GENETIC-CONTROL OF BACTERIAL SUICIDE - REGULATION OF THE INDUCTION OFPBSX IN BACILLUS-SUBTILIS

PBSX is a phage-like bacteriocin (phibacin) of Bacillus subtilis 168. Bacteria carrying the PBSX genome are induced by DNA damaging agents t o lyse and produce PBSX particles. The particles cannot propagate the PBSX genome. The particles produced by this suicidal response kill str ains nonlysogenic for PBSX. A 5.2-kb region which controls the inducti on of PBSX has been sequenced. The genes identified include the previo usly identified repressor gene xre and a positive control factor gene, pcf. Pcf is similar to known sigma factors and acts at the late promo ter P-L, which has been located distal to pcf. The first two genes exp ressed from the late promoter show homology to genes encoding the subu nits of phage terminases.