Mutation in yaaT leads to significant inhibition of phosphorelay during sporulation in Bacillus subtilis.
In the course of a Bacillus subtilis functional genomics project which involved screening for sporulation genes, we identified an open reading frame, yaaT, whose disruptant exhibits a sporulation defect. Twenty-four hours after the initiation of sporulation, most cells of the yaaT mutant exhibited stage 0 of sporulation, indicating that the yaaT mutation blocks sporulation at an early stage. Furthermore, the mutation in yaaT led to a significant decrease in transcription from a promoter controlled by Spo0A, a key response regulator required for the initiation of sporulation. However, neither the level of transcription of spo0A, the activity of sigma(H), which transcribes spo0A, nor the amount of Spo0A protein was severely affected by the mutation in yaaT. Bypassing the phosphorelay by introducing an spo0A mutation (sof-1) into the yaaT mutant suppressed the sporulation defect, suggesting that the yaaT mutation interferes with the phosphorelay process comprising Spo0F, Spo0B, and histidine kinases. We also observed that mutation of spo0E, which encodes the phosphatase that dephosphorylates Spo0A-P, suppressed the sporulation defect in the yaaT mutant. These results strongly suggest that yaaT plays a significant role in the transduction of signals to the phosphorelay for initiation of sporulation. Micrographs indicated that YaaT-green fluorescent protein localizes to the peripheral membrane, as well as to the septum, during sporulation.
Hosoya
Shigeo
S
International Environmental and Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Asai
Kei
K
Ogasawara
Naotake
N
Takeuchi
Michio
M
Sato
Tsutomu
T
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017422:Sequence Analysis, DNA; D012808:Sigma Factor; D015398:Signal Transduction; D013171:Spores, Bacterial / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D012808:Sigma Factor; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus