Regulatory nucleotides involved in the Rel function of Bacillus subtilis

Abstract

Accumulation of polyphosphorylated nucleotides in B. subtilis in relation to the function of the rel gene was examined. During inhibition of isoleucine activation by O-methylthreonine, wild-type B. subtilis cells accumulate unusual nucleotides with the chromatographic and chemical properties of pppApp, ppApp, pppGpp, ppGpp, pGpp and ppGp. During the C source downshift elicited by inhibiting glucose uptake, accumulation of the polyphosphorylated guanosine but not adenosine nucleotides was observed. At the end of log phase in sporulation medium, a small transient accumulation of the polyphosphorylated guanosine but not adenosine nucleotides was observed. No nucleotide with chromatographic behavior expected for pppAppp could be detected under any conditions. The rel mutant of Swanton and Edlin did not accumulate any of these polyphosphorylated nucleotides under any conditions examined. The rel mutant is unimpaired in sporulation. One or more of the nucleotides detected may be involved in controlling specificity of transcription during the stringent response but none are required for sporogenesis.