CLPP OF BACILLUS-SUBTILIS IS REQUIRED FOR COMPETENCE DEVELOPMENT, MOTILITY, DEGRADATIVE ENZYME-SYNTHESIS, GROWTH AT HIGH-TEMPERATURE AND SPORULATION

The nucleotide sequence of the Bacillus subtilis clpP gene was determi ned, The predicted protein shows very high similarity to members of th e ClpP family of proteolytic subunits (68% amino acid sequence identit y with that of Escherichia coli), We show that ClpP plays an essential role in stationary phase adaptive responses, Indeed, a Delta clpP mut ant was constructed and shown to display a pleiotropic phenotype, incl uding a deficiency in both sporulation initiation and competence for D NA uptake, The Delta clpP mutant has a highly filamentous morphology a nd appears to be non-motile, as judged by swarm plate assays, Expressi on of clpP is strongly induced under heat shock conditions, and ClpP i s shown to be essential for growth of B. subtilis at high temperature, The role of ClpP in the sporulation and competence regulatory pathway s was investigated, ClpP is required for expression of the spollA and spollG operons, encoding the sigma(F) and sigma(E) sporulation-specifi c sigma factors, ClpP is also necessary for the expression of the comK gene, encoding a positive transcriptional regulator of competence gen es, ComK-dependent transcription of sacB, encoding the exocellular deg radative enzyme levansucrase, was found to be abolished in the Delta c lpP mutant, MecA has been characterized previously as a negative regul ator of comK expression, whose overproduction inhibits both sporulatio n and competence development, Expression of a mecA'-'lacZ translationa l fusion is shown to be increased in the Delta clpP mutant, We suggest that ClpP is involved in controlling MecA levels in the cell through proteolysis, Increased levels of MecA in the absence of ClpP are at le ast partly responsible for the observed pleiotropic phenotype of the D elta clpP mutant.