A previously unidentified sigma factor and two accessory proteins regulate oxalate decarboxylase expression in Bacillus subtilis.
We have investigated the function of a cell envelope stress-inducible gene, yvrI, which encodes a 22.5 kDa protein that includes a predicted sigma(70) region 4 domain, but lacks an apparent region 2 domain. YvrI interacts with RNA polymerase and overexpression of YvrI results in induction of OxdC, an oxalate decarboxylase maximally expressed under low-pH conditions. We have used microarray-based analyses to define the YvrI regulon. YvrI is required for the transcription of three operons (oxdC-yvrL, yvrJ and yvrI-yvrHa) each of which is preceded by a highly similar promoter sequence. Activation of these promoters requires both YvrI and the product of the second gene in the yvrI-yvrHa operon, YvrHa. YvrI and YvrHa together allow recognition of the oxdC promoter, stimulate DNA melting and activate transcription by core RNA polymerase. Together, these results suggest that YvrI is a previously unrecognized sigma factor in Bacillus subtilis and that the 9.5 kDa YvrHa protein acts as a required co-activator of transcription. A yvrL deletion results in the upregulation of YvrI activity suggesting that YvrL is a negative regulator of YvrI-dependent transcription, possibly functioning as an anti-sigma factor.
Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
Shawn R
SR
MacLellan
Tina
T
Wecke
John D
JD
Helmann
D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000235:genetics*; D004790:Enzyme Induction; D015964:Gene Expression Regulation, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D011401:Promoter Regions, Genetic; D018085:Regulon; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D012808:Sigma Factor; D002262:Carboxy-Lyases; C021915:oxalate decarboxylase