The Transfer-Messenger RNA-Small Protein B System Plays a Role in Avian Pathogenic Escherichia coli Pathogenicity
The Transfer-Messenger RNA-Small Protein B System Plays a Role in Avian Pathogenic Escherichia coli Pathogenicity
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转移信使RNA-小蛋白B系统在禽致病性大肠杆菌致病性中发挥作用
DOI：
10.1128/jb.00628-13
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发表时间：
2013-11-01
影响因子：
3.2
通讯作者：
Liu, Xiufan
中科院分区：
文献类型：
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作者：
Mu, Xiaohui;Huan, Haixia;Liu, Xiufan
摘要肠外致病性大肠杆菌（ExPEC）能够在肠道外定植并发展为全身性感染。禽致病性E.大肠杆菌（APEC）是ExPEC组的成员，并且引起禽大肠杆菌病。转移mRNA-小蛋白B（transfer-mRNA-small protein B，tmRNA-SmpB）介导的转译是一种细菌翻译调控系统，它指导蛋白质的修饰和降解，使生物合成停滞或中断的蛋白质能够拯救缺失终止密码子的缺陷mRNA的3′端停滞的核糖体。我们发现，破坏一个，或两个，smpB或ssrA基因显着降低了APEC菌株E058的毒力，鸡感染试验评估。此外，在定殖和持久性测定中，突变体明显减弱。实时荧光定量RT-PCR分析结果表明，转录调控基因rfaH和毒力基因kpsM、chuA、iss的转录水平均较野生型菌株显著降低。巨噬细胞感染试验表明，突变株降低了复制和/或生存能力的巨噬细胞HD 11细胞系相比，亲本菌株，E058。然而，没有显着差异，观察到的巨噬细胞的摄入和鸡血清中的电阻之间的突变体和野生型菌株。这些数据表明tmRNA-SmpB系统在APEC O2菌株E058的发病机制中是重要的。
ABSTRACT Extraintestinal pathogenic Escherichia coli (ExPEC) is capable of colonizing outside of the intestinal tract and evolving into a systemic infection. Avian pathogenic E. coli (APEC) is a member of the ExPEC group and causes avian colibacillosis. Transfer-mRNA-small protein B (tmRNA-SmpB)-mediated trans-translation is a bacterial translational control system that directs the modification and degradation of proteins, the biosynthesis of which has stalled or has been interrupted, facilitating the rescue of ribosomes stalled at the 3′ ends of defective mRNAs that lack a stop codon. We found that disruption of one, or both, of the smpB or ssrA genes significantly decreased the virulence of the APEC strain E058, as assessed by chicken infection assays. Furthermore, the mutants were obviously attenuated in colonization and persistence assays. The results of quantitative real-time reverse transcription-PCR analysis indicated that the transcription levels of the transcriptional regulation gene rfaH and the virulence genes kpsM, chuA, and iss were significantly decreased compared to those of the wild-type strain. Macrophage infection assays showed that the mutant strains reduced the replication and/or survival ability in the macrophage HD11 cell line compared to that of the parent strain, E058. However, no significant differences were observed in ingestion by macrophages and in chicken serum resistance between the mutant and the wild-type strains. These data indicate that the tmRNA-SmpB system is important in the pathogenesis of APEC O2 strain E058.