title: Characterization of RNA polymerase and two sigma-factor genes from Mycobacterium smegmatis.
abstract: A search for Mycobacterium smegmatis genes showing similarity to the conserved family encoding major sigma factors in diverse prokaryotes has identified two such determinants. Both genes are expressed in exponentially growing cells, as judged by Western immunoassays. A series of chromatographic steps was used to purify M. smegmatis RNA polymerase holoenzyme and it was shown that its ability to initiate in vitro transcription with a heterologous Bacillus subtilis promoter is dependent on the presence of these sigma factor(s). Reconstitution of specific in vitro transcription activity was obtained upon mixing of M. smegmatis core RNA polymerase with the major sigma factor of Bacillus subtilis. We also demonstrated in vitro transcription of the M. smegmatis rrnB promoter by the M. smegmatis RNA polymerase. Significantly, highly active B. subtilis RNA polymerase holoenzyme was unable to transcribe this gene.
authors.affiliation: Department of Microbiology, Public Health Research Institute, New York, New York 10016, USA.
authors.forename: M
authors.initials: M
authors.lastname: Predich
authors.forename: L
authors.initials: L
authors.lastname: Doukhan
authors.forename: G
authors.initials: G
authors.lastname: Nair
authors.forename: I
authors.initials: I
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000302:isolation & purification; D004790:Enzyme Induction; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000201:enzymology / Q000235:genetics*; D009166:Mycobacterium leprae / Q000235:genetics; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D017385:Sequence Homology; D012808:Sigma Factor / Q000235:genetics*; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C093499:MysB protein, Mycobacterium smegmatis; D012808:Sigma Factor; C093498:mysA protein, Mycobacterium smegmatis; D012321:DNA-Directed RNA Polymerases