years ago, and some elements are actually much older. Post-insertional recombinations, deletions, and mutations have rendered all known human endogenous retroviruses (HERVs) non-infectious. However some, particularly the most recently acquired proviruses of the HERV-K(HML-2) family, can expresses viral proteins and produce viral particles. In this review we will first discuss the major aspects of the endogenization process and peculiarities of the different HERV-K families. We will then focus on the genes and proteins encoded by HERV-K(HML-2) as well as inactivation of these proviruses by postinsertional mutations and their inhibition by antiretroviral factors. After describing the evolutionary interplay between host and endogenous retrovirus we will delve deeper into the currently limited understanding of HERV-K and its possible association with disease, particularly tumorigenesis. PMID:24066280

  8. Endogenization of mouse mammary tumor virus (MMTV)-like elements in genomes of pikas (Ochotona sp.).

    PubMed

    Lemos de Matos, Ana; de Sousa-Pereira, Patrícia; Lissovsky, Andrey A; van der Loo, Wessel; Melo-Ferreira, José; Cui, Jie; Esteves, Pedro J

    2015-12-01

    Despite the finding in European rabbit and other leporid genomes of the first ever described endogenous lentivirus and of a European rabbit exclusive endogenous gammaretrovirus, until now no exogenous retroviruses have been isolated in Lagomorpha species. Nevertheless, looking for the presence of endogenous retroviruses (ERVs) in the species genomes could lead to the discovery of retroviral lineages yet to be found in Lagomorpha. Different mammalian genomes harbor endogenous viral sequences phylogenetically close to the betaretrovirus mouse mammary tumor virus (MMTV), propelling us to look for such retroviral "fossil" in American pika (Ochotona princeps) and European rabbit (Oryctolagus cuniculus) genomes. By performing genomic mining using MMTV gag and LTR as query sequences, we found that such viral elements were absent from the European rabbit genome. Oppositely, significant matches were found in American pika, and more importantly, a nearly complete MMTV-like virus (Pika-BERV) was identified. Using Pika-BERV gag and LTR as templates, we found similar sequences endogenized in different pika (Ochotona sp.) species. The orthology of the LTR flanking region between some pika species supported shared ancestry of specific endogenous betaretroviruses, while in other pika species similar sequences, but not orthologous, should have resulted from independent insertions. Our study supports the possible existence of infecting exogenous betaretroviruses for a long term, after the divergence of Ochotonidae from Leporidae, but yet to be identified. PMID:26151606

  9. Follicular dendritic cell function and murine AIDS.

    PubMed Central

    Masuda, A; Burton, G F; Fuchs, B A; Bhogal, B S; Rupper, R; Szakal, A K; Tew, J G

    1994-01-01

    Infection of mice with LP-BM5 elicits an immunodeficiency state referred to as murine acquired immune deficiency syndrome (MAIDS). Shortly after infection, retrovirus particles become associated with follicular dendritic cells (FDC) and this study was undertaken to determine whether retroviruses alter FDC functions. The FDC functions examined included the ability to: (1) retain antigen (Ag) trapped prior to infection; (2) trap new Ag after infection; (3) maintain specific IgG responses; and (4) provide co-stimulatory signals to B cells. Mice were infected with LP-BM5 and the ability of their FDC to trap and retain 125I-Ag (HSA) was assessed. Serum anti-HSA levels were monitored and FDC co-stimulatory activity was indicated by increased B-cell proliferation. HSA trapped on FDC prior to infection began to disappear by 3 weeks and was practically gone by 6 weeks. Serum anti-HSA titres were maintained normally for about 3 weeks after infection and then declined precipitously. The ability of FDC to trap new Ag began to disappear around the second and third week of infection and was markedly depressed by the fourth week. However, FDC recovered from infected mice retained their ability to co-stimulate anti-mu- and interleukin-4 (IL-4)-activated B cells throughout a 5-week period. In short, the ability of FDC to trap and retain specific Ag and maintain specific antibody levels was markedly depressed after retrovirus infection. However, FDC from infected mice continued to provide co-stimulatory signals and these signals may contribute to the lymphadenopathy and splenomegaly characteristic of MAIDS. Images Figure 4 PMID:8132218

  10. Retrovirus transduction: Segregation of the viral transforming function and the Herpes Simplex virus tk gene in infectious friend spleen focus-forming virus thymidine kinase vectors

    SciTech Connect

    Joyner, A.L.; Bernstein, A.

    1983-12-01

    A series of deletions and insertions utilizing the herpesvirus thymidine kinase gene (tk) were constructed in the murine retrovirus Friend spleen focus-forming virus (SFFV). In all cases, the coding region for the SFFV-specific glycoprotein (gp55), which is implicated in erythroleukemic transformation, was left intact. These SFFV-TK and SFFV deletion vectors were analyzed for expression of tk and gp55 after DNA-mediated gene transfer. In addition, virus rescued by cotranfection of these vectors with Moloney murine leukemia virus was analyzed for infectious TK-transducing virus, gp55 expression, and erythroleukemia-inducing ability. The experiments demonstrated that deletions or insertions within the intron for the gp55 env gene can interfere with expression of gp55 after both DNA-mediated gene transfer and virus infection. In contrast, the gene transfer efficiency of the tk gene was unaffected in the SFFV-TK vectors, and high-titer infectious TK virus could be recovered. Revertant viruses capable of inducing erythroleukemia and expressing gp55 were generated after cotranfection of the SFFV-TK vectors with murine leukemia virus. The revertant viruses lost both tk sequences and the ability to transduce TK/sup -/ fibroblasts to a TK/sup +/ phenotype. These experiments demonstrate that segregation of the TK and erythroleukemia functions can occur in retrovirus vectors which initially carry both markers.

  11. Clinical Aspects of Feline Retroviruses: A Review

    PubMed Central

    Hartmann, Katrin

    2012-01-01

    Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia), and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less commonly diagnosed than in the previous 20 years; prevalence has been decreasing in most countries. However, FeLV importance may be underestimated as it has been shown that regressively infected cats (that are negative in routinely used FeLV tests) also can develop clinical signs. FIV can cause an acquired immunodeficiency syndrome that increases the risk of opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. This article provides a review of clinical syndromes in progressively and regressively FeLV-infected cats as well as in FIV-infected cats. PMID:23202500

  12. Human Endogenous Retrovirus (HERVK9) Structural Polymorphism With Haplotypic HLA-A Allelic Associations

    PubMed Central

    Kulski, Jerzy K.; Shigenari, Atsuko; Shiina, Takashi; Ota, Masao; Hosomichi, Kazuyoshi; James, Ian; Inoko, Hidetoshi

    2008-01-01

    The frequency and HLA-A allelic associations of a HERVK9 DNA structural polymorphism located in close proximity to the highly polymorphic HLA-A gene within the major histocompatibility complex (MHC) genomic region were determined in Japanese, African Americans, and Australian Caucasians to better understand its human population evolutionary history. The HERVK9 insertion or deletion was detected as a 3′ LTR or a solo LTR, respectively, by separate PCR assays. The average insertion frequency of the HERVK9.HG was significantly different (P < 1.083e−6) between the Japanese (0.59) and the African Americans (0.34) or Australian Caucasians (0.37). LD analysis predicted a highly significant (P < 1.0e−5) linkage between the HLA-A and HERVK9 alleles, probably as a result of hitchhiking (linkage). Evolutionary time estimates of the solo, 5′ and 3′ LTR nucleotide sequence divergences suggest that the HERVK9 was inserted 17.3 MYA with the first structural deletion occurring 15.1 MYA. The LTR/HLA-A haplotypes appear to have been formed mostly during the past 3.9 MY. The HERVK9 insertion and deletion, detected by a simple and economical PCR method, is an informative genetic and evolutionary marker for the study of HLA-A haplotype variations, human migration, the origins of contemporary populations, and the possibility of disease associations. PMID:18757922

  13. Identification of Novel Porcine Endogenous Betaretrovirus Sequences in Miniature Swine

    PubMed Central

    Ericsson, Thomas; Oldmixon, Beth; Blomberg, Jonas; Rosa, Margaret; Patience, Clive; Andersson, Göran

    2001-01-01

    PCR amplification of genomic DNA from miniature swine peripheral blood lymphocytes, using primers corresponding to highly conserved regions of the polymerase (pol) gene, allowed the identification of two novel porcine endogenous retrovirus (PERV) sequences, PMSN-1 and PMSN-4. Phylogenetic analyses of the nucleotide sequences of PMSN-1 and PMSN-4 revealed them to be most closely related to betaretroviruses. The identification of PERVs belonging to the Betaretrovirus genus shows that endogenous retroviruses of this family are more broadly represented in mammalian species than previously appreciated. Both sequences contained inactivating mutations, implying that these particular loci are defective. However, Southern blot analysis showed additional copies of closely related proviruses in the miniature swine genome. Analyses of fetal and adult miniature swine tissues revealed a broad mRNA expression pattern of both PMSN-1 and PMSN-4. The most abundant expression was detected in whole bone marrow c-kit+ (CD117+) progenitor bone marrow cells, fetal liver, salivary gland, and thymus. It appears unlikely that functional loci encoding these novel PERV sequences exist, but this remains to be established. The betaretrovirus sequences described in this report will allow such investigations to be actively pursued. PMID:11222699

  14. An Interleukin-1 Beta-Encoding Retrovirus Exhibits Enhanced Replication In Vivo

    PubMed Central

    2014-01-01

    ABSTRACT Interleukin-1 beta (IL-1β) is an inflammatory cytokine that is secreted in response to inflammasome activation by innate microbe-sensing pathways. Although some retroviruses can trigger IL-1β secretion through the DNA-sensing molecule IFI16, the effect of IL-1β on the course of infection is unknown. To test whether IL-1β secretion affects retroviral replication in vivo, I constructed a novel murine leukemia virus strain (FMLV-IL-1β) that encodes the mature form of IL-1β. This virus replicated with kinetics similar to that of wild-type virus in tissue culture but caused a dramatically more aggressive infection of both C57BL/6 and BALB/c mice. By 7 days postinfection (PI), mice infected with FMLV-IL-1β exhibited splenomegaly and viral loads 300-fold higher than those in mice infected with wild-type FMLV. Furthermore, the enlarged spleens of FMLV-IL-1β-infected mice correlated with a large expansion of Gr-1+ CD11b+ myeloid-derived suppressor cells, as well as elevated levels of immune activation. Although FMLV-IL-1β infection was controlled by C57BL/6 mice by 14 days p.i., FMLV-IL-1β was able to establish a significant persistent infection and immune activation in BALB/c mice. These results demonstrate that IL-1β secretion is a powerful positive regulator of retroviral infection and that FMLV-IL-1β represents a new model of proinflammatory retroviral infection. IMPORTANCE Interleukin-1 beta (IL-1β) is an inflammatory cytokine released in response to activation of innate pathogen-sensing pathways during microbial infection. To examine the potential impact of IL-1β on retroviral replication in vivo, I constructed a novel mouse retrovirus strain (FMLV-IL-1β) that encodes IL-1β and promotes abundant IL-1β secretion from infected cells. This virus replicates with normal kinetics in cultured cells but displays a dramatically enhanced ability to replicate in mice and caused persistent infection and immune activation in the BALB/c strain of mice

  15. The origin and diversity of human retroviruses

    PubMed Central

    Peeters, Martine; D’Arc, Mirela; Delaporte, Eric

    2014-01-01

    Simian immunodeficiency viruses (SIV), T-cell lymphotrophic viruses (STLV), and foamy viruses (SFV) from non-human primates (NHP) have crossed the species barrier to humans at several occasions, leading to the HIV and HTLV epidemic and to sporadic cases of human infections with simian foamy viruses, respectively. Efficient infection and spread in humans differs between SFV, STLV and SIV, but seems also to differ among the different viruses from the same simian lineage, as illustrated by the different spread of HIV-1 M, N O, P or for the different HIV-2 groups. Among the four HIV-1 groups, only HIV-1 group M has spread worldwide and the actual diversity within HIV-1 M (subtypes, Circulating Recombinants) is the result of subsequent evolution and spread in the human population. HIV-2 did only spread to some extent in West Africa, and similarly as for HIV-1, the nine HIV-2 groups have also a different epidemic spread. Four types of HTLV, type 1 to 4, have been described in humans and for 3 of them simian counterparts (STLV-1, STLV-2, STLV-3) have been identified in multiple NHP species. The majority of human infections are with HTLV-1 which is present throughout the world as clusters of high endemicity. Humans are susceptible to a wide variety of SFVs and seem to acquire these viruses more readily than SIVs or STLVs but no signs of disease in humans nor human-to-human transmission of SFV has been documented yet. The current HIV-1 M epidemic illustrates the impact of a single cross-species transmission. The recent discovery of HIV-1 P, HIV-2 I, new HTLV-1 and HTLV-3 variants as well as SFV infections in humans in Central Africa, show that our knowledge of genetic diversity and cross-species transmissions of simian retroviruses are still incomplete. PMID:24584106

  16. Construction and Characterization of an Infectious Molecular Clone of Koala Retrovirus

    PubMed Central

    Shojima, Takayuki; Hoshino, Shigeki; Abe, Masumi; Yasuda, Jiro; Shogen, Hiroko; Kobayashi, Takeshi

    2013-01-01

    Koala retrovirus (KoRV) is a gammaretrovirus that is currently endogenizing into koalas. Studies on KoRV infection have been hampered by the lack of a replication-competent molecular clone. In this study, we constructed an infectious molecular clone, termed plasmid pKoRV522, of a KoRV isolate (strain Aki) from a koala reared in a Japanese zoo. The virus KoRV522, derived from pKoRV522, grew efficiently in human embryonic kidney (HEK293T) cells, attaining 106 focus-forming units/ml. Several mutations in the Gag (L domain) and Env regions reported to be involved in reduction in viral infection/production in vitro are found in pKoRV522, yet KoRV522 replicated well, suggesting that any effects of these mutations are limited. Indeed, a reporter virus pseudotyped with pKoRV522 Env was found to infect human, feline, and mink cell lines efficiently. Analyses of KoRV L-domain mutants showed that an additional PPXY sequence, PPPY, in Gag plays a critical role in KoRV budding. Altogether, our results demonstrate the construction and characterization of the first infectious molecular clone of KoRV. The infectious clone reported here will be useful for elucidating the mechanism of endogenization of the virus in koalas and screening for antiretroviral drugs for KoRV-infected koalas. PMID:23427161

  17. Sequence of retrovirus provirus resembles that of bacterial transposable elements

    NASA Astrophysics Data System (ADS)

    Shimotohno, Kunitada; Mizutani, Satoshi; Temin, Howard M.

    1980-06-01

    The nucleotide sequences of the terminal regions of an infectious integrated retrovirus cloned in the modified λ phage cloning vector Charon 4A have been elucidated. There is a 569-base pair direct repeat at both ends of the viral DNA. The cell-virus junctions at each end consist of a 5-base pair direct repeat of cell DNA next to a 3-base pair inverted repeat of viral DNA. This structure resembles that of a transposable element and is consistent with the protovirus hypothesis that retroviruses evolved from the cell genome.

  18. Endogenous viruses: insights into viral evolution and impact on host biology.

    PubMed

    Feschotte, Cédric; Gilbert, Clément

    2012-04-01

    Recent studies have uncovered myriad viral sequences that are integrated or 'endogenized' in the genomes of various eukaryotes. Surprisingly, it appears that not just retroviruses but almost all types of viruses can become endogenous. We review how these genomic 'fossils' offer fresh insights into the origin, evolutionary dynamics and structural evolution of viruses, which are giving rise to the burgeoning field of palaeovirology. We also examine the multitude of ways through which endogenous viruses have influenced, for better or worse, the biology of their hosts. We argue that the conflict between hosts and viruses has led to the invention and diversification of molecular arsenals, which, in turn, promote the cellular co-option of endogenous viruses. PMID:22421730

  19. Induction of plasmacytomas secreting antigen-specific monoclonal antibodies with a retrovirus expressing v-abl and c-myc.

    PubMed Central

    Weissinger, E M; Mischak, H; Largaespada, D A; Kaehler, D A; Mitchell, T; Smith-Gill, S J; Risser, R; Mushinski, J F

    1991-01-01

    ABL-MYC, a recombinant murine retrovirus that expresses v-abl and c-myc, rapidly induces transplantable mono- or oligoclonal plasmacytomas in BALB/c mice. To determine if the targets for transformation of this retrovirus are antigen-committed B lymphocytes and to explore this system as an alternative technique for producing antigen-specific monoclonal antibodies, plasmacytomas were induced in mice that had been immunized with two different types of immunogens, hen egg white lysozyme and sheep red blood cells. The majority of these plasmacytomas secreted immunogen-specific antibodies. Plasmacytomas induced in unimmunized mice did not react with hen egg white lysozyme or sheep red blood cells. The specific antibodies were comparable in concentration, specificity, and affinity to monoclonal antibodies obtained with conventional hybridoma technology, but, in addition to IgGs and IgMs, they included specific IgA antibodies, which are rare among splenic-derived hybridomas. Our results demonstrate that a principal target for ABL-MYC is an antigen-committed B lymphocyte. In addition this procedure provides an alternative method for the production of monoclonal antibodies, without a requirement for hetero-caryon formation by cell fusion techniques. Images PMID:1924333

  20. Retroviruses Pseudotyped with the Severe Acute Respiratory Syndrome Coronavirus Spike Protein Efficiently Infect Cells Expressing Angiotensin-Converting Enzyme 2

    PubMed Central

    Moore, Michael J.; Dorfman, Tatyana; Li, Wenhui; Wong, Swee Kee; Li, Yanhan; Kuhn, Jens H.; Coderre, James; Vasilieva, Natalya; Han, Zhongchao; Greenough, Thomas C.; Farzan, Michael; Choe, Hyeryun

    2004-01-01

    Infection of receptor-bearing cells by coronaviruses is mediated by their spike (S) proteins. The coronavirus (SARS-CoV) that causes severe acute respiratory syndrome (SARS) infects cells expressing the receptor angiotensin-converting enzyme 2 (ACE2). Here we show that codon optimization of the SARS-CoV S-protein gene substantially enhanced S-protein expression. We also found that two retroviruses, simian immunodeficiency virus (SIV) and murine leukemia virus, both expressing green fluorescent protein and pseudotyped with SARS-CoV S protein or S-protein variants, efficiently infected HEK293T cells stably expressing ACE2. Infection mediated by an S-protein variant whose cytoplasmic domain had been truncated and altered to include a fragment of the cytoplasmic tail of the human immunodeficiency virus type 1 envelope glycoprotein was, in both cases, substantially more efficient than that mediated by wild-type S protein. Using S-protein-pseudotyped SIV, we found that the enzymatic activity of ACE2 made no contribution to S-protein-mediated infection. Finally, we show that a soluble and catalytically inactive form of ACE2 potently blocked infection by S-protein-pseudotyped retrovirus and by SARS-CoV. These results permit studies of SARS-CoV entry inhibitors without the use of live virus and suggest a candidate therapy for SARS. PMID:15367630

  1. PD-L1 Expression on Retrovirus-Infected Cells Mediates Immune Escape from CD8+ T Cell Killing.

    PubMed

    Akhmetzyanova, Ilseyar; Drabczyk, Malgorzata; Neff, C Preston; Gibbert, Kathrin; Dietze, Kirsten K; Werner, Tanja; Liu, Jia; Chen, Lieping; Lang, Karl S; Palmer, Brent E; Dittmer, Ulf; Zelinskyy, Gennadiy

    2015-10-01

    Cytotoxic CD8+ T Lymphocytes (CTL) efficiently control acute virus infections but can become exhausted when a chronic infection develops. Signaling of the inhibitory receptor PD-1 is an important mechanism for the development of virus-specific CD8+ T cell dysfunction. However, it has recently been shown that during the initial phase of infection virus-specific CD8+ T cells express high levels of PD-1, but are fully competent in producing cytokines and killing virus-infected target cells. To better understand the role of the PD-1 signaling pathway in CD8+ T cell cytotoxicity during acute viral infections we analyzed the expression of the ligand on retrovirus-infected cells targeted by CTLs. We observed increased levels of PD-L1 expression after infection of cells with the murine Friend retrovirus (FV) or with HIV. In FV infected mice, virus-specific CTLs efficiently eliminated infected target cells that expressed low levels of PD-L1 or that were deficient for PD-L1 but the population of PD-L1high cells escaped elimination and formed a reservoir for chronic FV replication. Infected cells with high PD-L1 expression mediated a negative feedback on CD8+ T cells and inhibited their expansion and cytotoxic functions. These findings provide evidence for a novel immune escape mechanism during acute retroviral infection based on PD-L1 expression levels on virus infected target cells. PMID:26484769

  2. PD-L1 Expression on Retrovirus-Infected Cells Mediates Immune Escape from CD8+ T Cell Killing

    PubMed Central

    Neff, C. Preston; Gibbert, Kathrin; Dietze, Kirsten K.; Werner, Tanja; Liu, Jia; Chen, Lieping; Lang, Karl S.; Palmer, Brent E.; Dittmer, Ulf; Zelinskyy, Gennadiy

    2015-01-01

    Cytotoxic CD8+ T Lymphocytes (CTL) efficiently control acute virus infections but can become exhausted when a chronic infection develops. Signaling of the inhibitory receptor PD-1 is an important mechanism for the development of virus-specific CD8+ T cell dysfunction. However, it has recently been shown that during the initial phase of infection virus-specific CD8+ T cells express high levels of PD-1, but are fully competent in producing cytokines and killing virus-infected target cells. To better understand the role of the PD-1 signaling pathway in CD8+ T cell cytotoxicity during acute viral infections we analyzed the expression of the ligand on retrovirus-infected cells targeted by CTLs. We observed increased levels of PD-L1 expression after infection of cells with the murine Friend retrovirus (FV) or with HIV. In FV infected mice, virus-specific CTLs efficiently eliminated infected target cells that expressed low levels of PD-L1 or that were deficient for PD-L1 but the population of PD-L1high cells escaped elimination and formed a reservoir for chronic FV replication. Infected cells with high PD-L1 expression mediated a negative feedback on CD8+ T cells and inhibited their expansion and cytotoxic functions. These findings provide evidence for a novel immune escape mechanism during acute retroviral infection based on PD-L1 expression levels on virus infected target cells. PMID:26484769

  3. Evolutionary Relationships among Extinct and Extant Sloths: The Evidence of Mitogenomes and Retroviruses.

    PubMed

    Slater, Graham J; Cui, Pin; Forasiepi, Analía M; Lenz, Dorina; Tsangaras, Kyriakos; Voirin, Bryson; de Moraes-Barros, Nadia; MacPhee, Ross D E; Greenwood, Alex D

    2016-03-01

    Macroevolutionary trends exhibited by retroviruses are complex and not entirely understood. The sloth endogenized foamy-like retrovirus (SloEFV), which demonstrates incongruence in virus-host evolution among extant sloths (Order Folivora), has not been investigated heretofore in any extinct sloth lineages and its premodern history within folivorans is therefore unknown. Determining retroviral coevolutionary trends requires a robust phylogeny of the viral host, but the highly reduced modern sloth fauna (6 species in 2 genera) does not adequately represent what was once a highly diversified clade (∼100 genera) of placental mammals. At present, the amount of molecular data available for extinct sloth taxa is limited, and analytical results based on these data tend to conflict with phylogenetic inferences made on the basis of morphological studies. To augment the molecular data set, we applied hybridization capture and next-generation Illumina sequencing to two extinct and three extant sloth species to retrieve full mitochondrial genomes (mitogenomes) from the hosts and the polymerase gene of SloEFV. The results produced a fully resolved and well-supported phylogeny that supports dividing crown families into two major clades: 1) The three-toed sloth, Bradypus, and Nothrotheriidae and 2) Megalonychidae, including the two-toed sloth, Choloepus, and Mylodontidae. Our calibrated time tree indicates that the Miocene epoch (23.5 Ma), particularly its earlier part, was an important interval for folivoran diversification. Both extant and extinct sloths demonstrate multiple complex invasions of SloEFV into the ancestral sloth germline followed by subsequent introgressions across different sloth lineages. Thus, sloth mitogenome and SloEFV evolution occurred separately and in parallel among sloths. PMID:26878870

  4. Evolutionary Relationships among Extinct and Extant Sloths: The Evidence of Mitogenomes and Retroviruses

    PubMed Central

    Slater, Graham J.; Cui, Pin; Forasiepi, Analía M.; Lenz, Dorina; Tsangaras, Kyriakos; Voirin, Bryson; de Moraes-Barros, Nadia; MacPhee, Ross D. E.; Greenwood, Alex D.

    2016-01-01

    Macroevolutionary trends exhibited by retroviruses are complex and not entirely understood. The sloth endogenized foamy-like retrovirus (SloEFV), which demonstrates incongruence in virus–host evolution among extant sloths (Order Folivora), has not been investigated heretofore in any extinct sloth lineages and its premodern history within folivorans is therefore unknown. Determining retroviral coevolutionary trends requires a robust phylogeny of the viral host, but the highly reduced modern sloth fauna (6 species in 2 genera) does not adequately represent what was once a highly diversified clade (∼100 genera) of placental mammals. At present, the amount of molecular data available for extinct sloth taxa is limited, and analytical results based on these data tend to conflict with phylogenetic inferences made on the basis of morphological studies. To augment the molecular data set, we applied hybridization capture and next-generation Illumina sequencing to two extinct and three extant sloth species to retrieve full mitochondrial genomes (mitogenomes) from the hosts and the polymerase gene of SloEFV. The results produced a fully resolved and well-supported phylogeny that supports dividing crown families into two major clades: 1) The three-toed sloth, Bradypus, and Nothrotheriidae and 2) Megalonychidae, including the two-toed sloth, Choloepus, and Mylodontidae. Our calibrated time tree indicates that the Miocene epoch (23.5 Ma), particularly its earlier part, was an important interval for folivoran diversification. Both extant and extinct sloths demonstrate multiple complex invasions of SloEFV into the ancestral sloth germline followed by subsequent introgressions across different sloth lineages. Thus, sloth mitogenome and SloEFV evolution occurred separately and in parallel among sloths. PMID:26878870

  5. Complete nucleotide sequence and transcriptional analysis of snakehead fish retrovirus.

    PubMed Central

    Hart, D; Frerichs, G N; Rambaut, A; Onions, D E

    1996-01-01

    The complete genome of the snakehead fish retrovirus has been cloned and sequenced, and its transcriptional profile in cell culture has been determined. The 11.2-kb provirus displays a complex expression pattern capable of encoding accessory proteins and is unique in the predicted location of the env initiation codon and signal peptide upstream of gag and the common splice donor site. The virus is distinguishable from all known retrovirus groups by the presence of an arginine tRNA primer binding site. The coding regions are highly divergent and show a number of unusual characteristics, including a large Gag coiled-coil region, a Pol domain of unknown function, and a long, lentiviral-like, Env cytoplasmic domain. Phylogenetic analysis of the Pol sequence emphasizes the divergent nature of the virus from the avian and mammalian retroviruses. The snakehead virus is also distinct from a previously characterized complex fish retrovirus, suggesting that discrete groups of these viruses have yet to be identified in the lower vertebrates. PMID:8648695

  6. An elastic model of partial budding of retroviruses

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Nguyen, Toan

    2008-03-01

    Retroviruses are characterized by their unique infection strategy of reverse transcription, in which the genetic information flows from RNA back to DNA. The most well known representative is the human immunodeficiency virus (HIV). Unlike budding of traditional enveloped viruses, retrovirus budding happens together with the formation of spherical virus capsids at the cell membrane. Led by this unique budding mechanism, we proposed an elastic model of retrovirus budding in this work. We found that if the lipid molecules of the membrane are supplied fast enough from the cell interior, the budding always proceeds to completion. In the opposite limit, there is an optimal size of partially budded virions. The zenith angle of these partially spherical capsids, α, is given by α˜(2̂/κσ)^1/4, where κ is the bending modulus of the membrane, σ is the surface tension of the membrane, and τ characterizes the strength of capsid protein interaction. If τ is large enough such that α˜π, the budding is complete. Our model explained many features of retrovirus partial budding observed in experiments.

  7. An Endogenous Foamy-like Viral Element in the Coelacanth Genome

    PubMed Central

    Han, Guan-Zhu; Worobey, Michael

    2012-01-01

    Little is known about the origin and long-term evolutionary mode of retroviruses. Retroviruses can integrate into their hosts' genomes, providing a molecular fossil record for studying their deep history. Here we report the discovery of an endogenous foamy virus-like element, which we designate ‘coelacanth endogenous foamy-like virus’ (CoeEFV), within the genome of the coelacanth (Latimeria chalumnae). Phylogenetic analyses place CoeEFV basal to all known foamy viruses, strongly suggesting an ancient ocean origin of this major retroviral lineage, which had previously been known to infect only land mammals. The discovery of CoeEFV reveals the presence of foamy-like viruses in species outside the Mammalia. We show that foamy-like viruses have likely codiverged with their vertebrate hosts for more than 407 million years and underwent an evolutionary transition from water to land with their vertebrate hosts. These findings suggest an ancient marine origin of retroviruses and have important implications in understanding foamy virus biology. PMID:22761578

  8. A historical reflection on the discovery of human retroviruses

    PubMed Central

    Vahlne, Anders

    2009-01-01

    The discovery of HIV-1 as the cause of AIDS was one of the major scientific achievements during the last century. Here the events leading to this discovery are reviewed with particular attention to priority and actual contributions by those involved. Since I would argue that discovering HIV was dependent on the previous discovery of the first human retrovirus HTLV-I, the history of this discovery is also re-examined. The first human retroviruses (HTLV-I) was first reported by Robert C. Gallo and coworkers in 1980 and reconfirmed by Yorio Hinuma and coworkers in 1981. These discoveries were in turn dependent on the previous discovery by Gallo and coworkers in 1976 of interleukin 2 or T-cell growth factor as it was called then. HTLV-II was described by Gallo's group in 1982. A human retrovirus distinct from HTLV-I and HTLV-II in that it was shown to have the morphology of a lentivirus was in my mind described for the first time by Luc Montagnier in an oral presentation at Cold Spring Harbor in September of 1983. This virus was isolated from a patient with lymphadenopathy using the protocol previously described for HTLV by Gallo. The first peer reviewed paper by Montagnier's group of such a retrovirus, isolated from two siblings of whom one with AIDS, appeared in Lancet in April of 1984. However, the proof that a new human retrovirus (HIV-1) was the cause of AIDS was first established in four publications by Gallo's group in the May 4th issue of Science in 1984. PMID:19409074

  9. Inhibition of Borna disease virus replication by an endogenous bornavirus-like element in the ground squirrel genome.

    PubMed

    Fujino, Kan; Horie, Masayuki; Honda, Tomoyuki; Merriman, Dana K; Tomonaga, Keizo

    2014-09-01

    Animal genomes contain endogenous viral sequences, such as endogenous retroviruses and retrotransposons. Recently, we and others discovered that nonretroviral viruses also have been endogenized in many vertebrate genomes. Bornaviruses belong to the Mononegavirales and have left endogenous fragments, called "endogenous bornavirus-like elements" (EBLs), in the genomes of many mammals. The striking features of EBLs are that they contain relatively long ORFs which have high sequence homology to the extant bornavirus proteins. Furthermore, some EBLs derived from bornavirus nucleoprotein (EBLNs) have been shown to be transcribed as mRNA and probably are translated into proteins. These features lead us to speculate that EBLs may function as cellular coopted genes. An EBLN element in the genome of the thirteen-lined ground squirrel (Ictidomys tridecemlineatus), itEBLN, encodes an ORF with 77% amino acid sequence identity to the current bornavirus nucleoprotein. In this study, we cloned itEBLN from the ground squirrel genome and investigated its involvement in Borna disease virus (BDV) replication. Interestingly, itEBLN, but not a human EBLN, colocalized with the viral factory in the nucleus and appeared to affect BDV polymerase activity by being incorporated into the viral ribonucleoprotein. Our data show that, as do certain endogenous retroviruses, itEBLN potentially may inhibit infection by related exogenous viruses in vivo. PMID:25157155

  10. The National Heart, Lung, and Blood Institute retrovirus epidemiology donor studies (Retrovirus Epidemiology Donor Study and Retrovirus Epidemiology Donor Study-II): twenty years of research to advance blood product safety and availability.

