Separation and analysis of the RNA polymerase binding sites of a complex Bacillus subtilis promoter

The Bacillus subtilis veg promotor site was shown to be composed of two neighboring RNA polymerase binding sites, only one of which ("Site I") produces a transcript. The relationship between these sites has been investigated following insertion of ten base pairs of DNA between the sites and subsequent cloning of each site independent of the other, and deletion of DNA sequences upstream from the productive site. The effect of DNA insertion was to permit transcription initiation from the previously nonproductive Site II, in either the presence or absence of Site I. This could be attributed to insertion of a purine residue seven base pairs downstream from the Pribnow box of Site II. Transcription from Site I was slightly increased in the presence of Site II in cis, but was still efficient in the absence of Site II, indicating that there is no absolute dependence on Site II for in vitro transcription from Site I.