Quorum sensing is a global regulatory mechanism in enterohemorrhagic Escherichia coli O157:H7
Quorum sensing is a global regulatory mechanism in enterohemorrhagic Escherichia coli O157:H7
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DOI：
10.1128/jb.183.17.5187-5197.2001
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发表时间：
2001-09-01
影响因子：
3.2
通讯作者：
Kaper, JB
中科院分区：
文献类型：
--
作者：
Sperandio, V;Torres, AG;Kaper, JB
肠出血性大肠杆菌（EHEC）O 157：H7是许多国家爆发出血性腹泻和溶血性尿毒症综合征的原因。肠出血性大肠杆菌的毒力机制包括产生滋贺毒素（Stx）和在肠上皮细胞上形成附着和消退（AE）损伤。我们最近报道了参与AE损伤形成的基因通过自诱导物-2（autoinducer-2）受到群体感应的调节，所述自诱导物-2由luxS基因的产物合成。在这项研究中，我们杂交E。大肠杆菌基因芯片，从EHEC 86-24株及其同基因luxS突变株中提取RNA合成cDNA。我们观察到404个基因被luxS调控至少5倍，约占阵列基因的10%;与luxS突变体相比，野生型菌株中有235个基因上调，169个基因下调。下调的基因包括几个参与细胞分裂的基因，以及核糖体和tRNA基因。与这种基因表达模式一致，luxS突变体比野生型菌株生长得更快（在Dulbecco改良的Eagle培养基中，世代时间分别为37.5和60分钟）。上调的基因包括几个参与鞭毛的表达和组装，运动性和趋化性。使用操纵子：：lacZ融合到I，II和III类鞭毛基因，我们能够确认这种转录调控。我们还观察到较少的鞭毛蛋白质印迹和电子显微镜和减少运动晕在半固体琼脂中的luxS突变体。野生型菌株和luxS突变体的平均游泳速度分别为12.5和6.6 μ m/s。我们还观察到由于群体感应，Stx的产生增加。编码Stx的基因与λ-样噬菌体基因一起沿着转录，由SOS应答诱导，参与SOS应答的基因也受群体感应调节.这些结果表明群体感应是大肠杆菌基本生理功能的一种全局调节机制。大肠杆菌以及毒力因子。
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for outbreaks of bloody diarrhea and hemolytic-uremic syndrome in many countries. EHEC virulence mechanisms include the production of Shiga toxins (Stx) and formation of attaching and effacing (AE) lesions on intestinal epithelial cells. We recently reported that genes involved in the formation of the AE lesion were regulated by quorum sensing through autoinducer-2, which is synthesized by the product of the luxS gene. In this study we hybridized an E. coli gene array with cDNA synthesized from RNA that was extracted from EHEC strain 86-24 and its isogenic luxS mutant. We observed that 404 genes were regulated by luxS at least fivefold, which comprises approximately 10% of the array genes; 235 of these genes were up-regulated and 169 were down-regulated in the wild-type strain compared to in the luxS mutant. Down-regulated genes included several involved in cell division, as well as ribosomal and tRNA genes. Consistent with this pattern of gene expression, the luxS mutant grows faster than the wild-type strain (generation times of 37.5 and 60 min, respectively, in Dulbecco modified Eagle medium). Up-regulated genes included several involved in the expression and assembly of flagella, motility, and chemotaxis. Using operon::lacZ fusions to class I, II, and III flagellar genes, we were able to confirm this transcriptional regulation. We also observed fewer flagella by Western blotting and electron microscopy and decreased motility halos in semisolid agar in the luxS mutant. The average swimming speeds for the wild-type strain and the luxS mutant are 12.5 and 6.6 mum/s, respectively. We also observed an increase in the production of Stx due to quorum sensing. Genes encoding Stx, which are transcribed along with lambda -like phage genes, are induced by an SOS response, and genes involved in the SOS response were also regulated by quorum sensing. These results indicate that quorum sensing is a global regulatory mechanism for basic physiological functions of E. coli as well as for virulence factors.