Enolase in the RNA degradosome plays a crucial role in the rapid decay of glucose transporter mRNA in the response to phosphosugar stress in Escherichia coli
Enolase in the RNA degradosome plays a crucial role in the rapid decay of glucose transporter mRNA in the response to phosphosugar stress in Escherichia coli
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DOI：
10.1111/j.1365-2958.2004.04329.x
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发表时间：
2004-11-01
影响因子：
3.6
通讯作者：
Aiba, H
中科院分区：
文献类型：
--
作者：
Morita, T;Kawamoto, H;Aiba, H
在大肠杆菌中，当糖酵解途径在其早期步骤被阻断时，编码主要葡萄糖转运蛋白的ptsG mRNA响应于葡萄糖6-P或果糖6-P的积累而以RNase E依赖性方式快速降解。RNA酶E是一种主要的核酸内切酶，与多核苷酸磷酸化酶（PNIPE）、RhlB解旋酶和糖酵解酶烯醇化酶结合，其结合到其C-末端支架区域以形成称为RNA降解体的多酶复合物。烯醇化酶在基于RNase E的降解体中的作用在RNA衰变中一直是完全神秘的。在这篇文章中，我们证明了去除RNase E的支架区域抑制ptsG mRNA的快速降解，而不影响正常条件下ptsG mRNA的表达。我们还表明，烯醇化酶的耗尽，但不是破坏的pnp或rhlB消除ptsG mRNA的快速降解。两者合计，我们得出结论，降解体内的烯醇化酶起着至关重要的作用，在调节ptsG mRNA的稳定性，响应于代谢应激。这是第一个例子中，烯醇化酶在RNA降解体的生理作用已被证明。此外，我们表明，PNIPs和RhlB内的degradosome合作，以消除短的降解中间产物的ptsG mRNA。
The ptsG mRNA encoding the major glucose transporter is rapidly degraded in an RNase E-dependent manner in response to the accumulation of glucose 6-P or fructose 6-P when the glycolytic pathway is blocked at its early steps in Escherichia coli. RNase E, a major endonuclease, is associated with polynucleotide phosphorylase (PNPase), RhlB helicase and a glycolytic enzyme, enolase, which bind to its C-terminal scaffold region to form a multienzyme complex called the RNA degradosome. The role of enolase within the RNase E-based degradosome in RNA decay has been totally mysterious. In this article, we demonstrate that the removal of the scaffold region of RNase E suppresses the rapid degradation of ptsG mRNA in response to the metabolic stress without affecting the expression of ptsG mRNA under normal conditions. We also demonstrate that the depletion of enolase but not the disruption of pnp or rhlB eliminates the rapid degradation of ptsG mRNA. Taken together, we conclude that enolase within the degradosome plays a crucial role in the regulation of ptsG mRNA stability in response to a metabolic stress. This is the first instance in which a physiological role for enolase in the RNA degradosome has been demonstrated. In addition, we show that PNPase and RhlB within the degradosome cooperate to eliminate short degradation intermediates of ptsG mRNA.