Bacillus subtilis early sporulation genes kinA, spo0F, and spo0A are transcribed by the RNA polymerase containing sigma H.

The Bacillus subtilis genes kinA (spoIIJ), spo0F, and spo0A encode components of the sporulation signal transduction pathway. Recent work has suggested that these genes are transcribed by a minor form of RNA polymerase, E sigma H (sigma H is the product of spo0H, another early sporulation gene). We directly tested this hypothesis by performing in vitro transcription assays with reconstituted E sigma H and a set of plasmids containing the kinA, spo0F, and spo0A promoter regions. We were able to obtain distinct transcripts of the expected sizes with all three genes by using linearized or supercoiled templates. Furthermore, primer extension experiments indicate that the transcription start sites for the three genes in vitro and in vivo are the same. In addition, we measured steady-state levels of kinA, spo0F, and spo0A mRNAs during growth in sporulation medium; all of them were increased at or near the beginning of the stationary phase.