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1

Essential Bacillus subtilis genes  

PubMed Central

To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among ?4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden–Meyerhof–Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

Kobayashi, K.; Ehrlich, S. D.; Albertini, A.; Amati, G.; Andersen, K. K.; Arnaud, M.; Asai, K.; Ashikaga, S.; Aymerich, S.; Bessieres, P.; Boland, F.; Brignell, S. C.; Bron, S.; Bunai, K.; Chapuis, J.; Christiansen, L. C.; Danchin, A.; Debarbouille, M.; Dervyn, E.; Deuerling, E.; Devine, K.; Devine, S. K.; Dreesen, O.; Errington, J.; Fillinger, S.; Foster, S. J.; Fujita, Y.; Galizzi, A.; Gardan, R.; Eschevins, C.; Fukushima, T.; Haga, K.; Harwood, C. R.; Hecker, M.; Hosoya, D.; Hullo, M. F.; Kakeshita, H.; Karamata, D.; Kasahara, Y.; Kawamura, F.; Koga, K.; Koski, P.; Kuwana, R.; Imamura, D.; Ishimaru, M.; Ishikawa, S.; Ishio, I.; Le Coq, D.; Masson, A.; Mauel, C.; Meima, R.; Mellado, R. P.; Moir, A.; Moriya, S.; Nagakawa, E.; Nanamiya, H.; Nakai, S.; Nygaard, P.; Ogura, M.; Ohanan, T.; O'Reilly, M.; O'Rourke, M.; Pragai, Z.; Pooley, H. M.; Rapoport, G.; Rawlins, J. P.; Rivas, L. A.; Rivolta, C.; Sadaie, A.; Sadaie, Y.; Sarvas, M.; Sato, T.; Saxild, H. H.; Scanlan, E.; Schumann, W.; Seegers, J. F. M. L.; Sekiguchi, J.; Sekowska, A.; Seror, S. J.; Simon, M.; Stragier, P.; Studer, R.; Takamatsu, H.; Tanaka, T.; Takeuchi, M.; Thomaides, H. B.; Vagner, V.; van Dijl, J. M.; Watabe, K.; Wipat, A.; Yamamoto, H.; Yamamoto, M.; Yamamoto, Y.; Yamane, K.; Yata, K.; Yoshida, K.; Yoshikawa, H.; Zuber, U.; Ogasawara, N.

2003-01-01

2

The Human Cytomegalovirus Gene Products Essential for Late Viral Gene Expression Assemble into Prereplication Complexes before Viral DNA Replication?  

PubMed Central

The regulation of human cytomegalovirus (HCMV) late gene expression by viral proteins is poorly understood, and these viral proteins could be targets for novel antivirals. HCMV open reading frames (ORFs) UL79, -87, and -95 encode proteins with homology to late gene transcription factors of murine gammaherpesvirus 68 ORFs 18, 24, and 34, respectively. To determine whether these HCMV proteins are also essential for late gene transcription of a betaherpesvirus, we mutated HCMV ORFs UL79, -87, and -95. Cells were infected with the recombinant viruses at high and low multiplicities of infection (MOIs). While viral DNA was detected with the recombinant viruses, infectious virus was not detected unless the wild-type viral proteins were expressed in trans. At a high MOI, mutation of ORF UL79, -87, or -95 had no effect on the level of major immediate-early (MIE) gene expression or viral DNA replication, but late viral gene expression from the UL44, -75, and -99 ORFs was not detected. At a low MOI, preexpression of UL79 or -87, but not UL95, in human fibroblast cells negatively affected the level of MIE viral gene expression and viral DNA replication. The products of ORFs UL79, -87, and -95 were expressed as early viral proteins and recruited to prereplication complexes (pre-RCs), along with UL44, before the initiation of viral DNA replication. All three HCMV ORFs are indispensable for late viral gene expression and viral growth. The roles of UL79, -87, and -95 in pre-RCs for late viral gene expression are discussed.

Isomura, Hiroki; Stinski, Mark F.; Murata, Takayuki; Yamashita, Yoriko; Kanda, Teru; Toyokuni, Shinya; Tsurumi, Tatsuya

2011-01-01

3

Lichenicidin Biosynthesis in Escherichia coli: licFGEHI Immunity Genes Are Not Essential for Lantibiotic Production or Self-Protection ?  

PubMed Central

This study demonstrated, for the first time, that immunity genes licFGEHI are not essential for self-protection and production of the two-component lantibiotic lichenicidin in the Gram-negative heterologous host Escherichia coli BLic5. Additionally, it was experimentally demonstrated that lichenicidin lantibiotics are active against the E. coli imp4213 strain, a mutant strain possessing a permeable outer membrane.

Caetano, Tania; Krawczyk, Joanna M.; Mosker, Eva; Sussmuth, Roderich D.; Mendo, Sonia

2011-01-01

4

The PKS4 gene of Fusarium graminearum is essential for zearalenone production.  

PubMed

Zearalenones are produced by several Fusarium species and can cause reproductive problems in animals. Some aurofusarin mutants of Fusarium pseudograminearum produce elevated levels of zearalenone (ZON), one of the estrogenic mycotoxins comprising the zearalenones. An analysis of transcripts from polyketide synthase genes identified in the Fusarium graminearum database was carried out for these mutants. PKS4 was the only gene with an enoyl reductase domain that had a higher level of transcription in the aurofusarin mutants than in the wild type. An Agrobacterium tumefaciens-mediated transformation protocol was used to replace the central part of the PKS4 gene with a hygB resistance gene through double homologous recombination in an F. graminearum strain producing a high level of ZON. PCR and Southern analysis of transformants were used to identify isolates with single insertional replacements of PKS4. High-performance liquid chromatography analysis showed that the PKS4 replacement mutant did not produce ZON. Thus, PKS4 encodes an enzyme required for the production of ZON in F. graminearum. Barley root infection studies revealed no alteration in the pathogenicity of the PKS4 mutant compared to the pathogenicity of the wild type. The expression of PKS13, which is located in the same cluster as PKS4, decreased dramatically in the mutant, while transcription of PKS4 was unchanged. This differential expression may indicate that ZON or its derivatives do not regulate expression of PKS4 and that the PKS4-encoded protein or its product stimulates expression of PKS13. Furthermore, both the lack of aurofusarin and ZON influenced the expression of other polyketide synthases, demonstrating that one polyketide can influence the expression of others. PMID:16751498

Lysøe, Erik; Klemsdal, Sonja S; Bone, Karen R; Frandsen, Rasmus J N; Johansen, Thomas; Thrane, Ulf; Giese, Henriette

2006-06-01

5

Essential Learning Products  

NSDL National Science Digital Library

Formerly TeacherNet, Essential Learning Products caters to the educational resource needs of K-8 educators, and is certainly one that is worth taking some time to browse through. Developed by the Highlights educational products group, the site contains opportunities for educators to join various discussion lists, classroom resources (such as lesson plans), and links to the webpages of various classrooms around the United States. One potentially entertaining (and also therapeutic) feature is the "Laugh Lines" section, were educators can submit their various humorous classroom experiences. The bulletin boards are also worth checking out, as they can offer quick answers to any number of topics, such as handwriting, use of the Internet in the classroom, and literature. The site is rounded out by a nice area set aside for discussion and resources specifically designated for student teachers.

6

The PKS4 Gene of Fusarium graminearum Is Essential for Zearalenone Production  

Microsoft Academic Search

Zearalenones are produced by several Fusarium species and can cause reproductive problems in animals. Some aurofusarin mutants of Fusarium pseudograminearum produce elevated levels of zearalenone (ZON), one of the estrogenic mycotoxins comprising the zearalenones. An analysis of transcripts from polyketide synthase genes identified in the Fusarium graminearum database was carried out for these mutants. PKS4 was the only gene with

E. Lysoe; Sonja S. Klemsdal; Karen R. Bone; Rasmus J. N. Frandsen; Thomas Johansen; Ulf Thrane; Henriette Giese

2006-01-01

7

Genes essential for morphological development and antibiotic production in Streptomyces coelicolor are targets of BldD during vegetative growth.  

PubMed

BldD is a transcriptional regulator essential for morphological development and antibiotic production in Streptomyces coelicolor. Here we identify the BldD regulon by means of chromatin immunoprecipitation-microarray analysis (ChIP-chip). The BldD regulon encompasses ~167 transcriptional units, of which more than 20 are known to play important roles in development (e.g. bldA, bldC, bldH/adpA, bldM, bldN, ssgA, ssgB, ftsZ, whiB, whiG, smeA-ssfA) and/or secondary metabolism (e.g. nsdA, cvn9, bldA, bldC, leuA). Strikingly, 42 BldD target genes (~25% of the regulon) encode regulatory proteins, stressing the central, pleiotropic role of BldD. Almost all BldD binding sites identified by ChIP-chip are present in the promoters of the target genes. An exception is the tRNA gene bldA, where BldD binds within the region encoding the primary transcript, immediately downstream of the position corresponding to the processed, mature 3 end of the tRNA. Through gene overexpression, we identified a novel BldD target gene (cdgA) that influences differentiation and antibiotic production. cdgA encodes a GGDEF domain protein, implicating c-di-GMP in the regulation of Streptomyces development. Sequence analysis of the upstream regions of the complete regulon identified a 15 bp inverted repeat that functions as a high-affinity binding site for BldD, as was shown by electrophoretic mobility shift assays and DNase I footprinting analysis. High-scoring copies of the BldD binding site were found at relevant positions in the genomes of other bacteria containing a BldD homologue, suggesting the role of BldD is conserved in sporulating actinomycetes. PMID:20979333

den Hengst, Chris D; Tran, Ngat T; Bibb, Maureen J; Chandra, Govind; Leskiw, Brenda K; Buttner, Mark J

2010-10-01

8

A highly conserved baculovirus gene p48 (ac103) is essential for BV production and ODV envelopment  

SciTech Connect

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) p48 (ac103) is a highly conserved baculovirus gene of unknown function. In the present study, we generated a knockout of the p48 gene in an AcMNPV bacmid and investigated the role of P48 in baculovirus life cycle. The p48-null Bacmid vAc{sup P48-KO-PH-GFP} was unable to propagate in cell culture, while a 'repair' Bacmid vAc{sup P48-REP-PH-GFP} was able to replicate in a manner similar to a wild-type Bacmid vAc{sup PH-GFP}. Titration assays and Western blotting confirmed that vAc{sup P48-KO-PH-GFP} was unable to produce budded viruses (BVs). qPCR analysis showed that p48 deletion did not affect viral DNA replication. Electron microscopy indicated that P48 was required for nucleocapsid envelopment to form occlusion-derived viruses (ODVs) and their subsequent occlusion. Confocal analysis showed that P48 prominently condensed in the centre of the nucleus. Our results demonstrate that P48 plays an essential role in BV production and ODV envelopment in the AcMNPV life cycle.

Yuan Meijin; Wu Wenbi; Liu Chao; Wang Yanjie; Hu Zhaoyang [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China); Yang Kai [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China)], E-mail: yangkai@mail.sysu.edu.cn; Pang Yi [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China)

2008-09-15

9

Gene essentiality determines chromosome organisation in bacteria  

PubMed Central

In Escherichia coli and Bacillus subtilis, essentiality, not expressivity, drives the distribution of genes between the two replicating strands. Although essential genes tend to be coded in the leading replicating strand, the underlying selective constraints and the evolutionary extent of these findings have still not been subject to comparative studies. Here, we extend our previous analysis to the genomes of low G + C firmicutes and ?-proteobacteria, and in a second step to all sequenced bacterial genomes. The inference of essentiality by homology allows us to show that essential genes are much more frequent in the leading strand than other genes, even when compared with non- essential highly expressed genes. Smaller biases were found in the genomes of obligatory intracellular bacteria, for which the assignment of essentiality by homology from fast growing free-living bacteria is most problematic. Cross-comparisons used to assess potential errors in the assignment of essentiality by homology revealed that, in most cases, variations in the assignment criteria have little influence on the overall results. Essential genes tend to be more conserved in the leading strand than average genes, which is consistent with selection for this positioning and may impose a strong constraint on chromosomal rearrangements. These results indicate that essentiality plays a fundamental role in the distribution of genes in most bacterial genomes.

Rocha, Eduardo P. C.; Danchin, Antoine

2003-01-01

10

The Epstein-Barr Virus BcRF1 Gene Product Is a TBP-Like Protein with an Essential Role in Late Gene Expression  

PubMed Central

That the expression of late genes is coupled to viral genome replication is well established for all herpesviruses, but the exact mechanisms of their regulation, especially by viral proteins, are poorly understood. Here, we report the identification of the Epstein-Barr virus (EBV) early protein BcRF1 as a viral factor crucial for the activation of late gene transcription following viral DNA replication during the productive cycle. In order to study the function of the BcRF1 protein, we constructed a recombinant EBV lacking this gene. In HEK293 cells, this recombinant virus underwent normal DNA replication during the productive cycle but failed to express high levels of late gene transcripts or proteins, resulting in a nonproductive infection. Interestingly, a TATT motif is present in the promoter of most EBV late genes, at the position of the TATA box. We show here that BcRF1 forms a complex with the TATT motif and that this interaction is required for activation of late viral gene expression. Moreover, our results suggest that BcRF1 acts via interaction with other viral proteins.

Kadjouf, Faouzi; Mariame, Bernard

2012-01-01

11

The smaller of two overlapping cheA gene products is not essential for chemotaxis in Escherichia coli.  

PubMed Central

The cheA locus of Escherichia coli encodes two similar proteins, CheAL (654 amino acids) and CheAS (557 amino acids), which are made by initiating translation from different in-frame start sites [start(L) and start(S)]. CheAL plays an essential role in chemotactic signaling. It autophosphorylates at a histidine residue (His-48) and then donates this phosphate to response regulator proteins that modulate flagellar rotation and sensory adaptation. CheAS lacks the first 97 amino acids of CheAL, including the phosphorylation site at His-48. Although it is unable to autophosphorylate, CheAS can form heterodimers with mutant CheAL subunits to restore kinase function and chemoreceptor control of autophosphorylation activity. To determine whether these or other activities of CheAS are important for chemotaxis, we constructed cheA lesions that abrogated CheAS expression. Mutants in which the CheAS start codon was changed from methionine to isoleucine (M98I) or glutamine (M98Q) retained chemotactic ability, ranging from 50% (M98Q) to 80% (M98I) of wild-type function. These partial defects could not be alleviated by supplying CheAS from a specialized transducing phage, indicating that the lesions in CheAL--not the lack of CheAS--were responsible for the reduced chemotactic ability. In other respects, the behavior of the M98I mutant was essentially normal. Its flagellar rotation pattern was indistinguishable from wild type, and it exhibited wild-type detection thresholds and peak positions in capillary chemotaxis assays. The lack of any substantive defect in this start(S) mutant argues that CheAS makes a negligible contribution to chemotactic ability in the laboratory. Whether it has functional significance in other settings remains to be seen.

Sanatinia, H; Kofoid, E C; Morrison, T B; Parkinson, J S

1995-01-01

12

Essential Bacterial Functions Encoded by Gene Pairs??  

PubMed Central

To address the need for new antibacterials, a number of bacterial genomes have been systematically disrupted to identify essential genes. Such programs have focused on the disruption of single genes and may have missed functions encoded by gene pairs or multiple genes. In this work, we hypothesized that we could predict the identity of pairs of proteins within one organism that have the same function. We identified 135 putative protein pairs in Bacillus subtilis and attempted to disrupt the genes forming these, singly and then in pairs. The single gene disruptions revealed new genes that could not be disrupted individually and other genes required for growth in minimal medium or for sporulation. The pairwise disruptions revealed seven pairs of proteins that are likely to have the same function, as the presence of one protein can compensate for the absence of the other. Six of these pairs are essential for bacterial viability and in four cases show a pattern of species conservation appropriate for potential antibacterial development. This work highlights the importance of combinatorial studies in understanding gene duplication and identifying functional redundancy.

Thomaides, Helena B.; Davison, Ella J.; Burston, Lisa; Johnson, Hazel; Brown, David R.; Hunt, Alison C.; Errington, Jeffery; Czaplewski, Lloyd

2007-01-01

13

AcMNPV ac143 (odv-e18) is essential for mediating budded virus production and is the 30th baculovirus core gene.  

PubMed

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac143 (odv-e18) is a late gene that encodes for a predicted 9.6 kDa structural protein that locates to the occlusion derived viral envelope and viral induced intranuclear microvesicles [Braunagel, S.C., He, H., Ramamurthy, P., and Summers, M.D. (1996). Transcription, translation, and cellular localization of three Autographa californica nuclear polyhedrosis virus structural proteins: ODV-E18, ODV-E35, and ODV-EC27. Virology 222, 100-114.]. In this study we demonstrate that ac143 is actually a previously unrecognized core gene and that it is essential for mediating budded virus production. To examine the role of ac143 in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac143 knockout (KO) virus (AcBAC(ac142)(REP-ac143KO)). Fluorescence and light microscopy showed that infection by AcBAC(ac142)(REP-ac143KO) is limited to a single cell and titration assays confirmed that AcBAC(ac142)(REP-ac143KO) was unable to produce budded virus (BV). Progression to very late phases of the viral infection was evidenced by the development of occlusion bodies in the nuclei of transfected cells. This correlated with the fact that viral DNA replication was unaffected in AcBAC(ac142)(REP-ac143KO) transfected cells. The entire ac143 promoter, which includes three late promoter motifs, is contained within the ac142 open reading frame. Different deletion mutants of this region showed that the integrity of the ac142-ac143 core gene cluster was required for the bacmids to display wild-type patterns of viral replication, BV production and RNA transcription. PMID:18328526

McCarthy, Christina B; Theilmann, David A

2008-05-25

14

AcMNPV ac143 (odv-e18) is essential for mediating budded virus production and is the 30th baculovirus core gene  

SciTech Connect

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac143 (odv-e18) is a late gene that encodes for a predicted 9.6 kDa structural protein that locates to the occlusion derived viral envelope and viral induced intranuclear microvesicles [Braunagel, S.C., He, H., Ramamurthy, P., and Summers, M.D. (1996). Transcription, translation, and cellular localization of three Autographa californica nuclear polyhedrosis virus structural proteins: ODV-E18, ODV-E35, and ODV-EC27. Virology 222, 100-114.]. In this study we demonstrate that ac143 is actually a previously unrecognized core gene and that it is essential for mediating budded virus production. To examine the role of ac143 in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac143 knockout (KO) virus (AcBAC{sup ac142REP-ac143KO}). Fluorescence and light microscopy showed that infection by AcBAC{sup ac142REP-ac143KO} is limited to a single cell and titration assays confirmed that AcBAC{sup ac142REP-ac143KO} was unable to produce budded virus (BV). Progression to very late phases of the viral infection was evidenced by the development of occlusion bodies in the nuclei of transfected cells. This correlated with the fact that viral DNA replication was unaffected in AcBAC{sup ac142REP-ac143KO} transfected cells. The entire ac143 promoter, which includes three late promoter motifs, is contained within the ac142 open reading frame. Different deletion mutants of this region showed that the integrity of the ac142-ac143 core gene cluster was required for the bacmids to display wild-type patterns of viral replication, BV production and RNA transcription.

McCarthy, Christina B. [Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, British Columbia, V0H 1Z0 (Canada); Theilmann, David A. [Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, British Columbia, V0H 1Z0 (Canada)], E-mail: TheilmannD@agr.gc.ca

2008-05-25

15

Protein-protein association and cellular localization of four essential gene products encoded by tellurite resistance-conferring cluster "ter" from pathogenic Escherichia coli.  

PubMed

Gene cluster "ter" conferring high tellurite resistance has been identified in various pathogenic bacteria including Escherichia coli O157:H7. However, the precise mechanism as well as the molecular function of the respective gene products is unclear. Here we describe protein-protein association and localization analyses of four essential Ter proteins encoded by minimal resistance-conferring fragment (terBCDE) by means of recombinant expression. By using a two-plasmid complementation system we show that the overproduced single Ter proteins are not able to mediate tellurite resistance, but all Ter members play an irreplaceable role within the cluster. We identified several types of homotypic and heterotypic protein-protein associations among the Ter proteins by in vitro and in vivo pull-down assays and determined their cellular localization by cytosol/membrane fractionation. Our results strongly suggest that Ter proteins function involves their mutual association, which probably happens at the interface of the inner plasma membrane and the cytosol. PMID:23989928

Valkovicova, Lenka; Vavrova, Silvia Minarikova; Mravec, Jozef; Grones, Jozef; Turna, Jan

2013-12-01

16

Evidence that the UL84 gene product of human cytomegalovirus is essential for promoting oriLyt-dependent DNA replication and formation of replication compartments in cotransfection assays.  

PubMed Central

The protein products of 11 viral genomic loci cooperate in a transient cotransfection assay to mediate lytic-phase DNA replication of oriLyt, the human cytomegalovirus (HCMV) origin of replication. Six of these genes have homology with the well-characterized herpes simplex virus replication genes and encode core replication machinery proteins that are typically essential for DNA synthesis. The remaining five HCMV gene loci, initially referred to as auxiliary components, include several known immediate-early (IE) transcriptional regulatory proteins as well as genes encoding functionally uncharacterized polypeptides. Some or all of the auxiliary components may be necessary in trans to replicate the HCMV oriLyt only because they are required for efficient expression or transactivation of the native early promoters and 3' processing elements included in the genomic clones. Therefore, we reassessed the requirements for the auxiliary components by adding constitutive heterologous promoters and control signals to the coding regions and carrying out transient DpnI replication assays in cotransfected Vero cells. The results revealed that in the presence of the UL69 posttranscriptional activator and the remaining auxiliary polypeptides, UL84 was the only auxiliary component that could not be omitted to obtain oriLyt-dependent DNA replication. Nevertheless, in human diploid fibroblasts, some additional auxiliary loci as well as UL84 were critical. There was also an obligatory requirement for UL84, in cooperation with two other auxiliary factors, UL112-113 and IE2, and the core machinery, to constitute the minimal HCMV proteins necessary to direct oriLyt-dependent DNA amplification. However, the Epstein-Barr virus core replication genes could substitute for the HCMV core genes, and in these circumstances, UL84 alone directed amplification of HCMV oriLyt. Moreover, there was also an absolute requirement for UL84 along with the core and other auxiliary factors for the formation of intranuclear replication compartments as assayed by immunofluorescence in transient DNA cotransfection assays. These compartments were typical of those associated with active viral DNA replication in HCMV-infected cells, they incorporated pulse-labeled bromodeoxyuridine, and their formation was both phosphonoacetic acid sensitive and oriLyt dependent. These results demonstrate that UL84 is obligatory for both intranuclear replication compartment formation and origin-dependent DNA amplification and suggest that it is a key viral component in promoting the initiation of HCMV oriLyt-directed DNA replication.

Sarisky, R T; Hayward, G S

1996-01-01

17

Exploring the Optimal Strategy to Predict Essential Genes in Microbes  

PubMed Central

Accurately predicting essential genes is important in many aspects of biology, medicine and bioengineering. In previous research, we have developed a machine learning based integrative algorithm to predict essential genes in bacterial species. This algorithm lends itself to two approaches for predicting essential genes: learning the traits from known essential genes in the target organism, or transferring essential gene annotations from a closely related model organism. However, for an understudied microbe, each approach has its potential limitations. The first is constricted by the often small number of known essential genes. The second is limited by the availability of model organisms and by evolutionary distance. In this study, we aim to determine the optimal strategy for predicting essential genes by examining four microbes with well-characterized essential genes. Our results suggest that, unless the known essential genes are few, learning from the known essential genes in the target organism usually outperforms transferring essential gene annotations from a related model organism. In fact, the required number of known essential genes is surprisingly small to make accurate predictions. In prokaryotes, when the number of known essential genes is greater than 2% of total genes, this approach already comes close to its optimal performance. In eukaryotes, achieving the same best performance requires over 4% of total genes, reflecting the increased complexity of eukaryotic organisms. Combining the two approaches resulted in an increased performance when the known essential genes are few. Our investigation thus provides key information on accurately predicting essential genes and will greatly facilitate annotations of microbial genomes.

Deng, Jingyuan; Tan, Lirong; Lin, Xiaodong; Lu, Yao; Lu, Long J.

2011-01-01

18

Yeast casein kinase I homologues: an essential gene pair.  

PubMed Central

We report the isolation of an essential pair of Saccharomyces cerevisiae genes that encode protein kinase homologues. The two genes were independently isolated as dosage-dependent suppressors. Increased dosage of YCK1 suppressed defects caused by reduced SNF1 protein kinase activity, and increased dosage of YCK2 relieved sensitivity of wild-type cells to salt stress. The two genes function identically in the two growth assays, and loss of function of either gene alone has no discernible effect on growth. However, loss of function of both genes results in inviability. The two predicted protein products share 77% overall amino acid identity and contain sequence elements conserved among protein kinases. Partial sequence obtained for rabbit casein kinase I shares 64% identity with the two yeast gene products. Moreover, an increase in casein kinase I activity is observed in extracts from cells overexpressing YCK2. Thus YCK1 and YCK2 appear to encode casein kinase I homologues. Images

Robinson, L C; Hubbard, E J; Graves, P R; DePaoli-Roach, A A; Roach, P J; Kung, C; Haas, D W; Hagedorn, C H; Goebl, M; Culbertson, M R

1992-01-01

19

Experimental Determination and System Level Analysis of Essential Genes in Escherichia coli MG1655  

Microsoft Academic Search

Defining the gene products that play an essential role in an organism's functional repertoire is vital to understanding the system level organization of living cells. We used a genetic footprinting technique for a genome-wide assessment of genes required for robust aerobic growth of Escherichia coli in rich media. We identified 620 genes as essential and 3,126 genes as dispensable for

S. Y. Gerdes; M. D. Scholle; J. W. Campbell; G. Balazsi; E. Ravasz; M. D. Daugherty; A. L. Somera; N. C. Kyrpides; I. Anderson; M. S. Gelfand; A. Bhattacharya; V. Kapatral; M. D'Souza; M. V. Baev; Y. Grechkin; F. Mseeh; M. Y. Fonstein; R. Overbeek; A.-L. Barabasi; Z. N. Oltvai; A. L. Osterman

2003-01-01

20

The Agrobacterium tumefaciens virB4 gene product is an essential virulence protein requiring an intact nucleoside triphosphate-binding domain.  

PubMed Central

Products of the approximately 9.5-kb virB operon are proposed to direct the export of T-DNA/protein complexes across the Agrobacterium tumefaciens envelope en route to plant cells. The presence of conserved nucleoside triphosphate (NTP)-binding domains in VirB4 and VirB11 suggests that one or both proteins couple energy, via NTP hydrolysis, to T-complex transport. To assess the importance of VirB4 for virulence, a nonpolar virB4 null mutation was introduced into the pTiA6NC plasmid of strain A348. The 2.37-kb virB4 coding sequence was deleted precisely by oligonucleotide-directed mutagenesis in vitro. The resulting delta virB4 mutation was exchanged for the wild-type allele by two sequential recombination events with the counterselectable Bacillus subtilis sacB gene. Two derivatives, A348 delta B4.4 and A348 delta B4.5, sustained a nonpolar deletion of the wild-type virB4 allele, as judged by Southern blot hybridization and immunoblot analyses with antibodies specific for VirB4, VirB5, VirB10, and VirB11. Transcription of wild-type virB4 from the lac promoter restored virulence to the nonpolar null mutants on a variety of dicotyledonous species, establishing virB4 as an essential virulence gene. A substitution of glutamine for Lys-439 and a deletion of Gly-438, Lys-439, and Thr-440 within the glycine-rich NTP-binding domain (Gly-Pro-Iso-Gly-Arg-Gly-Lys-Thr) abolished complementation of A348 delta B4.4 or A348 delta B4.5, demonstrating that an intact NTP-binding domain is critical for VirB4 function. Merodiploids expressing both the mutant and wild-type virB4 alleles exhibited lower virulence than A348, suggesting that VirB4, a cytoplasmic membrane protein, may contribute as a homo- or heteromultimer to A. tumefaciens virulence. Images

Berger, B R; Christie, P J

1993-01-01

21

The Product of arcR, the Sixth Gene of the arc Operon of Lactobacillus sakei, Is Essential for Expression of the Arginine Deiminase Pathway  

Microsoft Academic Search

Lactobacillus sakei is a lactic acid bacterium commonly used as a starter culture for dry sausage production and can utilize arginine via the arginine deiminase pathway. The arcABCTD cluster of L. sakei has been characterized, and transcriptional studies have shown that its expression is subject to carbon catabolite repression and induction by arginine. Downstream of arcD an additional gene has

Manuel Zuniga; María del Carmen Miralles; G. Perez-Martinez

2002-01-01

22

How to identify essential genes from molecular networks?  

PubMed Central

Background The prediction of essential genes from molecular networks is a way to test the understanding of essentiality in the context of what is known about the network. However, the current knowledge on molecular network structures is incomplete yet, and consequently the strategies aimed to predict essential genes are prone to uncertain predictions. We propose that simultaneously evaluating different network structures and different algorithms representing gene essentiality (centrality measures) may identify essential genes in networks in a reliable fashion. Results By simultaneously analyzing 16 different centrality measures on 18 different reconstructed metabolic networks for Saccharomyces cerevisiae, we show that no single centrality measure identifies essential genes from these networks in a statistically significant way; however, the combination of at least 2 centrality measures achieves a reliable prediction of most but not all of the essential genes. No improvement is achieved in the prediction of essential genes when 3 or 4 centrality measures were combined. Conclusion The method reported here describes a reliable procedure to predict essential genes from molecular networks. Our results show that essential genes may be predicted only by combining centrality measures, revealing the complex nature of the function of essential genes.

del Rio, Gabriel; Koschutzki, Dirk; Coello, Gerardo

2009-01-01

23

Two Oligopeptide-Permease-Encoding Genes in the Clavulanic Acid Cluster of Streptomyces clavuligerus Are Essential for Production of the  Lactamase Inhibitor  

Microsoft Academic Search

orf7 (oppA1) and orf15 (oppA2) are located 8 kb apart in the clavulanic acid gene cluster of Streptomyces clavuligerus and encode proteins which are 48.0% identical. These proteins show sequence similarity to periplasmic oligopeptide-binding proteins. Mutant S. clavuligerus oppA1::acc, disrupted in oppA1, lacks clavu- lanic acid production. Clavulanic acid production is restored by transformation with plasmid pIJ699-oppA1, which carries oppA1,

Luis M. Lorenzana; Rosario Perez-Redondo; Irene Santamarta; J. F. Martin; Paloma Liras

2004-01-01

24

Regional variation in the density of essential genes in mice.  

PubMed

In most species, and particularly in vertebrates, the percentage of genes absolutely required for survival, the essential genes, has not been estimated. To obtain this estimation, we used the mouse as an experimental model to carry out high-efficiency N-ethyl-N-nitrosourea (ENU) mutagenesis screens in two balancer chromosome regions, and compared our results to a third previously published screen. The number of essential genes in each region was predicted based on allele frequencies. We determined that the density of essential genes differs by up to an order of magnitude among genomic regions. This indicates that extrapolating from regional estimates to genome-wide estimates of essential genes has a huge variance. A particularly high density of essential genes on mouse Chromosome 11 coincides with a high degree of regional linkage conservation, providing a possible causal explanation for the density variation. This is the first demonstration of regional variation in essential gene density in the mouse genome. PMID:17480122

Hentges, Kathryn E; Pollock, David D; Liu, Bin; Justice, Monica J

2007-05-01

25

Genetics of germination-arrest factor (GAF) production by Pseudomonas fluorescens WH6: identification of a gene cluster essential for GAF biosynthesis.  

PubMed

The genetic basis of the biosynthesis of the germination-arrest factor (GAF) produced by Pseudomonas fluorescens WH6, and previously identified as 4-formylaminooxyvinylglycine, has been investigated here. In addition to inhibiting the germination of a wide range of grassy weeds, GAF exhibits a selective antimicrobial activity against the bacterial plant pathogen Erwinia amylovora. We utilized the in vitro response of E. amylovora to GAF as a rapid screen for loss-of-function GAF phenotypes generated by transposon mutagenesis. A Tn5 mutant library consisting of 6364 WH6 transformants was screened in this Erwinia assay, resulting in the identification of 18 non-redundant transposon insertion sites that led to loss of GAF production in WH6, as confirmed by TLC analysis. These insertions mapped to five different genes and four intergenic regions. Three of these genes, including two putative regulatory genes (gntR and iopB homologues), were clustered in a 13 kb chromosomal region containing 13 putative ORFs. A GAF mutation identified previously as affecting an aminotransferase also maps to this region. We suggest that three of the genes in this region (a carbamoyltransferase, an aminotransferase and a formyltransferase) encode the enzymes necessary to synthesize dihydroGAF, the putative immediate precursor of GAF in a proposed GAF biosynthetic pathway. RT-qPCR analyses demonstrated that mutations in the gntR and iopB regulatory genes, as well as in a prtR homologue identified earlier as controlling GAF formation, suppressed transcription of at least two of the putative GAF biosynthetic genes (encoding the aminotransferase and formyltransferase) located in this 13 kb region. PMID:23125119

Halgren, Anne; Maselko, Maciej; Azevedo, Mark; Mills, Dallice; Armstrong, Donald; Banowetz, Gary

2013-01-01

26

The ha72 Core Gene of Baculovirus Is Essential for Budded Virus Production and Occlusion-Derived Virus Embedding, and Amino Acid K22 Plays an Important Role in Its Function  

PubMed Central

ha72 of Helicoverpa armigera nucleopolyhedrovirus (a homologue of ac78) was identified as a conserved late baculovirus gene and characterized. HA72 localizes in the intranuclear ring zone. By generating mutants, we showed that HA72 is essential for budded virus (BD) production and occlusion-derived virus (ODV) embedding. HA72 also interacted with P33, a baculoviral sulfhydryl oxidase. A point mutation of amino acid 22 from lysine to glutamic acid curtailed BV production and precluded ODV occlusion as well as interaction with P33.

Huang, Huachao; Wang, Manli; Deng, Fei; Hou, Dianhai; Arif, Basil M.; Wang, Hualin

2014-01-01

27

Mutualistic Polydnaviruses Share Essential Replication Gene Functions with Pathogenic Ancestors  

PubMed Central

Viruses are usually thought to form parasitic associations with hosts, but all members of the family Polydnaviridae are obligate mutualists of insects called parasitoid wasps. Phylogenetic data founded on sequence comparisons of viral genes indicate that polydnaviruses in the genus Bracovirus (BV) are closely related to pathogenic nudiviruses and baculoviruses. However, pronounced differences in the biology of BVs and baculoviruses together with high divergence of many shared genes make it unclear whether BV homologs still retain baculovirus-like functions. Here we report that virions from Microplitis demolitor bracovirus (MdBV) contain multiple baculovirus-like and nudivirus-like conserved gene products. We further show that RNA interference effectively and specifically knocks down MdBV gene expression. Coupling RNAi knockdown methods with functional assays, we examined the activity of six genes in the MdBV conserved gene set that are known to have essential roles in transcription (lef-4, lef-9), capsid assembly (vp39, vlf-1), and envelope formation (p74, pif-1) during baculovirus replication. Our results indicated that MdBV produces a baculovirus-like RNA polymerase that transcribes virus structural genes. Our results also supported a conserved role for vp39, vlf-1, p74, and pif-1 as structural components of MdBV virions. Additional experiments suggested that vlf-1 together with the nudivirus-like gene int-1 also have novel functions in regulating excision of MdBV proviral DNAs for packaging into virions. Overall, these data provide the first experimental insights into the function of BV genes in virion formation.

Burke, Gaelen R.; Thomas, Sarah A.; Eum, Jai H.; Strand, Michael R.

2013-01-01

28

Reduced expression of Autographa californica nucleopolyhedrovirus ORF34, an essential gene, enhances heterologous gene expression  

PubMed Central

Autographa californica multiple nucleopolyhedrovirus ORF34 is part of a transcriptional unit that includes ORF32, encoding a viral fibroblast growth factor (FGF) and ORF33. We identified ORF34 as a candidate for deletion to improve protein expression in the baculovirus expression system based on enhanced reporter gene expression in an RNAi screen of virus genes. However, ORF34 was shown to be an essential gene. To explore ORF34 function, deletion (KO34) and rescue bacmids were constructed and characterized. Infection did not spread from primary KO34 transfected cells and supernatants from KO34 transfected cells could not infect fresh Sf21 cells whereas the supernatant from the rescue bacmids transfection could recover the infection. In addition, budded viruses were not observed in KO34 transfected cells by electron microscopy, nor were viral proteins detected from the transfection supernatants by western blots. These demonstrate that ORF34 is an essential gene with a possible role in infectious virus production.

Salem, Tamer Z.; Zhang, Fengrui; Thiem, Suzanne M.

2012-01-01

29

An Epimerase Gene Essential for Capsule Synthesis in Vibrio vulnificus  

PubMed Central

The extracellular capsule polysaccharide (CPS) of Vibrio vulnificus is a primary virulence factor which allows survival of the bacteria in the human host. To study the genes involved in expression of the capsule, we generated mutants that lost the ability to produce CPS following the insertion of a minitransposon into the genome of an encapsulated, clinical strain of V. vulnificus. A genomic region, from one nonencapsulated mutant, containing the transposon and flanking V. vulnificus DNA was cloned, and a probe complementary to the chromosomal DNA immediately adjacent to the transposon was used to locate this fragment in the genome of the encapsulated parent strain. The fragment, which contained a putative capsule gene, was cloned and, when supplied in trans, complemented the mutation in the nonencapsulated mutant to restore capsule production. In addition, virulence studies, using the 50% lethal dose assay, showed that the restoration of capsule production also restored the virulence of the organism. Sequence analysis of the gene disrupted by the transposon revealed that it matched a nucleotide-sugar epimerase of Vibrio cholerae O139, with 75 and 85% identities at the nucleotide and amino acid levels, respectively. In addition, computer analysis recognized epimerases of various organisms as highly similar to the putative epimerase of V. vulnificus. Finally, a combination of PCR amplification and Southern blotting showed that this epimerase is common to at least 10 strains of V. vulnificus that each express a serologically distinct CPS. Our results indicate that the epimerase gene is essential for capsule expression in V. vulnificus.

Zuppardo, Amy B.; Siebeling, Ronald J.

1998-01-01

30

The six conserved helicase motifs of the UL5 gene product, a component of the herpes simplex virus type 1 helicase-primase, are essential for its function.  

PubMed Central

The UL5 protein of herpes simplex virus type 1, one component of the viral helicase-primase complex, contains six sequence motifs found in all members of a superfamily of DNA and RNA helicases. Although this superfamily contains more than 20 members ranging from bacteria to mammalian cells and their viruses, the importance of these motifs has not been addressed experimentally for any one of them. In this study, we have examined the functional significance of these six motifs for the UL5 protein through the introduction of site-specific mutations resulting in single amino acid substitutions of the most highly conserved residues within each motif. A transient replication complementation assay was used to test the effect of each mutation on the function of the UL5 protein in viral DNA replication. In this assay, a mutant UL5 protein expressed from an expression clone is used to complement a replication-deficient null mutant with a mutation in the UL5 gene for the amplification of herpes simplex virus origin-containing plasmids. Eight mutations in conserved regions and three similar mutations in nonconserved regions of the UL5 gene were analyzed, and the results indicate that all six conserved motifs are essential to the function of UL5 protein in viral DNA replication; on the other hand, mutations in nonconserved regions are tolerated. These data provide the first direct evidence for the importance of these conserved regions in any member of the superfamily of DNA and RNA helicases. In addition, three motif mutations were introduced into the viral genome, and the phenotypic analyses of these mutants are consistent with results from the transient replication complementation assay. The ability of these three mutant UL5 proteins to form specific interactions with other members of the helicase-primase complex, UL8 and UL52, indicates that the functional domains required for replication activity of UL5 are separable from domains responsible for protein-protein interactions. It is anticipated that this type of structure-function analysis will lead to the identification of protein domains that contribute not only to the enzymatic activities of helicase or primase but also to protein-protein interactions within members of the complex. Images

Zhu, L A; Weller, S K

1992-01-01

31

Essential genes of a minimal bacterium  

Microsoft Academic Search

Mycoplasma genitalium has the smallest genome of any organism that can be grown in pure culture. It has a minimal metabolism and little genomic redundancy. Consequently, its genome is expected to be a close approximation to the minimal set of genes needed to sustain bacterial life. Using global transposon mutagenesis, we isolated and characterized gene disruption mutants for 100 different

John I. Glass; Nacyra Assad-Garcia; Nina Alperovich; Shibu Yooseph; Matthew R. Lewis; Mahir Maruf; Clyde A. Hutchison III; Hamilton O. Smith; J. Craig Venter

2006-01-01

32

The AcMNPV pp31 gene is not essential for productive AcMNPV replication or late gene transcription but appears to increase levels of most viral transcripts  

PubMed Central

The pp31 gene of Autographa californica Multicapsid Nucleopolyhedrovirus (AcMNPV) encodes a phosphorylated DNA binding protein that associates with virogenic stroma in the nuclei of infected cells. Prior studies of pp31 by transient late expression assays suggested that pp31 may play an important role in transcription of AcMNPV late genes (Todd et al., 1995. J. Virol. 69, 968–974) although genetic studies of the closely related BmNPV pp31 gene suggested that pp31 may be dispensable (Gomi et al., 1997. Virology 230, 35–47). In the current study, we examined the role of the pp31 gene in the context of the AcMNPV genome during infection. We used a BACmid-based system to generate a pp31 knockout in the AcMNPV genome. The pp31 knockout was subsequently rescued by reinserting the pp31 gene into the polyhedrin locus of the same virus genome. We found that pp31 was not essential for viral replication although the absence of pp31 resulted in a lower viral titer. Analysis of viral DNA replication in the absence of pp31 showed that the kinetics of viral DNA replication were unaffected. An AcMNPV oligonucleotide microarray was used to compare gene expression from all AcMNPV genes in the presence or absence of pp31. In the absence of pp31 a modest reduction in transcripts was detected for many viral genes (99 genes) while no substantial increase or decrease was observed for 43 genes. Transcripts from 6 genes (p6.9, ORF 97, ORF 60, ORF 98, ORF 102 and chitinase) were reduced by 66% or more compared to the levels detected from the control virus. Microarray results were further examined by qPCR analysis of selected genes. In combination, these data show that deletion of the pp31 gene was not lethal and did not appear to affect viral DNA replication, but resulted in an apparent modest down-regulation of a subset of AcMNPV genes that included both early and late genes.

Yamagishi, Junya; Burnett, Erik D.; Harwood, Steven H.; Blissard, Gary W.

2009-01-01

33

Systematic identification of essential genes by in vitro mariner mutagenesis  

Microsoft Academic Search

Although the complete DNA sequences of several microbial genomes are now available, nearly 40% of the putative genes lack identifiable functions. Comprehensive screens and selections for identifying functional classes of genes are needed to convert sequence data into meaningful biological information. One particularly significant group of bacterial genes consists of those that are essential for growth or viability. Here, we

Brian J. Akerley; Eric J. Rubin; Andrew Camilli; David J. Lampe; Hugh M. Robertson; John J. Mekalanos

1998-01-01

34

Genome Scanning in Haemophilus influenzae for Identification of Essential Genes  

PubMed Central

We have developed a method for identifying essential genes by using an in vitro transposition system, with a small (975 bp) insertional element containing an antibiotic resistance cassette, and mapping these inserts relative to the deduced open reading frames of Haemophilus influenzae by PCR and Southern analysis. Putative essential genes are identified by two methods: mutation exclusion or zero time analysis. Mutation exclusion consists of growing an insertional library and identifying open reading frames that do not contain insertional elements: in a growing population of bacteria, insertions in essential genes are excluded. Zero time analysis consists of monitoring the fate of individual insertions after transformation in a growing culture: the loss of inserts in essential genes is observed over time. Both methods of analysis permit the identification of genes required for bacterial survival. Details of the mutant library construction and the mapping strategy, examples of mutant exclusion, and zero time analysis are presented.

Reich, Karl A.; Chovan, Linda; Hessler, Paul

1999-01-01

35

Processing of Vietnamese Essential Oils and Related Natural Products.  

National Technical Information Service (NTIS)

A project document on processing of Vietnamese Essential Oils and related natural products was drawn up between the United Nations Industrial Development Organization (UNIDO) and the Socialist Republic of Vietnam to develop an essential oils industry by u...

R. Gupta

1990-01-01

36

Pathogenicity and Immunogenicity of a Vaccine Strain of Listeria monocytogenes That Relies on a Suicide Plasmid To Supply an Essential Gene Product  

Microsoft Academic Search

Listeria monocytogenes is a bacterial pathogen that elicits a strong cellular immune response and thus has potential use as a vaccine vector. An attenuated strain, L. monocytogenes dal dat, produced by deletion of two genes (dal and dat) used for D-alanine synthesis, induces cytotoxic T lymphocytes and protective immunity in mice following infection in the presence of D-alanine. In order

Xinyan Zhao; Zhongxia Li; Baiyan Gu; Fred R. Frankel

2005-01-01

37

Chromatin Regulation and Gene Centrality Are Essential for Controlling Fitness Pleiotropy in Yeast  

PubMed Central

Background There are a wide range of phenotypes that are due to loss-of-function or null mutations. Previously, the functions of gene products that distinguish essential from nonessential genes were characterized. However, the functions of products of non-essential genes that contribute to fitness remain minimally understood. Principal Findings Using data from Saccharomyces cerevisiae, we investigated several gene characteristics, which we are able to measure, that are significantly associated with a gene's fitness pleiotropy. Fitness pleiotropy is a measurement of the gene's importance to fitness. These characteristics include: 1) whether the gene's product functions in chromatin regulation, 2) whether the regulation of the gene is influenced by chromatin state, measured by chromatin regulation effect (CRE), 3) whether the gene's product functions as a transcription factor (TF) and the number of genes a TF regulates, 4) whether the gene contains TATA-box, and 5) whether the gene's product is central in a protein interaction network. Partial correlation analysis was used to study how these characteristics interact to influence fitness pleiotropy. We show that all five characteristics that were measured are statistically significantly associated with fitness pleiotropy. However, fitness pleiotropy is not associated with the presence of TATA-box when CRE is controlled. In particular, two characteristics: 1) whether the regulation of a gene is more likely to be influenced by chromatin state, and 2) whether the gene product is central in a protein interaction network measured by the number of protein interactions were found to play the most important roles affecting a gene's fitness pleiotropy. Conclusions These findings highlight the significance of both epigenetic gene regulation and protein interaction networks in influencing the fitness pleiotropy.

Zhou, Linqi; Ma, Xiaotu; Arbeitman, Michelle N.; Sun, Fengzhu

2009-01-01

38

TnAraOut, a transposon-based approach to identify and characterize essential bacterial genes.  

PubMed

Identification of genes that encode essential products provides a promising approach to validation of new antibacterial drug targets. We have developed a mariner-based transposon, TnAraOut, that allows efficient identification and characterization of essential genes by transcriptionally fusing them to an outward-facing, arabinose-inducible promoter, PBAD, located at one end of the transposon. In the absence of arabinose, such TnAraOut fusion strains display pronounced growth defects. Of a total of 16 arabinose-dependent TnAraOut mutants characterized in Vibrio cholerae, four were found to carry insertions upstream of known essential genes (gyrB, proRS, ileRS, and aspRS) whereas the other strains carried insertions upstream of known and hypothetical genes not previously shown to encode essential gene products. One of the essential genes identified by this analysis appears to be unique to V. cholerae and thus may represent an example of a species-specific drug target. PMID:10888841

Judson, N; Mekalanos, J J

2000-07-01

39

Saccharomyces cerevisiae Essential Genes with an Opi? Phenotype  

PubMed Central

The overproduction and secretion of inositol (i.e., Opi?) phenotype is associated with defects in regulation of phospholipid biosynthesis in yeast. Here we report a screen of the essential yeast gene set using a conditional-expression library. This screen identified novel functions previously unknown to affect phospholipid synthesis.

Salas-Santiago, Bryan; Lopes, John M.

2014-01-01

40

A homeobox gene essential for zebrafish notochord development  

Microsoft Academic Search

The notochord is a midline mesodermal structure with an essential patterning function in all vertebrate embryos. Zebrafish floating head (flh) mutants lack a notochord, but develop with prechordal plate and other mesodermal derivatives, indicating that flh functions specifically in notochord development. We show that floating head is the zebrafish homologue of Xnot, a homeobox gene expressed in the amphibian organizer

William S. Talbot; Bill Trevarrow; Marnie E. Halpern; Anna E. Melby; Gist Farr; John H. Postlethwait; Trevor Jowett; Charles B. Kimmel; David Kimelman

1995-01-01

41

Essential technical parameters for effective biogas production  

Microsoft Academic Search

Rising agrarian raw material prices in 2006 had a negative impact on the biogas sector in Germany, leading to the search for potentials for optimisation of production. A problem is the workload of the block-type thermal power station (BTPS). This is caused by biogas process disturbances, construction errors, technical problems and management mistakes as well as by oversizing of the

M. Schlegel; N. Kanswohl; D. Rössel; A. Sakalauskas

42

The devR gene product is characteristic of receivers of two-component regulatory systems and is essential for heterocyst development in the filamentous cyanobacterium Nostoc sp. strain ATCC 29133.  

PubMed Central

Strain UCD 311 is a transposon-induced mutant of Nostoc sp. strain ATC C 29133 that is unable to fix nitrogen in air but does so under anoxic conditions and is able to establish a functional symbiotic association with the hornwort Anthoceros punctatus. These properties of strain UCD 311 are consistent with previous observations that protection against oxygen inactivation of nitrogenase is physiologically provided within A. punctatus tissue. Upon deprivation of combined nitrogen, strain UCD 311 clearly differentiates heterocysts and contains typical heterocyst-specific glycolipids; it also makes apparently normal akinetes upon phosphate starvation. Sequence analysis adjacent to the point of the transposon insertion revealed an open reading frame designated devR. Southern analysis established that similar sequences are present in other heterocyst-forming cyanobacteria. devR putatively encodes a protein of 135 amino acids with high similarity to the receiver domains of response regulator proteins characteristics of two-component regulatory systems. On the basis of its size and the absence of other functional domains, DevR is most similar to CheY and Spo0F. Reconstruction of the mutation with an interposon vector confirmed that the transposition event was responsible for the mutant phenotype. The presence of wild-type devR on a plasmid in strain UCD 311 restored the ability to fix nitrogen in air. While devR was not essential for differentiation of akinetes, its presence in trans in Nostoc sp. strain ATCC 29133 stimulated their formation to above normal levels in aging medium. On the basis of RNA analysis, devR is constitutively expressed with respect to the nitrogen source for growth. The devR gene product is essential to the development of mature heterocysts and may be involved in a sensory pathway that is not directly responsive to cellular nitrogen status.

Campbell, E L; Hagen, K D; Cohen, M F; Summers, M L; Meeks, J C

1996-01-01

43

Highly parallel identification of essential genes in cancer cells  

PubMed Central

More complete knowledge of the molecular mechanisms underlying cancer will improve prevention, diagnosis and treatment. Efforts such as The Cancer Genome Atlas are systematically characterizing the structural basis of cancer, by identifying the genomic mutations associated with each cancer type. A powerful complementary approach is to systematically characterize the functional basis of cancer, by identifying the genes essential for growth and related phenotypes in different cancer cells. Such information would be particularly valuable for identifying potential drug targets. Here, we report the development of an efficient, robust approach to perform genome-scale pooled shRNA screens for both positive and negative selection and its application to systematically identify cell essential genes in 12 cancer cell lines. By integrating these functional data with comprehensive genetic analyses of primary human tumors, we identified known and putative oncogenes such as EGFR, KRAS, MYC, BCR-ABL, MYB, CRKL, and CDK4 that are essential for cancer cell proliferation and also altered in human cancers. We further used this approach to identify genes involved in the response of cancer cells to tumoricidal agents and found 4 genes required for the response of CML cells to imatinib treatment: PTPN1, NF1, SMARCB1, and SMARCE1, and 5 regulators of the response to FAS activation, FAS, FADD, CASP8, ARID1A and CBX1. Broad application of this highly parallel genetic screening strategy will not only facilitate the rapid identification of genes that drive the malignant state and its response to therapeutics but will also enable the discovery of genes that participate in any biological process.

Luo, Biao; Cheung, Hiu Wing; Subramanian, Aravind; Sharifnia, Tanaz; Okamoto, Michael; Yang, Xiaoping; Hinkle, Greg; Boehm, Jesse S.; Beroukhim, Rameen; Weir, Barbara A.; Mermel, Craig; Barbie, David A.; Awad, Tarif; Zhou, Xiaochuan; Nguyen, Tuyen; Piqani, Bruno; Li, Cheng; Golub, Todd R.; Meyerson, Matthew; Hacohen, Nir; Hahn, William C.; Lander, Eric S.; Sabatini, David M.; Root, David E.

2008-01-01

44

Essential gene identification and drug target prioritization in Leishmania species.  

PubMed

Leishmaniasis is one of the neglected tropical diseases (NTDs), mainly affecting impoverished communities and having varied ranges of pathogenicity according to the diverse spectrum of clinical manifestations. It is endemic in many countries and poses major challenges to healthcare systems in developing countries. Despite the fact that most of the current mono and combination therapies are found to be failures, clear perception of gene essentiality for parasite survival are now desideratum to identify potential biochemical targets through selection. Here we used the metabolic network of L. major, to perform a comprehensive set of in silico deletion mutants and have systematically recognized a clearly defined set of essential proteins by combining several essential criteria. In this paper we summarize the efforts to prioritize potential drug targets up to a five-fold enrichment compared with a random selection. PMID:24643243

Paul, M L Stanly; Kaur, Amandeep; Geete, Ankit; Sobhia, M Elizabeth

2014-05-01

45

Essential genes in thyroid cancers: focus on fascin  

PubMed Central

Although thyroid cancers are not among common malignancies, they rank as the first prevalent endocrine cancers in human. According to the results of published studies it has been shown the gradual progress from normal to the neoplastic cell in the process of tumor formation is the result of sequential genetic events. Among them we may point the mutations and rearrangements occurred in a group of proto-oncogenes, transcription factors and metastasis elements such as P53, RAS,RET,BRAF, PPAR? and Fascin. In the present article,we reviewed the most important essential genes in thyroid cancers, the role of epithelial mesenchymal transition and Fascin has been highlighted in this paper.

2013-01-01

46

Systematic Identification of Selective Essential Genes in Helicobacter pylori by Genome Prioritization and Allelic Replacement Mutagenesis  

PubMed Central

A comparative genomic approach was used to identify Helicobacter pylori 26695 open reading frames (ORFs) which are conserved in H. pylori J99 but highly diverged in other eubacteria. A survey of selected pathways of central intermediary metabolism was also carried out, and genes with a potentially selective role in H. pylori were identified. Forty-five ORFs identified in these two analyses were screened using a rapid vector-free allelic replacement mutagenesis technique, and 33 were shown to be essential in vitro. Notably, 13 ORFs gave essentiality results which are unexpected in view of their known or proposed functions, and phylogenetic analysis was used to investigate the annotation of 7 such ORFs which are highly diverged. We propose that the products of a number of these H. pylori-specific essential genes may be suitable targets for novel anti-H. pylori therapies.

Chalker, Alison F.; Minehart, Heather W.; Hughes, Nicky J.; Koretke, Kristin K.; Lonetto, Michael A.; Brinkman, Kerry K.; Warren, Patrick V.; Lupas, Andrei; Stanhope, Michael J.; Brown, James R.; Hoffman, Paul S.

2001-01-01

47

High-throughput screen of essential gene modules in Mycobacterium tuberculosis: a bibliometric approach  

PubMed Central

Background Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis). The annotation of functional genome and signaling network in M. tuberculosis are still not systematic. Essential gene modules are a collection of functionally related essential genes in the same signaling or metabolic pathway. The determination of essential genes and essential gene modules at genomic level may be important for better understanding of the physiology and pathology of M. tuberculosis, and also helpful for the development of drugs against this pathogen. The establishment of genomic operon database (DOOR) and the annotation of gene pathways have felicitated the genomic analysis of the essential gene modules of M. tuberculosis. Method Bibliometric approach has been used to perform a High-throughput screen for essential genes of M. tuberculosis strain H37Rv. Ant colony algorithm were used to identify the essential genes in other M. tuberculosis reference strains. Essential gene modules were analyzed by operon database DOOR. The pathways of essential genes were assessed by Biocarta, KEGG, NCI-PID, HumanCyc and Reactome. The function prediction of essential genes was analyzed by Pfam. Results A total approximately 700 essential genes were identified in M. tuberculosis genome. 40% of operons are consisted of two or more essential genes. The essential genes were distributed in 92 pathways in M. tuberculosis. In function prediction, 61.79% of essential genes were categorized into virulence, intermediary metabolism/respiration,cell wall related and lipid metabolism, which are fundamental functions that exist in most bacteria species. Conclusion We have identified the essential genes of M. tuberculosis using bibliometric approach at genomic level. The essential gene modules were further identified and analyzed.

2013-01-01

48

Essential Oil of Eaglewood Tree: a Product of Pathogenesis  

Microsoft Academic Search

The essential oil of eaglewood tree (Aquilaria agallocha Roxb.) has been considered to be a pathological product. An investigation was carried out to study the difference in composition of oils obtained from healthy, naturally infected and artificially inoculated eaglewood using GC and GC\\/MS analyses. This investigation showed a marked difference in the oil compositions among the treatments with regards to

Phatik Tamuli; Paran Boruah; Subhan C. Nath; Piet Leclercq

2005-01-01

49

Coccidioides posadasii Contains a Single 1,3- Glucan Synthase Gene That Appears To Be Essential for Growth  

Microsoft Academic Search

1,3--Glucan synthase is responsible for the synthesis of -glucan, an essential cell wall structural compo- nent in most fungi. We sought to determine whether Coccidioides posadasii possesses genes homologous to known fungal FKS genes that encode the catalytic subunit of 1,3--glucan synthase. A single gene, designated FKS1, was identified, and examination of its predicted protein product showed a high degree

Ellen M. Kellner; Kris I. Orsborn; Erin M. Siegel; M. Alejandra Mandel; Marc J. Orbach; John N. Galgiani

2005-01-01

50

Interdomain lateral gene transfer of an essential ferrochelatase gene in human parasitic nematodes  

PubMed Central

Lateral gene transfer events between bacteria and animals highlight an avenue for evolutionary genomic loss/gain of function. Herein, we report functional lateral gene transfer in animal parasitic nematodes. Members of the Nematoda are heme auxotrophs, lacking the ability to synthesize heme; however, the human filarial parasite Brugia malayi has acquired a bacterial gene encoding ferrochelatase (BmFeCH), the terminal step in heme biosynthesis. BmFeCH, encoded by a 9-exon gene, is a mitochondrial-targeted, functional ferrochelatase based on enzyme assays, complementation, and inhibitor studies. Homologs have been identified in several filariae and a nonfilarial nematode. RNAi and ex vivo inhibitor experiments indicate that BmFeCH is essential for viability, validating it as a potential target for filariasis control.

