Expression of guanyl-specific ribonuclease genes of Bacillus intermedius and Bacillus pumilus is regulated by the PhoP-PhoB two-component signal-transduction system of the PHO regulon in recombinant Bacillus subtilis strains

Promoters of the genes of guanyl-specific ribonucleases of Bacillus interme dius (binase) and Bacillus pumilus (RNase Bp) were found to contain sequenc es homologous to those recognizable by the regulatory protein PhoP in the p romoters of the PHO regulon of B. subtilis, as well as regions partially ho mologous to the binding sites of another regulatory protein, PhoB, in the p romoters of the PHO regulon of Escherichia coli. The role of the two-compon ent regulatory systems PhoP-PhoR and PhoB-PhoR in the regulation of express ion of the genes of binase and RNase Bp in recombinant strains of B. subtil is and E. coli was studied by using mutant strains; It was established that the expression of these genes in recombinant B. subtilis cells is stringen tly controlled by the PhoP-PhoR two-component regulatory system, whereas th e expression of these genes in E. coli cells is not controlled by the regul atory proteins PhoB or PhoR. presumably, regulatory systems of the response to phosphate starvation, analogous to the PHO regulon of B. subtilis, also function in other representatives of the genus Bacillus.