Analysis of an anaerobically induced promoter for the cobalamin biosynthetic genes in Salmonella typhimurium.
We have identified an anaerobically induced promoter for the cobalamin biosynthetic (cob) genes. In a plasmid the Cob promoter showed two of the three types of control of the intact chromosomal Cob operon: anaerobic induction and cAMP stimulation. Cobalamin repression was observed only in promoter fragments which included sequences far downstream of the transcription start site, suggesting that this control is post-transcriptional. One anaerobically induced transcript was identified and its 5' end was determined. Deletion mapping showed that 60 nucleotides upstream of the start site were sufficient for anaerobic synthesis of this transcript. Upstream of the transcription start site a putative sigma 70-dependent -10 recognition sequence was identified; however, no consensus -35 region was observed.
Richter-Dahlfors
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AA
Department of Microbiology, University of Uppsala, Sweden.
Andersson
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DI
D000693:Anaerobiosis; D001483:Base Sequence; D004252:DNA Mutational Analysis; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism; D014805:Vitamin B 12 / Q000096:biosynthesis / Q000235:genetics*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase; D014805:Vitamin B 12