Wu, Bo; Novelli, Jacopo; Jiang, Daojun; Dailey, Harry A.; Landmann, Frederic; Ford, Louise; Taylor, Mark J.; Carlow, Clotilde K. S.; Kumar, Sanjay; Foster, Jeremy M.; Slatko, Barton E.

2013-01-01

51

A statistical feature of Hurst exponents of essential genes in bacterial genomes.  

PubMed

At present, methods for determining essential genes depend on biochemical experiments. There is therefore a demand for the development of analysis methods and software for identifying essential genes, based on the common features of these genes. In this study, we employed the Hurst exponent as a characteristic parameter and analyzed its distribution among nine bacterial species. We found that most of the significance levels of the Hurst exponents of essential genes were higher than those of the corresponding full-gene-set. Conversely, most of the significance levels of the Hurst exponents of nonessential genes remained unchanged or only increased slightly. Therefore, we propose that this feature represents a restraint for pre- or post-design checking of bacterial essential genes in computer-aided design. PMID:22108754

Liu, Xiao; Wang, Shi-Yuan; Wang, Jia

2012-01-01

52

Hox11 paralogous genes are essential for metanephric kidney induction  

Microsoft Academic Search

The mammalian Hox complex is divided into four linkage groups containing 13 sets of paralogous genes. These paralogous genes have retained functional redundancy during evolution. For this reason, loss of only one or two Hox genes within a paralogous group often results in incompletely penetrant phenotypes which are difficult to interpret by molecular analysis. For example, mice individually mutant for

Deneen M. Wellik; Patrick J. Hawkes; Mario R. Capecchi

2002-01-01

53

Systematic Identification of Novel, Essential Host Genes Affecting Bromovirus RNA Replication  

PubMed Central

Positive-strand RNA virus replication involves viral proteins and cellular proteins at nearly every replication step. Brome mosaic virus (BMV) is a well-established model for dissecting virus-host interactions and is one of very few viruses whose RNA replication, gene expression and encapsidation have been reproduced in the yeast Saccharomyces cerevisiae. Previously, our laboratory identified ?100 non-essential host genes whose loss inhibited or enhanced BMV replication at least 3-fold. However, our isolation of additional BMV-modulating host genes by classical genetics and other results underscore that genes essential for cell growth also contribute to BMV RNA replication at a frequency that may be greater than that of non-essential genes. To systematically identify novel, essential host genes affecting BMV RNA replication, we tested a collection of ?900 yeast strains, each with a single essential gene promoter replaced by a doxycycline-repressible promoter, allowing repression of gene expression by adding doxycycline to the growth medium. Using this strain array of ?81% of essential yeast genes, we identified 24 essential host genes whose depleted expression reproducibly inhibited or enhanced BMV RNA replication. Relevant host genes are involved in ribosome biosynthesis, cell cycle regulation and protein homeostasis, among other cellular processes. BMV 2aPol levels were significantly increased in strains depleted for a heat shock protein (HSF1) or proteasome components (PRE1 and RPT6), suggesting these genes may affect BMV RNA replication by directly or indirectly modulating 2aPol localization, post-translational modification or interacting partners. Investigating the diverse functions of these newly identified essential host genes should advance our understanding of BMV-host interactions and normal cellular pathways, and suggest new modes of virus control.

Gancarz, Brandi L.; Hao, Linhui; He, Qiuling; Newton, Michael A.; Ahlquist, Paul

2011-01-01

54

The Mouse Polyubiquitin Gene Ubb Is Essential for Meiotic Progression? †  

PubMed Central

Ubiquitin is encoded in mice by two polyubiquitin genes, Ubb and Ubc, that are considered to be stress inducible and two constitutively expressed monoubiquitin (Uba) genes. Here we report that targeted disruption of Ubb results in male and female infertility due to failure of germ cells to progress through meiosis I and hypogonadism. In the absence of Ubb, spermatocytes and oocytes arrest during meiotic prophase, before metaphase of the first meiotic division. Although cellular ubiquitin levels are believed to be maintained by a combination of functional redundancy among the four ubiquitin genes, stress inducibility of the two polyubiquitin genes, and ubiquitin recycling by proteasome-associated isopeptidases, our results indicate that ubiquitin is required for and consumed during meiotic progression. The striking similarity of the meiotic phenotype in Ubb?/? germ cells to the sporulation defect in fission yeast (Schizosaccharomyces pombe) lacking a polyubiquitin gene suggests that a meiotic role of the polyubiquitin gene has been conserved throughout eukaryotic evolution.

Ryu, Kwon-Yul; Sinnar, Shamim A.; Reinholdt, Laura G.; Vaccari, Sergio; Hall, Susan; Garcia, Manuel A.; Zaitseva, Tatiana S.; Bouley, Donna M.; Boekelheide, Kim; Handel, Mary Ann; Conti, Marco; Kopito, Ron R.

2008-01-01

55

Characterization of essential genes by topological properties in the perturbation sensitivity network.  

PubMed

Genes that are indispensable for survival are called essential genes. In recent years, the analysis of essential genes has become extremely important for understanding the way a cell functions. With the advent of large-scale gene expression profiling technologies, it is now possible to profile transcriptional changes in the entire genome of Saccharomyces cerevisiae. Notwithstanding the accumulation of gene expression profiling in recent years, only a few studies have used these data to construct the network for S. cerevisiae. In this paper, based on the transcriptional profiling of the S. cerevisiae genome in hundreds of different gene disruptions, the perturbation sensitivity (PS) network is constructed. A scale-free topology with node degree following a power-law distribution is shown in the PS network. Twelve topological properties are used to investigate the characteristics of essential and non-essential genes in the PS network. Most of the properties are found to be statistically discriminative between essential and non-essential genes. In addition, the F-score is used to estimate the essentiality of each property, and the core number demonstrates the highest F-score among all properties. PMID:24802397

Yang, Lei; Wang, Jizhe; Wang, Huiping; Lv, Yingli; Zuo, Yongchun; Jiang, Wei

2014-06-13

56

Comprehensive identification of conditionally essential genes in mycobacteria  

PubMed Central

An increasing number of microbial genomes have been completely sequenced, and the identified genes are categorized based on their homology to genes of known function. However, the function of a large number of genes cannot be determined on this basis alone. Here, we describe a technique, transposon site hybridization (TraSH), which allows rapid functional characterization by identifying the complete set of genes required for growth under different conditions. TraSH combines high-density insertional mutagenesis with microarray mapping of pools of mutants. We have made large pools of independent transposon mutants in mycobacteria by using a mariner-based transposon and efficient phage transduction. By using TraSH, we have defined the set of genes required for growth of Mycobacterium bovis bacillus Calmette–Guérin on minimal but not rich medium. Genes of both known and unknown functions were identified. Of the genes with known functions, nearly all were involved in amino acid biosynthesis. TraSH is a powerful method for categorizing gene function that should be applicable to a variety of microorganisms.

Sassetti, Christopher M.; Boyd, Dana H.; Rubin, Eric J.

2001-01-01

57

Virus production for clinical gene therapy.  

PubMed

Gene therapy is becoming increasingly relevant for the treatment of prominent human diseases. Viral vectors are currently used in more than 50% of the gene therapy clinical trials, most of them aimed at cancer diseases. Clearly, the increasing needs of high-quality viral preparations require the elimination of process bottlenecks, streamlining the development of a viral vector into a real-world clinical tool. Virus production for clinical gene therapy can be a limiting step because many virus generation protocols rely on labor-intensive, bench-scale methods; robust, cost-effective strategies for the delivery of clinical-grade viruses are thus essential for the future of gene therapy. A comprehensive picture of key aspects on the integration of upstream and downstream processing is addressed in this chapter, by describing the case study of recombinant budded baculoviruses for gene therapy; scalable methods are described in detail as well as mandatory characterization techniques for a proper and complete quality assessment of the viral vectors. PMID:19565917

Vicente, Tiago; Peixoto, Cristina; Carrondo, Manuel J T; Alves, Paula M

2009-01-01

58

Gene Targeting Approaches to Complex Genetic Diseases: Atherosclerosis and Essential Hypertension  

Microsoft Academic Search

Gene targeting allows precise, predetermined changes to be made in a chosen gene in the mouse genome. To date, targeting has been used most often for generation of animals completely lacking the product of a gene of interest. The resulting \\

Oliver Smithies; Nobuyo Maeda

1995-01-01

59

Genome-scale identification of conditionally essential genes in E. coli by DNA microarrays  

Microsoft Academic Search

Identifying the genes required for the growth or viability of an organism under a given condition is an important step toward understanding the roles these genes play in the physiology of the organism. Currently, the combination of global transposon mutagenesis with PCR-based mapping of transposon insertion sites is the most common method for determining conditional gene essentiality. In order to

Xin Tonga; John W. Campbell; Gábor Balázsi; Krin A. Kay; Barry L. Wanner; Svetlana Y. Gerdes; Zoltán N. Oltvai

2004-01-01

60

Identification of essential genes in Streptococcus pneumoniae by allelic replacement mutagenesis.  

PubMed

To find potential targets of novel antimicrobial agents, we identified essential genes of Streptococcus pneumoniae using comparative genomics and allelic replacement mutagenesis. We compared the genome of S. pneumoniae R6 with those of Bacillus subtilis, Enterococcus faecalis, Escherichia coli, and Staphylococcus aureus, and selected 693 candidate target genes with > 40% amino acid sequence identity to the corresponding genes in at least two of the other species. The 693 genes were disrupted and 133 were found to be essential for growth. Of these, 32 encoded proteins of unknown function, and we were able to identify orthologues of 22 of these genes by genomic comparisons. The experimental method used in this study is easy to perform, rapid and efficient for identifying essential genes of bacterial pathogens. PMID:15995353

Song, Jae-Hoon; Ko, Kwan Soo; Lee, Ji-Young; Baek, Jin Yang; Oh, Won Sup; Yoon, Ha Sik; Jeong, Jin-Yong; Chun, Jongsik

2005-06-30

61

Towards the prediction of essential genes by integration of network topology, cellular localization and biological process information  

Microsoft Academic Search

Background: The identification of essential genes is important for the understanding of the minimal requirements for cellular life and for practical purposes, such as drug design. However, the experimental techniques for essential genes discovery are labor-intensive and time-consuming. Considering these experimental constraints, a computational approach capable of accurately predicting essential genes would be of great value. We therefore present here

Marcio L. Acencio; Ney Lemke

2009-01-01

62

Expression of Essential B Cell Development Genes in Horses with Common Variable Immunodeficiency  

PubMed Central

Common variable immunodeficiency (CVID) is a heterogeneous disorder of B cell differentiation or function with inadequate antibody production. Our laboratory studies a natural form of CVID in horses characterized by late-onset B cell lymphopenia due to impaired B cell production in the bone marrow. This study was undertaken to assess the status of B cell differentiation in the bone marrow of CVID-affected horses by measuring the expression of genes essential for early B cell commitment and development. Standard RT-PCR revealed that most of the transcription factors and key signaling molecules that directly regulate B cell differentiation in the bone marrow and precede PAX5 are expressed in the affected horses. Yet, the expression of PAX5 and relevant target genes was variable. Quantitative RT-PCR analysis confirmed that the mRNA expression of E2A, PAX5, CD19, and IGHD was significantly reduced in equine CVID patients when compared to healthy horses (p < 0.05). In addition, the PAX5/EBF1 and PAX5/B220 ratios were significantly reduced in CVID patients (p < 0.01). Immunohistochemical analysis confirmed the absence of PAX5-BSAP expression in the bone marrow of affected horses. Our data suggest that B cell development seems to be impaired at the transition between pre-pro-B cells and pro-B cells in equine CVID patients.

Tallmadge, R.L.; Such, K.A.; Miller, K.C.; Matychak, M.B.; Felippe, M.J.B.

2012-01-01

63

Expression of essential B cell development genes in horses with common variable immunodeficiency.  

PubMed

Common variable immunodeficiency (CVID) is a heterogeneous disorder of B cell differentiation or function with inadequate antibody production. Our laboratory studies a natural form of CVID in horses characterized by late-onset B cell lymphopenia due to impaired B cell production in the bone marrow. This study was undertaken to assess the status of B cell differentiation in the bone marrow of CVID-affected horses by measuring the expression of genes essential for early B cell commitment and development. Standard RT-PCR revealed that most of the transcription factors and key signaling molecules that directly regulate B cell differentiation in the bone marrow and precede PAX5 are expressed in the affected horses. Yet, the expression of PAX5 and relevant target genes was variable. Quantitative RT-PCR analysis confirmed that the mRNA expression of E2A, PAX5, CD19, and IGHD was significantly reduced in equine CVID patients when compared to healthy horses (p<0.05). In addition, the PAX5/EBF1 and PAX5/B220 ratios were significantly reduced in CVID patients (p<0.01). Immunohistochemical analysis confirmed the absence of PAX5-BSAP expression in the bone marrow of affected horses. Our data suggest that B cell development seems to be impaired at the transition between pre-pro-B cells and pro-B cells in equine CVID patients. PMID:22464097

Tallmadge, R L; Such, K A; Miller, K C; Matychak, M B; Felippe, M J B

2012-06-01

64

Analysis of Essential Viral Gene Functions after Highly Efficient Adenofection of Cells with Cloned Human Cytomegalovirus Genomes  

PubMed Central

Human cytomegalovirus (HCMV) has a large 240 kb genome that may encode more than 700 gene products with many of them remaining uncharacterized. Mutagenesis of bacterial artificial chromosome (BAC)-cloned CMV genomes has greatly facilitated the analysis of viral gene functions. However, the roles of essential proteins often remain particularly elusive because their investigation requires the cumbersome establishment of suitable complementation systems. Here, we show that HCMV genomes can be introduced into cells with unprecedented efficiency by applying a transfection protocol based on replication-defective, inactivated adenovirus particles (adenofection). Upon adenofection of several permissive cell types with HCMV genomes carrying mutations in essential genes, transfection rates of up to 60% were observed and viral proteins of all kinetic classes were found expressed. This enabled further analyses of the transfected cells by standard biochemical techniques. Remarkably, HCMV genomes lacking elements essential for viral DNA replication, such as the lytic origin of replication, still expressed several late proteins. In conclusion, adenofection allows the study of essential HCMV genes directly in BAC-transfected cells without the need for sophisticated complementation strategies.

Elbasani, Endrit; Gabaev, Ildar; Steinbruck, Lars; Messerle, Martin; Borst, Eva Maria

2014-01-01

65

Angiotensin II type 1 receptor gene polymorphism and essential hypertension in Serbian population  

Microsoft Academic Search

Essential hypertension is considered to be a multifactorial trait resulting from the combined influence of environmental and genetic determinants. Due to the controversial results about the role of the ATR1 gene locus in hypertension and understanding that ethnic origin should be carefully considered in studying the association between gene polymorphism and disease etiology, we investigated the role of A1166C polymorphism

Aleksandra Stankovi?; Maja Živkovic; Sanja Gliši?; Dragan Alavanti?

2003-01-01

66

Relationship between the regulatory region polymorphism of human tissue kallikrein gene and essential hypertension  

Microsoft Academic Search

Ten alleles with length and nucleotide sequence variations were identified in the regulatory region of human tissue kallikrein gene. This present study aimed to study the polymorphisms of the regulatory region of human tissue kallikrein gene of the Chinese and investigate the relationship of the polymorphisms with essential hypertension. A case–control study was conducted in 200 hypertensive and 200 normotensive

H Hua; S Zhou; Y Liu; Z Wang; C Wan; H Li; C Chen; G Li; C Zeng; L Chen; L Chao; J Chao

2005-01-01

67

Identification of Siderophore Biosynthesis Genes Essential for Growth of Aeromonas salmonicida under Iron Limitation Conditions? †  

PubMed Central

Aeromonas salmonicida subsp. salmonicida, the etiological agent of furunculosis in fish, produces a catechol-type siderophore under iron-limiting conditions. In this study, the Fur titration assay (FURTA) was used to identify a cluster of six genes, asbG, asbF, asbD, asbC, asbB, and asbI, encoding proteins similar to components of the siderophore biosynthetic machinery in other bacteria. Reverse transcriptase PCR analyses showed that this cluster consists of four iron-regulated transcriptional units. Mutants with deletions in either asbD (encoding a multidomain nonribosomal peptide synthetase), asbG (encoding a histidine decarboxylase), or asbC (encoding a predicted histamine monooxygenase) did not grow under iron-limiting conditions and did not produce siderophores. Growth of the ?asbG strain under iron starvation conditions was restored by addition of histamine, suggesting that the siderophore in this species could contain a histamine-derived moiety. None of the mutants could grow in the presence of transferrin, indicating that A. salmonicida uses the catechol-type siderophore for removal of iron from transferrin rather than relying on a receptor for this iron-binding protein. All 18 A. salmonicida strains analyzed by DNA probe hybridization were positive in tests for the presence of the asbD gene, and all of them promoted the growth of asbD, asbG, and asbC mutants, suggesting that this siderophore-mediated iron uptake system is conserved among A. salmonicida isolates. This study provides the first description of siderophore biosynthesis genes in this fish pathogen, and the results demonstrate that the asbD, asbG, and asbC genes are necessary for the production of a catecholate siderophore that is essential for the growth of A. salmonicida under iron limitation conditions.

Najimi, Mohsen; Lemos, Manuel L.; Osorio, Carlos R.

2008-01-01

68

Identification of siderophore biosynthesis genes essential for growth of Aeromonas salmonicida under iron limitation conditions.  

PubMed

Aeromonas salmonicida subsp. salmonicida, the etiological agent of furunculosis in fish, produces a catechol-type siderophore under iron-limiting conditions. In this study, the Fur titration assay (FURTA) was used to identify a cluster of six genes, asbG, asbF, asbD, asbC, asbB, and asbI, encoding proteins similar to components of the siderophore biosynthetic machinery in other bacteria. Reverse transcriptase PCR analyses showed that this cluster consists of four iron-regulated transcriptional units. Mutants with deletions in either asbD (encoding a multidomain nonribosomal peptide synthetase), asbG (encoding a histidine decarboxylase), or asbC (encoding a predicted histamine monooxygenase) did not grow under iron-limiting conditions and did not produce siderophores. Growth of the DeltaasbG strain under iron starvation conditions was restored by addition of histamine, suggesting that the siderophore in this species could contain a histamine-derived moiety. None of the mutants could grow in the presence of transferrin, indicating that A. salmonicida uses the catechol-type siderophore for removal of iron from transferrin rather than relying on a receptor for this iron-binding protein. All 18 A. salmonicida strains analyzed by DNA probe hybridization were positive in tests for the presence of the asbD gene, and all of them promoted the growth of asbD, asbG, and asbC mutants, suggesting that this siderophore-mediated iron uptake system is conserved among A. salmonicida isolates. This study provides the first description of siderophore biosynthesis genes in this fish pathogen, and the results demonstrate that the asbD, asbG, and asbC genes are necessary for the production of a catecholate siderophore that is essential for the growth of A. salmonicida under iron limitation conditions. PMID:18296539

Najimi, Mohsen; Lemos, Manuel L; Osorio, Carlos R

2008-04-01

69

Identifying essential genes in bacterial metabolic networks with machine learning methods  

PubMed Central

Background Identifying essential genes in bacteria supports to identify potential drug targets and an understanding of minimal requirements for a synthetic cell. However, experimentally assaying the essentiality of their coding genes is resource intensive and not feasible for all bacterial organisms, in particular if they are infective. Results We developed a machine learning technique to identify essential genes using the experimental data of genome-wide knock-out screens from one bacterial organism to infer essential genes of another related bacterial organism. We used a broad variety of topological features, sequence characteristics and co-expression properties potentially associated with essentiality, such as flux deviations, centrality, codon frequencies of the sequences, co-regulation and phyletic retention. An organism-wise cross-validation on bacterial species yielded reliable results with good accuracies (area under the receiver-operator-curve of 75% - 81%). Finally, it was applied to drug target predictions for Salmonella typhimurium. We compared our predictions to the viability of experimental knock-outs of S. typhimurium and identified 35 enzymes, which are highly relevant to be considered as potential drug targets. Specifically, we detected promising drug targets in the non-mevalonate pathway. Conclusions Using elaborated features characterizing network topology, sequence information and microarray data enables to predict essential genes from a bacterial reference organism to a related query organism without any knowledge about the essentiality of genes of the query organism. In general, such a method is beneficial for inferring drug targets when experimental data about genome-wide knockout screens is not available for the investigated organism.

2010-01-01

70

The Yield of Essential Oils in Melaleuca alternifolia (Myrtaceae) Is Regulated through Transcript Abundance of Genes in the MEP Pathway  

PubMed Central

Medicinal tea tree (Melaleuca alternifolia) leaves contain large amounts of an essential oil, dominated by monoterpenes. Several enzymes of the chloroplastic methylerythritol phosphate (MEP) pathway are hypothesised to act as bottlenecks to the production of monoterpenes. We investigated, whether transcript abundance of genes encoding for enzymes of the MEP pathway were correlated with foliar terpenes in M. alternifolia using a population of 48 individuals that ranged in their oil concentration from 39 -122 mg.g DM?1. Our study shows that most genes in the MEP pathway are co-regulated and that the expression of multiple genes within the MEP pathway is correlated with oil yield. Using multiple regression analysis, variation in expression of MEP pathway genes explained 87% of variation in foliar monoterpene concentrations. The data also suggest that sesquiterpenes in M. alternifolia are synthesised, at least in part, from isopentenyl pyrophosphate originating from the plastid via the MEP pathway.

Webb, Hamish; Lanfear, Robert; Hamill, John; Foley, William J.; Kulheim, Carsten

2013-01-01

71

Identification of Genes and Gene Products Necessary for Bacterial Bioluminescence  

Microsoft Academic Search

Expression of luminescence in Escherichia coli was recently achieved by cloning genes from the marine bacterium Vibrio fischeri. One DNA fragment on a hybrid plasmid encoded regulatory functions and enzymatic activities necessary for light production. We report the results of a genetic analysis to identify the luminescence genes (lux) that reside on this recombinant plasmid. lux gene mutations were generated

Joanne Engebrecht; Michael Silverman

1984-01-01

72

Plasmid integration method: a new tool for analysis of the essentiality and function of genes in S. aureus.  

PubMed

Staphylococcus aureus is a Gram-positive coccus and one of the major causes of community-acquired and hospital-acquired infections. We established the convenient and reliable experimental system for analyzing the essentiality and function of genes, the plasmid integration (PI) method. This method is based on plasmid integration into the genome by single cross-over recombination using a temperature-sensitive shuttle vector, and it was validated using known essential genes, gyrA and mvaD, and non-essential genes, sigB and hla. Then we analyzed 116 S. aureus conserved hypothetical protein genes with the PI method, and identified 28 essential genes. Moreover, applying the PI method, we confirmed the functional redundancy between the S. aureus gene (SA0865) and its ortholog human gene, the NAD kinase gene. These results show that the PI method is a powerful tool for the identification of essential genes and functional analysis by evaluation of complementarity. PMID:22659180

Yamachika, Shinichiro; Onodera, Yoshikuni; Hiramatsu, Keiichi; Takase, Hiroyuki

2012-09-01

73

The snail family gene snai3 is not essential for embryogenesis in mice.  

PubMed

The Snail gene family encodes zinc finger-containing transcriptional repressor proteins. Three members of the Snail gene family have been described in mammals, encoded by the Snai1, Snai2, and Snai3 genes. The function of the Snai1 and Snai2 genes have been studied extensively during both vertebrate embryogenesis and tumor progression and metastasis, and play critically important roles during these processes. However, little is known about the function of the Snai3 gene and protein. We describe here generation and analysis of Snai3 conditional and null mutant mice. We also generated an EYFP-tagged Snai3 null allele that accurately reflects endogenous Snai3 gene expression, with the highest levels of expression detected in thymus and skeletal muscle. Snai3 null mutant homozygous mice are viable and fertile, and exhibit no obvious phenotypic defects. These results demonstrate that Snai3 gene function is not essential for embryogenesis in mice. PMID:23762348

Bradley, Cara K; Norton, Christine R; Chen, Ying; Han, Xianghua; Booth, Carmen J; Yoon, Jeong Kyo; Krebs, Luke T; Gridley, Thomas

2013-01-01

74

A Francisella tularensis DNA clone complements Escherichia coli defective for the production of Era, an essential Ras-like GTP-binding protein  

Microsoft Academic Search

We cloned the era gene of Francisella tularensis from a plasmid library by heterologous genetic complementation of an Escherichia coli mutant conditionally defective for the production of Era, an essential protein for cell growth. Nucleotide sequence analysis indicated that, in F. tularensis, era constitutes a single gene operon. ORFs aspC and mdh encoding aspartate aminotransferase and malate dehydrogenase, respectively, flank

Mohammed Zuber; Timothy A Hoover; Mark T Dertzbaugh; Donald L Court

1997-01-01

75

Expression of TEX101, regulated by ACE, is essential for the production of fertile mouse spermatozoa  

PubMed Central

Formation of spermatozoa of normal shape, number, and motility is insufficient for the male siring of pups. The spermatozoa must be accompanied by sound fertilizing ability. We found that males with disrupted testis-expressed gene 101 (Tex101) produce normal-looking but fertilization-incompetent spermatozoa, which were accompanied by a deficiency of a disintegrin and metallopeptidase domain 3 (ADAM3) on sperm plasma membrane. It was also found that the existence of TEX101 on spermatozoa was regulated by angiotensin-converting enzyme (ACE). The removal of GPI-anchored protein TEX101 by ACE was essential to produce fertile spermatozoa, and the function of ACE was not depending on its well-known peptidase activity. The finding of TEX101 as a unique specific substrate for ACE may provide a potential target for the production of an awaited contraceptive medicine for men.

Fujihara, Yoshitaka; Tokuhiro, Keizo; Muro, Yuko; Kondoh, Gen; Araki, Yoshihiko; Ikawa, Masahito; Okabe, Masaru

2013-01-01

76

Genes of the N-Methylglutamate Pathway Are Essential for Growth of Methylobacterium extorquens DM4 with Monomethylamine.  

PubMed

Monomethylamine (MMA, CH3NH2) can be used as a carbon and nitrogen source by many methylotrophic bacteria. Methylobacterium extorquens DM4 lacks the MMA dehydrogenase encoded by mau genes, which in M. extorquens AM1 is essential for growth on MMA. Identification and characterization of minitransposon mutants with an MMA-dependent phenotype showed that strain DM4 grows with MMA as the sole source of carbon, energy, and nitrogen by the N-methylglutamate (NMG) pathway. Independent mutations were found in a chromosomal region containing the genes gmaS, mgsABC, and mgdABCD for the three enzymes of the pathway, ?-glutamylmethylamide (GMA) synthetase, NMG synthase, and NMG dehydrogenase, respectively. Reverse transcription-PCR confirmed the operonic structure of the two divergent gene clusters mgsABC-gmaS and mgdABCD and their induction during growth with MMA. The genes mgdABCD and mgsABC were found to be essential for utilization of MMA as a carbon and nitrogen source. The gene gmaS was essential for MMA utilization as a carbon source, but residual growth of mutant DM4gmaS growing with succinate and MMA as a nitrogen source was observed. Plasmid copies of gmaS and the gmaS homolog METDI4690, which encodes a protein 39% identical to GMA synthetase, fully restored the ability of mutants DM4gmaS and DM4gmaS?metdi4690 to use MMA as a carbon and nitrogen source. Similarly, chemically synthesized GMA, the product of GMA synthetase, could be used as a nitrogen source for growth in the wild-type strain, as well as in DM4gmaS and DM4gmaS?metdi4690 mutants. The NADH:ubiquinone oxidoreductase respiratory complex component NuoG was also found to be essential for growth with MMA as a carbon source. PMID:24682302

Gruffaz, Christelle; Muller, Emilie E L; Louhichi-Jelail, Yousra; Nelli, Yella R; Guichard, Gilles; Bringel, Françoise

2014-06-01

77

Food production & availability - Essential prerequisites for sustainable food security  

PubMed Central

Food and nutrition security are intimately interconnected, since only a food based approach can help in overcoming malnutrition in an economically and socially sustainable manner. Food production provides the base for food security as it is a key determinant of food availability. This paper deals with different aspects of ensuring high productivity and production without associated ecological harm for ensuring adequate food availability. By mainstreaming ecological considerations in technology development and dissemination, we can enter an era of evergreen revolution and sustainable food and nutrition security. Public policy support is crucial for enabling this.

Swaminathan, M.S.; Bhavani, R.V.

2013-01-01

78

Novel Genetic Variation in Exon 28 of FBN1 Gene Is Associated With Essential Hypertension  

Microsoft Academic Search

BackgroundRecently, fibrillin-1 (FBN1) was reported to play an important role in maintaining the physiological arterial stiffness of essential hypertension (EH). Here, we designed a two-stage case–control study to investigate whether the FBN1 gene harbored any genetic variations associated with EH.MethodsIn stage 1, six candidate single-nucleotide polymorphisms (SNPs) of the FBN1 gene were genotyped and tested in 503 cases and 490

Chong Shen; Xiangfeng Lu; Laiyuan Wang; Shufeng Chen; Yun Li; Xiaoli Liu; Jianxin Li; Jianfeng Huang; Dongfeng Gu

2011-01-01

79

Construction of a Bacterial Cell that Contains Only the Set of Essential Genes Necessary to Impart Life.  

National Technical Information Service (NTIS)

Work has continued on the Top Down approach to genome minimization. We have used the Essential (E), Non-essential (N), and Impaired (I) gene categories to make steady progress with gene and gene cluster deletions. To date, we have removed approximately 23...

A. Yee C. Hutchison H. Smith J. Glass

2013-01-01

80

Construction of a Bacterial Cell that Contains Only the Set of Essential Genes Necessary to Impart Life.  

National Technical Information Service (NTIS)

We have made significant progress on all fronts of the project. On the Top Down approach to genome minimization, we have used the Essential (E), Non-essential (N), and Impaired (I) gene categories to make steady progress with gene and gene cluster deletio...

A. Yee C. Hutchison H. Smith J. Glass

2013-01-01

81

Fuzzy measures on the Gene Ontology for gene product similarity.  

PubMed

One of the most important objects in bioinformatics is a gene product (protein or RNA). For many gene products, functional information is summarized in a set of Gene Ontology (GO) annotations. For these genes, it is reasonable to include similarity measures based on the terms found in the GO or other taxonomy. In this paper, we introduce several novel measures for computing the similarity of two gene products annotated with GO terms. The fuzzy measure similarity (FMS) has the advantage that it takes into consideration the context of both complete sets of annotation terms when computing the similarity between two gene products. When the two gene products are not annotated by common taxonomy terms, we propose a method that avoids a zero similarity result. To account for the variations in the annotation reliability, we propose a similarity measure based on the Choquet integral. These similarity measures provide extra tools for the biologist in search of functional information for gene products. The initial testing on a group of 194 sequences representing three proteins families shows a higher correlation of the FMS and Choquet similarities to the BLAST sequence similarities than the traditional similarity measures such as pairwise average or pairwise maximum. PMID:17048464

Popescu, Mihail; Keller, James M; Mitchell, Joyce A

2006-01-01

82

Experimental and Computational Assessment of Conditionally Essential Genes in Escherichia coli?  

PubMed Central

Genome-wide gene essentiality data sets are becoming available for Escherichia coli, but these data sets have yet to be analyzed in the context of a genome scale model. Here, we present an integrative model-driven analysis of the Keio E. coli mutant collection screened in this study on glycerol-supplemented minimal medium. Out of 3,888 single-deletion mutants tested, 119 mutants were unable to grow on glycerol minimal medium. These conditionally essential genes were then evaluated using a genome scale metabolic and transcriptional-regulatory model of E. coli, and it was found that the model made the correct prediction in ?91% of the cases. The discrepancies between model predictions and experimental results were analyzed in detail to indicate where model improvements could be made or where the current literature lacks an explanation for the observed phenotypes. The identified set of essential genes and their model-based analysis indicates that our current understanding of the roles these essential genes play is relatively clear and complete. Furthermore, by analyzing the data set in terms of metabolic subsystems across multiple genomes, we can project which metabolic pathways are likely to play equally important roles in other organisms. Overall, this work establishes a paradigm that will drive model enhancement while simultaneously generating hypotheses that will ultimately lead to a better understanding of the organism.

Joyce, Andrew R.; Reed, Jennifer L.; White, Aprilfawn; Edwards, Robert; Osterman, Andrei; Baba, Tomoya; Mori, Hirotada; Lesely, Scott A.; Palsson, Bernhard ?.; Agarwalla, Sanjay

2006-01-01

83

Mutational accessibility of essential genes on chromosome I(left) in Caenorhabditis elegans.  

PubMed

We have analyzed a region of approximately 5.4 million base pairs for mutations, which under standard laboratory conditions result in developmental arrest, sterility, or maternal-effect lethality in Caenorhabditis elegans. Lethal mutations were isolated, maintained, and genetically manipulated as homozygotes using sDp2--a duplication of the left half of chromosome I. All of the lethals and rearrangements used in this analysis were balanced by sDp2. Relatively low doses of mutagen, (approximately 15 mM ethylmethane sulfate; EMS), were used so as to limit the occurrence of second-site mutations, thus increasing the probability of recovering single nucleotide substitutions. Treatment of over 32,400 marked chromosomes resulted in 486 analyzed mutations. In this paper, we add 133 previously unidentified let genes, isolated in the EMS screens, and one let gene identified by a gamma-ray induced mutation, to our collection of 103 essential genes. We also recovered lethal alleles of genes for which visible mutants already existed. In total, eight deficiencies and alleles of 237 essential genes were identified. Eighty-nine of the previously unidentified let genes are represented by more than one lethal allele. Statistical analysis indicates a minimum estimate of 400 essential genes in the region of chromosome I balanced by sDp2. This region occupies approximately half of chromosome I, and contains over 1135 protein-coding genes predicted from the genomic sequence data. Thus, approximately one-third of the predicted genes are estimated to be essential. Of these approximately 60% are represented by lethal alleles. Less than 2% of the lethal-bearing strains recovered in our analysis, including the eight genetically definable deficiencies, carried more than one lethal mutation. Several screens were used to recover mutations for this analysis. Because all the mutations were isolated using the same balancer, under similar screening conditions, it was possible to compare intervals within the sDp2 region with each other. The fraction of essential genes that present relatively large targets for EMS was highest within the central cluster (dpy-5 to unc-13). PMID:10778742

Johnsen, R C; Jones, S J; Rose, A M

2000-03-01

84

The essential helicase gene RAD3 suppresses short-sequence recombination in Saccharomyces cerevisiae.  

PubMed Central

We have isolated an allele of the essential DNA repair and transcription gene RAD3 that relaxes the restriction against recombination between short DNA sequences in Saccharomyces cerevisiae. Double-strand break repair and gene replacement events requiring recombination between short identical or mismatched sequences were stimulated in the rad3-G595R mutant cells. We also observed an increase in the physical stability of double-strand breaks in the rad3-G595R mutant cells. These results suggest that the RAD3 gene suppresses recombination involving short homologous sequences by promoting the degradation of the ends of broken DNA molecules.

Bailis, A M; Maines, S; Negritto, M T

1995-01-01

85

The essential helicase gene RAD3 suppresses short-sequence recombination in Saccharomyces cerevisiae.  

PubMed

We have isolated an allele of the essential DNA repair and transcription gene RAD3 that relaxes the restriction against recombination between short DNA sequences in Saccharomyces cerevisiae. Double-strand break repair and gene replacement events requiring recombination between short identical or mismatched sequences were stimulated in the rad3-G595R mutant cells. We also observed an increase in the physical stability of double-strand breaks in the rad3-G595R mutant cells. These results suggest that the RAD3 gene suppresses recombination involving short homologous sequences by promoting the degradation of the ends of broken DNA molecules. PMID:7623796

Bailis, A M; Maines, S; Negritto, M T

1995-08-01

86

Functional study of genes essential for autogamy and nuclear reorganization in Paramecium.  

PubMed

Like all ciliates, Paramecium tetraurelia is a unicellular eukaryote that harbors two kinds of nuclei within its cytoplasm. At each sexual cycle, a new somatic macronucleus (MAC) develops from the germ line micronucleus (MIC) through a sequence of complex events, which includes meiosis, karyogamy, and assembly of the MAC genome from MIC sequences. The latter process involves developmentally programmed genome rearrangements controlled by noncoding RNAs and a specialized RNA interference machinery. We describe our first attempts to identify genes and biological processes that contribute to the progression of the sexual cycle. Given the high percentage of unknown genes annotated in the P. tetraurelia genome, we applied a global strategy to monitor gene expression profiles during autogamy, a self-fertilization process. We focused this pilot study on the genes carried by the largest somatic chromosome and designed dedicated DNA arrays covering 484 genes from this chromosome (1.2% of all genes annotated in the genome). Transcriptome analysis revealed four major patterns of gene expression, including two successive waves of gene induction. Functional analysis of 15 upregulated genes revealed four that are essential for vegetative growth, one of which is involved in the maintenance of MAC integrity and another in cell division or membrane trafficking. Two additional genes, encoding a MIC-specific protein and a putative RNA helicase localizing to the old and then to the new MAC, are specifically required during sexual processes. Our work provides a proof of principle that genes essential for meiosis and nuclear reorganization can be uncovered following genome-wide transcriptome analysis. PMID:21257794

Nowak, Jacek K; Gromadka, Robert; Juszczuk, Marek; Jerka-Dziadosz, Maria; Maliszewska, Kamila; Mucchielli, Marie-Hélène; Gout, Jean-François; Arnaiz, Olivier; Agier, Nicolas; Tang, Thomas; Aggerbeck, Lawrence P; Cohen, Jean; Delacroix, Hervé; Sperling, Linda; Herbert, Christopher J; Zagulski, Marek; Bétermier, Mireille

2011-03-01

87

Functional Study of Genes Essential for Autogamy and Nuclear Reorganization in Paramecium?§  

PubMed Central

Like all ciliates, Paramecium tetraurelia is a unicellular eukaryote that harbors two kinds of nuclei within its cytoplasm. At each sexual cycle, a new somatic macronucleus (MAC) develops from the germ line micronucleus (MIC) through a sequence of complex events, which includes meiosis, karyogamy, and assembly of the MAC genome from MIC sequences. The latter process involves developmentally programmed genome rearrangements controlled by noncoding RNAs and a specialized RNA interference machinery. We describe our first attempts to identify genes and biological processes that contribute to the progression of the sexual cycle. Given the high percentage of unknown genes annotated in the P. tetraurelia genome, we applied a global strategy to monitor gene expression profiles during autogamy, a self-fertilization process. We focused this pilot study on the genes carried by the largest somatic chromosome and designed dedicated DNA arrays covering 484 genes from this chromosome (1.2% of all genes annotated in the genome). Transcriptome analysis revealed four major patterns of gene expression, including two successive waves of gene induction. Functional analysis of 15 upregulated genes revealed four that are essential for vegetative growth, one of which is involved in the maintenance of MAC integrity and another in cell division or membrane trafficking. Two additional genes, encoding a MIC-specific protein and a putative RNA helicase localizing to the old and then to the new MAC, are specifically required during sexual processes. Our work provides a proof of principle that genes essential for meiosis and nuclear reorganization can be uncovered following genome-wide transcriptome analysis.

Nowak, Jacek K.; Gromadka, Robert; Juszczuk, Marek; Jerka-Dziadosz, Maria; Maliszewska, Kamila; Mucchielli, Marie-Helene; Gout, Jean-Francois; Arnaiz, Olivier; Agier, Nicolas; Tang, Thomas; Aggerbeck, Lawrence P.; Cohen, Jean; Delacroix, Herve; Sperling, Linda; Herbert, Christopher J.; Zagulski, Marek; Betermier, Mireille

2011-01-01

88

Genes Found Essential in Other Mycoplasmas Are Dispensable in Mycoplasma bovis  

PubMed Central

Mycoplasmas are regarded to be useful models for studying the minimum genetic complement required for independent survival of an organism. Mycoplasma bovis is a globally distributed pathogen causing pneumonia, mastitis, arthritis, otitis media and reproductive tract disease, and genome sequences of three strains, the type strain PG45 and two strains isolated in China, have been published. In this study, several Tn4001 based transposon constructs were generated and used to create a M. bovis PG45 insertional mutant library. Direct genome sequencing of 319 independent insertions detected disruptions in 129 genes in M. bovis, 48 of which had homologues in Mycoplasma mycoides subspecies mycoides SC and 99 of which had homologues in Mycoplasma agalactiae. Sixteen genes found to be essential in previous studies on other mycoplasma species were found to be dispensable. Five of these genes have previously been predicted to be part of the core set of 153 essential genes in mycoplasmas. Thus this study has extended the list of non-essential genes of mycoplasmas from that previously generated by studies in other species.

Sharma, Shukriti; Markham, Philip F.; Browning, Glenn F.

2014-01-01

89

Genes found essential in other mycoplasmas are dispensable in Mycoplasma bovis.  

PubMed

Mycoplasmas are regarded to be useful models for studying the minimum genetic complement required for independent survival of an organism. Mycoplasma bovis is a globally distributed pathogen causing pneumonia, mastitis, arthritis, otitis media and reproductive tract disease, and genome sequences of three strains, the type strain PG45 and two strains isolated in China, have been published. In this study, several Tn4001 based transposon constructs were generated and used to create a M. bovis PG45 insertional mutant library. Direct genome sequencing of 319 independent insertions detected disruptions in 129 genes in M. bovis, 48 of which had homologues in Mycoplasma mycoides subspecies mycoides SC and 99 of which had homologues in Mycoplasma agalactiae. Sixteen genes found to be essential in previous studies on other mycoplasma species were found to be dispensable. Five of these genes have previously been predicted to be part of the core set of 153 essential genes in mycoplasmas. Thus this study has extended the list of non-essential genes of mycoplasmas from that previously generated by studies in other species. PMID:24897538

Sharma, Shukriti; Markham, Philip F; Browning, Glenn F

2014-01-01

90

Identifying essential genes in mouse development via an ENU-based forward genetic approach.  

PubMed

The completion of the human and mouse genome projects at the beginning of the past decade represented a very important step forward in our pursuit of a comprehensive understanding of the genetic control of mammalian development. Nevertheless, genetic analyses of mutant phenotypes are still needed to understand the function of individual genes. The genotype-based approaches, including gene-trapping and gene-targeting, promise a mutant embryonic stem (ES) cell resource for all the genes in mouse genome; however, the phenotypic consequences of these mutations will not be addressed until mutant mice are derived from these ES cells, which is not trivial. An efficient and non-biased, N-ethyl-N-nitrosourea (ENU)-based forward genetic approach in mouse provides a unique tool for the identification of genes essential for development and adult physiology. We have had great success in identifying genes essential for morphogenesis and early patterning of mouse via this approach. Combined with complete genome information and numerous genetic resources available, ENU-based mutagenesis has become a powerful tool in deciphering gene functions. PMID:24318816

Liu, Aimin; Eggenschwiler, Jonathan

2014-01-01

91

Functional requirements for bacteriophage growth: Gene essentiality and expression in Mycobacteriophage Giles  

PubMed Central

Summary Bacteriophages represent a majority of all life forms, and the vast, dynamic population with early origins is reflected in their enormous genetic diversity. A large number of bacteriophage genomes have been sequenced. They are replete with novel genes without known relatives. We know little about their functions, which genes are required for lytic growth, and how they are expressed. Furthermore, the diversity is such that even genes with required functions – such as virion proteins and repressors – cannot always be recognized. Here we describe a functional genomic dissection of mycobacteriophage Giles, in which the virion proteins are identified, genes required for lytic growth are determined, the repressor is identified, and the transcription patterns determined. We find that although all of the predicted phage genes are expressed either in lysogeny or in lytic growth, 45% of the predicted genes are non-essential for lytic growth. We also describe genes required for DNA replication, show that recombination is required for lytic growth, and that Giles encodes a novel repressor. RNAseq analysis reveals abundant expression of a small non-coding RNA in a lysogen and in late lytic growth, although it is non-essential for lytic growth and does not alter lysogeny.

Dedrick, Rebekah M.; Marinelli, Laura J.; Newton, Gerald L.; Pogliano, Kit; Pogliano, Joseph; Hatfull, Graham F.

2013-01-01

92

whmD is an essential mycobacterial gene required for proper septation and cell division  

PubMed Central

A study of potential mycobacterial regulatory genes led to the isolation of the Mycobacterium smegmatis whmD gene, which encodes a homologue of WhiB, a Streptomyces coelicolor protein required for sporulation. Unlike its Streptomyces homologue, WhmD is essential in M. smegmatis. The whmD gene could be disrupted only in the presence of a plasmid supplying whmD in trans. A plasmid that allowed chemically regulated expression of the WhmD protein was used to generate a conditional whmD mutant. On withdrawal of the inducer, the conditional whmD mutant exhibited irreversible, filamentous, branched growth with diminished septum formation and aberrant septal placement, whereas WhmD overexpression resulted in growth retardation and hyperseptation. Nucleic acid synthesis and levels of the essential cell division protein FtsZ were unaltered by WhmD deficiency. Together, these phenotypes indicate a role for WhmD in mycobacterial septum formation and cell division.

Gomez, James E.; Bishai, William R.

2000-01-01

93

Coccidioides posadasii contains a single 1,3-beta-glucan synthase gene that appears to be essential for growth.  

PubMed

1,3-beta-Glucan synthase is responsible for the synthesis of beta-glucan, an essential cell wall structural component in most fungi. We sought to determine whether Coccidioides posadasii possesses genes homologous to known fungal FKS genes that encode the catalytic subunit of 1,3-beta-glucan synthase. A single gene, designated FKS1, was identified, and examination of its predicted protein product showed a high degree of conservation with Fks proteins from other filamentous fungi. FKS1 is expressed at similar levels in mycelia and early spherulating cultures, and expression decreases as the spherules mature. We used Agrobacterium-mediated transformation to create strains that harbor DeltaFKS1::hygB, a null allele of FKS1, and hypothesize that Fks1p function is essential, due to our inability to purify this allele away from a complementing wild-type FKS1 allele in a heterokaryotic strain. The heterokaryon appears normal with respect to growth rate and arthroconidium production; however, microscopic examination of strains with DeltaFKS1::hygB alleles revealed abnormal swelling of hyphal elements. PMID:15643067

Kellner, Ellen M; Orsborn, Kris I; Siegel, Erin M; Mandel, M Alejandra; Orbach, Marc J; Galgiani, John N

2005-01-01

94

Selection and production of oregano rich in essential oil and carvacrol  

Microsoft Academic Search

There is an increasing interest in oregano essential oil and its component carvacrol for the use as a feed additive with antimicrobial properties, enhancing the health of poultry and pigs. This chapter describes the initial agronomic attempts (in the years 2001-2004) to acquire and develop Origanum strains rich in essential oil and carvacrol for optimal field production (of crop biomass

Mheen van der H. J. C. J

2005-01-01

95

Effective identification of essential proteins based on priori knowledge, network topology and gene expressions.  

PubMed

Identification of essential proteins is very important for understanding the minimal requirements for cellular life and also necessary for a series of practical applications, such as drug design. With the advances in high throughput technologies, a large number of protein-protein interactions are available, which makes it possible to detect proteins' essentialities from the network level. Considering that most species already have a number of known essential proteins, we proposed a new priori knowledge-based scheme to discover new essential proteins from protein interaction networks. Based on the new scheme, two essential protein discovery algorithms, CPPK and CEPPK, were developed. CPPK predicts new essential proteins based on network topology and CEPPK detects new essential proteins by integrating network topology and gene expressions. The performances of CPPK and CEPPK were validated based on the protein interaction network of Saccharomyces cerevisiae. The experimental results showed that the priori knowledge of known essential proteins was effective for improving the predicted precision. The predicted precisions of CPPK and CEPPK clearly exceeded that of the other 10 previously proposed essential protein discovery methods: Degree Centrality (DC), Betweenness Centrality (BC), Closeness Centrality (CC), Subgraph Centrality (SC), Eigenvector Centrality (EC), Information Centrality (IC), Bottle Neck (BN), Density of Maximum Neighborhood Component (DMNC), Local Average Connectivity-based method (LAC), and Network Centrality (NC). Especially, CPPK achieved 40% improvement in precision over BC, CC, SC, EC, and BN, and CEPPK performed even better. CEPPK was also compared to four other methods (EPC, ORFL, PeC, and CoEWC) which were not node centralities and CEPPK was showed to achieve the best results. PMID:24565748

Li, Min; Zheng, Ruiqing; Zhang, Hanhui; Wang, Jianxin; Pan, Yi

2014-06-01

96

Production of essential oils and flavours in plant cell and tissue cultures. A review  

Microsoft Academic Search

The production of essential oils and flavours by plant cell and tissue cultures is reviewed, including the biotransformation of added precursors. Methods which have been employed to increase secondary metabolism are discussed.

Th. Mulder-Krieger; R. Verpoorte; A. Baerheim Svendsen; J. J. C. Scheffer

1988-01-01

97

Arabidopsis genes essential for seedling viability: isolation of insertional mutants and molecular cloning.  

PubMed Central

We have undertaken a large-scale genetic screen to identify genes with a seedling-lethal mutant phenotype. From screening approximately 38,000 insertional mutant lines, we identified >500 seedling-lethal mutants, completed cosegregation analysis of the insertion and the lethal phenotype for >200 mutants, molecularly characterized 54 mutants, and provided a detailed description for 22 of them. Most of the seedling-lethal mutants seem to affect chloroplast function because they display altered pigmentation and affect genes encoding proteins predicted to have chloroplast localization. Although a high level of functional redundancy in Arabidopsis might be expected because 65% of genes are members of gene families, we found that 41% of the essential genes found in this study are members of Arabidopsis gene families. In addition, we isolated several interesting classes of mutants and genes. We found three mutants in the recently discovered nonmevalonate isoprenoid biosynthetic pathway and mutants disrupting genes similar to Tic40 and tatC, which are likely to be involved in chloroplast protein translocation. Finally, we directly compared T-DNA and Ac/Ds transposon mutagenesis methods in Arabidopsis on a genome scale. In each population, we found only about one-third of the insertion mutations cosegregated with a mutant phenotype.

Budziszewski, G J; Lewis, S P; Glover, L W; Reineke, J; Jones, G; Ziemnik, L S; Lonowski, J; Nyfeler, B; Aux, G; Zhou, Q; McElver, J; Patton, D A; Martienssen, R; Grossniklaus, U; Ma, H; Law, M; Levin, J Z

2001-01-01

98

COLT-Cancer: functional genetic screening resource for essential genes in human cancer cell lines  

PubMed Central

Genome-wide pooled shRNA screens enable global identification of the genes essential for cancer cell survival and proliferation and provide a ‘functional genetic’ map of human cancer to complement genomic studies. Using a lentiviral shRNA library targeting approximately 16?000 human genes and a newly developed scoring approach, we identified essential gene profiles in more than 70 breast, pancreatic and ovarian cancer cell lines. We developed a web-accessible database system for capturing information from each step in our standardized screening pipeline and a gene-centric search tool for exploring shRNA activities within a given cell line or across multiple cell lines. The database consists of a laboratory information and management system for tracking each step of a pooled shRNA screen as well as a web interface for querying and visualization of shRNA and gene-level performance across multiple cancer cell lines. COLT-Cancer Version 1.0 is currently accessible at http://colt.ccbr.utoronto.ca/cancer.

Koh, Judice L. Y.; Brown, Kevin R.; Sayad, Azin; Kasimer, Dahlia; Ketela, Troy; Moffat, Jason

2012-01-01

99

An essential gene of Saccharomyces cerevisiae coding for an actin-related protein.  

PubMed Central

Actin filaments provide the internal scaffold of eukaryotic cells; they are involved in maintenance of cell shape, cytokinesis, organelle movement, and cell motility. The major component of these filaments, actin, is one of the most well-conserved eukaryotic proteins. Recently genes more distantly related to the conventional actins were cloned from several organisms. In the budding yeast, Saccharomyces cerevisiae, one conventional actin gene, ACT1 (coding for the filament actin), and a so-called actin-like gene, ACT2 (of unknown function), have so far been identified. We report here the discovery of a third member of the actin gene family from this organism, which we named ACT3. The latter gene is essential for viability and codes for a putative polypeptide, Act3, of 489 amino acids (M(r) = 54,831). The deduced amino acid sequence of Act3 is less related to conventional actins than is the deduced amino acid sequence of Act2, mainly because of three unique hydrophilic [corrected] segments. These segments are found inserted into a part of the sequence corresponding to a surface loop of the known three-dimensional structure of the actin molecule. According to sequence comparison, the basal core structure of conventional actin may well be conserved in Act3. Our findings demonstrate that, unexpectedly, there exist three members of the diverse actin protein family in budding yeast that obviously provide different essential functions for survival. Images

Harata, M; Karwan, A; Wintersberger, U

1994-01-01

100

The p53-induced Gene Ei24 Is an Essential Component of the Basal Autophagy Pathway*  

PubMed Central

Ei24 is a DNA damage response gene involved in growth suppression and apoptosis. The physiological function of Ei24, however, is poorly understood. Here we generated conditional knock-out mice of Ei24 and demonstrated that EI24 is an essential component of the basal autophagy pathway. Mice with neural-specific Ei24 deficiency develop age-dependent neurological abnormalities caused by massive axon degeneration and extensive neuron loss in brain and spinal cord. Notably, ablation of Ei24 leads to vacuolated oligodendroglial cells and demyelination of axons. Liver-specific depletion of Ei24 causes severe hepatomegaly with hepatocyte hypertrophy. Ei24 deficiency impairs autophagic flux, leading to accumulation of LC3, p62 aggregates, and ubiquitin-positive inclusions. Our study indicates that Ei24 is an essential autophagy gene and plays an important role in clearance of aggregate-prone proteins in neurons and hepatocytes.

Zhao, Yan G.; Zhao, Hongyu; Miao, Lin; Wang, Li; Sun, Fei; Zhang, Hong

2012-01-01

101

A P-element insertion screen identified mutations in 455 novel essential genes in Drosophila.  

PubMed Central

With the completion of the nucleotide sequences of several complex eukaryotic genomes, tens of thousands of genes have been predicted. However, this information has to be correlated with the functions of those genes to enhance our understanding of biology and to improve human health care. The Drosophila transposon P-element-induced mutations are very useful for directly connecting gene products to their biological function. We designed an efficient transposon P-element-mediated gene disruption procedure and performed genetic screening for single P-element insertion mutations, enabling us to recover 2500 lethal mutations. Among these, 2355 are second chromosome mutations. Sequences flanking >2300 insertions that identify 850 different genes or ESTs (783 genes on the second chromosome and 67 genes on the third chromosome) have been determined. Among these, 455 correspond to genes for which no lethal mutation has yet been reported. The Drosophila genome is thought to contain approximately 3600 vital genes; 1400 are localized on the second chromosome. Our mutation collection represents approximately 56% of the second chromosome vital genes and approximately 24% of the total vital Drosophila genes.

Oh, Su-Wan; Kingsley, Tracy; Shin, Hyun-hee; Zheng, Zhiyu; Chen, Hua-Wei; Chen, Xiu; Wang, Hong; Ruan, Peizheng; Moody, Michelle; Hou, Steven X

2003-01-01

102

The Transcription Factor Gene Nfib Is Essential for both Lung Maturation and Brain Development  

Microsoft Academic Search

The phylogenetically conserved nuclear factor I (NFI) gene family encodes site-specific transcription factors essential for the development of a number of organ systems. We showed previously that Nfia-deficient mice exhibit agenesis of the corpus callosum and other forebrain defects, whereas Nfic-deficient mice have agenesis of molar tooth roots and severe incisor defects. Here we show that Nfib-deficient mice possess unique

George Steele-Perkins; C. Plachez; K. G. Butz; G. Yang; C. J. Bachurski; S. L. Kinsman; E. D. Litwack; L. J. Richards; R. M. Gronostajski

2005-01-01

103

Identification and Characterization of Helicobacter pylori Genes Essential for Gastric Colonization  

PubMed Central

Helicobacter pylori causes one of the most common, chronic bacterial infections and is a primary cause of severe gastric disorders. To unravel the bacterial factors necessary for the process of gastric colonization and pathogenesis, signature tagged mutagenesis (STM) was adapted to H. pylori. The Mongolian gerbil (Meriones unguiculatus) was used as model system to screen a set of 960 STM mutants. This resulted in 47 H. pylori genes, assigned to 9 different functional categories, representing a set of biological functions absolutely essential for gastric colonization, as verified and quantified for many mutants by competition experiments. Identification of previously known colonization factors, such as the urease and motility functions validated this method, but also novel and several hypothetical genes were found. Interestingly, a secreted collagenase, encoded by hp0169, could be identified and functionally verified as a new essential virulence factor for H. pylori stomach colonization. Furthermore, comB4, encoding a putative ATPase being part of a DNA transformation-associated type IV transport system of H. pylori was found to be absolutely essential for colonization, but natural transformation competence was apparently not the essential function. Thus, this first systematic STM application identified a set of previously unknown H. pylori colonization factors and may help to potentiate the development of novel therapies against gastric Helicobacter infections.

Kavermann, Holger; Burns, Brendan P.; Angermuller, Katrin; Odenbreit, Stefan; Fischer, Wolfgang; Melchers, Klaus; Haas, Rainer

2003-01-01

104

FKBP14 is an essential gene that regulates Presenilin protein levels and Notch signaling in Drosophila.  

PubMed

Presenilins were identified as causative factors in familial Alzheimer's disease and also play an essential role in Notch signaling during development. We previously identified FKBP14, a member of the family of FK506-binding proteins (FKBPs), as a modifier of Presenilin in Drosophila. FKBPs are highly conserved peptidyl-prolyl cis-trans isomerases that play integral roles in protein folding, assembly and trafficking. Although FKBPs have been implicated in a broad range of biological processes, they are non-essential in yeast and their role in the development of multicellular organisms remains unclear. We show that FKBP14 is an essential gene in Drosophila and that loss of FKBP14 gives rise to specific defects in eye, bristle and wing development. FKBP14 mutants genetically interact with components of the Notch pathway, indicating that these phenotypes are associated, at least in part, with dysregulation of Notch signaling. We show that whereas Notch trafficking to the membrane is unaffected in FKBP14 mutants, levels of Notch target genes are reduced, suggesting that FKBP14 acts downstream of Notch activation at the membrane. Consistent with this model, we find that Presenilin protein levels and ?-secretase activity are reduced in FKBP14 null mutants. Altogether, our data demonstrate that FKBP14 plays an essential role in development, one aspect of which includes regulating members of the Notch signaling pathway. PMID:23318643

van de Hoef, Diana L; Bonner, Julia M; Boulianne, Gabrielle L

2013-02-01

105

The organ-specific expression of terpene synthase genes contributes to the terpene hydrocarbon composition of chamomile essential oils  

PubMed Central

Background The essential oil of chamomile, one of the oldest and agronomically most important medicinal plant species in Europe, has significant antiphlogistic, spasmolytic and antimicrobial activities. It is rich in chamazulene, a pharmaceutically active compound spontaneously formed during steam distillation from the sesquiterpene lactone matricine. Chamomile oil also contains sesquiterpene alcohols and hydrocarbons which are produced by the action of terpene synthases (TPS), the key enzymes in constructing terpene carbon skeletons. Results Here, we present the identification and characterization of five TPS enzymes contributing to terpene biosynthesis in chamomile (Matricaria recutita). Four of these enzymes were exclusively expressed in above-ground organs and produced the common terpene hydrocarbons (?)-(E)-?-caryophyllene (MrTPS1), (+)-germacrene A (MrTPS3), (E)-?-ocimene (MrTPS4) and (?)-germacrene D (MrTPS5). A fifth TPS, the multiproduct enzyme MrTPS2, was mainly expressed in roots and formed several Asteraceae-specific tricyclic sesquiterpenes with (?)-?-isocomene being the major product. The TPS transcript accumulation patterns in different organs of chamomile were consistent with the abundance of the corresponding TPS products isolated from these organs suggesting that the spatial regulation of TPS gene expression qualitatively contribute to terpene composition. Conclusions The terpene synthases characterized in this study are involved in the organ-specific formation of essential oils in chamomile. While the products of MrTPS1, MrTPS2, MrTPS4 and MrTPS5 accumulate in the oils without further chemical alterations, (+)-germacrene A produced by MrTPS3 accumulates only in trace amounts, indicating that it is converted into another compound like matricine. Thus, MrTPS3, but also the other TPS genes, are good markers for further breeding of chamomile cultivars rich in pharmaceutically active essential oils.

2012-01-01

106

Plasmid selection in Escherichia coli using an endogenous essential gene marker  

Microsoft Academic Search

BACKGROUND: Antibiotic resistance genes are widely used for selection of recombinant bacteria, but their use risks contributing to the spread of antibiotic resistance. In particular, the practice is inappropriate for some intrinsically resistant bacteria and in vaccine production, and costly for industrial scale production. Non-antibiotic systems are available, but require mutant host strains, defined media or expensive reagents. An unexplored

Shan Goh; Liam Good

2008-01-01

107

Angiotensin II type 1 receptor gene polymorphism and essential hypertension in Serbian population.  

PubMed

Essential hypertension is considered to be a multifactorial trait resulting from the combined influence of environmental and genetic determinants. Due to the controversial results about the role of the ATR1 gene locus in hypertension and understanding that ethnic origin should be carefully considered in studying the association between gene polymorphism and disease etiology, we investigated the role of A1166C polymorphism in Serbian hypertensives. A total of 298 subjects, 100 hypertensive and 198 normotensive, age- and sex-matched controls, were included in this study. All subjects were genotyped for the A1166C polymorphism in ATR1 gene using allele-specific PCR-based technique. There were significant differences in both allele and genotype frequencies between hypertensive and normotensive male subjects (p<0.05). There is significant association between hypertension and CC genotype (CC vs. AC+AA OR=2.56, p=0.04) in the males only. These results suggest that a genetic variant of the ATR1 gene locus influences the risk of essential hypertension in the sex-specific manner in the Serbian population. PMID:12482634

Stankovi?, Aleksandra; Zivkovic, Maja; Glisi?, Sanja; Alavanti?, Dragan

2003-01-01

108

Reversible suppression of an essential gene in adult mice using transgenic RNA interference  

PubMed Central

RNAi has revolutionized loss-of-function genetics by enabling sequence-specific suppression of virtually any gene. Furthermore, tetracycline response elements (TRE) can drive expression of short hairpin RNAs (shRNAs) for inducible and reversible target gene suppression. Here, we demonstrate the feasibility of transgenic inducible RNAi for suppression of essential genes. We set out to directly target cell proliferation by screening an RNAi library against DNA replication factors and identified multiple shRNAs against Replication Protein A, subunit 3 (RPA3). We generated transgenic mice with TRE-driven Rpa3 shRNAs whose expression enforced a reversible cell cycle arrest. In adult mice, the block in cell proliferation caused rapid atrophy of the intestinal epithelium which led to weight loss and lethality within 8–11 d of shRNA induction. Upon shRNA withdrawal, villus atrophy and weight loss were fully reversible. Thus, shRpa3 transgenic mice provide an interesting tool to study tissue maintenance and regeneration. Overall, we have established a robust system that serves the purpose of temperature-sensitive alleles in other model organisms, enabling inducible and reversible suppression of essential genes in a mammalian system.

McJunkin, Katherine; Mazurek, Anthony; Premsrirut, Prem K.; Zuber, Johannes; Dow, Lukas E.; Simon, Janelle; Stillman, Bruce; Lowe, Scott W.

2011-01-01

109

Comparative Genomics Analysis of Mycobacterium ulcerans for the Identification of Putative Essential Genes and Therapeutic Candidates  

PubMed Central

Mycobacterium ulcerans, the causative agent of Buruli ulcer, is the third most common mycobacterial disease after tuberculosis and leprosy. The present treatment options are limited and emergence of treatment resistant isolates represents a serious concern and a need for better therapeutics. Conventional drug discovery methods are time consuming and labor-intensive. Unfortunately, the slow growing nature of M. ulcerans in experimental conditions is also a barrier for drug discovery and development. In contrast, recent advancements in complete genome sequencing, in combination with cheminformatics and computational biology, represent an attractive alternative approach for the identification of therapeutic candidates worthy of experimental research. A computational, comparative genomics workflow was defined for the identification of novel therapeutic candidates against M. ulcerans, with the aim that a selected target should be essential to the pathogen, and have no homology in the human host. Initially, a total of 424 genes were predicted as essential from the M. ulcerans genome, via homology searching of essential genome content from 20 different bacteria. Metabolic pathway analysis showed that the most essential genes are associated with carbohydrate and amino acid metabolism. Among these, 236 proteins were identified as non-host and essential, and could serve as potential drug and vaccine candidates. Several drug target prioritization parameters including druggability were also calculated. Enzymes from several pathways are discussed as potential drug targets, including those from cell wall synthesis, thiamine biosynthesis, protein biosynthesis, and histidine biosynthesis. It is expected that our data will facilitate selection of M. ulcerans proteins for successful entry into drug design pipelines.

Tahir, Shifa; Tong, Yigang

2012-01-01

110

Comparative genomics analysis of Mycobacterium ulcerans for the identification of putative essential genes and therapeutic candidates.  

PubMed

Mycobacterium ulcerans, the causative agent of Buruli ulcer, is the third most common mycobacterial disease after tuberculosis and leprosy. The present treatment options are limited and emergence of treatment resistant isolates represents a serious concern and a need for better therapeutics. Conventional drug discovery methods are time consuming and labor-intensive. Unfortunately, the slow growing nature of M. ulcerans in experimental conditions is also a barrier for drug discovery and development. In contrast, recent advancements in complete genome sequencing, in combination with cheminformatics and computational biology, represent an attractive alternative approach for the identification of therapeutic candidates worthy of experimental research. A computational, comparative genomics workflow was defined for the identification of novel therapeutic candidates against M. ulcerans, with the aim that a selected target should be essential to the pathogen, and have no homology in the human host. Initially, a total of 424 genes were predicted as essential from the M. ulcerans genome, via homology searching of essential genome content from 20 different bacteria. Metabolic pathway analysis showed that the most essential genes are associated with carbohydrate and amino acid metabolism. Among these, 236 proteins were identified as non-host and essential, and could serve as potential drug and vaccine candidates. Several drug target prioritization parameters including druggability were also calculated. Enzymes from several pathways are discussed as potential drug targets, including those from cell wall synthesis, thiamine biosynthesis, protein biosynthesis, and histidine biosynthesis. It is expected that our data will facilitate selection of M. ulcerans proteins for successful entry into drug design pipelines. PMID:22912793

Butt, Azeem Mehmood; Nasrullah, Izza; Tahir, Shifa; Tong, Yigang

2012-01-01

111

A variant in the HS1-BP3 gene is associated with familial essential tremor  

PubMed Central

Background Genetic linkage studies have identified two susceptibility loci for essential tremor (ET) on chromosomes 3q13 (ETM1) and 2p24.1 (ETM2). Linkage disequilibrium studies in separate population samples from the United States and Singapore suggest an association between ET and loci at ETM2. Methods Fine mapping studies were conducted on multiplex and singleton US families linked to ETM2 using newly detected loci within the candidate interval to establish the minimal critical region (MCR) harboring an ET gene. The genes and transcripts within this interval were systematically analyzed by single-strand conformational polymorphism analysis and DNA sequencing. Results A 464-kb region between loci D2S2150 and etm1231 was defined as the MCR. The coding regions and flanking intronic splice sites of two genes and seven transcripts in this interval were evaluated for mutations. A missense mutation (828C?G) in the transcript FLJ14249 (HS1-BP3) was identified in one US family. This mutation was found in another apparently unrelated US family with ET and was absent in 150 control samples (300 chromosomes). The 828C?G mutation causes a substitution of a glycine for an alanine residue in the HS1-BP3 protein. The HS1-BP3 protein binds to proteins that are highly expressed in motor neurons and Purkinje cells and regulate the Ca2+/calmodulin-dependent protein kinase activation of tyrosine and tryptophan hydroxylase. Conclusions A rare variant in the HS1-BP3 gene that is associated with essential tremor (ET) in two families is reported. This finding will facilitate research on the functional role of this gene and related genes in the pathogenesis of ET.

Higgins, J.J.; Lombardi, R.Q.; Pucilowska, J.; Jankovic, J.; Tan, E.K.; Rooney, J.P.

2005-01-01

112

A study of the production of essential oils in chamomile hairy root cultures  

Microsoft Academic Search

Summary  The active substances in chamomile (Matricaria recutita L.) belong to chemically different structural types. The largest group of medically important compounds forming the essential\\u000a oils are primarily chamazulene, (?)-?-bisabolol, bisabololoxides, bisabolonoxide A,trans-?-farnesene, ?-farnesene, spathulenol and thecis\\/trans-en-in-dicycloethers. Flavonoids, coumarins, mucilages, mono- and oligosaccharides also have pharmacological effects. We studied\\u000a the production of essential oils in genetically transformed cultures. Sterile juvenile chamomile

E. Máday; É. Szöke; Zs. Muskáth; É. Lemberkovics

1999-01-01

113

Commercial opportunities for pesticides based on plant essential oils in agriculture, industry and consumer products  

Microsoft Academic Search

In spite of intensive research on plant natural products and insect-plant chemical interactions over the past three decades,\\u000a only two new types of botanical insecticides have been commercialized with any success in the past 15 years, those based on\\u000a neem seed extracts (azadirachtin), and those based on plant essential oils. Certain plant essential oils, obtained through\\u000a steam distillation and rich in

Murray B. Isman; Saber Miresmailli; Cristina Machial

2011-01-01

114

The Product of glnL Is Not Essential for Regulation of Bacterial Nitrogen Assimilation  

PubMed Central

The glnL product is not necessary for the control of expression of glnA and other nitrogen-regulated genes, but it presumably communicates reduntant information on the availability of ammonia from an ammonia-sensitive system consisting of the products of glnB and glnD to the regulatory products of glnF and glnG.

Backman, Keith C.; Chen, Yu-Mei; Ueno-Nishio, Shizue; Magasanik, Boris

1983-01-01

115

Current topics in the biotechnological production of essential amino acids, functional amino acids, and dipeptides.  

PubMed

Amino acids play important roles in both human and animal nutrition and in the maintenance of health. Here, amino acids are classified into three groups: first, essential amino acids, which are essential to nutrition; second, functional amino acids, recently found to be important in the promotion of physiological functions; and third, dipeptides, which are used to resolve problematic features of specific free amino acids, such as their instability or insolubility. This review focusses on recent researches concerning the microbial production of essential amino acids (lysine and methionine), functional amino acids (histidine and ornithine), and a dipeptide (L-alanyl-L-glutamine). PMID:24679256

Mitsuhashi, Satoshi

2014-04-01

116

Gene polymorphisms of the renin-angiotensin-aldosterone system and essential arterial hypertension in childhood.  

PubMed

In order to investigate the contribution of candidate genes in the renin-angiotensin-aldosterone system (RAAS) in pathogenesis of essential arterial hypertension (EAH), the I/D polymorphism of ACE gene, the M235T polymorphism of the angiotensinogen gene, and the angiotensin II type 1 receptor (AGT,R) A1166C gene polymorphism in a group of children with EAH were analyzed. Fifty-scven children, aged 8-19 years. with the diagnosis of EAH were included in the association study and were compared with 57 subjects with normal blood pressure (the control group). Arterial hypertension was defined as systolic/diastolic blood pressure measurements higher than 95 age-gender-height percentile of the adopted reference values. A trend was found towards an association between the M235T angiotensinogen gene polymorphism and EAH in childhood in a dominant model (odds ratio (OR) 2.1; 95% confidence interval (CI) 0.9-5.1; P = 0.077), whereas the authors failed to demonstrate an association between the ACE I/D gene polymorphism, or the A1166C AGT1R gene polymorphism and EAH in childhood. Additionally, evidence was found of interaction between the angiotensinogen-TT genotype and obesity on the risk of EAH in childhood (OR 19.3; 95% CI 1.1-77.3; P = 0.014). In conclusion, the M235T angiotensinogen gene polymorphism is considered alone as well as in interaction with obesity to be risk factors for EAH in childhood. PMID:12597535

Petrovic, Danijel; Bidovec, Matja; Peterlin, Borut

2002-01-01

117

An Arabidopsis tissue-specific RNAi method for studying genes essential to mitosis.  

PubMed

A large fraction of the genes in plants can be considered essential in the sense that when absent the plant fails to develop past the first few cell divisions. The fact that angiosperms pass through a haploid gametophyte stage can make it challenging to propagate such mutants even in the heterozygous condition. Here we describe a tissue-specific RNAi method that allows us to visualize cell division phenotypes in petals, which are large dispensable organs. Portions of the APETALA (AP3) and PISTILLATA (PI) promoters confer early petal-specific expression. We show that when either promoter is used to drive the expression of a beta-glucuronidase (GUS) RNAi transgene in plants uniformly expressing GUS, GUS expression is knocked down specifically in petals. We further tested the system by targeting the essential kinetochore protein CENPC and two different components of the Spindle Assembly Checkpoint (MAD2 and BUBR1). Plant lines expressing petal-specific RNAi hairpins targeting these genes exhibited an array of petal phenotypes. Cytological analyses of the affected flower buds confirmed that CENPC knockdown causes cell cycle arrest but provided no evidence that either MAD2 or BUBR1 are required for mitosis (although both genes are required for petal growth by this assay). A key benefit of the petal-specific RNAi method is that the phenotypes are not expressed in the lineages leading to germ cells, and the phenotypes are faithfully transmitted for at least four generations despite their pronounced effects on growth. PMID:23236491

Burgos-Rivera, Brunilís; Dawe, R Kelly

2012-01-01

118

Bcl10 is an essential regulator for A20 gene expression.  

PubMed

A20, a tumor suppressor in several types of lymphomas, has been suggested to be an nuclear factor kappa B (NF-?B) target gene; conversely, the deubiquitylation activity of A20 is required for inhibition of Bcl10-mediated activation of NF-?B. BCL10, which is activated in a recurrent chromosomal translocation that causes human mucosa-associated lymphoid tissue lymphomas, is known to be essential for NF-?B activation in B cells. We report here that Bcl10 upregulates endogenous A20 gene expression in B lymphocytes upon B-cell receptor engagement of anti-IgM. Transient transfection assays in HEK 293 cells indicate that Bcl10 can activate the A20 promoter, which contains NF-?B-binding sites. We also construct a theoretical structure of mouse Bcl10 and analyze the structure by molecular modeling and molecular dynamics simulation. Lastly, we found that marginal zone B cells from BCL10-transgenic mice proliferate more readily than wild-type B cells, whereas, surprisingly, the transgenic follicular B cells from these mice proliferate comparably to wild-type cells. Collectively, our results indicate that Bcl10 is an essential regulator of A20 gene expression and B-cell proliferation mediated by B-cell receptor signaling. PMID:23677497

Xu, Wu; Xue, Liquan; Sun, Yi; Henry, Aline; Battle, Jennifer M; Micault, Mathieu; Morris, Stephan W

2013-12-01

119

Coupling mutagenesis and parallel deep sequencing to probe essential residues in a genome or gene.  

PubMed

The sequence of a protein determines its function by influencing its folding, structure, and activity. Similarly, the most conserved residues of orthologous and paralogous proteins likely define those most important. The detection of important or essential residues is not always apparent via sequence alignments because these are limited by the depth of any given gene's phylogeny, as well as specificities that relate to each protein's unique biological origin. Thus, there is a need for robust and comprehensive ways of evaluating the importance of specific amino acid residues of proteins of known or unknown function. Here we describe an approach called Mut-seq, which allows the identification of virtually all of the essential residues present in a whole genome through the application of limited chemical mutagenesis, selection for function, and deep parallel genomic sequencing. Here we have applied this method to T7 bacteriophage and T7-like virus JSF7 of Vibrio cholerae. PMID:23401533

Robins, William P; Faruque, Shah M; Mekalanos, John J

2013-02-26

120

Bradykinin ?2 Receptor -58T/C Gene Polymorphism and Essential Hypertension: A Meta-Analysis  

PubMed Central

Background Research has shown that bradykinin ?2 receptor (BDKRB2) ?58T/C gene polymorphism is correlated with the risk of essential hypertension (EH), but the results remain inconclusive. Objective and Methods The objective of this study was to explore the association between BDKRB2?58T/C gene polymorphism and EH. A meta-analysis of 11 studies with 3882 subjects was conducted. Pooled odds ratios (ORs) for the association between BDKRB2?58T/C gene polymorphism and EH and their corresponding 95% confidence intervals (CIs) were estimated using the random effects model. Results The BDKRB2?58T/C gene polymorphism was significantly correlated with EH under an allelic genetic model (OR?=?1.24, 95% CI?=?1.05–1.46; P?=?0.01), a dominant genetic model (OR?=?0.65, 95% CI?=?0.47–0.90; P?=?0.01), a recessive genetic model (OR?=?1.146, 95% CI?=?1.035–1.269; P?=?0.009), a homozygote genetic model (OR?=?1.134, 95% CI?=?1.048–1.228; P?=?0.002), and a heterozygote genetic model (OR?=?1.060, 95% CI?=?1.009–1.112; P?=?0.019). Conclusions The BDKRB2?58T/C gene polymorphism is associated with increased EH risk. The results of this study suggest that carriers of the ?58C allele are susceptible to EH.

Li, Yan-yan; Zhang, Hui; Xu, Jian; Qian, Yun; Lu, Xin-zheng; Yang, Bing; Chen, Minglong; Yang, Zhi-jian; Cao, Ke-jiang

2012-01-01

121

Neural stem cell transcriptional networks highlight genes essential for nervous system development  

PubMed Central

Neural stem cells must strike a balance between self-renewal and multipotency, and differentiation. Identification of the transcriptional networks regulating stem cell division is an essential step in understanding how this balance is achieved. We have shown that the homeodomain transcription factor, Prospero, acts to repress self-renewal and promote differentiation. Among its targets are three neural stem cell transcription factors, Asense, Deadpan and Snail, of which Asense and Deadpan are repressed by Prospero. Here, we identify the targets of these three factors throughout the genome. We find a large overlap in their target genes, and indeed with the targets of Prospero, with 245 genomic loci bound by all factors. Many of the genes have been implicated in vertebrate stem cell self-renewal, suggesting that this core set of genes is crucial in the switch between self-renewal and differentiation. We also show that multiply bound loci are enriched for genes previously linked to nervous system phenotypes, thereby providing a shortcut to identifying genes important for nervous system development.

Southall, Tony D; Brand, Andrea H

2009-01-01

122

PhenoM: a database of morphological phenotypes caused by mutation of essential genes in Saccharomyces cerevisiae  

PubMed Central

About one-fifth of the genes in the budding yeast are essential for haploid viability and cannot be functionally assessed using standard genetic approaches such as gene deletion. To facilitate genetic analysis of essential genes, we and others have assembled collections of yeast strains expressing temperature-sensitive (ts) alleles of essential genes. To explore the phenotypes caused by essential gene mutation we used a panel of genetically engineered fluorescent markers to explore the morphology of cells in the ts strain collection using high-throughput microscopy. Here, we describe the design and implementation of an online database, PhenoM (Phenomics of yeast Mutants), for storing, retrieving, visualizing and data mining the quantitative single-cell measurements extracted from micrographs of the ts mutant cells. PhenoM allows users to rapidly search and retrieve raw images and their quantified morphological data for genes of interest. The database also provides several data-mining tools, including a PhenoBlast module for phenotypic comparison between mutant strains and a Gene Ontology module for functional enrichment analysis of gene sets showing similar morphological alterations. The current PhenoM version 1.0 contains 78?194 morphological images and 1?909?914 cells covering six subcellular compartments or structures for 775 ts alleles spanning 491 essential genes. PhenoM is freely available at http://phenom.ccbr.utoronto.ca/.

Jin, Ke; Li, Jingjing; Vizeacoumar, Frederick S.; Li, Zhijian; Min, Renqiang; Zamparo, Lee; Vizeacoumar, Franco J.; Datti, Alessandro; Andrews, Brenda; Boone, Charles; Zhang, Zhaolei

2012-01-01

123

Discovery of genes essential for heme biosynthesis through large-scale gene expression analysis  

PubMed Central

Summary Heme biosynthesis consists of a series of eight enzymatic reactions that originate in mitochondria and continue in the cytosol before returning to mitochondria. Although these core enzymes are well studied, additional mitochondrial transporters and regulatory factors are predicted to be required. To discover such unknown components, we utilized a large-scale computational screen to identify mitochondrial proteins whose transcripts consistently co-express with the core machinery of heme biosynthesis. We identified SLC25A39, SLC22A4 and TMEM14C, which are putative mitochondrial transporters, as well as C1orf69 and ISCA1, which are iron-sulfur cluster proteins. Targeted knockdowns of all five genes in zebrafish resulted in profound anemia without impacting erythroid lineage specification. Moreover, silencing of Slc25a39 in murine erythroleukemia cells impaired iron incorporation into protoporphyrin IX, and vertebrate Slc25a39 complemented an iron homeostasis defect in the orthologous yeast mtm1? deletion mutant. Our results advance the molecular understanding of heme biosynthesis and offer promising candidate genes for inherited anemias.

Nilsson, Roland; Schultz, Iman J.; Pierce, Eric L.; Soltis, Kathleen A.; Naranuntarat, Amornrat; Ward, Diane M.; Baughman, Joshua; Paradkar, Prasad N.; Kingsley, Paul D.; Culotta, Valeria C.; Kaplan, Jerry; Palis, James; Paw, Barry H.; Mootha, Vamsi K.

2009-01-01

124

Genome-Wide Analysis Reveals Novel Genes Essential for Heme Homeostasis in Caenorhabditis elegans  

PubMed Central

Heme is a cofactor in proteins that function in almost all sub-cellular compartments and in many diverse biological processes. Heme is produced by a conserved biosynthetic pathway that is highly regulated to prevent the accumulation of heme—a cytotoxic, hydrophobic tetrapyrrole. Caenorhabditis elegans and related parasitic nematodes do not synthesize heme, but instead require environmental heme to grow and develop. Heme homeostasis in these auxotrophs is, therefore, regulated in accordance with available dietary heme. We have capitalized on this auxotrophy in C. elegans to study gene expression changes associated with precisely controlled dietary heme concentrations. RNA was isolated from cultures containing 4, 20, or 500 µM heme; derived cDNA probes were hybridized to Affymetrix C. elegans expression arrays. We identified 288 heme-responsive genes (hrgs) that were differentially expressed under these conditions. Of these genes, 42% had putative homologs in humans, while genomes of medically relevant heme auxotrophs revealed homologs for 12% in both Trypanosoma and Leishmania and 24% in parasitic nematodes. Depletion of each of the 288 hrgs by RNA–mediated interference (RNAi) in a transgenic heme-sensor worm strain identified six genes that regulated heme homeostasis. In addition, seven membrane-spanning transporters involved in heme uptake were identified by RNAi knockdown studies using a toxic heme analog. Comparison of genes that were positive in both of the RNAi screens resulted in the identification of three genes in common that were vital for organismal heme homeostasis in C. elegans. Collectively, our results provide a catalog of genes that are essential for metazoan heme homeostasis and demonstrate the power of C. elegans as a genetic animal model to dissect the regulatory circuits which mediate heme trafficking in both vertebrate hosts and their parasites, which depend on environmental heme for survival.

Rao, Anita U.; Cerqueira, Gustavo C.; Mitreva, Makedonka; El-Sayed, Najib M.; Krause, Michael; Hamza, Iqbal

2010-01-01

125

The essential role of the Deinococcus radiodurans ssb gene in cell survival and radiation tolerance.  

PubMed

Recent evidence has implicated single-stranded DNA-binding protein (SSB) expression level as an important factor in microbial radiation resistance. The genome of the extremely radiation resistant bacterium Deinococcus radiodurans contains genes for two SSB homologs: the homodimeric, canonical Ssb, encoded by the gene ssb, and a novel pentameric protein encoded by the gene ddrB. ddrB is highly induced upon exposure to radiation, and deletions result in decreased radiation-resistance, suggesting an integral role of the protein in the extreme resistance exhibited by this organism. Although expression of ssb is also induced after irradiation, Ssb is thought to be involved primarily in replication. In this study, we demonstrate that Ssb in D. radiodurans is essential for cell survival. The lethality of an ssb deletion cannot be complemented by providing ddrB in trans. In addition, the radiation-sensitive phenotype conferred by a ddrB deletion is not alleviated by providing ssb in trans. By altering expression of the ssb gene, we also show that lower levels of transcription are required for optimal growth than are necessary for high radiation resistance. When expression is reduced to that of E. coli, ionizing radiation resistance is similarly reduced. UV resistance is also decreased under low ssb transcript levels where growth is unimpaired. These results indicate that the expression of ssb is a key component of both normal cellular metabolism as well as pathways responsible for the high radiation tolerance of D. radiodurans. PMID:23951213

Lockhart, J Scott; DeVeaux, Linda C

2013-01-01

126

The Essential Role of the Deinococcus radiodurans ssb Gene in Cell Survival and Radiation Tolerance  

PubMed Central

Recent evidence has implicated single-stranded DNA-binding protein (SSB) expression level as an important factor in microbial radiation resistance. The genome of the extremely radiation resistant bacterium Deinococcus radiodurans contains genes for two SSB homologs: the homodimeric, canonical Ssb, encoded by the gene ssb, and a novel pentameric protein encoded by the gene ddrB. ddrB is highly induced upon exposure to radiation, and deletions result in decreased radiation-resistance, suggesting an integral role of the protein in the extreme resistance exhibited by this organism. Although expression of ssb is also induced after irradiation, Ssb is thought to be involved primarily in replication. In this study, we demonstrate that Ssb in D. radiodurans is essential for cell survival. The lethality of an ssb deletion cannot be complemented by providing ddrB in trans. In addition, the radiation-sensitive phenotype conferred by a ddrB deletion is not alleviated by providing ssb in trans. By altering expression of the ssb gene, we also show that lower levels of transcription are required for optimal growth than are necessary for high radiation resistance. When expression is reduced to that of E. coli, ionizing radiation resistance is similarly reduced. UV resistance is also decreased under low ssb transcript levels where growth is unimpaired. These results indicate that the expression of ssb is a key component of both normal cellular metabolism as well as pathways responsible for the high radiation tolerance of D. radiodurans.

Lockhart, J. Scott; DeVeaux, Linda C.

2013-01-01

127

Solvent-Free Production of Bioflavors by Enzymatic Esterification of Citronella (Cymbopogon winterianus) Essential Oil.  

PubMed

Enzymatic esterification of citronella essential oil towards the production of geranyl and citronellyl esters may present great scientific and technological interest due to the well-known drawbacks of the chemical-catalyzed route. In this context, this work reports the maximization of geranyl and citronellyl esters production by esterification of oleic and propionic acids in a solvent-free system using a commercial immobilized lipase as catalyst. Results of the reactions showed that the strategy adopted for the experimental design proved to be useful in evaluating the effects of the studied variables on the reaction conversion using Novozym 435 as catalyst. The operating conditions that maximized the production of each ester were determined, leading, in a general way, to conversions of about 90% for all systems. New experimental data on enzymatic esterification of crude citronella essential oil for geranyl and citronellyl esters production in solvent-free system are reported in this work. PMID:21976151

Paroul, Natália; Grzegozeski, Luana Paula; Chiaradia, Viviane; Treichel, Helen; Cansian, Rogério L; Oliveira, J Vladimir; de Oliveira, Débora

2011-10-01

128

Introns are essential for growth-regulated expression of the mouse thymidylate synthase gene.  

PubMed Central

The thymidylate synthase (TS) gene is expressed at much higher levels in proliferating cells than in quiescent cells. We have been studying the sequences that are important for regulating the mouse TS gene. We previously showed that DNA sequences upstream of the essential promoter elements as well as downstream of the ATG codon are both necessary (but neither is sufficient) for normal regulation in growth-stimulated cells. In the present study, we examined the possible roles of the coding region, polyadenylation signal, and introns as downstream regulatory elements. Minigenes consisting of 1 kb of the TS 5'-flanking region, the coding region (with or without various introns at their normal locations), and polyadenylation signals from the TS gene, the human beta-globin gene, and the bovine growth hormone gene were stably transfected into wild-type mouse 3T6 cells. Minigenes that contained introns 5 and 6, 1 and 2, or 1 alone were regulated regardless of which polyadenylation signal was included. A minigene that contained an internally deleted version of intron 1 was also regulated in response to growth stimulation. However, when all introns were omitted, there was little if any change in the level of minigene expression as cells progressed from G1 through S phase. These observations indicate that TS introns contain sequences that are necessary for normal growth-regulated expression of the mouse TS gene. These sequences appear to be associated with sequences that are important for splicing and to function in cooperation with upstream regulatory elements to bring about normal S-phase-specific expression. Images

Ash, J; Ke, Y; Korb, M; Johnson, L F

1993-01-01

129

Effects of selected essential oils on the growth and production of ochratoxin A by Penicillium verrucosum.  

PubMed

Abstract Essential oils from oregano (Origanum vulgare L.), mint (Mentha piperita L.), fennel (Foeniculum vulgare Mill.), and pine (Abies alba Mill.) needles and cones, and their active substances thymol, carvacrol, menthol, and anisaldehyde were tested for antifungal activity against Penicillium verrucosum. The lowest minimal inhibitory concentrations (MICs) were achieved for essential oil of oregano, followed by carvacrol, thymol, and menthol. These antifungal components were further investigated, as the main aim of our study was to elucidate the effect of natural antifungals on ochratoxin A production. During 21 days of exposure, the growth of P. verrucosum, and subsequently the production of ochratoxin A, was fully inhibited by thymol at ½ MIC (0.0625 mg mL-1), but menthol at ¼ and ½ MIC (0.1875 and 3750 mg mL-1) showed no growth inhibition. After 21 days of incubation, the greatest inhibitory effect on ochratoxin production (inhibition was 96.9 %) was also achieved with thymol at ¼ MIC (0.0313 mg mL-1). Essential oil of oregano (¼ MIC, 0.2930 ?L mL-1) and carvacrol (½ MIC, 0.1953 ?L mL-1) stimulate production of ochratoxin A at 13.9 % to 28.8 %, respectively. The observed antifungal effects depended on the agent, the concentration used, and the time of interaction between the agent and P. verrucosum. Our results indicate the possibility of using oregano essential oil as a substitute for artificial preservatives in certain foods, but further research is needed. PMID:24945417

Jeršek, Barbara; Poklar Ulrih, Nataša; Skrt, Mihaela; Gavari?, Neda; Božin, Biljana; Smole Možina, Sonja

2014-06-01

130

Genetic and physical analyses of a cluster of genes essential for xanthan gum biosynthesis in Xanthomonas campestris.  

PubMed Central

Xanthomonas campestris produces copious amounts of a complex exopolysaccharide, xanthan gum. Nonmucoid mutants, defective in synthesis of xanthan polysaccharide, were isolated after nitrosoguanidine mutagenesis. To isolate genes essential for xanthan polysaccharide synthesis (xps), a genomic library of X. campestris DNA, partially digested with SalI and ligated into the broad-host-range cloning vector pRK293, was constructed in Escherichia coli. The pooled clone bank was conjugated en masse from E. coli into three nonmucoid mutants by using pRK2013, which provides plasmid transfer functions. Kanamycin-resistant exconjugants were then screened for the ability to form mucoid colonies. Analysis of plasmids from several mucoid exconjugants indicated that overlapping segments of DNA had been cloned. These plasmids were tested for complementation of eight additional nonmucoid mutants. A 22-kilobase (kb) region of DNA was defined physically by restriction enzyme analysis and genetically by ability to restore mucoid phenotype to 10 of the 11 nonmucoid mutants tested. This region was further defined by subcloning and by transposon mutagenesis with mini-Mu(Tetr), with subsequent analysis of genetic complementation of nonmucoid mutants. A region of 13.5 kb of DNA was determined to contain at least five complementation groups. The effect of plasmids containing cloned xps genes on xanthan gum synthesis was evaluated. One plasmid, pCHC3, containing a 12.4-kb insert and at least four linked xanthan biosynthetic genes, increased the production of xanthan gum by 10% and increased the extent of pyruvylation of the xanthan side chains by about 45%. This indicates that a gene affecting pyruvylation of xanthan gum is linked to this cluster of xps genes.

Harding, N E; Cleary, J M; Cabanas, D K; Rosen, I G; Kang, K S

1987-01-01

131

A study of the production of essential oils in chamomile hairy root cultures.  

PubMed

The active substances in chamomile (Matricaria recutita L.) belong to chemically different structural types. The largest group of medically important compounds forming the essential oils are primarily chamazulene, (-)-alpha-bisabolol, bisabololoxides, bisabolonoxide A, trans-beta-farnesene, alpha-farnesene, spathulenol and the cis/trans-en-in-dicycloethers. Flavonoids, coumarins, mucilages, mono- and oligosaccharides also have pharmacological effects. We studied the production of essential oils in genetically transformed cultures. Sterile juvenile chamomile plants were infected with A4-Y strains of Agrobacterium rhizogenes. They are known plant pathogens and are capable of inducing so-called hairy roots. The transfer DNA segment of the Ri-virulence plasmid of A. rhizogenes becomes integrated in the genome of the plant cells. The isolated hairy roots grow rapidly on hormone-free media. In order to obtain bacteria-free media, we cultured the transformed roots on Murashige-Skoog (MS) medium supplemented with carbenicillin (800 mg/l). To study the production of essential oils, the clones were propagated on liquid and solid MS and Gamborg (B5) media, respectively. According to gas chromatography, the composition of the essential oil of hairy root cultures on different media was found to be similar, but differing in proportion. The main component of the essential oil which was identified by gas chromatography and mass spectrometry was trans-beta-farnesene, as in the intact roots. PMID:10892892

Máday, E; Szöke, E; Muskáth, Z; Lemberkovics, E

1999-01-01

132

Insecticidal Activity of the Essential Oils from Different Plants Against Three Stored-Product Insects  

PubMed Central

This study was conducted to determine the insecticidal activity of essential oils from oregano, Origanum onites L. (Lamiales: Lamiaceae), savory, Satureja thymbra L. (Lamiales: Lamiaceae), and myrtle, Myrtus communis L. (Rosales: Myrtaceae) against three stored-product insects. Essential oils from three species of plants were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified using gas chromatography-mass spectrometry and their insecticidal activity was tested against adults of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), the Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae) and the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae). While the major compound found in oregano and savory was carvacrol, the main constituent of the myrtle was linalool. Among the tested insects, A. obtectus was the most tolerant species against the essential oils. However, the insecticidal activity of the myrtle oil was more pronounced than other oils tested against A. obtectus adults. The essential oils of oregano and savory were highly effective against P. interpunctella and E. kuehniella, with 100% mortality obtained after 24 h at 9 and 25 µl/l air for P. interpunctella and E. kuehniella, respectively. LC50 and LC99 values of each essential oil were estimated for each insect species.

Ayvaz, Abdurrahman; Sagdic, Osman; Karaborklu, Salih; Ozturk, Ismet

2010-01-01

133

Assessment of inhibitory potential of essential oils on natural mycoflora and Fusarium mycotoxins production in wheat  

PubMed Central

Background In the last years essential oils from different plants were used in the prevention of fungi and mycotoxins accumulation in cereals. The most attractive aspect derived from using of essential oils as seed grains protectants is due to their non-toxicity. This study was focused on assessment the inhibitory effect of some essential oils: Melissa officinalis (O1), Salvia officinalis (O2), Coriandrum sativum (O3), Thymus vulgaris (O4) Mentha piperita (O5) and Cinnamomum zeylanicum (O6) against natural mycoflora and Fusarium mycotoxins production correlated with their antioxidants properties. Results All essential oils showed inhibitory effect on fungal contamination of wheat seeds. This ability was dose-dependent. The highest inhibitory effect on Fusarium and Aspergillus fungi was recorded after 5?days of treatment. Fungi such as yeast (Pichia, Saccharomyces and Hyphopichia) were predominantly on seeds mycoflora after 22?days. Each treatment had a selective inhibitory effect on frequency of fungus genera. After 5?days of treatment the most fungicidal effect was recorder for O4, followed by O1. In terms of essential oils effect on mycotoxins development, the best control on fumonisins (FUMO) production was recorded for O6. The antioxidant properties of essential oils decreased in order: O4?>?O1?>?O6?>?O5?>?O2?>?O3. Also, our data suggested that there is a significant negative correlation between antioxidant properties and seed contamination index (SCI), but there was not recorded a good correlation between antioxidant properties and FUMO content. Conclusions Based on proven antifungal and antimycotoxin effects as well as their antioxidant properties, the essential oils could be recommended as natural preservatives for stored cereals. The highest inhibition of fungal growth was noted after 5?days of treatment and decreased after 22?days.

2013-01-01

134

Essential and non-essential DNA replication genes in the model halophilic Archaeon, Halobacterium sp. NRC1  

Microsoft Academic Search

BACKGROUND: Information transfer systems in Archaea, including many components of the DNA replication machinery, are similar to those found in eukaryotes. Functional assignments of archaeal DNA replication genes have been primarily based upon sequence homology and biochemical studies of replisome components, but few genetic studies have been conducted thus far. We have developed a tractable genetic system for knockout analysis

Brian R Berquist; Priya DasSarma; Shiladitya DasSarma

2007-01-01

135

Complex formation and interactions between transcription factors essential for human prolactin receptor gene transcription.  

PubMed

The protein association of estrogen receptor ? ER? with DNA-bound SP1 and C/EBP? is essential for the 17?-estradiol (E2)-induced activation of human prolactin receptor (hPRLR) gene transcription. Protein-protein interaction and complex formation at the hPIII promoter of hPRLR was investigated. The basic region and leucine zipper (bZIP) of C/EBP?, zinc finger (ZF) motifs of SP1, and the DNA binding domain of ER? were identified as regions responsible for the interactions between transfactors. The E2-induced interaction was confirmed by bioluminescence resonance energy transfer (BRET) assays of live cells. The combination of BRET/bimolecular luminescence complementation assay revealed that ER? exists as a constitutive homodimer, and E2 induced a change(s) in ER? homodimer conformation favorable for its association with C/EBP? and SP1. Chromatin immunoprecipitation and small interfering RNA knockdown of members of the complex in breast cancer cells demonstrated the endogenous recruitment of components of the complex onto the hPIII promoter of the hPRLR gene. SP1 is the preferred transfactor for the recruitment of ER? to the complex that facilitates the C/EBP? association. The E2/ER?-induced hPRLR transcription was demonstrated in ER?-negative breast cancer cells. This study indicates that the enhanced complex formation of ER? dimer with SP1 and C/EBP? by E2 has an essential role in the transcriptional activation of the hPRLR gene. PMID:21670145

Kang, Jung-Hoon; Tsai-Morris, Chon-Hwa; Dufau, Maria L

2011-08-01

136

Small genes\\/gene-products in Escherichia coli K-12  

Microsoft Academic Search

Forty-two protein spots of observed Mr 6–15 kDa were resolved by two-dimensional gel electrophoresis, stained by Coomassie blue and subjected to Edman microsequencing. All of the proteins could be related back to their encoding open reading frames, thereby vindicating the bioinformatic tools currently utilised in their identification. However, only 14\\/42 gene-products were expressed as annotated. Translation was confirmed for 14

Valerie C Wasinger; Ian Humphery-Smith

1998-01-01

137

Examination of the relationship between essential genes in PPI network and hub proteins in reverse nearest neighbor topology  

PubMed Central

Background In many protein-protein interaction (PPI) networks, densely connected hub proteins are more likely to be essential proteins. This is referred to as the "centrality-lethality rule", which indicates that the topological placement of a protein in PPI network is connected with its biological essentiality. Though such connections are observed in many PPI networks, the underlying topological properties for these connections are not yet clearly understood. Some suggested putative connections are the involvement of essential proteins in the maintenance of overall network connections, or that they play a role in essential protein clusters. In this work, we have attempted to examine the placement of essential proteins and the network topology from a different perspective by determining the correlation of protein essentiality and reverse nearest neighbor topology (RNN). Results The RNN topology is a weighted directed graph derived from PPI network, and it is a natural representation of the topological dependences between proteins within the PPI network. Similar to the original PPI network, we have observed that essential proteins tend to be hub proteins in RNN topology. Additionally, essential genes are enriched in clusters containing many hub proteins in RNN topology (RNN protein clusters). Based on these two properties of essential genes in RNN topology, we have proposed a new measure; the RNN cluster centrality. Results from a variety of PPI networks demonstrate that RNN cluster centrality outperforms other centrality measures with regard to the proportion of selected proteins that are essential proteins. We also investigated the biological importance of RNN clusters. Conclusions This study reveals that RNN cluster centrality provides the best correlation of protein essentiality and placement of proteins in PPI network. Additionally, merged RNN clusters were found to be topologically important in that essential proteins are significantly enriched in RNN clusters, and biologically important because they play an important role in many Gene Ontology (GO) processes.

2010-01-01

138

Acidic pH induced STM1485 gene is essential for intracellular replication of Salmonella  

PubMed Central

During the course of infection, Salmonella has to face several potentially lethal environmental conditions, one such being acidic pH. The ability to sense and respond to the acidic pH is crucial for the survival and replication of Salmonella. The physiological role of one gene (STM1485) involved in this response, which is upregulated inside the host cells (by 90- to 113-fold) is functionally characterized in Salmonella pathogenesis. In vitro, the ?STM1485 neither exhibited any growth defect at pH 4.5 nor any difference in the acid tolerance response. The ?STM1485 was compromised in its capacity to proliferate inside the host cells and complementation with STM1485 gene restored its virulence. We further demonstrate that the surface translocation of Salmonella pathogenicity island-2 (SPI-2) encoded translocon proteins, SseB and SseD were reduced in the ?STM1485. The increase in co-localization of this mutant with lysosomes was also observed. In addition, the ?STM1485 displayed significantly reduced competitive indices (CI) in spleen, liver and mesenteric lymph nodes in murine typhoid model when infected by intra-gastric route. Based on these results, we conclude that the acidic pH induced STM1485 gene is essential for intracellular replication of Salmonella.

Allam, Uday Sankar; Krishna, M. Gopala; Sen, Minakshi; Thomas, Rony; Lahiri, Amit; Gnanadhas, Divya Prakash; Chakravortty, Dipshikha

2012-01-01

139

Repression of Essential Chloroplast Genes Reveals New Signaling Pathways and Regulatory Feedback Loops in Chlamydomonas[W  

PubMed Central

Although reverse genetics has been used to elucidate the function of numerous chloroplast proteins, the characterization of essential plastid genes and their role in chloroplast biogenesis and cell survival has not yet been achieved. Therefore, we developed a robust repressible chloroplast gene expression system in the unicellular alga Chlamydomonas reinhardtii based mainly on a vitamin-repressible riboswitch, and we used this system to study the role of two essential chloroplast genes: ribosomal protein S12 (rps12), encoding a plastid ribosomal protein, and rpoA, encoding the ?-subunit of chloroplast bacterial-like RNA polymerase. Repression of either of these two genes leads to the arrest of cell growth, and it induces a response that involves changes in expression of nuclear genes implicated in chloroplast biogenesis, protein turnover, and stress. This response also leads to the overaccumulation of several plastid transcripts and reveals the existence of multiple negative regulatory feedback loops in the chloroplast gene circuitry.

Ramundo, Silvia; Rahire, Michele; Schaad, Olivier; Rochaix, Jean-David

2013-01-01

140

Endosymbiosis in trypanosomatids: the genomic cooperation between bacterium and host in the synthesis of essential amino acids is heavily influenced by multiple horizontal gene transfers  

PubMed Central

Background Trypanosomatids of the genera Angomonas and Strigomonas live in a mutualistic association characterized by extensive metabolic cooperation with obligate endosymbiotic Betaproteobacteria. However, the role played by the symbiont has been more guessed by indirect means than evidenced. Symbiont-harboring trypanosomatids, in contrast to their counterparts lacking symbionts, exhibit lower nutritional requirements and are autotrophic for essential amino acids. To evidence the symbiont’s contributions to this autotrophy, entire genomes of symbionts and trypanosomatids with and without symbionts were sequenced here. Results Analyses of the essential amino acid pathways revealed that most biosynthetic routes are in the symbiont genome. By contrast, the host trypanosomatid genome contains fewer genes, about half of which originated from different bacterial groups, perhaps only one of which (ornithine cyclodeaminase, EC:4.3.1.12) derived from the symbiont. Nutritional, enzymatic, and genomic data were jointly analyzed to construct an integrated view of essential amino acid metabolism in symbiont-harboring trypanosomatids. This comprehensive analysis showed perfect concordance among all these data, and revealed that the symbiont contains genes for enzymes that complete essential biosynthetic routes for the host amino acid production, thus explaining the low requirement for these elements in symbiont-harboring trypanosomatids. Phylogenetic analyses show that the cooperation between symbionts and their hosts is complemented by multiple horizontal gene transfers, from bacterial lineages to trypanosomatids, that occurred several times in the course of their evolution. Transfers occur preferentially in parts of the pathways that are missing from other eukaryotes. Conclusion We have herein uncovered the genetic and evolutionary bases of essential amino acid biosynthesis in several trypanosomatids with and without endosymbionts, explaining and complementing decades of experimental results. We uncovered the remarkable plasticity in essential amino acid biosynthesis pathway evolution in these protozoans, demonstrating heavy influence of horizontal gene transfer events, from Bacteria to trypanosomatid nuclei, in the evolution of these pathways.

2013-01-01

141

The BLADE-ON-PETIOLE genes are essential for abscission zone formation in Arabidopsis.  

PubMed

The Arabidopsis BLADE-ON-PETIOLE 1 (BOP1) and BOP2 genes encode redundant transcription factors that promote morphological asymmetry during leaf and floral development. Loss-of-function bop1 bop2 mutants display a range of developmental defects, including a loss of floral organ abscission. Abscission occurs along specialised cell files, called abscission zones (AZs) that develop at the junction between the leaving organ and main plant body. We have characterized the bop1 bop2 abscission phenotype to determine how BOP1 and BOP2 contribute to the known abscission developmental framework. Histological analysis and petal breakstrength measurements of bop1 bop2 flowers show no differentiation of floral AZs. Furthermore, vestigial cauline leaf AZs are also undifferentiated in bop1 bop2 mutants, suggesting that BOP proteins are essential to establish AZ cells in different tissues. In support of this hypothesis, BOP1/BOP2 activity is required for both premature floral organ abscission and the ectopic abscission of cauline leaves promoted by the INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) gene under the control of the constitutive CaMV 35S promoter. Expression of several abscission-related marker genes, including IDA, is relatively unperturbed in bop1 bop2 mutants, indicating that these AZ genes respond to positional cues that are independent of BOP1/BOP2 activity. We also show that BOP1 and BOP2 promote growth of nectary glands, which normally develop at the receptacle adjacent to developing AZs. Taken together, these data suggest that BOP1/BOP2 activity is required for multiple cell differentiation events in the proximal regions of inflorescence lateral organs. PMID:18339677

McKim, Sarah M; Stenvik, Grethe-Elisabeth; Butenko, Melinka A; Kristiansen, Wenche; Cho, Sung Ki; Hepworth, Shelley R; Aalen, Reidunn B; Haughn, George W

2008-04-01

142

Tescalcin is an essential factor in megakaryocytic differentiation associated with Ets family gene expression  

PubMed Central

We show here that the process of megakaryocytic differentiation requires the presence of the recently discovered protein tescalcin. Tescalcin is dramatically upregulated during the differentiation and maturation of primary megakaryocytes or upon PMA-induced differentiation of K562 cells. This upregulation requires sustained signaling through the ERK pathway. Overexpression of tescalcin in K562 cells initiates events of spontaneous megakaryocytic differentiation, such as expression of specific cell surface antigens, inhibition of cell proliferation, and polyploidization. Conversely, knockdown of this protein in primary CD34+ hematopoietic progenitors and cell lines by RNA interference suppresses megakaryocytic differentiation. In cells lacking tescalcin, the expression of Fli-1, Ets-1, and Ets-2 transcription factors, but not GATA-1 or MafB, is blocked. Thus, tescalcin is essential for the coupling of ERK cascade activation with the expression of Ets family genes in megakaryocytic differentiation.

Levay, Konstantin; Slepak, Vladlen Z.

2007-01-01

143

FGF-regulated Etv genes are essential for repressing Shh expression in mouse limb buds.  

PubMed

Anterior-posterior (A-P) patterning of the vertebrate limb is controlled by sonic hedgehog (SHH) signaling, and the precise restriction of Shh expression to the posterior limb bud is essential for its polarizing effect. Fibroblast growth factor (FGF) signaling, a key control of proximal-distal (P-D) limb outgrowth, is known to promote Shh expression in the posterior limb bud. Here, we show that conditional knockout of the FGF-activated transcription factor genes Etv4 and Etv5 in mouse led to ectopic Shh expression in the anterior limb bud and a preaxial polydactyly (PPD) skeletal phenotype. These unexpected results suggest that ETV4 and ETV5 act downstream of FGF signaling to inhibit Shh expression in the anterior limb bud. This finding elucidates a novel aspect of the mechanism coordinating limb development along the A-P and P-D axes. PMID:19386269

Zhang, Zhen; Verheyden, Jamie M; Hassell, John A; Sun, Xin

2009-04-01

144

FGF-regulated Etv genes are essential for repressing Shh expression in mouse limb buds  

PubMed Central

SUMMARY Anterior-posterior (A-P) patterning of the vertebrate limb is controlled by sonic hedgehog (SHH) signaling, and the precise restriction of Shh expression to the posterior limb bud is essential for its polarizing effect. Fibroblast growth factor (FGF) signaling, a key control of proximal-distal (P-D) limb outgrowth, is known to promote Shh expression in the posterior limb bud. Here we show that conditional knockout of FGF-activated transcription factor genes Etv4 and Etv5 in mouse led to ectopic Shh expression in the anterior limb bud, and a preaxial polydactyly (PPD) skeletal phenotype. These unexpected results suggest that ETV4 and ETV5 act downstream of FGF signaling to inhibit Shh expression in the anterior limb bud. This finding elucidates a novel aspect of the mechanism coordinating limb development along the A-P and P-D axes.

Zhang, Zhen; Verheyden, Jamie M; Hassell, John A.; Sun, Xin

2012-01-01

145

Early estrogen-induced gene 1, a novel RANK signaling component, is essential for osteoclastogenesis  

PubMed Central

The receptor activator of NF-?B (RANK) and immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptors are essential factors involved in regulating osteoclast formation and bone remodeling. Here, we identify early estrogen-induced gene 1 (EEIG1) as a novel RANK ligand (RANKL)-inducible protein that physically interacts with RANK and further associates with Gab2, PLC?2 and Tec/Btk kinases upon RANKL stimulation. EEIG1 positively regulates RANKL-induced osteoclast formation, likely due to its ability to facilitate RANKL-stimulated PLC?2 phosphorylation and NFATc1 induction. In addition, an inhibitory peptide designed to block RANK-EEIG1 interaction inhibited RANKL-induced bone destruction by reducing osteoclast formation. Together, our results identify EEIG1 as a novel RANK signaling component controlling RANK-mediated osteoclast formation, and suggest that targeting EEIG1 might represent a new therapeutic strategy for the treatment of pathological bone resorption.

Choi, Han Kyoung; Kang, Hye Ri; Jung, Eutteum; Kim, Tae Eon; Lin, Jing Jing; Lee, Soo Young

2013-01-01

146

Conditional essentiality of the csrA gene in Escherichia coli.  

PubMed

CsrA is a global posttranscriptional regulator of numerous physiological processes, such as glycogenesis and glycolysis. Here, we show that the csrA gene of Escherichia coli is essential for growth on LB and on synthetic medium containing glycolytic carbon sources. However, csrA is not necessary for growth on synthetic medium containing pyruvate, showing that the Krebs cycle is functional in the csrA::cat deletion mutant. Deletion of the glgCAP operon in the csrA::cat mutant restored the ability to grow on LB and on synthetic medium containing glycolytic carbon sources, showing that growth inhibition is due to an excess of glycogen synthesis. PMID:19103924

Timmermans, Johan; Van Melderen, Laurence

2009-03-01

147

Early estrogen-induced gene 1, a novel RANK signaling component, is essential for osteoclastogenesis.  

PubMed

The receptor activator of NF-?B (RANK) and immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptors are essential factors involved in regulating osteoclast formation and bone remodeling. Here, we identify early estrogen-induced gene 1 (EEIG1) as a novel RANK ligand (RANKL)-inducible protein that physically interacts with RANK and further associates with Gab2, PLC?2 and Tec/Btk kinases upon RANKL stimulation. EEIG1 positively regulates RANKL-induced osteoclast formation, likely due to its ability to facilitate RANKL-stimulated PLC?2 phosphorylation and NFATc1 induction. In addition, an inhibitory peptide designed to block RANK-EEIG1 interaction inhibited RANKL-induced bone destruction by reducing osteoclast formation. Together, our results identify EEIG1 as a novel RANK signaling component controlling RANK-mediated osteoclast formation, and suggest that targeting EEIG1 might represent a new therapeutic strategy for the treatment of pathological bone resorption. PMID:23478294

Choi, Han Kyoung; Kang, Hye Ri; Jung, Eutteum; Kim, Tae Eon; Lin, Jing Jing; Lee, Soo Young

2013-04-01

148

Cloning of hydrogenase genes and fine structure analysis of an operon essential for H/sub 2/ metabolism in Escherichia coli  

SciTech Connect

Escherichia coli has two unlinked genes that code for hydrogenase synthesis and activity. The DNA fragments containing the two genes (hydA and hydB) were cloned into a plasmid vector, pBR322. The plasmids containing the hyd genes (pSE-290 and pSE-111 carrying the hydA and hydB genes, respectively) were used to genetically map a total of 51 mutant strains with defects in hydrogenase activity. A total of 37 mutants carried a mutation in the hydB gene, whereas the remaining 14 hyd were hydA. This complementation analysis also established the presence of two new genes, so far unidentified, one coding for formate dehydrogenase-2 (fdv) and another producing an electron transport protein (fhl) coupling formate dehydrogenase-2 to hydrogenase. Three of the four genes, hydB, fhl, and fdv, may constitute a single operon, and all three genes are carried by a 5.6-kilobase-pair chromosomal DNA insert in plasmid pSE-128. Plasmids carrying a part of this 5.6-kilobase-pair DNA (pSE-130) or fragments derived from this DNA in different orientations (pSE-126 and pSE-129) inhibited the production of active formate hydrogenlyase. This inhibition occurred even in a prototrophic E. coli, strain K-10, but only during an early induction period. These results, based on complementation analysis with cloned DNA fragments, show that both hydA and hydB genes are essential for the production of active hydrogenase. For the expression of active formate hydrogenlyase, two other gene products, fhl and fdv are also needed. All four genes map between 58 and 59 min in the E. coli chromosome.

Sankar, P.; Lee, J.H.; Shanmugam, K.T.

1985-04-01

149

Genome-wide identification of Streptococcus pneumoniae genes essential for bacterial replication during experimental meningitis.  

