Dual regulatory pathways integrating the RcsC-RcsD-RcsB signalling system control enterohaemorrhagic Escherichia coli pathogenicity

Toru Tobe, Hiroki Ando, Hiroko Ishikawa, Hiroyuki Abe, Kosuke Tashiro, Tetsuya Hayashi, Satoru Kuhara, Nakaba Sugimoto

研究成果: ジャーナルへの寄稿学術誌査読

51 被引用数 (Scopus)

抄録

Bacterial pathogenesis is strictly regulated in response to changes in environmental conditions. A His-Asp phosphorelay system consisting of a sensor kinase and response regulator is used by Gram-positive and Gram-negative bacteria to control gene expression in response to environmental stimuli. We screened His-Asp phosphorelay systems for their effect on virulence expression in enterohaemorrhagic Escherichia coli (EHEC), and found rcsD or rcsB overexpression enhanced locus for enterocyte effacement (LEE) gene transcription and adherence to Caco-2 cells through transcriptional activation of the ler regulatory gene. An EHEC-specific regulator GrvA, encoded by ECs1274, was required for ler transcription activation by RcsB. Furthermore, GrvA activated ler transcription in E. coli K12. Stimulation of the RcsDCB regulatory system by RcsF overexpression slightly increased EspB expression in the wild type but not the ECs1274 mutant. However, EspB expression in an rcsB deletion mutant increased compared with wild type, suggesting that RcsB negatively regulates LEE gene expression and that active RcsB protein is present under normal growth conditions. Deletion of pchA, which encodes a positive regulator for ler, abolished the effect of the rcsB deletion, suggesting that pchA mediated the negative RcsB effect. pchA transcript levels decreased when RcsB expression increased. Thus, LEE gene transcription may be regulated by RcsB through two oppositely regulated O157-specific regulators, PchA and GrvA.

本文言語英語
ページ(範囲)320-333
ページ数14
ジャーナルMolecular Microbiology
58
1
DOI
出版ステータス出版済み - 10月 2005

!!!All Science Journal Classification (ASJC) codes

  • 微生物学
  • 分子生物学

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