title: The Mycobacterium tuberculosis mysB gene product is a functional equivalent of the Escherichia coli sigma factor, KatF.
abstract: Mycobacterium tuberculosis, the causative agent of tuberculosis, may remain dormant within its host for many years. The nature of this dormant or latent state is not known, but it may be a specialized form of the stationary growth phase. In Escherichia coli, KatF (or RpoS) is the major stationary phase sigma factor regulating an array of genes expressed in this phase of growth. A potential M. tuberculosis katF homologue was cloned using a fragment of the E. coli katF gene as a probe. DNA sequence analysis of a resultant clone showed 100% identity to a fragment of DNA encoding the M. tuberculosis mysA and mysB genes. Overexpression of mysB in M. bovis BCG resulted in an increase in katG mRNA and catalase and peroxidase activity, and an increase in sensitivity of the cells to isoniazid. An increase in katG promoter activity from a reporter vector was demonstrated when mysB was overexpressed from the same plasmid, indicating a direct relationship between MysB and katG expression.
authors.affiliation: Department of Medical Microbiology, University of Cape Town and Groote Schuur Hospital, Observatory, South Africa.
authors.forename: N J
authors.initials: NJ
authors.lastname: Mulder
authors.forename: R E
authors.initials: RE
authors.lastname: Powles
authors.forename: H
authors.initials: H
authors.lastname: Zappe
authors.forename: L M
authors.initials: LM
authors.lastname: Steyn
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D015139:Blotting, Southern; D002374:Catalase / Q000378:metabolism; D015342:DNA Probes; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D007538:Isoniazid / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009163:Mycobacterium bovis / Q000187:drug effects / Q000235:genetics; D020102:Mycobacterium smegmatis / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000502:physiology; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000235:genetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics / Q000502:physiology*; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D015342:DNA Probes; D004269:DNA, Bacterial; C093499:MysB protein, Mycobacterium smegmatis; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C093498:mysA protein, Mycobacterium smegmatis; C069567:sigma factor KatF protein, Bacteria; D010544:Peroxidases; D002374:Catalase; C076136:catalase HPI; D009195:Peroxidase; D008156:Luciferases; D015719:Single-Strand Specific DNA and RNA Endonucleases; D007538:Isoniazid