PubMed

Meningitis is the most serious of invasive infections caused by the Gram-positive bacterium Streptococcus pneumoniae. Vaccines protect only against a limited number of serotypes, and evolving bacterial resistance to antimicrobials impedes treatment. Further insight into the molecular pathogenesis of invasive pneumococcal disease is required in order to enable the development of new or adjunctive treatments and/or pneumococcal vaccines that are efficient across serotypes. We applied genomic array footprinting (GAF) in the search for S. pneumoniae genes that are essential during experimental meningitis. A total of 6,000 independent TIGR4 marinerT7 transposon mutants distributed over four libraries were injected intracisternally into rabbits, and cerebrospinal fluid (CSF) was collected after 3, 9, and 15 h. Microarray analysis of mutant-specific probes from CSF samples and inocula identified 82 and 11 genes mutants of which had become attenuated or enriched, respectively, during infection. The results point to essential roles for capsular polysaccharides, nutrient uptake, and amino acid biosynthesis in bacterial replication during experimental meningitis. The GAF phenotype of a subset of identified targets was followed up by detailed studies of directed mutants in competitive and noncompetitive infection models of experimental rat meningitis. It appeared that adenylosuccinate synthetase, flavodoxin, and LivJ, the substrate binding protein of a branched-chain amino acid ABC transporter, are relevant as targets for future therapy and prevention of pneumococcal meningitis, since their mutants were attenuated in both models of infection as well as in competitive growth in human cerebrospinal fluid in vitro. PMID:21041497

Molzen, T E; Burghout, P; Bootsma, H J; Brandt, C T; van der Gaast-de Jongh, Christa E; Eleveld, M J; Verbeek, M M; Frimodt-Møller, N; Østergaard, C; Hermans, P W M

2011-01-01

150

Development of shuttle vectors for evaluation of essential regulator regulated gene expression in Staphylococcus aureus  

PubMed Central

We describe the construction of a series of shuttle vectors for Staphylococcus aureus. In order to determine transcriptional regulation by essential regulators, we constructed promoterless luxABCDE reporter system using a TetR-regulated antisense RNA expression vector, pJYJ909, which is composed of S. aureus plasmid pE194, the Gram? plasmid pUC18, a TetR regulatory cassette, and Pxyl/teto-driven yhcS antisense expression construct. The reformed shuttle vector was utilized to construct an opuCA promoter-luxABCDE fusion and simultaneously examine transcriptional regulation by measuring bioluminescence intensity during down-regulating yhcSR. In addition, we utilized the same plasmid, pJYJ909, and constructed a Pspac-driven constant expression system, which allows us to determine the complementary effect of overexpression of opuCA operon modulated by yhcSR. These plasmids provide important tools for elucidating regulatory mechanisms for genes that are essential for bacterial growth in S. aureus.

Yan, Meiying; Yu, Chuanxin; Yang, Junshu; Ji, Yinduo

2009-01-01

151

Inhibitory effects of Satureja hortensis L. essential oil on growth and aflatoxin production by Aspergillus parasiticus  

Microsoft Academic Search

In an effort to screen the essential oils of some Iranian medicinal plants for novel aflatoxin (AF) inhibitors, Satureja hortensis L. was found as a potent inhibitor of aflatoxins B1 (AFB1) and G1(AFG1) production by Aspergillus parasiticus NRRL 2999. Fungal growth was also inhibited in a dose-dependent manner. Separation of the plant inhibitory substance(s) was achieved using initial fractionation of

Mehdi Razzaghi-Abyaneh; Masoomeh Shams-Ghahfarokhi; Tomoya Yoshinari; Mohammad-Bagher Rezaee; Kamkar Jaimand; Hiromichi Nagasawa; Shohei Sakuda

2008-01-01

152

Small genes/gene-products in Escherichia coli K-12.  

PubMed

Forty-two protein spots of observed M(r) 6-15 kDa were resolved by two-dimensional gel electrophoresis, stained by Coomassie blue and subjected to Edman microsequencing. All of the proteins could be related back to their encoding open reading frames, thereby vindicating the bioinformatic tools currently utilised in their identification. However, only 14/42 gene-products were expressed as annotated. Translation was confirmed for 14 open reading frames with no attributed function (EcoGene Y-entries), while N-terminal sequence allowed the start codon to be accurately annotated for the genes yigF, yccU, yqiC, ynfD, and yeeX. The methionine start codon was cleaved in 11 gene-products (AtpE, Hns, RpoZ, RplL, CspC, YccJ, YggX, YjgF, HimA, InfA, RpsQ) and a further five showed loss of a signal peptide (PspE, HdeB, HdeA, YnfD, YkfE). Internal (Tig, AtpA, TufA) and N-terminal fragmentation (CspD, RpsF, AtcU) of much larger proteins was also detected, which may have resulted from physiological or translational processes. M(r) and pI isoforms were detected respectively for PtsH and GatB, each being phosphoproteins, as well as RplY which manifested differences with respect to predicted M(r) and pI. In addition, YjgF was shown to belong to a small gene family of unknown function with ancient conserved regions across procaryotes and eucaryotes. YgiN was revealed to have a paralogue and orthologues in Bacillus subtilis, Synechocystis sp., Mycobacterium tuberculosis, Neisseria gonorrhoea, and Rhodococcus erythropolis. Orthologues are also reported for YihD, YccU and YeeX. Of the 14 Y-genes, only YkfE possessed no detectable orthologues. These results highlight the need to complement genomic analysis with detailed proteomics in order to gain a better understanding of cellular molecular biology, while the confirmation of the open reading frame start codon using Edman degradation protein microsequencing has yet to be superseded by recent advances in mass spectrometry. PMID:9868784

Wasinger, V C; Humphery-Smith, I

1998-12-15

153

BIOMED-2 PCR assays for IGK gene rearrangements are essential for B-cell clonality analysis in follicular lymphoma.  

PubMed

B-cell clonality analysis is commonly performed by polymerase chain reaction (PCR) targeting the IGH genes although a high false-negative rate is recognized for germinal centre/post-germinal centre B-cell malignancies, especially follicular lymphoma. We assessed the diagnostic value of BIOMED-2 IGK assays and investigated the cause of IGH PCR failure in 77 patients with follicular lymphoma. Using the full set of BIOMED-2 reactions, clonal immunoglobulin gene rearrangements were detected in 74 (96%) cases. The clonality detection rate was 86% by two IGK reactions but only 68% by five IGH reactions (P?products showed significantly fewer somatic mutations in the rearranged IGKV (9/27 cases, 33%, mean mutation rate 0·5%) than IGHV (17/17 cases, 100%, rate 11·0%) (P?essential in routine clonality analysis of these lymphomas. PMID:21790530

Payne, Karen; Wright, Penny; Grant, John W; Huang, Yuanxue; Hamoudi, Rifat; Bacon, Chris M; Du, Ming-Qing; Liu, Hongxiang

2011-10-01

154

Mesp2: a novel mouse gene expressed in the presegmented mesoderm and essential for segmentation initiation.  

PubMed

We isolated a novel bHLH protein gene Mesp2 (for mesoderm posterior 2) that cross-hybridizes with Mesp1 expressed in the early mouse mesoderm. Mesp2 is expressed in the rostral presomitic mesoderm, but down-regulated immediately after the formation of the segmented somites. To determine the function of MesP2 protein (MesP2) in somitogenesis, we generated Mesp2-deficient mice by gene targeting. The homozygous Mesp2 (-/-) mice died shortly after birth and had fused vertebral columns and dorsal root ganglia, with impaired sclerotomal polarity. The earliest defect in the homozygous embryos was a lack of segmented somites. Their disruption of the metameric features, altered expression of Mox-1, Pax-1, and Dll1, and lack of expression of Notch1, Notch2, and FGFR1 suggested that MesP2 controls sclerotomal polarity by regulating the signaling systems mediated by notch-delta and FGF, which are essential for segmentation. PMID:9242490

Saga, Y; Hata, N; Koseki, H; Taketo, M M

1997-07-15

155

E-Selectin Gene Polymorphisms and Essential Hypertension in Asian Population: An Updated Meta-Analysis  

PubMed Central

Objective Epidemiological studies have shown that E-selectin gene polymorphisms (A561C and C1839T) may be associated with essential hypertension (EH), but the results are conflicting in different ethnic populations. Thus, we performed this meta-analysis to investigate a more authentic association between E-selectin gene polymorphisms and the risk of EH. Methods We searched the relevant studies for the present meta-analysis from the following electronic databases: PubMed, Embase, Cochrane Library, Google Scholar, Web of Science, Wanfang Data, and China National Knowledge Infrastructure (CNKI). Odds ratios (OR) with 95% confidence interval (CI) were used to evaluate the strength of the association between E-selectin gene polymorphisms and EH susceptibility. The pooled ORs were performed for dominant model, allelic model and recessive model. The publication bias was examined by Begg’s funnel plots and Egger’s test. Results A total of eleven studies met the inclusion criteria. All studies came from Asians. Ten studies (12 cohorts) evaluated the A561C polymorphism and EH risk, including 2,813 cases and 2,817 controls. The pooled OR was 2.280 (95%CI: 1.893–2.748, P<0.001) in dominant model, 5.284 (95%CI: 2.679–10.420, P<0.001) in recessive model and 2.359 (95%CI: 1.981–2.808, P?=?0.001) in allelic model. Four studies (six cohorts) evaluated C1839T polymorphism and EH risk, including 1,700 cases and 1,681 controls. The pooled OR was 0.785 (95%CI: 0.627–0.983, P?=?0.035) in dominant model, 1.250 (95%CI: 0.336–4.652, P?=?0.739) in recessive model and 0.805 (95%CI: 0.649–0.999, P?=?0.049) in allelic model. Conclusion The current meta-analysis concludes that the C allele of E-selectin A561C gene polymorphism might increase the EH risk in Asian population, whereas the T allele of E-selectin C1839T gene polymorphism might decrease the EH risk.

Cai, Gaojun; Zhang, Bifeng; Weng, Weijin; Shi, Ganwei; Xue, Sheliang; Song, Yanbin; Ma, Chunyan

2014-01-01

156

Conserved and essential transcription factors for cellulase gene expression in ascomycete fungi.  

PubMed

Rational engineering of filamentous fungi for improved cellulase production is hampered by our incomplete knowledge of transcriptional regulatory networks. We therefore used the model filamentous fungus Neurospora crassa to search for uncharacterized transcription factors associated with cellulose deconstruction. A screen of a N. crassa transcription factor deletion collection identified two uncharacterized zinc binuclear cluster transcription factors (clr-1 and clr-2) that were required for growth and enzymatic activity on cellulose, but were not required for growth or hemicellulase activity on xylan. Transcriptional profiling with next-generation sequencing methods refined our understanding of the N. crassa transcriptional response to cellulose and demonstrated that clr-1 and clr-2 were required for the bulk of that response, including induction of all major cellulase and some major hemicellulase genes. Functional CLR-1 was necessary for expression of clr-2 and efficient cellobiose utilization. Phylogenetic analyses showed that CLR-1 and CLR-2 are conserved in the genomes of most filamentous ascomycete fungi capable of degrading cellulose. In Aspergillus nidulans, a strain carrying a deletion of the clr-2 homolog (clrB) failed to induce cellulase gene expression and lacked cellulolytic activity on Avicel. Further manipulation of this control system in industrial production strains may significantly improve yields of cellulases for cellulosic biofuel production. PMID:22532664

Coradetti, Samuel T; Craig, James P; Xiong, Yi; Shock, Teresa; Tian, Chaoguang; Glass, N Louise

2012-05-01

157

Bifunctional Gene Cluster lnqBCDEF Mediates Bacteriocin Production and Immunity with Differential Genetic Requirements  

PubMed Central

A comprehensive gene disruption of lacticin Q biosynthetic cluster lnqQBCDEF was carried out. The results demonstrated the necessity of the complete set of lnqQBCDEF for lacticin Q production, whereas immunity was flexible, with LnqEF (ABC transporter) being essential for and LnqBCD partially contributing to immunity.

Iwatani, Shun; Horikiri, Yuko; Zendo, Takeshi; Nakayama, Jiro

2013-01-01

158

Gender specific association of RAS gene polymorphism with essential hypertension: a case-control study.  

PubMed

Renin-angiotensin system (RAS) polymorphisms have been studied as candidate risk factors for hypertension with inconsistent results, possibly due to heterogeneity among various genetic and environmental factors. A case-control association study was conducted to investigate a possible involvement of polymorphisms of three RAS genes: AGT M235T (rs699), ACE I/D (rs4340) and G2350A (rs4343), and AGTR1 A1166C (rs5186) in essential hypertensive patients. A total of 211 cases and 211 controls were recruited for this study. Genotyping was performed using PCR-RFLP method. The genotype and allele distribution of the M235T variant differed significantly in hypertensives and normotensives (OR-CI = 2.62 (1.24-5.76), P = 0.006; OR-CI = 0.699 (0.518-0.943), P = 0.018), respectively. When the samples were segregated based on sex, the 235TT genotype and T allele were predominant in the female patients (OR-CI = 5.68 (1.60-25.10), P = 0.002; OR-CI = 0.522 (0.330-0.826), P = 0.005) as compare to the male patients (OR-CI = 1.54 (1.24-5.76), P = 0.34; OR-CI = 0.874 (0.330-0.826), P = 0.506), respectively. For ACE DD variant, we found overrepresentation of "I"-allele (homozygous II and heterozygous ID) in unaffected males which suggest its protective role in studied population (OR-CI = 0.401 (0.224-0.718); P = 0.0009). The M235T variant of the AGT is significantly associated with female hypertensives and ACE DD variant could be a risk allele for essential hypertension in south India. PMID:24860821

Dhanachandra Singh, Kh; Jajodia, Ajay; Kaur, Harpreet; Kukreti, Ritushree; Karthikeyan, Muthusamy

2014-01-01

159

MHP1, an essential gene in Saccharomyces cerevisiae required for microtubule function  

PubMed Central

The gene for a microtubule-associated protein (MAP), termed MHP1 (MAP- Homologous Protein 1), was isolated from Saccharomyces cerevisiae by expression cloning using antibodies specific for the Drosophila 205K MAP. MHP1 encodes an essential protein of 1,398 amino acids that contains near its COOH-terminal end a sequence homologous to the microtubule-binding domain of MAP2, MAP4, and tau. While total disruptions are lethal, NH2-terminal deletion mutations of MHP1 are viable, and the expression of the COOH-terminal two-thirds of the protein is sufficient for vegetative growth. Nonviable deletion- disruption mutations of MHP1 can be partially complemented by the expression of the Drosophila 205K MAP. Mhp1p binds to microtubules in vitro, and it is the COOH-terminal region containing the tau-homologous motif that mediates microtubule binding. Antibodies directed against a COOH-terminal peptide of Mhp1p decorate cytoplasmic microtubules and mitotic spindles as revealed by immunofluorescence microscopy. The overexpression of an NH2-terminal deletion mutation of MHP1 results in an accumulation of large-budded cells with short spindles and disturbed nuclear migration. In asynchronously growing cells that overexpress MHP1 from a multicopy plasmid, the length and number of cytoplasmic microtubules is increased and the proportion of mitotic cells is decreased, while haploid cells in which the expression of MHP1 has been silenced exhibit few microtubules. These results suggest that MHP1 is essential for the formation and/or stabilization of microtubules.

1996-01-01

160

Gender Specific Association of RAS Gene Polymorphism with Essential Hypertension: A Case-Control Study  

PubMed Central

Renin-angiotensin system (RAS) polymorphisms have been studied as candidate risk factors for hypertension with inconsistent results, possibly due to heterogeneity among various genetic and environmental factors. A case-control association study was conducted to investigate a possible involvement of polymorphisms of three RAS genes: AGT M235T (rs699), ACE I/D (rs4340) and G2350A (rs4343), and AGTR1 A1166C (rs5186) in essential hypertensive patients. A total of 211 cases and 211 controls were recruited for this study. Genotyping was performed using PCR-RFLP method. The genotype and allele distribution of the M235T variant differed significantly in hypertensives and normotensives (OR-CI = 2.62 (1.24–5.76), P = 0.006; OR-CI = 0.699 (0.518–0.943), P = 0.018), respectively. When the samples were segregated based on sex, the 235TT genotype and T allele were predominant in the female patients (OR-CI = 5.68 (1.60-25.10), P = 0.002; OR-CI = 0.522 (0.330–0.826), P = 0.005) as compare to the male patients (OR-CI = 1.54 (1.24–5.76), P = 0.34; OR-CI = 0.874 (0.330–0.826), P = 0.506), respectively. For ACE DD variant, we found overrepresentation of “I”-allele (homozygous II and heterozygous ID) in unaffected males which suggest its protective role in studied population (OR-CI = 0.401 (0.224–0.718); P = 0.0009). The M235T variant of the AGT is significantly associated with female hypertensives and ACE DD variant could be a risk allele for essential hypertension in south India.

Dhanachandra Singh, Kh.; Jajodia, Ajay; Kaur, Harpreet; Kukreti, Ritushree; Karthikeyan, Muthusamy

2014-01-01

161

Drosophila Homologue of the Rothmund-Thomson Syndrome Gene: Essential Function in DNA Replication During Development  

PubMed Central

Summary Members of the RecQ family play critical roles in maintaining genome integrity. Mutations in human RecQL4 cause a rare genetic disorder, Rothmund-Thomson syndrome. Transgenic mice experiments showed that the RecQ4 null mutant causes embryonic lethality. Although biochemical evidence suggests that the Xenopus RecQ4 is required for the initiation of DNA replication in the oocyte extract, its biological functions during development remain to be elucidated. We present here our results in establishing the use of Drosophila as a model system to probe RecQ4 functions. Immunofluorescence experiments monitoring the cellular distribution of RecQ4 demonstrated that RecQ4 expression peaks during S phase, and RecQ4 is expressed only in tissues active in DNA replication, but not in quiescent cells. We have isolated Drosophila RecQ4 hypomorphic mutants, recqEP and recq423, which specifically reduce chorion gene amplification of follicle cells by 4–5 fold, resulting in thin and fragile eggshells, and female sterility. Quantitative analysis on amplification defects over a 14-kb domain in chorion gene cluster suggests that RecQ4 may have a specific function at or near the origin of replication. A null allele recq419 causes a failure in cell proliferation, decrease in DNA replication, chromosomal fragmentation, and lethality at the stage of first instar larvae. The mosaic analysis indicates that cell clones with homozygous recq419 fail to proliferate. These results indicate that RecQ4 is essential for viability and fertility, and is required for most aspects of DNA replication during development.

Wu, Jianhong; Capp, Christopher; Feng, Liping; Hsieh, Tao-shih

2008-01-01

162

Use of targetrons to disrupt essential and nonessential genes in Staphylococcus aureus reveals temperature sensitivity of Ll.LtrB group II intron splicing  

PubMed Central

We show that a targetron based on the Lactococcus lactis Ll.LtrB group II intron can be used for efficient chromosomal gene disruption in the human pathogen Staphylococcus aureus. Targetrons expressed from derivatives of vector pCN37, which uses a cadmium-inducible promoter, or pCN39, a derivative of pCN37 with a temperature-sensitive replicon, gave site-specific disruptants of the hsa and seb genes in 37%–100% of plated colonies without selection. To disrupt hsa, an essential gene, we used a group II intron that integrates in the sense orientation relative to target gene transcription and thus could be removed by RNA splicing, enabling the production of functional HSa protein. We show that because splicing of the Ll.LtrB intron by the intron-encoded protein is temperature-sensitive, this method yields a conditional hsa disruptant that grows at 32°C but not 43°C. The temperature sensitivity of the splicing reaction suggests a general means of obtaining one-step conditional disruptions in any organism. In nature, temperature sensitivity of group II intron splicing could limit the temperature range of an organism containing a group II intron inserted in an essential gene.

Yao, Jun; Zhong, Jin; Fang, Yuan; Geisinger, Edward; Novick, Richard P.; Lambowitz, Alan M.

2006-01-01

163

Varicella-Zoster Virus ORF49 Functions in the Efficient Production of Progeny Virus through Its Interaction with Essential Tegument Protein ORF44  

PubMed Central

The ORF49 tegument protein of varicella-zoster virus (VZV) is one of the core gene products that is conserved among herpesvirus family members. Although ORF49 is known to be a cell-tropic factor, its detailed functions remain elusive. ORF44 is another core gene product reported to be essential, although its characterization and detailed functional analysis have not been reported. These two core gene products form a complex in other herpesviruses beyond the host species and herpesvirus subfamilies. Here, we show that complex formation between ORF44 and ORF49 is conserved in VZV. We serendipitously found that binding is eliminated by an amino acid substitution at position 129 (phenylalanine 129), and four amino acids in the carboxyl-terminal half of the acidic cluster in ORF49 (i.e., aspartate-phenylalanine-aspartate-glutamate from positions 41 to 44 [41DFDE44]) were identified as its binding motif. Alanine substitutions in each domain rendered the ORF44F129A mutation lethal for VZV, similar to deletion of the entire ORF44. The phenotype of the ORF49-41AAAA44 mutation was comparable to that of the ORF49-defective virus, including small-plaque formation, impaired growth, and low infectious virus production. These results suggest that the interaction between ORF44 and ORF49 is essential for their role in VZV infection and that ORF49 is required for the efficient production of infectious progeny virus mediated by the conserved interaction between the two proteins.

Sadaoka, Tomohiko; Serada, Satoshi; Kato, Junko; Hayashi, Mayuko; Gomi, Yasuyuki; Naka, Tetsuji; Yamanishi, Koichi

2014-01-01

164

Effects of Herbal Essential Oil Mixture as a Dietary Supplement on Egg Production in Quail  

PubMed Central

One hundred and eighty 7-week-old laying quail were fed various diets over a 12-week period. The diets included a control diet (without essential oil mixture (EOM) or antibiotics (ANTs)), a basal diet including EOM (24?mg/kg feed), and a basal diet including an ANT (avilamycin, 10?mg/kg feed). Each treatment comprised 4 replications with 4 cages (15 quail per cage), amounting to 60 quail per treatment group. Diets (in mash form) and water were provided for ad libitum consumption. EOM consisted of 6 different essential oils derived from the following herbs: oregano (Origanum sp.), laurel leaf (Laurus nobilis L.), sage leaf (Salvia triloba L.), myrtle leaf (Myrtus communis), fennel seeds (Foeniculum vulgare), and citrus peel (Citrus sp.). In comparison with the control diet, adding supplements such as EOM and ANTs to the basal diet increased egg production in quail (P < 0.001). However, egg production was similar between EOM and ANT treatment groups. Moreover, there were no differences between the treatment groups with regard to egg weight. Feed intake was not affected by EOM or ANT supplementation, whereas feed conversion ratio was significantly improved by EOM and ANT supplementation. Thus, we concluded that EOM has beneficial effects as a dietary supplement on egg production and feed conversion ratio.

Cabuk, Metin; Eratak, Serdar; Alcicek, Ahmet; Bozkurt, Mehmet

2014-01-01

165

Effects of herbal essential oil mixture as a dietary supplement on egg production in quail.  

PubMed

One hundred and eighty 7-week-old laying quail were fed various diets over a 12-week period. The diets included a control diet (without essential oil mixture (EOM) or antibiotics (ANTs)), a basal diet including EOM (24?mg/kg feed), and a basal diet including an ANT (avilamycin, 10?mg/kg feed). Each treatment comprised 4 replications with 4 cages (15 quail per cage), amounting to 60 quail per treatment group. Diets (in mash form) and water were provided for ad libitum consumption. EOM consisted of 6 different essential oils derived from the following herbs: oregano (Origanum sp.), laurel leaf (Laurus nobilis L.), sage leaf (Salvia triloba L.), myrtle leaf (Myrtus communis), fennel seeds (Foeniculum vulgare), and citrus peel (Citrus sp.). In comparison with the control diet, adding supplements such as EOM and ANTs to the basal diet increased egg production in quail (P < 0.001). However, egg production was similar between EOM and ANT treatment groups. Moreover, there were no differences between the treatment groups with regard to egg weight. Feed intake was not affected by EOM or ANT supplementation, whereas feed conversion ratio was significantly improved by EOM and ANT supplementation. Thus, we concluded that EOM has beneficial effects as a dietary supplement on egg production and feed conversion ratio. PMID:24587729

Çabuk, Metin; Eratak, Serdar; Alçicek, Ahmet; Bozkurt, Mehmet

2014-01-01

166

Vaccinia virus gene A18R encodes an essential DNA helicase.  

PubMed Central

The vaccinia virus A18R protein is a DNA-dependent ATPase that contains the canonical sequence motifs associated with the DEXH group of DNA and RNA helicases. Investigation of A18R protein function during infection indicated it functions in the early and late phases of vaccinia virus transcription. The A18R protein shares sequence similarity with the mammalian DNA helicase ERCC3. The ERCC3 protein has a dual function: it is a component of the transcription factor TFIIH and is an essential participant in the cellular nucleotide excision repair pathway. Here we present evidence that the A18R protein is a DNA helicase that unwinds duplex DNA in a 3'-to-5' direction. The A18R helicase was inactive on RNA-DNA and RNA-RNA hybrids. The A18R unwinding activity was most efficient on DNA substrates with lengths of 20 nucleotides or less, and its unwinding activity was not stimulated by the addition of Escherichia coli single-strand-binding protein (SSB), the bacteriophage T4 gene 32 SSB, or the vaccinia virus I3L protein, a putative SSB. We have used an electrophoretic gel mobility shift assay to show that the A18R protein forms a stable complex with single-stranded DNA, and to a lesser extent RNA, in a reaction that does not require ATP.

Simpson, D A; Condit, R C

1995-01-01

167

TSHZ1-dependent gene regulation is essential for olfactory bulb development and olfaction.  

PubMed

The olfactory bulb (OB) receives odor information from the olfactory epithelium and relays this to the olfactory cortex. Using a mouse model, we found that development and maturation of OB interneurons depends on the zinc finger homeodomain factor teashirt zinc finger family member 1 (TSHZ1). In mice lacking TSHZ1, neuroblasts exhibited a normal tangential migration to the OB; however, upon arrival to the OB, the neuroblasts were distributed aberrantly within the radial dimension, and many immature neuroblasts failed to exit the rostral migratory stream. Conditional deletion of Tshz1 in mice resulted in OB hypoplasia and severe olfactory deficits. We therefore investigated olfaction in human subjects from families with congenital aural atresia that were heterozygous for TSHZ1 loss-of-function mutations. These individuals displayed hyposmia, which is characterized by impaired odor discrimination and reduced olfactory sensitivity. Microarray analysis, in situ hybridization, and ChIP revealed that TSHZ1 bound to and regulated expression of the gene encoding prokineticin receptor 2 (PROKR2), a G protein–coupled receptor essential for OB development. Mutations in PROKR2 lead to Kallmann syndrome, characterized by anosmia and hypogonadotrophic hypogonadism. Our data indicate that TSHZ1 is a key regulator of mammalian OB development and function and controls the expression of molecules involved in human Kallmann syndrome. PMID:24487590

Ragancokova, Daniela; Rocca, Elena; Oonk, Anne M M; Schulz, Herbert; Rohde, Elvira; Bednarsch, Jan; Feenstra, Ilse; Pennings, Ronald J E; Wende, Hagen; Garratt, Alistair N

2014-03-01

168

The RNase III Enzyme DROSHA Is Essential for MicroRNA Production and Spermatogenesis*  

PubMed Central

DROSHA is a nuclear RNase III enzyme responsible for cleaving primary microRNAs (miRNAs) into precursor miRNAs and thus is essential for the biogenesis of canonical miRNAs. DICER is a cytoplasmic RNase III enzyme that not only cleaves precursor miRNAs to produce mature miRNAs but also dissects naturally formed/synthetic double-stranded RNAs to generate small interfering RNAs (siRNAs). To investigate the role of canonical miRNA and/or endogenous siRNA production in spermatogenesis, we generated Drosha or Dicer conditional knock-out (cKO) mouse lines by inactivating Drosha or Dicer exclusively in spermatogenic cells in postnatal testes using the Cre-loxp strategy. Both Drosha and Dicer cKO males were infertile due to disrupted spermatogenesis characterized by depletion of spermatocytes and spermatids leading to oligoteratozoospermia or azoospermia. The developmental course of spermatogenic disruptions was similar at morphological levels between Drosha and Dicer cKO males, but Drosha cKO testes appeared to be more severe in spermatogenic disruptions than Dicer cKO testes. Microarray analyses revealed transcriptomic differences between Drosha- and Dicer-null pachytene spermatocytes or round spermatids. Although levels of sex-linked mRNAs were mildly elevated, meiotic sex chromosome inactivation appeared to have occurred normally. Our data demonstrate that unlike DICER, which is required for the biogenesis of several small RNA species, DROSHA is essential mainly for the canonical miRNA production, and DROSHA-mediated miRNA production is essential for normal spermatogenesis and male fertility.

Wu, Qiuxia; Song, Rui; Ortogero, Nicole; Zheng, Huili; Evanoff, Ryan; Small, Chris L.; Griswold, Michael D.; Namekawa, Satoshi H.; Royo, Helene; Turner, James M.; Yan, Wei

2012-01-01

169

The Coactivator SRC-1 is an Essential Coordinator of Hepatic Glucose Production  

PubMed Central

Gluconeogenesis makes a major contribution to hepatic glucose production, a process critical for survival in mammals. In this study, we identify the p160 family member, SRC-1, as a key coordinator of the hepatic gluconeogenic program in vivo. SRC-1 null mice displayed hypoglycemia secondary to a deficit in hepatic glucose production. Selective re-expression of SRC-1 in the liver restored blood glucose levels to a normal range. SRC-1 was found induced upon fasting to coordinate in a cell-autonomous manner, the gene expression of rate-limiting enzymes of the gluconeogenic pathway. At the molecular level, the main role of SRC-1 was to modulate the expression and the activity of C/EBP? through a feed-forward loop in which SRC-1 used C/EBP? to transactivate pyruvate carboxylase, a crucial gene for initiation of the gluconeogenic program. We propose that SRC-1, acts as a novel and critical mediator of glucose homeostasis in the liver by adjusting the transcriptional activity of key genes involved in the hepatic glucose production machinery.

Louet, Jean-Francois; Chopra, Atul R.; Sagen, Jorn V.; An, Jie; York, Brian; Tannour-Louet, Mounia; Saha, Pradip K.; Stevens, Robert D.; Wenner, Brett R.; Ilkayeva, Olga R.; Bain, James R.; Zhou, Suoling; DeMayo, Franco; Xu, Jianming; Newgard, Christopher B.; O'Malley, Bert W.

2010-01-01

170

The Hansenula polymorpha PEX14 gene encodes a novel peroxisomal membrane protein essential for peroxisome biogenesis.  

PubMed Central

We have cloned the Hansenula polymorpha PEX14 gene by functional complementation of the chemically induced pex14-1 mutant, which lacked normal peroxisomes. The sequence of the PEX14 gene predicts a novel protein product (Pex14p) of 39 kDa which showed no similarity to any known protein and lacked either of the two known peroxisomal targeting signals. Biochemical and electron microscopical analysis indicated that Pex14p is a component of the peroxisomal membrane. The synthesis of Pex14p is induced by peroxisome-inducing growth conditions. In cells of both pex14-1 and a PEX14 disruption mutant, peroxisomal membrane remnants were evident; these contained the H.polymorpha peroxisomal membrane protein Pex3p together with a small amount of the major peroxisomal matrix proteins alcohol oxidase, catalase and dihydroxyacetone synthase, the bulk of which resided in the cytosol. Unexpectedly, overproduction of Pex14p in wild-type H. polymorpha cells resulted in a peroxisome-deficient phenotype typified by the presence of numerous small vesicles which lacked matrix proteins; these were localized in the cytosol. Apparently, the stoichiometry of Pex14p relative to one or more other components of the peroxisome biogenesis machinery appears to be critical for protein import.

Komori, M; Rasmussen, S W; Kiel, J A; Baerends, R J; Cregg, J M; van der Klei, I J; Veenhuis, M

1997-01-01

171

ROS Production Is Essential for the Apoptotic Function of E2F1 in Pheochromocytoma and Neuroblastoma Cell Lines  

PubMed Central

In this study we demonstrate that accumulation of reactive oxygen species (ROS) is essential for E2F1 mediated apoptosis in ER-E2F1 PC12 pheochromocytoma, and SH-SY5Y and SK-N-JD neuroblastoma stable cell lines. In these cells, the ER-E2F1 fusion protein is expressed in the cytosol; the addition of 4-hydroxytamoxifen (OHT) induces its translocation to the nucleus and activation of E2F1target genes. Previously we demonstrated that, in ER-E2F1 PC12 cells, OHT treatment induced apoptosis through activation of caspase-3. Here we show that caspase-8 activity did not change upon treatment with OHT. Moreover, over-expression of Bcl-xL arrested OHT-induced apoptosis; by contrast, over-expression of c-FLIP, did not have any effect on OHT-induced apoptosis. OHT addition induces BimL expression, its translocation to mitochondria and activation of Bax, which is paralleled by diminished mitochondrial enrichment of Bcl-xL. Treatment with a Bax-inhibitory peptide reduced OHT-induced apoptosis. These results point out the essential role of mitochondria on the apoptotic process driven by E2F1. ROS accumulation followed E2F1 induction and treatment with the antioxidant N-acetylcysteine, inhibited E2F1-induced Bax translocation to mitochondria and subsequent apoptosis. The role of ROS in mediating OHT-induced apoptosis was also studied in two neuroblastoma cell lines, SH-SY5Y and SK-N-JD. In SH-SY5Y cells, activation of E2F1 by the addition of OHT induced ROS production and apoptosis, whereas over-expression of E2F1 in SK-N-JD cells failed to induce either response. Transcriptional profiling revealed that many of the genes responsible for scavenging ROS were down-regulated following E2F1-induction in SH-SY5Y, but not in SK-N-JD cells. Finally, inhibition of GSK3? blocked ROS production, Bax activation and the down regulation of ROS scavenging genes. These findings provide an explanation for the apparent contradictory role of E2F1 as an apoptotic agent versus a cell cycle activator.

Espada, Lilia; Meo-Evoli, Nathalie; Sancho, Patricia; Real, Sebastian; Fabregat, Isabel; Ambrosio, Santiago; Tauler, Albert

2012-01-01

172

The Autographa californica multiple nucleopolyhedrovirus ORF78 is essential for budded virus production and general occlusion body formation.  

PubMed

ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in the baculovirus life cycle, an AcMNPV mutant with ac78 deleted, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype, indicating that no infectious budded viruses (BVs) were produced. The defect in BV production was also confirmed by both viral titration and Western blotting. However, viral DNA replication was unaffected, and occlusion bodies were formed. An analysis of BVs and occlusion-derived viruses (ODVs) revealed that AC78 is associated with both forms of the virions and is an envelope structural protein. Electron microscopy revealed that AC78 also plays an important role in the embedding of ODV into the occlusion body. The results of this study demonstrate that AC78 is a late virion-associated protein and is essential for the viral life cycle. PMID:23698311

Tao, Xue Ying; Choi, Jae Young; Kim, Woo Jin; Lee, Joo Hyun; Liu, Qin; Kim, Song Eun; An, Saes Byeol; Lee, Seok Hee; Woo, Soo Dong; Jin, Byung Rae; Je, Yeon Ho

2013-08-01

173

The Autographa californica Multiple Nucleopolyhedrovirus ORF78 Is Essential for Budded Virus Production and General Occlusion Body Formation  

PubMed Central

ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in the baculovirus life cycle, an AcMNPV mutant with ac78 deleted, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype, indicating that no infectious budded viruses (BVs) were produced. The defect in BV production was also confirmed by both viral titration and Western blotting. However, viral DNA replication was unaffected, and occlusion bodies were formed. An analysis of BVs and occlusion-derived viruses (ODVs) revealed that AC78 is associated with both forms of the virions and is an envelope structural protein. Electron microscopy revealed that AC78 also plays an important role in the embedding of ODV into the occlusion body. The results of this study demonstrate that AC78 is a late virion-associated protein and is essential for the viral life cycle.

Tao, Xue Ying; Choi, Jae Young; Kim, Woo Jin; Lee, Joo Hyun; Liu, Qin; Kim, Song Eun; An, Saes Byeol; Lee, Seok Hee; Woo, Soo Dong; Jin, Byung Rae

2013-01-01

174

Integrating the Genetic and Physical Maps of Arabidopsis thaliana: Identification of Mapped Alleles of Cloned Essential (EMB) Genes  

PubMed Central

The classical genetic map of Arabidopsis includes more than 130 genes with an embryo-defective (emb) mutant phenotype. Many of these essential genes remain to be cloned. Hundreds of additional EMB genes have been cloned and catalogued (www.seedgenes.org) but not mapped. To facilitate EMB gene identification and assess the current level of saturation, we updated the classical map, compared the physical and genetic locations of mapped loci, and performed allelism tests between mapped (but not cloned) and cloned (but not mapped) emb mutants with similar chromosome locations. Two hundred pairwise combinations of genes located on chromosomes 1 and 5 were tested and more than 1100 total crosses were screened. Sixteen of 51 mapped emb mutants examined were found to be disrupted in a known EMB gene. Alleles of a wide range of published EMB genes (YDA, GLA1, TIL1, AtASP38, AtDEK1, EMB506, DG1, OEP80) were discovered. Two EMS mutants isolated 30 years ago, T-DNA mutants with complex insertion sites, and a mutant with an atypical, embryo-specific phenotype were resolved. The frequency of allelism encountered was consistent with past estimates of 500 to 1000 EMB loci. New EMB genes identified among mapped T-DNA insertion mutants included CHC1, which is required for chromatin remodeling, and SHS1/AtBT1, which encodes a plastidial nucleotide transporter similar to the maize Brittle1 protein required for normal endosperm development. Two classical genetic markers (PY, ALB1) were identified based on similar map locations of known genes required for thiamine (THIC) and chlorophyll (PDE166) biosynthesis. The alignment of genetic and physical maps presented here should facilitate the continued analysis of essential genes in Arabidopsis and further characterization of a broad spectrum of mutant phenotypes in a model plant.

Meinke, David; Sweeney, Colleen; Muralla, Rosanna

2009-01-01

175

Effect of Zingiber officinale essential oil on Fusarium verticillioides and fumonisin production.  

PubMed

The antifungal activity of ginger essential oil (GEO; Zingiber officinale Roscoe) was evaluated against Fusarium verticillioides (Saccardo) Nirenberg. The minimum inhibitory concentration (MIC) of GEO was determined by micro-broth dilution. The effects of GEO on fumonisin and ergosterol production were evaluated at concentrations of 500-5000 ?g/mL in liquid medium with a 5mm diameter mycelial disc of F. verticillioides. Gas chromatography-mass spectrometry showed that the predominant components of GEO were ?-zingiberene (23.9%) and citral (21.7%). GEO exhibited inhibitory activity, with a MIC of 2500 ?g/mL, and 4000 and 5000 ?g/mL reduced ergosterol biosynthesis by 57% and 100%, respectively. The inhibitory effect on fumonisin B1 (FB1) and fumonisin B2 (FB2) production was significant at GEO concentrations of 4000 and 2000 ?g/mL, respectively. Thus, the inhibition of fungal biomass and fumonisin production was dependent on the concentration of GEO. These results suggest that GEO was able to control the growth of F. verticillioides and subsequent fumonisin production. PMID:23871071

Yamamoto-Ribeiro, Milene Mayumi Garcia; Grespan, Renata; Kohiyama, Cássia Yumie; Ferreira, Flavio Dias; Mossini, Simone Aparecida Galerani; Silva, Expedito Leite; Filho, Benicio Alves de Abreu; Mikcha, Jane Martha Graton; Machinski, Miguel

2013-12-01

176

Processing of Vietnamese Essential Oils and Related Natural Products, Viet Nam. Technical Report: Findings, Work Performed and Recommendations.  

National Technical Information Service (NTIS)

The report focuses on the processing of essential oils and related natural products in Vietnam. It covers: a national workshop on development of local expertise in odor evaluation; perfumes; the use of locally available raw materials; definitions of fragr...

S. Jain

1990-01-01

177

Influence of Origanum vulgare L. essential oil on enterotoxin production, membrane permeability and surface characteristics of Staphylococcus aureus  

Microsoft Academic Search

This study evaluated the influence of the essential oil from Origanum vulgare L. on the enterotoxin production, membrane permeability and cell surface characteristics of Staphylococcus aureus. The suppression of enterotoxin production occurred totally in the broth added with the essential oil at subinhibitory concentrations (0.3 and 0.15µL\\/mL). Loss of 260-nm-absorbing material and potassium ions occurred immediately after addition of the

Evandro Leite de Souza; Jefferson Carneiro de Barros; Carlos Eduardo Vasconcelos de Oliveira; Maria Lúcia da Conceição

2010-01-01

178

?-Adducin gene G614T polymorphisms in essential hypertension patients with high low density lipoprotein (LDL) levels  

PubMed Central

Background & objectives: The association between ?-adducin gene G614T polymorphism and essential hypertension (EH) is not clear. The present study was carried out to examine a possible association between ?-adducin gene G614T mutation and essential hypertension in Chinese population. Methods: A total of 170 patients with essential hypertension (EH group) and 154 normotensive subjects (Control group) were genotyped for the cytoskeletal protein single nucleotide polymorphism G614T of the ?-adducin gene by PCR-RFLP technique. Systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), low density lipoprotein (LDL), high-density lipoprotein (HDL), high-sensitivity C-reactive protein (hs-CRP), left atrial diameter (LA DIA), left ventricular diameter (LV DIA) and other parameters were recorded in EH group. Results: There was significant association between EH and ?-adducin genotypes (P<0.05). GT and TT genotypes in EH group had higher LDL levels as compared to GG carriers (P<0.05). The LDL concentration was significantly elevated in patients with GT and TT genotypes. The LDL levels also differed significantly in male patients with all the three genotypes. Interpretation & conclusions: A significant association was found between ADD1 gene G614T polymorphism and EH in Chinese patients. Further studies need to be done to confirm these findings in a large sample.

Wang, Lifang; Zheng, Bin; Zhao, Hongguang; Du, Peng; Sun, Aihua; Hua, Kouzhen; Gao, Yuyu

2014-01-01

179

The splice leader addition domain represents an essential conserved motif for heterologous gene expression in B. malayi  

PubMed Central

Two promoters from the human filarial parasite Brugia malayi have been mapped in detail. The essential domains of both promoters lacked canonical eukaryotic core promoter motifs. However, the largest contiguous essential domain in both promoters flanked and included the splice leader addition site. These findings suggested that the region flanking the trans-splicing addition site might represent a conserved core domain in B. malayi promoters. To test this hypothesis, the putative promoters of 12 trans-spliced genes encoding ribosomal protein homologues from B. malayi were isolated and tested for activity in a B. malayi transient transfection system. Of the 12 domains examined, 11 produced detectable reporter gene activity. Mutant constructs of the six most active promoters were prepared in which the spliced leader acceptor site and the10 nt upstream and downstream of the site were deleted. All deletion constructs exhibited >90% reduction in reporter gene activity relative to their respective wild type sequences. A conserved pyrimidine-rich tract was located directly upstream from the spliced leader splice acceptor site which contained a conserved T residue located at position ?3. Mutation of the entire polypyrimidine tract or the conserved T individually resulted in the loss of over 90% of reporter gene activity. In contrast, mutation of the splice acceptor site did not significantly reduce promoter activity. These data suggest that the region surrounding the splice acceptor site in the ribosomal promoters represents a conserved essential domain which functions independently of splice leader addition.

Liu, Canhui; Chauhan, Chitra; Katholi, Charles R.; Unnasch, Thomas R.

2009-01-01

180

The Tumor Suppressor Gene, RASSF1A, Is Essential for Protection against Inflammation -Induced Injury  

PubMed Central

Ras association domain family protein 1A (RASSF1A) is a tumor suppressor gene silenced in cancer. Here we report that RASSF1A is a novel regulator of intestinal inflammation as Rassf1a+/?, Rassf1a?/? and an intestinal epithelial cell specific knockout mouse (Rassf1a IEC-KO) rapidly became sick following dextran sulphate sodium (DSS) administration, a chemical inducer of colitis. Rassf1a knockout mice displayed clinical symptoms of inflammatory bowel disease including: increased intestinal permeability, enhanced cytokine/chemokine production, elevated nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF?B) activity, elevated colonic cell death and epithelial cell injury. Furthermore, epithelial restitution/repair was inhibited in DSS-treated Rassf1a?/? mice with reduction of several makers of proliferation including Yes associated protein (YAP)-driven proliferation. Surprisingly, tyrosine phosphorylation of YAP was detected which coincided with increased nuclear p73 association, Bax-driven epithelial cell death and p53 accumulation resulting in enhanced apoptosis and poor survival of DSS-treated Rassf1a knockout mice. We can inhibit these events and promote the survival of DSS-treated Rassf1a knockout mice with intraperitoneal injection of the c-Abl and c-Abl related protein tyrosine kinase inhibitor, imatinib/gleevec. However, p53 accumulation was not inhibited by imatinib/gleevec in the Rassf1a?/? background which revealed the importance of p53-dependent cell death during intestinal inflammation. These observations suggest that tyrosine phosphorylation of YAP (to drive p73 association and up-regulation of pro-apoptotic genes such as Bax) and accumulation of p53 are consequences of inflammation-induced injury in DSS-treated Rassf1a?/? mice. Mechanistically, we can detect robust associations of RASSF1A with membrane proximal Toll-like receptor (TLR) components to suggest that RASSF1A may function to interfere and restrict TLR-driven activation of NF?B. Failure to restrict NF?B resulted in the inflammation-induced DNA damage driven tyrosine phosphorylation of YAP, subsequent p53 accumulation and loss of intestinal epithelial homeostasis.

Fiteih, Yahya; Law, Jennifer; Volodko, Natalia; Mohamed, Anwar; El-Kadi, Ayman O. S.; Liu, Lei; Odenbach, Jeff; Thiesen, Aducio; Onyskiw, Christina; Ghazaleh, Haya Abu; Park, Jikyoung; Lee, Sean Bong; Yu, Victor C.; Fernandez-Patron, Carlos; Alexander, R. Todd; Wine, Eytan; Baksh, Shairaz

2013-01-01

181

The Am-tra2 Gene Is an Essential Regulator of Female Splice Regulation at Two Levels of the Sex Determination Hierarchy of the Honeybee  

PubMed Central

Heteroallelic and homo- or hemiallelic Complementary sex determiner (Csd) proteins determine sexual fate in the honeybee (Apis mellifera) by controlling the alternative splicing of the downstream gene fem (feminizer). Thus far, we have little understanding of how heteroallelic Csd proteins mediate the splicing of female fem messenger RNAs (mRNAs) or how Fem proteins direct the splicing of honeybee dsx (Am-dsx) pre-mRNAs. Here, we report that Am-tra2, which is an ortholog of Drosophila melanogaster tra2, is an essential component of female splicing of the fem and Am-dsx transcripts in the honeybee. The Am-tra2 transcripts are alternatively (but non-sex-specifically) spliced, and they are translated into six protein isoforms that all share the basic RNA-binding domain/RS (arginine/serine) domain structure. Knockdown studies showed that the Am-tra2 gene is required to splice fem mRNAs into the productive female and nonproductive male forms. We suggest that the Am-Tra2 proteins are essential regulators of fem pre-mRNA splicing that, together with heteroallelic Csd proteins and/or Fem proteins, implement the female pathway. In males, the Am-Tra2 proteins may enhance the switch of fem transcripts into the nonproductive male form when heteroallelic Csd proteins are absent. This dual function of Am-Tra2 proteins possibly enhances and stabilizes the binary decision process of male/female splicing. Our knockdown studies also imply that the Am-Tra2 protein is an essential regulator for Am-dsx female splice regulation, suggesting an ancestral role in holometabolous insects. We also provide evidence that the Am-tra2 gene has an essential function in honeybee embryogenesis that is unrelated to sex determination.

Nissen, Inga; Muller, Miriam; Beye, Martin

2012-01-01

182

Phyto-products may be essential for sustainability and implementation of phytoremediation.  

PubMed

Interest in selenium pollution and remediation technology has escalated during the past two decades. Although not known to be essential for plants, selenium is essential but could be toxic for humans and animals, depending on its concentration. A major selenium controversy in the 1980's emerged in California when the general public and scientific community became aware of selenium's potential as an environmental contaminant. After extensive research on several strategies to reduce loads of mobile Se for entering the agricultural ecosystem a plant-based technology, defined as 'phytoremediation' received increasing recognition, as a low-cost environmentally friendly approach for managing soluble Se in the soil and water environment. Successful long-term field remediation of Se by plants is, however, dependent upon acceptance and widespread use by growers, who are also concerned about potential commercial value from using the plant-based technology. Obtaining products with economic value from plants used in the cleanup of soil would certainly be an additional benefit to phytoremediation, which could help sustain its long-term use. PMID:16519976

Bañuelos, G S

2006-11-01

183

Ultrafine particle emissions from essential-oil-based mosquito repellent products.  

PubMed

Ultrafine particle (UFP) emissions from three essential-oil-based mosquito repellent products (lemon eucalyptus (LE), natural insects (NI), and bite shield (BS)) were tested in a 386 l chamber at a high air exchange rate of 24/h with filtered laboratory air. Total particle number concentration and size distribution were monitored by a condensation particle counter and a scanning mobility particle sizer, respectively. UFPs were emitted from all three products under indoor relevant ozone concentrations (~ 17 ppb). LE showed a nucleation burst followed by a relatively stable and continuous emission while the other two products (NI and BS) showed episodic emissions. The estimated maximum particle emission rate varied from 5.4 × 10(9) to 1.2 × 10(12) particles/min and was directly related to the dose of mosquito repellent used. These rates are comparable to those due to other indoor activities such as cooking and printing. The emission duration for LE lasted for 8-78 min depending on the dose applied while the emission duration for NI and BS lasted for 2-3 h. PMID:24245647

Liu, J; Fung, D; Jiang, J; Zhu, Y

2014-06-01

184

Survivin is essential for fertile egg production and female fertility in mice  

PubMed Central

Survivin is the smallest member of the inhibitor of apoptosis protein (IAP) family and acts as a bifunctional protein involved in mitosis regulation and apoptosis inhibition. To identify the physiological role of Survivin in female reproduction, we selectively disrupted Survivin expression in oocytes and granulosa cells (GCs), two major cell types in the ovary, by two different Cre-Loxp conditional knockout systems, and found that both led to defective female fertility. Survivin deletion in oocytes did not affect oocyte growth, viability and ovulation, but caused tetraploid egg production and thus female infertility. Further exploration revealed that Survivin was essential for regulating proper meiotic spindle organization, spindle assembly checkpoint activity, timely metaphase-to-anaphase transition and cytokinesis. Mutant mice with Survivin depleted in GCs showed reduced ovulation and subfertility, caused by defective follicular growth, increased follicular atresia and impaired luteinization. These findings suggest that Survivin has an important role in regulating folliculogenesis and oogenesis in the adult mouse ovary.

Jiang, Z-Z; Hu, M-W; Wang, Z-B; Huang, L; Lin, F; Qi, S-T; Ouyang, Y-C; Fan, H-Y; Schatten, H; Mak, T W; Sun, Q-Y

2014-01-01

185

Survivin is essential for fertile egg production and female fertility in mice.  

PubMed

Survivin is the smallest member of the inhibitor of apoptosis protein (IAP) family and acts as a bifunctional protein involved in mitosis regulation and apoptosis inhibition. To identify the physiological role of Survivin in female reproduction, we selectively disrupted Survivin expression in oocytes and granulosa cells (GCs), two major cell types in the ovary, by two different Cre-Loxp conditional knockout systems, and found that both led to defective female fertility. Survivin deletion in oocytes did not affect oocyte growth, viability and ovulation, but caused tetraploid egg production and thus female infertility. Further exploration revealed that Survivin was essential for regulating proper meiotic spindle organization, spindle assembly checkpoint activity, timely metaphase-to-anaphase transition and cytokinesis. Mutant mice with Survivin depleted in GCs showed reduced ovulation and subfertility, caused by defective follicular growth, increased follicular atresia and impaired luteinization. These findings suggest that Survivin has an important role in regulating folliculogenesis and oogenesis in the adult mouse ovary. PMID:24675472

Jiang, Z-Z; Hu, M-W; Wang, Z-B; Huang, L; Lin, F; Qi, S-T; Ouyang, Y-C; Fan, H-Y; Schatten, H; Mak, T W; Sun, Q-Y

2014-01-01

186

Production and pathogenicity of hepatitis C virus core gene products  

PubMed Central

Hepatitis C virus (HCV) is a major cause of chronic liver diseases, including steatosis, cirrhosis and hepatocellular carcinoma, and its infection is also associated with insulin resistance and type 2 diabetes mellitus. HCV, belonging to the Flaviviridae family, is a small enveloped virus whose positive-stranded RNA genome encoding a polyprotein. The HCV core protein is cleaved first at residue 191 by the host signal peptidase and further cleaved by the host signal peptide peptidase at about residue 177 to generate the mature core protein (a.a. 1-177) and the cleaved peptide (a.a. 178-191). Core protein could induce insulin resistance, steatosis and even hepatocellular carcinoma through various mechanisms. The peptide (a.a. 178-191) may play a role in the immune response. The polymorphism of this peptide is associated with the cellular lipid drop accumulation, contributing to steatosis development. In addition to the conventional open reading frame (ORF), in the +1 frame, an ORF overlaps with the core protein-coding sequence and encodes the alternative reading frame proteins (ARFP or core+1). ARFP/core+1/F protein could enhance hepatocyte growth and may regulate iron metabolism. In this review, we briefly summarized the current knowledge regarding the production of different core gene products and their roles in viral pathogenesis.

Li, Hui-Chun; Ma, Hsin-Chieh; Yang, Chee-Hing; Lo, Shih-Yen

2014-01-01

187

Genetic evidence that small maf proteins are essential for the activation of antioxidant response element-dependent genes.  

PubMed

While small Maf proteins have been suggested to be essential for the Nrf2-mediated activation of antioxidant response element (ARE)-dependent genes, the extent of their requirement remains to be fully documented. To address this issue, we generated mafG::mafF double-mutant mice possessing MafK as the single available small Maf. Induction of the NAD(P)H:quinone oxidoreductase 1 (NQO1) gene was significantly impaired in double-mutant mice treated with butylated hydroxyanisole, while other ARE-dependent genes were less affected. Similarly, in a keap1-null background, where many of the ARE-dependent genes are constitutively activated in an Nrf2-dependent manner, only a subset of ARE-dependent genes, including NQO1, were sensitive to a simultaneous deficiency in MafG and MafF. Examination of single and double small maf mutant cells revealed that MafK also contributes to the induction of ARE-dependent genes. To obtain decisive evidence, we established mafG::mafK::mafF triple-mutant fibroblasts that completely lack small Mafs and turned out to be highly susceptible to oxidative stress. We found that induction in response to diethyl maleate was abolished in a wider range of ARE-dependent genes in the triple-mutant cells. These data explicitly demonstrate that small Mafs play critical roles in the inducible expression of a significant portion of ARE-dependent genes. PMID:16135796

Katsuoka, Fumiki; Motohashi, Hozumi; Ishii, Tetsuro; Aburatani, Hiroyuki; Engel, James Douglas; Yamamoto, Masayuki

2005-09-01

188

Generation of a Complete Single-Gene Knockout Bacterial Artificial Chromosome Library of Cowpox Virus and Identification of Its Essential Genes  

PubMed Central

Cowpox virus (CPXV) belongs to the genus Orthopoxvirus in the Poxviridae family. It infects a broad range of vertebrates and can cause zoonotic infections. CPXV has the largest genome among the orthopoxviruses and is therefore considered to have the most complete set of genes of all members of the genus. Since CPXV has also become a model for studying poxvirus genetics and pathogenesis, we created and characterized a complete set of single gene knockout bacterial artificial chromosome (BAC) clones of the CPXV strain Brighton Red. These mutants allow a systematic assessment of the contribution of single CPXV genes to the outcome of virus infection and replication, as well as to the virus host range. A full-length BAC clone of CPXV strain Brighton Red (pBRF) harboring the gene expressing the enhanced green fluorescent protein under the control of a viral late promoter was modified by introducing the mrfp1 gene encoding the monomeric red fluorescent protein driven by a synthetic early vaccinia virus promoter. Based on the modified BAC (pBRFseR), a library of targeted knockout mutants for each single viral open reading frame (ORF) was generated. Reconstitution of infectious virus was successful for 109 of the 183 mutant BAC clones, indicating that the deleted genes are not essential for virus replication. In contrast, 74 ORFs were identified as essential because no virus progeny was obtained upon transfection of the mutant BAC clones and in the presence of a helper virus. More than 70% of all late CPXV genes belonged to this latter group of essential genes.

Xu, Zhiyong; Zikos, Dimitrios; Osterrieder, Nikolaus

2014-01-01

189

Combining Hierarchical and Associative Gene Ontology Relations with Textual Evidence in Estimating Gene and Gene Product Similarity  

SciTech Connect

Gene and gene product similarity is a fundamental diagnostic measure in analyzing biological data and constructing predictive models for functional genomics. With the rising influence of the Gene Ontology, two complementary approaches have emerged where the similarity between two genes or gene products is obtained by comparing Gene Ontology (GO) annotations associated with the genes or gene products. One approach captures GO-based similarity in terms of hierarchical relations within each gene subontology. The other approach identifies GO-based similarity in terms of associative relations across the three gene subontologies. We propose a novel methodology where the two approaches can be merged with ensuing benefits in coverage and accuracy, and demonstrate that further improvements can be obtained by integrating textual evidence extracted from relevant biomedical literature.

Sanfilippo, Antonio P.; Posse, Christian; Gopalan, Banu; Riensche, Roderick M.; Beagley, Nathaniel; Baddeley, Bob L.; Tratz, Stephen C.; Gregory, Michelle L.

2007-03-01

190

Gene Regulatory Networks Controlling Hematopoietic Progenitor Niche Cell Production and Differentiation in the Drosophila Lymph Gland  

PubMed Central

Hematopoiesis occurs in two phases in Drosophila, with the first completed during embryogenesis and the second accomplished during larval development. The lymph gland serves as the venue for the final hematopoietic program, with this larval tissue well-studied as to its cellular organization and genetic regulation. While the medullary zone contains stem-like hematopoietic progenitors, the posterior signaling center (PSC) functions as a niche microenvironment essential for controlling the decision between progenitor maintenance versus cellular differentiation. In this report, we utilize a PSC-specific GAL4 driver and UAS-gene RNAi strains, to selectively knockdown individual gene functions in PSC cells. We assessed the effect of abrogating the function of 820 genes as to their requirement for niche cell production and differentiation. 100 genes were shown to be essential for normal niche development, with various loci placed into sub-groups based on the functions of their encoded protein products and known genetic interactions. For members of three of these groups, we characterized loss- and gain-of-function phenotypes. Gene function knockdown of members of the BAP chromatin-remodeling complex resulted in niche cells that do not express the hedgehog (hh) gene and fail to differentiate filopodia believed important for Hh signaling from the niche to progenitors. Abrogating gene function of various members of the insulin-like growth factor and TOR signaling pathways resulted in anomalous PSC cell production, leading to a defective niche organization. Further analysis of the Pten, TSC1, and TSC2 tumor suppressor genes demonstrated their loss-of-function condition resulted in severely altered blood cell homeostasis, including the abundant production of lamellocytes, specialized hemocytes involved in innate immune responses. Together, this cell-specific RNAi knockdown survey and mutant phenotype analyses identified multiple genes and their regulatory networks required for the normal organization and function of the hematopoietic progenitor niche within the lymph gland.

Shoue, Douglas A.; Schulz, Robert A.

