Suppression of temperature-sensitive sporulation mutation in the Bacillus subtilis sigA gene by rpoB mutation.
We isolated a temperature-sensitive sporulation defective mutant of the sigA gene, encoding a major sigma factor, sigma(A) protein, in Bacillus subtilis, and designated it as sigA21. The sigA21 mutation caused a single-amino acid substitution, E314K, in region 4 of the sigma(A) protein. In this mutant, expression of the spoIIG gene, whose transcription depends on both sigma(A) and the phosphorylated Spo0A protein, Spo0A approximately P, a major transcription factor during early stages of sporulation, was greatly reduced at 43 degrees C. To obtain further information on the mechanism of sigma(A) function during the early spore development, we isolated a spontaneous sporulation-proficient suppressor mutant at 43 degrees C. This extragenic suppressor mutation was mapped within the rpoB gene, encoding the beta subunit of RNA polymerase, and was found to have a single-amino acid substitution, A863G. In this mutant, the expression of the spoIIG is partially restored at 43 degrees C.
Nanamiya
H
H
Laboratory of Molecular Genetics, College of Science, Rikkyo University, Tokyo, Japan.
Fugono
N
N
Asai
K
K
Doi
R H
RH
Kawamura
F
F
D019943:Amino Acid Substitution; D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D006358:Hot Temperature; D009154:Mutation; D012808:Sigma Factor / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D013171:Spores, Bacterial / Q000502:physiology; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit