Regulation of the Bacillus subtilis Extracytoplasmic Function Protein σ Y and Its Target Promoters

Abstract
The Bacillus subtilis extracytoplasmic function sigma factor σ Y is of unknown function. We demonstrate that the sigY operon is expressed from an autoregulatory promoter site, P Y . We selected for transposon-induced mutations that upregulate P Y transcription in an attempt to identify genes involved in σ Y regulation. The resulting insertions disrupted yxlC , the gene immediately downstream of sigY . However, the phenotype of the yxlC ::Tn 10 insertion was due to polarity on the downstream genes of the sigY operon; a nonpolar insertion in yxlC did not lead to derepression of P Y . Further analyses revealed that both yxlD and yxlE encoded proteins important for the negative regulation of σ Y activity. A comparison of the transcriptomes of wild-type and yxlC ::Tn 10 mutant strains revealed elevated expression of several operons. However, only one additional gene, ybgB , was unambiguously identified as a direct target for σ Y . This was supported by analysis of direct targets for σ Y transcription with whole-genome runoff transcription followed by macroarray analysis.

This publication has 32 references indexed in Scilit: