3D-01 Function analysis of relA gene and it's paralogous genes, yjbM and ywaC, in Bacillus subtilis

We constructed a disrupted mutation of relA gene in Bacillus subtilis to clarify the function of RelA in more details. We found that the relA disrupted mutant grew more slowly than the wild-type cells. In addition, transcription of the rRNA operon from its P1 promoter was extremely decreased in the relA disrupted mutant. However, growth arrests were found in both wild type and relA mutant cells under amino acid starvation. These results suggest that the unknown gene product(s), except for relA, would be required for the stringent response in Bacillus subtilis. On the other hand, two genes, yjbM, and ywaC, are assigned to encode the paralogous gene product of RelA. We constructed the disrupted mutation of yjbM and ywaC. We also obtained the relA yjbM ywaC triple disrupted mutant. We found that the triple disrupted mutant cells showed relaxed growth even though the cells were encountered amino acid starvation. In addition, transcription activity of the rRNA operon from its P1 promoter was restored in the triple mutant.