2012-01-01

191

A suppressor of two essential checkpoint genes identifies a novel protein that negatively affects dNTP pools.  

PubMed

In Saccharomyces cerevisiae, MEC1 and RAD53 are essential for cell growth and checkpoint function. Their essential role in growth can be bypassed by deletion of a novel gene, SML1, which functions after several genes whose overexpression also suppresses mec1 inviability. In addition, sml1 affects various cellular processes analogous to overproducing the large subunit of ribonucleotide reductase, RNR1. These include effects on mitochondrial biogenesis, on the DNA damage response, and on cell growth. Consistent with these observations, the levels of dNTP pools in sml1 delta strains are increased compared to wild-type. This effect is not due to an increase in RNR transcription. Finally, both in vivo and in vitro experiments show that Sml1 binds to Rnr1. We propose that Sml1 inhibits dNTP synthesis posttranslationally by binding directly to Rnr1 and that Mec1 and Rad53 are required to relieve this inhibition. PMID:9774971

Zhao, X; Muller, E G; Rothstein, R

1998-09-01

192

Aromatic plants essential oils activity on Fusarium verticillioides Fumonisin B(1) production in corn grain.  

PubMed

The minimum inhibitory concentration (MIC) of Origanum vulgare, Aloysia triphylla, Aloysia polystachya and Mentha piperita essential oils (EOs) against Fusarium verticillioides M 7075 (F. moniliforme, Sheldon) were assessed, using the semisolid agar antifungal susceptibility (SAAS) technique. O. vulgare, A. triphylla, A. polystachya and M. piperita EOs were evaluated at final concentrations of 10, 20, 40, 50, 100, 200, 250, 500, 1000 and 1500 epsilonl per litre (epsilonl/l) of culture medium. A. triphylla and O. vulgare EOs showed the highest inhibitory effects on F. verticillioides mycelial development. This inhibition was observed at 250 and 500 epsilonl/l for EOs coming from Aloysia triphylla and O. vulgare, respectively. Thus, the effects of EOs on FB(1) production were evaluated using corn grain (Zea mays) as substrate. The EOs were inserted on the 5th, 10th, 15th and 20th day of maize postinoculation with a conidia suspension of F. verticillioides. O. vulgare and A. triphylla were applied to give final concentrations of 30 ppm and 45 ppm, respectively. Different effects were observed in the toxicogenicity at the 20th day treatment. The O. vulgare EO decreased the production level of FB(1) (P < 0.01) while A. triphyla EO increased it (P < 0.001) with respect to those obtained in the inoculated maize, not EOs treated. Results obtained in the present work indicate that fumonisin production could be inhibited or stimulated by some constituents of EOs coming from aromatic plants. Further studies should be performed to identify the components of EOs with modulatory activity on the growth and fumonisins production of Fusarium verticillioides. PMID:15702272

López, A G; Theumer, M G; Zygadlo, J A; Rubinstein, H R

2004-10-01

193

Variant in the sequence of the LINGO1 gene confers risk of essential tremor  

PubMed Central

We identified a marker in LINGO1 showing genome-wide significant association (P = 1.2 × 10?9, odds ratio = 1.55) with essential tremor. LINGO1 has potent, negative regulatory influences on neuronal survival and is also important in regulating both central-nervous-system axon regeneration and oligodendrocyte maturation. An increase in the number of fusiform swellings of Purkinje cell axons in LINGO1 knockout models highlights the potential role of LINGO1 in essential tremor pathophysiology.

Stefansson, Hreinn; Steinberg, Stacy; Petursson, Hjorvar; Gustafsson, Omar; Gudjonsdottir, Iris H; Jonsdottir, Gudrun A; Palsson, Stefan T; Jonsson, Thorlakur; Saemundsdottir, Jona; Bjornsdottir, Gyda; Bottcher, Yvonne; Thorlacius, Theodora; Haubenberger, Dietrich; Zimprich, Alexander; Auff, Eduard; Hotzy, Christoph; Testa, Claudia M; Miyatake, Lisa A; Rosen, Ami R; Kristleifsson, Kristleifur; Rye, David; Asmus, Friedrich; Schols, Ludger; Dichgans, Martin; Jakobsson, Finnbogi; Benedikz, John; Thorsteinsdottir, Unnur; Gulcher, Jeffrey; Kong, Augustine; Stefansson, Kari

2013-01-01

194

The ZIC gene family encodes multi-functional proteins essential for patterning and morphogenesis.  

PubMed

The zinc finger of the cerebellum gene (ZIC) discovered in Drosophila melanogaster (odd-paired) has five homologs in Xenopus, chicken, mice, and humans, and seven in zebrafish. This pattern of gene copy expansion is accompanied by a divergence in gene and protein structure, suggesting that Zic family members share some, but not all, functions. ZIC genes are implicated in neuroectodermal development and neural crest cell induction. All share conserved regions encoding zinc finger domains, however their heterogeneity and specification remain unexplained. In this review, the evolution, structure, and expression patterns of the ZIC homologs are described; specific functions attributable to individual family members are supported. A review of data from functional studies in Xenopus and murine models suggest that ZIC genes encode multifunctional proteins operating in a context-specific manner to drive critical events during embryogenesis. The identification of ZIC mutations in congenital syndromes highlights the relevance of these genes in human development. PMID:23443491

Houtmeyers, Rob; Souopgui, Jacob; Tejpar, Sabine; Arkell, Ruth

2013-10-01

195

Combinatorial regulation of genes essential for Myxococcus xanthus development involves a response regulator and a LysR-type regulator  

PubMed Central

Myxococcus xanthus is a bacterium that undergoes multicellular development. C-signaling influences gene expression and movement of cells into aggregates. Expression of the dev operon, which includes genes essential for efficient sporulation, depends in part on C-signaling and reaches its highest level in cells within aggregates, ensuring that spores form within fruiting bodies. Here, an upstream DNA element was found to be essential for dev promoter activity and was bound by FruA, a response regulator in the C-signaling pathway. A second positive regulatory element, located ?350 bp downstream of the dev transcriptional start site, was bound by LadA, a newly identified transcription factor in the LysR family. Typically, LysR-type transcription factors bind upstream of the promoter and activate transcription in response to a coinducer. LadA appears to activate transcription from an unusual location for a LysR family member and likely subjects dev transcription to a different cue than does FruA. A ladA mutant exhibited similar developmental defects as dev mutants, suggesting that LadA may be devoted to dev regulation, unlike FruA, which regulates many developmental genes. FruA and LadA act on a regulatory region spanning >400 bp to bring about proper temporal and spatial expression of the dev operon, resembling the regulation of developmental genes in multicellular eukaryotes.

Viswanathan, Poorna; Ueki, Toshiyuki; Inouye, Sumiko; Kroos, Lee

2007-01-01

196

laminin alpha 1 gene is essential for normal lens development in zebrafish  

Microsoft Academic Search

BACKGROUND: Laminins represent major components of basement membranes and play various roles in embryonic and adult tissues. The functional laminin molecule consists of three chains, alpha, beta and gamma, encoded by separate genes. There are twelve different laminin genes identified in mammals to date that are highly homologous in their sequence but different in their tissue distribution. The laminin alpha

Natalya S Zinkevich; Dmitry V Bosenko; Brian A Link; Elena V Semina

2006-01-01

197

Identification of essential genes in cultured mammalian cells using small interfering RNAs  

Microsoft Academic Search

characterized by other methods such as knockout of murine genes are included as internal controls and gave identical results when RNAi was used. In the case of two nonessential genes (lamin A\\/C and zyxin) RNAi provides a recognizable phenotype. Our results complete the characterization of the mammalian nuclear lamins. While lamins A\\/C appear as nonessential proteins in the mouse embryo

Jens Harborth; Sayda M. Elbashir; Kim Bechert; Thomas Tuschl; Klaus Weber; Cell Biology

2001-01-01

198

Six4, a Putative myogenin Gene Regulator, Is Not Essential for Mouse Embryonal Development  

Microsoft Academic Search

Six4 is a member of the Six family genes, homologues of Drosophila melanogaster sine oculis. The gene is thought to be involved in neurogenesis, myogenesis, and development of other organs, based on its specific expression in certain neuronal cells of the developing embryo and in adult skeletal muscles. To elucidate the biological roles of Six4, we generated Six4-deficient mice by

HIDENORI OZAKI; YOKO WATANABE; KATSUMASA TAKAHASHI; KEN KITAMURA; AKIRA TANAKA; KOKO URASE; TAKASHI MOMOI; KATSUKO SUDO; JUNKO SAKAGAMI; MASAHIDE ASANO; YOICHIRO IWAKURA; KIYOSHI KAWAKAMI

2001-01-01

199

From technology to biology: a malaria genetic toolbox for the functional dissection of essential genes.  

PubMed

Possessing a system that experimentally controls gene expression has been a Holy Grail in molecular malaria research. Several strategies to control gene expression at different levels have been developed; the controlled step can range from transcription initiation to post-translational modification and/or protein degradation. Strategies successfully developed in model organisms and adapted to the malaria parasite can be classified into four categories aimed at the conditional control of (i) gene deletion, (ii) gene transcription, (iii) mRNA translation, and (iv) protein stability. Here, I intend to describe the various strategies available and compare and contrast their advantages and limitations. In the absence of a unique, ubiquitous solution, it is instrumental to utilize a variety of approaches that can respond to the particular needs of each gene. PMID:23614838

Pino, Paco

2013-05-01

200

COMPARISON OF THE METHYL REDUCTASE GENES AND GENE PRODUCTS  

EPA Science Inventory

The DNA sequences encoding component C of methyl coenzyme M reductase (mcr genes) in Methanothermus fervidus, Methanobacterium thermoautotrophicum, Methanococcus vannielii, and Methanosarcina barkeri have been published. omparisons of transcription initiation and termination site...

201

Mammalian polycomb-mediated repression of Hox genes requires the essential spliceosomal protein Sf3b1.  

PubMed

Polycomb group (PcG) proteins are responsible for the stable repression of homeotic (Hox) genes by forming multimeric protein complexes. We show (1) physical interaction between components of the U2 small nuclear ribonucleoprotein particle (U2 snRNP), including Sf3b1 and PcG proteins Zfp144 and Rnf2; and (2) that Sf3b1 heterozygous mice exhibit skeletal transformations concomitant with ectopic Hox expressions. These alterations are enhanced by Zfp144 mutation but repressed by Mll mutation (a trithorax-group gene). Importantly, the levels of Sf3b1 in PcG complexes were decreased in Sf3b1-heterozygous embryos. These findings suggest that Sf3b1-PcG protein interaction is essential for true PcG-mediated repression of Hox genes. PMID:15741318

Isono, Kyoichi; Mizutani-Koseki, Yoko; Komori, Toshihisa; Schmidt-Zachmann, Marion S; Koseki, Haruhiko

2005-03-01

202

Spatially explicit measures of production of young alewives in Lake Michigan: Linkage between essential fish habitat and recruitment  

Microsoft Academic Search

The identification and protection of essential habitats for early life stages of fishes are necessary to sustain fish stocks.\\u000a Essential fish habitat for early life stages may be defined as areas where fish densities, growth, survival, or production\\u000a rates are relatively high. To identify critical habitats for young-of-year (YOY) alewives (Alosa pseud oharengus) in Lake Michigan, we integrated bioenergetics models

Tomas O. Höök; Edward S. Rutherford; Shannon J. Brines; Doran M. Mason; David J. Schwab; Michael J. McCormick; Timothy J. DeSorcie

2003-01-01

203

Isolation of a cDNA encoding the human homolog of COX17, a yeast gene essential for mitochondrial copper recruitment.  

PubMed

The COX17 gene of Saccharomyces cerevisiae codes for a cytoplasmic protein essential for the expression of functional cytochrome oxidase. This protein has been implicated in targeting copper to mitochondria. To determine if Cox17p is present in mammalian cells, a yeast strain carrying a null mutation in COX17 was transformed with a human cDNA expression library. All the respiratory competent clones obtained from the transformations carried a common cDNA sequence with a reading frame predicting a product homologous to yeast Cox17p. The cloning of a mammalian COX17 homolog suggests that the encoded product is likely to function in copper recruitment in eucaryotic cells in general. Its presence in humans provides a possible target for genetically inherited deficiencies in cytochrome oxidase. PMID:9050918

Amaravadi, R; Glerum, D M; Tzagoloff, A

1997-03-01

204

Regulation of dev, an Operon That Includes Genes Essential for Myxococcus xanthus Development and CRISPR-Associated Genes and Repeats?  

PubMed Central

Expression of dev genes is important for triggering spore differentiation inside Myxococcus xanthus fruiting bodies. DNA sequence analysis suggested that dev and cas (CRISPR-associated) genes are cotranscribed at the dev locus, which is adjacent to CRISPR (clustered regularly interspaced short palindromic repeats). Analysis of RNA from developing M. xanthus confirmed that dev and cas genes are cotranscribed with a short upstream gene and at least two repeats of the downstream CRISPR, forming the dev operon. The operon is subject to strong, negative autoregulation during development by DevS. The dev promoter was identified. Its ?35 and ?10 regions resemble those recognized by M. xanthus ?A RNA polymerase, the homolog of Escherichia coli ?70, but the spacer may be too long (20 bp); there is very little expression during growth. Induction during development relies on at least two positive regulatory elements located in the coding region of the next gene upstream. At least two positive regulatory elements and one negative element lie downstream of the dev promoter, such that the region controlling dev expression spans more than 1 kb. The results of testing different fragments for dev promoter activity in wild-type and devS mutant backgrounds strongly suggest that upstream and downstream regulatory elements interact functionally. Strikingly, the 37-bp sequence between the two CRISPR repeats that, minimally, are cotranscribed with dev and cas genes exactly matches a sequence in the bacteriophage Mx8 intP gene, which encodes a form of the integrase needed for lysogenization of M. xanthus.

Viswanathan, Poorna; Murphy, Kimberly; Julien, Bryan; Garza, Anthony G.; Kroos, Lee

2007-01-01

205

Effect of Citrus reticulata and Cymbopogon citratus essential oils on Aspergillus flavus growth and aflatoxin production on Asparagus racemosus.  

PubMed

Essential oils extracted from Citrus reticulata and Cymbopogon citratus were tested in vitro against the toxigenic strain of Aspergillus flavus, isolated from the tuberous roots of Asparagus racemosus, used in preparation of herbal drugs. The essential oils completely inhibited the growth of A. flavus at 750 ppm and also exhibited a broad fungitoxic spectrum against nine additional fungi isolated from the roots. Citrus reticulata and Cymbopogon citratus essential oils completely inhibited aflatoxin B(1) production at 750 and 500 ppm, respectively. During in vivo investigation, the incidence of fungi and aflatoxin B(1) production decreased considerably in essential oil-treated root samples. The findings thus indicate possible exploitation of the essential oils as effective inhibitor of aflatoxin B(1) production and as post-harvest fungitoxicant of traditionally used plant origin for the control of storage fungi. These essential oils may be recommended as plant-based antifungals as well as aflatoxin B(1) suppressors in post-harvest processing of herbal samples. PMID:20401550

Singh, Priyanka; Shukla, Ravindra; Kumar, Ashok; Prakash, Bhanu; Singh, Shubhra; Dubey, Nawal Kishore

2010-09-01

206

The lineage-specific gene ponzr1 is essential for zebrafish pronephric and pharyngeal arch development.  

PubMed

The Homeobox (Hox) and Paired box (Pax) gene families are key determinants of animal body plans and organ structure. In particular, they function within regulatory networks that control organogenesis. How these conserved genes elicit differences in organ form and function in response to evolutionary pressures is incompletely understood. We molecularly and functionally characterized one member of an evolutionarily dynamic gene family, plac8 onzin related protein 1 (ponzr1), in the zebrafish. ponzr1 mRNA is expressed early in the developing kidney and pharyngeal arches. Using ponzr1-targeting morpholinos, we show that ponzr1 is required for formation of the glomerulus. Loss of ponzr1 results in a nonfunctional glomerulus but retention of a functional pronephros, an arrangement similar to the aglomerular kidneys found in a subset of marine fish. ponzr1 is integrated into the pax2a pathway, with ponzr1 expression requiring pax2a gene function, and proper pax2a expression requiring normal ponzr1 expression. In addition to pronephric function, ponzr1 is required for pharyngeal arch formation. We functionally demonstrate that ponzr1 can act as a transcription factor or co-factor, providing the first molecular mode of action for this newly described gene family. Together, this work provides experimental evidence of an additional mechanism that incorporates evolutionarily dynamic, lineage-specific gene families into conserved regulatory gene networks to create functional organ diversity. PMID:22274699

Bedell, Victoria M; Person, Anthony D; Larson, Jon D; McLoon, Anna; Balciunas, Darius; Clark, Karl J; Neff, Kevin I; Nelson, Katie E; Bill, Brent R; Schimmenti, Lisa A; Beiraghi, Soraya; Ekker, Stephen C

2012-02-01

207

The lonD gene is homologous to the lon gene encoding an ATP-dependent protease and is essential for the development of Myxococcus xanthus.  

PubMed Central

Myxococcus xanthus contains two genes (lonV and lonD) homologous to the Escherichia coli lon gene for an ATP-dependent protease. We found that the lonD gene encodes a 90-kDa protein consisting of 827 amino acid residues. The lonD gene product shows 49, 48, and 52% sequence identity to the products of the M. xanthus lonV, E. coli lon, and Bacillus brevis lon genes, respectively. When a lonD-lacZ fusion was used, lonD was expressed during both vegetative growth and development. However, while lonD-disrupted strains were able to grow normally vegetatively, the development of M. xanthus was found to be arrested at an early stage in these strains. The mutant strains were able to form neither fruiting bodies nor myxospores.

Tojo, N; Inouye, S; Komano, T

1993-01-01

208

The Role of the Parkinson's Disease Gene PARK9 in Essential Cellular Pathways and the Manganese Homeostasis Network in Yeast  

PubMed Central

YPK9 (Yeast PARK9; also known as YOR291W) is a non-essential yeast gene predicted by sequence to encode a transmembrane P-type transport ATPase. However, its substrate specificity is unknown. Mutations in the human homolog of YPK9, ATP13A2/PARK9, have been linked to genetic forms of early onset parkinsonism. We previously described a strong genetic interaction between Ypk9 and another Parkinson's disease (PD) protein ?-synuclein in multiple model systems, and a role for Ypk9 in manganese detoxification in yeast. In humans, environmental exposure to toxic levels of manganese causes a syndrome similar to PD and is thus an environmental risk factor for the disease. How manganese contributes to neurodegeneration is poorly understood. Here we describe multiple genome-wide screens in yeast aimed at defining the cellular function of Ypk9 and the mechanisms by which it protects cells from manganese toxicity. In physiological conditions, we found that Ypk9 genetically interacts with essential genes involved in cellular trafficking and the cell cycle. Deletion of Ypk9 sensitizes yeast cells to exposure to excess manganese. Using a library of non-essential gene deletions, we screened for additional genes involved in tolerance to excess manganese exposure, discovering several novel pathways involved in manganese homeostasis. We defined the dependence of the deletion strain phenotypes in the presence of manganese on Ypk9, and found that Ypk9 deletion modifies the manganese tolerance of only a subset of strains. These results confirm a role for Ypk9 in manganese homeostasis and illuminates cellular pathways and biological processes in which Ypk9 likely functions.

Chesi, Alessandra; Kilaru, Austin; Fang, Xiaodong; Cooper, Antony A.; Gitler, Aaron D.

2012-01-01

209

Correlating Information Contents of Gene Ontology Terms to Infer Semantic Similarity of Gene Products  

PubMed Central

Successful applications of the gene ontology to the inference of functional relationships between gene products in recent years have raised the need for computational methods to automatically calculate semantic similarity between gene products based on semantic similarity of gene ontology terms. Nevertheless, existing methods, though having been widely used in a variety of applications, may significantly overestimate semantic similarity between genes that are actually not functionally related, thereby yielding misleading results in applications. To overcome this limitation, we propose to represent a gene product as a vector that is composed of information contents of gene ontology terms annotated for the gene product, and we suggest calculating similarity between two gene products as the relatedness of their corresponding vectors using three measures: Pearson's correlation coefficient, cosine similarity, and the Jaccard index. We focus on the biological process domain of the gene ontology and annotations of yeast proteins to study the effectiveness of the proposed measures. Results show that semantic similarity scores calculated using the proposed measures are more consistent with known biological knowledge than those derived using a list of existing methods, suggesting the effectiveness of our method in characterizing functional relationships between gene products.

2014-01-01

210

Integrating Ontological Knowledge and Textual Evidence in Estimating Gene and Gene Product Similarity  

SciTech Connect

With the rising influence of the Gene On-tology, new approaches have emerged where the similarity between genes or gene products is obtained by comparing Gene Ontology code annotations associ-ated with them. So far, these approaches have solely relied on the knowledge en-coded in the Gene Ontology and the gene annotations associated with the Gene On-tology database. The goal of this paper is to demonstrate that improvements to these approaches can be obtained by integrating textual evidence extracted from relevant biomedical literature.

Sanfilippo, Antonio P.; Posse, Christian; Gopalan, Banu; Tratz, Stephen C.; Gregory, Michelle L.

2006-06-08

211

trp, a Novel Mammalian Gene Family Essential for Agonist-Activated Capacitative Ca 2+ Entry  

Microsoft Academic Search

Capacitative calcium entry (CCE) describes Ca2+ influx into cells that replenishes Ca2+ stores emptied through the action of IP3 and other agents. It is an essential component of cellular responses to many hormones and growth factors. The molecular basis of this form of Ca2+ entry is complex and may involve more than one type of channel. Studies on visual signal

Xi Zhu; Meisheng Jiang; Michael Peyton; Guylain Boulay; Raymond Hurst; Enrico Stefani; Lutz Birnbaumer

1996-01-01

212

Cytotoxicity and gene induction by some essential oils in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

In order to get an insight into the possible genotoxicity of essential oils (EOs) used in traditional pharmacological applications we tested five different oils extracted from the medicinal plants Origanum compactum, Coriandrum sativum, Artemisia herba alba, Cinnamomum camphora (Ravintsara aromatica) and Helichrysum italicum (Calendula officinalis) for genotoxic effects using the yeast Saccharomyces cerevisiae. Clear cytotoxic effects were observed in the

F. Bakkali; S. Averbeck; D. Averbeck; A. Zhiri; M. Idaomar

2005-01-01

213

ACE2 gene polymorphism and essential hypertension: an updated meta-analysis involving 11,051 subjects.  

PubMed

The polymorphisms of angiotensin-converting enzyme 2 (ACE2) gene have been suggested to be linked to increase risk of essential hypertension in multiple populations. However, the results are still debatable. To assess the association between ACE2 G8970A genetic polymorphism and essential hypertension, we conducted a meta-analysis of case-control studies across different ethnicity. PubMed, Embase, CBM, Wanfang and VIP databases were searched, and a total of 11 separate studies in females and nine separate studies in males met the inclusion criteria. Because ACE2 is on the X chromosome, data for each sex were analyzed separately. The selected studies contained 7,251 (4,472 females/2,779 males) hypertensive patients and 3,800 (2,161 females/1,639 males) normotensive controls. A statistically significant association was observed between the G8970A gene polymorphism and essential hypertension risk in female hypertensive group in the recessive genetic model (AA vs. GG+GA: P = 0.03, OR = 1.15, 95% CI = 1.02-1.30, P(heterogeneity) = 0.40, I(2) = 5%, fixed-effects model). Although no association was shown between the frequency of the A allele and the genetic susceptibility to essential hypertension in all male patients (A Allele: P = 0.38, OR = 1.10, 95% CI = 0.89-1.38, P(heterogeneity) = 0.02, I(2) = 56%, random-effects model), we found that the relationship between carrier of A allele and the essential hypertension risk in Han-Chinese male patients subgroup (A Allele: P = 0.006, OR = 1.21, 95% CI = 1.06–1.38, P(heterogeneity) = 0.10, I(2) = 44%, fixed-effects model). The current meta-analysis provided solid evidence suggesting that ACE2 gene polymorphism G8790A was probably a genetic risk factor for essential hypertension across different ethnic populations in female subjects and in Han-Chinese male subjects. PMID:22297693

Lu, Na; Yang, Yang; Wang, Yibo; Liu, Yan; Fu, Gang; Chen, Dongmei; Dai, Hui; Fan, Xiaohan; Hui, Rutai; Zheng, Yang

2012-06-01

214

Formulating essential oil microemulsions as washing solutions for organic fresh produce production.  

PubMed

Applications of plant-derived organic essential oils (EOs) as antimicrobials for post-harvest produce operations are limited by their low water solubility. To dissolve EOs in water, microemulsions were studied using two surfactants permitted for organic production, sucrose octanoate ester (SOE) and soy lecithin that were mixed at various mass ratios before dilution with water to 40% w/w. EOs were then mixed with the surfactant solution by hand shaking. Based on visual transparency, intermediate lecithin:SOE mass ratios favoured the formation of microemulsions, e.g., up to 4.0% clove bud oil at ratios of 2:8 and 3:7, and 4.0% cinnamon bark oil and 3.0% thyme oil at ratios of 2:8 and 1:9, respectively. Microemulsions with intermediate lecithin:SOE mass ratios had a relatively low viscosity and better ability to wet fresh produce surfaces. The microemulsions established in this work may be used as washing solutions to enhance the microbial safety of organic fresh produce. PMID:25038656

Zhang, Linhan; Critzer, Faith; Davidson, P Michael; Zhong, Qixin

2014-12-15

215

L-plastin is essential for alveolar macrophage production and control of pulmonary pneumococcal infection.  

PubMed

We report that mice deficient for the hematopoietic-specific, actin-bundling protein L-plastin (LPL) succumb rapidly to intratracheal pneumococcal infection. The increased susceptibility of LPL(-/-) mice to pulmonary pneumococcal challenge correlated with reduced numbers of alveolar macrophages, consistent with a critical role for this cell type in the immediate response to pneumococcal infection. LPL(-/-) mice demonstrated a very early clearance defect, with an almost 10-fold-higher bacterial burden in the bronchoalveolar lavage fluid 3 h following infection. Clearance of pneumococci from the alveolar space in LPL(-/-) mice was defective compared to that in Rag1(-/-) mice, which lack all B and T lymphocytes, indicating that innate immunity is defective in LPL(-/-) mice. We did not identify defects in neutrophil or monocyte recruitment or in the production of inflammatory cytokines or chemokines that would explain the early clearance defect. However, efficient alveolar macrophage regeneration following irradiation required LPL. We thus identify LPL as being key to alveolar macrophage development and essential to an effective antipneumococcal response. Further analysis of LPL(-/-) mice will illuminate critical regulators of the generation of alveolar macrophages and, thus, effective pulmonary innate immunity. PMID:24595139

Deady, Lauren E; Todd, Elizabeth M; Davis, Chris G; Zhou, Julie Y; Topcagic, Nermina; Edelson, Brian T; Ferkol, Thomas W; Cooper, Megan A; Muenzer, Jared T; Morley, Sharon Celeste

2014-05-01

216

The trans-activator gene of HTLV-III is essential for virus replication  

Microsoft Academic Search

Studies of the genomic structure of human T-lymphotropic virus type III (HTLV-III) and related viruses, implicated as the causal agent of acquired immune deficiency syndrome (AIDS), have identified a sixth open reading frame in addition to the five previously known within the genome (gag, pol, sor, env and 3'orf)1-4. This gene, called tat-III, lies between the sorand env genes and

Amanda G. Fisher; Mark B. Feinberg; Steven F. Josephs; Mary E. Harper; Lisa M. Marselle; Gregory Reyes; Matthew A. Gonda; Anna Aldovini; Christine Debouk; Robert C. Gallo; Flossie Wong-Staal

1986-01-01

217

MicroRNA regulation of human protease genes essential for influenza virus replication.  

PubMed

Influenza A virus causes seasonal epidemics and periodic pandemics threatening the health of millions of people each year. Vaccination is an effective strategy for reducing morbidity and mortality, and in the absence of drug resistance, the efficacy of chemoprophylaxis is comparable to that of vaccines. However, the rapid emergence of drug resistance has emphasized the need for new drug targets. Knowledge of the host cell components required for influenza replication has been an area targeted for disease intervention. In this study, the human protease genes required for influenza virus replication were determined and validated using RNA interference approaches. The genes validated as critical for influenza virus replication were ADAMTS7, CPE, DPP3, MST1, and PRSS12, and pathway analysis showed these genes were in global host cell pathways governing inflammation (NF-?B), cAMP/calcium signaling (CRE/CREB), and apoptosis. Analyses of host microRNAs predicted to govern expression of these genes showed that eight miRNAs regulated gene expression during virus replication. These findings identify unique host genes and microRNAs important for influenza replication providing potential new targets for disease intervention strategies. PMID:22606348

Meliopoulos, Victoria A; Andersen, Lauren E; Brooks, Paula; Yan, Xiuzhen; Bakre, Abhijeet; Coleman, J Keegan; Tompkins, S Mark; Tripp, Ralph A

2012-01-01

218

MicroRNA Regulation of Human Protease Genes Essential for Influenza Virus Replication  

PubMed Central

Influenza A virus causes seasonal epidemics and periodic pandemics threatening the health of millions of people each year. Vaccination is an effective strategy for reducing morbidity and mortality, and in the absence of drug resistance, the efficacy of chemoprophylaxis is comparable to that of vaccines. However, the rapid emergence of drug resistance has emphasized the need for new drug targets. Knowledge of the host cell components required for influenza replication has been an area targeted for disease intervention. In this study, the human protease genes required for influenza virus replication were determined and validated using RNA interference approaches. The genes validated as critical for influenza virus replication were ADAMTS7, CPE, DPP3, MST1, and PRSS12, and pathway analysis showed these genes were in global host cell pathways governing inflammation (NF-?B), cAMP/calcium signaling (CRE/CREB), and apoptosis. Analyses of host microRNAs predicted to govern expression of these genes showed that eight miRNAs regulated gene expression during virus replication. These findings identify unique host genes and microRNAs important for influenza replication providing potential new targets for disease intervention strategies.

Meliopoulos, Victoria A.; Andersen, Lauren E.; Brooks, Paula; Yan, Xiuzhen; Bakre, Abhijeet; Coleman, J. Keegan; Tompkins, S. Mark; Tripp, Ralph A.

2012-01-01

219

A mutation in the Xanthomonas oryzae pv. oryzae wxoD gene affects xanthan production and chemotaxis.  

PubMed

Xanthomonas oryzae pv. oryzae causes bacterial blight in rice (Oryza sativa L.). The effect of a mutation in the wxoD gene, that encodes a putative O-antigen acetylase, on xanthan production as well as bacterial chemotaxis was investigated. The mutation increased xanthan production by 52 %. The mutant strain was non-motile on semi-solid agar swarm plates. In addition, several genes involved in chemotaxis, including the cheW, cheV, cheR, and cheD genes, were down-regulated by a mutation in the wxoD gene. Thus, the mutation in the wxoD gene affects xanthan production as well as bacterial chemotaxis. However, the wxoD gene is not essential for the virulence of X. oryzae. PMID:23881323

Nam, Jae-Young; Kim, Hong-Il; Lee, Chang-Soo; Park, Young-Jin

2013-11-01

220

Polymorphisms of the Flavin containing monooxygenase 3 (FMO3) gene do not predispose to essential hypertension in Caucasians  

PubMed Central

Background The recessive disorder trimethylaminuria is caused by defects in the FMO3 gene, and may be associated with hypertension. We investigated whether common polymorphisms of the FMO3 gene confer an increased risk for elevated blood pressure and/or essential hypertension. Methods FMO3 genotypes (E158K, V257M, E308G) were determined in 387 healthy subjects with ambulatory systolic and diastolic blood pressure measurements, and in a cardiovascular disease population of 1649 individuals, 691(41.9%) of whom had a history of hypertension requiring drug treatment. Haplotypes were determined and their distribution noted. Results There was no statistically significant association found between any of the 4 common haplotypes and daytime systolic blood pressure in the healthy population (p = 0.65). Neither was a statistically significant association found between the 4 common haplotypes and hypertension status among the cardiovascular disease patients (p = 0.80). Conclusion These results suggest that the variants in the FMO3 gene do not predispose to essential hypertension in this population.

Dolan, Ciara; Shields, Denis C; Stanton, Alice; O'Brien, Eoin; Lambert, Deborah M; O'Brien, John K; Treacy, Eileen P

2005-01-01

221

Recombinase-based reporter system and antisense technology to study gene expression and essentiality in hypoxic nonreplicating mycobacteria.  

PubMed

The study of the mechanisms used by Mycobacterium tuberculosis to survive in the absence of growth is hampered by the absence of appropriate genetic tools. Here, we report two strategies, a recombinase-based reporter system and an antisense technology, to study gene expression and essentiality in hypoxic nonreplicating mycobacteria. The recombinase-based reporter system relies on the resolution of an antibiotic marker flanked by the gammadelta-res sites. This system was developed to identify M. tuberculosis promoters, which are specifically expressed under anaerobic conditions. The antisense strategy was designed to study the role of a gene candidate during anaerobic survival. To validate this approach, the dosR, narK2 and rv2466c promoters were selected to drive dosR antisense mRNA expression in quiescent mycobacteria. The conditional knockout strains were found to be attenuated to adapt and survive under anaerobic conditions, as observed for the dosR knockout strain. Together, our work demonstrates that the recombinase-based reporter system and antisense technology represent two genetic tools useful for the identification and characterization of genes essential for the survival of hypoxic nonreplicating M. tuberculosis. PMID:18544099

Rao, Srinivasa P S; Camacho, Luis; Huat Tan, Bee; Boon, Calvin; Russel, David G; Dick, Thomas; Pethe, Kevin

2008-07-01

222

A cytochrome c biogenesis gene involved in pyoverdine production in Pseudomonas fluorescens ATCC 17400.  

PubMed

Pseudomonas fluorescens ATCC 17400 produces pyoverdine under iron-limiting conditions. A Tn5 mutant, 2G11, produced lower amounts of different pyoverdine forms and was unable to grow under iron limitation caused by ethylenediamine-di(o-hydroxy-phenylacetic acid) (EDDHA) or zinc. This mutant was complemented by a 9.6 kb HindIII-BamHI DNA fragment that contained eight contiguous open reading frames (ORFs cytA to cytH). The proteins possibly encoded by this polycistronic gene cluster were all similar to the products of cytochrome c biogenesis genes from, amongst others, Rhodobacter capsulatus and Bradyrhizobium japonicum, not only in terms of amino acid sequence, but also in the overall hydropathy index of these proteins. By TnphoA mutagenesis and site-specific gene replacement it was found that the first three ORFs (cytA to cytC) were essential for cytochrome c production while only the product of cytA was needed for normal pyoverdine production. The presence of a putative haem-binding site in the CytA protein (WGSWWVWD) was confirmed. From analysis of a constructed phoA fusion, a periplasmic location was found for this motif. The ability of the cytA gene to restore both cytochrome c and pyoverdine production suggests the involvement of this particular gene both in haem and in pyoverdine transport in P. fluorescens. PMID:8878040

Gaballa, A; Koedam, N; Cornelis, P

1996-08-01

223

Conditional silencing of topoisomerase I gene of Mycobacterium tuberculosis validates its essentiality for cell survival.  

PubMed

Topoisomerases are an important class of enzymes for regulating the DNA transaction processes. Mycobacterium tuberculosis (Mtb) is one of the most formidable pathogens also posing serious challenges for therapeutic interventions. The organism contains only one type IA topoisomerase (Rv3646c), offering an opportunity to test its potential as a candidate drug target. To validate the essentiality of M. tuberculosis topoisomerase I (TopoI(Mt) ) for bacterial growth and survival, we have generated a conditionally regulated strain of topoI in Mtb. The conditional knockdown mutant exhibited delayed growth on agar plate. In liquid culture, the growth was drastically impaired when TopoI expression was suppressed. Additionally, novobiocin and isoniazid showed enhanced inhibitory potential against the conditional mutant. Analysis of the nucleoid revealed its altered architecture upon TopoI depletion. These studies establish the essentiality of TopoI for the M. tuberculosis growth and open up new avenues for targeting the enzyme. PMID:24593153

Ahmed, Wareed; Menon, Shruti; Godbole, Adwait Anand; Karthik, Pullela V D N B; Nagaraja, Valakunja

2014-04-01

224

The transcription factor MTF-1 is essential for basal and heavy metal-induced metallothionein gene expression.  

PubMed Central

We have described and cloned previously a factor (MTF-1) that binds specifically to heavy metal-responsive DNA sequence elements in the enhancer/promoter region of metallothionein genes. MTF-1 is a protein of 72.5 kDa that contains six zinc fingers and multiple domains for transcriptional activation. Here we report the disruption of both alleles of the MTF-1 gene in mouse embryonic stem cells by homologous recombination. The resulting null mutant cell line fails to produce detectable amounts of MTF-1. Moreover, due to the loss of MTF-1, the endogenous metallothionein I and II genes are silent, indicating that MTF-1 is required for both their basal and zinc-induced transcription. In addition to zinc, other heavy metals, including cadmium, copper, nickel and lead, also fail to activate metal-responsive promoters in null mutant cells. However, cotransfection of an MTF-1 expression vector and metal-responsive reporter genes yields strong basal transcription that can be further boosted by zinc treatment of cells. These results demonstrate that MTF-1 is essential for metallothionein gene regulation. Finally, we present evidence that MTF-1 itself is a zinc sensor, which exhibits increased DNA binding activity upon zinc treatment. Images

Heuchel, R; Radtke, F; Georgiev, O; Stark, G; Aguet, M; Schaffner, W

1994-01-01

225

Human PTCHD3 nulls: rare copy number and sequence variants suggest a non-essential gene  

Microsoft Academic Search

Background  Copy number variations (CNVs) can contribute to variable degrees of fitness and\\/or disease predisposition. Recent studies\\u000a show that at least 1% of any given genome is copy number variable when compared to the human reference sequence assembly.\\u000a Homozygous deletions (or CNV nulls) that are found in the normal population are of particular interest because they may serve\\u000a to define non-essential

Mohammad M Ghahramani Seno; Benjamin YM Kwan; Ka Ki M Lee-Ng; Rainald Moessner; Anath C Lionel; Christian R Marshall; Stephen W Scherer

2011-01-01

226

Precisely positioned nucleosomes are not essential for c-fos gene regulation in vivo.  

PubMed

Chromatin architecture plays a decisive role in many aspects of transcription regulation. We have tested the role of specific chromatin structures in c-fos gene regulation, using a gene transfer system based on episomes derived from the Epstein-Barr virus (EBV). This system reproduces in several respects the chromatin structure and regulation of the chromosomal c-fos gene. Using this approach, we first demonstrate that the pausing of RNA polymerase II downstream of the transcriptional start site does not require precisely positioned nucleosomes. Indeed, changing the pattern of MNase hypersensitive sites along the transcribed sequence does not perturb RNA polymerase II pausing or the regulation of the c-fos gene. Next, we show that a putative nucleosome positioned between the SIE/SRE elements (-300) and the CRE/TATA elements (-36) is not necessary for activation by a variety of inducers. Accordingly, total or partial deletion of the putative nucleosome sequence does not disturb c-fos regulation while the two regulatory sites flanking the nucleosome sequence remain hypersensitive to MNase. As described in this paper, EBV episomes are useful vectors to critically examine the role of the chromatin structure in gene transcription for human cells. PMID:11024277

Fivaz, J; Bassi, M C; Price, M; Pinaud, S; Mirkovitch, J

2000-09-19

227

Impact of oregano essential oil on production data and lipid oxidation parameters in broiler chickens  

Microsoft Academic Search

In a study with male broiler chickens the impact of dietary oregano essential oil on performance data and on the susceptibility of abdominal fat, fresh and stored breast muscle tissue to lipid oxidation was examined. Four diets supplemented either with oregano essential oil in two levels (22.5 mg (OL) and 90 (OH) mg kg-1 feed ), 40 mg ?-tocopheryl acetate

R. Messikommer; S. Baltzer; C. Wenk

228

Reconstituting pancreas development from purified progenitor cells reveals genes essential for islet differentiation  

PubMed Central

Developmental biology is challenged to reveal the function of numerous candidate genes implicated by recent genome-scale studies as regulators of organ development and diseases. Recapitulating organogenesis from purified progenitor cells that can be genetically manipulated would provide powerful opportunities to dissect such gene functions. Here we describe systems for reconstructing pancreas development, including islet ?-cell and ?-cell differentiation, from single fetal progenitor cells. A strict requirement for native genetic regulators of in vivo pancreas development, such as Ngn3, Arx, and Pax4, revealed the authenticity of differentiation programs in vitro. Efficient genetic screens permitted by this system revealed that Prdm16 is required for pancreatic islet development in vivo. Discovering the function of genes regulating pancreas development with our system should enrich strategies for regenerating islets for treating diabetes mellitus.

Sugiyama, Takuya; Benitez, Cecil M.; Ghodasara, Amar; Liu, Lucy; McLean, Graeme W.; Lee, Jonghyeob; Blauwkamp, Timothy A.; Nusse, Roeland; Wright, Christopher V. E.; Gu, Guoqiang; Kim, Seung K.

2013-01-01

229

Reconstituting pancreas development from purified progenitor cells reveals genes essential for islet differentiation.  

PubMed

Developmental biology is challenged to reveal the function of numerous candidate genes implicated by recent genome-scale studies as regulators of organ development and diseases. Recapitulating organogenesis from purified progenitor cells that can be genetically manipulated would provide powerful opportunities to dissect such gene functions. Here we describe systems for reconstructing pancreas development, including islet ?-cell and ?-cell differentiation, from single fetal progenitor cells. A strict requirement for native genetic regulators of in vivo pancreas development, such as Ngn3, Arx, and Pax4, revealed the authenticity of differentiation programs in vitro. Efficient genetic screens permitted by this system revealed that Prdm16 is required for pancreatic islet development in vivo. Discovering the function of genes regulating pancreas development with our system should enrich strategies for regenerating islets for treating diabetes mellitus. PMID:23852729

Sugiyama, Takuya; Benitez, Cecil M; Ghodasara, Amar; Liu, Lucy; McLean, Graeme W; Lee, Jonghyeob; Blauwkamp, Timothy A; Nusse, Roeland; Wright, Christopher V E; Gu, Guoqiang; Kim, Seung K

2013-07-30

230

Fratricide Is Essential for Efficient Gene Transfer between Pneumococci in Biofilms  

PubMed Central

Streptococcus pneumoniae and a number of commensal streptococcal species are competent for natural genetic transformation. The natural habitat of these bacteria is multispecies biofilms in the human oral cavity and nasopharynx. Studies investigating lateral transfer of virulence and antibiotic resistance determinants among streptococci have shown that interspecies as well as intraspecies gene exchange takes place in these environments. We have previously shown that the action of a competence-specific murein hydrolase termed CbpD strongly increases the rate of gene transfer between pneumococci grown in liquid cultures. CbpD is the key component of a bacteriolytic mechanism termed the fratricide mechanism. It is secreted by competent pneumococci and mediates the release of donor DNA from sensitive streptococci present in the same environment. However, in nature, gene exchange between streptococci takes place in biofilms and not in liquid cultures. In the present study, we therefore investigated whether CbpD affects the rate of gene transfer in laboratory-grown biofilms. Our results show that the fratricide mechanism has a strong positive impact on intrabiofilm gene exchange, indicating that it is important for active acquisition of homologous donor DNA under natural conditions. Furthermore, we found that competent biofilm cells of S. pneumoniae acquire a Novr marker much more efficiently from neighboring cells than from the growth medium. Efficient lysis of target cells requires that CbpD act in conjunction with the murein hydrolase LytC. In contrast, the major autolysin LytA does not seem to be important for fratricide-mediated gene exchange in a biofilm environment.

Wei, Hua

2012-01-01

231

Foxa3 (HNF-3gamma) binds to and activates the rat proglucagon gene promoter but is not essential for proglucagon gene expression.  

PubMed Central

Members of the Forkhead box a (Foxa) transcription factor family are expressed in the liver, pancreatic islets and intestine and both Foxa1 and Foxa2 regulate proglucagon gene transcription. As Foxa proteins exhibit overlapping DNA-binding specificities, we examined the role of Foxa3 [hepatocyte nuclear factor (HNF)-3gamma] in control of proglucagon gene expression. Foxa3 was detected by reverse transcriptase PCR in glucagon-producing cell lines and binds to the rat proglucagon gene G2 promoter element in GLUTag enteroendocrine cells. Although Foxa3 increased rat proglucagon promoter activity in BHK fibroblasts, augmentation of Foxa3 expression did not increase proglucagon promoter activity in GLUTag cells. Furthermore, adenoviral Foxa3 expression did not affect endogenous proglucagon gene expression in islet or intestinal endocrine cell lines. Although Foxa3(-/-) mice exhibit mild hypoglycaemia during a prolonged fast, the levels of proglucagon-derived peptides and proglucagon mRNA transcripts were comparable in tissues from wild-type and Foxa3(-/-) mice. These findings identify Foxa3 as a member of the proglucagon gene G2 element binding-protein family that, unlike Foxa1, is not essential for control of islet or intestinal proglucagon gene expression in vivo.

Liu, Yuanfang; Shen, Wei; Brubaker, Patricia L; Kaestner, Klaus H; Drucker, Daniel J

2002-01-01

232

Heterologous production of fosfomycin and identification of the minimal biosynthetic gene cluster.  

PubMed

Fosfomycin is a clinically utilized, highly effective antibiotic, which is active against methicillin- and vancomycin-resistant pathogens. Here we report the cloning and characterization of a complete fosfomycin biosynthetic cluster from Streptomyces fradiae and heterologous production of fosfomycin in S. lividans. Sequence analysis coupled with gene deletion and disruption revealed that the minimal cluster consists of fom1-4, fomA-D. A LuxR-type activator that was apparently required for heterologous fosfomycin production was also discovered approximately 13 kb away from the cluster and was named fomR. The genes fomE and fomF, previously thought to be involved in fosfomycin biosynthesis, were shown not to be essential by gene disruption. This work provides new insights into fosfomycin biosynthesis and opens the door for fosfomycin overproduction and creation of new analogs via biomolecular pathway engineering. PMID:17113999

Woodyer, Ryan D; Shao, Zengyi; Thomas, Paul M; Kelleher, Neil L; Blodgett, Joshua A V; Metcalf, William W; van der Donk, Wilfred A; Zhao, Huimin

2006-11-01

233

The discoidin domain of Bacillus circulans ?-galactosidase plays an essential role in repressing galactooligosaccharide production.  

PubMed

The recently cloned ?-galactosidase from Bacillus circulans ATCC 31382, designated BgaD, contains a multiple domain architecture including a F5/8 type C domain or a discoidin (DS) domain in the C-terminal peptide region. Here we report that the DS domain plays an essential role in repressing the production of galactooligosaccharides (GOSs). We prepared deletion mutants and point-mutated forms of rBgaD-A (deletion of the BgaD signal peptide) to compare their reaction behaviors. The yields of GOSs for all of the point-mutated forms as well as the deletion mutants of rBgaD-As increased as compared to rBgaD-A. In particular, W1540A mutant BgaD-A (rBgaD-A_W1540A) produced much more GOSs than rBgaD-A. Surface plasmon resonance experiments indicated that both the wild-type and the W1540A mutant DS domains showed high affinity for galactosyllactose. rBgaD-A, which has a wild-type DS domain, showed high hydrolytic activity toward galactosyllactose, while the hydrolytic activities of rBgaD-D, without a DS domain, and rBgaD-A_W1540A, with a mutant DS domain were extremely low. The findings obtained in this study indicate that the wild-type DS domain of rBgaD-A has a function that aids galactosyllactose molecules to be properly oriented within the active site, so that they can be hydrolyzed efficiently to produce galactose/glucose by inhibiting the accumulation of GOSs. PMID:23291776

Song, Jingyuan; Imanaka, Hiroyuki; Imamura, Koreyoshi; Minoda, Masashi; Yamaguchi, Shotaro; Nakanishi, Kazuhiro

2013-01-01

234

Essential Roles for Mycobacterium tuberculosis Rel beyond the Production of (p)ppGpp  

PubMed Central

In Mycobacterium tuberculosis, the stringent response to amino acid starvation is mediated by the M. tuberculosis Rel (RelMtb) enzyme, which transfers a pyrophosphate from ATP to GDP or GTP to synthesize ppGpp and pppGpp, respectively. (p)ppGpp then influences numerous metabolic processes. RelMtb also encodes a second, distinct catalytic domain that hydrolyzes (p)ppGpp into pyrophosphate and GDP or GTP. RelMtb is required for chronic M. tuberculosis infection in mice; however, it is unknown which catalytic activity of RelMtb mediates pathogenesis and whether (p)ppGpp itself is necessary. In order to individually investigate the roles of (p)ppGpp synthesis and hydrolysis during M. tuberculosis pathogenesis, we generated RelMtb point mutants that were either synthetase dead (RelMtbH344Y) or hydrolase dead (RelMtbH80A). M. tuberculosis strains expressing the synthetase-dead RelMtbH344Y mutant did not persist in mice, demonstrating that the RelMtb (p)ppGpp synthetase activity is required for maintaining bacterial titers during chronic infection. Deletion of a second predicted (p)ppGpp synthetase had no effect on pathogenesis, demonstrating that RelMtb was the major contributor to (p)ppGpp production during infection. Interestingly, expression of an allele encoding the hydrolase-dead RelMtb mutant, RelMtbH80A, that is incapable of hydrolyzing (p)ppGpp but still able to synthesize (p)ppGpp decreased the growth rate of M. tuberculosis and changed the colony morphology of the bacteria. In addition, RelMtbH80A expression during acute or chronic M. tuberculosis infection in mice was lethal to the infecting bacteria. These findings highlight a distinct role for RelMtb-mediated (p)ppGpp hydrolysis that is essential for M. tuberculosis pathogenesis.

Weiss, Leslie A.

2013-01-01

235

Essential roles for Mycobacterium tuberculosis Rel beyond the production of (p)ppGpp.  

PubMed

In Mycobacterium tuberculosis, the stringent response to amino acid starvation is mediated by the M. tuberculosis Rel (RelMtb) enzyme, which transfers a pyrophosphate from ATP to GDP or GTP to synthesize ppGpp and pppGpp, respectively. (p)ppGpp then influences numerous metabolic processes. RelMtb also encodes a second, distinct catalytic domain that hydrolyzes (p)ppGpp into pyrophosphate and GDP or GTP. RelMtb is required for chronic M. tuberculosis infection in mice; however, it is unknown which catalytic activity of RelMtb mediates pathogenesis and whether (p)ppGpp itself is necessary. In order to individually investigate the roles of (p)ppGpp synthesis and hydrolysis during M. tuberculosis pathogenesis, we generated RelMtb point mutants that were either synthetase dead (RelMtb(H344Y)) or hydrolase dead (RelMtb(H80A)). M. tuberculosis strains expressing the synthetase-dead RelMtb(H344Y) mutant did not persist in mice, demonstrating that the RelMtb (p)ppGpp synthetase activity is required for maintaining bacterial titers during chronic infection. Deletion of a second predicted (p)ppGpp synthetase had no effect on pathogenesis, demonstrating that RelMtb was the major contributor to (p)ppGpp production during infection. Interestingly, expression of an allele encoding the hydrolase-dead RelMtb mutant, RelMtb(H80A), that is incapable of hydrolyzing (p)ppGpp but still able to synthesize (p)ppGpp decreased the growth rate of M. tuberculosis and changed the colony morphology of the bacteria. In addition, RelMtb(H80A) expression during acute or chronic M. tuberculosis infection in mice was lethal to the infecting bacteria. These findings highlight a distinct role for RelMtb-mediated (p)ppGpp hydrolysis that is essential for M. tuberculosis pathogenesis. PMID:24123821

Weiss, Leslie A; Stallings, Christina L

2013-12-01

236

Isolation of a herpes simplex virus type 1 mutant deleted for the essential UL42 gene and characterization of its null phenotype.  

PubMed Central

We isolated a cell line, designated V9, stably transformed with the herpes simplex virus type 1 (HSV-1) UL42 gene, which is one of seven genes required in trans for the replication of plasmids containing an HSV origin of replication (C. A. Wu, N. J. Nelson, D. J. McGeoch, and M. D. Challberg, J. Virol. 62:435-443, 1988). V9 cells inducibly expressed the product of the UL42 gene, the 65-kDa DNA-binding protein (65KDBP), and were used as a permissive host to construct a mutant virus deleted for this essential gene. The UL42 deletion mutant, designated Cgal delta 42, displayed a tight early phenotype in nonpermissive Vero cells producing no infectious progeny, viral DNA, or late gene products but accumulated selected immediate-early and early transcripts with kinetics similar to those of wild-type virus. Wild-type levels of viral DNA and infectious progeny were produced in permissive V9 cells, despite the fact that V9 cells infected with Cgal delta 42 accumulated less than 1% of the UL42 RNA and protein found in Cgal+ virus-infected V9 or Vero cells. These results indicate that only small quantities of the 65KDBP are required for the synthesis of HSV DNA and the production of infectious virus. Although we could find no evidence that the superinduction of the 65KDBP in V9 cells infected with Cgal+ repressed expression of HSV-1 genes as observed in cells expressing another DNA-binding protein, ICP8 (P. K. Orberg and P. A. Schaffer, J. Virol. 61:1136-1146, 1987), the induction of the 65KDBP in V9 cells correlated with an approximately 2-h-earlier shift in the expression of genes from all three kinetic classes. The availability of the UL42 mutant should facilitate the construction of more subtle UL42 mutants which will be useful in the elucidation of the interrelationship between the 65KDBP and other DNA replication proteins as well as in the characterization of additional important functional domains. Images

Johnson, P A; Best, M G; Friedmann, T; Parris, D S

1991-01-01

237

The homeobox gene Hhex is essential for proper hepatoblast differentiation and bile duct morphogenesis  

Microsoft Academic Search

Hhex is required for early development of the liver. A null mutation of Hhex results in a failure to form the liver bud and embryonic lethality. Therefore, Hhex null mice are not informative as to whether this gene is required during later stages of hepatobiliary morphogenesis. To address this question, we derived Hhex conditional null mice using the Cre-loxP system

Michael P. Hunter; Christine M. Wilson; Xiaobing Jiang; Rong Cong; Hemaxi Vasavada; Klaus H. Kaestner; Clifford W. Bogue

2007-01-01

238

Math1: An Essential Gene for the Generation of Inner Ear Hair Cells  

Microsoft Academic Search

The mammalian inner ear contains the cochlea and vestibular organs, which are responsible for hearing and balance, respectively. The epithelia of these sensory organs contain hair cells that function as mechanoreceptors to transduce sound and head motion. The molecular mechanisms underlying hair cell development and differentiation are poorly understood. Math1, a mouse homolog of the Drosophila proneural gene atonal, is

Nessan A. Bermingham; Bassem A. Hassan; Steven D. Price; Melissa A. Vollrath; Nissim Ben-Arie; Ruth Anne Eatock; Hugo J. Bellen H J; Huda Y. Zoghbi

1999-01-01

239

fusilli, an essential gene with a maternal role in Drosophila embryonic dorsal-ventral patterning.  

PubMed

The Drosophila fusilli (fus) gene was identified in a genetic screen for dominant maternal enhancers of an unusual dorsalizing mutation in the cactus gene, cact(E10). While females that are heterozygous for the cact(E10) allele produce embryos with wild-type dorsal-ventral patterning, more than 90% of the embryos produced by females that are heterozygous for both cact(E10) and the fus(1) mutation are weakly dorsalized. Loss of fusilli activity causes lethality during embryogenesis but not dorsal-ventral patterning defects, indicating that fusilli is important in more than one developmental process. The fusilli gene encodes a protein with RNA binding motifs related to those in mammalian hnRNP F and H, which play roles in regulated RNA splicing. The fusilli RNA is not present in the oocyte or early embryo, and germ-line clones of fusilli mutations have no maternal effect on dorsal-ventral patterning, indicating that the fusilli maternal effect does not depend on germ-line expression of the gene. Because the fusilli RNA is present in ovarian follicle cells, we propose that fusilli acts downstream of the Drosophila EGF receptor to control the biogenesis of follicle cell transcripts that control the initial dorsal-ventral asymmetry of the embryo. PMID:11133153

Wakabayashi-Ito, N; Belvin, M P; Bluestein, D A; Anderson, K V

2001-01-01

240

Systematic screening of type B human natriuretic peptide receptor gene polymorphisms and association with essential hypertension  

Microsoft Academic Search

C-type natriuretic peptide (CNP) dilates arteries, lowers blood pressure and inhibits proliferation of vascular smooth muscle cells via the type B natriuretic peptide receptor (NPRB). The CNP-NPRB system may play a crucial role in the development of cardiovascular disease. We recently determined the structure of the human NPRB gene. In the present study, our objectives are to identify the polymorphisms

D Rahmutula; T Nakayama; M Soma; M Sato; Y Izumi; K Kanmatsuse; Y Ozawa

2001-01-01

241

Identification of genes essential for prey-independent growth of Bdellovibrio bacteriovorus HD100.  

PubMed

Bdellovibrio bacteriovorus HD100 is an obligate predatory bacterium that attacks and invades Gram-negative bacteria. The predator requires living bacteria to survive as growth and replication take place inside the bacterial prey. It is possible to isolate mutants that grow and replicate outside prey bacteria. Such mutants are designated host or prey independent, and their nutritional requirements vary. Some mutants are saprophytic and require prey extracts for extracellular growth, whereas other mutants grow axenically, which denotes the formation of colonies on complete medium in the absence of any prey components. The initial events leading to prey-independent growth are still under debate, and several genes may be involved. We selected new mutants by three different methods: spontaneous mutation, transposon mutagenesis, and targeted gene knockout. By all approaches we isolated mutants of the hit (host interaction) locus. As the relevance of this locus for the development of prey independence has been questioned, we performed whole-genome sequencing of five prey-independent mutants. Three mutants were saprophytic, and two mutants could grow axenically. Whole-genome analysis revealed that the mutation of a small open reading frame of the hit locus is sufficient for the conversion from predatory to saprophytic growth. Complementation experiments were performed by introduction of a plasmid carrying the wild-type hit gene into saprophytic mutants, and predatory growth could be restored. Whole-genome sequencing of two axenic mutants demonstrated that in addition to the hit mutation the colony formation on complete medium was shown to be influenced by the mutations of two genes involved in RNA processing. Complementation experiments with a wild-type gene encoding an RNA helicase, RhlB, abolished the ability to form colonies on complete medium, indicating that stability of RNA influences axenic growth. PMID:21278289

Roschanski, Nicole; Klages, Sven; Reinhardt, Richard; Linscheid, Michael; Strauch, Eckhard

2011-04-01

242

The Hsp60C gene in the 25F cytogenetic region in Drosophila melanogaster is essential for tracheal development and fertility  

Microsoft Academic Search

Earlier studies have shown that of the four genes (Hsp60A, Hsp60B, Hsp60C, Hsp60D genes) predicted to encode the conserved Hsp60 family chaperones inDrosophila melanogaster, theHsp60A gene (at the 10A polytene region) is expressed in all cell types of the organism and is essential from early embryonic stages,\\u000a while theHsp60B gene (at 21D region) is expressed only in testis, being essential

Surajit Sarkar; Subhash C. Lakhotia

2005-01-01

243

Islands of non-essential genes, including a DNA translocation operon, in the genome of bacteriophage 0305?8-36  

PubMed Central

We investigate genes of lytic, Bacillus thuringiensis bacteriophage 0305?8-36 that are non-essential for laboratory propagation, but might have a function in the wild. We isolate deletion mutants to identify these genes. The non-permutation of the genome (218.948 Kb, with a 6.479 Kb terminal repeat and 247 identified orfs) simplifies isolation of deletion mutants. We find two islands of non-essential genes. The first island (3.01% of the genomic DNA) has an informatically identified DNA translocation operon. Deletion causes no detectable growth defect during propagation in a dilute agarose overlay. Identification of the DNA translocation operon begins with a DNA relaxase and continues with a translocase and membrane-binding anchor proteins. The relaxase is in a family, first identified here, with homologs in other bacteriophages. The second deleted island (3.71% of the genome) has genes for two metallo-protein chaperonins and two tRNAs. Deletion causes a significant growth defect. In addition, (1) we find by “in situ” (in-plaque) single-particle fluorescence microscopy that adsorption to the host occurs at the tip of the 486 nm long tail, (2) we develop a procedure of 0305?8-36 purification that does not cause tail contraction, and (3) we then find by electron microscopy that 0305?8-36 undergoes tail tip-tail tip dimerization that potentially blocks adsorption to host cells, presumably with effectiveness that increases as the bacteriophage particle concentration increases. These observations provide an explanation of the previous observation that 0305?8-36 does not lyse liquid cultures, even though 0305?8-36 is genomically lytic.

Pathria, Saurav; Rolando, Mandy; Lieman, Karen; Hayes, Shirley; Hardies, Stephen; Serwer, Philip

2012-01-01

244

Tasks Essential to Successful Performance within Animal Production and Management Occupations in Ohio. Summary of Research Series.  

ERIC Educational Resources Information Center

A study was conducted to identify the skills which are performed and essential for success in seven animal production and management (small animal care) occupations: animal health assistant, laboratory animal assistant, kennel worker, dog groomer, pet shop worker, stable worker, and zoo keeper. Specific objectives were (1) to develop and validate…

Hampson, Michael N.; McCracken, J. David

245

Cross-Ontological Analytics: Combining Associative and Hierarchical Relations in the Gene Ontologies to Assess Gene Product Similarity  

SciTech Connect

Gene and gene product similarity is a fundamental diagnostic measure in analyzing biological data and constructing predictive models for functional genomics. With the rising influence of the gene ontologies, two complementary approaches have emerged where the similarity between two genes/gene products is obtained by comparing gene ontology (GO) annotations associated with the gene/gene products. One approach captures GO-based similarity in terms of hierarchical relations within each gene ontology. The other approach identifies GO-based similarity in terms of associative relations across the three gene ontologies. We propose a novel methodology where the two approaches can be merged with ensuing benefits in coverage and accuracy.

Posse, Christian; Sanfilippo, Antonio P.; Gopalan, Banu; Riensche, Roderick M.; Beagley, Nathaniel; Baddeley, Bob L.

2006-05-28

246

The extended auricle1 (eta1) gene is essential for the genetic network controlling postinitiation maize leaf development.  

PubMed Central

The maize leaf is composed of distinct regions with clear morphological boundaries. The ligule and auricle mark the boundary between distal blade and proximal sheath and are amenable to genetic study due to the array of mutants that affect their formation without severely affecting viability. Herein, we describe the novel maize gene extended auricle1 (eta1), which is essential for proper formation of the blade/sheath boundary. Homozygous eta1 individuals have a wavy overgrowth of auricle tissue and the blade/sheath boundary is diffuse. Double-mutant combinations of eta1 with genes in the knox and liguleless pathways result in synergistic and, in some cases, dosage-dependent interactions. While the phenotype of eta1 mutant individuals resembles that of dominant knox overexpression phenotypes, eta1 mutant leaves do not ectopically express knox genes. In addition, eta1 interacts synergistically with lg1 and lg2, but does not directly affect the transcription of either gene in leaf primordia. We present evidence based on genetic and molecular analyses that eta1 provides a downstream link between the knox and liguleless pathways.

Osmont, Karen S; Jesaitis, Lynne A; Freeling, Michael

2003-01-01

247

The only essential function of TFIIIA in yeast is the transcription of 5S rRNA genes.  

PubMed Central

We have developed a system to transcribe the yeast 5S rRNA gene in the absence of the transcription factor TFIIIA. A long transcript was synthesized both in vitro and in vivo from a hybrid gene in which the tRNA-like promoter sequence of the RPR1 gene was fused to the yeast 5S RNA gene. No internal initiation directed by the endogenous 5S rDNA promoter or any processing of the hybrid transcript was observed in vitro. Yeast cells devoid of transcription factor TFIIIA, which, therefore, could not synthesize any 5S rRNA from the endogenous chromosomal copies of 5S rDNA, could survive if they carried the hybrid RPR1-5S construct on a multicopy plasmid. In this case, the only source of 5S rRNA was the precursor RPR1-5S transcript that gave rise to two RNA species slightly larger than wild-type 5S rRNA. This establishes that the only essential function of TFIIIA is to promote the synthesis of 5S rRNA. However, cells devoid of TFIIIA and surviving with these two RNAs grew more slowly at 30 degrees C compared with wild-type cells and were thermosensitive at 37 degrees C. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

Camier, S; Dechampesme, A M; Sentenac, A

1995-01-01

248

A Conditional Mouse Model for Measuring the Frequency of Homologous Recombination Events In Vivo in the Absence of Essential Genes?‡  

PubMed Central

The ability to detect and repair DNA damage is crucial to the prevention of various diseases. Loss of function of genes involved in these processes is known to result in significant developmental defects and/or predisposition to cancer. One such DNA repair mechanism, homologous recombination, has the capacity to repair a wide variety of lesions. Knockout mouse models of genes thought to be involved in DNA repair processes are frequently lethal, making in vivo studies very difficult, if not impossible. Therefore, we set out to develop an in vivo conditional mouse model system to facilitate investigations into the involvement of essential genes in homologous recombination. To test our model, we measured the frequency of spontaneous homologous recombination using the pink-eyed unstable mouse model, in which we conditionally excised either Blm or full-length Brca1 (breast cancer 1, early onset). These two genes are hypothesized to have opposing roles in homologous recombination. In summary, our in vivo data supports in vitro studies suggesting that BLM suppresses homologous recombination, while full-length BRCA1 promotes this process.

Brown, Adam D.; Claybon, Alison B.; Bishop, Alexander J. R.

2011-01-01

249

Transducin beta-like gene FTL1 is essential for pathogenesis in Fusarium graminearum  

Microsoft Academic Search

Fusarium head blight caused by Fusarium graminearum is an important disease of wheat and barley. In a previous study, we identified several mutants with reduced virulence by insertional mutagenesis. A transducin beta-like gene named FTL1 was disrupted in one of these nonpathogenic mutants. FTL1 is homologous to Saccharomyces cerevisiae SIF2, which is a component of the Set3 complex involved in

Shengli Ding; Rahim Mehrabi; Cornelia Koten; Zhensheng Kang; Yangdou Wei; Kyeyong Seong; H. Corby Kistler; Jin-Rong Xu

2009-01-01

250

Identification of a New Gene Essential for Germination of Bacillus subtilis Spores with Ca2+-Dipicolinate  

Microsoft Academic Search

Ca2-DPA. The other two were mapped to an open reading frame, ywdL, encoding a protein of unknown function. Analysis of ywdL expression showed that the gene is expressed during sporulation in the mother cell compartment of the sporulating cell and that its transcription is E dependent. Functional characterization of YwdL demonstrated that it is a new spore coat protein that

Katerina Ragkousi; Patrick Eichenberger; Christiaan van Ooij; Peter Setlow

2003-01-01

251

Tissue-specific methylation occurs in the essential promoter element of the tyrosine hydroxylase gene  

Microsoft Academic Search

Expression of tyrosine hydroxylase (TH) is regulated in a tissue-specific manner by multiple mechanisms. In catecholaminergic cells, the expression of TH-mRNA is up-regulated by forskolin (FK) and is suppressed by retinoic acid (RA). We have previously provided evidence that, in N-18 cells, the expression of TH-mRNA is suppressed by DNA methylation of the TH gene itself. In the present study,

Kenji Okuse; Ichiro Matsuoka; Kenzo Kurihara

1997-01-01

252

Isolation of the ?-tubulin gene from yeast and demonstration of its essential function in vivo  

Microsoft Academic Search

Summary A DNA fragment from yeast (Saccharomyces cere- visiae) was identified by its homology to a chicken p-tubulin cDNA and cloned. The fragment was shown to be unique in the yeast genome and to contain the gene for yeast fi-tubulin, since it can complement a benomyl-resistant conditional-lethal mutation. A smaller subfragment, when used to di- rect integration of a plasmid

Norma F. Neff; James H. Thomas; Paula Grisafi; David Botstein

1983-01-01

253

Ribosomal biogenesis genes play an essential and p53-independent role in zebrafish pancreas development  

PubMed Central

Mutations in the human Shwachman-Bodian-Diamond syndrome (SBDS) gene cause defective ribosome assembly and are associated with exocrine pancreatic insufficiency, chronic neutropenia and skeletal defects. However, the mechanism underlying these phenotypes remains unclear. Here we show that knockdown of the zebrafish sbds ortholog fully recapitulates the spectrum of developmental abnormalities observed in the human syndrome, and further implicate impaired proliferation of ptf1a-expressing pancreatic progenitor cells as the basis for the observed pancreatic phenotype. It is thought that diseases of ribosome assembly share a p53-dependent mechanism. However, loss of p53 did not rescue the developmental defects associated with loss of zebrafish sbds. To clarify the molecular mechanisms underlying the observed organogenesis defects, we performed transcriptional profiling to identify candidate downstream mediators of the sbds phenotype. Among transcripts displaying differential expression, functional group analysis revealed marked enrichment of genes related to ribosome biogenesis, rRNA processing and translational initiation. Among these, ribosomal protein L3 (rpl3) and pescadillo (pes) were selected for additional analysis. Similar to knockdown of sbds, knockdown or mutation of either rpl3 or pes resulted in impaired expansion of pancreatic progenitor cells. The pancreatic phenotypes observed in rpl3- and pes-deficient embryos were also independent of p53. Together, these data suggest novel p53-independent roles for ribosomal biogenesis genes in zebrafish pancreas development.

Provost, Elayne; Wehner, Karen A.; Zhong, Xiangang; Ashar, Foram; Nguyen, Elizabeth; Green, Rachel; Parsons, Michael J.; Leach, Steven D.

2012-01-01

254

Heterologous production of desferrioxamines with a fusion biosynthetic gene cluster.  

PubMed

Desferrioxamines E (1), D2 (2), X1 (3), and X2 (4), four macrocyclic N-hydroxy-N-succinyl diamine-based siderophores, were produced efficiently by heterologous expression of a fusion biosynthetic gene cluster. This expression system consisted of three genes (mbsA-C) from marine metagenomic DNA and one gene (dfoC(C)) from the terrestrial bacterium Erwinia amylovora. The first three genes are functional in the production of the common monomers N-hydroxy-N-succinyl cadaverine (5, HSC) and N-hydroxy-N-succinyl putrescine (6, HSP), whereas dfoC(C) catalyzes the oligomerization and the macrocyclization reactions of compounds 5 and 6 to form compounds 1-4. This fusion gene cluster system provides a convenient expression platform for various biosynthetic genes of HSC-HSP based siderophores by simply switching the fourth gene by the cassette process. PMID:24317070

Fujita, Masaki J; Sakai, Ryuichi

2013-01-01

255

TIF1-GAMMA PLAYS AN ESSENTIAL ROLE IN MURINE HEMATOPOIESIS AND REGULATES TRANSCRIPTIONAL ELONGATION OF ERYTHROID GENES  

PubMed Central

Transcriptional regulators play critical roles in the regulation of cell fate during hematopoiesis. Previous studies in zebrafish have identified an essential role for the transcriptional intermediary factor TIF1? in erythropoiesis through regulating the transcription elongation of erythroid genes. To study if TIF1? plays a similar role in murine erythropoiesis and to assess its function in other blood lineages, we generated mouse models with hematopoietic deletion of TIF1?. Our results showed a block in erythroid maturation in the bone marrow following tif1? deletion that was compensated with enhanced spleen erythropoiesis. Further analyses revealed a defect in transcription elongation of erythroid genes in the bone marrow. In addition, loss of TIF1? resulted in defects in other blood compartments, including a profound loss of B cells, a dramatic expansion of granulocytes and decreased HSC function. TIF1? exerts its functions in a cell-autonomous manner as revealed by competitive transplantation experiments. Our study therefore demonstrates that TIF1? plays essential roles in multiple murine blood lineages and that its function in transcription elongation is evolutionally conserved.

Bai, Xiaoying; Trowbridge, Jennifer J.; Riley, Elizabeth; Lee, Joseph A.; DiBiase, Anthony; Kaartinen, Vesa M.; Orkin, Stuart H.; Zon, Leonard I.

2012-01-01

256

Post transcriptional regulation of chloroplast gene expression by nuclear encoded gene products  

SciTech Connect

Many individual chloroplast genes require the products of a collection of nuclear genes for their successful expression. These nuclear gene products apparently work with great specificity, each committed to the expression of a single chloroplast gene. We have chosen as a model nuclear mutants of Chlamydomonas affected in different stages in the expression of the chloroplast encoded Photosystem II polypeptide, D2. We have made the progress in understanding how nuclear gene products affect the translation of the D2 encoding MRNA. Two nuclear genes are required for this process which have been mapped genetically. In contrast to other examples of nuclear control of translation in the chloroplast, these nuclear gene products appear to be required either for specific stages in translation elongation or for the post-translational stabilization of the nascent D2 protein. Pseudoreversion analysis has led us to a locus which may be directly involved in D2 expression. We have made considerable progress in pursuing the molecular basis of psbd MRNA stabilization. psbD 5' UTR specific transcripts have been synthesized in vitro and used in gel mobility shift assays. UV-crosslinking studies are underway to identify the transacting factors which bind to these sequences. The continued examination of these mutants will help us to understand how nuclear gene products work in this specific case of chloroplast gene expression, and will elucidate how two distinct genomes can interact generally.

Kuchka, M.R.

1992-01-01

257

Fumigant Toxicity and Oviposition Deterrency of the Essential Oil from Cardamom, Elettaria cardamomum, Against Three Stored--product Insects  

PubMed Central

Use of insecticides can have disruptive effects on the environment. Replacing the chemical compounds in these insecticides with plant materials, however, can be a safe method with low environmental risk. In the current study, chemical composition and insecticidal activities of the essential oil from cardamom, Elettaria cardamomum L. (Maton) (Zingiberales: Zingiberaceae) on the adults of three stored product pests was investigated. Results indicated that essential oil of E. cardamomum toxic to the bruchid beetle, Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae), the red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), and the flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Adults of E. kuehniella were more sensitive than the Coleoptera. Also, the highest mortality of these insects was seen after 12 hours. Results of the LT50 tests showed that the lethal time of mortality occurred between 10–20 hours in various test concentrations. Essential oil of E. cardamomum had a good efficacy on oviposition deterrence of C. maculatus females, too. The chemical constituents of the essential oils were analyzed by gas chromatography—mass spectrometry. The major constituents of cardamom were identified as 1,8-cineol, ?-terpinyl acetate, terpinene and fenchyl alcohol. These results suggest that essential oil of E. cardamomum is a good choice for control of stored product pests.

Abbasipour, Habib; Mahmoudvand, Mohammad; Rastegar, Fahimeh; Hosseinpour, Mohammad Hossein

2011-01-01

258

Fumigant toxicity and oviposition deterrency of the essential oil from cardamom, Elettaria cardamomum, against three stored–product insects.  

PubMed

Use of insecticides can have disruptive effects on the environment. Replacing the chemical compounds in these insecticides with plant materials, however, can be a safe method with low environmental risk. In the current study, chemical composition and insecticidal activities of the essential oil from cardamom, Elettaria cardamomum L. (Maton) (Zingiberales: Zingiberaceae) on the adults of three stored product pests was investigated. Results indicated that essential oil of E. cardamomum toxic to the bruchid beetle, Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae), the red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), and the flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Adults of E. kuehniella were more sensitive than the Coleoptera. Also, the highest mortality of these insects was seen after 12 hours. Results of the LT?? tests showed that the lethal time of mortality occurred between 10-20 hours in various test concentrations. Essential oil of E. cardamomum had a good efficacy on oviposition deterrence of C. maculatus females, too. The chemical constituents of the essential oils were analyzed by gas chromatography-mass spectrometry. The major constituents of cardamom were identified as 1,8-cineol, ?-terpinyl acetate, terpinene and fenchyl alcohol. These results suggest that essential oil of E. cardamomum is a good choice for control of stored product pests. PMID:22242564

Abbasipour, Habib; Mahmoudvand, Mohammad; Rastegar, Fahimeh; Hosseinpour, Mohammad Hossein

2011-01-01

259

Effect of essential oils on Aspergillus spore germination, growth and mycotoxin production: a potential source of botanical food preservative  

PubMed Central

Objective To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production. Method In vitro antifungal and antiaflatoxigenic activity of essential oils was carried out using poisoned food techniques, spore germination assay, agar dilution assay, and aflatoxin arresting assay on toxigenic strains of Aspergillus species. Results Cymbopogon martinii, Foeniculum vulgare and Trachyspermum ammi (T. ammi) essential oils were tested against toxicogenic isolates of Aspergillus species. T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 µl/mL by essential oils of T. ammi. The oil also showed, complete inhibition of spore germination at a concentration of 2 µl/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting aflatoxin production from Aspergillus niger and Aspergillus flavus at 0.5 and 0.75 µl/mL, respectively. Cymbopogon martinii, Foeniculum vulgare and T. ammi oils as antifungal were found superior over synthetic preservative. Moreover, a concentration of 5?336.297 µl/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity and strengthening its traditional reputations. Conclusions In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by storage fungi.

Gemeda, Negero; Woldeamanuel, Yimtubezinash; Asrat, Daniel; Debella, Asfaw

2014-01-01

260

The common NF-?B essential modulator (NEMO) gene rearrangement in Korean patients with incontinentia pigmenti.  

PubMed

Incontinentia pigmenti (IP) is a rare X-linked dominant disorder characterized by highly variable abnormalities of the skin, eyes and central nervous system. A mutation of the nuclear factor-?B essential modulator (NEMO) located at Xq28 is believed to play a role in pathogenesis and the mutation occurs mostly in female patients due to fatal consequence of the mutation in males in utero. This study was designed to identify the common NEMO rearrangement in four Korean patients with IP. Deletion of exons 4 to 10 in the NEMO, the most common mutation in IP patients, was detected in all of the patients by the use of long-range PCR analysis. This method enabled us to discriminate between NEMO and pseudogene rearrangements. Furthermore, all of the patients showed skewed XCI patterns, indicating pathogenicity of IP was due to cells carrying the mutant X chromosome. This is the first report of genetically confirmed cases of IP in Korea. PMID:20890435

Song, Min-Jung; Chae, Jong-Hee; Park, Eun-Ae; Ki, Chang-Seok

2010-10-01

261

Inhibitory effect of the essential oil of Curcuma longa L. and curcumin on aflatoxin production by Aspergillus flavus Link.  

PubMed

Aflatoxins are highly toxic, mutagenic, teratogenic and carcinogenic mycotoxins. Consumption of aflatoxin-contaminated food and commodities poses serious hazards to the health of humans and animals. Turmeric, Curcuma longa L., is a native plant of Southeast Asia and has antimicrobial, antioxidant and antifungal properties. This paper reports the antiaflatoxigenic activities of the essential oil of C. longa and curcumin. The medium tests were prepared with the oil of C. longa, and the curcumin standard at concentrations varied from 0.01% to 5.0%. All doses of the essential oil of the plant and the curcumin standard interfered with mycotoxin production. Both the essential oil and curcumin significantly inhibited the production of aflatoxins; the 0.5% level had a greater than 96% inhibitory effect. The levels of aflatoxin B(1) (AFB(1)) production were 1.0 and 42.7 ?g/mL, respectively, for the samples treated with the essential oil of C. longa L. and curcumin at a concentration of 0.5%. PMID:23122128

Ferreira, Flavio Dias; Kemmelmeier, Carlos; Arrotéia, Carla Cristina; da Costa, Christiane Luciana; Mallmann, Carlos Augusto; Janeiro, Vanderly; Ferreira, Francine Maery Dias; Mossini, Simone Aparecida Galerani; Silva, Expedito Leite; Machinski, Miguel

2013-01-15

262

Campylobacter jejuni gene cj0511 encodes a serine peptidase essential for colonisation  

PubMed Central

According to MEROPS peptidase database, Campylobacter species encode 64 predicted peptidases. However, proteolytic properties of only a few of these proteins have been confirmed experimentally. In this study we identified and characterised a Campylobacter jejuni gene cj0511 encoding a novel peptidase. The proteolytic activity associated with this enzyme was demonstrated in cell lysates. Moreover, enzymatic studies conducted with a purified protein confirmed a prediction of it being a serine peptidase. Furthermore, cj0511 mutant was found to be severely attenuated in chicken colonisation model, suggesting a role of the Cj0511 protein in infection.

Karlyshev, A.V.; Thacker, G.; Jones, M.A.; Clements, M.O.; Wren, B.W.

2014-01-01

263

Association study of common variations of FBN1 gene and essential hypertension in Han Chinese population.  

PubMed

Fibrillin-1 (FBN1) was reported to have impact on the physiological arterial stiffness and vascular remodeling with hypertension of recent years. In the previous study we reported the association of four functional single nucleotide polymorphisms (SNPs) of FBN1 gene and hypertension. Here, we further investigate the association of four tagging SNPs (tagSNPs) which covered remain genetic variation blocks of FBN1 gene with hypertension, blood pressure and efficacy of antihypertensive in a South Han Chinese population. A case-control study including 2,012 hypertension cases and 2,116 controls age- and sex-matched controls was conducted from a community-based population and four candidate tagSNPs of the FBN1 gene were genotyped. Association analysis by multiple logistic regression was conducted for allele, genotype and haplotype and hypertension, blood pressure trait and control status with antihypertensive. General linear model was applied to compare blood pressure levels between genotypes. The association of rs17361868 and hypertension was statistically significant and that was further observed in female, ?55 years, non-smoking and non-drinking populations (P < 0.05). Significant association of rs668842, rs11635140 and hypertension were observed in <55 years population as well as the later in female and non-smoking populations respectively. Haplotype G-T constructed of rs668842 and rs11635140 was significantly associated with hypertension comparing to reference haplotype A-C (P = 0.022). Normally distributed square root of TGF-?1 (pg/ml) of hypertension cases (148.56 ± 66.46) was significantly higher than that of control (128.52 ± 65.11), P = 0.008. Furthermore, TGF-?1 was significantly correlated with SBP (r = 0.135, P = 0.018) and DBP (r = 0.154, P = 0.007) respectively whereas no statistical difference of blood pressure or TGF-?1 was observed between genotypes. Remarkably, rs17361868 were significantly associated with the status of blood pressure in the patients taking three of the antihypertensive drugs, Zhen Ju Jiang Ya tablets, Jiang Ya tablet and compound reserpine (P < 0.05). The present study provides further association evidence of FBN1 gene polymorphisms and hypertension, antihypertensive efficacy. Further replication of these results via association or prospective studies conducted in other populations is warranted. PMID:24413999

Chen, Jinfeng; Yang, Song; Zhao, Xianghai; Shen, Jiahui; Wang, Hairu; Chen, Yanchun; Ji, Yanni; Wang, Wen; Zhou, Wei; Wang, Xuecai; Tang, Junming; Lu, Xiangfeng; Chen, Shufeng; Wang, Laiyuan; Li, Hongfan; Shen, Chong; Zhao, Yanping

2014-04-01

264

Association between Polymorphisms in the Renin-Angiotensin-Aldosterone System Genes and Essential Hypertension in the Han Chinese Population  

PubMed Central

Background Renin-angiotensin-aldosterone system (RAAS) is the most important endocrine blood pressure control mechanism in our body, genes encoding components of this system have been strong candidates for the investigation of the genetic basis of hypertension. However, previous studies mainly focused on limited polymorphisms, thus we carried out a case-control study in the Han Chinese population to systemically investigate the association between polymorphisms in the RAAS genes and essential hypertension. Methods 905 essential hypertensive cases and 905 normotensive controls were recruited based on stringent inclusion and exclusion criteria. All 41 tagSNPs within RAAS genes were retrieved from HapMap, and the genotyping was performed using the GenomeLab SNPstream Genotyping System. Logistic regression analysis, Multifactor dimensionality reduction (MDR), stratified analysis and crossover analysis were used to identify and characterize interactions among the SNPs and the non-genetic factors. Results Serum levels of total cholesterol (TC) and triglyceride (TG), and body mass index (BMI) were significantly higher in the hypertensive group than in the control group. Of 41 SNPs genotyped, rs3789678 and rs2493132 within AGT, rs4305 within ACE, rs275645 within AGTR1, rs3802230 and rs10086846 within CYP11B2 were shown to associate with hypertension. The MDR analysis demonstrated that the interaction between BMI and rs4305 increased the susceptibility to hypertension. Crossover analysis and stratified analysis further indicated that BMI has a major effect, and rs4305 has a minor effect. Conclusion These novel findings indicated that together with non-genetic factors, these genetic variants in the RAAS may play an important role in determining an individual’s susceptibility to hypertension in the Han Chinese.

Zhang, Lina; Fei, Lijuan; Wang, Lin; Su, Jia; Lazar, Lissy; Xu, Jin; Zhang, Yaping

2013-01-01

265

Further characterization of a non-essential mutator gene in Escherichia coli K-12.  

PubMed Central

The properties of mutR, a mutator closely linked to thyA, have been further characterized. We have found that the mutator gene is carried on a specialized transducing phage (lambdapcI857 thyA) generated by the excision of lambdacI857 integrated at a secondary attachment site between lysA and thyA. We present three lines of evidence indicating that mutR is a nonessential gene. (i) Deletions of the mutator can be found amoung survivors of heat induction of lambdacI857 when the phage is integrated between lysA and thyA. (ii) Mutations in mutR can be induced with the frameshift mutagen ICR-191. (iii) An amber mutant in mutR has been found. Viable strains could be made by combining the mutator with polB, polA polR, ligts7, and uvrA mutations. The mutator was still able to increase the spontaneous mutation frequency in these genetic backgrounds. When the reversion patterns of a series of well-characterized trpA mutations were analyzed, the results suggested that mutR is more efficient at causing transitions than transversion mutations.

Hoess, R H; Fan, D P

1975-01-01

266

The rpf gene of Micrococcus luteus encodes an essential secreted growth factor  

Microsoft Academic Search

Summary Micrococcus luteus secretes a small protein called Rpf, which has autocrine and paracrine signalling functions and is required for the resuscitation of dor- mant cells. Originally isolated from the supernatant of actively growing cultures, Rpf was also detected on the surface of actively growing bacteria. Most mole- cules may be sequestered non-productively at the cell surface, as a truncated

Galina V. Mukamolova; Obolbek A. Turapov; Konstantin Kazarian; Miroslav Telkov; Arseny S. Kaprelyants; Douglas B. Kell; Michael Young

2002-01-01

267

The Drosophila Clathrin Heavy Chain Gene: Clathrin Function Is Essential in a Multicellular Organism  

PubMed Central

The clathrin heavy chain (HC) is the major structural polypeptide of the cytoplasmic surface lattice of clathrin-coated pits and vesicles. As a genetic approach to understanding the role of clathrin in cellular morphogenesis and developmental signal transduction, a clathrin heavy chain (Chc) gene of Drosophila melanogaster has been identified by a combination of molecular and classical genetic approaches. Using degenerate primers based on mammalian and yeast clathrin HC sequences, a small fragment of the HC gene was amplified from genomic Drosophila DNA by the polymerase chain reaction. Genomic and cDNA clones from phage libraries were isolated and analyzed using this fragment as a probe. The amino acid sequence of the Drosophila clathrin HC deduced from cDNA sequences is 80%, 57% and 49% identical, respectively, with the mammalian, Dictyostelium and yeast HCs. Hybridization in situ to larval polytene chromosomes revealed a single Chc locus at position 13F2 on the X chromosome. A 13-kb genomic Drosophila fragment including the Chc transcription unit was reintroduced into the Drosophila genome via P element-mediated germline transformation. This DNA complemented a group of EMS-induced lethal mutations mapping to the same region of the X chromosome, thus identifying the Chc complementation group. Mutant individuals homozygous or hemizygous for the Chc(1), Chc(2) or Chc(3) alleles developed to a late stage of embryogenesis, but failed to hatch to the first larval stage. A fourth allele, Chc(4), exhibited polyphasic lethality, with a significant number of homozygous and hemizygous offspring surviving to adulthood. Germline clonal analysis of Chc mutant alleles indicated that the three tight lethal alleles were autonomous cell-lethal mutations in the female germline. In contrast, Chc(4) germline clones were viable at a rate comparable to wild type, giving rise to viable adult progeny. However, hemizygous Chc(4) males were invariably sterile. The sterility was efficiently rescued by an autosomal copy of the wild-type Chc gene reintroduced on a P element. These findings suggest a specialized role for clathrin in spermatogenesis.

Bazinet, C.; Katzen, A. L.; Morgan, M.; Mahowald, A. P.; Lemmon, S. K.

1993-01-01

268

Kaposi's Sarcoma-Associated Herpesvirus ORF6 Gene Is Essential in Viral Lytic Replication  

PubMed Central

Kaposi's sarcoma associated herpesvirus (KSHV) is associated with Kaposis's sarcoma (KS), primary effusion lymphoma and multicentric Castleman's disease. KSHV encodes at least 8 open reading frames (ORFs) that play important roles in its lytic DNA replication. Among which, ORF6 of KSHV encodes an ssDNA binding protein that has been proved to participate in origin-dependent DNA replication in transient assays. To define further the function of ORF6 in the virus life cycle, we constructed a recombinant virus genome with a large deletion within the ORF6 locus by using a bacterial artificial chromosome (BAC) system. Stable 293T cells carrying the BAC36 (wild type) and BAC?6 genomes were generated. When monolayers of 293T-BAC36 and 293T-BAC?6 cells were induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) and sodium butyrate, infectious virus was detected from the 293T-BAC36 cell supernatants only and not from the 293T- BAC?6 cell supernatants. DNA synthesis was defective in 293T-BAC?6 cells. Expression of ORF6 in trans in BAC?6-containing cells was able to rescue both defects. Our results provide genetic evidence that ORF6 is essential for KSHV lytic replication. The stable 293T cells carrying the BAC36 and BAC?6 genomes could be used as tools to investigate the detailed functions of ORF6 in the lytic replication of KSHV.

Peng, Can; Chen, Jungang; Tang, Wei; Liu, Chunlan; Chen, Xulin

2014-01-01

269

The Zebrafish fleer Gene Encodes an Essential Regulator of Cilia Tubulin Polyglutamylation  

PubMed Central

Cilia and basal bodies are essential organelles for a broad spectrum of functions, including the development of left-right asymmetry, kidney function, cerebrospinal fluid transport, generation of photoreceptor outer segments, and hedgehog signaling. Zebrafish fleer (flr) mutants exhibit kidney cysts, randomized left-right asymmetry, hydrocephalus, and rod outer segment defects, suggesting a pleiotropic defect in ciliogenesis. Positional cloning flr identified a tetratricopeptide repeat protein homologous to the Caenorhabditis elegans protein DYF1 that was highly expressed in ciliated cells. flr pronephric cilia were shortened and showed a reduced beat amplitude, and olfactory cilia were absent in mutants. flr cilia exhibited ultrastructural defects in microtubule B-tubules, similar to axonemes that lack tubulin posttranslational modifications (polyglutamylation or polyglycylation). flr cilia showed a dramatic reduction in cilia polyglutamylated tubulin, indicating that flr encodes a novel modulator of tubulin polyglutamylation. We also found that the C. elegans flr homologue, dyf-1, is also required for tubulin polyglutamylation in sensory neuron cilia. Knockdown of zebrafish Ttll6, a tubulin polyglutamylase, specifically eliminated tubulin polyglutamylation and cilia formation in olfactory placodes, similar to flr mutants. These results are the first in vivo evidence that tubulin polyglutamylation is required for vertebrate cilia motility and structure, and, when compromised, results in failed ciliogenesis.

Pathak, Narendra; Obara, Tomoko; Mangos, Steve; Liu, Yan

2007-01-01

270

Nuclear factor 1 is essential for the expression of stearoyl-CoA desaturase 1 gene during preadipocyte differentiation.  

PubMed

Stearoyl CoA desaturase gene 1 (SCD1) is a delta 9 desaturase that is transcriptionally activated during the differentiation of 3T3-L1 preadipocytes into adipocytes. We have demonstrated that a SCD1/BP region in SCD1 proximal promoter (-114 to -86 bp) is essential for the transcriptional activation of this gene during differentiation. Mutation in this region abolished the basal activity of the proximal promoter of SCD1, and also failed to induce transcription in response to the differentiation cocktail in transfected cells. The SCD1/BP region contains a TGGCA sequence at -90 bp from the transcription start site. Using competitor oligonucleotides and nuclear factor 1 (NF1)-specific antibodies in gel shift assays, we have shown that in preadipocytes, a NF1 protein binds to this TGGCA sequence. On MDI-induced differentiation of preadipocyte into adipocyte, an additional DNA-protein complex appeared. The appearance of a new NF1 complex is related to the differentiation-specific transcriptional activation of the SCD1 gene. This is the first report to show a differentiation-related change in NF1 protein binding during preadipocyte differentiation. PMID:9689914

Singh, M V; Ntambi, J M

1998-06-16

271

Identification and Characterization of Genes Encoding a Putative ABC-Type Transporter Essential for Utilization of  Hexachlorocyclohexane in Sphingobium japonicum UT26  

Microsoft Academic Search

Sphingobium japonicum UT26 utilizes -hexachlorocyclohexane (-HCH) as its sole source of carbon and energy. In our previous studies, we cloned and characterized genes encoding enzymes for the conversion of -HCH to -ketoadipate in UT26. In this study, we analyzed a mutant obtained by transposon mutagenesis and identified and characterized new genes encoding a putative ABC-type transporter essential for the utilization

Ryo Endo; Yoshiyuki Ohtsubo; Masataka Tsuda; Yuji Nagata

2007-01-01

272

Neuron-Specific Feeding RNAi in C. elegans and Its Use in a Screen for Essential Genes Required for GABA Neuron Function  

PubMed Central

Forward genetic screens are important tools for exploring the genetic requirements for neuronal function. However, conventional forward screens often have difficulty identifying genes whose relevant functions are masked by pleiotropy. In particular, if loss of gene function results in sterility, lethality, or other severe pleiotropy, neuronal-specific functions cannot be readily analyzed. Here we describe a method in C. elegans for generating cell-specific knockdown in neurons using feeding RNAi and its application in a screen for the role of essential genes in GABAergic neurons. We combine manipulations that increase the sensitivity of select neurons to RNAi with manipulations that block RNAi in other cells. We produce animal strains in which feeding RNAi results in restricted gene knockdown in either GABA-, acetylcholine-, dopamine-, or glutamate-releasing neurons. In these strains, we observe neuron cell-type specific behavioral changes when we knock down genes required for these neurons to function, including genes encoding the basal neurotransmission machinery. These reagents enable high-throughput, cell-specific knockdown in the nervous system, facilitating rapid dissection of the site of gene action and screening for neuronal functions of essential genes. Using the GABA-specific RNAi strain, we screened 1,320 RNAi clones targeting essential genes on chromosomes I, II, and III for their effect on GABA neuron function. We identified 48 genes whose GABA cell-specific knockdown resulted in reduced GABA motor output. This screen extends our understanding of the genetic requirements for continued neuronal function in a mature organism.

Firnhaber, Christopher; Hammarlund, Marc

2013-01-01

273

Wild barley eibi1 mutation identifies a gene essential for leaf water conservation.  

PubMed

Drought is a major abiotic stress that limits plant growth and crop productivity. A spontaneous wilty mutant (eibi1) hypersensitive to drought was identified from wild barley (Hordeum spontaneum Koch). eibi1 showed the highest relative water loss rate among the known wilty mutants, which indicates that eibi1 is one of the most drought-sensitive mutants. eibi1 had the same abscisic acid (ABA) level, the same ability to accumulate stress-induced ABA, and the same stomatal movement in response to light, dark, drought, and exogenous ABA as the wild type, revealing that eibi1 was neither an ABA-deficient nor an ABA-insensitive mutant. The eibi1 leaves had a larger chlorophyll efflux rate in 80% ethanol than the wild-type leaves; and the transpiration rate of eibi1 was more closely related to chlorophyll efflux rate than to stomatal density, demonstrating that the cuticle of eibi1 was defective. eibi1 will be a promising candidate to study the actual barrier layer in the cuticle that limits water loss of the plant. Exogenous ABA reduced leaf length growth in eibi1 more than in the wild type, implying an interaction on plant growth of ABA signal transduction and the eibi1 product. One may infer that the eibi1 product may reverse the growth inhibition induced by ABA. PMID:15197591

Chen, Guoxiong; Sagi, Moshe; Weining, Song; Krugman, Tamar; Fahima, Tzion; Korol, Abraham B; Nevo, Eviatar

2004-08-01

274

IGF-I Signaling Is Essential for FSH Stimulation of AKT and Steroidogenic Genes in Granulosa Cells  

PubMed Central

FSH and IGF-I synergistically stimulate gonadal steroid production; conversely, silencing the FSH or the IGF-I genes leads to infertility and hypogonadism. To determine the molecular link between these hormones, we examined the signaling cross talk downstream of their receptors. In human and rodent granulosa cells (GCs), IGF-I potentiated the stimulatory effects of FSH and cAMP on the expression of steroidogenic genes. In contrast, inhibition of IGF-I receptor (IGF-IR) activity or expression using pharmacological, genetic, or biochemical approaches prevented the FSH- and cAMP-induced expression of steroidogenic genes and estradiol production. In vivo experiments demonstrated that IGF-IR inactivation reduces the stimulation of steroidogenic genes and follicle growth by gonadotropins. FSH or IGF-I alone stimulated protein kinase B (PKB), which is also known as AKT and in combination synergistically increased AKT phosphorylation. Remarkably, blocking IGF-IR expression or activity decreased AKT basal activity and abolished AKT activation by FSH. In GCs lacking IGF-IR activity, FSH stimulation of Cyp19 expression was rescued by overexpression of constitutively active AKT. Our findings demonstrate, for the first time, that in human, mouse, and rat GCs, the well-known stimulatory effect of FSH on Cyp19 and AKT depends on IGF-I and on the expression and activation of the IGF-IR.

Zhou, Ping; Baumgarten, Sarah C.; Wu, Yanguang; Bennett, Jill; Winston, Nicola; Hirshfeld-Cytron, Jennifer

2013-01-01

275

Isolation and Characterization of Acetoacetyl-CoA Thiolase Gene Essential for n-Decane Assimilation in Yeast Yarrowia lipolytica  

Microsoft Academic Search

Yarrowia lipolytica is a yeast which can utilize n-alkane as a sole carbon source. We isolated a Y. lipolytica peroxisomal acetoacetyl-CoA thiolase gene, PAT1, by complementation of a mutant that cannot utilize n-decane as a sole carbon source. We found that the putative PAT1 product had conserved features of peroxisomal acetoacetyl-CoA thiolase. We showed that the PAT1 disruptant was not

Setsu Yamagami; Toshiya Iida; Yuji Nagata; Akinori Ohta; Masamichi Takagi

2001-01-01

276

The sf32 Unique Gene of Spodoptera frugiperda Multiple Nucleopolyhedrovirus (SfMNPV) Is a Non-Essential Gene That Could Be Involved in Nucleocapsid Organization in Occlusion-Derived Virions  

PubMed Central

A recombinant virus lacking the sf32 gene (Sf32null), unique to the Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), was generated by homologous recombination from a bacmid comprising the complete viral genome (Sfbac). Transcriptional analysis revealed that sf32 is an early gene. Occlusion bodies (OBs) of Sf32null contained 62% more genomic DNA than viruses containing the sf32 gene, Sfbac and Sf32null-repair, although Sf32null DNA was three-fold less infective when injected in vivo. Sf32null OBs were 18% larger in diameter and contained 17% more nucleocapsids within ODVs than those of Sfbac. No significant differences were detected in OB pathogenicity (50% lethal concentration), speed-of-kill or budded virus production in vivo. In contrast, the production of OBs/larva was reduced by 39% in insects infected by Sf32null compared to those infected by Sfbac. The SF32 predicted protein sequence showed homology (25% identity, 44% similarity) to two adhesion proteins from Streptococcus pyogenes and a single N-mirystoylation site was predicted. We conclude that SF32 is a non-essential protein that could be involved in nucleocapsid organization during ODV assembly and occlusion, resulting in increased numbers of nucleocapsids within ODVs.

Beperet, Ines; Barrera, Gloria; Simon, Oihane; Williams, Trevor; Lopez-Ferber, Miguel; Gasmi, Laila; Herrero, Salvador; Caballero, Primitivo

2013-01-01

277

Enhanced productivity of the essential oil in the artificial autopolyploid of vetiver (Vetiveria zizanioides L. Nash)  

Microsoft Academic Search

Artificial autotetraploids were produced by colchicine treatment in the important essential oil bearing vetiver (2n=20). The raw tetraploids were stabilised by selection for pure types in segregating vegetative progeny. The tetraploids were vigorous with thicker and longer roots. The performance data recorded on 17 months' old crop of the tetraploid taken in conjunction with diploid parent and the best available

U. C. Lavania

1988-01-01

278

NODULE INCEPTION Directly Targets NF-Y Subunit Genes to Regulate Essential Processes of Root Nodule Development in Lotus japonicus  

PubMed Central

The interactions of legumes with symbiotic nitrogen-fixing bacteria cause the formation of specialized lateral root organs called root nodules. It has been postulated that this root nodule symbiosis system has recruited factors that act in early signaling pathways (common SYM genes) partly from the ancestral mycorrhizal symbiosis. However, the origins of factors needed for root nodule organogenesis are largely unknown. NODULE INCEPTION (NIN) is a nodulation-specific gene that encodes a putative transcription factor and acts downstream of the common SYM genes. Here, we identified two Nuclear Factor-Y (NF-Y) subunit genes, LjNF-YA1 and LjNF-YB1, as transcriptional targets of NIN in Lotus japonicus. These genes are expressed in root nodule primordia and their translational products interact in plant cells, indicating that they form an NF-Y complex in root nodule primordia. The knockdown of LjNF-YA1 inhibited root nodule organogenesis, as did the loss of function of NIN. Furthermore, we found that NIN overexpression induced root nodule primordium-like structures that originated from cortical cells in the absence of bacterial symbionts. Thus, NIN is a crucial factor responsible for initiating nodulation-specific symbiotic processes. In addition, ectopic expression of either NIN or the NF-Y subunit genes caused abnormal cell division during lateral root development. This indicated that the Lotus NF-Y subunits can function to stimulate cell division. Thus, transcriptional regulation by NIN, including the activation of the NF-Y subunit genes, induces cortical cell division, which is an initial step in root nodule organogenesis. Unlike the legume-specific NIN protein, NF-Y is a major CCAAT box binding protein complex that is widespread among eukaryotes. We propose that the evolution of root nodules in legume plants was associated with changes in the function of NIN. NIN has acquired functions that allow it to divert pathways involved in the regulation of cell division to root nodule organogenesis.

Soyano, Takashi; Kouchi, Hiroshi; Hirota, Atsuko; Hayashi, Makoto

2013-01-01

279

Pyruvate Decarboxylase Catalyzes Decarboxylation of Branched-Chain 2-Oxo Acids but Is Not Essential for Fusel Alcohol Production by Saccharomyces cerevisiae  

PubMed Central

The fusel alcohols 3-methyl-1-butanol, 2-methyl-1-butanol, and 2-methyl-propanol are important flavor compounds in yeast-derived food products and beverages. The formation of these compounds from branched-chain amino acids is generally assumed to occur via the Ehrlich pathway, which involves the concerted action of a branched-chain transaminase, a decarboxylase, and an alcohol dehydrogenase. Partially purified preparations of pyruvate decarboxylase (EC 4.1.1.1) have been reported to catalyze the decarboxylation of the branched-chain 2-oxo acids formed upon transamination of leucine, isoleucine, and valine. Indeed, in a coupled enzymatic assay with horse liver alcohol dehydrogenase, cell extracts of a wild-type Saccharomyces cerevisiae strain exhibited significant decarboxylation rates with these branched-chain 2-oxo acids. Decarboxylation of branched-chain 2-oxo acids was not detectable in cell extracts of an isogenic strain in which all three PDC genes had been disrupted. Experiments with cell extracts from S. cerevisiae mutants expressing a single PDC gene demonstrated that both PDC1- and PDC5-encoded isoenzymes can decarboxylate branched-chain 2-oxo acids. To investigate whether pyruvate decarboxylase is essential for fusel alcohol production by whole cells, wild-type S. cerevisiae and an isogenic pyruvate decarboxylase-negative strain were grown on ethanol with a mixture of leucine, isoleucine, and valine as the nitrogen source. Surprisingly, the three corresponding fusel alcohols were produced in both strains. This result proves that decarboxylation of branched-chain 2-oxo acids via pyruvate decarboxylase is not an essential step in fusel alcohol production.

ter Schure, Eelko G.; Flikweert, Marcel T.; van Dijken, Johannes P.; Pronk, Jack T.; Verrips, C. Theo

1998-01-01

280

PAS3, a Saccharomyces cerevisiae gene encoding a peroxisomal integral membrane protein essential for peroxisome biogenesis  

PubMed Central

Saccharomyces cerevisiae pas3-mutants are described which conform the pas-phenotype recently reported for the peroxisomal assembly mutants pas1-1 and pas2 (Erdmann, R., M. Veenhuis, D. Mertens, and W.-H Kunau, 1989, Proc. Natl. Acad. Sci. USA. 86:5419-5423). The isolation of pas3- mutants enabled us to clone the PAS3 gene by functional complementation. DNA sequence analysis revealed a 50.6-kD protein with at least one domain of sufficient length and hydrophobicity to span a lipid bilayer. To verify these predictions antibodies were raised against a truncated portion of the PAS3 coding region overexpressed in E. coli. Pas3p was identified as a 48 kD peroxisomal integral membrane protein. It is shown that a lack of this protein causes the peroxisome- deficient phenotype and the cytosolic mislocalization of peroxisomal matrix enzymes. Based on protease digestion experiments Pas3p is discussed to be anchored in the peroxisomal membrane by its amino- terminus while the bulk of the molecule is exposed to the cytosol. These findings are consistent with the possibility that Pas3p is one component of the peroxisomal import machinery.

1991-01-01

281

PLZF Controls the Expression of a Limited Number of Genes Essential for NKT Cell Function  

PubMed Central

Natural killer (NKT) T cells exhibit tissue distribution, surface phenotype, and functional responses that are strikingly different from those of conventional T cells. The transcription factor PLZF is responsible for most of these properties, as its ectopic expression in conventional T cells is sufficient to confer to them an NKT-like phenotype. The molecular program downstream of PLZF, however, is largely unexplored. Here we report that PLZF regulates the expression of a surprisingly small set of genes, many with known immune functions. This includes several established components of the NKT cell developmental program. Expression of the transcriptional regulators Id2, previously shown to be required for iNKT cell survival in the liver and c-Maf, which shapes the NKT cytokine profile, was compromised in PLZF-deficient cells. Ectopic expression of c-Maf complemented the cells’ defect in producing IL-4 and IL-10. PLZF also induced a program of cell surface receptors which shape the NKT cell’s response to external stimuli, including the costimulatory receptor ICOS and the cytokine receptors IL12rb1 and IL18r1. As an ensemble, the known functions of the molecules whose expression is affected by PLZF explain many defects observed in PLZF?/? NKT cells.

Gleimer, Michael; von Boehmer, Harald; Kreslavsky, Taras

2012-01-01

282

Mot1p is essential for TBP recruitment to selected promoters during in vivo gene activation  

PubMed Central

Recruitment of TATA-binding protein (TBP) is central to activation of transcription by RNA polymerase II (pol II). This depends upon co-activator proteins including TBP-associated factors (TAFs). Yeast Mot1p was identified as a general transcriptional repressor in genetic screens and is also found associated with TBP. To obtain insight into Mot1p function in vivo, we determined the mRNA expression profile of the mot1-1 temperature-sensitive (Ts) strain. Unexpectedly, this indicated that Mot1p mostly plays a positive role for transcription. For one potential activation target, HXT2, we analyzed promoter recruitment of Mot1p, TBP, Taf1p (Taf130p) and pol II by chromatin immunoprecipitation assays. Whereas TBP becomes stably associated upon activation of the HXT2 and HXT4 promoters, Mot1p showed only a transient association. TBP recruitment was compromised in two different mot1 mutant strains, but was only moderately affected in a taf1 Ts strain. Together, our data indicate that Mot1p can assist in recruitment of TBP on promoters during gene activation in vivo.

Andrau, Jean-Christophe; Van Oevelen, Chris J.C.; Van Teeffelen, Hetty A.A.M.; Weil, P.Anthony; Holstege, Frank C.P.; Timmers, H.Th.Marc

2002-01-01

283

Focal Adhesion Kinase Signaling Regulates the Expression of Caveolin 3 and ?1 Integrin, Genes Essential for Normal Myoblast Fusion  

PubMed Central

An essential phase of skeletal myogenesis is the fusion of mononucleated myoblasts to form multinucleated myotubes. Many cell adhesion proteins, including integrins, have been shown to be important for myoblast fusion in vertebrates, but the mechanisms by which these proteins regulate cell fusion remain mostly unknown. Here, we focused on the role of focal adhesion kinase (FAK), an important nonreceptor protein tyrosine kinase involved in integrin signaling, as a potential mediator by which integrins may regulate myoblast fusion. To test this hypothesis in vivo, we generated mice in which the Fak gene was disrupted specifically in muscle stem cells (“satellite cells”) and we found that this resulted in impaired myotube formation during muscle regeneration after injury. To examine the role of FAK in the fusion of myogenic cells, we examined the expression of FAK and the effects of FAK deletion on the differentiation of myoblasts in vitro. Differentiation of mouse primary myoblasts was accompanied by a rapid and transient increase of phosphorylated FAK. To investigate the requirement of FAK in myoblast fusion, we used two loss-of-function approaches (a dominant-negative inhibitor of FAK and FAK small interfering RNA [siRNA]). Inhibition of FAK resulted in markedly impaired fusion but did not inhibit other biochemical measures of myogenic differentiation, suggesting a specific role of FAK in the morphological changes of cell fusion as part of the differentiation program. To examine the mechanisms by which FAK may be regulating fusion, we used microarray analysis to identify the genes that failed to be normally regulated in cells that were fusion defective due to FAK inhibition. Several genes that have been implicated in myoblast fusion were aberrantly regulated during differentiation when FAK was inhibited. Intriguingly, the normal increases in the transcript of caveolin 3 as well as an integrin subunit, the ?1D isoform, were suppressed by FAK inhibition. We confirmed this also at the protein level and show that direct inhibition of ?1D subunit expression by siRNA inhibited myotube formation with a prominent effect on secondary fusion. These data suggest that FAK regulation of profusion genes, including caveolin 3 and the ?1D integrin subunit, is essential for morphological muscle differentiation.

Quach, Navaline L.; Biressi, Stefano; Reichardt, Louis F.; Keller, Charles

2009-01-01

284

A viable hypomorphic allele of the essential IMP3 gene reveals novel protein functions in Saccharomyces cerevisiae.  

PubMed

In Saccharomyces cerevisiae, the essential IMP3 gene encodes a component of the SSU processome, a large ribonucleoprotein complex required for processing of small ribosomal subunit RNA precursors. Mutation of the IMP3 termination codon to a sense codon resulted in a viable mutant allele producing a C-terminal elongated form of the Imp3 protein. A strain expressing the mutant allele displayed ribosome biogenesis defects equivalent to IMP3 depletion. This hypomorphic allele represented a unique opportunity to investigate and better understand the Imp3p functions. We demonstrated that the +1 frameshifting was increased in the mutant strain. Further characterizations revealed involvement of the Imp3 protein in DNA repair and telomere length control, pointing to a functional relationship between both pathways and ribosome biogenesis. PMID:21559332

Cosnier, Bruno; Kwapisz, Marta; Hatin, Isabelle; Namy, Olivier; Hermann-Le Denmat, Sylvie; Morillon, Antonin; Rousset, Jean-Pierre; Fabret, Céline

2011-01-01

285

Mouse gene targeting reveals an essential role of mTOR in hematopoietic stem cell engraftment and hematopoiesis  

PubMed Central

mTOR integrates signals from nutrients and growth factors to control protein synthesis, cell growth, and survival. Although mTOR has been established as a therapeutic target in hematologic malignancies, its physiological role in regulating hematopoiesis remains unclear. Here we show that conditional gene targeting of mTOR causes bone marrow failure and defects in multi-lineage hematopoiesis including myelopoiesis, erythropoiesis, thrombopoiesis, and lymphopoiesis. mTOR deficiency results in loss of quiescence of hematopoietic stem cells, leading to a transient increase but long-term exhaustion and defective engraftment of hematopoietic stem cells in lethally irradiated recipient mice. Furthermore, ablation of mTOR causes increased apoptosis in lineage-committed blood cells but not hematopoietic stem cells, indicating a differentiation stage-specific function. These results demonstrate that mTOR is essential for hematopoietic stem cell engraftment and multi-lineage hematopoiesis.

Guo, Fukun; Zhang, Shuangmin; Grogg, Matthew; Cancelas, Jose A.; Varney, Melinda E.; Starczynowski, Daniel T.; Du, Wei; Yang, Jun-Qi; Liu, Wei; Thomas, George; Kozma, Sara; Pang, Qishen; Zheng, Yi

2013-01-01

286

Drosophila liquid facets-Related encodes Golgi epsin and is an essential gene required for cell proliferation, growth, and patterning  

PubMed Central

Epsin and epsin-Related (epsinR) are multi-modular proteins that stimulate clathrin-coated vesicle formation. Epsin promotes endocytosis at the plasma membrane, and epsinR functions at the Golgi and early endosomes for trans-Golgi network/endosome vesicle trafficking. In Drosophila, endocytic epsin is known as Liquid facets, and it is essential specifically for Notch signaling. Here, by generating and analyzing loss-of-function mutants in the liquid facets-Related (lqfR) gene of Drosophila, we investigated the function of Golgi epsin in a multicellular context. We found that LqfR is indeed a Golgi protein, and that like liquid facets, lqfR is essential for Drosophila viability. In addition, primarily by analyzing mutant eye discs, we found that lqfR is required for cell proliferation, insulin-independent cell growth, and cell patterning, consistent with a role in one or several signaling pathways. Epsins in all organisms share an ENTH (epsin N-terminal homology) domain, which binds phosphoinositides enriched at the plasma membrane or the Golgi membrane. The epsinR ENTH domain is also the recognition element for particular cargos. By generating wild-type and mutant lqfR transgenes, we found that all apparent LqfR functions are independent of its ENTH domain. These results suggest that LqfR transports specific cargo critical to one or more signaling pathways, and lays the foundation for identifying those proteins.

Lee, Ji-Hoon; Overstreet, Erin; Fitch, Erin; Fleenor, Stephen; Fischer, Janice

2009-01-01

287

Functional Characterization of MAT1-1-Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators?†  

PubMed Central

Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular basis of homothallism and the role of mating-type genes during fruiting-body development, we deleted each of the three genes, SmtA-1 (MAT1-1-1), SmtA-2 (MAT1-1-2), and SmtA-3 (MAT1-1-3), contained in the MAT1-1 part of the mating-type locus of the homothallic ascomycete species Sordaria macrospora. Phenotypic analysis of deletion mutants revealed that the PPF domain protein-encoding gene SmtA-2 is essential for sexual reproduction, whereas the ? domain protein-encoding genes SmtA-1 and SmtA-3 play no role in fruiting-body development. By means of cross-species microarray analysis using Neurospora crassa oligonucleotide microarrays hybridized with S. macrospora targets and quantitative real-time PCR, we identified genes expressed under the control of SmtA-1 and SmtA-2. Both genes are involved in the regulation of gene expression, including that of pheromone genes.

Klix, V.; Nowrousian, M.; Ringelberg, C.; Loros, J. J.; Dunlap, J. C.; Poggeler, S.

2010-01-01

288

Isolation and identification of precocenes and piperitone from essential oils as specific inhibitors of trichothecene production by Fusarium graminearum.  

