Escherichia coli responds to environmental changes using enolasic degradosomes and stabilized DicF sRNA to alter cellular morphology
Escherichia coli responds to environmental changes using enolasic degradosomes and stabilized DicF sRNA to alter cellular morphology
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DOI：
10.1073/pnas.1703731114
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发表时间：
2017-09-19
影响因子：
11.1
通讯作者：
Lin-Chao, Sue
中科院分区：
文献类型：
--
作者：
Murashko, Oleg N.;Lin-Chao, Sue
大肠杆菌 RNase E 是一种必需酶，可形成称为“RNA 降解体”的多组分核糖核酸复合物。这些复合物由四个主要成分组成：RNase E、PNPase、RhlB RNA 解旋酶和烯醇化酶。然而，烯醇酶在 RNase E/降解体中的作用尚不清楚。在此，我们报告在厌氧条件下 RNase E/降解体中烯醇化酶的存在可调节细胞形态，导致大肠杆菌 MG1655 细胞成丝。在厌氧条件下，烯醇化酶与 RNase E/降解体结合，通过伴侣蛋白 Hfq 依赖性调节，稳定小 RNA (sRNA) DicF，即细胞分裂基因 ftsZ 的抑制剂。 RNase E/烯醇化酶分布从有氧条件下的膜相关模式转变为厌氧条件下的扩散模式。当烯醇酶-RNase E/降解体相互作用被破坏时，厌氧诱导的特性消失。我们提供了一种机制，通过调节 RNase E 亚细胞分布、RNase E 酶活性和丝状转变所需的 sRNA DicF 的稳定性，大肠杆菌利用烯醇酶结合的降解体从杆状转变为丝状形式，以响应厌氧情况。与大肠杆菌非致病性菌株相比，致病性大肠杆菌菌株的基因组中主要含有多个 sRNA DicF 拷贝，细胞丝状化先前被认为与细菌发病机制有关。我们的数据表明了厌氧条件下感染期间细菌细胞丝化的机制。
Escherichia coli RNase E is an essential enzyme that forms multicomponent ribonucleolytic complexes known as "RNA degradosomes." These complexes consist of four major components: RNase E, PNPase, RhlB RNA helicase, and enolase. However, the role of enolase in the RNase E/degradosome is not understood. Here, we report that presence of enolase in the RNase E/degradosome under anaerobic conditions regulates cell morphology, resulting in E. coli MG1655 cell filamentation. Under anaerobic conditions, enolase bound to the RNase E/degradosome stabilizes the small RNA (sRNA) DicF, i.e., the inhibitor of the cell division gene ftsZ, through chaperon protein Hfq-dependent regulation. RNase E/enolase distribution changes from membrane-associated patterns under aerobic to diffuse patterns under anaerobic conditions. When the enolase-RNase E/degradosome interaction is disrupted, the anaerobically induced characteristics disappear. We provide a mechanism by which E. coli uses enolase-bound degradosomes to switch from rod-shaped to filamentous form in response to anaerobiosis by regulating RNase E subcellular distribution, RNase E enzymatic activity, and the stability of the sRNA DicF required for the filamentous transition. In contrast to E. coli nonpathogenic strains, pathogenic E. coli strains predominantly have multiple copies of sRNA DicF in their genomes, with cell filamentation previously being linked to bacterial pathogenesis. Our data suggest a mechanism for bacterial cell filamentation during infection under anaerobic conditions.