Role of the sporulation protein BofA in regulating activation of the Bacillus subtilis developmental transcription factor σ(K)

Abstract

During sporulation, the Bacillus subtilis transcription factor σ(K) is activated by regulated proteolytic processing. I have used a system that facilitates the analysis of the contributions of a modified form of the processing enzyme, SpoIVFB-GFP, and the regulatory proteins BofA and SpoIVFA to the conversion of pro-σ(K) to σ(K). The results show that in the presence of BofA, SpoIVFA levels increase by greater than 20-fold, SpoIVFA is substantially stabilized, and pro-σ(K) processing is inhibited. In addition, enhanced accumulation of the SpoIVFA protein in the absence of BofA (achieved through the use of an ftsH null mutation) substantially inhibits pro-σ(K) processing. These results suggest that during growth, increased accumulation of the SpoIVFA protein inhibits the activity of SpoIVFB-GFP and regulates the activation of σ(K).