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首页> 外文期刊>Journal of bacteriology >icaR Encodes a Transcriptional Repressor Involved in Environmental Regulation of ica Operon Expression and Biofilm Formation in Staphylococcus epidermidis
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icaR Encodes a Transcriptional Repressor Involved in Environmental Regulation of ica Operon Expression and Biofilm Formation in Staphylococcus epidermidis

机译：icaR编码转录抑制因子，参与环境调控表皮葡萄球菌中ica操纵子表达和生物膜形成。

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Biofilm formation in Staphylococcus epidermidis is dependent upon the ica operon-encoded polysaccharide intercellular adhesin, which is subject to phase-variable and environmental regulation. The icaR gene, located adjacent to the ica operon, appears to be a member of the tetR family of transcriptional regulators. In the reference strain RP62A, reversible inactivation of the ica operon by IS256 accounts for 25 to 33% of phase variants. In this study, icaA and icaR regulation were compared in RP62A and a biofilm-forming clinical isolate, CSF41498, in which IS256 is absent. Predictably, ica operon expression was detected only in wild-type CSF41498 and RP62A but not in non-IS256-generated phase variants. In contrast, the icaR gene was not expressed in RP62A phase variants but was expressed in CSF41498 variants. An icaR::Emr insertion mutation in CSF41498 resulted in an at least a 5.8-fold increase in ica operon expression but did not significantly alter regulation of the icaR gene itself. Activation of ica operon transcription by ethanol in CSF41498 was icaR dependent. In contrast, a small but significant induction of ica by NaCl and glucose (NaCl-glucose) was observed in the icaR::Emr mutant. In addition, transcription of the icaR gene itself was not significantly affected by NaCl-glucose but was repressed by ethanol. Expression of the ica operon was induced by ethanol or NaCl-glucose in phase variants of CSF41498 (icaR+) but not in RP62A variants (icaR deficient). These data indicate that icaR encodes a repressor of ica operon transcription required for ethanol but not NaCl-glucose activation of ica operon expression and biofilm formation.
机译：表皮葡萄球菌的生物膜形成依赖于 ica 操纵子编码的多糖细胞间粘附素，该粘附素受相变和环境调控。与 ica 操纵子相邻的 icaR 基因似乎是转录调节子 tetR 家族的成员。在参考菌株RP62A中，IS 256 对 ica 操纵子的可逆失活占相变体的25％至33％。在这项研究中，比较了RP62A和不含生物膜的临床分离株CSF41498（其中没有IS 256 ）中的 icaA 和 icaR 调控。可以预见，仅在野生型CSF41498和RP62A中检测到 ica 操纵子表达，而在非IS 256 产生的相变中则未检测到。相反， icaR 基因在RP62A相变体中不表达，而在CSF41498相变体中表达。 CSF41498中的 icaR :: Em r 插入突变导致 ica 操纵子表达增加至少5.8倍，但没有明显改变icaR 基因本身的调控。乙醇在CSF41498中激活 ica 操纵子转录是 icaR 依赖性的。相比之下，在 icaR :: Em r 突变体中观察到了NaCl和葡萄糖（NaCl-葡萄糖）对 ica 的少量但显着诱导。此外， icaR 基因本身的转录不受NaCl葡萄糖影响不明显，但受乙醇抑制。乙醇或NaCl葡萄糖在CSF41498（ icaR + ）的相位变体中诱导 ica 操纵子的表达，而在RP62A变体（ em> icaR 缺陷）。这些数据表明 icaR 编码乙醇所需的 ica 操纵子转录阻遏物，而不是 ica 操纵子表达和生物膜形成的NaCl-葡萄糖激活。

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