SPORULATION PROTEIN SPOIVFB FROM BACILLUS-SUBTILIS ENHANCES PROCESSING OF THE SIGMA-FACTOR PRECURSOR PRO-SIGMA(K) IN THE ABSENCE OF OTHER SPORULATION GENE-PRODUCTS

Processing of inactive pro-sigma(K) to active sigma(K) in the mother cell compartment of sporulating Bacillus subtilis is governed by a signal transduction pathway emanating from the forespore and involving SpoIVFB in the mother cell. Coexpression of spoIVFB and sigK (encoding pro-sigma(K)) genes in growing B. subtilis or Esherichia coli enhanced pro-sigma(K) processing in the absence of other sporulation-specific gene products. The simplest explanation of these results is that SpoIVFB is a protease that processes pro-sigma(K).