PubMed

Inhibitors of deoxynivalenol production by Fusarium graminearum are useful for protecting crops from deoxynivalenol contamination. We isolated precocenes and piperitone from the essential oils of Matricaria recutita and Eucalyptus dives, respectively, as specific inhibitors of the production of 3-acetyldeoxynivalenol, a biosynthetic precursor of deoxynivalenol. Precocenes I and II and piperitone inhibited 3-acetyldeoxynivalenol production by F. graminearum in a liquid culture with IC(50) values of 16.6, 1.2, and 306 microM, respectively, without inhibiting fungal growth. Precocene II also inhibited deoxynivalenol production by the fungus in a solid culture on rice with an IC(50) value of 2.0 ppm. Precocene II and piperitone decreased the mRNA levels of Tri4, Tri5, Tri6, and Tri10 encoding proteins required for deoxynivalenol biosynthesis. PMID:19191669

Yaguchi, Atsushi; Yoshinari, Tomoya; Tsuyuki, Rie; Takahashi, Haruo; Nakajima, Takashi; Sugita-Konishi, Yoshiko; Nagasawa, Hiromichi; Sakuda, Shohei

2009-02-11

289

Identification of the phosphoglycerate dehydrogenase isoform EDA9 as the essential gene for embryo and male gametophyte development in Arabidopsis  

PubMed Central

Three different pathways of serine (Ser) biosynthesis have been described in plants: the Glycolate pathway, which is part of the Photorespiratory pathway, and 2 non-Photorespiratory pathways, the Glycerate and the Phosphorylated pathways. The Phosphorylated Pathway of Ser Biosynthesis (PPSB) has been known to exist since the 1950s, but its biological relevance was not revealed until quite recently when the last enzyme of the pathway, the Phosphoserine Phosphatase, was functionally characterized. In the associated study1, we characterized a family of genes coding for putatite phosphoglycerate dehydrogenases (PGDH, 3-PGDH, and EDA9), the first enzyme of the PPSB. A metabolomics study using overexpressing plants indicated that all PGDH family genes were able to regulate Ser homeostasis but only lacking of EDA9 expression caused drastic developmental defects. We provided genetic and molecular evidence for the essential role of EDA9 for embryo and pollen development. Here, some new insights into the physiological/molecular function of PPSB and Ser are presented and discussed.

Toujani, Walid; Munoz-Bertomeu, Jesus; Flores-Tornero, Maria; Rosa-Tellez, Sara; Anoman, Armand Djoro; Ros, Roc

2013-01-01

290

Evidence that trypanothione reductase is an essential enzyme in Leishmania by targeted replacement of the tryA gene locus.  

PubMed

Trypanothione reductase (TR), a flavoprotein oxidoreductase central to the unique thiol-redox system that operates in trypanosomatid protozoa, has been proposed as a potential target for the chemotherapy of trypanosomatid infections. In this study, targeted gene replacement was used to obtain evidence that TR is an essential cellular component and that its physiological function is crucial for parasite survival. Precise replacement of the Leishmania donovani tryA gene encoding TR was only possible upon simultaneous expression of the tryA coding region from an episome; in its absence, attempted removal of the last tryA allele invariably led to the generation of an extra copy of tryA, seemingly as a result of selective chromosomal polysomy. Partial replacement mutants were drastically affected in their ability to survive inside cytokine-activated macrophages in a murine model of Leishmania infection. As no compensatory mechanism for the partial loss of TR activity was observed in these mutants and as it was not possible to obtain viable Leishmania devoid of TR catalytic activity, specific inhibitors of this enzyme are likely to be useful anti-leishmanial agents for chemotherapeutic use. PMID:9720880

Tovar, J; Wilkinson, S; Mottram, J C; Fairlamb, A H

1998-07-01

291

Characterization of the Vibrio alginolyticusfur gene and localization of essential amino acid sites in fur by site-directed mutagenesis.  

PubMed

The expression of iron-regulated genes in bacteria is typically controlled by the ferric uptake regulator (Fur) protein, a global transcriptional repressor that regulates functions as diverse as iron acquisition, oxidative stress, virulence and acid tolerance. We have identified a fur homologue in Vibrio alginolyticus and shown that it complements an Escherichia coli fur mutant. Reverse transcriptase PCR (RT-PCR) analysis proved that unlike many other fur homologues, V. alginolyticusfur is not under the iron-response Fur autoregulation. Homology modeling of the V. alginolyticus Fur protein with the recently solved crystal structure of Fur from Pseudomonas aeruginosa indicated extensive structural conservation. Based on the highly conserved DNA-binding sites and metal-binding sites in Fur protein, a series of site-directed mutations were respectively introduced into the cloned V. alginolyticus fur gene and resulted in partial or complete loss of Fur repressor function. Mutations in H33 and H90 were associated with complete loss of Fur function, mutations in Y56, R57, H87, C93 and H125 were related to partial loss of Fur function, and mutations in C96 and C133 did not show obvious change of Fur function. Our studies allowed the localization of some essential amino acid sites which may play important structural or functional roles in V. alginolyticus Fur activity. PMID:17693709

Liu, Qin; Wang, Pengbo; Ma, Yue; Zhang, Yuanxing

2007-01-01

292

Pathogens and gene product normalization in the biomedical literature.  

PubMed

We present a new approach for pathogens and gene product normalization in the biomedical literature. The idea of this approach was motivated by needs such as literature curation, in particular applied to the field of infectious diseases thus, variants of bacterial species (S. aureus, Staphyloccocus aureus, ...) and their gene products (protein ArsC, Arsenical pump modifier, Arsenate reductase, ...). Our approach is based on the use of an Ontology Look-up Service, a Gene Ontology Categorizer (GOCat) and Gene Normalization methods. In the pathogen detection task the use of OLS disambiguates found pathogen names. GOCat results are incorporated into overall score system to support and to confirm the decisionmaking in normalization process of pathogens and their genomes. The evaluation was done on two test sets of BioCreativeIII benchmark: gold standard of manual curation (50 articles) and silver standard (507 articles) curated by collective results of BCIII participants. For the cross-species GN we achieved the precision of 46% for silver and 27% for gold sets. Pathogen normalization results showed 95% of precision and 93% of recall. The impact of GOCat explicitly improves results of pathogen and gene normalization, basically confirming identified pathogens and boosting correct gene identifiers on the top of the results' list ranked by confidence. A correct identification of the pathogen is able to improve significantly normalization effectiveness and to solve the disambiguation problem of genes. PMID:22491118

Vishnyakova, Dina; Pasche, Emilie; Teodoro, Douglas; Lovis, Christian; Ruch, Patrick

2012-01-01

293

Anode Biofilm Transcriptomics Reveals Outer Surface Components Essential for High Density Current Production in Geobacter sulfurreducens Fuel Cells  

PubMed Central

The mechanisms by which Geobacter sulfurreducens transfers electrons through relatively thick (>50 µm) biofilms to electrodes acting as a sole electron acceptor were investigated. Biofilms of Geobacter sulfurreducens were grown either in flow-through systems with graphite anodes as the electron acceptor or on the same graphite surface, but with fumarate as the sole electron acceptor. Fumarate-grown biofilms were not immediately capable of significant current production, suggesting substantial physiological differences from current-producing biofilms. Microarray analysis revealed 13 genes in current-harvesting biofilms that had significantly higher transcript levels. The greatest increases were for pilA, the gene immediately downstream of pilA, and the genes for two outer c-type membrane cytochromes, OmcB and OmcZ. Down-regulated genes included the genes for the outer-membrane c-type cytochromes, OmcS and OmcT. Results of quantitative RT-PCR of gene transcript levels during biofilm growth were consistent with microarray results. OmcZ and the outer-surface c-type cytochrome, OmcE, were more abundant and OmcS was less abundant in current-harvesting cells. Strains in which pilA, the gene immediately downstream from pilA, omcB, omcS, omcE, or omcZ was deleted demonstrated that only deletion of pilA or omcZ severely inhibited current production and biofilm formation in current-harvesting mode. In contrast, these gene deletions had no impact on biofilm formation on graphite surfaces when fumarate served as the electron acceptor. These results suggest that biofilms grown harvesting current are specifically poised for electron transfer to electrodes and that, in addition to pili, OmcZ is a key component in electron transfer through differentiated G. sulfurreducens biofilms to electrodes.

Glaven, Richard H.; Johnson, Jessica P.; Woodard, Trevor L.; Methe, Barbara A.; DiDonato, Raymond J.; Covalla, Sean F.; Franks, Ashley E.; Liu, Anna; Lovley, Derek R.

2009-01-01

294

Gene Discovery and Product Development for Grain Quality Traits  

NSDL National Science Digital Library

The composition of oils, proteins, and carbohydrates in seeds of corn, soybean, and other crops has been modified to produce grains with enhanced value. Both plant breeding and molecular technologies have been used to produce plants carrying the desired traits. Genomics-based strategies for gene discovery, coupled with high-throughput transformation processes and miniaturized, automated analytical and functionality assays, have accelerated the identification of product candidates. Molecular markerâÂÂbased breeding strategies have been used to accelerate the process of moving trait genes into high-yielding germplasm for commercialization. These products are being tested for applications in food, feed, and industrial markets.

Barbara Mazur (DuPont Agricultural Products Experimental Station;); Enno Krebers (DuPont Agricultural Products Experimental Station;); Scott Tingey (DuPont Agricultural Products Experimental Station;)

1999-07-16

295

Methylenetetrahydrofolate reductase C677T gene polymorphism and essential hypertension: A meta-analysis of 10,415 subjects  

PubMed Central

The methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism has been suggested to be associated with the risk of essential hypertension (EH), however, results remain inconclusive. To investigate this association, the present meta-analysis of 27 studies including 5,418 cases and 4,997 controls was performed. The pooled odds ratio (OR) and its corresponding 95% confidence interval were calculated using the random-effects model. A significant association between the MTHFR C677T gene polymorphism and EH was found under the allelic (OR, 1.32; 95% CI, 1.20–1.45; P=0.000), dominant (OR, 1.39; 95% CI, 1.25–1.55; P=0.000), recessive (OR, 1.38; 95% CI, 1.18–1.62; P=0.000), homozygote (OR, 1.59; 95% CI, 1.32–1.92; P=0.000), and heterozygote (OR, 1.32; 95% CI, 1.20–1.45; P=0.000) genetic models. A strong association was also revealed in subgroups, including Asian, Caucasian and Chinese. The Japanese subgroup did not show any significant association under all models. Meta-regression analyses suggested that the study design was a potential source of heterogeneity, whereas the subgroup analysis additionally indicated that the population origin may also be an explanation. Another subgroup analysis revealed that hospital-based studies have a stronger association than population-based studies, however, the former suffered a greater heterogeneity. Funnel plot and Egger’s test manifested no evidence of publication bias. In conclusion, the present study supports the evidence for the association between the MTHFR C677T gene polymorphism and EH in the whole population, as well as in subgroups, such as Asian, Caucasian and Chinese. The carriers of the 677T allele are susceptible to EH.

YANG, KE-MING; JIA, JIAN; MAO, LI-NA; MEN, CHEN; TANG, KANG-TING; LI, YAN-YAN; DING, HAI-XIA; ZHAN, YI-YANG

2014-01-01

296

Effects of Cymbopogon citratus L. essential oil on the growth, morphogenesis and aflatoxin production of Aspergillus flavus ML2-strain.  

PubMed

The mycelial growth of Aspergillus flavus Link was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek's liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 65% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. flavus hyphae after treatment with C. citratus essential oil. The hyphal diameter decreased and hyphal wall appeared as precipitates and disappeared in some regions. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca(+2), K(+) and Mg(+2) leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated and unsaturated fatty acids increased. One of the most important results obtained during this study was the ability of C. citratus essential oil at its sublethal dose to completely inhibit aflatoxin B(1) production from A. flavus. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegradation and storage contaminating fungi and also in fruit juice preservation. PMID:17304618

Helal, G A; Sarhan, M M; Abu Shahla, A N K; Abou El-Khair, E K

2007-02-01

297

Chemoprevention by essential oil of turmeric leaves (Curcuma longa L.) on the growth of Aspergillus flavus and aflatoxin production.  

PubMed

Turmeric is well known for a wide range of medicinal properties. Essential oil of turmeric leaves (Curcuma longa L.) were evaluated at varying concentrations of 0.01, 0.05, 0.1, 0.5, 0.75, 1.0 and 1.5% (v/v) in Yeast Extract Sucrose (YES) broth inoculated with spore suspension of Aspergillus flavus of 10(6)conidia/ml. These were evaluated for their potential in the control of aflatoxigenic fungus A. flavus and aflatoxin production. Turmeric leaf oil exhibited 95.3% and 100% inhibition of toxin production respectively at 1.0% and 1.5%. The extent of inhibition of fungal growth and aflatoxin production was dependent on the concentration of essential oil used. The oil exhibited significant inhibition of fungal growth as well as aflatoxins B(1) and G(1) production. The LD(50) and LD(90) were also determined. GC-MS analysis of the oil showed ?-phellandrene, p-cymene and terpinolene as the major components in turmeric leaf oil. The possibility of using these phytochemical components as bio-preservatives for storage of spices is discussed. PMID:21354246

Sindhu, S; Chempakam, B; Leela, N K; Suseela Bhai, R

2011-05-01

298

The deletion polymorphism of the angiotensin I-converting enzyme gene is associated with target organ damage in essential hypertension.  

PubMed

The activity of the renin-angiotensin-aldosterone system is thought to play a significant role in the development of target organ damage in essential hypertension. An insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene has recently been associated with increased risk for left ventricular hypertrophy and coronary heart disease in the general population. The D allele is associated with higher levels of circulating ACE and therefore may predispose to cardiovascular damage. The study presented here was performed to investigate the association between the ACE genotype, microalbuminuria, retinopathy, and left ventricular hypertrophy in 106 patients with essential hypertension. ACE gene polymorphism was determined by polymerase chain reaction technique. Microalbuminuria was evaluated as albumin-to-creatinine ratio (A/C) in three nonconsecutive first morning urine samples (negative urine culture) after a 4-wk washout period. Microalbuminuria was defined as A/C between 2.38 to 19 (men) and 2.96 to 20 (women). Hypertensive retinopathy was evaluated by direct funduscopic examination (keith-Wagener-Barker classification) and left ventricular hypertrophy by M-B mode echocardiography. The distribution of the DD, ID, and II genotypes was 27, 50, and 23%, respectively. The prevalence of microalbuminuria, retinopathy, and left ventricular hypertrophy was 19, 74, and 72% respectively. There were no differences among the three genotypes for age, known duration of disease, body mass index, blood pressure, serum glucose, uric acid, and lipid profile. DD and ID genotypes were significantly associated with the presence of microalbuminuria (odds ratio, 8.51; 95% confidence interval, 1.07 to 67.85; P = 0.019), retinopathy (odds ratio, 5.19; 95% confidence interval, 1.71 to 15.75; P = 0.005) and left ventricular hypertrophy (odds ratio, 5.22; 95% confidence interval, 1.52 to 17.94; P = 0.016). Furthermore, patients with DD and ID genotypes showed higher levels of A/C (3.6 +/- 0.9, DD; 2.6 +/- 0.7, ID; 0.9 +/- 0.2 mg/mmol, II; P = 0.0015 by analysis of variance) and increased left ventricular mass index (152 +/- 4.7, DD + ID versus 133 +/- 5.7 g/m2, II; P = 0.01) compared with II patients. The D allele was significantly more frequent in patients with microalbuminuria (odds ratio, 2.59; 95% confidence interval, 1.24 to 5.41; P = 0.013) and in those with retinopathy (odds ratio, 2.44; 95% confidence interval, 1.21 to 4.90; P = 0.015). Multiple regression analyses performed among the entire cohort of patients demonstrated that ACE genotype significantly and independently influences the presence of retinopathy, left ventricular hypertrophy, and microalbuminuria. In conclusion, the D allele of the ACE gene is associated with microalbuminuria as well as with retinopathy and left ventricular hypertrophy, and seems to be an independent risk factor for target organ damage in essential hypertension. PMID:8989733

Pontremoli, R; Sofia, A; Tirotta, A; Ravera, M; Nicolella, C; Viazzi, F; Bezante, G P; Borgia, L; Bobola, N; Ravazzolo, R; Sacchi, G; Deferrari, G

1996-12-01

299

Gene technology, food production, and public opinion: A UK study  

Microsoft Academic Search

In this paper, dimensions of the debate surrounding the application of gene technology to food production are discussed and a study assessing perceptions of the technology among a sample of the UK public (n = 1499) is reported. The general picture that emerges from the study is one of people expressing low familiarity with the technology, with more people associating

Paul Sparks; Richard Shepherd; Lynn J. Frewer

1994-01-01

300

Identification and amplification of the E. coli phr gene product.  

PubMed Central

We have constructed a series of multicopy plasmids that complement mutations in the phr gene of Escherichia coli. By subcloning into a tac plasmid vector we obtained a phr plasmid that upon induction overproduces two proteins of Mr's 49,000 and 20,000. Tn1000 insertions into the phr gene caused the disappearance of the 49,000 dalton protein, thus demonstrating this protein to be the phr gene product, DNA photolyase. The photolyase encoded by the phr gene makes up about 15% of total cellular proteins after induction of cells carrying a tac-phr plasmid. This protein binds specifically to UV (254 nm) irradiated DNA and upon exposure to near UV (300-500 nm) illumination repairs the UV damage and dissociates from DNA. Images

Sancar, G B; Smith, F W; Sancar, A

1983-01-01

301

An integrated approach utilising chemometrics and GC/MS for classification of chamomile flowers, essential oils and commercial products.  

PubMed

As part of an ongoing research program on authentication, safety and biological evaluation of phytochemicals and dietary supplements, an in-depth chemical investigation of different types of chamomile was performed. A collection of chamomile samples including authenticated plants, commercial products and essential oils was analysed by GC/MS. Twenty-seven authenticated plant samples representing three types of chamomile, viz. German chamomile, Roman chamomile and Juhua were analysed. This set of data was employed to construct a sample class prediction (SCP) model based on stepwise reduction of data dimensionality followed by principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The model was cross-validated with samples including authenticated plants and commercial products. The model demonstrated 100.0% accuracy for both recognition and prediction abilities. In addition, 35 commercial products and 11 essential oils purported to contain chamomile were subsequently predicted by the validated PLS-DA model. Furthermore, tentative identification of the marker compounds correlated with different types of chamomile was explored. PMID:24444953

Wang, Mei; Avula, Bharathi; Wang, Yan-Hong; Zhao, Jianping; Avonto, Cristina; Parcher, Jon F; Raman, Vijayasankar; Zweigenbaum, Jerry A; Wylie, Philip L; Khan, Ikhlas A

2014-06-01

302

Neoplastic transformation of rat thyroid cells requires the junB and fra-1 gene induction which is dependent on the HMGI-C gene product.  

PubMed

The expression of the high mobility group I (HMGI)-C chromatin component was shown previously to be essential for the establishment of the neoplastic phenotype in retrovirally transformed thyroid cell lines. To identify possible targets of the HMGI-C gene product, we have analyzed the AP-1 complex in normal, fully transformed and antisense HMGI-C-expressing rat thyroid cells. We show that neoplastic transformation is associated with a drastic increase in AP-1 activity, which reflects multiple compositional changes. The strongest effect is represented by the dramatic junB and fra-1 gene induction, which is prevented in cell lines expressing the antisense HMGI-C. These results indicate that the HMGI-C gene product is essential for the junB and fra-1 transcriptional induction associated with neoplastic transformation. The inhibition of Fra-1 protein synthesis by stable transfection with a fra-1 antisense RNA vector significantly reduces the malignant phenotype of the transformed thyroid cells, indicating a pivotal role for the fra-1 gene product in the process of cellular transformation. PMID:9311991

Vallone, D; Battista, S; Pierantoni, G M; Fedele, M; Casalino, L; Santoro, M; Viglietto, G; Fusco, A; Verde, P

1997-09-01

303

Neoplastic transformation of rat thyroid cells requires the junB and fra-1 gene induction which is dependent on the HMGI-C gene product.  

PubMed Central

The expression of the high mobility group I (HMGI)-C chromatin component was shown previously to be essential for the establishment of the neoplastic phenotype in retrovirally transformed thyroid cell lines. To identify possible targets of the HMGI-C gene product, we have analyzed the AP-1 complex in normal, fully transformed and antisense HMGI-C-expressing rat thyroid cells. We show that neoplastic transformation is associated with a drastic increase in AP-1 activity, which reflects multiple compositional changes. The strongest effect is represented by the dramatic junB and fra-1 gene induction, which is prevented in cell lines expressing the antisense HMGI-C. These results indicate that the HMGI-C gene product is essential for the junB and fra-1 transcriptional induction associated with neoplastic transformation. The inhibition of Fra-1 protein synthesis by stable transfection with a fra-1 antisense RNA vector significantly reduces the malignant phenotype of the transformed thyroid cells, indicating a pivotal role for the fra-1 gene product in the process of cellular transformation.

Vallone, D; Battista, S; Pierantoni, G M; Fedele, M; Casalino, L; Santoro, M; Viglietto, G; Fusco, A; Verde, P

1997-01-01

304

Association of Insertion\\/Deletion Polymorphism of Alpha-Adrenoceptor Gene in Essential Hypertension with or without Type 2 Diabetes Mellitus in Malaysian Subjects  

Microsoft Academic Search

An insertion\\/deletion (I\\/D) polymorphism of Alpha2B-Adrenoceptor (ADRA2B) gene located on chromosome 2 has been studied extensively in related to cardiovascular diseases. The main aim of the present study was to examine the potential association of D allele frequency of I\\/D polymorphism of ADRA2B gene in Malaysian essential hypertensive subjects with or without type 2 diabetes mellitus (T2DM). This study includes

R. Vasudevan; Patimah Ismail; Johnson Stanslas; Norashikin Shamsudin

305

Gene expression profiling distinguishes JAK2V617F-negative from JAK2V617F-positive patients in essential thrombocythemia  

Microsoft Academic Search

To explore the gene expression signature in essential thrombocythemia (ET) patients in relation to JAK2V617F mutational status, expression profiling in circulating granulocytes was performed. Twenty ET were studied by microarray analysis and the results were confirmed by real-time quantitative RT-PCR in 40 ET patients, not receiving cytoreductive treatment. A heterogeneous molecular signature characterized by two main gene expression patterns was

E Puigdecanet; B Espinet; J J Lozano; L Sumoy; B Bellosillo; L Arenillas; A Álvarez-Larrán; F Solé; S Serrano; C Besses; L Florensa

2008-01-01

306

Association of Angiotensin II Type 1 Receptor (A1166C) Gene Polymorphism and Its Increased Expression in Essential Hypertension: A Case-Control Study  

PubMed Central

Objectives Hypertension is one of the major cardiovascular diseases. It affects nearly 1.56 billion people worldwide. The present study is about a particular genetic polymorphism (A1166C), gene expression and protein expression of the angiotensin II type I receptor (AT1R) (SNP ID: rs5186) and its association with essential hypertension in a Northern Indian population. Methods We analyzed the A1166C polymorphism and expression of AT1R gene in 250 patients with essential hypertension and 250 normal healthy controls. Results A significant association was found in the AT1R genotypes (AC+CC) with essential hypertension (?2?=?22.48, p?=?0.0001). Individuals with CC genotypes were at 2.4 times higher odds (p?=?0.0001) to develop essential hypertension than individuals with AC and AA genotypes. The statistically significant intergenotypic variation in the systolic blood pressure was found higher in the patients with CC (169.4±36.3 mmHg) as compared to that of AA (143.5±28.1 mmHg) and AC (153.9±30.5 mmHg) genotypes (p?=?0.0001). We found a significant difference in the average delta-CT value (p?=?0.0001) wherein an upregulated gene expression (approximately 16 fold) was observed in case of patients as compared to controls. Furthermore, higher expression of AT1R gene was observed in patients with CC genotype than with AC and AA genotypes. A significant difference (p?=?0.0001) in the protein expression of angiotensin II Type 1 receptor was also observed in the plasma of patients (1.49±0.27) as compared to controls (0.80±0.24). Conclusion Our findings suggest that C allele of A1166C polymorphism in the angiotensin II type 1 receptor gene is associated with essential hypertension and its upregulation could play an important role in essential hypertension.

Chandra, Sudhir; Narang, Rajiv; Sreenivas, Vishnubhatla; Bhatia, Jagriti; Saluja, Daman; Srivastava, Kamna

2014-01-01

307

A novel competence gene, comP, is essential for natural transformation of Acinetobacter sp. strain BD413.  

PubMed Central

Acinetobacter sp. strain BD413 (= ATCC 33305), a nutritionally versatile bacterium, has an extremely efficient natural transformation system. Here we describe the generation of eight transformation-affected mutants of Acinetobacter sp. strain BD413 by insertional mutagenesis. These mutants were found by Southern blot analysis and complementation studies to result from single nptII marker insertions at different chromosomal loci. DNA binding and uptake studies with one mutant, T205, revealed that the transformation deficiency of this mutant results from a complete lack of DNA binding and, therefore, uptake activity. A novel competence gene essential for natural transformation, named comP, was cloned by complementation of mutant T205. The nucleotide sequence of comP was determined, and its deduced 15-kDa polypeptide displays significant similarities to type IV pilins. Analysis of the ultrastructure of a transformation-deficient comP mutant and the transformation-competent wild-type strain revealed that both are covered with bundle-forming thin fimbriae (3 to 4 nm in diameter) and individual thick fimbriae (6 nm in diameter). These results provide evidence that the pilinlike ComP is unrelated to the piluslike structures of strain BD413. Taking all data into account, we propose that ComP functions as a major subunit of an organelle acting as a channel or pore mediating DNA binding and/or uptake in Acinetobacter sp. strain BD413.

Porstendorfer, D; Drotschmann, U; Averhoff, B

1997-01-01

308

Gene targeting reveals the role of Oc90 as the essential organizer of the otoconial organic matrix  

PubMed Central

A critical part of the functional development of our peripheral balance system is the embryonic formation of otoconia, composite crystals that overlie and provide optimal stimulus input to the sensory epithelium of the gravity receptor in the inner ear. To date neither the functions of otoconial proteins nor the processes of crystal formation are clearly defined. Using gene targeting and protein analysis strategies, we demonstrate that the predominant mammalian otoconin, otoconin-90/95 (Oc90), is essential for formation of the organic matrix of otoconia by specifically recruiting other matrix components, which includes otolin, a novel mammalian otoconin that we identified to be in wildtype murine otoconia. We show that this matrix controls otoconia growth and morphology by embedding the crystallites during seeding and growth. During otoconia development, the organic matrix forms prior to CaCO3 deposition and provides optimal calcification efficiency. Histological and ultrastructural examinations show normal inner ear epithelial morphology but reduced acellular matrices, including otoconial, cupular and tectorial membranes, in Oc90 null mice, likely due to an absence of Oc90 and a profound reduction of otolin. Our data demonstrate the critical roles of otoconins in otoconia seeding, growth and anchoring and suggest mechanistic similarities and differences between otoconia and bone calcification.

Zhao, Xing; Yang, Hua; Yamoah, Ebenezer N; Lundberg, Yunxia Wang

2007-01-01

309

A Novel Tetrahydrofolate-Dependent O-Demethylase Gene Is Essential for Growth of Sphingomonas paucimobilis SYK-6 with Syringate  

PubMed Central

Sphingomonas paucimobilis SYK-6 degrades syringate to 3-O-methylgallate (3MGA), which is finally converted to pyruvate and oxaloacetate via multiple pathways in which protocatechuate 4,5-dioxygenase, 3MGA dioxygenase, and gallate dioxygenase are involved. Here we isolated the syringate O-demethylase gene (desA), which complemented the growth deficiency on syringate of a Tn5 mutant of the SYK-6 derivative strain. The desA gene is located 929 bp downstream of ferA, encoding feruloyl-coenzyme A synthetase, and consists of a 1,386-bp open reading frame encoding a polypeptide with a molecular mass of 50,721 Da. The deduced amino acid sequence of desA showed 26% identity in a 325-amino-acid overlap with that of gcvT of Escherichia coli, which encodes the tetrahydrofolate (H4folate)-dependent aminomethyltransferase involved in glycine cleavage. The cell extract of E. coli carrying desA converted syringate to 3MGA only when H4folate was added to the reaction mixture. DesA catalyzes the transfer of the methyl moiety of syringate to H4folate, forming 5-methyl-H4folate. Vanillate and 3MGA were also used as substrates for DesA; however, the relative activities toward them were 3 and 0.4% of that toward syringate, respectively. Disruption of desA in SYK-6 resulted in a growth defect on syringate but did not affect growth on vanillate, indicating that desA is essential to syringate degradation. In a previous study the ligH gene, which complements the growth deficiency on vanillate and syringate of a chemical-induced mutant of SYK-6, DC-49, was isolated (S. Nishikawa, T. Sonoki, T. Kasahara, T. Obi, S. Kubota, S. Kawai, N. Morohoshi, and Y. Katayama, Appl. Environ. Microbiol. 64:836-842, 1998). Disruption of ligH resulted in the same phenotype as DC-49; its cell extract, however, was found to be able to convert vanillate and syringate in the presence of H4folate. The possible role of ligH is discussed.

Masai, Eiji; Sasaki, Miyuki; Minakawa, Yasunori; Abe, Tomokuni; Sonoki, Tomonori; Miyauchi, Keisuke; Katayama, Yoshihiro; Fukuda, Masao

2004-01-01

310

Fatty Acid Oxidation Is Essential for Egg Production by the Parasitic Flatworm Schistosoma mansoni  

PubMed Central

Schistosomes, parasitic flatworms that cause the neglected tropical disease schistosomiasis, have been considered to have an entirely carbohydrate based metabolism, with glycolysis playing a dominant role in the adult parasites. However, we have discovered a close link between mitochondrial oxygen consumption by female schistosomes and their ability to produce eggs. We show that oxygen consumption rates (OCR) and egg production are significantly diminished by pharmacologic inhibition of carnitine palmitoyl transferase 1 (CPT1), which catalyzes a rate limiting step in fatty acid ?-oxidation (FAO) and by genetic loss of function of acyl CoA synthetase, which complexes with CPT1 and activates long chain FA for use in FAO, and of acyl CoA dehydrogenase, which catalyzes the first step in FAO within mitochondria. Declines in OCR and egg production correlate with changes in a network of lipid droplets within cells in a specialized reproductive organ, the vitellarium. Our data point to the importance of regulated lipid stores and FAO for the compartmentalized process of egg production in schistosomes.

Huang, Stanley Ching-Cheng; Freitas, Tori C.; Amiel, Eyal; Everts, Bart; Pearce, Erika L.; Lok, James B.; Pearce, Edward J.

2012-01-01

311

Natural Products Version 2.0: Connecting Genes to Molecules  

PubMed Central

Natural products have played a prominent role in the history of organic chemistry, and they continue to be important as drugs, biological probes, and targets of study for synthetic and analytical chemists. In this perspective, we explore how connecting Nature’s small molecules to the genes that encode them has sparked a renaissance in natural product research, focusing primarily on the biosynthesis of polyketides and nonribosomal peptides. We survey monomer biogenesis, coupling chemistries from templated and non-templated pathways, and the broad set of tailoring reactions and hybrid pathways that give rise to the diverse scaffolds and functionalization patterns of natural products. We conclude by considering two questions: What would it take to find all natural product scaffolds? What kind of scientists will be studying natural products in the future?

Walsh, Christopher T.; Fischbach, Michael A.

2009-01-01

312

Choice of oils for essential fat supplements can enhance production of abnormal metabolites in fat oxidation disorders.  

PubMed

Patients with mitochondrial long-chain fat oxidation deficiencies are usually treated with diets containing reduced fat and increased carbohydrate, at times via gastrostomy feeding. To ensure adequate intake of essential fatty acids, supplements are provided to their diets using commercially available oils. These oils contain large quantities of non-essential fats that are preferentially oxidized and produce disease-specific metabolites (acyl-CoA intermediates) due to the genetic defect. This study describes the concentrations of these intermediates as reflected by acylcarnitines as well as the % contribution from each of four fatty acids: palmitate, oleate, linoleate, and alpha-linolenate when incubated with fibroblasts from patients with VLCAD, LCHAD, and trifunctional protein (TFP) deficiencies. Palmitate and oleate produce the majority of disease-specific acylcarnitines with these defective cell lines (79-94%) whereas linoleate and linolenate produced less (6-21%). On average, the amount of acylcarnitines decreased with increasing unsaturation (C18:1>C18:2>C18:3:34%>11%>3%, respectively. This relationship may reflect the "gatekeeper" role of carnitine palmitoyltransferase I (CPT I). A diet comparison between Canola and a combination of Flax/Walnut oils revealed that the latter, containing the least amount of non-essential fats, reduced blood acylcarnitine levels by 33-36%. The etiology of the severe peripheral neuropathy of TFP deficiency may result from the unique metabolite, 3-keto-acyl-CoA, after conversion to a methylketone via spontaneous decarboxylation. Essential fatty acid supplementation with oils should consider these findings to decrease production of disease-specific acyl-CoA intermediates. PMID:17825594

Roe, Charles R; Roe, Diane S; Wallace, Mary; Garritson, Brenda

2007-12-01

313

The Type IV Fimbrial Subunit Gene (fimA) of Dichelobacter nodosus Is Essential for Virulence, Protease Secretion, and Natural Competence  

Microsoft Academic Search

Dichelobacter nodosus is the essential causative agent of footrot in sheep. The major D. nodosus-encoded viru- lence factors that have been implicated in the disease are type IV fimbriae and extracellular proteases. To ex- amine the role of the fimbriae in virulence, allelic exchange was used to insertionally inactivate the fimA gene, which encodes the fimbrial subunit protein, from the

RUTH M. KENNAN; OM P. DHUNGYEL; RICHARD J. WHITTINGTON; JOHN R. EGERTON; JULIAN I. ROOD

2001-01-01

314

CCN2 (Connective Tissue Growth Factor) is essential for extracellular matrix production and integrin signaling in chondrocytes  

PubMed Central

The matricellular protein CCN2 (Connective Tissue Growth Factor; CTGF) is an essential mediator of ECM composition, as revealed through analysis of Ccn2 deficient mice. These die at birth due to complications arising from impaired endochondral ossification. However, the mechanism(s) by which CCN2 mediates its effects in cartilage are unclear. We investigated these mechanisms using Ccn2?/? chondrocytes. Expression of type II collagen and aggrecan were decreased in Ccn2?/? chondrocytes, confirming a defect in ECM production. Ccn2?/? chondrocytes also exhibited impaired DNA synthesis and reduced adhesion to fibronectin. This latter defect is associated with decreased expression of ?5 integrin. Moreover, CCN2 can bind to integrin ?5?1 in chondrocytes and can stimulate increased expression of integrin ?5. Consistent with an essential role for CCN2 as a ligand for integrins, immunofluorescence and Western blot analysis revealed that levels of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK)1/2 phosphorylation were reduced in Ccn2?/? chondrocytes. These findings argue that CCN2 exerts major effects in chondrocytes through its ability to (1) regulate ECM production and integrin ?5 expression, (2) engage integrins and (3) activate integrin-mediated signaling pathways.

Nishida, Takashi; Kawaki, Harumi; Baxter, Ruth M.; DeYoung, R. Andrea; Takigawa, Masaharu

2007-01-01

315

The rpoN gene product of Pseudomonas aeruginosa is required for expression of diverse genes, including the flagellin gene.  

PubMed Central

The product of the rpoN gene is an alternative sigma factor of RNA polymerase which is required for transcription of a number of genes in members of the family Enterobacteriaceae, including those that specify enzymes of nitrogen assimilation, amino acid uptake, and degradation of a variety of organic molecules. We have previously shown that transcription of the pilin gene of Pseudomonas aeruginosa also requires RpoN (K. S. Ishimoto and S. Lory, Proc. Natl. Acad. Sci. USA 86:1954-1957, 1989) and have undertaken a more extensive survey of genes under RpoN control. Strains of P. aeruginosa that carry an insertionally inactivated rpoN gene were constructed and shown to be nonmotile because of the inability of these mutants to synthesize flagellin. The mutation in rpoN had no effect on expression of extracellular polypeptides, outer membrane proteins, and the alginate capsule. However, the rpoN mutants were glutamine auxotrophs and were defective in glutamine synthetase, indicating defects in nitrogen assimilation. In addition, the P. aeruginosa rpoN mutants were defective in urease activity. These findings indicate that the sigma factor encoded by the rpoN gene is used by P. aeruginosa for transcription of a diverse set of genes that specify biosynthetic enzymes, degradative enzymes, and surface components. These rpoN-controlled genes include pili and flagella which are required for full virulence of the organism. Images FIG. 1 FIG. 2

Totten, P A; Lara, J C; Lory, S

1990-01-01

316

Inositol monophosphatase activity from the Escherichia coli suhB gene product.  

PubMed Central

The suhB gene is located at 55 min on the Escherichia coli chromosome and encodes a protein of 268 amino acids. Mutant alleles of suhB have been isolated as extragenic suppressors for the protein secretion mutation (secY24), the heat shock response mutation (rpoH15), and the DNA synthesis mutation (dnaB121) (K. Shiba, K. Ito, and T. Yura, J. Bacteriol. 160:696-701, 1984; R. Yano, H. Nagai, K. Shiba, and T. Yura, J. Bacteriol. 172:2124-2130, 1990; S. Chang, D. Ng, L. Baird, and C. Georgopoulos, J. Biol. Chem. 266:3654-3660, 1991). These mutant alleles of suhB cause cold-sensitive cell growth, indicating that the suhB gene is essential at low temperatures. Little work has been done, however, to elucidate the role of the product of suhB in a normal cell and the suppression mechanisms of the suhB mutations in the aforementioned mutants. The sequence similarity shared between the suhB gene product and mammalian inositol monophosphatase has prompted us to test the inositol monophosphatase activity of the suhB gene product. We report here that the purified SuhB protein showed inositol monophosphatase activity. The kinetic parameters of SuhB inositol monophosphatase (Km = 0.071 mM; Vmax = 12.3 mumol/min per mg) are similar to those of mammalian inositol monophosphatase. The ssyA3 and suhB2 mutations, which were isolated as extragenic suppressors for secY24 and rpoH15, respectively, had a DNA insertion at the 5' proximal region of the suhB gene, and the amount of SuhB protein within mutant cells decreased. The possible role of suhB in E. coli is discussed.

Matsuhisa, A; Suzuki, N; Noda, T; Shiba, K

1995-01-01

317

Genome-Wide High-Throughput Screening to Investigate Essential Genes Involved in Methicillin-Resistant Staphylococcus aureus Sequence Type 398 Survival  

PubMed Central

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) Sequence Type 398 (ST398) is an opportunistic pathogen that is able to colonize and cause disease in several animal species including humans. To better understand the adaptation, evolution, transmission and pathogenic capacity, further investigations into the importance of the different genes harboured by LA-MRSA ST398 are required. In this study we generated a genome-wide transposon mutant library in an LA-MRSA ST398 isolate to evaluate genes important for bacterial survival in laboratory and host-specific environments. The transposon mutant library consisted of approximately 1 million mutants with around 140,000 unique insertion sites and an average number of unique inserts per gene of 44.8. We identified LA-MRSA ST398 essential genes comparable to other high-throughput S. aureus essential gene studies. As ST398 is the most common MRSA isolated from pigs, the transposon mutant library was screened in whole porcine blood. Twenty-four genes were specifically identified as important for bacterial survival in porcine blood. Mutations in 23 of these genes resulted in attenuated bacterial fitness. Seven of the 23 genes were of unknown function, whereas 16 genes were annotated with functions predominantly related to carbon metabolism, pH shock and a variety of regulations and only indirectly to virulence factors. Mutations in one gene of unknown function resulted in a hypercompetitive mutant. Further evaluation of these genes is required to determine their specific relevance in blood survival.

Christiansen, Mette T.; Kaas, Rolf S.; Chaudhuri, Roy R.; Holmes, Mark A.; Hasman, Henrik; Aarestrup, Frank M.

2014-01-01

318

Chemical composition of fennel essential oil and its impact on Staphylococcus aureus exotoxin production.  

PubMed

In this study, fennel oil was isolated by hydrodistillation, and the chemical composition was determined by gas chromatography/mass spectral analysis. The antimicrobial activity of fennel oil against Staphylococcus aureus was evaluated by broth microdilution. A haemolysis assay, tumour necrosis factor (TNF) release assay, western blot, and real-time reverse transcription (RT)-PCR were applied to investigate the influence of fennel oil on the production of S. aureus virulence-related exoproteins. The data show that fennel oil, which contains a high level of trans-anethole, was active against S. aureus, with MICs ranging from 64 to 256 ?g/ml. Furthermore, fennel oil, when used at subinhibitory concentrations, could dose-dependently decrease the expression of S. aureus exotoxins, including ?-toxin, Staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin 1 (TSST-1). PMID:22805920

Qiu, Jiazhang; Li, Hongen; Su, Hongwei; Dong, Jing; Luo, Mingjing; Wang, Jianfeng; Leng, Bingfeng; Deng, Yanhong; Liu, Juxiong; Deng, Xuming

2012-04-01

319

Natural product proteomining, a quantitative proteomics platform, allows rapid discovery of biosynthetic gene clusters for different classes of natural products.  

PubMed

Information on gene clusters for natural product biosynthesis is accumulating rapidly because of the current boom of available genome sequencing data. However, linking a natural product to a specific gene cluster remains challenging. Here, we present a widely applicable strategy for the identification of gene clusters for specific natural products, which we name natural product proteomining. The method is based on using fluctuating growth conditions that ensure differential biosynthesis of the bioactivity of interest. Subsequent combination of metabolomics and quantitative proteomics establishes correlations between abundance of natural products and concomitant changes in the protein pool, which allows identification of the relevant biosynthetic gene cluster. We used this approach to elucidate gene clusters for different natural products in Bacillus and Streptomyces, including a novel juglomycin-type antibiotic. Natural product proteomining does not require prior knowledge of the gene cluster or secondary metabolite and therefore represents a general strategy for identification of all types of gene clusters. PMID:24816229

Gubbens, Jacob; Zhu, Hua; Girard, Geneviève; Song, Lijiang; Florea, Bogdan I; Aston, Philip; Ichinose, Koji; Filippov, Dmitri V; Choi, Young H; Overkleeft, Herman S; Challis, Gregory L; van Wezel, Gilles P

2014-06-19

320

Analysis of the Essential Cell Division Gene ftsL of Bacillus subtilis by Mutagenesis and Heterologous Complementation  

PubMed Central

The ftsL gene is required for the initiation of cell division in a broad range of bacteria. Bacillus subtilis ftsL encodes a 13-kDa protein with a membrane-spanning domain near its N terminus. The external C-terminal domain has features of an ?-helical leucine zipper, which is likely to be involved in the heterodimerization with another division protein, DivIC. To determine what residues are important for FtsL function, we used both random and site-directed mutagenesis. Unexpectedly, all chemically induced mutations fell into two clear classes, those either weakening the ribosome-binding site or producing a stop codon. It appears that the random mutagenesis was efficient, so many missense mutations must have been generated but with no phenotypic effect. Substitutions affecting hydrophobic residues in the putative coiled-coil domain, introduced by site-directed mutagenesis, also gave no observable phenotype except for insertion of a helix-breaking proline residue, which destroyed FtsL function. ftsL homologues cloned from three diverse Bacillus species, Bacillus licheniformis, Bacillus badius, and Bacillus circulans, could complement an ftsL null mutation in B. subtilis, even though up to 66% of the amino acid residues of the predicted proteins were different from B. subtilis FtsL. However, the ftsL gene from Staphylococcus aureus (whose product has 73% of its amino acids different from those of the B. subtilis ftsL product) was not functional. We conclude that FtsL is a highly malleable protein that can accommodate a large number of sequence changes without loss of function.

Sievers, Jorg; Errington, Jeff

2000-01-01

321

Immunocytochemical Localization of the Cystic Fibrosis Gene Product CFTR  

Microsoft Academic Search

Antisera against two peptides, corresponding to different domains of the cystic fibrosis gene product CFTR, have been raised and extensively characterized. Both antisera recognize CFTR as a 165-kDa polypeptide in Western analysis of cells transfected with CFTR cDNA as well as in epithelial cell lines. The cell and tissue distribution of CFTR has been studied by immunocytochemistry. CFTR is abundant

Isabelle Crawford; Peter C. Maloney; Pamela L. Zeitlin; William B. Guggino; Stephen C. Hyde; Helen Turley; Kevin C. Gatter; Ann Harris; Christopher F. Higgins

1991-01-01

322

The Leishmania nicotinamidase is essential for NAD+ production and parasite proliferation.  

PubMed

NAD+ is a central cofactor that plays important roles in cellular metabolism and energy production in all living cells. Genomics-based reconstruction of NAD+ metabolism revealed that Leishmania protozoan parasites are NAD+ auxotrophs. Consequently, these parasites require assimilating NAD+ precursors (nicotinamide, nicotinic acid, nicotinamide riboside) from their host environment to synthesize NAD+ by a salvage pathway. Nicotinamidase is a key enzyme of this salvage pathway that catalyses conversion of nicotinamide (NAm) to nicotinic acid (Na), and that is absent in higher eukaryotes. We present here the biochemical and functional characterizations of the Leishmania infantum nicotinamidase (LiPNC1). Generation of Lipnc1 null mutants leads to a decrease in NAD+ content, associated with a metabolic shutdown-like phenotype with an extensive lag phase of growth. Both phenotypes could be rescued by an add-back construct or by addition of exogenous Na. In addition, Lipnc1 null mutants were unable to establish a sustained infection in a murine experimental model. Altogether, these results illustrate that NAD+ homeostasis is a fundamental component of Leishmania biology and virulence, and that NAm constitutes its main NAD+ source in the mammalian host. The crystal structure of LiPNC1 we solved allows now the design of rational inhibitors against this new promising therapeutic target. PMID:21819459

Gazanion, E; Garcia, D; Silvestre, R; Gérard, C; Guichou, J F; Labesse, G; Seveno, M; Cordeiro-Da-Silva, A; Ouaissi, A; Sereno, D; Vergnes, B

2011-10-01

323

Post transcriptional regulation of chloroplast gene expression by nuclear encoded gene products  

SciTech Connect

The following is a review of research accomplished in the first two years of funding for the above mentioned project. The work performed is a molecular characterization of nuclear mutants of Chlamydomonas reinhardtii which are deficient in different stages in the post-transcriptional expression of a single chloroplast encoded polypeptide, the D2 protein of Photosystem II. Our long-term goals are to understand the molecular mechanisms by which nuclear gene products affect the expression of chloroplast genes. Specifically, we which to understand how specific nuclear gene products affect the turnover rate of the D2 encoding mRNA (psbD), how other nuclear encoded factors work to promote the translation of psbD mRNA and/or stabilize the D2 protein, and what the role of the D2 protein itself is in Photosystem II assembly and in the control of expression of other chloroplast genes. This progress report will be organized into four major sections concerning (I) The characterization of nuclear mutants affected in D2 translation/turnover, (II) The study of trans-acting factors which associate with the 5{prime} end of the psbD mRNA, (III) In vitro mutagenesis of the psbD gene, and (IV) Additional studies.

Kuchka, M.R.

1992-01-01

324

The human cytomegalovirus US27 gene product enhances cell proliferation and alters cellular gene expression.  

PubMed

Human cytomegalovirus (HCMV) is a prevalent pathogen worldwide. Although generally harmless in healthy individuals, HCMV can pose a serious threat to immune compromised individuals and developing fetuses in utero. HCMV encodes four genes predicted to give rise to G protein-coupled receptors (GPCRs): US27, US28, UL33, and UL78. The US28 gene product is a functional chemokine receptor that enhances cell growth in some cell types but induces apoptosis in others. In contrast, the US27 gene product has not been demonstrated to signal either constitutively or in a ligand-induced manner. In this study, US27 was expressed in transfected cells, and both cell proliferation and DNA synthesis were significantly increased compared to control cells. PCR array analysis revealed that expression of US27 led to changes in a limited number of cellular genes, but genes that were up-regulated included the pro-survival factor Bcl-x, AP-1 transcription factor components jun and fos, and the IL-6 family cytokine oncostatin M. These results demonstrate that US27 can impact host cell physiology and may shed light on the function of this orphan viral GPCR. PMID:23850869

Lares, Angela P; Tu, Carolyn C; Spencer, Juliet V

2013-09-01

325

Use of a riboswitch-controlled conditional hypomorphic mutation to uncover a role for the essential csrA gene in bacterial autoaggregation.  

PubMed

Essential genes encode biological functions critical for cell survival. Correspondingly, their null mutants are often difficult to obtain, which impedes subsequent genetic and functional analysis. Here, we describe the development and utility of a theophylline-responsive riboswitch that enables target gene expression to be specifically "tuned" from low to high levels, which may be used to generate conditional hypomorphic mutants. Low levels of gene activity in the absence of the ligand (theophylline) permit cell survival, enabling gene activities to be investigated. Normal gene expression levels and wild-type phenotypes can be restored by the addition of the ligand. We demonstrate the utility of this approach with csrA, an essential gene in Escherichia coli that encodes the global regulatory protein CsrA. We placed the theophylline-responsive riboswitch immediately upstream of the csrA ribosome binding site, with the resulting mutant named switch-csrA. Hypomorphism of switch-csrA and its specific responsiveness to theophylline were verified by phenotypic examination and translation analysis. The utility of switch-csrA revealed a previously unidentified function for CsrA, namely its role as a repressor of cellular autoaggregation. Specifically, switch-csrA in the non-ligand-bound form produced low levels of CsrA, and its cells autoaggregated. Theophylline binding induced conformational changes in the riboswitch and permitted efficient csrA translation; consequently, autoaggregation did not occur. Our results indicate that CsrA modulates autoaggregation via the polysaccharide adhesin poly-beta-1,6-N-acetyl-D-glucosamine. In summary, the use of ligand-responsive riboswitches to construct conditional hypomorphic mutants represents a novel approach for investigating the activities of essential genes, which effectively complements traditional genetic approaches. PMID:19706608

Jin, Ye; Watt, Rory M; Danchin, Antoine; Huang, Jian-dong

2009-10-16

326

Characterization of lipase-deficient mutants of Acinetobacter calcoaceticus BD413: identification of a periplasmic lipase chaperone essential for the production of extracellular lipase.  

PubMed Central

Acinetobacter calcoaceticus BD413 produces an extracellular lipase, which is encoded by the lipA gene. Five lipase-deficient mutants have been generated via random insertion mutagenesis. Phenotypic characterization of these mutants revealed the presence of as many as four lipolytic enzymes in A. calcoaceticus. Biochemical evidence classified four of the mutants as export mutants, which presumably are defective in translocation of the lipase across the outer membrane. The additional mutant, designated AAC302, displays a LipA- phenotype, and yet the mutation in this strain was localized 0.84 kbp upstream of lipA. Sequence analysis of this region revealed an open reading frame, designated lipB, that is disrupted in AAC302. The protein encoded by this open reading frame shows extensive similarity to a chaperone-like helper protein of several pseudomonads, required for the production of extracellular lipase. Via complementation of AAC302 with a functional extrachromosomal copy of lipA, it could be determined that LipB is essential for lipase production. As shown by the use of a translational LipB-PhoA fusion construct, the C-terminal part of LipB of A. calcoaceticus BD413 is located outside the cytoplasm. Sequence analysis further strongly suggests that A. calcoaceticus LipB is N terminally anchored in the cytoplasmic membrane. Therefore, analogous to the situation in Pseudomonas species, however, lipB in A. calcoaceticus is located upstream of the structural lipase gene. lipB and lipA form a bicistronic operon, and the two genes are cotranscribed from an Escherichia coli sigma 70-type promoter. The reversed order of genes, in comparison with the situation in Pseudomonas species, suggests that LipA and LipB are produced in equimolar amounts. Therefore, the helper protein presumably does not only have a catalytic function, e.g., in folding of the lipase, but is also likely to act as a lipase-specific chaperone. A detailed model of the export route of the lipase of A. calcoaceticus BD413 is proposed.

Kok, R G; van Thor, J J; Nugteren-Roodzant, I M; Vosman, B; Hellingwerf, K J

1995-01-01

327

Antifungal activity and inhibition of fumonisin production by Rosmarinus officinalis L. essential oil in Fusarium verticillioides (Sacc.) Nirenberg.  

PubMed

The chemical composition of Rosmarinus officinalis L. essential oil (REO) was analysed by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The main compounds of the REO were 1.8 cineole (52.2%), camphor (15.2%) and ?-pinene (12.4%). The mycelial growth of Fusarium verticillioides (Sacc.) Nirenberg was reduced significantly by 150?g/mL of REO. Significant microscopic morphological changes were visualised, such as the rupture of the cell wall and the leakage of cytoplasm at 300?g/mL of REO. At lower concentrations of REO, the effects on the production of ergosterol and the biomass of mycelium varied, as did the effects on the production of fumonisins, but at ?300?g/mL of REO, these processes were significantly inhibited, showing the effectiveness of the REO as an antifungal agent. The results suggested that the REO acts against F. verticillioides by disrupting the cell wall and causing the loss of cellular components, subsequently inhibiting the production of fumonisins and ergosterol. PMID:25053064

da Silva Bomfim, Natalia; Nakassugi, Lydiana Polis; Faggion Pinheiro Oliveira, Jessica; Kohiyama, Cassia Yumie; Mossini, Simone Aparecida Galerani; Grespan, Renata; Nerilo, Samuel Botião; Mallmann, Carlos Augusto; Alves Abreu Filho, Benicio; Machinski, Miguel

2015-01-01

328

The Hansenula polymorpha PER1 Gene Is Essential for Peroxisome Biogenesis and Encodes a Peroxisomal Matrix Protein with Both Carboxy and Amino-terminal Targeting Signals  

Microsoft Academic Search

We describe the cloning of the Hansenula polymorpha PER1 gene and the characterization of the gene and its product, PER1p. The gene was cloned by functional complementation of a per1 mutant of H. polymorpha, which was impaired in the import of peroxisomal matrix proteins (Pim- phenotype). The DNA sequence of PER1 predicts that PER1p is a polypeptide of 650 amino

Hans R. Waterham; Vladimir I. Titorenko; Peter Haima; James M. Cregg; Wim Harder; Marten Veenhuis

1994-01-01

329

Stabilization of emulsion and butter like products containing essential fatty acids using kalonji seeds extract and curcuminoids.  

PubMed

Owing to the tendency of essential fatty acids (EFAs) to undergo autoxidation, their storage becomes a key problem. Generally, they are stabilized by synthetic antioxidants like TBHQ that are toxic in nature. Recently many studies were reported where these EFAs are stabilized by natural antioxidants. In the present study, curcuminoids and kalonji seeds ethanol extract (KEE) were used to stabilize these EFAs in refined sunflower oil (RSFO), water-in-oil (w/o) emulsion and butter like products (BLPs). In RSFO, though curcuminoids alone exerted pro-oxidant effect, KEE and curcuminoids showed synergistic antioxidant activity that was comparable to TBHQ. KEE exhibited good antioxidant activity in emulsions and BLPs, providing fine physical properties like slipping point, dropping point and spreadability. EFAs increased the nutritional value of BLPs and antioxidants added for their stabilization provided their medicinal benefits. PMID:22188801

Rege, Sameera A; Momin, Shamim A; Bhowmick, Dipti N; Pratap, Amit A

2012-01-01

330

Viral gene delivery: optimized protocol for production of high titer lentiviral vectors.  

PubMed

HIV-derived lentiviral vectors (LVV) are among the most commonly used gene delivery vehicles. Their production in high quantities, which enables concentration of viral particles to high titers, is important for their successful application in both biomedical research and gene therapy. LVV are produced by co-transfection of three or more plasmids into a packaging cell line followed by several purification and concentration steps. Protocols currently in circulation differ from each other but the direct comparison of their efficacy based on the published information is extremely difficult because more than one variable may be changed and essential information may be omitted. We systematically evaluated three protocols and found that one single modification described here, using FuGene(®) 6 in the co-transfection step, increase LVV output almost 20 times as compared to the most commonly used calcium phosphate (CaPO4) transfection technique. Unexpectedly FuGene(®) 6 was also much more efficient than another widely used reagent, Superfect. Dependent on requirements, this permits a dramatic downscaling of the packaging stage of viral production, and/or super-concentration of LVV to achieve stronger expression. For example we were able to prepare ?25 ?L of high titer LVV suitable for injections into rodent brain using a single T75 cm(2) cell culture flask of packaging cells. The same output would require up to 20 times more packaging cells and reagents following conventional protocols. We illustrate the potential of our approach using transfection of primary neuronal cultures with LVV expressing an optogenetic actuator channelrhodopsin-2. Our observations should help to achieve reproducible production of high titer LVV for experimental and potential therapeutic applications. PMID:23529421

Hewinson, James; Paton, Julian F R; Kasparov, Sergey

2013-01-01

331

The Streptomyces venezuelae pikAV gene contains a transcription unit essential for expression of enzymes involved in glycosylation of narbonolide and 10-deoxymethynolide  

Microsoft Academic Search

In Streptomyces venezuelae, four polyketide synthase (PKS) polypeptides encoded by pikAI-pikAIV are used to generate 10 and 12-membered macrocyclic structures, narbonolide and 10-deoxymethynolide. Sequence analysis suggests these genes are translationally coupled with downstream genes, pikAV (encoding a type II thioesterase), desVIII-desVI (encoding enzymes responsible for production of the final glycosylated products pikromycin, narbomycin, methymycin and neomethymycin) and desR (a resistance

Shuo Chen; Jeffrey B. Roberts; Yongquan Xue; David H. Sherman; Kevin A. Reynolds

2001-01-01

332

Inhibition of aflatoxin production and growth of Aspergillus parasiticus by Cuminum cyminum, Ziziphora clinopodioides, and Nigella sativa essential oils.  

PubMed

Aflatoxins are highly toxic and carcinogenic metabolites produced by Aspergillus parasiticus on food and agricultural commodities. Natural products may control the production of aflatoxins. The aims of this study were to evaluate the effects of the essential oils (EOs) of Cuminum cyminum, Ziziphora clinopodioides, and Nigella sativa on growth and aflatoxins production by A. parasiticus. Minimal inhibitory concentrations (MICs) and minimal fungicidal concentrations (MFCs) of the EOs were determined and compared with each other. Determination of aflatoxins (AFB(1), AFB(2), AFG(1), and AFG(2)) was performed by immunoaffinity column extraction using reverse phase-high performance liquid chromatography. The major oil components were ?-pinene (30%) in C. cyminum, pulegone (37%) in Z. clinopodioides, and trans-anthol (38.9%) in N. sativa oils. In broth microdilution method, C. cyminum oil exhibited the strongest activity (MIC(90): 1.6; MFC: 3.5?mg/mL), followed by Z. clinopodioides (MIC(90): 2.1; MFC: 5.5?mg/mL) and N. sativa (MIC(90): 2.75; MFC: 6.25?mg/mL) oils against A. parasiticus (p<0.05). Aflatoxin production was inhibited at 0.25?mg/mL of C. cyminum and Z. clinopodioides oils, of which that of C. cyminum was a stronger inhibitor. C. cyminum EO caused significant reductions in values of 94.2% for AFB(1), 100% for AFB(2), 98.9% for AFG(1), 100% for AFG(2), and 97.5% for total aflatoxin. It is concluded that the EOs of C. cyminum, Z. clinopodioides, and N. sativa could be used as natural inhibitors in foods at low concentrations to protect from fungal and toxin contaminations by A. parasiticus. PMID:21861703

Khosravi, Ali Reza; Shokri, Hojjatollah; Minooeianhaghighi, Mohammadhassan

2011-12-01

333

Involvement of distinct PKC gene products in T cell functions  

PubMed Central

It is well established that members of the protein kinase C (PKC) family seem to have important roles in T cells. Focusing on the physiological and non-redundant PKC functions established in primary mouse T cells via germline gene-targeting approaches, our current knowledge defines two particularly critical PKC gene products, PKC? and PKC?, as the “flavor of PKC” in T cells that appear to have a positive role in signaling pathways that are necessary for full antigen receptor-mediated T cell activation ex vivo and T cell-mediated immunity in vivo. Consistently, in spite of the current dogma that PKC? inhibition might be sufficient to achieve complete immunosuppressive effects, more recent results have indicated that the pharmacological inhibition of PKC?, and additionally, at least PKC?, appears to be needed to provide a successful approach for the prevention of allograft rejection and treatment of autoimmune diseases.

