PMID:8320211

Citation	Boylan, SA, Redfield, AR and Price, CW (1993) Transcription factor sigma B of Bacillus subtilis controls a large stationary-phase regulon. J. Bacteriol. 175:3957-63
Abstract	Transcription factor sigma B of Bacillus subtilis is active during the stationary growth phase, but its physiological role remains unknown. Understanding the function and regulation of genes controlled by sigma B (csb genes) should provide important clues to sigma B function in stationary-phase cells. To this end, we used a genetic approach to identify six new csb genes. This strategy relies on two elements: (i) random transcriptional fusions between the Escherichia coli lacZ gene and genes on the B. subtilis chromosome, generated in vivo with transposon Tn917lacZ, and (ii) a plate transformation technique to introduce a null sigB mutation into the fusion-bearing recipients directly on indicator plates. This strategy allowed the comparison of fusion expression in strains that were isogenic save for the presence or absence of a functional sigma B protein. Beginning with 1,400 active fusions, we identified 11 that were wholly or partly controlled by sigma B. These fusions mapped to six different loci that exhibit substantial contrasts in their patterns of expression in the logarithmic and stationary growth phases, suggesting that they participate in diverse cellular functions. However, for all six loci, the sigma B-dependent component of their expression was manifest largely in the stationary phase. The high frequency of six independent csb loci detected in a random collection of 1,400 fusions screened, the fact that four of the six new loci were defined by a single fusion, and the absence of the previously identified ctc and csbA genes in the present collection strongly suggest that sigma B controls a large stationary-phase regulon.
Links	PubMed PMC204823
Keywords	Bacillus subtilis/genetics; Bacillus subtilis/growth & development; Bacterial Proteins/genetics; Cell Division/physiology; Chromosome Mapping; Chromosomes, Bacterial; Gene Expression Regulation, Bacterial; Recombinant Fusion Proteins/genetics; Sigma Factor/genetics; Transcription Factors/genetics; Transformation, Genetic; beta-Galactosidase/biosynthesis; beta-Galactosidase/genetics
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
BACSU:RPSB		GO:0016987: sigma factor activity	ECO:0000315:		F		The authors performed transformations on B. subtilis in order to inactivate the sigma B factor by introducing a null sigma B factor mutation. These bacteria had a socB1 frameshift mutation which inhibited a negative regulator of Sigma B factor, thus increasing the amount of sigma B factor produced in cells without the null mutation of sigma B factor, increasing the experiments sensitivity. They then monitored the gene expression of the bacteria by measuring the amount of b-galactosidase activity produced within them due to a lacz fusion with random genes on the B.subtilis genome. By locating the the fusion and measuring their activity, they found which genes were dependent to an extent on sigma B factor for activation by finding those with altered B-galactosidase activity.	complete CACAO 11559
9CAUD:A0A0K2D0H6		GO:0016987: sigma factor activity	ECO:0000317:	UniProtKB:P06574	F		HHpred consistently showed the first section of the gene being homologous to a B.subtilis sigma factor followed by a translocase. For its similarity to sigma B factor, it had a probability of 99.97 and a E-value of 1.3e-28. In addition, numerous blast results showed many B. subtitles sigma factors with reasonable similarity to the first portion of the gene. The best blast result for sigma factor B had a query cover of 43% and a E-value of 5e-27. This strongly suggests that this gene is homologous to sigma factor B as well as sigma factors from B. subtilis in general, suggesting that it likely functions as one.	complete CACAO 11562

References

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