Two RNA polymerase sigma factors from Bacillus subtilis discriminate between overlapping promoters for a developmentally regulated gene

Abstract

A developmentally regulated gene (spoVG) from the spore-forming bacterium B. subtilis is expressed from 2 overlapping promoters, which direct transcription initiating from sites separated by 10 base pairs. Utilization of the upstream promoter is determined by an RNA polymerase .sigma. factor of MW 37,000 (.sigma.37). The isolation of a 32,000 MW species of .sigma. factor (.sigma.32), which exclusively dictates transcription initiation from the downstream promoter, is reported. A model for the way in which .sigma.-specific recognition sequences are intermeshed within the spoVG transcription initiation region is suggested.