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首页> 外文期刊>Infection and immunity >HosA, a Member of the SlyA Family, Regulates Motility in Enteropathogenic Escherichia coli
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HosA, a Member of the SlyA Family, Regulates Motility in Enteropathogenic Escherichia coli

机译：HosA，SlyA家族的成员，调节肠道致病性大肠杆菌的运动。

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In enteropathogenic and enterohemorraghic Escherichia coli (EPEC and EHEC), two members of the SlyA family of transcriptional regulators have been identified as SlyA. Western blot analysis of the wild type and the corresponding hosA and slyA deletion mutants indicated that SlyA and HosA are distinct proteins whose expression is not interdependent. Of 27 different E. coli strains (EPEC, EHEC, enteroinvasive, enteroaggregative, uropathogenic, and commensal) examined, 14 were positive for both genes and proteins. To investigate hosA expression, a hosA::luxCDABE reporter gene fusion was constructed. hosA expression was significantly reduced in the hosA but not the slyA mutant and was influenced by temperature, salt, and pH. In contrast to SlyA, HosA did not activate the cryptic E. coli K-12 hemolysin ClyA. Mutation of hosA did not influence type III secretion, the regulation of the LEE1 and LEE4 operons, or the ability of E2348/69 to form attaching-and-effacing lesions on intestinal epithelial cells. HosA is, however, involved in the temperature-dependent positive control of motility on swim plates and regulates fliC expression and FliC protein levels. In electrophoretic mobility shift assays, purified HosA protein bound specifically to the fliC promoter, indicating that HosA directly modulates flagellin expression. While direct examination of flagellar structure and the motile behavior of individual hosA cells grown in broth culture at 30°C did not reveal any obvious differences, hosA mutants, unlike the wild type, clumped together, forming nonmotile aggregates which could account for the markedly reduced motility of the hosA mutant on swim plates at 30°C. We conclude that SlyA and HosA are independent transcriptional regulators that respond to different physicochemical cues to facilitate the environmental adaptation of E. coli.
机译：在肠致病性和肠出血性大肠杆菌（EPEC和EHEC）中，已确定SlyA家族的转录调节子家族中有两个成员是SlyA。对野生型以及相应的 hosA 和 slyA 缺失突变体的蛋白质印迹分析表明，SlyA和HosA是表达互不依赖的独特蛋白。在27个不同的 E中。检查的大肠杆菌菌株（EPEC，EHEC，肠侵袭性，肠聚集性，尿致病性和共性）中，有14个基因和蛋白质均为阳性。为了研究 hosA 表达，构建了 hosA :: luxCDABE 报告基因融合体。在 hosA 中， hosA 的表达显着降低，但在 slyA 突变体中却没有，并且受温度，盐和pH的影响。与SlyA相比，HosA没有激活神秘的 E。大肠杆菌K-12溶血素ClyA。 hosA 的突变不会影响III型分泌，LEE1和LEE4操纵子的调控，也不会影响E2348 / 69在肠上皮细胞上形成附着和脱落的病变的能力。然而，HosA参与了游泳板上运动的温度依赖性阳性控制，并调节 fliC 表达和FliC蛋白水平。在电泳迁移率迁移分析中，纯化的HosA蛋白与 fliC 启动子特异性结合，表明HosA直接调节鞭毛蛋白的表达。尽管直接检查在30°C的肉汤培养物中生长的鞭毛结构和单个 hosA 细胞的运动行为没有发现任何明显的差异，但 hosA 突变体与野生型不同聚在一起，形成不运动的聚集体，这可能解释了在30°C游泳板上 hosA 突变体的活力明显降低。我们得出的结论是，SlyA和HosA是独立的转录调节因子，它们对不同的理化线索作出响应，以促进Eem的环境适应。大肠杆菌。

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