title: Genetic evidence for involvement of the alternative sigma factor SigI in controlling expression of the cell wall hydrolase gene lytE and contribution of LytE to heat survival of Bacillus subtilis.
abstract: The Bacillus subtilis cell wall hydrolase LytE is involved in cell wall turnover and cell separation during vegetative growth. lytE transcription is known to be driven by a YycF-activated SigA-dependent promoter. The cell wall regulator SigI is an alternative sigma factor that has been shown to be heat stress-inducible and to be essential for survival of B. subtilis at high temperature. However, none of the previously identified target genes of SigI contribute to heat resistance. We now demonstrate that lytE expression is heat-inducible and that heat induction of lytE expression is strongly dependent on SigI. We have also found that the lytE mutant shows the same growth defect at high temperature as the sigI mutant. Introducing an extra copy of lytE into the sigI mutant could rescue its growth defect. Our data strongly suggest that SigI-dependent lytE expression under heat stress is important for heat survival of B. subtilis.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China.
authors.forename: Chi-Ling
authors.initials: CL
authors.lastname: Tseng
authors.forename: Jung-Tze
authors.initials: JT
authors.lastname: Chen
authors.forename: Ju-Hui
authors.initials: JH
authors.lastname: Lin
authors.forename: Wan-Zhen
authors.initials: WZ
authors.lastname: Huang
authors.forename: Gwo-Chyuan
authors.initials: GC
authors.lastname: Shaw
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002473:Cell Wall / Q000201:enzymology; D015964:Gene Expression Regulation, Bacterial; D006358:Hot Temperature; D050296:Microbial Viability; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics* / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C422477:SigI protein, Bacillus subtilis; D012808:Sigma Factor; C112181:LytE protein, Bacillus subtilis; D009238:N-Acetylmuramoyl-L-alanine Amidase