Pfeifhofer-Obermair, Christa; Thuille, Nikolaus; Baier, Gottfried

2012-01-01

334

Manipulating the regulatory genes for teicoplanin production in Actinoplanes teichomyceticus.  

PubMed

Actinoplanes teichomyceticus produces the lipoglycopeptide antibiotic teicoplanin, which is considered a last line of defense against multidrug resistant Gram-positive cocci. Different strategies have been employed to generate industrial producers of teicoplanin, however they do not include manipulations of teicoplanin biosynthetic genes due to a poorly developed genetic "toolkit" for this strain. Through this work, we extend the choice of vectors that can be conjugally transferred and maintained in A. teichomyceticus. Antibiotic producing properties and stability of the transconjugants have been examined. As an illustration of the utility of pSG5-based vector pKC1139, we improved teicoplanin production by the wild type strain via manipulations of two regulatory genes from the teicoplanin biosynthetic cluster, tcp28 and tcp29. PMID:22806031

Horbal, Lilia; Zaburannyy, Nestor; Ostash, Bohdan; Shulga, Sergiy; Fedorenko, Victor

2012-05-01

335

A concerted action of a paired-type homeobox gene, aristaless, and a homolog of Hox11\\/tlx homeobox gene, clawless, is essential for the distal tip development of the Drosophila leg  

Microsoft Academic Search

The subdivision of the developing field by region-specific expression of genes encoding transcription factors is an essential step during appendage development in arthropod and vertebrates. In Drosophila leg development, the distal-most region (pretarsus) is specified by the expression of homeobox genes, aristaless and Lim1, and its immediate neighbor (distal tarsus) is specified by the expression of a pair of Bar

Tetsuya Kojima; Takuya Tsuji; Kaoru Saigo

2005-01-01

336

The Product of the Herpes Simplex Virus Type 1 UL25 Gene Is Required for Encapsidation but Not for Cleavage of Replicated Viral DNA  

Microsoft Academic Search

The herpes simplex virus type 1 (HSV-1) UL25 gene contains a 580-amino-acid open reading frame that codes for an essential protein. Previous studies have shown that the UL25 gene product is a virion component (M. A. Ali et al., Virology 216:278-283, 1996) involved in virus penetration and capsid assembly (C. Addison et al., Virology 138:246-259, 1984). In this study, we

ALISTAIR R. MCNAB; PRASHANT DESAI; STAN PERSON; LORI L. ROOF; DARRELL R. THOMSEN; WILLIAM W. NEWCOMB; JAY C. BROWN; FRED L. HOMA

1998-01-01

337

Lactobacillus reuteri-specific immunoregulatory gene rsiR modulates histamine production and immunomodulation by Lactobacillus reuteri.  

PubMed

Human microbiome-derived strains of Lactobacillus reuteri potently suppress proinflammatory cytokines like human tumor necrosis factor (TNF) by converting the amino acid l-histidine to the biogenic amine histamine. Histamine suppresses mitogen-activated protein (MAP) kinase activation and cytokine production by signaling via histamine receptor type 2 (H2) on myeloid cells. Investigations of the gene expression profiles of immunomodulatory L. reuteri ATCC PTA 6475 highlighted numerous genes that were highly expressed during the stationary phase of growth, when TNF suppression is most potent. One such gene was found to be a regulator of genes involved in histidine-histamine metabolism by this probiotic species. During the course of these studies, this gene was renamed the Lactobacillus reuteri-specific immunoregulatory (rsiR) gene. The rsiR gene is essential for human TNF suppression by L. reuteri and expression of the histidine decarboxylase (hdc) gene cluster on the L. reuteri chromosome. Inactivation of rsiR resulted in diminished TNF suppression in vitro and reduced anti-inflammatory effects in vivo in a trinitrobenzene sulfonic acid (TNBS)-induced mouse model of acute colitis. A L. reuteri strain lacking an intact rsiR gene was unable to suppress colitis and resulted in greater concentrations of serum amyloid A (SAA) in the bloodstream of affected animals. The PhdcAB promoter region targeted by rsiR was defined by reporter gene experiments. These studies support the presence of a regulatory gene, rsiR, which modulates the expression of a gene cluster known to mediate immunoregulation by probiotics at the transcriptional level. These findings may point the way toward new strategies for controlling gene expression in probiotics by dietary interventions or microbiome manipulation. PMID:24123819

Hemarajata, P; Gao, C; Pflughoeft, K J; Thomas, C M; Saulnier, D M; Spinler, J K; Versalovic, J

2013-12-01

338

Lactobacillus reuteri-Specific Immunoregulatory Gene rsiR Modulates Histamine Production and Immunomodulation by Lactobacillus reuteri  

PubMed Central

Human microbiome-derived strains of Lactobacillus reuteri potently suppress proinflammatory cytokines like human tumor necrosis factor (TNF) by converting the amino acid l-histidine to the biogenic amine histamine. Histamine suppresses mitogen-activated protein (MAP) kinase activation and cytokine production by signaling via histamine receptor type 2 (H2) on myeloid cells. Investigations of the gene expression profiles of immunomodulatory L. reuteri ATCC PTA 6475 highlighted numerous genes that were highly expressed during the stationary phase of growth, when TNF suppression is most potent. One such gene was found to be a regulator of genes involved in histidine-histamine metabolism by this probiotic species. During the course of these studies, this gene was renamed the Lactobacillus reuteri-specific immunoregulatory (rsiR) gene. The rsiR gene is essential for human TNF suppression by L. reuteri and expression of the histidine decarboxylase (hdc) gene cluster on the L. reuteri chromosome. Inactivation of rsiR resulted in diminished TNF suppression in vitro and reduced anti-inflammatory effects in vivo in a trinitrobenzene sulfonic acid (TNBS)-induced mouse model of acute colitis. A L. reuteri strain lacking an intact rsiR gene was unable to suppress colitis and resulted in greater concentrations of serum amyloid A (SAA) in the bloodstream of affected animals. The PhdcAB promoter region targeted by rsiR was defined by reporter gene experiments. These studies support the presence of a regulatory gene, rsiR, which modulates the expression of a gene cluster known to mediate immunoregulation by probiotics at the transcriptional level. These findings may point the way toward new strategies for controlling gene expression in probiotics by dietary interventions or microbiome manipulation.

Hemarajata, P.; Gao, C.; Pflughoeft, K. J.; Thomas, C. M.; Saulnier, D. M.; Spinler, J. K.

2013-01-01

339

dcp gene of Escherichia coli: cloning, sequencing, transcript mapping, and characterization of the gene product.  

PubMed Central

Dipeptidyl carboxypeptidase is a C-terminal exopeptidase of Escherichia coli. We have isolated the respective gene, dcp, from a low-copy-number plasmid library by its ability to complement a dcp mutation preventing the utilization of the unique substrate N-benzoyl-L-glycyl-L-histidyl-L-leucine. Sequence analysis of a 2.9-kb DNA fragment revealed an open reading frame of 2,043 nucleotides which was assigned to the dcp gene by N-terminal amino acid sequencing and electrophoretic molecular mass determination of the purified dcp product. Transcript mapping by primer extension and S1 protection experiments verified the physiological significance of potential initiation and termination signals for dcp transcription and allowed the identification of a single species of monocistronic dcp mRNA. The codon usage pattern and the effects of elevated gene copy number indicated a relatively low level of dcp expression. The predicted amino acid sequence of dipeptidyl carboxypeptidase, containing a potential zinc-binding site, is highly homologous (78.8%) to the corresponding enzyme from Salmonella typhimurium. It also displays significant homology to the products of the S. typhimurium opdA and the E. coli prlC genes and to some metalloproteases from rats and Saccharomyces cerevisiae. No potential export signals could be inferred from the amino acid sequence. Dipeptidyl carboxypeptidase was enriched 80-fold from crude extracts of E. coli and used to investigate some of its biochemical and biophysical properties. Images

Henrich, B; Becker, S; Schroeder, U; Plapp, R

1993-01-01

340

Myxococcus xanthus dif Genes Are Required for Biogenesis of Cell Surface Fibrils Essential for Social Gliding Motility  

PubMed Central

Myxococcus xanthus social (S) gliding motility has been previously reported by us to require the chemotaxis homologues encoded by the dif genes. In addition, two cell surface structures, type IV pili and extracellular matrix fibrils, are also critical to M. xanthus S motility. We have demonstrated here that M. xanthus dif genes are required for the biogenesis of fibrils but not for that of type IV pili. Furthermore, the developmental defects of dif mutants can be partially rescued by the addition of isolated fibril materials. Along with the chemotaxis genes of various swarming bacteria and the pilGHIJ genes of the twitching bacterium Pseudomonas aeruginosa, the M. xanthus dif genes belong to a unique class of bacterial chemotaxis genes or homologues implicated in the biogenesis of structures required for bacterial surface locomotion. Genetic studies indicate that the dif genes are linked to the M. xanthus dsp region, a locus known to be crucial for M. xanthus fibril biogenesis and S gliding.

Yang, Zhaomin; Ma, Xiaoyuan; Tong, Leming; Kaplan, Heidi B.; Shimkets, Lawrence J.; Shi, Wenyuan

2000-01-01

341

Molecular Cloning, Expression, and Characterization of the Genes Encoding the Two Essential Protein Components of Micrococcus luteus BP 26 Hexaprenyl Diphosphate Synthase  

Microsoft Academic Search

The structural genes encoding the two essential components A and B of hexaprenyl diphosphate synthase, which produce the precursor of the prenyl side chain of menaquinone-6, were cloned from Micrococcus luteus B-P 26. Hexaprenyl diphosphate synthase (EC 2.5.1.33) (HexPS) catalyzes condensation of three molecules of isopentenyl di- phosphate with farnesyl diphosphate (FPP) to afford (all-E)- hexaprenyl diphosphate (HexPP; C30), the

NAOTO SHIMIZU; TANETOSHI KOYAMA; KYOZO OGURA

1998-01-01

342

Essential Tremor  

MedlinePLUS

NINDS Essential Tremor Information Page Table of Contents (click to jump to sections) What is Essential Tremor? Is there any treatment? What is the prognosis? What research is being done? Clinical Trials Organizations What is Essential Tremor? Tremor ...

343

Engineering broad root-knot resistance in transgenic plants by RNAi silencing of a conserved and essential root-knot nematode parasitism gene  

PubMed Central

Secreted parasitism proteins encoded by parasitism genes expressed in esophageal gland cells mediate infection and parasitism of plants by root-knot nematodes (RKN). Parasitism gene 16D10 encodes a conserved RKN secretory peptide that stimulates root growth and functions as a ligand for a putative plant transcription factor. We used in vitro and in vivo RNA interference approaches to silence this parasitism gene in RKN and validate that the parasitism gene has an essential function in RKN parasitism of plants. Ingestion of 16D10 dsRNA in vitro silenced the target parasitism gene in RKN and resulted in reduced nematode infectivity. In vivo expression of 16D10 dsRNA in Arabidopsis resulted in resistance effective against the four major RKN species. Because no known natural resistance gene has this wide effective range of RKN resistance, bioengineering crops expressing dsRNA that silence target RKN parasitism genes to disrupt the parasitic process represents a viable and flexible means of developing novel durable RKN-resistant crops and could provide crops with unprecedented broad resistance to RKN.

Huang, Guozhong; Allen, Rex; Davis, Eric L.; Baum, Thomas J.; Hussey, Richard S.

2006-01-01

344

Identification of the essential and non-essential transcription units for protein synthesis, DNA replication and infectious virus production of Porcine circovirus type 1  

Microsoft Academic Search

Summary. A plasmid-based transfection system capable of yielding infectious Porcine circovirus type 1 (PCV1) was established and mutational analysis was conducted to investigate the involvement of each viral transcription unit in protein synthesis, DNA replication and progeny virus production. During PCV1 replication in PK15 cells, twelve viral-specific RNAs are synthesized. They include the capsid protein RNA ( CR), eight Rep-associated

A. K. Cheung

2004-01-01

345

Point mutations identify a conserved region of the saccharomyces cerevisiae AFR1 gene that is essential for both the pheromone signaling and morphogenesis functions.  

PubMed Central

Mating pheromone receptors activate a G protein signal pathway that leads to the conjugation of the yeast Saccharomyces cerevisiae. This pathway also induces the production of Afr1p, a protein that negatively regulates pheromone receptor signaling and is required to form pointed projections of new growth that become the site of cell fusion during mating. Afr1p lacks strong similarity to any well-characterized proteins to help predict how it acts. Therefore, we investigated the relationship between the different functions of Afr1p by isolating and characterizing seven mutants that were defective in regulating pheromone signaling. The AFR1 mutants were also defective when expressed as fusions to STE2, the alpha-factor receptor, indicating that the mutant Afr1 proteins are defective in function and not in co-localizing with receptors. The mutant genes contained four distinct point mutations that all occurred between codons 254 and 263, identifying a region that is critical for AFR1 function. Consistent with this, we found that the corresponding region is very highly conserved in the Afr1p homologs from the yeasts S. uvarum and S. douglasii. In contrast, there were no detectable effects on pheromone signaling caused by deletion or overexpression of YER158c, an open reading frame with overall sequence similarity to Afr1p that lacks this essential region. Interestingly, all of the AFR1 mutants showed a defect in their ability to form mating projections that was proportional to their defect in regulating pheromone signaling. This suggests that both functions may be due to the same action of Afr1p. Thus, these studies identify a specific region of Afr1p that is critical for its function in both signaling and morphogenesis.

DeMattei, C R; Davis, C P; Konopka, J B

2000-01-01

346

Reactivation of methionine synthase from Thermotoga maritima (TM0268) requires the downstream gene product TM0269.  

PubMed

The crystal structure of the Thermotoga maritima gene product TM0269, determined as part of genome-wide structural coverage of T. maritima by the Joint Center for Structural Genomics, revealed structural homology with the fourth module of the cobalamin-dependent methionine synthase (MetH) from Escherichia coli, despite the lack of significant sequence homology. The gene specifying TM0269 lies in close proximity to another gene, TM0268, which shows sequence homology with the first three modules of E. coli MetH. The fourth module of E. coli MetH is required for reductive remethylation of the cob(II)alamin form of the cofactor and binds the methyl donor for this reactivation, S-adenosylmethionine (AdoMet). Measurements of the rates of methionine formation in the presence and absence of TM0269 and AdoMet demonstrate that both TM0269 and AdoMet are required for reactivation of the inactive cob(II)alamin form of TM0268. These activity measurements confirm the structure-based assignment of the function of the TM0269 gene product. In the presence of TM0269, AdoMet, and reductants, the measured activity of T. maritima MetH is maximal near 80 degrees C, where the specific activity of the purified protein is approximately 15% of that of E. coli methionine synthase (MetH) at 37 degrees C. Comparisons of the structures and sequences of TM0269 and the reactivation domain of E. coli MetH suggest that AdoMet may be bound somewhat differently by the homologous proteins. However, the conformation of a hairpin that is critical for cobalamin binding in E. coli MetH, which constitutes an essential structural element, is retained in the T. maritima reactivation protein despite striking divergence of the sequences. PMID:17656578

Huang, Sha; Romanchuk, Gail; Pattridge, Katherine; Lesley, Scott A; Wilson, Ian A; Matthews, Rowena G; Ludwig, Martha

2007-08-01

347

Reactivation of methionine synthase from Thermotoga maritima (TM0268) requires the downstream gene product TM0269  

PubMed Central

The crystal structure of the Thermotoga maritima gene product TM0269, determined as part of genome-wide structural coverage of T. maritima by the Joint Center for Structural Genomics, revealed structural homology with the fourth module of the cobalamin-dependent methionine synthase (MetH) from Escherichia coli, despite the lack of significant sequence homology. The gene specifying TM0269 lies in close proximity to another gene, TM0268, which shows sequence homology with the first three modules of E. coli MetH. The fourth module of E. coli MetH is required for reductive remethylation of the cob(II)alamin form of the cofactor and binds the methyl donor for this reactivation, S-adenosylmethionine (AdoMet). Measurements of the rates of methionine formation in the presence and absence of TM0269 and AdoMet demonstrate that both TM0269 and AdoMet are required for reactivation of the inactive cob(II)alamin form of TM0268. These activity measurements confirm the structure-based assignment of the function of the TM0269 gene product. In the presence of TM0269, AdoMet, and reductants, the measured activity of T. maritima MetH is maximal near 80°C, where the specific activity of the purified protein is ?15% of that of E. coli methionine synthase (MetH) at 37°C. Comparisons of the structures and sequences of TM0269 and the reactivation domain of E. coli MetH suggest that AdoMet may be bound somewhat differently by the homologous proteins. However, the conformation of a hairpin that is critical for cobalamin binding in E. coli MetH, which constitutes an essential structural element, is retained in the T. maritima reactivation protein despite striking divergence of the sequences.

Huang, Sha; Romanchuk, Gail; Pattridge, Katherine; Lesley, Scott A.; Wilson, Ian A.; Matthews, Rowena G.; Ludwig, Martha

2007-01-01

348

Identification of simian immunodeficiency virus SIVMAC env gene products.  

PubMed

A monoclonal antibody recognizing an antigenic determinant on the env transmembrane protein, gp32 of simian immunodeficiency virus SIVMAC has been developed and designated SF8/5E11. The reactivity of this antibody was found to be type specific, since it did not cross-react with either SIVSMM or SIVMNe transmembrane proteins. The availability of both this antibody and the complete nucleotide sequence of SIVMAC allowed us to define the organization of the env gene products of this virus. Radiolabel sequencing of the amino termini of both gp160 and gp32 confirmed the positions of both cleavage sites predicted by alignment of the inferred amino acid sequences of the SIVMAC and human immunodeficiency virus type 1 env genes. The cleavage site between the signal peptide and the external env glycoprotein resides between the cysteine residue at position 21 and the threonine residue at position 22, starting from the first residue after the env gene initiator methionine. The env precursor polyprotein gp160 is cleaved between arginine 526 and glycine 527 to give rise to the external glycoprotein and the transmembrane of SIVMAC. PMID:2464704

Veronese, F D; Joseph, B; Copeland, T D; Oroszlan, S; Gallo, R C; Sarngadharan, M G

1989-03-01

349

Refined Characterization of the Expression and Stability of the SMN Gene Products  

PubMed Central

Spinal muscular atrophy (SMA) is characterized by degeneration of lower motor neurons and caused by mutations of the SMN1 gene. SMN1 is duplicated in a homologous gene called SMN2, which remains present in patients. SMN has an essential role in RNA metabolism, but its role in SMA pathogenesis remains unknown. Previous studies suggested that in neurons the protein lacking the C terminus (SMN?7), the major product of the SMN2 gene, had a dominant-negative effect. We generated antibodies specific to SMNFL or SMN?7. In transfected cells, the stability of the SMN?7 protein was regulated in a cell-dependent manner. Importantly, whatever the human tissues examined, SMN?7 protein was undetectable because of the instability of the protein, thus excluding a dominant effect of SMN?7 in SMA. A similar decreased level of SMNFL was observed in brain and spinal cord samples from human SMA, suggesting that SMNFL may have specific targets in motor neurons. Moreover, these data indicate that the vulnerability of motor neurons cannot simply be ascribed to the differential expression or a more dramatic reduction of SMNFL in spinal cord when compared with brain tissue. Improving the stability of SMN?7 protein might be envisaged as a new therapeutic strategy in SMA.

Vitte, Jeremie; Fassier, Coralie; Tiziano, Francesco D.; Dalard, Cecile; Soave, Sabrina; Roblot, Natacha; Brahe, Christine; Saugier-Veber, Pascale; Bonnefont, Jean Paul; Melki, Judith

2007-01-01

350

Immune-responsive gene 1 protein links metabolism to immunity by catalyzing itaconic acid production.  

PubMed

Immunoresponsive gene 1 (Irg1) is highly expressed in mammalian macrophages during inflammation, but its biological function has not yet been elucidated. Here, we identify Irg1 as the gene coding for an enzyme producing itaconic acid (also known as methylenesuccinic acid) through the decarboxylation of cis-aconitate, a tricarboxylic acid cycle intermediate. Using a gain-and-loss-of-function approach in both mouse and human immune cells, we found Irg1 expression levels correlating with the amounts of itaconic acid, a metabolite previously proposed to have an antimicrobial effect. We purified IRG1 protein and identified its cis-aconitate decarboxylating activity in an enzymatic assay. Itaconic acid is an organic compound that inhibits isocitrate lyase, the key enzyme of the glyoxylate shunt, a pathway essential for bacterial growth under specific conditions. Here we show that itaconic acid inhibits the growth of bacteria expressing isocitrate lyase, such as Salmonella enterica and Mycobacterium tuberculosis. Furthermore, Irg1 gene silencing in macrophages resulted in significantly decreased intracellular itaconic acid levels as well as significantly reduced antimicrobial activity during bacterial infections. Taken together, our results demonstrate that IRG1 links cellular metabolism with immune defense by catalyzing itaconic acid production. PMID:23610393

Michelucci, Alessandro; Cordes, Thekla; Ghelfi, Jenny; Pailot, Arnaud; Reiling, Norbert; Goldmann, Oliver; Binz, Tina; Wegner, André; Tallam, Aravind; Rausell, Antonio; Buttini, Manuel; Linster, Carole L; Medina, Eva; Balling, Rudi; Hiller, Karsten

2013-05-01

351

Circadian clock genes frequency and white collar-1 are not essential for entrainment to temperature cycles in Neurospora crassa  

PubMed Central

The fungus Neurospora crassa is a model system for investigating the mechanism of circadian rhythmicity, and the core of its circadian oscillator is thought to be a transcription/translation feedback loop involving the products of the frq (frequency), wc-1 (white-collar-1) and wc-2 (white-collar-2) genes. Several reports of rhythmicity in frq and wc null mutants have raised questions about how central the FRQ/WC loop is to the circadian system of Neurospora. Several research groups have attempted to answer this question by looking for entrainment of the conidiation banding rhythm in frq null mutants. Because the frq mutants are blind to light and cannot be entrained to light/dark cycles, these groups have used symmetric temperature cycles of equal-duration cool and warm phases to entrain the rhythm. Under these conditions, the direct effects of temperature on conidiation (masking effects) can compromise observations of the endogenous rhythm. I have reexamined this question by using short heat pulses to clearly separate masking from endogenous rhythms, and I have assayed entrainment in both frq and wc-1 null mutants. I found similar patterns of entrainment in the wild type and both mutant strains. Strong masking effects were found in the frq mutant but not in the wc-1 mutant. I conclude that a rapidly damping temperature-entrainable oscillator is present in the null mutants. A single temperature-entrainable oscillator may drive the conidiation rhythm in all strains, and additional properties such as light sensitivity and temperature compensation may be conferred by the intact FRQ/WC loop in the WT strain.

Lakin-Thomas, Patricia L.

2006-01-01

352

Functional annotation of human cytomegalovirus gene products: an update  

PubMed Central

Human cytomegalovirus is an opportunistic double-stranded DNA virus with one of the largest viral genomes known. The 235 kB genome is divided in a unique long (UL) and a unique short (US) region which are flanked by terminal and internal repeats. The expression of HCMV genes is highly complex and involves the production of protein coding transcripts, polyadenylated long non-coding RNAs, polyadenylated anti-sense transcripts and a variety of non-polyadenylated RNAs such as microRNAs. Although the function of many of these transcripts is unknown, they are suggested to play a direct or regulatory role in the delicately orchestrated processes that ensure HCMV replication and life-long persistence. This review focuses on annotating the complete viral genome based on three sources of information. First, previous reviews were used as a template for the functional keywords to ensure continuity; second, the Uniprot database was used to further enrich the functional database; and finally, the literature was manually curated for novel functions of HCMV gene products. Novel discoveries were discussed in light of the viral life cycle. This functional annotation highlights still poorly understood regions of the genome but more importantly it can give insight in functional clusters and/or may be helpful in the analysis of future transcriptomics and proteomics studies.

Van Damme, Ellen; Van Loock, Marnix

2014-01-01

353

Cross-Product Extensions of the Gene Ontology  

PubMed Central

The Gene Ontology (GO) consists of nearly 30,000 classes for describing the activities and locations of gene products. Manual maintenance of an ontology of this size is a considerable effort, and errors and inconsistencies inevitably arise. Reasoners can be used to assist with ontology development, automatically placing classes in a subsumption hierarchy based on their properties. However, the historic lack of computable definitions within the GO has prevented the user of these tools. In this paper we present preliminary results of an ongoing effort to normalize the GO by explicitly stating the definitions of compositional classes in a form that can be used by reasoners. These definitions are partitioned into mutually exclusive cross-product sets, many of which reference other OBO Foundry candidate ontologies for chemical entities, proteins, biological qualities and anatomical entities. Using these logical definitions we are gradually beginning to automate many aspects of ontology development, detecting errors and filling in missing relationships. These definitions also enhance the GO by weaving it into the fabric of a wider collection of interoperating ontologies, increasing opportunities for data integration and enhancing genomic analyses.

Mungall, Christopher J.; Bada, Michael; Berardini, Tanya Z.; Deegan, Jennifer; Ireland, Amelia; Harris, Midori A.; Hill, David P.; Lomax, Jane

2010-01-01

354

Methyl Salicylate Production and Jasmonate Signaling Are Not Essential for Systemic Acquired Resistance in Arabidopsis[W  

PubMed Central

Systemic acquired resistance (SAR) develops in response to local microbial leaf inoculation and renders the whole plant more resistant to subsequent pathogen infection. Accumulation of salicylic acid (SA) in noninfected plant parts is required for SAR, and methyl salicylate (MeSA) and jasmonate (JA) are proposed to have critical roles during SAR long-distance signaling from inoculated to distant leaves. Here, we address the significance of MeSA and JA during SAR development in Arabidopsis thaliana. MeSA production increases in leaves inoculated with the SAR-inducing bacterial pathogen Pseudomonas syringae; however, most MeSA is emitted into the atmosphere, and only small amounts are retained. We show that in several Arabidopsis defense mutants, the abilities to produce MeSA and to establish SAR do not coincide. T-DNA insertion lines defective in expression of a pathogen-responsive SA methyltransferase gene are completely devoid of induced MeSA production but increase systemic SA levels and develop SAR upon local P. syringae inoculation. Therefore, MeSA is dispensable for SAR in Arabidopsis, and SA accumulation in distant leaves appears to occur by de novo synthesis via isochorismate synthase. We show that MeSA production induced by P. syringae depends on the JA pathway but that JA biosynthesis or downstream signaling is not required for SAR. In compatible interactions, MeSA production depends on the P. syringae virulence factor coronatine, suggesting that the phytopathogen uses coronatine-mediated volatilization of MeSA from leaves to attenuate the SA-based defense pathway.

Attaran, Elham; Zeier, Tatiana E.; Griebel, Thomas; Zeier, Jurgen

2009-01-01

355

Transcriptional control and patterning of the pho-1 gene, an essential acid phosphatase expressed in the C. elegans intestine  

Microsoft Academic Search

We have previously described an acid phosphatase enzyme, PHO-1, present at the lumenal surface of all but the anterior six cells of the Caenorhabditis elegans intestine. In the present paper, we identify the pho-1 structural gene, which encodes a histidine acid phosphatase showing highest similarity to human prostatic acid phosphatase. The pho-1 5?-flanking DNA is capable of directing reporter gene

Tetsunari Fukushige; Barbara Goszczynski; Jie Yan; James D. McGhee

2005-01-01

356

The Podospora rmp1 gene implicated in nucleus-mitochondria cross-talk encodes an essential protein whose subcellular location is developmentally regulated.  

PubMed Central

It has been previously reported that, at the time of death, the Podospora anserina AS1-4 mutant strains accumulate specific deleted forms of the mitochondrial genome and that their life spans depend on two natural alleles (variants) of the rmp1 gene: AS1-4 rmp1-2 strains exhibit life spans strikingly longer than those of AS1-4 rmp1-1. Here, we show that rmp1 is an essential gene. In silico analyses of eight rmp1 natural alleles present in Podospora isolates and of the putative homologs of this orphan gene in other filamentous fungi suggest that rmp1 evolves rapidly. The RMP1 protein is localized in the mitochondrial and/or the cytosolic compartment, depending on cell type and developmental stage. Strains producing RMP1 without its mitochondrial targeting peptide are viable but exhibit vegetative and sexual defects.

Contamine, Veronique; Zickler, Denise; Picard, Marguerite

2004-01-01

357

Genetic subtraction profiling identifies genes essential for Arabidopsis reproduction and reveals interaction between the female gametophyte and the maternal sporophyte  

PubMed Central

Background The embryo sac contains the haploid maternal cell types necessary for double fertilization and subsequent seed development in plants. Large-scale identification of genes expressed in the embryo sac remains cumbersome because of its inherent microscopic and inaccessible nature. We used genetic subtraction and comparative profiling by microarray between the Arabidopsis thaliana wild-type and a sporophytic mutant lacking an embryo sac in order to identify embryo sac expressed genes in this model organism. The influences of the embryo sac on the surrounding sporophytic tissues were previously thought to be negligible or nonexistent; we investigated the extent of these interactions by transcriptome analysis. Results We identified 1,260 genes as embryo sac expressed by analyzing both our dataset and a recently reported dataset, obtained by a similar approach, using three statistical procedures. Spatial expression of nine genes (for instance a central cell expressed trithorax-like gene, an egg cell expressed gene encoding a kinase, and a synergid expressed gene encoding a permease) validated our approach. We analyzed mutants in five of the newly identified genes that exhibited developmental anomalies during reproductive development. A total of 527 genes were identified for their expression in ovules of mutants lacking an embryo sac, at levels that were twofold higher than in the wild type. Conclusion Identification of embryo sac expressed genes establishes a basis for the functional dissection of embryo sac development and function. Sporophytic gain of expression in mutants lacking an embryo sac suggests that a substantial portion of the sporophytic transcriptome involved in carpel and ovule development is, unexpectedly, under the indirect influence of the embryo sac.

Johnston, Amal J; Meier, Patrick; Gheyselinck, Jacqueline; Wuest, Samuel EJ; Federer, Michael; Schlagenhauf, Edith; Becker, Jorg D; Grossniklaus, Ueli

2007-01-01

358

Effects of Essential Oils on Methane Production and Fermentation by, and Abundance and Diversity of, Rumen Microbial Populations  

PubMed Central

Five essential oils (EOs), namely, clove oil (CLO), eucalyptus oil (EUO), garlic oil (GAO), origanum oil (ORO), and peppermint oil (PEO), were tested in vitro at 3 different doses (0.25, 0.50, and 1.0 g/liter) for their effect on methane production, fermentation, and select groups of ruminal microbes, including total bacteria, cellulolytic bacteria, archaea, and protozoa. All the EOs significantly reduced methane production with increasing doses, with reductions by 34.4%, 17.6%, 42.3%, 87%, and 25.7% for CLO, EUO, GAO, ORO, and PEO, respectively, at 1.0 g/liter compared with the control. However, apparent degradability of dry matter and neutral detergent fiber also decreased linearly with increasing doses by all EOs except GAO. The concentrations of total volatile fatty acids were not affected by GAO, EUO, or PEO but altered linearly and quadratically by CLO and ORO, respectively. All the EOs also differed in altering the molar proportions of acetate, propionate, and butyrate. As determined by quantitative real-time PCR, all the EOs decreased the abundance of archaea, protozoa, and major cellulolytic bacteria (i.e., Fibrobacter succinogenes, Ruminococcus flavefaciens, and R. albus) linearly with increasing EO doses. On the basis of denaturing gradient gel electrophoresis analysis, different EOs changed the composition of both archaeal and bacterial communities to different extents. The Shannon-Wiener diversity index (H?) was reduced for archaea by all EOs in a dose-dependent manner but increased for bacteria at low and medium doses (0.25 and 0.50 g/liter) for all EOs except ORO. Due to the adverse effects on feed digestion and fermentation at high doses, a single EO may not effectively and practically mitigate methane emission from ruminants unless used at low doses in combinations with other antimethanogenic compounds.

Patra, Amlan K.

2012-01-01

359

Effects of essential oils on methane production and fermentation by, and abundance and diversity of, rumen microbial populations.  

PubMed

Five essential oils (EOs), namely, clove oil (CLO), eucalyptus oil (EUO), garlic oil (GAO), origanum oil (ORO), and peppermint oil (PEO), were tested in vitro at 3 different doses (0.25, 0.50, and 1.0 g/liter) for their effect on methane production, fermentation, and select groups of ruminal microbes, including total bacteria, cellulolytic bacteria, archaea, and protozoa. All the EOs significantly reduced methane production with increasing doses, with reductions by 34.4%, 17.6%, 42.3%, 87%, and 25.7% for CLO, EUO, GAO, ORO, and PEO, respectively, at 1.0 g/liter compared with the control. However, apparent degradability of dry matter and neutral detergent fiber also decreased linearly with increasing doses by all EOs except GAO. The concentrations of total volatile fatty acids were not affected by GAO, EUO, or PEO but altered linearly and quadratically by CLO and ORO, respectively. All the EOs also differed in altering the molar proportions of acetate, propionate, and butyrate. As determined by quantitative real-time PCR, all the EOs decreased the abundance of archaea, protozoa, and major cellulolytic bacteria (i.e., Fibrobacter succinogenes, Ruminococcus flavefaciens, and R. albus) linearly with increasing EO doses. On the basis of denaturing gradient gel electrophoresis analysis, different EOs changed the composition of both archaeal and bacterial communities to different extents. The Shannon-Wiener diversity index (H') was reduced for archaea by all EOs in a dose-dependent manner but increased for bacteria at low and medium doses (0.25 and 0.50 g/liter) for all EOs except ORO. Due to the adverse effects on feed digestion and fermentation at high doses, a single EO may not effectively and practically mitigate methane emission from ruminants unless used at low doses in combinations with other antimethanogenic compounds. PMID:22492451

Patra, Amlan K; Yu, Zhongtang

2012-06-01

360

Jasmonate and ethylene dependent defence gene expression and suppression of fungal virulence factors: two essential mechanisms of Fusarium head blight resistance in wheat?  

PubMed Central

Background Fusarium head blight (FHB) caused by Fusarium species like F. graminearum is a devastating disease of wheat (Triticum aestivum) worldwide. Mycotoxins such as deoxynivalenol produced by the fungus affect plant and animal health, and cause significant reductions of grain yield and quality. Resistant varieties are the only effective way to control this disease, but the molecular events leading to FHB resistance are still poorly understood. Transcriptional profiling was conducted for the winter wheat cultivars Dream (moderately resistant) and Lynx (susceptible). The gene expressions at 32 and 72?h after inoculation with Fusarium were used to trace possible defence mechanisms and associated genes. A comparative qPCR was carried out for selected genes to analyse the respective expression patterns in the resistant cultivars Dream and Sumai 3 (Chinese spring wheat). Results Among 2,169 differentially expressed genes, two putative main defence mechanisms were found in the FHB-resistant Dream cultivar. Both are defined base on their specific mode of resistance. A non-specific mechanism was based on several defence genes probably induced by jasmonate and ethylene signalling, including lipid-transfer protein, thionin, defensin and GDSL-like lipase genes. Additionally, defence-related genes encoding jasmonate-regulated proteins were up-regulated in response to FHB. Another mechanism based on the targeted suppression of essential Fusarium virulence factors comprising proteases and mycotoxins was found to be an essential, induced defence of general relevance in wheat. Moreover, similar inductions upon fungal infection were frequently observed among FHB-responsive genes of both mechanisms in the cultivars Dream and Sumai 3. Conclusions Especially ABC transporter, UDP-glucosyltransferase, protease and protease inhibitor genes associated with the defence mechanism against fungal virulence factors are apparently active in different resistant genetic backgrounds, according to reports on other wheat cultivars and barley. This was further supported in our qPCR experiments on seven genes originating from this mechanism which revealed similar activities in the resistant cultivars Dream and Sumai 3. Finally, the combination of early-stage and steady-state induction was associated with resistance, while transcript induction generally occurred later and temporarily in the susceptible cultivars. The respective mechanisms are attractive for advanced studies aiming at new resistance and toxin management strategies.

2012-01-01

361

Cloning of a gene encoding flavin reductase coupling with dibenzothiophene monooxygenase through coexpression screening using indigo production as selective indication.  

PubMed

The thermophilic dibenzothiophene (DBT)-desulfurizing bacterium, Bacillus subtilis WU-S2B, possesses the ability to convert DBT to 2-hydroxybiphenyl with the release of inorganic sulfur over a wide temperature range up to 50 degrees C. The conversion is initiated by consecutive sulfur atom-specific oxidations by two monooxygenases, and flavin reductase is essential in combination with these flavin-dependent monooxygenases. The recombinant Escherichia coli cells expressing the DBT monooxygenase gene (bdsC) from B. subtilis WU-S2B also oxidize indole to blue pigment indigo in the presence of a heterologous flavin reductase. Thus, to clone a gene encoding flavin reductase from B. subtilis WU-S2B, indigo production by coexpression of the gene with bdsC in E. coli was used as a selection. Using this method, the corresponding gene (frb) was obtained from a recombinant strain forming a blue colony due to indigo production on a nutrient agar plate, and it was confirmed that this gene product Frb exhibited flavin reductase activity. The deduced amino acid sequence of frb consists of 174 amino acid residues and shares 61% identity with that of nitroreductase (YwrO) of Bacillus amyloliquefaciens. In addition, coexpression of frb with the DBT-desulfurization genes (bdsABC) from B. subtilis WU-S2B was critical for high DBT-desulfurizing ability over a wide temperature range of 20-55 degrees C. This coexpression screening using indigo production as selective indication may be widely applicable for cloning novel genes encoding either component of flavin reductase or flavin-dependent monooxygenase which efficiently couples with the other component in two-component monooxygenases. PMID:14697229

Furuya, Toshiki; Takahashi, Shusuke; Ishii, Yoshitaka; Kino, Kuniki; Kirimura, Kohtaro

2004-01-16

362

Tbx2/3 is an essential mediator within the Brachyury gene network during Ciona notochord development  

PubMed Central

T-box genes are potent regulators of mesoderm development in many metazoans. In chordate embryos, the T-box transcription factor Brachyury (Bra) is required for specification and differentiation of the notochord. In some chordates, including the ascidian Ciona, members of the Tbx2 subfamily of T-box genes are also expressed in this tissue; however, their regulatory relationships with Bra and their contributions to the development of the notochord remain uncharacterized. We determined that the notochord expression of Ciona Tbx2/3 (Ci-Tbx2/3) requires Ci-Bra, and identified a Ci-Tbx2/3 notochord CRM that necessitates multiple Ci-Bra binding sites for its activity. Expression of mutant forms of Ci-Tbx2/3 in the developing notochord revealed a role for this transcription factor primarily in convergent extension. Through microarray screens, we uncovered numerous Ci-Tbx2/3 targets, some of which overlap with known Ci-Bra-downstream notochord genes. Among the Ci-Tbx2/3 notochord targets are evolutionarily conserved genes, including caspases, lineage-specific genes, such as Noto4, and newly identified genes, such as MLKL. This work sheds light on a large section of the notochord regulatory circuitry controlled by T-box factors, and reveals new components of the complement of genes required for the proper formation of this structure.

Jose-Edwards, Diana S.; Oda-Ishii, Izumi; Nibu, Yutaka; Di Gregorio, Anna

2013-01-01

363

Post transcriptional regulation of chloroplast gene expression by nuclear encoded gene products. Progress report, June 1, 1990--June 30, 1992  

SciTech Connect

Many individual chloroplast genes require the products of a collection of nuclear genes for their successful expression. These nuclear gene products apparently work with great specificity, each committed to the expression of a single chloroplast gene. We have chosen as a model nuclear mutants of Chlamydomonas affected in different stages in the expression of the chloroplast encoded Photosystem II polypeptide, D2. We have made the progress in understanding how nuclear gene products affect the translation of the D2 encoding MRNA. Two nuclear genes are required for this process which have been mapped genetically. In contrast to other examples of nuclear control of translation in the chloroplast, these nuclear gene products appear to be required either for specific stages in translation elongation or for the post-translational stabilization of the nascent D2 protein. Pseudoreversion analysis has led us to a locus which may be directly involved in D2 expression. We have made considerable progress in pursuing the molecular basis of psbd MRNA stabilization. psbD 5` UTR specific transcripts have been synthesized in vitro and used in gel mobility shift assays. UV-crosslinking studies are underway to identify the transacting factors which bind to these sequences. The continued examination of these mutants will help us to understand how nuclear gene products work in this specific case of chloroplast gene expression, and will elucidate how two distinct genomes can interact generally.

Kuchka, M.R.

1992-08-01

364

SMC1: an essential yeast gene encoding a putative head-rod-tail protein is required for nuclear division and defines a new ubiquitous protein family  

Microsoft Academic Search

The smcl-1 mutant was identified initially as a mutant of Saccharomyces cerevisiae that had an elevated rate of minichromosome nondisjunction. We have cloned the wild-type SMC1 gene. The sequence of the SMC1 gene predicts that its product (Smclp) is a 141-kD protein, and antibodies against Smcl protein detect a protein with mobility of 165 kD. Analysis of the primary and

Alexander V. Strunnikov; Vladimir L. Larionov; Douglas Koshland

1993-01-01

365

Generation of broad-spectrum disease resistance by overexpression of an essential regulatory gene in systemic acquired resistance  

PubMed Central

The recently cloned NPR1 gene of Arabidopsis thaliana is a key regulator of acquired resistance responses. Upon induction, NPR1 expression is elevated and the NPR1 protein is activated, in turn inducing expression of a battery of downstream pathogenesis-related genes. In this study, we found that NPR1 confers resistance to the pathogens Pseudomonas syringae and Peronospora parasitica in a dosage-dependent fashion. Overexpression of NPR1 leads to enhanced resistance with no obvious detrimental effect on the plants. Thus, for the first time, a single gene is shown to be a workable target for genetic engineering of nonspecific resistance in plants.

Cao, Hui; Li, Xin; Dong, Xinnian

1998-01-01

366

Introduction, stable integration, and controlled expression of a chimeric adenovirus gene whose product is toxic to the recipient human cell.  

PubMed Central

The DNA-binding protein (DBP) encoded by human adenoviruses is a multifunctional polypeptide which plays a central role in regulating the expression of the viral genes. To gain a better understanding of the relationships between the various functions provided by DBP, an extensive collection of DBP mutants is essential. To this end we have constructed several permissive human cell lines which contain and express the DBP gene at high levels to allow propagation of otherwise lethal, nonrecoverable mutants of DBP. Because DBP is toxic to human cells, cell lines were constructed by using a vector in which the DBP gene is under the control of the dexamethasone-inducible promoter of the mouse mammary tumor virus. The low basal levels of DBP synthesis in the absence of dexamethasone allows isolation and propagation of these cells. Addition of dexamethasone enhances DBP production 50- to 200-fold, and within 8 h its synthesis from the single integrated copy of the chimeric gene is 5 to 15% of that observed during peak DBP synthesis in infected human cells in which hundreds of copies of the DBP gene serve as templates. At the nonpermissive temperature, adenovirus mutants with ts lesions in the DBP gene replicate their DNAs, express their late genes, and form infectious viral particles in these DBP+ cell lines but not in the parental HeLa cells. Images

Klessig, D F; Brough, D E; Cleghon, V

1984-01-01

367

[Association of porcine ATF4 gene polymorphism and production traits and analysis of gene expression].  

PubMed

In order to understand the function of gene ATF4 and identify new DNA markers involved in pig production traits, the cDNA fragment of porcine ATF4 was cloned and sequenced. Sequence comparison revealed an A159G substitution downstream of the initiation codon (ATG). We then carried out PCR-Alu?-RFLP analysis in Large white, Landrace, Tongcheng and Meishan pigs, followed by association analysis in F2 "Large white ×Meishan" resource family. In all the individuals tested, Large White and Landrace pigs possessed the AA genotype, while Meishan and Tongcheng pigs pos-sessed the GG genotype. Association analysis in F2 resource family showed that this site was highly associated with buttock fat thickness (BFT) (Pamp;0.01) and had significant effect on thorax-waist fat thickness (TFT), average backfat thickness (ABT), loin eye height (LEH), and loin eye area (LEA)(Pamp;0.05). Real-time PCR was used to analyze the expression patterns of porcine ATF4 gene in longissimus dorsi at different development stages of Large White and Meishan pigs. The results showed that the gene expression levels of ATF4 were low 65 days after conception and 3 days after birth, but no signifi-cant differences were observed in both breeds. Meanwhile, the expression levels of porcine ATF4 gene were up-regulated 60 days and 120 days after birth in both breeds and the expression level in Meishan pigs was obviously higher than that in Large White pigs. These data could lay the foundation for further study on the molecular mechanism of porcine ATF4 gene in lipid metabolism. PMID:22207380

Chen, Chao; Wu, Wang-Jun; Xiong, Yuan-Zhu

2011-12-01

368

Regulation of Capsule Synthesis and Cell Motility in Salmonella enterica by the Essential Gene igaA  

Microsoft Academic Search

Mutants of Salmonella enterica carrying the igaA1 allele, selected as able to overgrow within fibroblast cells in culture, are mucoid and show reduced motility. Mucoidy is caused by derepression of wca genes (necessary for capsule synthesis); these genes are regulated by the RcsC\\/YojN\\/RcsB phosphorelay system and by the RcsA coregulator. The induction of wca expression in an igaA1 mutant is

David A. Cano; Gustavo Dominguez-Bernal; Alberto Tierrez; Francisco Garcia-del Portillo; Josep Casadesus

369

The ACC1 gene, encoding acetylCoA carboxylase, is essential for growth in Ustilago maydis  

Microsoft Academic Search

Acetyl-CoA carboxylase [ACCase; acetylCoA: carbon dioxide ligase (ADP forming), EC 6.4.1.2] catalyses the ATP-dependent carboxylation of acetylCoA to form malonyl-CoA. We have amplified a fragment of the biotin carboxylase (BC) domain of the Ustilago maydis acetyl-CoA carboxylase (ACC1) gene from genomic DNA and used this amplified DNA fragment as a probe to recover the complete gene from a ?EMBL3 genomic

Andrew BaileyJohn; John Keon; John Owen; John Hargreaves

1995-01-01

370

The gene encoding pyolysin, the pore-forming toxin of Arcanobacterium pyogenes, resides within a genomic islet flanked by essential genes  

Microsoft Academic Search

The plo gene, encoding the Arcanobacterium pyogenes cholesterol-dependent cytolysin, pyolysin (PLO), was localized to a 2.7-kb genomic islet of reduced %G+C content and alternate codon usage frequency. This islet, conserved among isolates from diverse hosts and geographical locations, separated the housekeeping genes smc and ftsY, which are found adjacent in many prokaryotes. The ftsY and ffh genes, located downstream of

Stefani T. Rudnick; B. Helen Jost; J. Glenn Songer; Stephen J. Billington

2003-01-01

371

The essential Schizosaccharomyces pombe cdc23 DNA replication gene shares structural and functional homology with the Saccharomyces cerevisiae DNA43 (MCM10) gene  

Microsoft Academic Search

The fission yeast cdc23 gene is required for correct DNA replication: cdc23 mutants show reduced rates of DNA synthesis and become elongated after cell-cycle arrest. We have cloned the Schizosaccharomyces pombe cdc23 gene by complementation of the temperature-sensitive phenotype of cdc23-M36 and confirmed the identity of the gene by integrative mapping. Analysis of the DNA sequence reveals that cdc23 can

Stephen J. Aves; Nicholas Tongue; Andrew J. Foster; Elizabeth A. Hart

1998-01-01

372

A Vibrio harveyi insertional mutant in the cgtA (obg, yhbZ) gene, whose homologues are present in diverse organisms ranging from bacteria to humans and are essential genes in many bacterial species  

Microsoft Academic Search

The cgtA gene product is a member of the subfamily of small GTP-binding proteins that have been identified in diverse organisms ranging from bacteria to humans. In bacteria that sporulate or display another special developmental programme, this gene (referred to as cgtA, obg or yhbZ) appears to be involved in the regulation of these processes. However, this gene has also

Agata Czyz; Ryszard Zielke

373

The Werner syndrome gene product (WRN): a repressor of hypoxia-inducible factor-1 activity.  

PubMed

Werner syndrome (WS) is a rare autosomal disease characterized by the premature onset of several age-associated pathologies. The protein defective in WS patients (WRN) is a helicase/exonuclease involved in DNA repair, replication, transcription and telomere maintenance. Hypoxia-inducible factor-1 (HIF-1) is a decisive element for the transcriptional regulation of genes essential for adaptation to low oxygen conditions. HIF-1 is also implicated in the molecular mechanisms of ageing. Here, we show that the cellular depletion of WRN protein (by siRNA targeting) leads to increased HIF-1 complex stabilization and activation. HIF-1 activation in the absence of WRN involves the generation of mitochondrial reactive oxygen species (mtROS) since SkQ1, a mitochondrial-targeted antioxidant, and stigmatellin, an inhibitor of mitochondrial complex III, blocked increased HIF-1 levels. Ascorbate, an essential co-factor involved in HIF-1 stability, was decreased in WRN-depleted cells. Interestingly, expression levels of GLUT1, a known dehydroascorbic acid transporter, were also decreased in WRN-depleted cells. Ascorbate supplementation of WRN-depleted cells led to a dose-dependent inhibition of HIF-1 activation. These results indicate that WRN protein regulates HIF-1 activation by affecting mitochondrial ROS production and intracellular ascorbate levels. This work provides a novel mechanistic link between HIF-1 activity and different age-associated pathologies. PMID:22659133

Labbé, Adam; Lafleur, Véronique N; Patten, David A; Robitaille, Geneviève A; Garand, Chantal; Lamalice, Laurent; Lebel, Michel; Richard, Darren E

2012-08-15

374

Effect of Citrus reticulata and Cymbopogon citratus Essential Oils on Aspergillus flavus Growth and Aflatoxin Production on Asparagus racemosus  

Microsoft Academic Search

Essential oils extracted from Citrus reticulata and Cymbopogon citratus were tested in vitro against the toxigenic strain of Aspergillus flavus, isolated from the tuberous roots of Asparagus racemosus, used in preparation of herbal drugs. The essential oils completely inhibited the growth of A. flavus at 750 ppm and also exhibited a broad fungitoxic spectrum against nine additional fungi isolated from the

Priyanka Singh; Ravindra Shukla; Ashok Kumar; Bhanu Prakash; Shubhra Singh; Nawal Kishore Dubey

2010-01-01

375

RRN3 gene of Saccharomyces cerevisiae encodes an essential RNA polymerase I transcription factor which interacts with the polymerase independently of DNA template.  

PubMed Central

RRN3 is one of the RRN genes specifically required for the transcription of rDNA by RNA polymerase I (Pol I) in Saccharomyces cerevisiae. We have cloned the gene, determined the nucleotide sequence, and found that it is an essential gene which encodes a protein of calculated molecular weight of 72 369. Extracts prepared from rrn3 mutants were defective in in vitro transcription of rDNA templates. We used extracts from a strain containing an epitope-tagged Rrn3 protein to purify a factor that could complement the mutant extracts. Using immunoaffinity purification combined with Mono Q chromatography, we obtained an essentially pure preparation of Rrn3p which complements the mutant extracts. By carrying out template commitment experiments, we found that Rrn3p is not part of the pre-initiation complex that is stable through multiple rounds of transcription. We also found that pre-incubation of Rrn3p with purified Pol I leads to stimulation of transcription upon subsequent mixing with DNA template and other transcription reaction components. Single-round transcription experiments using the detergent Sarkosyl showed that this stimulation is due to increased efficiency of formation of a Sarkosyl-resistant pre-initiation complex. Thus, Rrn3p appears to interact directly with Pol I, apparently stimulating Pol I recruitment to the promoter, and is distinct from two other Pol I-specific transcription factors, the Rrn6/7 complex and the Rrn5/9/10 complex (UAF), characterized previously. Images

Yamamoto, R T; Nogi, Y; Dodd, J A; Nomura, M

1996-01-01

376

The Autographa californica multiple nucleopolyhedrovirus ie0-ie1 gene complex is essential for wild-type virus replication, but either IE0 or IE1 can support virus growth.  

PubMed

The immediate-early ie0-ie1 gene complex expresses the only baculovirus spliced gene that produces an alternate protein product. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) IE1 is a potent transcriptional transactivator that is essential for viral replication in transient assays. IE1 contains 582 amino acids that are arranged into different domains, including an acidic activation domain at the N terminus, a DNA binding domain, and an oligomerization domain at the C terminus. IE0 is a 52-amino-acid N-terminally elongated form of IE1. We investigated the functions of IE0 and IE1 in virus-infected cells by constructing the first ie1 open reading frame knockout virus. An infectious AcMNPV bacmid was used to generate the ie1 knockout, and the resulting virus, AcBacIE1KO, effectively deletes both ie0 and ie1. AcBacIE1KO does not infect Spodoptera frugiperda cells, showing that the ie0-ie1 gene complex is essential for viral infection. Rescue viruses of AcBacIE1KO were constructed that express only IE1, IE1 and IE0, or only IE0. Our results show that both IE0 and IE1 can function independently, but not equivalently, to support replication, producing infectious virus. Viruses expressing predominately, or only, IE0 produced significantly fewer cells with polyhedra than either the IE1 counterpart or wild-type virus. In addition, DNA replication was prolonged and budded virus and late gene expression were delayed. Viruses expressing only IE1 also produced fewer polyhedra, but replication was slightly faster and achieved higher levels than that of the wild-type virus. Both IE0 and IE1 are therefore required and must be expressed in the correct quantitative ratios to achieve a wild-type infection. PMID:15795248

Stewart, Taryn M; Huijskens, Ilse; Willis, Leslie G; Theilmann, David A

2005-04-01

377

Spink13, an Epididymis-specific Gene of the Kazal-type Serine Protease Inhibitor (SPINK) Family, Is Essential for the Acrosomal Integrity and Male Fertility*  

PubMed Central

Sperm maturation involves numerous surface modifications by a variety of secreted proteins from epididymal epithelia. The sperm surface architecture depends on correct localization of its components and highlights the importance of the sequence of the proteolytic processing of the sperm surface in the epididymal duct. The presence of several protease inhibitors from different families is consistent with the hypothesis that correctly timed epididymal protein processing is essential for proper sperm maturation. Here we show that the rat (Rattus norvegicus) epididymis-specific gene Spink13, an androgen-responsive serine protease inhibitor, could bind to the sperm acrosome region. Furthermore, knockdown of Spink13 in vivo dramatically enhanced the acrosomal exocytosis during the process of capacitation and thus led to a significant reduction in male fertility, indicating that Spink13 was essential for sperm maturation. We conclude that blockade of SPINK13 may provide a new putative target for post-testicular male contraceptives.

Ma, Li; Yu, Heguo; Ni, Zimei; Hu, Shuanggang; Ma, Wubin; Chu, Chen; Liu, Qiang; Zhang, Yonglian

2013-01-01

378

Essential role of the apoptotic cell engulfment genes draper and ced-6 in programmed axon pruning during Drosophila metamorphosis.  

PubMed

Axon pruning is a common phenomenon in neural circuit development. Previous studies demonstrate that the engulfing action of glial cells is essential in this process. The underlying molecular mechanisms, however, remain unknown. We show that draper (drpr) and ced-6, which are essential for the clearance of apoptotic cells in C. elegans, function in the glial engulfment of larval axons during Drosophila metamorphosis. The drpr mutation and glia-specific knockdown of drpr and ced-6 by RNA interference suppress glial engulfment, resulting in the inhibition of axon pruning. drpr and ced-6 interact genetically in the glial action. Disruption of the microtubule cytoskeleton in the axons to be pruned occurs via ecdysone signaling, independent of glial engulfment. These findings suggest that glial cells engulf degenerating axons through drpr and ced-6. We propose that apoptotic cells and degenerating axons of living neurons are removed by a similar molecular mechanism. PMID:16772168

Awasaki, Takeshi; Tatsumi, Ryoko; Takahashi, Kuniaki; Arai, Kunizo; Nakanishi, Yoshinobu; Ueda, Ryu; Ito, Kei

2006-06-15

379

The calnexin homologue cnx1+ in Schizosaccharomyces pombe, is an essential gene which can be complemented by its soluble ER domain.  

PubMed

Secretory proteins become folded by the action of a number of molecular chaperones soon after they enter the endoplasmic reticulum (ER). In mammalian cells, the ER membrane protein calnexin has been shown to be a molecular chaperone involved in the folding of secretory proteins and in the assembly of cell surface receptor complexes. We have used a PCR strategy to identify the Schizosaccharomyces pombe calnexin homologue, cnx1+. The cnx1+ encoded protein, Cnx1, was shown to be a calcium binding type I integral membrane glycoprotein. At its 5' end, the cnx1+ gene has consensus heat shock transcriptional control elements and was inducible by heat shock and by the calcium ionophore A23187. Unlike the sequence-related Saccharomyces cerevisiae CNE1 gene, the S.pombe cnx1+ gene was essential for cell viability. The full-length Cnx1 protein was able to complement the cnx1+ gene disruption but the full-length mammalian calnexin could not. The ER lumenal domain of Cnx1, which was secreted from cells, was capable of complementing the cnx1::ura4 lethal phenotype. The equivalent region of mammalian calnexin has been shown to possess molecular chaperone activity. It is possible that the lethal phenotype is caused by the absence of this chaperone activity in the S.pombe cnx1+ gene disruption. PMID:7621821

Parlati, F; Dignard, D; Bergeron, J J; Thomas, D Y

1995-07-01