Stringent Response in Vibrio Cholerae: Genetic Analysis of spoT Gene Function and Identification of a Novel (p)ppGpp Synthetase Gene
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Title |
Stringent Response in Vibrio Cholerae: Genetic Analysis of spoT Gene Function and Identification of a Novel (p)ppGpp Synthetase Gene |
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Creator |
Das, Bhabatosh
Pal, Ritesh Ranjan Bag, Satyabrata Bhadra, Rupak K |
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Subject |
Infectious Diseases and Immunology
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Description |
RelA and SpoT of Gram-negative organisms critically regulate cellular levels of (p)ppGpp. Here, we have dissected the spoT gene function of the cholera pathogen Vibrio cholerae by extensive genetic analysis. Unlike Escherichia coli, V. cholerae DrelA DspoT cells accumulated (p)ppGpp upon fatty acid or glucose starvation. The result strongly suggests RelA-SpoT-independent (p)ppGpp synthesis in V. cholerae. By repeated subculturing of a V. cholerae DrelA DspoT mutant, a suppressor strain with (p)ppGpp0 phenotype was isolated. Bioinformatics analysis of V. cholerae whole genome sequence allowed identification of a hypothetical gene (VC1224), which codes for a small protein (~29 kDa) with a (p)ppGpp synthetase domain and the gene is highly conserved in vibrios; hence it has been named relV. Using E. coli DrelA or DrelA DspoT mutant we showed that relV indeed codes for a novel (p)ppGpp synthetase. Further analysis indicated that relV gene of the suppressor strain carries a point mutation at nucleotide position 676 of its coding region (DrelA DspoT relV676), which seems to be responsible for the (p)ppGpp0 phenotype. Analysis of a V. cholerae DrelA DspoT DrelV triple mutant confirmed that apart from canonical relA and spoT genes, relV is a novel gene in V. cholerae responsible for (p)ppGpp synthesis. |
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Publisher |
Blackwell Publishing
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Date |
2009
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Type |
Article
PeerReviewed |
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Format |
application/pdf
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Identifier |
http://www.eprints.iicb.res.in/1376/1/MOLECULAR_MICROBIOLOGY___72(_2)_380%2D398;2009[82].pdf
Das, Bhabatosh and Pal, Ritesh Ranjan and Bag, Satyabrata and Bhadra, Rupak K (2009) Stringent Response in Vibrio Cholerae: Genetic Analysis of spoT Gene Function and Identification of a Novel (p)ppGpp Synthetase Gene. Molecular Microbiology, 72 (2). pp. 380-398. |
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Relation |
http://dx.doi.org/10.1111/j.1365-2958.2009.06653.x
http://www.eprints.iicb.res.in/1376/ |
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