Sequential activation of dual promoters by different sigma factors maintains spoVJ expression during successive developmental stages of Bacillus subtilis.

The spoVJ gene of Bacillus subtilis encodes a 36 kDa protein and is expressed only in the mother cell. spoVJ has an interesting pattern of regulation during sporulation because it is expressed from sequentially activated promoters. These promoters, designated P1 and P2, are under the control of different sigma factors, sigma E and sigma K, which become active at separate times during sporulation. Removal of promoter P1, leaving promoter P2 active, resulted in about a 30-minute delay in the formation of heat-resistant spores and demonstrated that the expression of spoVJ from both promoters is essential for normal sporulation. A comparison is made between the sequences of the spoVJ promoters and the promoters of other genes dependent upon sigma E and sigma K.