    PubMed

    Kleinman, Steven; King, Melissa R; Busch, Michael P; Murphy, Edward L; Glynn, Simone A

    2012-10-01

    The Retrovirus Epidemiology Donor Study (REDS), conducted from 1989 to 2001, and the REDS-II, conducted from 2004 to 2012, were National Heart, Lung, and Blood Institute-funded, multicenter programs focused on improving blood safety and availability in the United States. The REDS-II also included international study sites in Brazil and China. The 3 major research domains of REDS/REDS-II have been infectious disease risk evaluation, blood donation availability, and blood donor characterization. Both programs have made significant contributions to transfusion medicine research methodology by the use of mathematical modeling, large-scale donor surveys, innovative methods of repository sample storage, and establishing an infrastructure that responded to potential emerging blood safety threats such as xenotropic murine leukemia virus-related virus. Blood safety studies have included protocols evaluating epidemiologic and/or laboratory aspects of human immunodeficiency virus, human T-lymphotropic virus 1/2, hepatitis C virus, hepatitis B virus, West Nile virus, cytomegalovirus, human herpesvirus 8, parvovirus B19, malaria, Creutzfeldt-Jakob disease, influenza, and Trypanosoma cruzi infections. Other analyses have characterized blood donor demographics, motivations to donate, factors influencing donor return, behavioral risk factors, donors' perception of the blood donation screening process, and aspects of donor deferral. In REDS-II, 2 large-scale blood donor protocols examined iron deficiency in donors and the prevalence of leukocyte antibodies. This review describes the major study results from over 150 peer-reviewed articles published by these 2 REDS programs. In 2011, a new 7-year program, the Recipient Epidemiology and Donor Evaluation Study-III, was launched. The Recipient Epidemiology and Donor Evaluation Study-III expands beyond donor-based research to include studies of blood transfusion recipients in the hospital setting and adds a third country, South Africa

  11. Tracking interspecies transmission and long-term evolution of an ancient retrovirus using the genomes of modern mammals

    PubMed Central

    Diehl, William E; Patel, Nirali; Halm, Kate; Johnson, Welkin E

    2016-01-01

    Mammalian genomes typically contain hundreds of thousands of endogenous retroviruses (ERVs), derived from ancient retroviral infections. Using this molecular 'fossil' record, we reconstructed the natural history of a specific retrovirus lineage (ERV-Fc) that disseminated widely between ~33 and ~15 million years ago, corresponding to the Oligocene and early Miocene epochs. Intercontinental viral spread, numerous instances of interspecies transmission and emergence in hosts representing at least 11 mammalian orders, and a significant role for recombination in diversification of this viral lineage were also revealed. By reconstructing the canonical retroviral genes, we identified patterns of adaptation consistent with selection to maintain essential viral protein functions. Our results demonstrate the unique potential of the ERV fossil record for studying the processes of viral spread and emergence as they play out across macro-evolutionary timescales, such that looking back in time may prove insightful for predicting the long-term consequences of newly emerging viral infections. DOI: http://dx.doi.org/10.7554/eLife.12704.001 PMID:26952212

  12. Expression of the Drosophila retrovirus gypsy as ultrastructurally detectable particles in the ovaries of flies carrying a permissive flamenco allele.

    PubMed

    Lécher, P; Bucheton, A; Pélisson, A

    1997-09-01

    The endogenous retrovirus gypsy is controlled by the Drosophila gene flamenco (flam). New insertions of gypsy occur in any individual Drosophila if its mother is homozygous for the flam1 permissive allele and contains functional gypsy proviruses. The ovaries of flam1 females also contain high amounts of gypsy RNAs. Unexpectedly however, gypsy derepression does not occur in the flam1 female germ-line proper but in the somatic follicular epithelium of the ovary. Since extracts from these females are able to efficiently infect the germ-line of a strain devoid of active gypsy proviruses, we assume that a similar kind of germ-line infection, which would occur inside the flam1 females themselves, could be required for gypsy insertions to occur in their progeny. This hypothesis was confirmed by electron microscopy observations showing that non-enveloped intracytoplasmic particles containing gypsy RNAs accumulate in the apical region of the flam1 follicle cells, close to specific membrane domains to which the gypsy envelope proteins are targeted, whereas both are absent in the flam+ controls. Low amounts of similar virus-like particles were also observed in flam1 oocytes, but it is not yet known whether they entered passively or as a result of membrane fusion. This is the first report of the beginning of a retrovirus cycle in invertebrates and these observations should be taken into account when explaining the maternal effect of the flamenco gene on the multiplication of gypsy proviruses. PMID:9292028

  13. Endogenous Pyrogen Physiology.

    ERIC Educational Resources Information Center

    Beisel, William R.

    1980-01-01

    Discusses the physiology of endogenous pyrogen (EP), the fever-producing factor of cellular origin. Included are: its hormone-like role, its molecular nature, bioassay procedures, cellular production and mechanisms of EP action. (SA)

  14. Dimer linkage structure in retroviruses: models that include both duplex and quadruplex domains.

    PubMed

    Zarudnaya, M I; Kolomiets, I M; Potyahaylo, A L; Hovorun, D M

    2005-01-01

    Genome of all known retroviruses consists of two identical molecules of RNA, which are non-covalently linked. The most stable contact site between two RNA molecules is located near their 5' ends. The molecular interactions in the dimer linkage structure (DLS) in mature virions are currently unknown. Recently we suggested that the dimer linkage structure in human immunodeficiency virus 1 (HIV-1) contains both duplex and quadruplex domains and proposed a model of DLS in HIV-1Mal (Central African virus). In this paper we showed that similar models can be also built for HIV- 1Lai, a representative of the North-American and European viruses. One of the double-stranded domains in the model structures represents either an extended duplex formed by different pathways (through base pair melting and subsequent reannealing or by a recombination mechanism) or kissing loop complex. The quadruplexes contain both G- and mixed tetrads, for example, G.C.G.C or A.U.A.U. Phylogenetic analysis of 350 isolates from NCBI database showed that similar models of DLS are predictable practically for all HIV-1 isolates surveyed. A model of dimer linkage structure in Moloney murine sarcoma virus (MuSV) is also presented. The structure includes a duplex formed by the palindromic sequences and several quadruplexes. PMID:16335231

  15. Escape from R-peptide deletion in a {gamma}-retrovirus

    SciTech Connect

    Schneider, Irene C.; Eckhardt, Manon; Brynza, Julia; Collins, Mary K.; Cichutek, Klaus; Buchholz, Christian J.

    2011-09-30

    The R peptide in the cytoplasmic tail (C-tail) of {gamma}-retroviral envelope proteins (Env) prevents membrane fusion before budding. To analyse its role in the formation of replication competent, infectious particles, we developed chimeric murine leukaemia viruses (MLV) with unmodified or R-peptide deleted Env proteins of the gibbon ape leukaemia virus (GaLV). While titres of these viruses were unaffected, R-peptide deficiency led to strongly impaired spreading. Most remarkably, we isolated an escape mutant which had restored an open reading frame for a C-terminal extension of the truncated C-tail. A reconstituted virus encoding this escape C-tail replicated in cell culture. In contrast to R-peptide deficient Env, particle incorporation of the escape Env was effective due to an enhanced protein expression and restored intracellular co-localisation with Gag proteins. Our data demonstrate that the R peptide not only regulates membrane fusion but also mediates efficient Env protein particle incorporation in {gamma}-retrovirus infected cells.

  16. Retrovirus-induced insertional mutagenesis: mechanism of collagen mutation in Mov13 mice.

    PubMed Central

    Barker, D D; Wu, H; Hartung, S; Breindl, M; Jaenisch, R

    1991-01-01

    The Mov13 mouse strain carries a mutation in the alpha 1(I) procollagen gene which is due to the insertion of a Moloney murine leukemia provirus into the first intron. This insertion results in the de novo methylation of the provirus and flanking DNA, the alteration of chromatin structure, and the transcriptional inactivity of the collagen promoter. To address the mechanism of mutagenesis, we reintroduced a cloned and therefore demethylated version of the Mov13 mutant allele into mouse fibroblasts. The transfected gene was not transcribed, indicating that the transcriptional defect was not due to the hypermethylation. Rather, this result strongly suggests that the mutation is due to the displacement or disruption of cis-acting regulatory DNA sequences within the first intron. We also constructed a Mov13 variant allele containing a single long terminal repeat instead of the whole provirus. This construct also failed to express mRNA, indicating that the Mov13 mutation does not revert by provirus excision as has been observed for other retrovirus-induced mutations. Images PMID:1922037

  17. Bacillus cereus endogenous panophthalmitis.

    PubMed

    Bouza, E; Grant, S; Jordan, C; Yook, R H; Sulit, H L

    1979-03-01

    A case of severe suppurative endogenous panophthalmitis caused by Bacillus cereus resulted from intravenously administered medications. This is the first, to our knowledge, well-documented case of endogenous endophthalmitis associated with this organism. It is recommended that if on Gram's stain of the anterior chamber fluid, Gram-positive rods are seen, chloramphenicol should be administered in addition to penicillin because of the possibility of B cereus infection. PMID:105693

  18. Annotation and visualization of endogenous retroviral sequences using the Distributed Annotation System (DAS) and eBioX

    PubMed Central

    Martínez Barrio, Álvaro; Lagercrantz, Erik; Sperber, Göran O; Blomberg, Jonas; Bongcam-Rudloff, Erik

    2009-01-01

    Background The Distributed Annotation System (DAS) is a widely used network protocol for sharing biological information. The distributed aspects of the protocol enable the use of various reference and annotation servers for connecting biological sequence data to pertinent annotations in order to depict an integrated view of the data for the final user. Results An annotation server has been devised to provide information about the endogenous retroviruses detected and annotated by a specialized in silico tool called RetroTector. We describe the procedure to implement the DAS 1.5 protocol commands necessary for constructing the DAS annotation server. We use our server to exemplify those steps. Data distribution is kept separated from visualization which is carried out by eBioX, an easy to use open source program incorporating multiple bioinformatics utilities. Some well characterized endogenous retroviruses are shown in two different DAS clients. A rapid analysis of areas free from retroviral insertions could be facilitated by our annotations. Conclusion The DAS protocol has shown to be advantageous in the distribution of endogenous retrovirus data. The distributed nature of the protocol is also found to aid in combining annotation and visualization along a genome in order to enhance the understanding of ERV contribution to its evolution. Reference and annotation servers are conjointly used by eBioX to provide visualization of ERV annotations as well as other data sources. Our DAS data source can be found in the central public DAS service repository, , or at . PMID:19534743

  19. Retroviruses 2004: Review of the 2004 Cold Spring Harbor Retroviruses conference

    PubMed Central

    Freed, Eric O; Ross, Susan R

    2004-01-01

    For the past several decades, retrovirologists from around the world have gathered in late May at the Cold Spring Harbor Laboratories in New York to present their studies in formal talks and posters, and to discuss their ongoing research informally at the bar or on the beach. As organizers of the 2004 Cold Spring Harbor Retroviruses Conference, we have been asked by the editors of Retrovirology to prepare a review of the meeting for publication on-line. Our goal in this review is not to provide a detailed description of data presented at the meeting but rather to highlight some of the significant developments reported this year. The review is structured in a manner that parallels the organization of the meeting; beginning with the entry phase of the replication cycle, proceeding with post-entry events, assembly and release, integration, reverse transcription, pathogenesis/host factors, RNA-related events (transcription, processing, export, and packaging) and finishing with antivirals. While the most striking developments this year involved post-entry events and assembly/release, significant progress was made towards elucidating a number of aspects of the retroviral replication cycle. PMID:15357866

  20. Vaccination against δ-retroviruses: the bovine leukemia virus paradigm.

    PubMed

    Gutiérrez, Gerónimo; Rodríguez, Sabrina M; de Brogniez, Alix; Gillet, Nicolas; Golime, Ramarao; Burny, Arsène; Jaworski, Juan-Pablo; Alvarez, Irene; Vagnoni, Lucas; Trono, Karina; Willems, Luc

    2014-06-01

    Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related d-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly in subtropical areas. HTLV-1 induces a wide spectrum of diseases (e.g., HTLV-associated myelopathy/tropical spastic paraparesis) and leukemia/lymphoma (adult T-cell leukemia). Bovine leukemia virus is a major pathogen of cattle, causing important economic losses due to a reduction in production, export limitations and lymphoma-associated death. In the absence of satisfactory treatment for these diseases and besides the prevention of transmission, the best option to reduce the prevalence of d-retroviruses is vaccination. Here, we provide an overview of the different vaccination strategies in the BLV model and outline key parameters required for vaccine efficacy. PMID:24956179

  1. The Endogenous Exposome

    PubMed Central

    Nakamura, Jun; Mutlu, Esra; Sharma, Vyom; Collins, Leonard; Bodnar, Wanda; Yu, Rui; Lai, Yongquan; Moeller, Benjamin; Lu, Kun; Swenberg, James

    2014-01-01

    The concept of the Exposome, is a compilation of diseases and one’s lifetime exposure to chemicals, whether the exposure comes from environmental, dietary, or occupational exposures; or endogenous chemicals that are formed from normal metabolism, inflammation, oxidative stress, lipid peroxidation, infections, and other natural metabolic processes such as alteration of the gut microbiome. In this review, we have focused on the Endogenous Exposome, the DNA damage that arises from the production of endogenous electrophilic molecules in our cells. It provides quantitative data on endogenous DNA damage and its relationship to mutagenesis, with emphasis on when exogenous chemical exposures that produce identical DNA adducts to those arising from normal metabolism cause significant increases in total identical DNA adducts. We have utilized stable isotope labeled chemical exposures of animals and cells, so that accurate relationships between endogenous and exogenous exposures can be determined. Advances in mass spectrometry have vastly increased both the sensitivity and accuracy of such studies. Furthermore, we have clear evidence of which sources of exposure drive low dose biology that results in mutations and disease. These data provide much needed information to impact quantitative risk assessments, in the hope of moving towards the use of science, rather than default assumptions. PMID:24767943

  2. Apparatus for testing for infection by a retrovirus

    DOEpatents

    Layne, Scott P.; Beugelsdijk, Tony J.

    1999-01-01

    An apparatus for testing specimens for infection by a retrovirus is described. The apparatus comprises a process controller including a communications module for translating user commands into test instrument suite commands and a means for communicating specimen test results to a user. The apparatus further comprises a test instrument suite including a means for treating the specimen to manifest an observable result and a detector for measuring the observable result.

  3. Differences in lymphomagenic properties of AKR mouse retroviruses.

    PubMed

    Hays, E F; Levy, J A

    1984-10-15

    Long-term studies on lymphomagenicity of several AKR mouse retroviruses have shown that the biologically cloned ecotropic SL3-3c virus is the most lymphomagenic of all viruses tested. This fact was demonstrated by lymphomagenicity in five mouse strains SJL, C3Hf/Bi, C3H/HeJ, CBA/H, and NFS, and lymphoma acceleration in AKR mice. The incidence was higher and latent periods shorter than that found with the other retroviruses tested (SL3-1c, SL3-2c, MCFc, and GMuLVc). In addition, it was the only retrovirus found to be highly oncogenic in the C3H/HeJ and CBA/H strains. Lack of lymphomagenicity of MCFc in CBA/H strain was shown to be due to a block in viral replication. Addition of nononcogenic Akv ecotropic virus did not affect this lack of oncogenicity. The lymphomas developing in CBA/H and SJL mice after neonatal inoculation of SL3-3c virus only produced lymphomagenic ecotropic virus. Thus, SL3-3c lymphomagenesis is most likely due solely to the action of that virus. These studies indicate that pure ecotropic AKR viruses can be highly leukemogenic. PMID:6093361

  4. A Computational Model for Predicting RNase H Domain of Retrovirus.

    PubMed

    Wu, Sijia; Zhang, Xinman; Han, Jiuqiang

    2016-01-01

    RNase H (RNH) is a pivotal domain in retrovirus to cleave the DNA-RNA hybrid for continuing retroviral replication. The crucial role indicates that RNH is a promising drug target for therapeutic intervention. However, annotated RNHs in UniProtKB database have still been insufficient for a good understanding of their statistical characteristics so far. In this work, a computational RNH model was proposed to annotate new putative RNHs (np-RNHs) in the retroviruses. It basically predicts RNH domains through recognizing their start and end sites separately with SVM method. The classification accuracy rates are 100%, 99.01% and 97.52% respectively corresponding to jack-knife, 10-fold cross-validation and 5-fold cross-validation test. Subsequently, this model discovered 14,033 np-RNHs after scanning sequences without RNH annotations. All these predicted np-RNHs and annotated RNHs were employed to analyze the length, hydrophobicity and evolutionary relationship of RNH domains. They are all related to retroviral genera, which validates the classification of retroviruses to a certain degree. In the end, a software tool was designed for the application of our prediction model. The software together with datasets involved in this paper can be available for free download at https://sourceforge.net/projects/rhtool/files/?source=navbar. PMID:27574780

  5. Co-infection with the friend retrovirus and mouse scrapie does not alter prion disease pathogenesis in susceptible mice.

    PubMed

    Leblanc, Pascal; Hasenkrug, Kim; Ward, Anne; Myers, Lara; Messer, Ronald J; Alais, Sandrine; Timmes, Andrew; Priola, Suzette A; Priola, Sue

    2012-01-01

    Prion diseases are fatal, transmissible neurodegenerative diseases of the central nervous system. An abnormally protease-resistant and insoluble form (PrP(Sc)) of the normally soluble protease-sensitive host prion protein (PrP(C)) is the major component of the infectious prion. During the course of prion disease, PrP(Sc) accumulates primarily in the lymphoreticular and central nervous systems. Recent studies have shown that co-infection of prion-infected fibroblast cells with the Moloney murine leukemia virus (Mo-MuLV) strongly enhanced the release and spread of scrapie infectivity in cell culture, suggesting that retroviral coinfection might significantly influence prion spread and disease incubation times in vivo. We now show that another retrovirus, the murine leukemia virus Friend (F-MuLV), also enhanced the release and spread of scrapie infectivity in cell culture. However, peripheral co-infection of mice with both Friend virus and the mouse scrapie strain 22L did not alter scrapie disease incubation times, the levels of PrP(Sc) in the brain or spleen, or the distribution of pathological lesions in the brain. Thus, retroviral co-infection does not necessarily alter prion disease pathogenesis in vivo, most likely because of different cell-specific sites of replication for scrapie and F-MuLV. PMID:22295118

  6. Endogenous opioids and reward.

    PubMed

    Van Ree, J M; Niesink, R J; Van Wolfswinkel, L; Ramsey, N F; Kornet, M M; Van Furth, W R; Vanderschuren, L J; Gerrits, M A; Van den Berg, C L

    2000-09-29

    The discovery of endogenous opioids has markedly influenced the research on the biology of addiction and reward brain processes. Evidence has been presented that these brain substances modulate brain stimulation reward, self-administration of different drugs of abuse, sexual behaviour and social behaviour. There appears to be two different domains in which endogenous opioids, present in separate and distinct brain regions, are involved. One is related to the modulation of incentive motivational processes and the other to the performance of certain behaviours. It is concluded that endogenous opioids may play a role in the vulnerability to certain diseases, such as addiction and autism, but also when the disease is present, such as alcoholism. PMID:11033317

  7. Drawing a fine line on endogenous retroelement activity

    PubMed Central

    Castro-Diaz, Nathaly; Friedli, Marc; Trono, Didier

    2015-01-01

    Endogenous retroelements (EREs) are essential motors of evolution yet require careful control to prevent genomic catastrophes, notably during the vulnerable phases of epigenetic reprogramming that occur immediately after fertilization and in germ cells. Accordingly, a variety of mechanisms restrict these mobile genetic units. Previous studies have revealed the importance of KRAB-containing zinc finger proteins (KRAB-ZFPs) and their cofactor, KAP1, in the early embryonic silencing of endogenous retroviruses and so-called SVAs, but the implication of this transcriptional repression system in the control of LINE-1, the only known active autonomous retrotransposon in the human genome, was thought to be marginal. Two recent studies straighten the record by revealing that the KRAB/KAP system is key to the control of L1 in embryonic stem (ES) cells, and go further in demonstrating that DNA methylation and KRAB/KAP1-induced repression contribute to this process in an evolutionally dynamic fashion. These results shed light on the delicate equilibrium between higher vertebrates and endogenous retroelements, which are not just genetic invaders calling for strict control but rather a constantly renewed and nicely exploitable source of evolutionary potential. PMID:26442176

  8. [Epidemiology, origin and genetic diversity of HTLV-1 retrovirus and STLV-1 simian affiliated retrovirus].

    PubMed

    Gessain, A; Mahieux, R

    2000-07-01

    Human T Cell leukemia/lymphoma virus type I, the first human oncogenic retrovirus, is the aetiological factor of Adult T cell leukemia (ATL), a CD4+ malignant lymphoproliferative disease and of a chronic neuromyelopathy, the tropical spastic paraparesis or HTLV-1 associated myelopathy (TSP/HAM). HTLV-1, which infects from 15 to 25 million individuals world-wide, is highly endemic in certain areas such as south-western Japan, Central Africa, the Caribbean basin and some regions of South America, Melanesia and of the middle East (for example the Mashhad area of Iran). The three major modes of transmission for HTLV-1 infection are perinatal, sexual and by blood transfusion. Recent molecular studies on HTLV-1 have shown the existence of several molecular subtypes (genotypes). These are related to the geographical origin of the infected populations and not to the associated diseases. The virus has a very high genetic stability. Viral amplification via clonal expansion of infected cells, rather than by use of reverse transcription could explain this remarkable phenomenon which can be used as a molecular tool for gaining new insights into the origin, evolution and modes of dissemination of HTLV-1. Analyses of HTLV-1 and STLV-1 (the simian counterpart) viral strains from throughout the world suggest that four events are responsible for this pattern of dissemination: 1) the transmission in the wild of STLV-1 between simian species, 2) the transmission of STLV-1 to humans as exemplified by the high percentage of identity between STLV-1 strains from chimpanzees or from mandrills with some HTLV-1 strains present in inhabitants of Central Africa, 3) persistence of HTLV-1 over a long period of time (by sexual and perinatal transmissions) in remote populations, as seen in the Australo-Melanesian region and 4) a global distribution of HTLV-1 via large scale human migrations, e.g., the slave trade from Africa to the New World. PMID:11030050

  9. The relationship between the flamenco gene and gypsy in Drosophila: how to tame a retrovirus.

    PubMed

    Bucheton, A

    1995-09-01

    For a long time, retroviruses have been considered to be restricted to vertebrates. However, the genome of insects contains elements like gypsy in Drosophila melanogaster that are strikingly similar to vertebrate proviruses of retroviruses, which were considered to be transposable elements. Recent results indicate that gypsy has infective properties and is therefore a retrovirus, the first to be identified in invertebrates. It is normally repressed by a host gene called flamenco, which apparently controls the transposition and infective properties of gypsy. This provides an exceptional experimental model to investigate the genetic relationships between retroviruses and their hosts. PMID:7482786

  10. The flamenco locus controls the gypsy and ZAM retroviruses and is required for Drosophila oogenesis.

    PubMed

    Mével-Ninio, Maryvonne; Pelisson, Alain; Kinder, Jennifer; Campos, Ana Regina; Bucheton, Alain

    2007-04-01

    In Drosophila, the as yet uncloned heterochromatic locus flamenco (flam) controls mobilization of the endogenous retrovirus gypsy through the repeat-associated small interfering (rasi) RNA silencing pathway. Restrictive alleles (flamR) downregulate accumulation of gypsy transcripts in the somatic follicular epithelium of the ovary. In contrast, permissive alleles (flamP) are unable to repress gypsy. DIP1, the closest transcription unit to a flam-insertional mutation, was considered as a good candidate to be a gypsy regulator, since it encodes a dsRNA-binding protein. To further characterize the locus we analyzed P-induced flam mutants and generated new mutations by transposon mobilization. We show that flam is required somatically for morphogenesis of the follicular epithelium, the tissue where gypsy is repressed. This developmental activity is necessary to control gypsy and another retroelement, ZAM. We also show that flam is not DIP1, as none of the new permissive mutants affect the DIP1 coding sequence. In addition, two deletions removing DIP1 coding sequences do not affect any of the flamenco functions. Our results suggest that flamenco extends proximally to DIP1, spanning >130 kb of transposon-rich heterochromatin. We propose a model explaining the multiple functions of this large heterochromatic locus. PMID:17277359

  11. Characterization of the fusion core in zebrafish endogenous retroviral envelope protein

    SciTech Connect

    Shi, Jian; Zhang, Huaidong; Gong, Rui; Xiao, Gengfu

    2015-05-08

    Zebrafish endogenous retrovirus (ZFERV) is the unique endogenous retrovirus in zebrafish, as yet, containing intact open reading frames of its envelope protein gene in zebrafish genome. Similarly, several envelope proteins of endogenous retroviruses in human and other mammalian animal genomes (such as syncytin-1 and 2 in human, syncytin-A and B in mouse) were identified and shown to be functional in induction of cell–cell fusion involved in placental development. ZFERV envelope protein (Env) gene appears to be also functional in vivo because it is expressible. After sequence alignment, we found ZFERV Env shares similar structural profiles with syncytin and other type I viral envelopes, especially in the regions of N- and C-terminal heptad repeats (NHR and CHR) which were crucial for membrane fusion. We expressed the regions of N + C protein in the ZFERV Env (residues 459–567, including predicted NHR and CHR) to characterize the fusion core structure. We found N + C protein could form a stable coiled-coil trimer that consists of three helical NHR regions forming a central trimeric core, and three helical CHR regions packing into the grooves on the surface of the central core. The structural characterization of the fusion core revealed the possible mechanism of fusion mediated by ZFERV Env. These results gave comprehensive explanation of how the ancient virus infects the zebrafish and integrates into the genome million years ago, and showed a rational clue for discovery of physiological significance (e.g., medicate cell–cell fusion). - Highlights: • ZFERV Env shares similar structural profiles with syncytin and other type I viral envelopes. • The fusion core of ZFERV Env forms stable coiled-coil trimer including three NHRs and three CHRs. • The structural mechanism of viral entry mediated by ZFERV Env is disclosed. • The results are helpful for further discovery of physiological function of ZFERV Env in zebrafish.

  12. Linkage of the Fv-2 gene to a newly reinserted ecotropic retrovirus in Fv-2 congenic mice.

    PubMed Central

    Mowat, M; Bernstein, A

    1983-01-01

    Restriction enzyme and Southern gel analyses were used to determine the number and location of endogenous ecotropic retroviruses in the germ line of several mouse strains congenic at the Fv-2 gene locus. A new endogenous ecotropic provirus was observed in the germ line of B6.S (Fv-2ss) mice, in addition to the resident provirus found in its congenic partner C57BL/6 (Fv-2rr). This new provirus was similar in structure to the C57BL provirus. The SIM strain of mice, the donors of the Fv-2s allele in B6.S mice, does not contain ecotropic proviruses, suggesting that the new provirus in the B6.S mouse strain arose by germ-line reintegration during the construction of this strain. Mendelian segregation analysis indicated that this new provirus was linked to the Fv-2 gene locus on chromosome 9. In three other Fv-2s congenic mouse strains--B10.C (47N), B6.C (H-7b), and C57BL/6J Trfa, Bgsd--no additional ecotropic endogenous viruses were detected, suggesting that the reinsertion event that occurred during the construction of B6.S is not essential for the acquisition of the Fv-2s phenotype in the C57BL genetic background. Although numerous reports of germ-line reinsertions of ecotropic virus in high-virus mouse strains have been received, the present results provide definitive evidence that similar germ-line amplifications of endogenous ecotropic virus can occur in a low-virus mouse strain. Images PMID:6620461

  13. Stimulating endogenous cardiac repair

    PubMed Central

    Finan, Amanda; Richard, Sylvain

    2015-01-01

    The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration, a combination of these approaches could ameliorate the overall repair process to incorporate the participation of multiple cellular players. PMID:26484341

  14. Postinhibitory rebound neurons and networks are disrupted in retrovirus-induced spongiform neurodegeneration

    PubMed Central

    Li, Ying; Davey, Robert A.; Lynch, William P.

    2014-01-01

    Certain retroviruses induce progressive spongiform motor neuron disease with features resembling prion diseases and amyotrophic lateral sclerosis. With the neurovirulent murine leukemia virus (MLV) FrCasE, Env protein expression within glia leads to postsynaptic vacuolation, cellular effacement, and neuronal loss in the absence of neuroinflammation. To understand the physiological changes associated with MLV-induced spongiosis, and its neuronal specificity, we employed patch-clamp recordings and voltage-sensitive dye imaging in brain slices of the mouse inferior colliculus (IC), a midbrain nucleus that undergoes extensive spongiosis. IC neurons characterized by postinhibitory rebound firing (PIR) were selectively affected in FrCasE-infected mice. Coincident with Env expression in microglia and in glia characterized by NG2 proteoglycan expression (NG2 cells), rebound neurons (RNs) lost PIR, became hyperexcitable, and were reduced in number. PIR loss and hyperexcitability were reversed by raising internal calcium buffer concentrations in RNs. PIR-initiated rhythmic circuits were disrupted, and spontaneous synchronized bursting and prolonged depolarizations were widespread. Other IC neuron cell types and circuits within the same degenerative environment were unaffected. Antagonists of NMDA and/or AMPA receptors reduced burst firing in the IC but did not affect prolonged depolarizations. Antagonists of L-type calcium channels abolished both bursts and slow depolarizations. IC infection by the nonneurovirulent isogenic virus Friend 57E (Fr57E), whose Env protein is structurally similar to FrCasE, showed no RN hyperactivity or cell loss; however, PIR latency increased. These findings suggest that spongiform neurodegeneration arises from the unique excitability of RNs, their local regulation by glia, and the disruption of this relationship by glial expression of abnormal protein. PMID:25252336

  15. Postinhibitory rebound neurons and networks are disrupted in retrovirus-induced spongiform neurodegeneration.

    PubMed

    Li, Ying; Davey, Robert A; Sivaramakrishnan, Shobhana; Lynch, William P

    2014-08-01

    Certain retroviruses induce progressive spongiform motor neuron disease with features resembling prion diseases and amyotrophic lateral sclerosis. With the neurovirulent murine leukemia virus (MLV) FrCasE, Env protein expression within glia leads to postsynaptic vacuolation, cellular effacement, and neuronal loss in the absence of neuroinflammation. To understand the physiological changes associated with MLV-induced spongiosis, and its neuronal specificity, we employed patch-clamp recordings and voltage-sensitive dye imaging in brain slices of the mouse inferior colliculus (IC), a midbrain nucleus that undergoes extensive spongiosis. IC neurons characterized by postinhibitory rebound firing (PIR) were selectively affected in FrCasE-infected mice. Coincident with Env expression in microglia and in glia characterized by NG2 proteoglycan expression (NG2 cells), rebound neurons (RNs) lost PIR, became hyperexcitable, and were reduced in number. PIR loss and hyperexcitability were reversed by raising internal calcium buffer concentrations in RNs. PIR-initiated rhythmic circuits were disrupted, and spontaneous synchronized bursting and prolonged depolarizations were widespread. Other IC neuron cell types and circuits within the same degenerative environment were unaffected. Antagonists of NMDA and/or AMPA receptors reduced burst firing in the IC but did not affect prolonged depolarizations. Antagonists of L-type calcium channels abolished both bursts and slow depolarizations. IC infection by the nonneurovirulent isogenic virus Friend 57E (Fr57E), whose Env protein is structurally similar to FrCasE, showed no RN hyperactivity or cell loss; however, PIR latency increased. These findings suggest that spongiform neurodegeneration arises from the unique excitability of RNs, their local regulation by glia, and the disruption of this relationship by glial expression of abnormal protein. PMID:25252336

  16. Recombinational junctions of variants of Moloney murine sarcoma virus: generation and divergence of a mammalian transforming gene.

    PubMed Central

    Donoghue, D J; Hunter, T

    1983-01-01

    Different variants of Moloney murine sarcoma virus (MSV) were examined by nucleotide sequencing to compare the junctions between the acquired cellular sequence, v-mos, and the adjacent virus-derived sequences. These variants included 124-MSV, m1-MSV, and HT1-MSV and also the purportedly independent isolate Gazdar MSV. These four strains have an identical 5' junction between the murine leukemia virus env gene and the v-mos gene. This junction lies within the sixth codon of the chimeric env-mos coding region that encodes the transforming gene product. In contrast, at the 3' junction between the v-mos gene and the murine leukemia virus env gene, the three variants examined here were all different. A small deletion was found in the COOH-terminal portion of the m1-MSV env-mos coding region, indicating that the COOH terminus of this transforming gene product must be different from that of 124-MSV or HT1-MSV. The data presented here are consistent with the thesis that a virus closely related to HT1-MSV was the primordial Moloney MSV, and that all other related strains evolved from it by deletion or rearrangement. The variability observed in the Moloney MSV family is discussed in terms of possible mechanisms for the initial capture of mos sequences by the parental retrovirus and also in comparison with other transforming retrovirus families, such as Abelson murine leukemia virus and Rous sarcoma virus. PMID:6300424

  17. Oncogene Activation in Myeloid Leukemias by Graffi Murine Leukemia Virus Proviral Integration

    PubMed Central

    Denicourt, Catherine; Edouard, Elsy; Rassart, Eric

    1999-01-01

    The Graffi murine leukemia virus (MuLV) is a nondefective retrovirus that induces granulocytic leukemia in BALB/c and NFS mice. To identify genes involved in Graffi MuLV-induced granulocytic leukemia, tumor cell DNAs were examined for genetic alterations at loci described as common proviral integration sites in MuLV-induced myeloid, lymphoid, and erythroid leukemias. Southern blot analysis revealed rearrangements in c-myc, Fli-1, Pim-1, and Spi-1/PU.1 genes in 20, 10, 3.3, and 3.3% of the tumors tested, respectively. These results demonstrate for the first time the involvement of those genes in granulocytic leukemia. PMID:10196342

  18. Ancestral Mutations Acquired in Refrex-1, a Restriction Factor against Feline Retroviruses, during its Cooption and Domestication

    PubMed Central

    Ito, Jumpei; Baba, Takuya; Kawasaki, Junna

    2015-01-01

    ABSTRACT Endogenous retroviruses (ERVs) are remnants of ancestral retroviral infections of germ cells. Retroviral endogenization is an adaptation process for the host genome, and ERVs are gradually attenuated or inactivated by mutation. However, some ERVs that have been “domesticated” by their hosts eventually gain physiological functions, such as placentation or viral resistance. We previously reported the discovery of Refrex-1, a soluble antiretroviral factor in domestic cats that specifically inhibits infection by feline leukemia virus subgroup D (FeLV-D), a chimeric virus of FeLV, and a feline ERV, ERV-DC. Refrex-1 is a truncated envelope protein (Env) encoded by both ERV-DC7 and ERV-DC16 proviral loci. Here, we reconstituted ancestral and functional Env from ERV-DC7 and ERV-DC16 envelope genes (env) by inducing reverse mutations. Unexpectedly, ERV-DC7 and ERV-DC16 full-length Env (ERV-DC7 fl and ERV-DC16 fl), reconstructed by removing stop codons, did not produce infectious viral particles. ERV-DC7 fl and ERV-DC16 fl were highly expressed in cells but were not cleaved into surface subunits (SU) and transmembrane subunits, nor were they incorporated into virions. G407R/N427I-A429T and Y431D substitutions within the SU C-terminal domain of ERV-DC7 fl and ERV-DC16 fl, respectively, caused these dysfunctions. The residues glycine 407 and tyrosine 431 are relatively conserved among infectious gammaretroviruses, and their substitution causes the same dysfunctions as the tested retroviruses. Our results reveal that specific mutations within the SU C-terminal domain suppressed Env cleavage and incorporation into virions and indicate that these mutations contributed to the domestication of Refrex-1 through multistep events that occurred in the postintegration period. IMPORTANCE Domestic cats are colonized with various exogenous retroviruses (exRVs), such as feline leukemia virus (FeLV), and their genomes contain numerous ERVs, some of which are replication

  19. Endogenous Erythropoietin Protects Neuroretinal Function in Ischemic Retinopathy

    PubMed Central

    Mowat, Freya M.; Gonzalez, Francisco; Luhmann, Ulrich F.O.; Lange, Clemens A.; Duran, Yanai; Smith, Alexander J.; Maxwell, Patrick H.; Ali, Robin R.; Bainbridge, James W.B.

    2012-01-01

    Because retinal ischemia is a common cause of vision loss, we sought to determine the effects of ischemia on neuroretinal function and survival in murine oxygen-induced retinopathy (OIR) and to define the role of endogenous erythropoietin (EPO) in this model. OIR is a reproducible model of ischemia-induced retinal neovascularization; it is used commonly to develop antiangiogenic strategies. We investigated the effects of ischemia in murine OIR on retinal function and neurodegeneration by electroretinography and detailed morphology. OIR was associated with significant neuroretinal dysfunction, with reduced photopic and scotopic ERG responses and reduced b-wave/a-wave ratios consistent with specific inner-retinal dysfunction. OIR resulted in significantly increased apoptosis and atrophy of the inner retina in areas of ischemia. EPO deficiency in heterozygous Epo-Tag transgenic mice was associated with more profound retinal dysfunction after OIR, indicated by a significantly greater suppression of ERG amplitudes, but had no measurable effect on the extent of retinal ischemia, preretinal neovascularization, or neuroretinal degeneration in OIR. Systemic administration of recombinant EPO protected EPO-deficient mice against this additional suppression, but EPO supplementation in wild-type animals with OIR did not rescue neuroretinal dysfunction or degeneration. Murine OIR offers a valuable model of ischemic neuroretinal dysfunction and degeneration in which to investigate adaptive tissue responses and evaluate novel therapeutic approaches. Endogenous EPO can protect neuroretinal function in ischemic retinopathy. PMID:22342523

  20. Suppression subtractive hybridization method for the identification of a new strain of murine hepatitis virus from xenografted SCID mice.

    PubMed

    Islam, Mohammed M; Toohey, Brendan; Purcell, Damian F J; Kannourakis, George

    2015-12-01

    During attempts to clone retroviral determinants associated with a mouse model of Langerhans cell histiocytosis (LCH), suppression subtractive hybridization (SSH) was used to identify unique viruses in the liver of severe combined immunodeficiency (SCID) mice transplanted with LCH tissues. A partial genomic sequence of a murine coronavirus was identified, and the whole genome (31428 bp) of the coronavirus was subsequently sequenced using PCR cloning techniques. Nucleotide sequence comparisons revealed that the genome sequence of the new virus was 91-93% identical to those of known murine hepatitis viruses (MHVs). The predicted open reading frame from the nucleotide sequence encoded all known proteins of MHVs. Analysis at the protein level showed that the virus was closely related to the highly virulent MHV-JHM strain. The virus strain was named MHV-MI. No type D retroviruses were found. Degenerate PCR targeting of type D retrovirus and 5'-RACE targeting of other types of retroviruses confirmed the absence of any retroviral association with the LCH xenografted SCID mice. PMID:26347284

  1. New class of leukemogenic ecotropic recombinant murine leukemia virus isolated from radiation-induced thymomas of C57BL/6 mice

    SciTech Connect

    Rassart, E.; Sankar-Mistry, P.; Lemay, G.; DesGroseillers, L.; Jalicoeur, P.

    1983-02-01

    We previously reported the establishment of several lymphoid cell lines from X-ray-induced thymomas of C57BL/Ka mice, and all, except one, produce retroviruses. Biological characterization of five of these new primary radiation leukemia viruses (RadLVs) indicated that they had a B-tropic, fibrotropic, and ecotropic host range and were leukemogenic when reinjected into C57BL/Ka newborn mice. The leukemogenic potential of one isolate (G/sub 6/T/sub 2/) was further assessed and shown to be retained after prolonged passaging on fibroblasts in vitro. Restriction endonuclease analysis of the DNA of four of our new RadLV isolates (G/sub 6/T/sub 2/, Ti-7, Ti-8, and Ti-9) revealed that G/sub 6/T/sub 2/ and Ti-7 murine leukemia virus (MuLV) genomes had identical restriction maps, whereas Ti-8 and Ti-9 genomes were different from each other and from the G/sub 6/T/sub 2/ and Ti-7 genomes. The physical maps of these genomes were similar to that of known ecotropic MuLV genomes (including the C57BL/Ka endogenous ecotropic MuLV) within their long terminal repeats, env, the right portion of pol, and the left portion of gag. However, a region covering the end of gag and the beginning of pol was different and showed several similarities with xenotropic MuLV genomes of BALB/c, AKR, and C58 mice previously mapped. Our results suggest that these primary RadLV genomes are recombinants between the parental ecotropic MuLV genome and a nonecotropic (xenotropic) sequence. To further study the leukemic potential of these RadLVs, the genome of one of them (G/sub 6/T/sub 2/) was cloned in Charon 21A as an infectious molecule.

  2. Interplay of TRIM28 and DNA methylation in controlling human endogenous retroelements.

    PubMed

    Turelli, Priscilla; Castro-Diaz, Nathaly; Marzetta, Flavia; Kapopoulou, Adamandia; Raclot, Charlène; Duc, Julien; Tieng, Vannary; Quenneville, Simon; Trono, Didier

    2014-08-01

    Reverse transcription-derived sequences account for at least half of the human genome. Although these retroelements are formidable motors of evolution, they can occasionally cause disease, and accordingly are inactivated during early embryogenesis through epigenetic mechanisms. In the mouse, at least for endogenous retroviruses, important mediators of this process are the tetrapod-specific KRAB-containing zinc finger proteins (KRAB-ZFPs) and their cofactor TRIM28. The present study demonstrates that KRAB/TRIM28-mediated regulation is responsible for controlling a very broad range of human-specific endogenous retroelements (EREs) in human embryonic stem (ES) cells and that it exerts, as a consequence, a marked effect on the transcriptional dynamics of these cells. It further reveals reciprocal dependence between TRIM28 recruitment at specific families of EREs and DNA methylation. It finally points to the importance of persistent TRIM28-mediated control of ERE transcriptional impact beyond their presumed inactivation by DNA methylation. PMID:24879559

  3. Pseudotypes of vesicular stomatitis virus with the envelope properties of mammalian and primate retroviruses.

    PubMed

    Schnitzer, T J; Weiss, R A; Zavada, J

    1977-09-01

    By employing improved techniques it has been possible to produce and characterize a representative spectrum of mammalian and primate retrovirus pseudotypes of vesicular stomatitis virus (VSV). Selection of appropriate cell lines for both the production and subsequent detection of the VSV pseudotypes has been the most important factor in permitting their demonstration. The host range for penetration of these retrovirus pseudotypes of VSV has been defined and found to differ from that reported for the replication of the corresponding retroviruses. Additionally, retroviruses having an identical host range for replication were distinguishable by differences in their host range for penetration, implying that restriction of replication may be occurring by different mechanisms. Studies of the plaque-forming efficiency of retrovirus pseudotypes of VSV in cell lines nonpermissive for replication of the corresponding retroviruses permitted a distinction to be made between the restriction of replication occurring as a consequence of postpenetration events and that occurring as a consequence of a block of penetration itself. The demonstration of primate retrovirus pseudotypes of VSV permits the use of VSV as a probe for the detection of this group of viruses. PMID:197255

  4. Endogenous non-retroviral RNA virus elements evidence a novel type of antiviral immunity.

    PubMed

    Honda, Tomoyuki; Tomonaga, Keizo

    2016-01-01

    Vertebrate genomes contain many virus-related sequences derived from both retroviruses and non-retroviral RNA and DNA viruses. Such non-retroviral RNA sequences are possibly produced by reverse-transcription and integration of viral mRNAs of ancient RNA viruses using retrotransposon machineries. We refer to this process as transcript reversion. During an ancient bornavirus infection, transcript reversion may have left bornavirus-related sequences, known as endogenous bornavirus-like nucleoproteins (EBLNs), in the genome. We have recently demonstrated that all Homo sapiens EBLNs are expressed in at least one tissue. Because species with EBLNs appear relatively protected against infection by a current bornavirus, Borna disease virus, it is speculated that EBLNs play some roles in antiviral immunity, as seen with some endogenous retroviruses. EBLNs can function as dominant negative forms of viral proteins, small RNAs targeting viral sequences, or DNA or RNA elements modulating the gene expression. Growing evidence reveals that various RNA viruses are reverse-transcribed and integrated into the genome of infected cells, suggesting transcript reversion generally occurs during ongoing infection. Considering this, transcript reversion-mediated interference with related viruses may be a novel type of antiviral immunity in vertebrates. Understanding the biological significance of transcript reversion will provide novel insights into host defenses against viral infections. PMID:27510928

  5. Endogenous retroviral long terminal repeats within the HLA-DQ locus.

    PubMed Central

    Kambhu, S; Falldorf, P; Lee, J S

    1990-01-01

    Two endogenous retroviral long terminal repeats (LTRs) were found in the human major histocompatibility complex locus HLA-DQ. The solo LTRs, unlinked to retrovirus structural genes, are located approximately 5 kilobases apart from each other and in the same transcriptional orientation, which is opposite to that for the HLA-DQB1 gene. These elements exhibit greater than 90% homology to the LTRs of the human endogenous retrovirus HERV-K10. The conservation of putative regulatory elements found within the LTRs and their position relative to the HLA-DQB1 gene suggest that these elements may confer distinct regulatory properties on genes in the HLA-DQ region. Polymorphic variation between different HLA haplotypes for the presence of the LTRs at this location and of the molecular architecture within this subregion is supported by polymerase chain reaction and Southern blot analysis. Comparisons of chromosomes with and without the LTRs in this region will provide a unique opportunity in the human genome to analyze transposition or integration of retroviral sequences. Images PMID:2114643

  6. Endogenous non-retroviral RNA virus elements evidence a novel type of antiviral immunity

    PubMed Central

    Honda, Tomoyuki; Tomonaga, Keizo

    2016-01-01

    ABSTRACT Vertebrate genomes contain many virus-related sequences derived from both retroviruses and non-retroviral RNA and DNA viruses. Such non-retroviral RNA sequences are possibly produced by reverse-transcription and integration of viral mRNAs of ancient RNA viruses using retrotransposon machineries. We refer to this process as transcript reversion. During an ancient bornavirus infection, transcript reversion may have left bornavirus-related sequences, known as endogenous bornavirus-like nucleoproteins (EBLNs), in the genome. We have recently demonstrated that all Homo sapiens EBLNs are expressed in at least one tissue. Because species with EBLNs appear relatively protected against infection by a current bornavirus, Borna disease virus, it is speculated that EBLNs play some roles in antiviral immunity, as seen with some endogenous retroviruses. EBLNs can function as dominant negative forms of viral proteins, small RNAs targeting viral sequences, or DNA or RNA elements modulating the gene expression. Growing evidence reveals that various RNA viruses are reverse-transcribed and integrated into the genome of infected cells, suggesting transcript reversion generally occurs during ongoing infection. Considering this, transcript reversion-mediated interference with related viruses may be a novel type of antiviral immunity in vertebrates. Understanding the biological significance of transcript reversion will provide novel insights into host defenses against viral infections. PMID:27510928

  7. Genetic Engineering of T cells to Target HERV-K, an Ancient Retrovirus on Melanoma

    PubMed Central

    Krishnamurthy, Janani; Rabinovich, Brian A.; Mi, Tiejuan; Switzer, Kirsten C.; Olivares, Simon; Maiti, Sourindra N.; Plummer, Joshua B.; Singh, Harjeet; Kumaresan, Pappanaicken R.; Huls, Helen M.; Wang-Johanning, Feng; Cooper, Laurence J.N.

    2015-01-01

    Purpose The human endogenous retrovirus (HERV-K) envelope (env) protein is a tumor- associated antigen expressed on melanoma, but not normal cells. This study was designed to engineer a chimeric antigen receptor (CAR) on T cell surface, such that they target tumors in advanced stages of melanoma. Experimental Design Expression of HERV-K protein was analyzed in 220 melanoma samples (with various stages of disease) and 139 normal organ donor tissues using immuno-histochemical (IHC) analysis. HERV-K env-specific CAR derived from mouse monoclonal antibody was introduced into T cells using the transposon-based Sleeping Beauty (SB) system. HERV-K env-specific CAR+ T cells were expanded ex vivo on activating and propagating cells (AaPC), and characterized for CAR expression and specificity. This includes evaluating the HERV-K-specific CAR+ T cells for their ability to kill A375-SM metastasized tumors in a mouse xenograft model. Results We detected HERV-K env protein on melanoma, but not in normal tissues. After electroporation of T cells and selection on HERV-K+ AaPC, over 95% of genetically-modified T cells expressed the CAR with an effector memory phenotype and lysed HERV-K env+ tumor targets in an antigen specific manner. Even though there is apparent shedding of this TAA from tumor cells which can be recognized by HERV-K env-specific CAR+ T cells, we observed a significant anti-tumor effect. Conclusion Adoptive cellular immunotherapy with HERV-K env-specific CAR+ T cells represents a clinically-appealing treatment strategy for advanced-stage melanoma and provides an approach for targeting this TAA on other solid tumors. PMID:25829402

  8. On the general theory of the origins of retroviruses

    PubMed Central

    2010-01-01

    Background The order retroviridae comprises viruses based on ribonucleic acids (RNA). Some, such as HIV and HTLV, are human pathogens. Newly emerged human retroviruses have zoonotic origins. As far as has been established, both repeated infections (themselves possibly responsible for the evolution of viral mutations (Vm) and host adaptability (Ha)); along with interplay between inhibitors and promoters of cell tropism, are needed to effect retroviral cross-species transmissions. However, the exact modus operadi of intertwine between these factors at molecular level remains to be established. Knowledge of such intertwine could lead to a better understanding of retrovirology and possibly other infectious processes. This study was conducted to derive the mathematical equation of a general theory of the origins of retroviruses. Methods and results On the basis of an arbitrarily non-Euclidian geometrical "thought experiment" involving the cross-species transmission of simian foamy virus (sfv) from a non-primate species Xy to Homo sapiens (Hs), initially excluding all social factors, the following was derived. At the port of exit from Xy (where the species barrier, SB, is defined by the Index of Origin, IO), sfv shedding is (1) enhanced by two transmitting tensors (Tt), (i) virus-specific immunity (VSI) and (ii) evolutionary defenses such as APOBEC, RNA interference pathways, and (when present) expedited therapeutics (denoted e2D); and (2) opposed by the five accepting scalars (At): (a) genomic integration hot spots, gIHS, (b) nuclear envelope transit (NMt) vectors, (c) virus-specific cellular biochemistry, VSCB, (d) virus-specific cellular receptor repertoire, VSCR, and (e) pH-mediated cell membrane transit, (↓pH CMat). Assuming As and Tt to be independent variables, IO = Tt/As. The same forces acting in an opposing manner determine SB at the port of sfv entry (defined here by the Index of Entry, IE = As/Tt). Overall, If sfv encounters no unforeseen effects on transit

  9. Cloning of murine ferrochelatase.

    PubMed Central

    Brenner, D A; Frasier, F

    1991-01-01

    Ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1) catalyzes the last step in the heme biosynthetic pathway, the chelation of ferrous iron and protoporphyrin to form heme. The activity of ferrochelatase is deficient in the inherited disease protoporphyria. In this study, murine ferrochelatase cDNAs were obtained by screening cDNA libraries with an oligonucleotide probe. The derived amino acid sequence of murine ferrochelatase has 47% identity with the recently cloned Saccharomyces cerevisiae ferrochelatase, but it is not significantly similar to other published sequences. Results of Southern blotting are consistent with a single murine ferrochelatase gene, while Northern blotting demonstrates two ferrochelatase transcripts in all tissues examined. The ferrochelatase protein and mRNAs have different relative concentrations in different tissues. The cloning of murine ferrochelatase cDNAs provides the basis for future studies on ferrochelatase gene expression and on the identification of the molecular defect in protoporphyria. Images PMID:1704134

  10. Isothiocyanates Ameliorate the Symptom of Heart Dysfunction and Mortality in a Murine AIDS Model by Inhibiting Apoptosis in the Left Ventricle

    PubMed Central

    Ho, Jin-Nyoung; Yoon, Ho-Geun; Park, Chang-Soo; Kim, Sunoh; Jun, Woojin; Choue, Ryowon

    2012-01-01

    Abstract Cardiac involvement has been reported in as many as 45–55% of patients with human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS), and significant cardiac morbidity is reported in 6–7% of HIV patients. We investigated the inhibitory effects of isothiocyanates (ITCs) on heart dysfunction and mortality by regulating apoptosis in the left ventricle of the heart in a murine AIDS model. Mice were divided into six groups: an uninfected group, an untreated LP-BM5 retrovirus-infected group, and four LP-BM5 retrovirus-infected groups treated with one of four ITCs (sulforaphane [SUL], indolo[3,2-b]carbazole, benzyl isothiocyanate [BITC], or phenethyl isothiocyanate [PEITC]). After 16 weeks, the median survival time of the LP-BM5 retrovirus-infected mice was 87 days, whereas that of the uninfected control group and all ITC treatment groups was over 112 days. SUL, PEITC, and BITC significantly inhibited apoptosis in the left ventricle by increasing the Bcl-2/Bax ratio compared with LP-BM5-infected mice. In addition, SUL and PEITC suppressed inducible nitric oxide synthase (iNOS) expression at both the mRNA and protein levels in the left ventricle of heart tissue infected with the LP-BM5 retrovirus by inactivating cytoplasmic nuclear factor κB (NF-κB). In conclusion, LP-BM5 retrovirus infection was related to survival of murine AIDS mice, and NF-κB-mediated iNOS expression may be an important mediator of left ventricle dysfunction of the heart. Furthermore, certain ITCs may have the potential to improve AIDS-related heart dysfunction due to their inhibition of apoptosis by decreasing iNOS and Bax expression through suppression of NF-κB. PMID:22925072

  11. Targeting of a Nuclease to Murine Leukemia Virus Capsids Inhibits Viral Multiplication

    NASA Astrophysics Data System (ADS)

    Natsoulis, Georges; Seshaiah, Partha; Federspiel, Mark J.; Rein, Alan; Hughes, Stephen H.; Boeke, Jef D.

    1995-01-01

    Capsid-targeted viral inactivation is an antiviral strategy in which toxic fusion proteins are targeted to virions, where they inhibit viral multiplication by destroying viral components. These fusion proteins consist of a virion structural protein moiety and an enzymatic moiety such as a nuclease. Such fusion proteins can severely inhibit transposition of yeast retrotransposon Ty1, an element whose transposition mechanistically resembles retroviral multiplication. We demonstrate that expression of a murine retrovirus capsid-staphylococcal nuclease fusion protein inhibits multiplication of the corresponding murine leukemia virus by 30- to 100-fold. Staphylococcal nuclease is apparently inactive intracellularly and hence nontoxic to the host cell, but it is active extracellularly because of its requirement for high concentrations of Ca2+ ions. Virions assembled in and shed from cells expressing the fusion protein contain very small amounts of intact viral RNA, as would be predicted for nuclease-mediated inhibition of viral multiplication.

  12. Endogenous pulmonary antibiotics.

    PubMed

    Gibbons, M A; Bowdish, D M; Davidson, D J; Sallenave, J M; Simpson, A J

    2006-05-01

    The human lung produces a variety of peptides and proteins which have intrinsic antimicrobial activity. In general these molecules have broad spectra of antimicrobial activity, kill micro-organisms rapidly, and evade resistance generated by pathogens. In recent years it has become increasingly apparent that the antimicrobial peptides (AMPs) simultaneously possess immunomodulatory functions, suggesting complex roles for these molecules in regulating the clearance of, and immune response to, invading pathogens. These collective properties have stimulated considerable interest in the potential clinical application of endogenous AMPs. This article outlines the biology of AMPs, their pattern of expression in the lung, and their functions, with reference to both antimicrobial and immunomodulatory activity. We then consider the biological importance of AMPs, before concentrating on the potential to use AMPs to therapeutic effect. The principles discussed in the article apply to innate immune defence throughout the body, but particular emphasis is placed on AMPs in the lung and the potential application to pulmonary infection. PMID:16722137

  13. Angiostatin and endostatin: endogenous inhibitors of tumor growth.

    PubMed

    Sim, B K; MacDonald, N J; Gubish, E R

    2000-01-01

    Considerable progress has been made in the understanding of the molecular structure and mechanistic aspects of Angiostatin and Endostatin, endogenous angiogenesis inhibitors that have been shown to regress tumors in murine models. The growing body of literature surrounding these molecules and on the efficacy of these proteins is in part due to the ability to generate these proteins in recombinant systems as well characterized molecules. Recombinant human Angiostatin and Endostatin are in Phase I trials, following the manufacture of clinical grade material at large scale. This review highlights the recent advances made on understanding the structure and function of Angiostatin and Endostatin. PMID:11191058

  14. The ability of multimerized cyclophilin A to restrict retrovirus infection

    SciTech Connect

    Javanbakht, Hassan; Diaz-Griffero, Felipe; Yuan Wen; Yeung, Darwin F.; Li Xing; Song Byeongwoon; Sodroski, Joseph

    2007-10-10

    In owl monkeys, the typical retroviral restriction factor of primates, TRIM5{alpha}, is replaced by TRIMCyp. TRIMCyp consists of the TRIM5 RING, B-box 2 and coiled-coil domains, as well as the intervening linker regions, fused with cyclophilin A. TRIMCyp restricts infection of retroviruses, such as human immunodeficiency virus (HIV-1) and feline immunodeficiency virus (FIV), with capsids that can bind cyclophilin A. The TRIM5 coiled coil promotes the trimerization of TRIMCyp. Here we show that cyclophilin A that is oligomeric as a result of fusion with a heterologous multimer exhibits substantial antiretroviral activity. The addition of the TRIM5 RING, B-box 2 and Linker 2 to oligomeric cyclophilin A generated a protein with antiretroviral activity approaching that of wild-type TRIMCyp. Multimerization increased the binding of cyclophilin A to the HIV-1 capsid, promoting accelerated uncoating of the capsid and restriction of infection.

  15. A computational model for predicting fusion peptide of retroviruses.

    PubMed

    Wu, Sijia; Han, Jiuqiang; Liu, Ruiling; Liu, Jun; Lv, Hongqiang

    2016-04-01

    As a pivotal domain within envelope protein, fusion peptide (FP) plays a crucial role in pathogenicity and therapeutic intervention. Taken into account the limited FP annotations in NCBI database and absence of FP prediction software, it is urgent and desirable to develop a bioinformatics tool to predict new putative FPs (np-FPs) in retroviruses. In this work, a sequence-based FP model was proposed by combining Hidden Markov Method with similarity comparison. The classification accuracies are 91.97% and 92.31% corresponding to 10-fold and leave-one-out cross-validation. After scanning sequences without FP annotations, this model discovered 53,946 np-FPs. The statistical results on FPs or np-FPs reveal that FP is a conserved and hydrophobic domain. The FP software programmed for windows environment is available at https://sourceforge.net/projects/fptool/files/?source=navbar. PMID:26963379

  16. A Simple Model for Immature Retrovirus Capsid Assembly

    NASA Astrophysics Data System (ADS)

    Paquay, Stefan; van der Schoot, Paul; Dragnea, Bogdan

    In this talk I will present simulations of a simple model for capsomeres in immature virus capsids, consisting of only point particles with a tunable range of attraction constrained to a spherical surface. We find that, at sufficiently low density, a short interaction range is sufficient for the suppression of five-fold defects in the packing and causes instead larger tears and scars in the capsid. These findings agree both qualitatively and quantitatively with experiments on immature retrovirus capsids, implying that the structure of the retroviral protein lattice can, for a large part, be explained simply by the effective interaction between the capsomeres. We thank the HFSP for funding under Grant RGP0017/2012.

  17. The ability of multimerized cyclophilin A to restrict retrovirus infection.

    PubMed

    Javanbakht, Hassan; Diaz-Griffero, Felipe; Yuan, Wen; Yeung, Darwin F; Li, Xing; Song, Byeongwoon; Sodroski, Joseph

    2007-10-10

    In owl monkeys, the typical retroviral restriction factor of primates, TRIM5alpha, is replaced by TRIMCyp. TRIMCyp consists of the TRIM5 RING, B-box 2 and coiled-coil domains, as well as the intervening linker regions, fused with cyclophilin A. TRIMCyp restricts infection of retroviruses, such as human immunodeficiency virus (HIV-1) and feline immunodeficiency virus (FIV), with capsids that can bind cyclophilin A. The TRIM5 coiled coil promotes the trimerization of TRIMCyp. Here we show that cyclophilin A that is oligomeric as a result of fusion with a heterologous multimer exhibits substantial antiretroviral activity. The addition of the TRIM5 RING, B-box 2 and Linker 2 to oligomeric cyclophilin A generated a protein with antiretroviral activity approaching that of wild-type TRIMCyp. Multimerization increased the binding of cyclophilin A to the HIV-1 capsid, promoting accelerated uncoating of the capsid and restriction of infection. PMID:17574642

  18. Tightly bound zinc in human immunodeficiency virus type 1, human T-cell leukemia virus type I, and other retroviruses.

    PubMed Central

    Bess, J W; Powell, P J; Issaq, H J; Schumack, L J; Grimes, M K; Henderson, L E; Arthur, L O

    1992-01-01

    Human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) were purified by sucrose density gradient centrifugation in the presence of 1 mM EDTA. Pelleted gradient fractions were analyzed for total protein, total Gag capsid protein, and total zinc. Zinc was found to copurify and concentrate with the virus particles. Through successive cycles of resuspending in buffer containing EDTA and repelleting, the zinc content remained constant at about 1.7 mol of zinc per mol of Gag protein. Proteins from purified virus (HIV-1 and HTLV-I) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to polyvinylidene fluoride paper, and probed with 65ZnCl2. Viral nucleocapsid (NC) proteins (HIV-1 p7NC and HTLV-I p15NC) bound 65Zn2+. Other retroviruses, including simian immunodeficiency virus, equine infectious anemia virus, bovine leukemia virus, Moloney murine leukemia virus, mouse mammary tumor virus, and Mason-Pfizer monkey virus, were found to contain amounts of zinc per milligram of total protein similar to those found in HIV-1 and HTLV-I. Collectively, these data support the hypothesis that retroviral NC proteins function as zinc finger proteins in mature viruses. Images PMID:1731111

  19. Inhibition of catecholamine degradation ameliorates while chemical sympathectomy aggravates the severity of acute Friend retrovirus infection in mice.

    PubMed

    Bloemker, Dominique; Mollerus, Sina; Gibbert, Kathrin; Dittmer, Ulf; del Rey, Adriana; Schedlowski, Manfred; Engler, Harald

    2016-05-01

    Several lines of evidence indicate that the sympathetic nervous system (SNS) might be involved in the pathogenesis and progression of retroviral infections. However, experimental data are scarce and findings inconsistent. Here, we investigated the role of the SNS during acute infection with Friend virus (FV), a pathogenic murine retrovirus that causes polyclonal proliferation of erythroid precursor cells and splenomegaly in adult mice. Experimental animals were infected with FV complex, and viral load, spleen weight, and splenic noradrenaline (NA) concentration was analyzed until 25 days post infection. Results show that FV infection caused a massive but transient depletion in splenic NA during the acute phase of the disease. At the peak of the virus-induced splenomegaly, splenic NA concentration was reduced by about 90% compared to naïve uninfected mice. Concurrently, expression of the catecholamine degrading enzymes monoamine oxidase A (MAO-A) and catechol-O-methyltransferase (COMT) was significantly upregulated in immune cells of the spleen. Pharmacological inhibition of MAO-A and COMT by the selective inhibitors clorgyline and 3,5-dinitrocatechol, respectively, efficiently blocked NA degradation and significantly reduced viral load and virus-induced splenomegaly. In contrast, chemical sympathectomy prior to FV inoculation aggravated the acute infection and extended the duration of the disease. Together these findings demonstrate that catecholamine availability at the site of viral replication is an important factor affecting the course of retroviral infections. PMID:26880342

  20. Identification of Hyal2 as the cell-surface receptor for jaagsiekte sheep retrovirus and ovine nasal adenocarcinoma virus.

    PubMed

    Miller, A D

    2003-01-01

    Jaagsiekte sheep retrovirus (JSRV) and ovine nasal adenocarcinoma virus (ONAV) replicate in the airway and cause epithelial cell tumors through the activity of their envelope (Env) proteins. Identification of the receptor(s) that mediate cell entry by these viruses is crucial to understanding the oncogenic activity of Env and for the development of gene therapy vectors based on these viruses that are capable of targeting airway cells. To identify the viral receptor(s) and to further study the biology of JSRV and ONAV, we developed retroviral vectors containing Moloney murine leukemia virus components and the Env proteins of JSRV or ONAV. We used a new technique involving positional cloning by phenotypic mapping in radiation hybrid cells to identify and clone the human receptor for JSRV, Hyal2, which also serves as the receptor for ONAV. Hyal2 is a glycosylphosphatidylinositol-anchored cell-surface protein that has low hyaluronidase activity and is a member of a large family that includes sperm hyaluronidase (Spam) and serum hyaluronidase (Hyal1). Hyal2 is located in a region of human chromosome 3p21.3 that is often deleted in lung cancer, suggesting that it may be a tumor suppressor. However, its role in JSRV or ONAV tumorigenesis, if any, is still unclear. JSRV vectors are capable of transducing various human cells, and are being further evaluated for gene therapy purposes. PMID:12596899

  1. Receptor choice determinants in the envelope glycoproteins of amphotropic, xenotropic, and polytropic murine leukemia viruses.

    PubMed Central

    Battini, J L; Heard, J M; Danos, O

    1992-01-01

    The envelope glycoproteins (SU) of mammalian type C retroviruses possess an amino-terminal domain of about 200 residues, which is involved in binding a cell surface receptor. In this domain, highly conserved amino acid sequences are interrupted by two segments of variable length and sequence, VRA and VRB. We have studied the role of these variable regions in receptor recognition and binding by constructing chimeric molecules in which portions of the amino-terminal domains from amphotropic (4070A), xenotropic (NZB), and polytropic (MCF 247) murine leukemia virus SU proteins were permuted. These chimeras, which exchanged either one or two variable regions, were expressed at the surface of replication-defective viral particles by a pseudotyping assay. Wild-type or recombinant env genes were transfected into a cell line producing Moloney murine leukemia virus particles devoid of envelope glycoproteins in which a retrovirus vector genome carrying an Escherichia coli lacZ gene was packaged. The host range and sensitivity to interference of pseudotyped virions were assayed, and we observed which permutations resulted in receptor switch or loss of function. Our results indicate that the determinants of receptor choice are found within the just 120 amino acids of SU proteins. Downstream sequences contribute to the stabilization of the receptor-specific structure. PMID:1310758

  2. Endogenous strategy in exploration.

    PubMed

    Solman, Grayden J F; Kingstone, Alan

    2015-12-01

    We examined the characteristics of endogenous exploratory behaviors in a generalized search task in which guidance signals (e.g., landmarks, semantics, visual saliency, layout) were limited or precluded. Individuals looked for the highest valued cell in an array and were scored on the quality of the best value they could find. Exploration was guided only by the cells that had been previously examined, and the value of this guidance was manipulated by adjusting spatial autocorrelation to produce relatively smooth and rough landscapes-that is, arrays in which nearby cells had unrelated values (low correlation = rough) or similar values (high correlation = smooth). For search in increasingly rough as compared with smooth arrays, we found reduced performance despite increased sampling and increased time spent searching after revelation of a searcher's best cell. Spatially, sampling strategies tended toward more excursive, branching, and space-filling patterns as correlation decreased. Using a novel generalized-recurrence analysis, we report that these patterns reflect an increase in systematic search paths, characterized by regularized sweeps with localized infilling. These tendencies were likewise enhanced for high-performance as compared with low-performance participants. The results suggest a trade-off between guidance (in smooth arrays) and systematicity (in rough arrays), and they provide insight into the particular strategic approaches adopted by searchers when exogenous guiding information is minimized. PMID:26214501

  3. [Endogenous bacterial endophthalmitis].

    PubMed

    Cornut, P-L; Chiquet, C

    2011-01-01

    Endogenous bacterial endophthalmitis, also called metastatic bacterial endophthalmitis, remains a diagnostic and therapeutic challenge. It is a rare and potentially sight-threatening ocular infection that occurs when bacteria reach the eye via the bloodstream, cross the blood-ocular barrier, and multiply within the eye. It usually affects immunocompromised patients and those suffering from diabetes mellitus, malignancy, or cardiac disease, but has also been reported after invasive procedures or in previously healthy people. In most cases, the ocular symptoms occur after the diagnosis of septicemia or systemic infection. Ocular symptoms include decreased vision, redness, discharge, pain, and floaters. The ocular inflammatory signs may be anterior and/or posterior. Bilateral involvement occurs in nearly 25% of cases. A wide range of microorganisms are involved, with differences in their frequency according to geography as well as the patient's age and past medical history, because of variations in the predisposing conditions and the source of the sepsis. The majority of patients are initially misdiagnosed, and ophthalmologists should be aware of this because prompt local and general management is required to save the eye and/or the patient's life. PMID:21145128

  4. Epigenetic upregulation of endogenous VEGF-A reduces myocardial infarct size in mice.

    PubMed

    Turunen, Mikko P; Husso, Tiia; Musthafa, Haja; Laidinen, Svetlana; Dragneva, Galina; Laham-Karam, Nihay; Honkanen, Sanna; Paakinaho, Anne; Laakkonen, Johanna P; Gao, Erhe; Vihinen-Ranta, Maija; Liimatainen, Timo; Ylä-Herttuala, Seppo

    2014-01-01

    "Epigenetherapy" alters epigenetic status of the targeted chromatin and modifies expression of the endogenous therapeutic gene. In this study we used lentiviral in vivo delivery of small hairpin RNA (shRNA) into hearts in a murine infarction model. shRNA complementary to the promoter of vascular endothelial growth factor (VEGF-A) was able to upregulate endogenous VEGF-A expression. Histological and multiphoton microscope analysis confirmed the therapeutic effect in the transduced hearts. Magnetic resonance imaging (MRI) showed in vivo that the infarct size was significantly reduced in the treatment group 14 days after the epigenetherapy. Importantly, we show that promoter-targeted shRNA upregulates all isoforms of endogenous VEGF-A and that an intact hairpin structure is required for the shRNA activity. In conclusion, regulation of gene expression at the promoter level is a promising new treatment strategy for myocardial infarction and also potentially useful for the upregulation of other endogenous genes. PMID:24587164

  5. Human and murine erythropoiesis

    PubMed Central

    An, Xiuli; Schulz, Vincent P.; Mohandas, Narla; Gallagher, Patrick G.

    2015-01-01

    Purpose of review Research into the fundamental mechanisms of erythropoiesis has provided critical insights into inherited and acquired disorders of the erythrocyte. Studies of human erythropoiesis have primarily utilized in-vitro systems, whereas murine models have provided insights from in-vivo studies. This report reviews recent insights into human and murine erythropoiesis gained from transcriptome-based analyses. Recent findings The availability of high-throughput genomic methodologies has allowed attainment of detailed gene expression data from cells at varying developmental and differentiation stages of erythropoiesis. Transcriptome analyses of human and murine reveal both stage and species-specific similarities and differences across terminal erythroid differentiation. Erythroid-specific long noncoding RNAs exhibit poor sequence conservation between human and mouse. Genome-wide analyses of alternative splicing reveal that complex, dynamic, stage-specific programs of alternative splicing program are utilized during terminal erythroid differentiation. Transcriptome data provide a significant resource for understanding mechanisms of normal and perturbed erythropoiesis. Understanding these processes will provide innovative strategies to detect, diagnose, prevent, and treat hematologic disease. Summary Understanding the shared and different mechanisms controlling human and murine erythropoiesis will allow investigators to leverage the best model system to provide insights in normal and perturbed erythropoiesis. PMID:25719574

  6. Interferon but not MxB inhibits foamy retroviruses.

    PubMed

    Bähr, Ariane; Singer, Anna; Hain, Anika; Vasudevan, Ananda Ayyappan Jaguva; Schilling, Mirjam; Reh, Juliane; Riess, Maximilian; Panitz, Sylvia; Serrano, Vanessa; Schweizer, Matthias; König, Renate; Chanda, Sumit; Häussinger, Dieter; Kochs, Georg; Lindemann, Dirk; Münk, Carsten

    2016-01-15

    Foamy viruses (FV) are retroviruses that are widely distributed in primate and non-primate animal species. We tested here FV with capsids of simian and non-simian origin for sensitivity to interferon-β (IFN-β). Our data show significant inhibition of FV by IFN-β early in infection of human HOS and THP-1 but not of HEK293T cells. The post-entry restriction of FV was not mediated by the interferon-induced MxB protein that was recently identified as a capsid-interacting restriction factor targeting Human immunodeficiency virus (HIV) before integration. Neither the ectopic expression of MxA or MxB in HEK293T cells nor the lack of MxB expression in CRISPR/CAS MxB THP-1 knockout cells impacted the infection of the tested FV. IFN-β treated THP-1 and THP-1 KO MxB cells showed the same extend of restriction to FV. Together, the data demonstrate that IFN-β inhibits FV early in infection and that MxB is not a restriction factor of FV. PMID:26609934

  7. Viral causes of feline lymphoma: retroviruses and beyond.

    PubMed

    Beatty, Julia

    2014-08-01

    The most widely recognised cause of feline lymphoma is the gammaretrovirus feline leukaemia virus (FeLV). Research into the mechanisms of cellular transformation employed by FeLV and other oncogenic retroviruses has provided as much information on the regulation of eukaryotic cell growth and differentiation as it has about cancer. The recognition that a cancer has a viral cause opens up the possibility of novel treatments that spare the host from cytotoxic side-effects by specifically targeting the virus, or the host's immune response to it. The ultimate prize for viral-associated cancers is their prevention. Vaccination and changes in management practices have seen the global prevalence of FeLV infection fall and, with it, the incidence of FeLV-related cancers. Remarkably, in the face of this success, the prevalence of feline lymphoma remains high. At least one other virus, the lentivirus feline immunodeficiency virus (FIV), accounts for some of these cases. Transformation by FIV involves incompletely understood mechanisms that are distinct from those employed by FeLV. This review will focus on the current understanding of FeLV-associated and FIV-associated lymphoma and consider whether yet more viral aetiologies could be waiting to be discovered. PMID:24928422

  8. Selection of functional tRNA primers and primer binding site sequences from a retroviral combinatorial library: identification of new functional tRNA primers in murine leukemia virus replication

    PubMed Central

    Lund, Anders H.; Duch, Mogens; Pedersen, Finn Skou

    2000-01-01

    Retroviral reverse transcription is initiated from a cellular tRNA molecule and all known exogenous isolates of murine leukemia virus utilise a tRNAPro molecule. While several studies suggest flexibility in murine leukemia virus primer utilisation, studies on human immunodeficiency virus and avian retroviruses have revealed evidence of molecular adaptation towards the specific tRNA isoacceptor used as replication primer. In this study, murine leukemia virus tRNA utilisation is investigated by in vivo screening of a retroviral vector combinatorial library with randomised primer binding sites. While most of the selected primer binding sites are complementary to the 3′-end of tRNAPro, we also retrieved PBS sequences matching four other tRNA molecules and demonstrate that Akv murine leukemia virus vectors may efficiently replicate using tRNAArg(CCU), tRNAPhe(GAA) and a hitherto unknown human tRNASer(CGA). PMID:10637332

  9. Synthesis and assembly of retrovirus Gag precursors into immature capsids in vitro.

    PubMed Central

    Sakalian, M; Parker, S D; Weldon, R A; Hunter, E

    1996-01-01

    The assembly of retroviral particles is mediated by the product of the gag gene; no other retroviral gene products are necessary for this process. While most retroviruses assemble their capsids at the plasma membrane, viruses of the type D class preassemble immature capsids within the cytoplasm of infected cells. This has allowed us to determine whether immature capsids of the prototypical type D retrovirus, Mason-Pfizer monkey virus (M-PMV), can assemble in a cell-free protein synthesis system. We report here that assembly of M-PMV Gag precursor proteins can occur in this in vitro system. Synthesized particles sediment in isopycnic gradients to the appropriate density and in thin-section electron micrographs have a size and appearance consistent with those of immature retrovirus capsids. The in vitro system described in this report appears to faithfully mimic the process of assembly which occurs in the host cell cytoplasm, since M-PMV gag mutants defective in in vivo assembly also fail to assemble in vitro. Likewise, the Gag precursor proteins of retroviruses that undergo type C morphogenesis, Rous sarcoma virus and human immunodeficiency virus, which do not preassemble capsids in vivo, fail to assemble particles in this system. Additionally, we demonstrate, with the use of anti-Gag antibodies, that this cell-free system can be utilized for analysis in vitro of potential inhibitors of retrovirus assembly. PMID:8648705

  10. High Expression of Endogenous Retroviral Envelope Gene in the Equine Fetal Part of the Placenta

    PubMed Central

    Stefanetti, Valentina; Marenzoni, Maria Luisa; Passamonti, Fabrizio; Cappelli, Katia; Garcia-Etxebarria, Koldo; Coletti, Mauro; Capomaccio, Stefano

    2016-01-01

    Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses that have co-evolved with vertebrate genomes for millions of years. Previous studies have identified the envelope (env) protein genes of retroviral origin preferentially expressed in the placenta which suggests a role in placentation based on their membrane fusogenic capacity and therefore they have been named syncytins. Until now, all the characterized syncytins have been associated with three invasive placentation types: the endotheliochorial (Carnivora), the synepitheliochorial (Ruminantia), and the hemochorial placentation (human, mouse) where they play a role in the syncytiotrophoblast formation. The purpose of the present study was to evaluate whether EqERV env RNA is expressed in horse tissues as well and investigate if the horse, possessing an epitheliochorial placenta, has “captured” a common retroviral env gene with syncytin-like properties in placental tissues. Interestingly, although in the equine placenta there is no syncytiotrophoblast layer at the maternal-fetal interface, our results showed that EqERV env RNA is highly expressed at that level, as expected for a candidate syncytin-like gene but with reduced abundance in the other somatic tissues (nearly 30-fold lower) thus suggesting a possible role in the placental tissue. Although the horse is one of the few domestic animals with a sequenced genome, few studies have been conducted about the EqERV and their expression in placental tissue has never been investigated. PMID:27176223

  11. High Expression of Endogenous Retroviral Envelope Gene in the Equine Fetal Part of the Placenta.

    PubMed

    Stefanetti, Valentina; Marenzoni, Maria Luisa; Passamonti, Fabrizio; Cappelli, Katia; Garcia-Etxebarria, Koldo; Coletti, Mauro; Capomaccio, Stefano

    2016-01-01

    Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses that have co-evolved with vertebrate genomes for millions of years. Previous studies have identified the envelope (env) protein genes of retroviral origin preferentially expressed in the placenta which suggests a role in placentation based on their membrane fusogenic capacity and therefore they have been named syncytins. Until now, all the characterized syncytins have been associated with three invasive placentation types: the endotheliochorial (Carnivora), the synepitheliochorial (Ruminantia), and the hemochorial placentation (human, mouse) where they play a role in the syncytiotrophoblast formation. The purpose of the present study was to evaluate whether EqERV env RNA is expressed in horse tissues as well and investigate if the horse, possessing an epitheliochorial placenta, has "captured" a common retroviral env gene with syncytin-like properties in placental tissues. Interestingly, although in the equine placenta there is no syncytiotrophoblast layer at the maternal-fetal interface, our results showed that EqERV env RNA is highly expressed at that level, as expected for a candidate syncytin-like gene but with reduced abundance in the other somatic tissues (nearly 30-fold lower) thus suggesting a possible role in the placental tissue. Although the horse is one of the few domestic animals with a sequenced genome, few studies have been conducted about the EqERV and their expression in placental tissue has never been investigated. PMID:27176223

  12. Endogenous rhythms influence interpersonal synchrony.

    PubMed

    Zamm, Anna; Wellman, Chelsea; Palmer, Caroline

    2016-05-01

    Interpersonal synchrony, the temporal coordination of actions between individuals, is fundamental to social behaviors from conversational speech to dance and music-making. Animal models indicate constraints on synchrony that arise from endogenous rhythms: Intrinsic periodic behaviors or processes that continue in the absence of change in external stimulus conditions. We report evidence for a direct causal link between endogenous rhythms and interpersonal synchrony in a music performance task, which places high demands on temporal coordination. We first establish that endogenous rhythms, measured by spontaneous rates of individual performance, are stable within individuals across stimulus materials, limb movements, and time points. We then test a causal link between endogenous rhythms and interpersonal synchrony by pairing each musician with a partner who is either matched or mismatched in spontaneous rate and by measuring their joint behavior up to 1 year later. Partners performed melodies together, using either the same or different hands. Partners who were matched for spontaneous rate showed greater interpersonal synchrony in joint performance than mismatched partners, regardless of hand used. Endogenous rhythms offer potential to predict optimal group membership in joint behaviors that require temporal coordination. (PsycINFO Database Record PMID:26820249

  13. Direct transformation of rodent fibroblasts by jaagsiekte sheep retrovirus DNA

    PubMed Central

    Maeda, Naoyoshi; Palmarini, Massimo; Murgia, Claudio; Fan, Hung

    2001-01-01

    Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary carcinoma, a unique animal model for human bronchioalveolar carcinoma. We previously isolated a JSRV proviral clone and showed that it was both infectious and oncogenic. Thus JSRV is necessary and sufficient for the development of ovine pulmonary carcinoma, but no data are available on the mechanisms of transformation. Inspection of the JSRV genome reveals standard retroviral genes, but no evidence for a viral oncogene. However, an alternate ORF in pol (orf-x) might be a candidate for a transforming gene. We tested whether the JSRV genome might encode a transforming gene by transfecting an expression plasmid for JSRV [pCMVJS21, driven by the cytomegalovirus (CMV) immediate early promoter] into mouse NIH 3T3 cells. Foci of transformed cells appeared in the transfected cultures 2–3 weeks posttransfection; cloned transformants showed anchorage independence for growth, and they expressed JSRV RNA. These results indicate that the JRSV genome contains information with direct transforming potential for NIH 3T3 cells. Transfection of a mutated version of pCMVJS21 in which the orf-x protein was terminated by two stop codons also gave transformed foci. Thus, orf-x was eliminated as the candidate transforming gene. In addition, another derivative of pCMVJS21 (pCMVJS21ΔGP) in which the gag, pol (and orf-x) coding sequences were deleted also gave transformed foci. These results indicate that the envelope gene carries the transforming potential. This is an unusual example of a native retroviral structural protein with transformation potential. PMID:11296288

  14. Endogenous Hepatitis C Virus Homolog Fragments in European Rabbit and Hare Genomes Replicate in Cell Culture

    PubMed Central

    Silva, Eliane; Marques, Sara; Osório, Hugo; Carvalheira, Júlio; Thompson, Gertrude

    2012-01-01

    Endogenous retroviruses, non-retroviral RNA viruses and DNA viruses have been found in the mammalian genomes. The origin of Hepatitis C virus (HCV), the major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma in humans, remains unclear since its discovery. Here we show that fragments homologous to HCV structural and non-structural (NS) proteins present in the European rabbit (Oryctolagus cuniculus) and hare (Lepus europaeus) genomes replicate in bovine cell cultures. The HCV genomic homolog fragments were demonstrated by RT-PCR, PCR, mass spectrometry, and replication in bovine cell cultures by immunofluorescence assay (IFA) and immunogold electron microscopy (IEM) using specific MAbs for HCV NS3, NS4A, and NS5 proteins. These findings may lead to novel research approaches on the HCV origin, genesis, evolution and diversity. PMID:23185448

  15. Nematode endogenous small RNA pathways

    PubMed Central

    Hoogstrate, Suzanne W; Volkers, Rita JM; Sterken, Mark G; Kammenga, Jan E; Snoek, L Basten

    2014-01-01

    The discovery of small RNA silencing pathways has greatly extended our knowledge of gene regulation. Small RNAs have been presumed to play a role in every field of biology because they affect many biological processes via regulation of gene expression and chromatin remodeling. Most well-known examples of affected processes are development, fertility, and maintenance of genome stability. Here we review the role of the three main endogenous small RNA silencing pathways in Caenorhabditis elegans: microRNAs, endogenous small interfering RNAs, and PIWI-interacting RNAs. After providing an entry-level overview on how these pathways function, we discuss research on other nematode species providing insight into the evolution of these small RNA pathways. In understanding the differences between the endogenous small RNA pathways and their evolution, a more comprehensive picture is formed of the functions and effects of small RNAs. PMID:25340013

  16. Stability analysis of simple models for immune cells interacting with normal pathogens and immune system retroviruses.

    PubMed Central

    Reibnegger, G; Fuchs, D; Hausen, A; Werner, E R; Werner-Felmayer, G; Dierich, M P; Wachter, H

    1989-01-01

    A mathematical analysis is presented for several simple dynamical systems that might be considered as crude descriptions for the situation when an immune system retrovirus, immune cells, and normal autonomously replicating pathogens interact. By stability analysis of the steady-state solutions, the destabilizing effect of the immune system retrovirus is described. The qualitative behavior of the solutions depending on the system parameters is analyzed in terms of trajectories moving in a phase space in which the axes are defined by the population numbers of the interacting biological entities. PMID:2522657

  17. Fate of the surface protein gp70 during entry of retrovirus into mouse fibroblasts

    SciTech Connect

    Andersen, K.B.

    1985-04-15

    The kinetics of the viral surface protein gp70 and the viral core proteins p30 and p15C were followed during retrovirus entry into mouse fibroblasts. All three proteins were internalized, but whereas essentially all the gp70 was degraded, approximately one-third of the core proteins remained stable in the cells. These diverging routes of the different proteins are in agreement with the proposed route, that retrovirus enters the cells by endocytosis followed by a membrane fusion between the virus membrane and the vesicle membrane.

  18. Effect of pentosan polysulfate (SP 54) on the reverse transcriptase activity of several retroviruses.

    PubMed

    Sydow, G; Klöcking, H P

    1987-01-01

    Pentosan polysulfate (SP 54), a low molecular weight sulfated polysaccharide, was studied in vitro for its effect on the reverse transcriptase activity of seven retroviruses. Six of them possess an enzyme with high sensitivity against SP 54, while the enzyme of one virus (bovine leucosis virus) proved to be insensitive within the concentration range tested. In comparison with other polyanionic compounds so far tested, SP 54 seems to be one of the most active in vitro inhibitors of retrovirus-specific reverse transcriptase. PMID:2445339

  19. Quantitative analysis of endogenous compounds.

    PubMed

    Thakare, Rhishikesh; Chhonker, Yashpal S; Gautam, Nagsen; Alamoudi, Jawaher Abdullah; Alnouti, Yazen

    2016-09-01

    Accurate quantitative analysis of endogenous analytes is essential for several clinical and non-clinical applications. LC-MS/MS is the technique of choice for quantitative analyses. Absolute quantification by LC/MS requires preparing standard curves in the same matrix as the study samples so that the matrix effect and the extraction efficiency for analytes are the same in both the standard and study samples. However, by definition, analyte-free biological matrices do not exist for endogenous compounds. To address the lack of blank matrices for the quantification of endogenous compounds by LC-MS/MS, four approaches are used including the standard addition, the background subtraction, the surrogate matrix, and the surrogate analyte methods. This review article presents an overview these approaches, cite and summarize their applications, and compare their advantages and disadvantages. In addition, we discuss in details, validation requirements and compatibility with FDA guidelines to ensure method reliability in quantifying endogenous compounds. The standard addition, background subtraction, and the surrogate analyte approaches allow the use of the same matrix for the calibration curve as the one to be analyzed in the test samples. However, in the surrogate matrix approach, various matrices such as artificial, stripped, and neat matrices are used as surrogate matrices for the actual matrix of study samples. For the surrogate analyte approach, it is required to demonstrate similarity in matrix effect and recovery between surrogate and authentic endogenous analytes. Similarly, for the surrogate matrix approach, it is required to demonstrate similar matrix effect and extraction recovery in both the surrogate and original matrices. All these methods represent indirect approaches to quantify endogenous compounds and regardless of what approach is followed, it has to be shown that none of the validation criteria have been compromised due to the indirect analyses. PMID

  20. [Endogenous hyperlactatemia and insulin secretion].

    PubMed

    Ribes, G; Valette, G; Lignon, F; Loubatières-Mariani, M M

    1978-01-01

    In the normal anesthetized dog, the endogenous hyperlactatemia induced either by intense muscular work or by a high dose of phenformin (20 mg/kg subtucaneously) is followed by an increase in the pancreaticoduodenal insulin output. A previous perfusion of sodium dichloroacetate (50 mg/kg. h) opposes the hyperlactatemia, and reduces or suppresses the increase in insulin output. PMID:150887

  1. Mutational effects of retrovirus insertion on the genome of V79 cells by an attenuated retrovirus vector: implications for gene therapy.

    PubMed

    Themis, M; May, D; Coutelle, C; Newbold, R F

    2003-09-01

    Attenuated retroviruses are currently the most widely used vectors in clinical gene therapy because of their potential to effect stable and permanent gene transfer. Since gene delivery is accompanied by random insertion of foreign genetic material into the recipient chromosomal DNA, the potential for insertional mutagenesis exists. In this study, we used a defective retrovirus vector containing a selectable marker, the hygromycin phosphotransferase gene, to investigate the mutagenic effects of vector integration on the mammalian genome. V79 Chinese hamster cells were infected with virus supernatants or by coculture with virus producer cells, and provirus insertion events occurred at low and high frequencies, respectively. The frequency of hprt mutagenesis was increased by a factor of 2.3 over the spontaneous hprt mutation frequency only following multiple provirus insertions/cell genome. Multiple provirus insertions (>3/genome) resulted in instability at the hprt locus in 63% of the virally induced hprt mutants, as indicated by rearrangements at the molecular level, whereas no rearrangements were found when the provirus copy number was 1-2/genome. To demonstrate direct proviral involvement in mutagenesis, the defective MLV vector was retrieved along with flanking genomic hprt sequences from one mutant, and localized within intron 5 of the hprt gene. These data suggest that provirus copy number is a key factor when considering the potential hazards of using retrovirus vectors for gene therapy. PMID:12923569

  2. Discovery of a novel retrovirus sequence in an Australian native rodent (Melomys burtoni): a putative link between gibbon ape leukemia virus and koala retrovirus.

    PubMed

    Simmons, Greg; Clarke, Daniel; McKee, Jeff; Young, Paul; Meers, Joanne

    2014-01-01

    Gibbon ape leukaemia virus (GALV) and koala retrovirus (KoRV) share a remarkably close sequence identity despite the fact that they occur in distantly related mammals on different continents. It has previously been suggested that infection of their respective hosts may have occurred as a result of a species jump from another, as yet unidentified vertebrate host. To investigate possible sources of these retroviruses in the Australian context, DNA samples were obtained from 42 vertebrate species and screened using PCR in order to detect proviral sequences closely related to KoRV and GALV. Four proviral partial sequences totalling 2880 bases which share a strong similarity with KoRV and GALV were detected in DNA from a native Australian rodent, the grassland melomys, Melomys burtoni. We have designated this novel gammaretrovirus Melomys burtoni retrovirus (MbRV). The concatenated nucleotide sequence of MbRV shares 93% identity with the corresponding sequence from GALV-SEATO and 83% identity with KoRV. The geographic ranges of the grassland melomys and of the koala partially overlap. Thus a species jump by MbRV from melomys to koalas is conceivable. However the genus Melomys does not occur in mainland South East Asia and so it appears most likely that another as yet unidentified host was the source of GALV. PMID:25251014

  3. Tetherin/BST-2 promotes dendritic cell activation and function during acute retrovirus infection

    PubMed Central

    Li, Sam X.; Barrett, Bradley S.; Guo, Kejun; Kassiotis, George; Hasenkrug, Kim J.; Dittmer, Ulf; Gibbert, Kathrin; Santiago, Mario L.

    2016-01-01

    Tetherin/BST-2 is a host restriction factor that inhibits retrovirus release from infected cells in vitro by tethering nascent virions to the plasma membrane. However, contradictory data exists on whether Tetherin inhibits acute retrovirus infection in vivo. Previously, we reported that Tetherin-mediated inhibition of Friend retrovirus (FV) replication at 2 weeks post-infection correlated with stronger natural killer, CD4+ T and CD8+ T cell responses. Here, we further investigated the role of Tetherin in counteracting retrovirus replication in vivo. FV infection levels were similar between wild-type (WT) and Tetherin KO mice at 3 to 7 days post-infection despite removal of a potent restriction factor, Apobec3/Rfv3. However, during this phase of acute infection, Tetherin enhanced myeloid dendritic cell (DC) function. DCs from infected, but not uninfected, WT mice expressed significantly higher MHC class II and the co-stimulatory molecule CD80 compared to Tetherin KO DCs. Tetherin-associated DC activation during acute FV infection correlated with stronger NK cell responses. Furthermore, Tetherin+ DCs from FV-infected mice more strongly stimulated FV-specific CD4+ T cells ex vivo compared to Tetherin KO DCs. The results link the antiretroviral and immunomodulatory activity of Tetherin in vivo to improved DC activation and MHC class II antigen presentation. PMID:26846717

  4. 75 FR 79006 - Submission for OMB Review; Comment Request; Transfusion-Transmitted Retrovirus and Hepatitis...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-17

    ...- Transmitted Retrovirus and Hepatitis Virus Rates and Risk Factors: Improving the Safety of the U.S. Blood... Reduction Act of 1995, the National Heart, Lung, and Blood Institute (NHLBI), the National Institutes of.... blood supply through hemovigilance. Type of Information Collection Request: NEW. Need and Use...

  5. 75 FR 59724 - Proposed Collection; Comment Request; Transfusion-Transmitted Retrovirus and Hepatitis Virus...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ...-Transmitted Retrovirus and Hepatitis Virus Rates and Risk Factors: Improving the Safety of the U.S. Blood..., the National Heart, Lung, and Blood Institute (NHLBI), the National Institutes of Health (NIH), will... and risk factors: Improving the safety of the U.S. blood supply through hemovigilance. Type...

  6. Upregulating endogenous genes by an RNA-programmable artificial transactivator

    PubMed Central

    Fimiani, Cristina; Goina, Elisa; Mallamaci, Antonello

    2015-01-01

    To promote expression of endogenous genes ad libitum, we developed a novel, programmable transcription factor prototype. Kept together via an MS2 coat protein/RNA interface, it includes a fixed, polypeptidic transactivating domain and a variable RNA domain that recognizes the desired gene. Thanks to this device, we specifically upregulated five genes, in cell lines and primary cultures of murine pallial precursors. Gene upregulation was small, however sufficient to robustly inhibit neuronal differentiation. The transactivator interacted with target gene chromatin via its RNA cofactor. Its activity was restricted to cells in which the target gene is normally transcribed. Our device might be useful for specific applications. However for this purpose, it will require an improvement of its transactivation power as well as a better characterization of its target specificity and mechanism of action. PMID:26152305

  7. Insights into the nuclear export of murine leukemia virus intron-containing RNA

    PubMed Central

    Pessel-Vivares, Lucie; Houzet, Laurent; Lainé, Sébastien; Mougel, Marylène

    2015-01-01

    The retroviral genome consists of an intron-containing transcript that has essential cytoplasmic functions in the infected cell. This viral transcript can escape splicing, circumvent the nuclear checkpoint mechanisms and be transported to the cytoplasm by hijacking the host machinery. Once in the cytoplasm, viral unspliced RNA acts as mRNA to be translated and as genomic RNA to be packaged into nascent viruses. The murine leukemia virus (MLV) is among the first retroviruses discovered and is classified as simple Retroviridae due to its minimal encoding capacity. The oncogenic and transduction abilities of MLV are extensively studied, whereas surprisingly the crucial step of its nuclear export has remained unsolved until 2014. Recent work has revealed the recruitment by MLV of the cellular NXF1/Tap-dependent pathway for export. Unconventionally, MLV uses of Tap to export both spliced and unspliced viral RNAs. Unlike other retroviruses, MLV does not harbor a unique RNA signal for export. Indeed, multiple sequences throughout the MLV genome appear to promote export of the unspliced MLV RNA. We review here the current understanding of the export mechanism and highlight the determinants that influence MLV export. As the molecular mechanism of MLV export is elucidated, we will gain insight into the contribution of the export pathway to the cytoplasmic fate of the viral RNA. PMID:26158194

  8. Single-step conversion of cells to retrovirus vector producers with herpes simplex virus-Epstein-Barr virus hybrid amplicons.

    PubMed

    Sena-Esteves, M; Saeki, Y; Camp, S M; Chiocca, E A; Breakefield, X O

    1999-12-01

    We report here on the development and characterization of a novel herpes simplex virus type 1 (HSV-1) amplicon-based vector system which takes advantage of the host range and retention properties of HSV-Epstein-Barr virus (EBV) hybrid amplicons to efficiently convert cells to retrovirus vector producer cells after single-step transduction. The retrovirus genes gag-pol and env (GPE) and retroviral vector sequences were modified to minimize sequence overlap and cloned into an HSV-EBV hybrid amplicon. Retrovirus expression cassettes were used to generate the HSV-EBV-retrovirus hybrid vectors, HERE and HERA, which code for the ecotropic and the amphotropic envelopes, respectively. Retrovirus vector sequences encoding lacZ were cloned downstream from the GPE expression unit. Transfection of 293T/17 cells with amplicon plasmids yielded retrovirus titers between 10(6) and 10(7) transducing units/ml, while infection of the same cells with amplicon vectors generated maximum titers 1 order of magnitude lower. Retrovirus titers were dependent on the extent of transduction by amplicon vectors for the same cell line, but different cell lines displayed varying capacities to produce retrovirus vectors even at the same transduction efficiencies. Infection of human and dog primary gliomas with this system resulted in the production of retrovirus vectors for more than 1 week and the long-term retention and increase in transgene activity over time in these cell populations. Although the efficiency of this system still has to be determined in vivo, many applications are foreseeable for this approach to gene delivery. PMID:10559361

  9. Endogenous opiates and behavior: 2014.

    PubMed

    Bodnar, Richard J

    2016-01-01

    This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular

  10. Human APOBEC3G incorporation into murine leukemia virus particles

    SciTech Connect

    Kremer, Melanie; Schnierle, Barbara S. . E-mail: schba@pei.de

    2005-06-20

    The human APOBEC3G protein exhibits broad antiretroviral activity against a variety of retroviruses. It is packaged into viral particles and executes its antiviral function in the target cell. The packaging of APOBEC3G into different viral particles requires a mechanism that confers this promiscuity. Here, APOBEC3G incorporation into murine leukemia virus (MLV) was studied using retroviral vectors. APOBEC3G uptake did not require either its cytidine deaminase activity or the presence of a retroviral vector genome. Results from immunoprecipitation and co-localization studies of APOBEC3G with a MLV Gag-CFP (cyan fluorescent protein) fusion protein imply an interaction between both proteins. RNase A treatment did not inhibit the co-precipitation of Gag-CFP and APOBEC3G, suggesting that the interaction is RNA independent. Like human immunodeficiency virus (HIV) Gag, the MLV Gag precursor protein appears to interact with APOBEC3G, indicating that Gag contains conserved structures which are used to encapsidate APOBEC3G into different retroviral particles.

  11. Mechanical Properties of Murine Leukemia Virus Particles: Effect of Maturation

    PubMed Central

    Kol, Nitzan; Gladnikoff, Micha; Barlam, David; Shneck, Roni Z.; Rein, Alan; Rousso, Itay

    2006-01-01

    After budding from the host cell, retroviruses undergo a process of internal reorganization called maturation, which is prerequisite to infectivity. Viral maturation is accompanied by dramatic morphological changes, which are poorly understood in physical/mechanistic terms. Here, we study the mechanical properties of live mature and immature murine leukemia virus particles by indentation-type experiments conducted with an atomic force microscope tip. We find that both mature and immature particles have an elastic shell. Strikingly, the virus shell is twofold stiffer in the immature (0.68 N/m) than the mature (0.31 N/m) form. However, finite-element simulation shows that the average Young's modulus of the immature form is more than fourfold lower than that of the mature form. This finding suggests that per length unit, the protein-protein interactions in the mature shell are stronger than those in the immature shell. We also show that the mature virus shell is brittle, since it can be broken by application of large loading forces, by firm attachment to a substrate, or by repeated application of force. Our results are the first analysis of the mechanical properties of an animal virus, and demonstrate a linkage between virus morphology and mechanical properties. PMID:16632508

  12. Endogenous Mechanisms of Cardiac Regeneration.

    PubMed

    Xiang, M S W; Kikuchi, K

    2016-01-01

    Zebrafish possess a remarkable capacity for cardiac regeneration throughout their lifetime, providing a model for investigating endogenous cellular and molecular mechanisms regulating myocardial regeneration. By contrast, adult mammals have an extremely limited capacity for cardiac regeneration, contributing to mortality and morbidity from cardiac diseases such as myocardial infarction and heart failure. However, the viewpoint of the mammalian heart as a postmitotic organ was recently revised based on findings that the mammalian heart contains multiple undifferentiated cell types with cardiogenic potential as well as a robust regenerative capacity during a short period early in life. Although it occurs at an extremely low level, continuous cardiomyocyte turnover has been detected in adult mouse and human hearts, which could potentially be enhanced to restore lost myocardium in damaged human hearts. This review summarizes and discusses recent advances in the understanding of endogenous mechanisms of cardiac regeneration. PMID:27572127

  13. Endogenous opiates and behavior: 2004.

    PubMed

    Bodnar, Richard J; Klein, Gad E

    2005-12-01

    This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses. PMID:16039752

  14. Endogenous opiates and behavior: 2013.

    PubMed

    Bodnar, Richard J

    2014-12-01

    This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses. PMID:25263178

  15. Endogenous opiates and behavior: 2007.

    PubMed

    Bodnar, Richard J

    2008-12-01

    This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses. PMID:18851999

  16. Endogenous respiration of Polyporus sulphureus

    SciTech Connect

    Li, S.M.W.; Siehr, D.J.

    1980-01-01

    Thirty percent of the dry weight of the basidiomycete Polyporus sulphureus is triterpenoid acid. The endogenous respiratory quotient of this organism is 0.8 indicating that the triterpenoid is being used as an endogenous storage material. Monosaccharides did not seem to be utilized as exogenous substrates but Krebs-cycle intermediates stimulated oxygen uptake. Pyruvic acid inhibited oxygen uptake. Studies with /sup 14/C-labeled glucose indicated that 27% of the glucose was metabolized by way of glycolysis. The hexose-monophosphate pathway was the major metabolic path for the utilization of glucose. Despite the fact that P. sulphureus is associated with brown rot, its carbon metabolism suggests that it utilizes substances associated with the degradation of lignin more readily than it does glucose.

  17. New Class of Leukemogenic Ecotropic Recombinant Murine Leukemia Virus Isolated from Radiation-Induced Thymomas of C57BL/6 Mice

    PubMed Central

    Rassart, E.; Sankar-Mistry, P.; Lemay, G.; DesGroseillers, L.; Jolicoeur, P.

    1983-01-01

    We previously reported the establishment of several lymphoid cell lines from X-ray-induced thymomas of C57BL/Ka mice, and all, except one, produce retroviruses (P. Sankar-Mistry and P. Jolicoeur, J. Virol.35:270-275, 1980). Biological characterization of five of these new primary radiation leukemia viruses (RadLVs) indicated that they had a B-tropic, fibrotropic, and ecotropic host range and were leukemogenic when reinjected into C57BL/Ka newborn mice. The leukemogenic potential of one isolate (G6T2) was further assessed and shown to be retained after prolonged passaging on fibroblasts in vitro. Restriction endonuclease analysis of the DNA of four of our new RadLV isolates (G6T2, Ti-7, Ti-8, and Ti-9) revealed that G6T2 and Ti-7 murine leukemia virus (MuLV) genomes had identical restriction maps, whereas Ti-8 and Ti-9 genomes were different from each other and from the G6T2 and Ti-7 genomes. The physical maps of these genomes were similar to that of known ecotropic MuLV genomes (including the C57BL/Ka endogenous ecotropic MuLV) within their long terminal repeats, env, the right portion of pol, and the left portion of gag. However, a region covering the end of gag and the beginning of pol was different and showed several similarities with xenotropic MuLV genomes of BALB/c, AKR, and C58 mice previously mapped. Our results suggest that these primary RadLV genomes are recombinants between the parental ecotropic MuLV genome and a nonecotropic (xenotropic) sequence. This nonecotropic gag-pol region might be important in conferring the leukemogenic potential to these isolates. Therefore, these RadLVs appear to form a new class of leukemogenic recombinant MuLVs recovered from leukemic tissues of mice. They appear to be distinct from the recombinant AKR mink cell focus-inducing MuLVs which have a dual-tropic host range and harbor xenotropic env sequences. To further study the leukemogenic potential of these RadLVs, the genome of one of them (G6T2) was cloned in Charon 21A

  18. A novel model of SCID-X1 reconstitution reveals predisposition to retrovirus-induced lymphoma but no evidence of gammaC gene oncogenicity.

    PubMed

    Scobie, Linda; Hector, Ralph D; Grant, Louise; Bell, Margaret; Nielsen, Anne A; Meikle, Sharon; Philbey, Adrian; Philbey, Adrain; Thrasher, Adrian J; Thrasher, Adrain J; Cameron, Ewan R; Blyth, Karen; Neil, James C

    2009-06-01

    The emergence of leukemia following gene transfer to restore common cytokine receptor gamma chain (gammaC) function in X-linked severe combined immunodeficiency (SCID-X1) has raised important questions with respect to gene therapy safety. To explore the risk factors involved, we tested the oncogenic potential of human gammaC in new strains of transgenic mice expressing the gene under the control of the CD2 promoter and locus control region (LCR). These mice demonstrated mildly perturbed T-cell development, with an increased proportion of thymic CD8 cells, but showed no predisposition to tumor development even on highly tumor prone backgrounds or after gamma-retrovirus infection. The human CD2-gammaC transgene rescued T and B-cell development in gammaC(-/-) mice but with an age-related delay, mimicking postnatal reconstitution in SCID-X1 gene therapy subjects. However, we noted that gammaC(-/-) mice are acutely susceptible to murine leukemia virus (MLV) leukemogenesis, and that this trait was not corrected by the gammaC transgene. We conclude that the SCID-X1 phenotype can be corrected safely by stable ectopic expression of gammaC and that the transgene is not significantly oncogenic when expressed in this context. However, an underlying predisposition conferred by the SCID-X1 background appears to collaborate with insertional mutagenesis to increase the risk of tumor development. PMID:19337236

  19. Infection with human retroviruses other than HIV-1: HIV-2, HTLV-1, HTLV-2, HTLV-3 and HTLV-4.

    PubMed

    Nicolás, David; Ambrosioni, Juan; Paredes, Roger; Marcos, M Ángeles; Manzardo, Christian; Moreno, Asunción; Miró, José M

    2015-08-01

    HIV-1 is the most prevalent retrovirus, with over 30 million people infected worldwide. Nevertheless, infection caused by other human retroviruses like HIV-2, HTLV-1, HTLV-2, HTLV-3 and HTLV-4 is gaining importance. Initially confined to specific geographical areas, HIV-2, HTLV-1 and HTLV-2 are becoming a major concern in non-endemic countries due to international migration flows. Clinical manifestations of retroviruses range from asymptomatic carriers to life-threatening conditions, such as AIDS in HIV-2 infection or adult T-cell lymphoma/leukemia or tropical spastic paraparesis in HTLV-1 infection. HIV-2 is naturally resistant to some antiretrovirals frequently used to treat HIV-1 infection, but it does have effective antiretroviral therapy options. Unfortunately, HTLV still has limited therapeutic options. In this article, we will review the epidemiological, clinical, diagnostic, pathogenic and therapeutic aspects of infections caused by these human retroviruses. PMID:26112187

  20. Endogenous New World primate type C viruses isolated from owl monkey (Aotus trivirgatus) kidney cell line.

    PubMed Central

    Todaro, G J; Sherr, C J; Sen, A; King, N; Daniel, M D; Fleckenstein, B

    1978-01-01

    A type C virus (OMC-1) detected in a culture of owl monkey kidney cells resembled typical type C viruses morphologically, but was slightly larger than previously characterized mammalian type C viruses. OMC-1 can be transmitted to bat lung cells and cat embryo fibroblasts. The virions band at a density of 1.16 g/ml in isopycnic sucrose density gradients and contain reverse transcriptase and a 60-65S RNA genome composed of approximately 32S subunits. The reverse transcriptase is immunologically and biochemically distinct from the polymerases of othe retroviruses. Radioimmunoassays directed to the interspecies antigenic determinants of the major structure proteins of other type C viruses do not detect a related antigen in OMC-1. Nucleic acid hybridization experiments using labeled viral genomic RNA or proviral cDNA transcripts to normal cellular DNA of different species show that OMC-1 is an endogenous virus with multiple virogene copies (20-50 per haploid genome) present in normal owl monkey cells and is distinct from previously isolated type C and D viruses. Sequences related to the OMC-1 genome can be detected in other New World monkeys. Thus, similar to the Old World primates (e.g., baboons as a prototype), the New World monkeys contain endogenous type C viral genes that appear to have been transmitted in the primate germ line. Images PMID:76312

  1. Baton pass hypothesis: successive incorporation of unconserved endogenous retroviral genes for placentation during mammalian evolution.

    PubMed

    Imakawa, Kazuhiko; Nakagawa, So; Miyazawa, Takayuki

    2015-10-01

    It is well accepted that numerous RNAs derived from endogenous retroviruses (ERVs) are expressed in mammalian reproductive structures, particularly in the uterus, trophoblast, and placenta. Syncytin 1 and syncytin 2 in humans and syncytin A and syncytin B in mice are membrane proteins originating from Env genes of ERVs. These ERVs are involved in the fusion of trophoblast cells, resulting in multinucleated syncytiotrophoblast formation. Evidence accumulated indicates that syncytin-like fusogenic proteins are expressed in the placenta of rabbits, dogs/cats, ruminant ungulates, tenrecs, and opossums. The syncytin genes so far characterized are known to be endogenized to the host genome only within the past 12-80 million years, more recently than the appearance of mammalian placentas, estimated to be 160-180 million years ago. We speculate that ERVs including syncytin-like gene variants integrated into mammalian genomes in a locus-specific manner have replaced the genes previously responsible for cell fusion. We therefore propose the 'baton pass' hypothesis, in which multiple successive ERV variants 'take over' cell-fusion roles, resulting in increased trophoblast cell fusion, morphological variations in placental structures, and enhanced reproductive success in placental mammals. PMID:26442811

  2. Vaccination against δ−Retroviruses: The Bovine Leukemia Virus Paradigm

    PubMed Central

    Gutiérrez, Gerónimo; Rodríguez, Sabrina M.; de Brogniez, Alix; Gillet, Nicolas; Golime, Ramarao; Burny, Arsène; Jaworski, Juan-Pablo; Alvarez, Irene; Vagnoni, Lucas; Trono, Karina; Willems, Luc

    2014-01-01

    Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related δ-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly in subtropical areas. HTLV-1 induces a wide spectrum of diseases (e.g., HTLV-associated myelopathy/tropical spastic paraparesis) and leukemia/lymphoma (adult T-cell leukemia). Bovine leukemia virus is a major pathogen of cattle, causing important economic losses due to a reduction in production, export limitations and lymphoma-associated death. In the absence of satisfactory treatment for these diseases and besides the prevention of transmission, the best option to reduce the prevalence of δ-retroviruses is vaccination. Here, we provide an overview of the different vaccination strategies in the BLV model and outline key parameters required for vaccine efficacy. PMID:24956179

  3. Endogenous endostatin inhibits choroidal neovascularization.

    PubMed

    Marneros, Alexander G; She, Haicheng; Zambarakji, Hadi; Hashizume, Hiroya; Connolly, Edward J; Kim, Ivana; Gragoudas, Evangelos S; Miller, Joan W; Olsen, Bjorn R

    2007-12-01

    Endostatin, a fragment of the basement membrane component collagen XVIII, exhibits antiangiogenic properties in vitro and in vivo when high doses are administered. It is not known whether endogenous endostatin at physiological levels has a protective role as an inhibitor of pathological angiogenesis, such as choroidal neovascularization (CNV) in age-related macular degeneration. Using a laser injury model, we induced CNV in mice lacking collagen XVIII/endostatin and in control mice. CNV lesions in mutant mice were approximately 3-fold larger than in control mice and showed increased vascular leakage. These differences were independent of age-related changes at the choroid-retina interface. Ultrastructural analysis of the choroidal vasculature in mutant mice excluded morphological vascular abnormalities as a cause for the larger CNV lesions. When recombinant endostatin was administered to collagen XVIII/endostatin-deficient mice, CNV lesions were similar to those seen in control mice. In control mice treated with recombinant endostatin, CNV lesions were almost undetectable. These findings demonstrate that endogenous endostatin is an inhibitor of induced angiogenesis and that administration of endostatin potently inhibits CNV growth and vascular leakage. Endostatin may have a regulatory role in the pathogenesis of CNV and could be used therapeutically to inhibit growth and leakage of CNV lesions. PMID:17526870

  4. Endogenous opiates and behavior: 2012.

    PubMed

    Bodnar, Richard J

    2013-12-01

    This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:24126281

  5. Endogenous opiates and behavior: 2009.

    PubMed

    Bodnar, Richard J

    2010-12-01

    This paper is the 32nd consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2009 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:20875476

  6. Endogenous opiates and behavior: 2005.

    PubMed

    Bodnar, Richard J; Klein, Gad E

    2006-12-01

    This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17). PMID:16973239

  7. Endogenous opiates and behavior: 2008.

    PubMed

    Bodnar, Richard J

    2009-12-01

    This paper is the 31st consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2008 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:19793543

  8. Endogenous opiates and behavior: 2010.

    PubMed

    Bodnar, Richard J

    2011-12-01

    This paper is the thirty-third consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2010 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17). PMID:21983105

  9. Endogenous opiates and behavior: 2006.

    PubMed

    Bodnar, Richard J

    2007-12-01

    This paper is the 29th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning 30 years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:17949854

  10. Endogenous opiates and behavior: 2011.

    PubMed

    Bodnar, Richard J

    2012-12-01

    This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17). PMID:23041439

  11. Endogenous opiates and behavior: 2002.

    PubMed

    Bodnar, Richard J; Hadjimarkou, Maria M

    2003-08-01

    This paper is the twenty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2002 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:14612197

  12. Endogenous opiates and behavior: 2003.

    PubMed

    Bodnar, Richard J; Klein, Gad E

    2004-12-01

    This paper is the 26th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2003 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:15572211

  13. Endogenous Opiates and Behavior: 2006

    PubMed Central

    Bodnar, Richard J.

    2009-01-01

    This paper is the twenty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning thirty years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:17949854

  14. An endogenous retroviral long terminal repeat is the dominant promoter for human beta1,3-galactosyltransferase 5 in the colon.

    PubMed

    Dunn, Catherine A; Medstrand, Patrik; Mager, Dixie L

    2003-10-28

    LTRs of endogenous retroviruses are known to affect expression of several human genes, typically as a relatively minor alternative promoter. Here, we report that an endogenous retrovirus LTR acts as one of at least two alternative promoters for the human beta1,3-galactosyltransferase 5 gene, involved in type 1 Lewis antigen synthesis, and show that the LTR promoter is most active in the gastrointestinal tract and mammary gland. Indeed, the LTR is the dominant promoter in the colon, indicating that this ancient retroviral element has a major impact on gene expression. Using colorectal cancer cell lines and electrophoretic mobility-shift assays, we found that hepatocyte nuclear factor 1 (HNF-1) binds a site within the retroviral promoter and that expression of HNF-1 and interaction with its binding site correlated with promoter activation. We conclude that HNF-1 is at least partially responsible for the tissue-specific activation of the LTR promoter of human beta 1,3-galactosyltransferase 5. We demonstrate that this tissue-specific transcription factor is implicated in the activation of an LTR gene promoter. PMID:14534330

  15. 5-Azacytidine and RNA secondary structure increase the retrovirus mutation rate.

    PubMed Central

    Pathak, V K; Temin, H M

    1992-01-01

    A broad spectrum of mutations occurs at a high rate during a single round of retrovirus replication (V.K. Pathak and H. M. Temin, Proc. Natl. Acad. Sci. USA 87:6019-6023, 1990). We have now determined that this high rate of spontaneous mutation can be further increased by 5-azacytidine (AZC) treatment or by regions of potential RNA secondary structure. We found a 13-fold increase in the mutation rate after AZC treatment of retrovirus-producing cells and target cells. The AZC-induced substitutions were located at the same target sites as previously identified spontaneous substitutions. The concordance of the AZC-induced and spontaneous substitutions indicates the presence of reverse transcription "pause sites," where the growing point is error prone. An analysis of nucleotides that neighbored substitutions revealed that transversions occur primarily by transient template misalignment, whereas transitions occur primarily by misincorporation. We also introduced a 34-bp potential stem-loop structure as an in-frame insertion within a lacZ alpha gene that was inserted in the long terminal repeat (LTR) U3 region and determined whether this potential secondary structure increased the rate of retrovirus mutations. We found a threefold increase in the retrovirus mutation rate. Fifty-seven of 96 mutations were deletions associated with the potential stem-loop. We also determined that these deletion mutations occurred primarily during minus-strand DNA synthesis by comparing the frequencies of mutations in recovered provirus plasmids containing both LTRs and in provirus plasmids containing only one LTR. PMID:1373201

  16. Retroviruses and retroelements in diseases and in gene therapy: 15 years later.

    PubMed

    Svoboda, Jan

    2011-01-01

    The past 15 years opened new avenues for retrovirus and retroelement research. Not surprisingly, they stemmed from essential knowledge collected in the past, which remains the ground of the present and therefore should be remembered. However, a short supplement of new break-through discoveries and ideas should be recollected. Using selected examples of recent works, I tried to extend and supplement my original article published in Folia Biologica (1996). PMID:21943326

  17. Tetherin promotes the innate and adaptive cell-mediated immune response against retrovirus infection in vivo

    PubMed Central

    Li, Sam X.; Barrett, Bradley S.; Heilman, Karl J.; Messer, Ronald J.; Liberatore, Rachel A.; Bieniasz, Paul D.; Kassiotis, George; Hasenkrug, Kim J.; Santiago, Mario L.

    2014-01-01

    Tetherin/BST-2 is a host restriction factor that could directly inhibit retroviral particle release by tethering nascent virions to the plasma membrane. However, the immunological impact of Tetherin during retrovirus infection remains unknown. We now show that Tetherin influences antiretroviral cell-mediated immune responses. In contrast to the direct antiviral effects of Tetherin, which are dependent on cell surface expression, the immunomodulatory effects are linked to the endocytosis of the molecule. Mice encoding endocytosis-competent C57BL/6 Tetherin exhibited lower viremia and pathology at 7 days post-infection with Friend retrovirus (FV) compared to mice encoding endocytosis-defective NZW/LacJ Tetherin. Notably, antiretroviral protection correlated with stronger NK cell responses. In addition, FV infection levels were significantly lower in wild-type C57BL/6 mice than in Tetherin knock-out mice at 2 weeks post-infection, and antiretroviral protection correlated with stronger NK cell and virus-specific CD8+ T cell responses. The results demonstrate that Tetherin acts as a modulator of the cell-mediated immune response against retrovirus infection in vivo. PMID:24872193

  18. High-frequency deletion in recovered retrovirus vectors containing exogenous DNA with promoters.

    PubMed Central

    Emerman, M; Temin, H M

    1984-01-01

    We previously described infectious retrovirus vectors constructed from spleen necrosis virus which contain the herpes simplex virus thymidine kinase gene and the mouse alpha-globin gene (K. Shimotohno and H. M. Temin, Nature [London] 299:255-268, 1982). In the present study we report that when TK- chicken cells infected with a virus containing the mouse alpha-globin promoter and other 5' noncoding sequences in addition to the alpha-globin coding sequences were selected for thymidine kinase (TK) activity, all virus-producing TK+ cell clones shed virus with a deletion. These deletions were of different sizes and included the mouse alpha-globin coding sequences and the mouse alpha-globin transcriptional promoter. One of the deleted viruses was molecularly cloned. DNA sequencing showed that the deleted sequences are flanked by a short direct repeat. This deleted virus was also shown to have an advantage over the nondeleted parent both in multiplication and in its specific TK-transforming unit titer. In contrast to the results described above, TK+ cell clones established with viruses that contained only the coding sequences from the mouse alpha-globin gene did not delete and were stable over many cell passages. The implications of the high-frequency deletion of the viruses with internal promoters are discussed in terms of the evolution of retroviruses and the construction of retrovirus vectors. Images PMID:6321798

  19. Adaptation of a retrovirus as a eucaryotic vector transmitting the herpes simplex virus thymidine kinase gene

    SciTech Connect

    Tabin, C.J.; Hoffman, J.W.; Goff, S.P.; Weinberg, R.A.

    1982-04-01

    The authors investigated the feasibility of using retroviruses as vectors for transferring DNA sequences into animal cells. The thymidine kinase (tk) gene of herpes simplex virus was chosen as a convenient model. The internal BamHI fragments of a DNA clone of Moloney leukemia virus (MLV) were replaced with a purified BamHI DNA segment containing the tk gene. Chimeric genomes were created carrying the tk insert on both orientations relative to the MLV sequence. Each was transfected into TK/sup -/ cells along with MLV helper virus, and TK/sup +/ colonies were obtained by selection in the presence of hypoxanthine, aminopterin, and thymidine (HAT). Virus collected from TK/sup +/-transformed, MLV producer cells passed the TK/sup +/ phenotype to TK/sup -/ cells. Nonproducer cells were isolated, and TK/sup +/ transducing virus was subsequently rescued from them. The chimeric virus showed single-hit kinetics in infections. Virion and cellular RNA and cellular DNA from infected cells were all shown to contain sequences which hybridized to both MLV- and tk-specific probes. The sizes of these sequences were consistent with those predicted for the chimeric virus. In all respects studied, the chimeric MLV-tk virus behaved like known replication-defective retroviruses. These experiments suggest great general applicability of retroviruses as eucaryotic vectors.

  20. Biochemical and proteomic characterization of retrovirus Gag based microparticles carrying melanoma antigens

    PubMed Central

    Kurg, Reet; Reinsalu, Olavi; Jagur, Sergei; Õunap, Kadri; Võsa, Liisi; Kasvandik, Sergo; Padari, Kärt; Gildemann, Kiira; Ustav, Mart

    2016-01-01

    Extracellular vesicles are membraneous particles released by a variety of cells into the extracellular microenvironment. Retroviruses utilize the cellular vesiculation pathway for virus budding/assembly and the retrovirus Gag protein induces the spontaneous formation of microvesicles or virus-like particles (VLPs) when expressed in the mammalian cells. In this study, five different melanoma antigens, MAGEA4, MAGEA10, MART1, TRP1 and MCAM, were incorporated into the VLPs and their localization within the particles was determined. Our data show that the MAGEA4 and MAGEA10 proteins as well as MCAM are expressed on the surface of VLPs. The compartmentalization of exogenously expressed cancer antigens within the VLPs did not depend on the localization of the protein within the cell. Comparison of the protein content of VLPs by LC-MS/MS-based label-free quantitative proteomics showed that VLPs carrying different cancer antigens are very similar to each other, but differ to some extent from VLPs without recombinant antigen. We suggest that retrovirus Gag based virus-like particles carrying recombinant antigens have a potential to be used in cancer immunotherapy. PMID:27403717

  1. Endogenous opiates and behavior: 2001.

    PubMed

    Bodnar, Richard J; Hadjimarkou, Maria M

    2002-12-01

    This paper is the twenty-fourth installment of the annual review of research concerning the opiate system. It summarizes papers published during 2001 that studied the behavioral effects of the opiate peptides and antagonists. The particular topics covered this year include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology(Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:12535711

  2. Murine leukemia virus envelope gp70 is a shared biomarker for the high-sensitivity quantification of murine tumor burden

    PubMed Central

    Scrimieri, Francesca; Askew, David; Corn, David J; Eid, Saada; Bobanga, Iuliana D; Bjelac, Jaclyn A; Tsao, Matthew L; Allen, Frederick; Othman, Youmna S; Wang, Shih-Chung G; Huang, Alex Y

    2013-01-01

    The preclinical development of anticancer drugs including immunotherapeutics and targeted agents relies on the ability to detect minimal residual tumor burden as a measure of therapeutic efficacy. Real-time quantitative (qPCR) represents an exquisitely sensitive method to perform such an assessment. However, qPCR-based applications are limited by the availability of a genetic defect associated with each tumor model under investigation. Here, we describe an off-the-shelf qPCR-based approach to detect a broad array of commonly used preclinical murine tumor models. In particular, we report that the mRNA coding for the envelope glycoprotein 70 (gp70) encoded by the endogenous murine leukemia virus (MuLV) is universally expressed in 22 murine cancer cell lines of disparate histological origin but is silent in 20 out of 22 normal mouse tissues. Further, we detected the presence of as few as 100 tumor cells in whole lung extracts using qPCR specific for gp70, supporting the notion that this detection approach has a higher sensitivity as compared with traditional tissue histology methods. Although gp70 is expressed in a wide variety of tumor cell lines, it was absent in inflamed tissues, non-transformed cell lines, or pre-cancerous lesions. Having a high-sensitivity biomarker for the detection of a wide range of murine tumor cells that does not require additional genetic manipulations or the knowledge of specific genetic alterations present in a given neoplasm represents a unique experimental tool for investigating metastasis, assessing antitumor therapeutic interventions, and further determining tumor recurrence or minimal residual disease. PMID:24482753

  3. Angiostatin and endostatin: endothelial cell-specific endogenous inhibitors of angiogenesis and tumor growth.

    PubMed

    Sim, B K

    1998-01-01

    Angiostatin and Endostatin are potent inhibitors of angiogenesis. These proteins are endogenously produced and specifically target endothelial cells resulting in angiogenesis inhibition. Recombinant preparations of these proteins inhibit the growth of metastases and regress primary tumors to dormant microscopic lesions. A variety of murine tumors as well as human breast, prostate and colon tumors in human xenograft models regress when treated with Angiostatin or Endostatin. Regression of tumors upon systemic treatment with these proteins is in part due to increased tumor cell apoptosis. Repeated cycles of Endostatin therapy lead to prolonged tumor dormancy without further treatment and are not associated with any apparent toxicity or acquired drug resistance. PMID:14517374

  4. Molecular requirements for immunoglobulin heavy chain constant region gene switch-recombination revealed with switch-substrate retroviruses.

    PubMed

    Ott, D E; Marcu, K B

    1989-01-01

    We have employed a retroviral vector, ZN(Smu/S gamma 2b)tk1, as a means of introducing immunoglobulin heavy chain (IgH) switch (S) region sequences into B cell lines to directly measure their switch-recombinase activities. In an earlier study, we demonstrated that retrovector Smu-S gamma 2b recombination events occurred in two thymidine kinase (tk)-negative murine pre-B cell lines (18-8 and 38B9) upon selection in bromodeoxyuridine (BUdR) media for the loss of an Htk gene inserted in between the vector's Smu and S gamma 2b sequences. Here we have used this assay system to show that the 300-18 murine pre-B cell line possesses a very high level of switch-recombinase activity (greater than 1 event in 2500 cells/generation) while a terminally differentiated, antibody-secreting hybridoma line (A39R 1.1) has no detectable recombinase activity. Both S mu and S gamma 2b segments are required for switch region-mediated deletions. Retrovectors harboring only an Smu segment or an Smu segment and a portion of the murine c-myc gene in place of S gamma 2b sequences were both non-recombinagenic in this assay system. Nucleotide sequence analysis of six retrovector S segment recombinants, recovered from ZN(Smu/S gamma 2b) tk1-infected 18-8 and 39B9 pre-B lines, did not reveal homology at their sites of recombination. We conclude that: (1) S segment repetitive sequences play an essential but indirect role in IgCH gene switch-recombination, which occurs by an illegitimate, non-homologous mechanism; (2) the c-myc gene is not a significant target for switch-recombination; and (3) since endogenous Smu and S gamma 2b rearrangements were not observed in populations and clones of pre-B cells expressing a high level of switch-recombinase activity, multiple factors (presumably contributed in part by the degree of S segment accessibility) in addition to S recombinase activity are required for CH class switching. PMID:2489045

  5. ARHGAP18: an endogenous inhibitor of angiogenesis, limiting tip formation and stabilizing junctions

    PubMed Central

    Chang, Garry HK; Lay, Angelina J; Ting, Ka Ka; Zhao, Yang; Coleman, Paul R; Powter, Elizabeth E; Formaz-Preston, Ann; Jolly, Christopher J; Bower, Neil I; Hogan, Benjamin M; Rinkwitz, Silke; Becker, Thomas S; Vadas, Mathew A; Gamble, Jennifer R

    2014-01-01

    The formation of the vascular network requires a tightly controlled balance of pro-angiogenic and stabilizing signals. Perturbation of this balance can result in dysregulated blood vessel morphogenesis and drive pathologies including cancer. Here, we have identified a novel gene, ARHGAP18, as an endogenous negative regulator of angiogenesis, limiting pro-angiogenic signaling and promoting vascular stability. Loss of ARHGAP18 promotes EC hypersprouting during zebrafish and murine retinal vessel development and enhances tumor vascularization and growth. Endogenous ARHGAP18 acts specifically on RhoC and relocalizes to the angiogenic and destabilized EC junctions in a ROCK dependent manner, where it is important in reaffirming stable EC junctions and suppressing tip cell behavior, at least partially through regulation of tip cell genes, Dll4, Flk-1 and Flt-4. These findings highlight ARHGAP18 as a specific RhoGAP to fine tune vascular morphogenesis, limiting tip cell formation and promoting junctional integrity to stabilize the angiogenic architecture. PMID:25425145

  6. Murine typhus in travelers returning from Indonesia.

    PubMed Central

    Parola, P.; Vogelaers, D.; Roure, C.; Janbon, F.; Raoult, D.

    1998-01-01

    We report the first three documented cases of murine typhus imported into Europe from Indonesia, discuss clues for the diagnosis of the disease, and urge that murine fever be considered in the diagnosis of febrile disease in travelers. PMID:9866749

  7. Antibacterial activity of recombinant murine beta interferon.

    PubMed Central

    Fujiki, T; Tanaka, A

    1988-01-01

    Recombinant murine beta interferon was protective and therapeutic for mice against Listeria monocytogenes infection in vivo. The recombinant murine beta interferon caused enhanced H2O2 release by macrophages in vivo, but not in vitro. PMID:3343048

  8. Immunosuppressive effect of murine cytomegalovirus.

    PubMed Central

    Loh, L; Hudson, J B

    1980-01-01

    Murine cytomegalovirus suppressed the ability of spleen cells to respond to mitogens in vitro. The degree of suppression was proportional to the multiplicity of infection. This effect could not be explained by cytolysis of lymphocytes, an alteration in the kinetics of the response to mitogen, or a direct competition between virions and mitogen molecules for cell-surface receptors. Nor was it due to simple contact between cell and virus, since ultraviolet-inactivated murine cytomegalovirus failed to suppress the response to mitogens. Reconstitution experiments were performed which involved mixing various combinations of infected and uninfected macrophages and lymphocytes. Under these conditions, it was found that the infected macrophages and lymphocytes. Under these conditions, it was found that the infected macrophages had an impaired capacity to mediate the response ot T lymphocytes to concanavalin A. This suggests that murine cytomegalovirus may cause immunosuppression indirectly by interfering with macrophage function. PMID:6244228

  9. Sodium-Dependent myo-Inositol Transporter 1 Is a Cellular Receptor for Mus cervicolor M813 Murine Leukemia Virus

    PubMed Central

    Hein, Sibyll; Prassolov, Vladimir; Zhang, Yuanming; Ivanov, Dmitry; Löhler, Jürgen; Ross, Susan R.; Stocking, Carol

    2003-01-01

    Retrovirus infection is initiated by binding of the surface (SU) portion of the viral envelope glycoprotein (Env) to specific receptors on cells. This binding triggers conformational changes in the transmembrane portion of Env, leading to membrane fusion and cell entry, and is thus a major determinant of retrovirus tissue and species tropism. The M813 murine leukemia virus (MuLV) is a highly fusogenic gammaretrovirus, isolated from Mus cervicolor, whose host range is limited to mouse cells. To delineate the molecular mechanisms of its restricted host range and its high fusogenic potential, we initiated studies to characterize the cell surface protein that mediates M813 infection. Screening of the T31 mouse-hamster radiation hybrid panel for M813 infectivity localized the receptor gene to the distal end of mouse chromosome 16. Expression of one of the likely candidate genes (slc5a3) within this region in human cells conferred susceptibility to both M813 infection and M813-induced fusogenicity. slc5a3 encodes sodium myo-inositol transporter 1 (SMIT1), thus adding another sodium-dependent transporter to the growing list of proteins used by MuLVs for cell entry. Characterization of SMIT1 orthologues in different species identified several amino acid variations within two extracellular loops that may restrict susceptibility to M813 infection. PMID:12719585

  10. Role for a Zinc Finger Protein (Zfp111) in Transformation of 208F Rat Fibroblasts by Jaagsiekte Sheep Retrovirus Envelope Protein

    PubMed Central

    Hsu, Tom; Phung, An; Choe, Kevin; Kim, Jung Woo

    2015-01-01

    ABSTRACT The native envelope gene (env) of Jaagsiekte sheep retrovirus (JSRV) also acts as an oncogene. To investigate the mechanism of transformation, we performed yeast 2-hybrid screening for cellular proteins that interact with Env. Among several candidates, we identified mouse or rat zinc finger protein 111 (zfp111). The interaction between Env and Zfp111 was confirmed through in vivo coimmunoprecipitation assays. Knockdown of endogenous Zfp111 caused a decrease in cell transformation by JSRV Env, while overexpression of Zfp111 increased overall Env transformation, supporting a role for Zfp111 in Env transformation. Knockdown of Zfp111 had no effect on the growth rate of parental rat 208F cells, while it decreased the proliferation rate of JSRV-transformed 208F cells, suggesting that JSRV-transformed cells became dependent on Zfp111. In addition, Zfp111 preferentially bound to a higher-mobility form of JSRV Env that has not been described previously. The higher-mobility form of Env (P70env) was found exclusively in the nuclear fraction, and size of its polypeptide backbone was the same as that of the cytoplasmic Env polyprotein (Pr80env). The differences in glycosylation between the two versions of Env were characterized. These results identify a novel cellular protein, Zfp111, that binds to the JSRV Env protein, and this binding plays a role in Env transformation. These results indicate that JSRV transformation also involves proteins and interactions in the nucleus. IMPORTANCE The envelope protein (Env) of Jaagsiekte sheep retrovirus (JSRV) is an oncogene, but its mechanism of cell transformation is still unclear. Here we identified seven candidate cellular proteins that can interact with JSRV Env by yeast two-hybrid screening. This study focused on one of the seven candidates, zinc finger protein 111 (Zfp111). Zfp111 was shown to interact with JSRV Env in cells and to be involved in JSRV transformation. Moreover, coexpression of JSRV Env and Zfp111 led to the

  11. Endogenous Peer Effects: Fact or Fiction?

    ERIC Educational Resources Information Center

    Yeung, Ryan; Nguyen-Hoang, Phuong

    2016-01-01

    The authors examine endogenous peer effects, which occur when a student's behavior or outcome is a function of the behavior or outcome of his or her peer group. Endogenous peer effects have important implications for educational policies such as busing, school choice and tracking. In this study, the authors quantitatively review the literature on…

  12. Endogenous timing factors in bird migration

    NASA Technical Reports Server (NTRS)

    Gwinner, E. G.

    1972-01-01

    Several species of warbler birds were observed in an effort to determine what initiates and terminates migration. Environmental and endogenous timing mechanisms were analyzed. The results indicate that endogenous stimuli are dominant factors for bird migration especially for long distances. It was concluded that environmental factors act as an assist mechanism.

  13. Epigenetic Upregulation of Endogenous VEGF-A Reduces Myocardial Infarct Size in Mice

    PubMed Central

    Musthafa, Haja; Laidinen, Svetlana; Dragneva, Galina; Laham-Karam, Nihay; Honkanen, Sanna; Paakinaho, Anne; Laakkonen, Johanna P.; Gao, Erhe; Vihinen-Ranta, Maija; Liimatainen, Timo; Ylä-Herttuala, Seppo

    2014-01-01

    “Epigenetherapy” alters epigenetic status of the targeted chromatin and modifies expression of the endogenous therapeutic gene. In this study we used lentiviral in vivo delivery of small hairpin RNA (shRNA) into hearts in a murine infarction model. shRNA complementary to the promoter of vascular endothelial growth factor (VEGF-A) was able to upregulate endogenous VEGF-A expression. Histological and multiphoton microscope analysis confirmed the therapeutic effect in the transduced hearts. Magnetic resonance imaging (MRI) showed in vivo that the infarct size was significantly reduced in the treatment group 14 days after the epigenetherapy. Importantly, we show that promoter-targeted shRNA upregulates all isoforms of endogenous VEGF-A and that an intact hairpin structure is required for the shRNA activity. In conclusion, regulation of gene expression at the promoter level is a promising new treatment strategy for myocardial infarction and also potentially useful for the upregulation of other endogenous genes. PMID:24587164

  14. Atomic resolution structure of Moloney murine leukemia virus matrix protein and its relationship to other retroviral matrix proteins.

    PubMed

    Riffel, Nico; Harlos, Karl; Iourin, Oleg; Rao, Zihe; Kingsman, Alan; Stuart, David; Fry, Elizabeth

    2002-12-01

    Matrix proteins associated with the viral membrane are important in the formation of the viral particle and in virus maturation. The 1.0 A crystal structure of the ecotropic Gammaretrovirus Moloney murine leukemia virus (M-MuLV) matrix protein reveals the conserved topology of other retroviral matrix proteins, despite undetectable sequence similarity. The N terminus (normally myristylated) is exposed and adjacent to a basic surface patch, features likely to contribute to membrane binding. The four proteins in the asymmetric unit make varied contacts. The M-MuLV matrix structure is intermediate, between those of the lentiviruses and other retroviruses. The protein fold appears to be maintained, in part, by the conservation of side chain packing, which may provide a useful tool for searching for weak distant similarities in proteins. PMID:12467570

  15. Leukemia induction by a new strain of Friend mink cell focus-inducing virus: synergistic effect of Friend ecotropic murine leukemia virus.

    PubMed Central

    Chesebro, B; Wehrly, K; Nishio, J; Evans, L

    1984-01-01

    A new strain of Friend recombinant mink cell focus-inducing retrovirus, FMCF -1-E, was found to induce leukemias in NFS and IRW mice. Although the isolate was obtained from a stock of FMCF -1 ( Troxler et al., J. Exp. Med. 148:639-653, 1978), FMCF -1-E was distinguishable from FMCF -1 by oligonucleotide fingerprinting and antigenic analysis, using monoclonal antibodies. These analyses suggested that FMCF -1-E is a distinct FMCF isolate rather than a simple variant of FMCF -1. After neonatal inoculation, the latency for leukemia induction was 3 to 8 months. A similar long latency was also seen when Friend murine leukemia virus 57 was inoculated into adult (6-week-old) IRW mice. However, sequential inoculation of FMCF -1-E at birth followed by Friend murine leukemia 57 at 6 weeks of age led to a shortened latency period (2.5 to 4 months). Only neonatal inoculation of Friend murine leukemia virus 57 was able to induce a more rapid appearance of leukemia. The leukemia cell type in the majority of cases, regardless of virus inoculation protocol, was erythroid, but occasional myeloid, lymphoid, and mixed leukemias were also observed. In contrast to NFS and IRW mice, BALB/c mice were resistant to leukemia induction by FMCF -1-E and also showed some transient resistance to leukemia induction by Friend murine leukemia virus 57. Images PMID:6202886

  16. Serum Antibody Response to Koala Retrovirus Antigens Varies in Free-Ranging Koalas ( Phascolarctos cinereus ) in Australia: Implications for Vaccine Design.

    PubMed

    Waugh, Courtney; Gillett, Amber; Polkinghorne, Adam; Timms, Peter

    2016-04-28

    Little is known about the immune response in the koala ( Phascolarctos cinereus ) to its retroviruses. Koala retroviruses (KoRVs) have been linked to neoplasia in wild and captive koalas, but there is no treatment available. We tested the KoRV-specific serum immunoglobulin G antibody response in nonimmunized and immunized koalas. PMID:27054470

  17. Antimicrobial proteins of murine macrophages.

    PubMed Central

    Hiemstra, P S; Eisenhauer, P B; Harwig, S S; van den Barselaar, M T; van Furth, R; Lehrer, R I

    1993-01-01

    Three murine microbicidal proteins (MUMPs) were purified from cells of the murine macrophage cell line RAW264.7 that had been activated by gamma interferon. Similar proteins were also present in nonactivated RAW264.7 cells, in cells of the murine macrophage cell line J774A.1, and in resident and activated murine peritoneal macrophages. MUMP-1, MUMP-2, and MUMP-3 killed Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Mycobacterium fortuitum, and Cryptococcus neoformans in vitro. MUMP-1 resembled an H1 histone but was unusual because its N-terminal residue (serine) was not N acetylated. Although MUMP-2 was N terminally blocked, its high lysine/arginine ratio and its reactivity with an antibody to H1 histones suggested that it also belonged to the H1 histone family. MUMP-3 was identical to histone H2B in 30 of 30 amino-terminal residues. Although the antimicrobial properties of histones have been recognized for decades, this is the first evidence that such proteins may endow the lysosomal apparatus of macrophages with nonoxidative antimicrobial potential. Other MUMPs, including some with a more restricted antimicrobial spectrum and one that appeared to be induced in RAW264.7 cells after gamma interferon stimulation, were noted but remain to be characterized. Images PMID:8514411

  18. [Microspectrofluorometric analysis of the effect of centrophenoxine on lipofuscin granules of hybridoma (Retrovirus-transformed) cells].

    PubMed

    Tatariunas, A B

    1990-04-01

    The increase of the own luminescence lipofuscin granules (LG) in the course of single and repeated ultraviolet (UV) excitations (365 nm) in hybridoma (retrovirus transformed) cells cultured with or without 5 x 10(-4) M centrophenoxine (CP) was studied by microspectrofluorometric method. It was shown that CP influences only the rate of photochemical changes of chromophores in LG. Kinetic patterns of the own luminescence intensity of LG at the wavelength of 540 nm during excitation by UV permit one to suggest the occurrence of the cyclic chromophore changes. PMID:2117472

  19. Specific in vivo labeling with GFP retroviruses, lentiviruses, and adenoviruses for imaging

    NASA Astrophysics Data System (ADS)

    Hoffman, Robert M.; Kishimoto, Hiroyuki; Fujiwara, Toshiyoshi

    2008-02-01

    Fluorescent proteins have revolutionized the field of imaging. Our laboratory pioneered in vivo imaging with fluorescent proteins. Fluorescent proteins have enabled imaging at the subcellular level in mice. We review here the use of different vectors carrying fluorescent proteins to selectively label normal and tumor tissue in vivo. We show that a GFP retrovirus and telomerase-driven GFP adenovirus can selectively label tumors in mice. We also show that a GFP lentivirus can selectively label the liver in mice. The practical application of these results are discussed.

  20. Evolution of functional and sequence variants of the mammalian XPR1 receptor for mouse xenotropic gammaretroviruses and the human-derived retrovirus XMRV.

    PubMed

    Yan, Yuhe; Liu, Qingping; Wollenberg, Kurt; Martin, Carrie; Buckler-White, Alicia; Kozak, Christine A

    2010-11-01

    Genetic conflicts between retroviruses and their receptors result in the evolution of novel host entry restrictions and novel virus envelopes, and such variants can influence trans-species transmission. We screened rodents and other mammals for sequence variation in the Xpr1 receptor for the mouse xenotropic or polytropic mouse leukemia viruses (X-MLVs or P-MLVs, respectively) of the gammaretrovirus family and for susceptibility to mouse-derived X/P-MLVs and to XMRV (xenotropic murine leukemia virus-related virus), an X-MLV-like virus isolated from humans with prostate cancer and chronic fatigue syndrome. We identified multiple distinct susceptibility phenotypes; these include the four known Xpr1 variants in Mus and a novel fifth Xpr1 gene found in Mus molossinus and Mus musculus. We describe the geographic and species distribution of the Mus Xpr1 variants but failed to find the X-MLV-restrictive laboratory mouse allele in any wild mouse. We used mutagenesis and phylogenetic analysis to evaluate the functional contributions made by constrained, variable, and deleted residues. Rodent Xpr1 is under positive selection, indicating a history of host-pathogen conflicts; several codons under selection have known roles in virus entry. All non-Mus mammals are susceptible to mouse X-MLVs, but some restrict other members of the X/P-MLV family, and the resistance of hamster and gerbil cells to XMRV indicates that XMRV has unique receptor requirements. We show that the hypervariable fourth extracellular XPR1 loop (ECL4) contains three evolutionarily constrained residues that do not contribute to receptor function, we identify two novel residues important for virus entry (I579 and T583), and we describe a unique pattern of ECL4 variation in the three virus-restrictive Xpr1 variants found in MLV-infected house mice; these mice carry different deletions in ECL4, suggesting either that these sites or loop size affects receptor function. PMID:20844050

  1. Gravity effects on endogenous movements

    NASA Astrophysics Data System (ADS)

    Johnsson, Anders; Antonsen, Frank

    Gravity effects on endogenous movements A. Johnsson * and F. Antonsen *+ * Department of Physics, Norwegian University of Science and Technology,NO-7491, Trond-heim, Norway, E-mail: anders.johnsson@ntnu.no + Present address: Statoil Research Center Trondheim, NO-7005, Trondheim, Norway Circumnutations in stems/shoots exist in many plants and often consists of more or less regular helical movements around the plumb line under Earth conditions. Recent results on circumnu-tations of Arabidopsis in space (Johnsson et al. 2009) showed that minute amplitude oscilla-tions exist in weightlessness, but that centripetal acceleration (mimicking the gravity) amplified and/or created large amplitude oscillations. Fundamental mechanisms underlying these results will be discussed by modeling the plant tissue as a cylinder of cells coupled together. As a starting point we have modeled (Antonsen 1998) standing waves on a ring of biological cells, as first discussed in a classical paper (Turing 1952). If the coupled cells can change their water content, an `extension' wave could move around the ring. We have studied several, stacked rings of cells coupled into a cylinder that together represent a cylindrical plant tissue. Waves of extensions travelling around the cylinder could then represent the observable circumnutations. The coupling between cells can be due to cell-to-cell diffusion, or to transport via channels, and the coupling can be modeled to vary in both longitudinal and transversal direction of the cylinder. The results from ISS experiments indicate that this cylindrical model of coupled cells should be able to 1) show self-sustained oscillations without the impact of gravity (being en-dogenous) and 2) show how an environmental factor like gravity can amplify or generate the oscillatory movements. Gravity has been introduced in the model by a negative, time-delayed feed-back transport across the cylinder. This represents the physiological reactions to acceler

  2. Enhanced transformation by a simian virus 40 recombinant virus containing a Harvey murine sarcoma virus long terminal repeat.

    PubMed Central

    Kriegler, M; Botchan, M

    1983-01-01

    We have constructed a recombinant simian virus 40 (SV40) DNA containing a copy of the Harvey murine sarcoma virus long terminal repeat (LTR). This recombinant viral DNA was converted into an infectious SV40 virus particle and subsequently infected into NIH 3T3 cells (either uninfected or previously infected with Moloney leukemia virus). We found that this hybrid virus, SVLTR1, transforms cells with 10 to 20 times the efficiency of SV40 wild type. Southern blot analysis of these transformed cell genomic DNAs revealed that simple integration of the viral DNA within the retrovirus LTR cannot account for the enhanced transformation of the recombinant virus. A restriction fragment derived from the SVLTR-1 virus which contains an intact LTR was readily identified in a majority of the transformed cell DNAs. These results suggest that the LTR fragment which contains the attachment sites and flanking sequences for the proviral DNA duplex may be insufficient by itself to facilitate correct retrovirus integration and that some other functional element of the LTR is responsible for the increased transformation potential of this virus. We have found that a complete copy of the Harvey murine sarcoma virus LTR linked to well-defined structural genes lacking their own promoters (SV40 early region, thymidine kinase, and G418 resistance) can be effectively used to promote marker gene expression. To determine which element of the LTR served to enhance the biological activity of the recombinant virus described above, we deleted DNA sequences essential for promoter activity within the LTR. SV40 virus stocks reconstructed with this mutated copy of the Harvey murine sarcoma virus LTR still transform mouse cells at an enhanced frequency. We speculate that when the LTR is placed more than 1.5 kilobases from the SV40 early promoter, the cis-acting enhancer element within the LTR can increase the ability of the SV40 promoter to effectively operate when integrated in a murine chromosome

  3. Selenium suppresses leukemia through the action of endogenous eicosanoids.

    PubMed

    Gandhi, Ujjawal H; Kaushal, Naveen; Hegde, Shailaja; Finch, Emily R; Kudva, Avinash K; Kennett, Mary J; Jordan, Craig T; Paulson, Robert F; Prabhu, K Sandeep

    2014-07-15

    Eradicating cancer stem-like cells (CSC) may be essential to fully eradicate cancer. Metabolic changes in CSC could hold a key to their targeting. Here, we report that the dietary micronutrient selenium can trigger apoptosis of CSC derived from chronic or acute myelogenous leukemias when administered at supraphysiologic but nontoxic doses. In leukemia CSC, selenium treatment activated ATM-p53-dependent apoptosis accompanied by increased intracellular levels of reactive oxygen species. Importantly, the same treatment did not trigger apoptosis in hematopoietic stem cells. Serial transplantation studies with BCR-ABL-expressing CSC revealed that the selenium status in mice was a key determinant of CSC survival. Selenium action relied upon the endogenous production of the cyclooxygenase-derived prostaglandins Δ(12)-PGJ2 and 15d-PGJ2. Accordingly, nonsteroidal anti-inflammatory drugs and NADPH oxidase inhibitors abrogated the ability of selenium to trigger apoptosis in leukemia CSC. Our results reveal how selenium-dependent modulation of arachidonic acid metabolism can be directed to trigger apoptosis of primary human and murine CSC in leukemia. PMID:24872387

  4. Accelerated Human Mutant Tau Aggregation by Knocking Out Murine Tau in a Transgenic Mouse Model

    PubMed Central

    Ando, Kunie; Leroy, Karelle; Héraud, Céline; Yilmaz, Zehra; Authelet, Michèle; Suain, Valèrie; De Decker, Robert; Brion, Jean-Pierre

    2011-01-01

    Many models of human tauopathies have been generated in mice by expression of a human mutant tau with maintained expression of mouse endogenous tau. Because murine tau might interfere with the toxic effects of human mutant tau, we generated a model in which a pathogenic human tau protein is expressed in the absence of wild-type tau protein, with the aim of facilitating the study of the pathogenic role of the mutant tau and to reproduce more faithfully a human tauopathy. The Tg30 line is a tau transgenic mouse model overexpressing human 1N4R double-mutant tau (P301S and G272V) that develops Alzheimer's disease-like neurofibrillary tangles in an age-dependent manner. By crossing Tg30 mice with mice invalidated for their endogenous tau gene, we obtained Tg30xtau−/− mice that express only exogenous human double-mutant 1N4R tau. Although Tg30xtau−/− mice express less tau protein compared with Tg30, they exhibit signs of decreased survival, increased proportion of sarkosyl-insoluble tau in the brain and in the spinal cord, increased number of Gallyas-positive neurofibrillary tangles in the hippocampus, increased number of inclusions in the spinal cord, and a more severe motor phenotype. Deletion of murine tau accelerated tau aggregation during aging of this mutant tau transgenic model, suggesting that murine tau could interfere with the development of tau pathology in transgenic models of human tauopathies. PMID:21281813

  5. Induction of murine p30 by superinfecting herpesviruses.

    PubMed Central

    Reed, C L; Rapp, F

    1976-01-01

    The interaction of endogenous type C viruses with superinfecting herpes simplex virus type 2 (HSV-2) was investigated in two murine cell lines. Replication of HSV-2 was suboptimal in random-bred Swiss/3T3A cells and, in initial experiments, infection with a low virus-to-cell ratio resulted in carrier cultures with enhanced murine leukemia virus (MuLV) p30 expression. Immunofluorescence tests with Swiss/3T3A cells productively infected with HSV-2 also showed HSV-associated cytoplasmic antigens and enhanced MuLV p30 expression when compared with uninfected controls. Inactivation of HSV-2 with UV light did not abolish this reaction, although the number of cells expressing p30 was reduced. HSV-2 replicated more efficiently in a line of NIH Swiss cells (N c1 A c1 10). These cells are not readily inducible for type C expression by conventional methods; however, untreated and UV-inactivated HSV-2 induced both HSV-2-associated antigens and MuLV p30 in these cells. Although the Birch strain of human cytomegalovirus induced MuLV p30, neither mouse cytomegalovirus nor vesicular stomatitis virus induced MuLV p30 in either cell line. Images PMID:184296

  6. Retrovirus-mediated conditional immortalization and analysis of established cell lines of osteoclast precursor cells

    SciTech Connect

    Kawata, Shigehisa; Suzuki, Jun; Maruoka, Masahiro; Mizutamari, Megumi; Ishida-Kitagawa, Norihiro; Yogo, Keiichiro; Jat, Parmjit S.; Shishido, Tomoyuki . E-mail: shishid@bs.naist.jp

    2006-11-10

    Osteoclast precursor cells (OPCs) have previously been established from bone marrow cells of SV40 temperature-sensitive T antigen-expressing transgenic mice. Here, we use retrovirus-mediated gene transfer to conditionally immortalize OPCs by expressing temperature-sensitive large T antigen (tsLT) from wild type bone marrow cells. The immortalized OPCs proliferated at the permissive temperature of 33.5 deg. C, but stopped growing at the non-permissive temperature of 39 deg. C. In the presence of receptor activator of NF{kappa}B ligand (RANKL), the OPCs differentiated into tartrate-resistant acid phosphatase (TRAP)-positive cells and formed multinucleate osteoclasts at 33.5 deg. C. From these OPCs, we cloned two types of cell lines. Both differentiated into TRAP-positive cells, but one formed multinucleate osteoclasts while the other remained unfused in the presence of RANKL. These results indicate that the established cell lines are useful for analyzing mechanisms of differentiation, particularly multinucleate osteoclast formation. Retrovirus-mediated conditional immortalization should be a useful method to immortalize OPCs from primary bone marrow cells.

