title: Conservation of sigma F in mycobacteria and its expression in Mycobacterium smegmatis.
abstract: Alternate sigma factor SigF controls the expression of virulence-associated genes and is believed to contribute to the pathology of tuberculosis. It was reported to be absent in fast-growing nontuberculous mycobacteria until its orthologs were reported recently in a database. In this study, we demonstrate the presence of sigF gene in few commonly studied nonpathogenic mycobacterial species. Further, we studied the sigF expression in Mycobacterium smegmatis and observed that unlike its late-stage expression in M. tuberculosis and M. bovis, found in earlier studies, sigF is expressed throughout the growth in M. smegmatis, by and large, at the same level, but its expression varies upon exposure to different stress conditions. The presence of sigF orthologs in nontuberculous mycobacteria and its continued expression throughout the growth suggests that apart from regulating the expression of virulence factor genes in pathogenic mycobacteria, SigF is likely to have more roles in the mycobacterial physiology.
authors.affiliation: Division of Microbiology, Central Drug Research Institute, Post Box No. 173, M G Road, Lucknow, 226 001, India.
authors.forename: Anirudh K
authors.initials: AK
authors.lastname: Singh
authors.forename: Bhupendra N
authors.initials: BN
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D018869:Heat-Shock Response; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000502:physiology; D018384:Oxidative Stress; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D012808:Sigma Factor / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor