Identification of σV-dependent genes of Bacillus subtilis

The chromosome of Bacillus subtilis codes for seven extracytoplasmic function sigma factors the activity of which is modulated normally by a cognate anti-sigma factor. While inducing factors and genes for four of them (σM, σW, σX, and σY) have been identified, those of the remaining three sigma factors including σV remain elusive. The objective of the present study was the unequivocal identification of its anti-sigma factor and of genes controlled by σV. In many cases reported so far the gene coding for the anti-sigma factor is located immediately downstream of the gene coding for the sigma factor, and both form a bicistronic operon. We could show by two different experimental approaches that this is also the case for sigV and rsiV. Under conditions of overproduction of σV, 13 genes could be identified being induced several-fold by the DNA macroarray technique. Induction of three of them was confirmed by Northern blots, and the potential promoter of sigV was identified by primer extension. This led to the deduction of a consensus sequence recognized by σV.