  7. Messenger RNA- Versus Retrovirus-Based Induced Pluripotent Stem Cell Reprogramming Strategies: Analysis of Genomic Integrity

    PubMed Central

    Steichen, Clara; Luce, Eléanor; Maluenda, Jérôme; Tosca, Lucie; Moreno-Gimeno, Inmaculada; Desterke, Christophe; Dianat, Noushin; Goulinet-Mainot, Sylvie; Awan-Toor, Sarah; Burks, Deborah; Marie, Joëlle; Weber, Anne; Tachdjian, Gérard; Melki, Judith

    2014-01-01

    The use of synthetic messenger RNAs to generate human induced pluripotent stem cells (iPSCs) is particularly appealing for potential regenerative medicine applications, because it overcomes the common drawbacks of DNA-based or virus-based reprogramming strategies, including transgene integration in particular. We compared the genomic integrity of mRNA-derived iPSCs with that of retrovirus-derived iPSCs generated in strictly comparable conditions, by single-nucleotide polymorphism (SNP) and copy number variation (CNV) analyses. We showed that mRNA-derived iPSCs do not differ significantly from the parental fibroblasts in SNP analysis, whereas retrovirus-derived iPSCs do. We found that the number of CNVs seemed independent of the reprogramming method, instead appearing to be clone-dependent. Furthermore, differentiation studies indicated that mRNA-derived iPSCs differentiated efficiently into hepatoblasts and that these cells did not load additional CNVs during differentiation. The integration-free hepatoblasts that were generated constitute a new tool for the study of diseased hepatocytes derived from patients’ iPSCs and their use in the context of stem cell-derived hepatocyte transplantation. Our findings also highlight the need to conduct careful studies on genome integrity for the selection of iPSC lines before using them for further applications. PMID:24736403

  8. Hybridization Capture Reveals Evolution and Conservation across the Entire Koala Retrovirus Genome

    PubMed Central

    Ishida, Yasuko; Cui, Pin; Vielgrader, Hanna; Helgen, Kristofer M.; Roca, Alfred L.; Greenwood, Alex D.

    2014-01-01

    The koala retrovirus (KoRV) is the only retrovirus known to be in the midst of invading the germ line of its host species. Hybridization capture and next generation sequencing were used on modern and museum DNA samples of koala (Phascolarctos cinereus) to examine ca. 130 years of evolution across the full KoRV genome. Overall, the entire proviral genome appeared to be conserved across time in sequence, protein structure and transcriptional binding sites. A total of 138 polymorphisms were detected, of which 72 were found in more than one individual. At every polymorphic site in the museum koalas, one of the character states matched that of modern KoRV. Among non-synonymous polymorphisms, radical substitutions involving large physiochemical differences between amino acids were elevated in env, potentially reflecting anti-viral immune pressure or avoidance of receptor interference. Polymorphisms were not detected within two functional regions believed to affect infectivity. Host sequences flanking proviral integration sites were also captured; with few proviral loci shared among koalas. Recently described variants of KoRV, designated KoRV-B and KoRV-J, were not detected in museum samples, suggesting that these variants may be of recent origin. PMID:24752422

  9. Endoplasmic Reticulum Stress Is a Determinant of Retrovirus-Induced Spongiform Neurodegeneration

    PubMed Central

    Dimcheff, Derek E.; Askovic, Srdjan; Baker, Audrey H.; Johnson-Fowler, Cedar; Portis, John L.

    2003-01-01

    FrCasE is a mouse retrovirus that causes a fatal noninflammatory spongiform neurodegenerative disease with pathological features strikingly similar to those induced by transmissible spongiform encephalopathy (TSE) agents. Neurovirulence is determined by the sequence of the viral envelope protein, though the specific role of this protein in disease pathogenesis is not known. In the present study, we compared host gene expression in the brain stems of mice infected with either FrCasE or the avirulent virus F43, differing from FrCasE in the sequence of the envelope gene. Four of the 12 disease-specific transcripts up-regulated during the preclinical period represent responses linked to the accumulation of unfolded proteins in the endoplasmic reticulum (ER). Among these genes was CHOP/GADD153, which is induced in response to conditions that perturb endoplasmic reticulum function. In vitro studies with NIH 3T3 cells revealed up-regulation of CHOP as well as BiP, calreticulin, and Grp58/ERp57 in cells infected with FrCasE but not with F43. Immunoblot analysis of infected NIH 3T3 cells demonstrated the accumulation of uncleaved envelope precursor protein in FrCasE- but not F43-infected cells, consistent with ER retention. These results suggest that retrovirus-induced spongiform neurodegeneration represents a protein-folding disease and thus may provide a useful tool for exploring the causal link between protein misfolding and the cytopathology that it causes. PMID:14610184

  10. New bioinformatic tool for quick identification of functionally relevant endogenous retroviral inserts in human genome

    PubMed Central

    Garazha, Andrew; Ivanova, Alena; Suntsova, Maria; Malakhova, Galina; Roumiantsev, Sergey; Zhavoronkov, Alex; Buzdin, Anton

    2015-01-01

    Abstract Endogenous retroviruses (ERVs) and LTR retrotransposons (LRs) occupy ∼8% of human genome. Deep sequencing technologies provide clues to understanding of functional relevance of individual ERVs/LRs by enabling direct identification of transcription factor binding sites (TFBS) and other landmarks of functional genomic elements. Here, we performed the genome-wide identification of human ERVs/LRs containing TFBS according to the ENCODE project. We created the first interactive ERV/LRs database that groups the individual inserts according to their familial nomenclature, number of mapped TFBS and divergence from their consensus sequence. Information on any particular element can be easily extracted by the user. We also created a genome browser tool, which enables quick mapping of any ERV/LR insert according to genomic coordinates, known human genes and TFBS. These tools can be used to easily explore functionally relevant individual ERV/LRs, and for studying their impact on the regulation of human genes. Overall, we identified ∼110,000 ERV/LR genomic elements having TFBS. We propose a hypothesis of “domestication” of ERV/LR TFBS by the genome milieu including subsequent stages of initial epigenetic repression, partial functional release, and further mutation-driven reshaping of TFBS in tight coevolution with the enclosing genomic loci. PMID:25853282

  11. New bioinformatic tool for quick identification of functionally relevant endogenous retroviral inserts in human genome.

    PubMed

    Garazha, Andrew; Ivanova, Alena; Suntsova, Maria; Malakhova, Galina; Roumiantsev, Sergey; Zhavoronkov, Alex; Buzdin, Anton

    2015-01-01

    Endogenous retroviruses (ERVs) and LTR retrotransposons (LRs) occupy ∼8% of human genome. Deep sequencing technologies provide clues to understanding of functional relevance of individual ERVs/LRs by enabling direct identification of transcription factor binding sites (TFBS) and other landmarks of functional genomic elements. Here, we performed the genome-wide identification of human ERVs/LRs containing TFBS according to the ENCODE project. We created the first interactive ERV/LRs database that groups the individual inserts according to their familial nomenclature, number of mapped TFBS and divergence from their consensus sequence. Information on any particular element can be easily extracted by the user. We also created a genome browser tool, which enables quick mapping of any ERV/LR insert according to genomic coordinates, known human genes and TFBS. These tools can be used to easily explore functionally relevant individual ERV/LRs, and for studying their impact on the regulation of human genes. Overall, we identified ∼110,000 ERV/LR genomic elements having TFBS. We propose a hypothesis of "domestication" of ERV/LR TFBS by the genome milieu including subsequent stages of initial epigenetic repression, partial functional release, and further mutation-driven reshaping of TFBS in tight coevolution with the enclosing genomic loci. PMID:25853282

  12. Mechanism of endogenous myc gene down-regulation in E mu-N-myc tumors.

    PubMed

    Ma, A; Smith, R K; Tesfaye, A; Achacoso, P; Dildrop, R; Rosenberg, N; Alt, F W

    1991-01-01

    Transgenic mouse lines carrying the N-myc oncogene deregulated by the immunoglobulin heavy-chain enhancer spontaneously develop B-lymphoid tumors (R. Dildrop, A. Ma, K. Zimmerman, E. Hsu, A. Tesfaye, R. DePinho, and F. W. Alt, EMBO J. 8:1121-1128, 1989; H. Rosenbaum, E. Webb, J. M. Adams, S. Cory, and A. W. Harris, EMBO J. 8:749-755). Permanent cell lines derived from these tumors (E mu-N-myc cell lines) express extremely high levels of the N-myc transgene but little or no detectable endogenous N-myc or c-myc. We have employed nuclear run-on assays to show that down-regulation of endogenous N- and c-myc expression occurs at the transcriptional level. To determine whether the lack of endogenous myc gene transcription is a direct effect of high-level N-myc transgene expression, we have generated Abelson murine leukemia virus (A-MuLV)-transformed cell lines from prelymphomatous E mu-N-myc mice (A-MuLV/E mu-N-myc cell lines). Although these A-MuLV/E mu-N-myc lines express very high levels of the N-myc transgene, they continue to transcribe the endogenous c-myc gene. These findings demonstrate that high-level N-myc gene expression alone does not necessarily lead to down-regulation of endogenous myc gene expression and suggest that events associated with transformation by N-myc may be critical to this process. PMID:1986238

  13. Trim33 Binds and Silences a Class of Young Endogenous Retroviruses in the Mouse Testis; a Novel Component of the Arms Race between Retrotransposons and the Host Genome

    PubMed Central

    Isbel, Luke; Srivastava, Rahul; Oey, Harald; Spurling, Alex; Daxinger, Lucia; Puthalakath, Hamsa; Whitelaw, Emma

    2015-01-01

    Transposable elements (TEs) have been active in the mammalian genome for millions of years and the silencing of these elements in the germline is important for the survival of the host. Mice carrying reporter transgenes can be used to model transcriptional silencing. A mutagenesis screen for modifiers of epigenetic gene silencing produced a line with a mutation in Trim33; the mutants displayed increased expression of the reporter transgene. ChIP-seq of Trim33 in testis revealed 9,109 peaks, mostly at promoters. This is the first report of ChIP-seq for Trim33 in any tissue. Comparison with ENCODE datasets showed that regions of high read density for Trim33 had high read density for histone marks associated with transcriptional activity and mapping to TE consensus sequences revealed Trim33 enrichment at RLTR10B, the LTR of one of the youngest retrotransposons in the mouse genome, MMERVK10C. We identified consensus sequences from the 266 regions at which Trim33 ChIP-seq peaks overlapped RLTR10B elements and found a match to the A-Myb DNA-binding site. We found that TRIM33 has E3 ubiquitin ligase activity for A-MYB and regulates its abundance. RNA-seq revealed that mice haploinsufficient for Trim33 had altered expression of a small group of genes in the testis and the gene with the most significant increase was found to be transcribed from an upstream RLTR10B. These studies provide the first evidence that A-Myb has a role in the actions of Trim33 and suggest a role for both A-Myb and Trim33 in the arms race between the transposon and the host. This the first report of any factor specifically regulating RLTR10B and adds to the current literature on the silencing of MMERVK10C retrotransposons. This is also the first report that A-Myb has a role in the transcription of any retrotransposon. PMID:26624618

  14. Trim33 Binds and Silences a Class of Young Endogenous Retroviruses in the Mouse Testis; a Novel Component of the Arms Race between Retrotransposons and the Host Genome.

    PubMed

    Isbel, Luke; Srivastava, Rahul; Oey, Harald; Spurling, Alex; Daxinger, Lucia; Puthalakath, Hamsa; Whitelaw, Emma

    2015-12-01

    Transposable elements (TEs) have been active in the mammalian genome for millions of years and the silencing of these elements in the germline is important for the survival of the host. Mice carrying reporter transgenes can be used to model transcriptional silencing. A mutagenesis screen for modifiers of epigenetic gene silencing produced a line with a mutation in Trim33; the mutants displayed increased expression of the reporter transgene. ChIP-seq of Trim33 in testis revealed 9,109 peaks, mostly at promoters. This is the first report of ChIP-seq for Trim33 in any tissue. Comparison with ENCODE datasets showed that regions of high read density for Trim33 had high read density for histone marks associated with transcriptional activity and mapping to TE consensus sequences revealed Trim33 enrichment at RLTR10B, the LTR of one of the youngest retrotransposons in the mouse genome, MMERVK10C. We identified consensus sequences from the 266 regions at which Trim33 ChIP-seq peaks overlapped RLTR10B elements and found a match to the A-Myb DNA-binding site. We found that TRIM33 has E3 ubiquitin ligase activity for A-MYB and regulates its abundance. RNA-seq revealed that mice haploinsufficient for Trim33 had altered expression of a small group of genes in the testis and the gene with the most significant increase was found to be transcribed from an upstream RLTR10B. These studies provide the first evidence that A-Myb has a role in the actions of Trim33 and suggest a role for both A-Myb and Trim33 in the arms race between the transposon and the host. This the first report of any factor specifically regulating RLTR10B and adds to the current literature on the silencing of MMERVK10C retrotransposons. This is also the first report that A-Myb has a role in the transcription of any retrotransposon. PMID:26624618

  15. Commensal bacteria drive endogenous transformation and tumour stem cell marker expression through a bystander effect

    PubMed Central

    Wang, Xingmin; Yang, Yonghong; Huycke, Mark M

    2015-01-01

    Objective Commensal bacteria and innate immunity play a major role in the development of colorectal cancer (CRC). We propose that selected commensals polarise colon macrophages to produce endogenous mutagens that initiate chromosomal instability (CIN), lead to expression of progenitor and tumour stem cell markers, and drive CRC through a bystander effect. Design Primary murine colon epithelial cells were repetitively exposed to Enterococcus faecalis-infected macrophages, or purified trans-4-hydroxy-2-nonenal (4-HNE)—an endogenous mutagen and spindle poison produced by macrophages. CIN, gene expression, growth as allografts in immunodeficient mice were examined for clones and expression of markers confirmed using interleukin (IL) 10 knockout mice colonised by E. faecalis. Results Primary colon epithelial cells exposed to polarised macrophages or 4-hydroxy-2-nonenal developed CIN and were transformed after 10 weekly treatments. In immunodeficient mice, 8 of 25 transformed clones grew as poorly differentiated carcinomas with 3 tumours invading skin and/or muscle. All tumours stained for cytokeratins confirming their epithelial cell origin. Gene expression profiling of clones showed alterations in 3 to 7 cancer driver genes per clone. Clones also strongly expressed stem/progenitor cell markers Ly6A and Ly6E. Although not differentially expressed in clones, murine allografts positively stained for the tumour stem cell marker doublecortin-like kinase 1. Doublecortin-like kinase 1 and Ly6A/E were expressed by epithelial cells in colon biopsies for areas of inflamed and dysplastic tissue from E. faecalis-colonised IL-10 knockout mice. Conclusions These results validate a novel mechanism for CRC that involves endogenous CIN and cellular transformation arising through a microbiome-driven bystander effect. PMID:24906974

  16. Endogenous Optical Signals Reveal Changes of Elastin and Collagen Organization During Differentiation of Mouse Embryonic Stem Cells.

    PubMed

    Thimm, Terra N; Squirrell, Jayne M; Liu, Yuming; Eliceiri, Kevin W; Ogle, Brenda M

    2015-10-01

    Components of the extracellular matrix (ECM) have recently been shown to influence stem cell specification. However, it has been challenging to assess the spatial and temporal dynamics of stem cell-ECM interactions because most methodologies utilized to date require sample destruction or fixation. We examined the efficacy of utilizing the endogenous optical signals of two important ECM proteins, elastin (Eln), through autofluorescence, and type I collagen (ColI), through second harmonic generation (SHG), during mouse embryonic stem cell differentiation. After finding favorable overlap between antibody labeling and the endogenous fluorescent signal of Eln, we used this endogenous signal to map temporal changes in Eln and ColI during murine embryoid body differentiation and found that Eln increases until day 9 and then decreases slightly by day 12, while Col1 steadily increases over the 12-day period. Furthermore, we combined endogenous fluorescence imaging and SHG with antibody labeling of cardiomyocytes to examine the spatial relationship between Eln and ColI accumulation and cardiomyocyte differentiation. Eln was ubiquitously present, with enrichment in regions with cardiomyocyte differentiation, while there was an inverse correlation between ColI and cardiomyocyte differentiation. This work provides an important first step for utilizing endogenous optical signals, which can be visualized in living cells, to understand the relationship between the ECM and cardiomyocyte development and sets the stage for future studies of stem cell-ECM interactions and dynamics relevant to stem cells as well as other cell and tissue types. PMID:25923353

  17. Rat sequences of the Kirsten and Harvey murine sarcoma virus genomes: nature, origin, and expression in rat tumor RNA.

    PubMed Central

    Anderson, G R; Robbins, K C

    1976-01-01

    Two murine sarcoma viruses, the Kirsten and the Harvey, were isolated by passage of mouse type C leukemia viruses through rats. These sarcoma viruses have genomes containing portions of their parental type C mouse leukemia virus genomes, in stable association with specific rat cellular sequences that we find to be quite likely not those of a rat type C leukemia virus. To determine if these murine sarcoma viruses provide a model relevant to the events occurring in spontaneous tumors, we have hybridized DNA and RNA prepared from rat tumors and normal rat tissues to [3H]DNA prepared from the Kirsten murine sarcoma virus. We have also hybridized these rat tissue nucleic acids to [3H]DNA prepared from a respresentative endogenous rat type C leukemia virus, the WFU (Wistar-Furth). Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected in the DNA of both tumor and normal tissues, with no evidence of either gene amplification or additional sequences being present in tumor DNA. Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected at elevated concentrations in the RNA of many rat tumors and in specific groups of normal tissues. PMID:176419

  18. A report from the Conference on Retroviruses and Opportunistic Infections (CROI) 2015 (February 23-26--Seattle, Washington, USA).

    PubMed

    Rabasseda, X

    2015-03-01

    The largest conference on HIV and AIDS, the annual Conference on Retroviruses and Opportunistic Infections (CROI) also encompasses opportunistic and other important pathogens, notably in 2015 hepatitis C virus and the Ebola virus. This year's conference involved 4 days of discussions on highly relevant basic, translational and clinical research and developments in the ongoing battle against these infections. PMID:25876564

  19. Sequence comparison in the crossover region of an oncogenic avian retrovirus recombinant and its nononcogenic parent: Genetic regions that control growth rate and oncogenic potential

    SciTech Connect

    Tsichlis, P.N.; Donehower, L.; Hager, G.; Zeller, N.; Malavarca, R.; Astrin, S.; Skalka, A.M.

    1982-11-01

    NTRE is an avian retrovirus recombinant of the endogeneous nononcogenic Rous-associated virus-0 (RAV-0) and the oncogenic, exogeneous, transformation-defective (td) Prague strain of Rous sarcoma virus B (td-PrRSV-B). Oligonucleotide mapping had shown that the recombinant virus is indistinguishable from its RAV-0 parent except for the 3'-end sequences, which were derived from td-PrRSV-B. However, the virus exhibits properties which are typical of an exogenous virus: it grows to high titers in tissue culture, and it is oncogenic in vivo. To accurately define the genetic region responsible for these properties, the authors determined the nucleotide sequences of the recombinant and its RAV-0 parent by using molecular clones of their DNA. These were compared with sequences already available for PrRSV-C, a virus closely related to the exogenous parent td-PrRSV-B. The results suggested that the crossover event which generated NTRE 7 took place in a region -501 to -401 nucleotides from the 3' end of the td-PrRSV parental genome and that sequences to the right of the recombination region were responsible for its growth properties and oncogenic potential. Since the exogenous-virus-specific sequences are expected to be missing from transformation-defective mutants of the Schmidt-Ruppin strain of RSV, which, like other exogeneous viruses, grow to high tiers in tissue culture and are oncogenic in vivo, the authors concluded that the growth properties and oncogenic potential of the exogeneous viruses are determined by sequences in the U3 region of the long terminal repeat. However, the authors propose that the exogeneous-virus-specific region may play a role in determining the oncogenic spectrum of a given oncogenic virus.

  20. Full-sized HERV-K (HML-2) human endogenous retroviral LTR sequences on human chromosome 21: map locations and evolutionary history.

    PubMed

    Kurdyukov, S G; Lebedev, Y B; Artamonova, I I; Gorodentseva, T N; Batrak, A V; Mamedov, I Z; Azhikina, T L; Legchilina, S P; Efimenko, I G; Gardiner, K; Sverdlov, E D

    2001-07-25

    One of the evolutionary mechanisms for acquisition of novel functional sequences can be domestication of exogenous retroviruses that have been integrated into the germ line. The whole genome mapping of such elements in various species could reveal differences in positions of the retroviral integration and suggest possible roles of these differences in speciation. Here, we describe the number, locations and sequence features of the human endogenous retrovirus HERV-K (HML-2) long terminal repeat (LTR) sequences on human chromosome 21. We show that their distribution along the chromosome is not only non-random but also roughly correlated with the gene density. Amplification of orthologous LTR sites from a number of primate genomes produced patterns of presence and absence for each LTR sequence and allowed determination of the phylogenetic ages and evolutionary order of appearance of individual LTRs. The identity level and phylogenetic age of the LTRs did not correlate with their map locations. Thus, despite the non-random distribution of LTRs, they have apparently been inserted randomly into the chromosome relative to each other. As evidenced in previous studies of chromosomes 19 and 22, this is a characteristic of HERV-K integration. PMID:11483360

  1. Restrictive flamenco alleles are maintained in Drosophila melanogaster population cages, despite the absence of their endogenous gypsy retroviral targets.

    PubMed

    Pélisson, Alain; Payen-Groschêne, Geneviève; Terzian, Christophe; Bucheton, Alain

    2007-02-01

    The flamenco (flam) locus, located at 20A1-3 in the centromeric heterochromatin of the Drosophila melanogaster X chromosome, is a major regulator of the gypsy/mdg4 endogenous retrovirus. In restrictive strains, functional flam alleles maintain gypsy proviruses in a repressed state. By contrast, in permissive strains, proviral amplification results from infection of the female germ line and subsequent insertions into the chromosomes of the progeny. A restrictive/permissive polymorphism prevails in natural and laboratory populations. This polymorphism was assumed to be maintained by the interplay of opposite selective forces; on one hand, the increase of genetic load caused by proviral insertions would favor restrictive flam alleles because they make flies resistant to these gypsy replicative transpositions and, on the other, a hypothetical resistance cost would select against such alleles in the absence of the retrovirus. However, the population cage data presented in this paper do not fit with this simple resistance cost hypothesis because restrictive alleles were not eliminated in the absence of functional gypsy proviruses; on the contrary, using 2 independent flam allelic pairs, the restrictive frequency rose to about 90% in every experimental population, whatever the pair of alleles and the allelic proportions in the initial inoculum. These data suggest that the flam polymorphism is maintained by some strong balancing selection, which would act either on flam itself, independently of the deleterious effect of gypsy, or on a hypothetical flanking gene, in linkage disequilibrium with flam. Alternatively, restrictive flam alleles might also be resistant to some other retroelements that would be still present in the cage populations, causing a positive selection for these alleles. Whatever selective forces that maintain high levels of restrictive alleles independently of gypsy, this unknown mechanism can set up an interesting kind of antiviral innate immunity, at

  2. Effect of caffeine on induction of endogenous type C virus in mouse cells in vitro

    SciTech Connect

    Niwa, O.; Sugahara, T.

    1981-08-01

    The effect of caffeine on the expression of murine endogenous virus in mouse cells induced by radiation and chemicals was studied. Postirradiation treatment of K-BALB cells with caffeine enhanced cell killing as well as the induction of xenotropic virus after ultraviolet light irradiation. The degree of enhancement for the virus induction was comparable to that for cell killing. On the other hand, colony-forming ability and the expression of xenotropic virus of K-BALB cells after X-irradiation were unaffected by caffeine. These data suggest a linear relationship between the degree of endogenous virus expression and the amount of lethal damages after irradiation. For induction by halogenated pyrimidines, a 24-hr incubation of AKR2B cells with caffeine after 5-iodo-2'-deoxyuridine treatment resulted in marked suppression of the expression of ecotropic virus. On the contrary, in K-BALB cells, caffeine exerted only a small effect on 5-iodo-2'-deoxyuridine-induced expression of ecotropic and xenotropic viruses. These results indicate that, although using the same inducing agent, the pathway of endogenous virus induction may be different for AKR2B cells and for K-BALB cells.

  3. SMADs and FOXL2 synergistically regulate murine FSHbeta transcription via a conserved proximal promoter element.

    PubMed

    Tran, Stella; Lamba, Pankaj; Wang, Ying; Bernard, Daniel J

    2011-07-01

    Pituitary FSH regulates ovarian and testicular function. Activins stimulate FSHβ subunit (Fshb) gene transcription in gonadotrope cells, the rate-limiting step in mature FSH synthesis. Activin A-induced murine Fshb gene transcription in immortalized gonadotropes is dependent on homolog of Drosophila mothers against decapentaplegic (SMAD) proteins as well as the forkhead transcription factor FOXL2 (FOXL2). Here, we demonstrate that FOXL2 synergizes with SMAD2, SMAD3, and SMAD4 to stimulate murine Fshb promoter-reporter activity in heterologous cells. Moreover, SMAD3-induction of Fshb promoter activity or endogenous mRNA expression is dependent upon endogenous FOXL2 in homologous cells. FOXL2/SMAD synergy requires binding of both FOXL2 and SMAD3 or SMAD4 to DNA. Of three putative forkhead-binding elements identified in the murine Fshb promoter, only the most proximal is absolutely required for activin A induction of reporter activity in homologous cells. Additionally, mutations to the minimal SMAD-binding element adjacent to the proximal forkhead-binding element abrogate activin A or FOXL2/SMAD3 induction of reporter activity. In contrast, a mutation that impairs an adjacent PBX1/PREP1 (pre-B cell leukemia transcription factor 1-PBX/knotted-1 homeobox-1) binding site does not alter activin A-stimulated promoter activity in homologous cells. Collectively, these and previous data suggest a model in which activins stimulate formation of FOXL2-SMAD2/3/4 complexes, which bind to the proximal murine Fshb promoter to stimulate its transcription. Within these complexes, FOXL2 and SMAD3 or SMAD4 bind to adjacent cis-elements, with SMAD3 brokering the physical interaction with FOXL2. Because this composite response element is highly conserved, this suggests a general mechanism whereby activins may regulate and/or modulate Fshb transcription in mammals. PMID:21622537

  4. Identification of homeodomain proteins, PBX1 and PREP1, involved in the transcription of murine leukemia virus.

    PubMed

    Chao, Sheng-Hao; Walker, John R; Chanda, Sumit K; Gray, Nathanael S; Caldwell, Jeremy S

    2003-02-01

    Cyclin-dependent kinase inhibitors (CDKIs) have been shown to block human immunodeficiency virus and herpes simplex virus. It is hypothesized that CDKIs block viral replication by inhibiting transcription of specific cellular genes. Here we find that three CDKIs, flavopiridol, purvalanol A, and methoxy-roscovitine, block Moloney murine leukemia virus (MLV) transcription events. Using gene expression microarray technology to examine the inhibitory effects of CDKIs, we observed a cellular gene, the pre-B-cell leukemia transcription factor 1 (Pbx1) gene, down-regulated by CDKI treatment. The PBX consensus element (PCE), TGATTGAC, is conserved in the long terminal repeats of several murine retroviruses, including Moloney MLV. Mutations in the PCE completely inhibited viral transcription whereas overexpression of PBX1 and a PBX1-associated protein, PREP1, enhanced viral transcription. The interaction between the PCE and PBX1-PREP1 proteins was confirmed by gel shift experiments. Blocking PBX1 protein synthesis resulted in a significant decrease in viral transcription. Collectively, our results represent the first work demonstrating that the homeodomain proteins PBX1 and PREP1 are cellular factors involved in Moloney MLV transcription regulation. PMID:12529389

  5. Enhanced proliferation of primary rat type II pneumocytes by Jaagsiekte sheep retrovirus envelope protein

    SciTech Connect

    Johnson, Chassidy; Jahid, Sohail; Voelker, Dennis R.; Fan Hung

    2011-04-10

    Jaagsiekte sheep retrovirus (JSRV) is the causative agent of a contagious lung cancer in sheep. The envelope protein (Env) is the oncogene, as it can transform cell lines in culture and induce tumors in animals, although the mechanisms for transformation are not yet clear because a system to perform transformation assays in differentiated type II pneumocytes does not exist. In this study we report culture of primary rat type II pneumocytes in conditions that favor prolonged expression of markers for type II pneumocytes. Env-expressing cultures formed more colonies that were larger in size and were viable for longer periods of time compared to vector control samples. The cells that remained in culture longer were confirmed to be derived from type II pneumocytes because they expressed surfactant protein C, cytokeratin, displayed alkaline phosphatase activity and were positive for Nile red. This system will be useful to study JSRV Env in the targets of transformation.

  6. Pinpointing retrovirus entry sites in cells expressing alternatively spliced receptor isoforms by single virus imaging

    PubMed Central

    2014-01-01

    Background The majority of viruses enter host cells via endocytosis. Current knowledge of viral entry pathways is largely based upon infectivity measurements following genetic and/or pharmacological interventions that disrupt vesicular trafficking and maturation. Imaging of single virus entry in living cells provides a powerful means to delineate viral trafficking pathways and entry sites under physiological conditions. Results Here, we visualized single avian retrovirus co-trafficking with markers for early (Rab5) and late (Rab7) endosomes, acidification of endosomal lumen and the resulting viral fusion measured by the viral content release into the cytoplasm. Virus-carrying vesicles either merged with the existing Rab5-positive early endosomes or slowly accumulated Rab5. The Rab5 recruitment to virus-carrying endosomes correlated with acidification of their lumen. Viral fusion occurred either in early (Rab5-positive) or intermediate (Rab5- and Rab7-positive) compartments. Interestingly, different isoforms of the cognate receptor directed virus entry from distinct endosomes. In cells expressing the transmembrane receptor, viruses preferentially entered and fused with slowly maturing early endosomes prior to accumulation of Rab7. By comparison, in cells expressing the GPI-anchored receptor, viruses entered both slowly and quickly maturing endosomes and fused with early (Rab5-positive) and intermediate (Rab5- and Rab7-positive) compartments. Conclusions Since the rate of low pH-triggered fusion was independent of the receptor isoform, we concluded that the sites of virus entry are determined by the kinetic competition between endosome maturation and viral fusion. Our findings demonstrate the ability of this retrovirus to enter cells via alternative endocytic pathways and establish infection by releasing its content from distinct endosomal compartments. PMID:24935247

  7. Distribution of a macaque immunosuppressive type D retrovirus in neural, lymphoid, and salivary tissues.

    PubMed Central

    Lackner, A A; Rodriguez, M H; Bush, C E; Munn, R J; Kwang, H S; Moore, P F; Osborn, K G; Marx, P A; Gardner, M B; Lowenstine, L J

    1988-01-01

    Simian acquired immune deficiency syndrome (SAIDS) in rhesus macaques (Macaca mulatta) at the California Primate Research Center is caused by a type D retrovirus designated SAIDS retrovirus serotype 1 (SRV-1). This syndrome is characterized by profound immunosuppression and death associated with opportunistic infections. Neurologic signs and lesions have not been described as part of this syndrome. The distribution of SRV-1 in the salivary glands, lymph nodes, spleens, thymuses, and brains of eight virus-infected rhesus macaques was examined by immunohistochemistry. Electron microscopy, in situ RNA hybridization, and Southern blot hybridization were also performed on selected tissues to detect viral particles, RNA, and DNA, respectively. In seven of eight SRV-1-infected animals, the transmembrane envelope glycoprotein (gp20) of SRV-1 was present in three or more tissues, but never in the brain. In the remaining animal, no viral antigen was detected in any tissue. In this same group of animals, viral nucleic acid was detected in the lymph nodes of six of six animals by Southern blot hybridization, in the salivary glands of two of five animals by both Southern blot and in situ hybridizations, and, surprisingly, in the brains of three of three animals by Southern blot and of three of five animals by in situ hybridization, including the one animal in which viral gp20 was undetectable. None of these animals had neurologic signs or lesions. The detection of viral nucleic acid in the absence of viral antigen in the brain suggests latent SRV-1 infection of the central nervous system. Images PMID:3285033

  8. Vaccination with Irradiated Tumor Cells Engineered to Secrete Murine Granulocyte-Macrophage Colony-Stimulating Factor Stimulates Potent, Specific, and Long-Lasting Anti-Tumor Immunity

    NASA Astrophysics Data System (ADS)

    Dranoff, Glenn; Jaffee, Elizabeth; Lazenby, Audrey; Golumbek, Paul; Levitsky, Hyam; Brose, Katja; Jackson, Valerie; Hamada, Hirofumi; Pardoll, Drew; Mulligan, Richard C.

    1993-04-01

    To compare the ability of different cytokines and other molecules to enhance the immunogenicity of tumor cells, we generated 10 retroviruses encoding potential immunomodulators and studied the vaccination properties of murine tumor cells transduced by the viruses. Using a B16 melanoma model, in which irradiated tumor cells alone do not stimulate significant anti-tumor immunity, we found that irradiated tumor cells expressing murine granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulated potent, long-lasting, and specific anti-tumor immunity, requiring both CD4^+ and CD8^+ cells. Irradiated cells expressing interleukins 4 and 6 also stimulated detectable, but weaker, activity. In contrast to the B16 system, we found that in a number of other tumor models, the levels of anti-tumor immunity reported previously in cytokine gene transfer studies involving live, transduced cells could be achieved through the use of irradiated cells alone. Nevertheless, manipulation of the vaccine or challenge doses made it possible to demonstrate the activity of murine GM-CSF in those systems as well. Overall, our results have important implications for the clinical use of genetically modified tumor cells as therapeutic cancer vaccines.

  9. Tobacco/Nicotine and Endogenous Brain Opioids

    PubMed Central

    Xue, Yue; Domino, Edward F.

    2008-01-01

    Smoking is a major public health problem with devastating health consequences. Although many cigarette smokers are able to quit, equal numbers of others cannot! Standard medications to assist in smoking cessation, such as nicotine replacement therapies and bupropion, are ineffective in many remaining smokers. Recent developments in the neurobiology of nicotine dependence have identified several neurotransmitter systems that may contribute to the process of smoking maintenance and relapse. These include: especially dopamine, but also norepinephrine, 5-hydroxytryptamine, acetylcholine, endogenous opioids, gamma-aminobutyric acid (GABA), glutamate, and endocannabinoids. The present review examines the limited contribution of the endogenous opioid system to the complex effects of nicotine/tobacco smoking. PMID:18215788

  10. An endogenous model of the credit network

    NASA Astrophysics Data System (ADS)

    He, Jianmin; Sui, Xin; Li, Shouwei

    2016-01-01

    In this paper, an endogenous credit network model of firm-bank agents is constructed. The model describes the endogenous formation of firm-firm, firm-bank and bank-bank credit relationships. By means of simulations, the model is capable of showing some obvious similarities with empirical evidence found by other scholars: the upper-tail of firm size distribution can be well fitted with a power-law; the bank size distribution can be lognormally distributed with a power-law tail; the bank in-degrees of the interbank credit network as well as the firm-bank credit network fall into two-power-law distributions.

  11. Animal spirits, competitive markets, and endogenous growth

    NASA Astrophysics Data System (ADS)

    Miyazaki, Kenji

    2013-10-01

    This paper uses a simple model with an endogenous discount rate and linear technology to investigate whether a competitive equilibrium has a higher balanced growth path (BGP) than the social planning solution and whether the BGP is determinate or indeterminate. The implications are as follows. To start with, people with an instinct to compare themselves with others possess an endogenous discount rate. In turn, this instinct affects the economic growth rate in a competitive market economy. The competitive market economy also sometimes achieves higher economic growth than a social planning economy. However, the outcomes of market economy occasionally fluctuate because of the presence of the self-fulfilling prophecy or animal spirits.

  12. The ecology of primate retroviruses – An assessment of 12 years of retroviral studies in the Taï national park area, Côte d'Ivoire

    PubMed Central

    Gogarten, Jan F.; Akoua-Koffi, Chantal; Calvignac-Spencer, Sebastien; Leendertz, Siv Aina J.; Weiss, Sabrina; Couacy-Hymann, Emmanuel; Koné, Inza; Peeters, Martine; Wittig, Roman M.; Boesch, Christophe; Hahn, Beatrice H.; Leendertz, Fabian H.

    2014-01-01

    The existence and genetic make-up of most primate retroviruses was revealed by studies of bushmeat and fecal samples from unhabituated primate communities. For these, detailed data on intra- and within-species contact rates are generally missing, which makes identification of factors influencing transmission a challenging task. Here we present an assessment of 12 years of research on primate retroviruses in the Taï National Park area, Côte d’Ivoire. We discuss insights gained into the prevalence, within- and cross-species transmission of primate retroviruses (including towards local human populations) and the importance of virus–host interactions in determining cross-species transmission risk. Finally we discuss how retroviruses ecology and evolution may change in a shifting environment and identify avenues for future research. PMID:25010280

  13. Molecular approach to human leukemia: Isolation and characterization of the first human retrovirus HTLV-1 and its impact on tumorigenesis in Adult T-cell Leukemia

    PubMed Central

    Yoshida, Mitsuaki

    2010-01-01

    Molecular biology of mouse and chicken retroviruses had identified oncogenes and provided a revolutionary concept in understanding of cancers. A human retrovirus was established during 1980–1982 in linkage with a unique human leukemia, concurrently in Japan and USA. This review covers our efforts on the discovery of new retrovirus, Human T-cell Leukemia Virus Type 1 (HTLV-1), first introducing to a new class of retroviruses with a unique regulatory factors, Tax and Rex. Then it is followed by analyses of molecular interaction of the vial Tax with cellular machineries involved in the pathogenesis of Adult T-cell Leukemia (ATL). And then a probable mechanism of pathogenesis of ATL is proposed including recent findings on HBZ after our efforts. PMID:20154469

  14. Murine Typhus, Reunion, France, 2011–2013

    PubMed Central

    Camuset, Guillaume; Socolovschi, Cristina; Moiton, Marie-Pierre; Kuli, Barbara; Foucher, Aurélie; Poubeau, Patrice; Borgherini, Gianandrea; Wartel, Guillaume; Audin, Héla; Raoult, Didier; Filleul, Laurent; Parola, Philippe; Pagès, Fréderic

    2015-01-01

    Murine typhus case was initially identified in Reunion, France, in 2012 in a tourist. Our investigation confirmed 8 autochthonous cases that occurred during January 2011–January 2013 in Reunion. Murine typhus should be considered in local patients and in travelers returning from Reunion who have fevers of unknown origin. PMID:25625653

  15. Retroviral transfer of a murine cDNA for multidrug resistance confers pleiotropic drug resistance to cells without prior drug selection

    SciTech Connect

    Guild, B.C.; Mulligan, R.C.; Gros, P.; Housman, D.E.

    1988-03-01

    The authors have constructed a retrovirus expression vector that carries the murine mdr cDNA transcribed under the control of the human H4 histone promoter to examine the feasibility of efficiently transferring a multidrug resistance phenotype to cells without requiring drug selection. This approach will facilitate the transfer of mdr cDNA to hematopoietic progenitor cells for the study of multidrug resistance in vivo. The retrovirus vector pHmdr has been used for transmission and expression of the mdr cDNA in initially drug-sensitive NIH 3T3 fibroblasts. Selection of pHmdr infectants in the cytotoxic agents colchicine or doxorubicin gave rise to highly multidrug-resistant colonies containing a single gene copy of the vector. Moreover, in the analysis of 12 cloned unselected NIH 3T3 cell infectants, a multidrug resistance phenotype was conferred by as few as two copies of the pHmdr vector. Overexpression of the mdr cDNA in drug-selected and unselected pHmdr infectants was directly related to cell survival in three cytotoxic agents tested. These results hold significant implications for the study of multidrug resistance in vivo.

  16. Characterization of mouse cellular deoxyribonucleic acid homologous to Abelson murine leukemia virus-specific sequences.

    PubMed Central

    Dale, B; Ozanne, B

    1981-01-01

    The genome of Abelson murine leukemia virus (A-MuLV) consists of sequences derived from both BALB/c mouse deoxyribonucleic acid and the genome of Moloney murine leukemia virus. Using deoxyribonucleic acid linear intermediates as a source of retroviral deoxyribonucleic acid, we isolated a recombinant plasmid which contained 1.9 kilobases of the 3.5-kilobase mouse-derived sequences found in A-MuLV (A-MuLV-specific sequences). We used this clone, designated pSA-17, as a probe restriction enzyme and Southern blot analyses to examine the arrangement of homologous sequences in BALB/c deoxyribonucleic acid (endogenous Abelson sequences). The endogenous Abelson sequences within the mouse genome were interrupted by noncoding regions, suggesting that a rearrangement of the cell sequences was required to produce the sequence found in the virus. Endogenous Abelson sequences were arranged similarly in mice that were susceptible to A-MuLV tumors and in mice that were resistant to A-MuLV tumors. An examination of three BALB/c plasmacytomas and a BALB/c early B-cell tumor likewise revealed no alteration in the arrangement of the endogenous Abelson sequences. Homology to pSA-17 was also observed in deoxyribonucleic acids prepared from rat, hamster, chicken, and human cells. An isolate of A-MuLV which encoded a 160,000-dalton transforming protein (P160) contained 700 more base pairs of mouse sequences than the standard A-MuLV isolate, which encoded a 120,000-dalton transforming protein (P120). Images PMID:9279386

  17. Transplanted human bone marrow progenitor subtypes stimulate endogenous islet regeneration and revascularization.

    PubMed

    Bell, Gillian I; Broughton, Heather C; Levac, Krysta D; Allan, David A; Xenocostas, Anargyros; Hess, David A

    2012-01-01

    Transplanted murine bone marrow (BM) progenitor cells recruit to the injured pancreas and induce endogenous beta cell proliferation to improve islet function. To enrich for analogous human progenitor cell types that stimulate islet regeneration, we purified human BM based on high-aldehyde dehydrogenase activity (ALDH(hi)), an enzymatic function conserved in hematopoietic, endothelial, and mesenchymal progenitor lineages. We investigated the contributions of ALDH(hi) mixed progenitor cells or culture-expanded, ALDH-purified multipotent stromal cell (MSC) subsets to activate endogenous programs for islet regeneration after transplantation into streptozotocin-treated NOD/SCID mice. Intravenous injection of uncultured BM ALDH(hi) cells improved systemic hyperglycemia and augmented insulin secretion by increasing islet size and vascularization, without increasing total islet number. Augmented proliferation within regenerated endogenous islets and associated vascular endothelium indicated the induction of islet-specific proliferative and pro-angiogenic programs. Although cultured MSC from independent human BM samples showed variable capacity to improve islet function, and prolonged expansion diminished hyperglycemic recovery, transplantation of ALDH-purified regenerative MSC reduced hyperglycemia and augmented total beta cell mass by stimulating the formation of small beta cell clusters associated with the ductal epithelium, without evidence of increased islet vascularization or Ngn3(+) endocrine precursor activation. Thus, endogenous islet recovery after progenitor cell transplantation can occur via distinct regenerative mechanisms modulated by subtypes of progenitor cells administered. Further, understanding of how these islet regenerative and pro-angiogenic programs are activated by specific progenitor subsets may provide new approaches for combination cellular therapies to combat diabetes. PMID:21417581

  18. Feedback Response to Selective Depletion of Endogenous Carbon Monoxide in the Blood.

    PubMed

    Kitagishi, Hiroaki; Minegishi, Saika; Yumura, Aki; Negi, Shigeru; Taketani, Shigeru; Amagase, Yoko; Mizukawa, Yumiko; Urushidani, Tetsuro; Sugiura, Yukio; Kano, Koji

    2016-04-27

    The physiological roles of endogenous carbon monoxide (CO) have not been fully understood because of the difficulty in preparing a loss-of-function phenotype of this molecule. Here, we have utilized in vivo CO receptors, hemoCDs, which are the supramolecular 1:1 inclusion complexes of meso-tetrakis(4-sulfonatophenyl)porphinatoiron(II) with per-O-methylated β-cyclodextrin dimers. Three types of hemoCDs (hemoCD1, hemoCD2, and hemoCD3) that exhibit different CO-affinities have been tested as CO-depleting agents in vivo. Intraperitoneally administered hemoCD bound endogenous CO within the murine circulation, and was excreted in the urine along with CO in an affinity-dependent manner. The sufficient administration of hemoCD that has higher CO-affinity than hemoglobin (Hb) produced a pseudoknockdown state of CO in the mouse in which heme oxygenase-1 (HO-1) was markedly induced in the liver, causing the acceleration of endogenous CO production to maintain constant CO-Hb levels in the blood. The contents of free hemin and bilirubin in the blood plasma of the treated mice significantly increased upon removal of endogenous CO by hemoCD. Thus, a homeostatic feedback model for the CO/HO-1 system was proposed as follows: HemoCD primarily removes CO from cell-free CO-Hb. The resulting oxy-Hb is quickly oxidized to met-Hb by oxidant(s) such as hydrogen peroxide in the blood plasma. The met-Hb readily releases free hemin that directly induces HO-1 in the liver, which metabolizes the hemin into iron, biliverdin, and CO. The newly produced CO binds to ferrous Hb to form CO-Hb as an oxidation-resistant state. Overall, the present system revealed the regulatory role of CO for maintaining the ferrous/ferric balance of Hb in the blood. PMID:27057920

  19. A human TRIM5alpha B30.2/SPRY domain mutant gains the ability to restrict and prematurely uncoat B-tropic murine leukemia virus.

    PubMed

    Diaz-Griffero, Felipe; Perron, Michel; McGee-Estrada, Kathleen; Hanna, Robert; Maillard, Pierre V; Trono, Didier; Sodroski, Joseph

    2008-09-01

    Human TRIM5alpha restricts N-tropic murine leukemia virus (N-MLV) but not B-tropic MLV (B-MLV) infection. Here we study B30.2/SPRY domain mutants of human TRIM5alpha that acquire the ability to inhibit B-MLV infection prior to reverse transcription without losing the ability to restrict N-MLV infection. Remarkably, these mutants gain the ability to decrease the amount of particulate B-MLV capsids in the cytosol of infected cells. In addition, these mutants gain the ability to restrict SIV(mac) and HIV-2 infection. B-MLV and SIV(mac) infections were blocked by the mutant TRIM5alpha proteins prior to reverse transcription. Thus, the range of retroviruses restricted by human TRIM5alpha can be increased by changes in the B30.2/SPRY domain, which also result in the ability to cause premature uncoating of the restricted retroviral capsid. PMID:18586294

  20. Essays on Policy Evaluation with Endogenous Adoption

    ERIC Educational Resources Information Center

    Gentile, Elisabetta

    2011-01-01

    Over the last decade, experimental and quasi-experimental methods have been favored by researchers in empirical economics, as they provide unbiased causal estimates. However, when implementing a program, it is often not possible to randomly assign subjects to treatment, leading to a possible endogeneity bias. This dissertation consists of two…

  1. Endogenous opioids and excessive alcohol consumption.

    PubMed Central

    Gianoulakis, C

    1993-01-01

    Alcohol is one of the most popular drugs of abuse in our society, and alcoholism is an important cause of absenteeism at work and a major health and social problem. Ethanol induces a number of effects, such as disinhibition, a feeling of general well-being, tolerance and physical dependence. Since there are no specific receptors with which ethanol interacts, it has been proposed that ethanol exerts its effects by altering the activity of a number of neuronal and neuroendocrine systems. Studies have indicated that alcohol influences the activity of the dopaminergic, serotonergic and opioidergic systems. The implication of the endogenous opioid system in mediating some of the effects of ethanol is indicated by the observations that some of the behavioral and pharmacological effects of ethanol are similar to those of the opiates. Indeed, injections of small amounts of morphine increased ethanol consumption, while the administration of naltrexone decreased ethanol consumption among rats and other experimental animals, in a number of experimental paradigms, suggesting that endogenous opioids may play an important role in controlling voluntary ethanol consumption. This paper reviews studies of the effects of ethanol on the activity of the endogenous opioid system and on the importance of endogenous opioids in controlling alcohol consumption. PMID:7690585

  2. Solution Properties of Murine Leukemia Virus Gag Protein: Differences from HIV-1 Gag▿

    PubMed Central

    Datta, Siddhartha A. K.; Zuo, Xiaobing; Clark, Patrick K.; Campbell, Stephen J.; Wang, Yun-Xing; Rein, Alan

    2011-01-01

    Immature retrovirus particles are assembled from the multidomain Gag protein. In these particles, the Gag proteins are arranged radially as elongated rods. We have previously characterized the properties of HIV-1 Gag in solution. In the absence of nucleic acid, HIV-1 Gag displays moderately weak interprotein interactions, existing in monomer-dimer equilibrium. Neutron scattering and hydrodynamic studies suggest that the protein is compact, and biochemical studies indicate that the two ends can approach close in three-dimensional space, implying the need for a significant conformational change during assembly. We now describe the properties of the Gag protein of Moloney murine leukemia virus (MLV), a gammaretrovirus. We found that this protein is very different from HIV-1 Gag: it has much weaker protein-protein interaction and is predominantly monomeric in solution. This has allowed us to study the protein by small-angle X-ray scattering and to build a low-resolution molecular envelope for the protein. We found that MLV Gag is extended in solution, with an axial ratio of ∼7, comparable to its dimensions in immature particles. Mutational analysis suggests that runs of prolines in its matrix and p12 domains and the highly charged stretch at the C terminus of its capsid domain all contribute to this extended conformation. These differences between MLV Gag and HIV-1 Gag and their implications for retroviral assembly are discussed. PMID:21917964

  3. Solution Properties of Murine Leukemia Virus Gag Protein: Differences from HIV-1 Gag

    SciTech Connect

    Datta, Siddhartha A.K.; Zuo, Xiaobing; Clark, Patrick K.; Campbell, Stephen J.; Wang, Yun-Xing; Rein, Alan

    2012-05-09

    Immature retrovirus particles are assembled from the multidomain Gag protein. In these particles, the Gag proteins are arranged radially as elongated rods. We have previously characterized the properties of HIV-1 Gag in solution. In the absence of nucleic acid, HIV-1 Gag displays moderately weak interprotein interactions, existing in monomer-dimer equilibrium. Neutron scattering and hydrodynamic studies suggest that the protein is compact, and biochemical studies indicate that the two ends can approach close in three-dimensional space, implying the need for a significant conformational change during assembly. We now describe the properties of the Gag protein of Moloney murine leukemia virus (MLV), a gammaretrovirus. We found that this protein is very different from HIV-1 Gag: it has much weaker protein-protein interaction and is predominantly monomeric in solution. This has allowed us to study the protein by small-angle X-ray scattering and to build a low-resolution molecular envelope for the protein. We found that MLV Gag is extended in solution, with an axial ratio of {approx}7, comparable to its dimensions in immature particles. Mutational analysis suggests that runs of prolines in its matrix and p12 domains and the highly charged stretch at the C terminus of its capsid domain all contribute to this extended conformation. These differences between MLV Gag and HIV-1 Gag and their implications for retroviral assembly are discussed.

  4. Effect of internal genomic sequences of the Moloney murine leukemia virus on replication

    SciTech Connect

    Fomin, I.K.; Lobanova, A.B.; Voitenok, N.N.

    1995-11-01

    Construction and use of retrovirus vectors derived from the Moloney murine leukemia virus (MoMuLV) are described. These vectors, designated minimal vectors, contain the left and right long terminal repeats (LTRs), a binding site for proline tRNA, a polypurine tract (PPT), and a dominant marker for selective introduction of vectors into a packaging cell line, but lack the internal sequences of the virus genome. The experiments showed that the minimal vectors can be replicated and that their titer was approximately 1500-fold lower than that of wild-type vectors. The minimal vectors were shown to contain all the cis-acting sequences necessary for correct reverse transcription. One infectious virion, like wild-type viruses, produced only one provirus. Unlike the avian reticuloendotheliosis virus (REV), {Psi}{sup +} and {Psi}{sup {minus}} genomes of MoMuLV did not compete for virion proteins in the {Psi}2 packaging cell line. When an insert was introduced into a central part of the LTR U5 region, the titer of the minimal vector remained the same, while the titer of the wild-type vector decreased approximately 40-fold. 28 refs., 2 figs., 2 tabs.

  5. Xenotropic Murine Leukemia Virus-Related Virus in Chronic Fatigue Syndrome and Prostate Cancer

    PubMed Central

    2010-01-01

    Xenotropic murine leukemia virus-related virus (XMRV) is a γ retrovirus that has been associated with chronic fatigue syndrome (CFS) and prostate cancer. The search for viral causes of these syndromes was reignited by the finding that RNase L activity was low in hereditary prostate cancer and some CFS patients. The six strains of XMRV that have been sequenced have greater than 99% identity, indicating a new human infection rather than laboratory contamination. DNA, RNA, and proteins from XMRV have been detected in 50% to 67% of CFS patients and in about 3.7% of healthy controls. XMRV infections could be transmitted to permissive cell lines from CFS plasma, suggesting the potential for communicable and blood-borne spread of the virus and potentially CFS. This troubling concept is currently under intense evaluation. The most important steps now are to independently confirm the initial findings; develop reliable assays of biomarkers; and to move on to investigations of XMRV pathophysiology and treatment in CFS, prostate cancer, and potentially other virus-related syndromes, if they exist. PMID:20425007

  6. The BET family of proteins targets Moloney Murine Leukemia Virus integration near transcription start sites

    PubMed Central

    De Rijck, Jan; de Kogel, Christine; Demeulemeester, Jonas; Vets, Sofie; Ashkar, Sara El; Malani, Nirav; Bushman, Frederic D; Landuyt, Bart; Husson, Steven J.; Busschots, Katrien; Gijsbers, Rik; Debyser, Zeger

    2014-01-01

    Summary A hallmark of retroviral replication is integration of the viral genome in the host cell DNA. This characteristic makes retrovirus-based vectors attractive delivery vehicles for gene therapy. However, adverse events in gene therapeutic trials, caused by activation of proto-oncogenes due to Murine Leukemia Virus (MLV)-derived vector integration, hamper their application. Here we show that bromodomain and extraterminal (BET) proteins (BRD2, BRD3 and BRD4) and MLV integrase specifically interact and co-localize within the nucleus of the cell. Inhibition of the BET proteins chromatin interaction via specific bromodomain inhibitors blocks MLV virus replication at the integration step. MLV integration site distribution parallels the chromatin binding profile of BET proteins, and expression of an artificial fusion protein of the BET integrase binding domain with the chromatin interaction domain of the lentiviral targeting factor LEDGF/p75, retargets MLV integration away from TSS and into the body of actively transcribed genes, conform to the Human Immunodeficiency Virus (HIV) integration pattern. Together these data validate BET proteins as MLV integration targeting factors. PMID:24183673

  7. Assembly and composition of intracellular particles formed by Moloney murine leukemia virus.

    PubMed Central

    Hansen, M; Jelinek, L; Jones, R S; Stegeman-Olsen, J; Barklis, E

    1993-01-01

    Assembly of type C retroviruses such as Moloney murine leukemia virus (M-MuLV) ordinarily occurs at the plasma membranes of infected cells and absolutely requires the particle core precursor protein, Pr65gag. Previously we have shown that Pr65gag is membrane associated and that at least a portion of intracellular Pr65gag protein appears to be routed to the plasma membrane by a vesicular transport pathway. Here we show that intracellular particle formation can occur in M-MuLV-infected cells. M-MuLV immature particles were observed by electron microscopy budding into and within rough endoplasmic reticulum, Golgi, and vacuolar compartments. Biochemical fractionation studies indicated that intracellular Pr65gag was present in nonionic detergent-resistant complexes of greater than 150S. Additionally, viral RNA and polymerase functions appeared to be associated with intracellular particles, as were Gag-beta-galactosidase fusion proteins which have the capacity to be incorporated into virions. Immature intracellular particles in postnuclear lysates could be proteolytically processed in vitro to mature forms, while extracellular immature M-MuLV particles remained immature as long as 10 h during incubations. The occurrence of M-MuLV-derived intracellular particles demonstrates that Pr65gag can associate with intracellular membranes and indicates that if a plasma membrane Pr65gag receptor exists, it also can be found in other membrane compartments. These results support the hypothesis that intracellular particles may serve as a virus reservoir during in vivo infections. Images PMID:8350394

  8. In Vitro Assembly of Virus-Like Particles of a Gammaretrovirus, the Murine Leukemia Virus XMRV

    PubMed Central

    Hadravová, Romana; de Marco, Alex; Ulbrich, Pavel; Štokrová, Jitka; Doležal, Michal; Pichová, Iva; Ruml, Tomáš

    2012-01-01

    Immature retroviral particles are assembled by self-association of the structural polyprotein precursor Gag. During maturation the Gag polyprotein is proteolytically cleaved, yielding mature structural proteins, matrix (MA), capsid (CA), and nucleocapsid (NC), that reassemble into a mature viral particle. Proteolytic cleavage causes the N terminus of CA to fold back to form a β-hairpin, anchored by an internal salt bridge between the N-terminal proline and the inner aspartate. Using an in vitro assembly system of capsid-nucleocapsid protein (CANC), we studied the formation of virus-like particles (VLP) of a gammaretrovirus, the xenotropic murine leukemia virus (MLV)-related virus (XMRV). We show here that, unlike other retroviruses, XMRV CA and CANC do not assemble tubular particles characteristic of mature assembly. The prevention of β-hairpin formation by the deletion of either the N-terminal proline or 10 initial amino acids enabled the assembly of ΔProCANC or Δ10CANC into immature-like spherical particles. Detailed three-dimensional (3D) structural analysis of these particles revealed that below a disordered N-terminal CA layer, the C terminus of CA assembles a typical immature lattice, which is linked by rod-like densities with the RNP. PMID:22090120

  9. Special coverage: 9th Conference on Retroviruses. New drugs, new data hold promise for next decade of HIV treatment.

    PubMed

    2002-05-01

    Antiretroviral research presented recently at the 9th Conference on Retroviruses and Opportunistic Infections demonstrates that investigators and pharmaceutical companies continue to strive for the next highly potent and easily tolerated anti-HIV drug. Among the new approaches are entry inhibitor drug and second-generation non-nucleoside reverse transcriptase inhibitors. New studies also looked into potency against multidrug-resistant virus and medication regimens that are simpler to take and have fewer side effects. PMID:12030213

  10. Transcriptome Analysis of ESTs from a Chaetognath Reveals a Deep-Branching Clade of Retrovirus-Like Retrotransposons.

    PubMed

    Barthélémy, Roxane M; Casanova, Jean-Paul; Faure, Eric

    2008-01-01

    Chaetognaths constitute a small marine phylum exhibiting several characteristic which are highly unusual in animal genomes, including two classes of both rRNA and protein ribosomal genes. As in this phylum presence of retrovirus-like elements has never been documented, analysis of a published expressed sequence tag (EST) collection of the chaetognath Spadella cephaloptera has been made. Twelve sequences representing transcript sections of reverse transcriptase domain of active retrotransposons were isolated from~11,000 ESTs. Five of them are originated from Gypsy retrovirus-like elements, whereas the other are transcripts from a Bel-Pao LTR-retrotransposon, a Penelope-like element and LINE retrotransposons. Moreover, a part of a putative integrase has also been found. Phylogenetic analyses suggest a deep-branching clade of the retrovirus-like elements, which is in agreement with the probably Cambrian origin of the phylum. Moreover, retrotransposons have not been found in telomeric-like transcripts which are probably constituted by both vertebrate and arthropod canonical repeats. PMID:19440464

  11. Transcriptome Analysis of ESTs from a Chaetognath Reveals a Deep-Branching Clade of Retrovirus-Like Retrotransposons

    PubMed Central

    Barthélémy, Roxane M; Casanova, Jean-Paul; Faure, Eric

    2008-01-01

    Chaetognaths constitute a small marine phylum exhibiting several characteristic which are highly unusual in animal genomes, including two classes of both rRNA and protein ribosomal genes. As in this phylum presence of retrovirus-like elements has never been documented, analysis of a published expressed sequence tag (EST) collection of the chaetognath Spadella cephaloptera has been made. Twelve sequences representing transcript sections of reverse transcriptase domain of active retrotransposons were isolated from~11,000 ESTs. Five of them are originated from Gypsy retrovirus