Ribosomes inhibit an RNase E cleavage which induces the decay of the rpsO mRNA of Escherichia coli
Ribosomes inhibit an RNase E cleavage which induces the decay of the rpsO mRNA of Escherichia coli
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DOI：
10.1093/emboj/17.16.4790
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发表时间：
1998-08-17
期刊：
影响因子：
11.4
通讯作者：
Régnier, P
中科院分区：
文献类型：
--
作者：
Braun, F;Le Derout, J;Régnier, P
通常提出的解释翻译对许多细菌mRNAs稳定作用的假设是，核糖体掩盖了控制mRNA衰减率的内切核糖核酸酶位点。我们首次证明了核糖体干扰了导致mRNA衰退的特定RNase E处理事件，这些实验使用了翻译操作符缺失的rpsO mRNA，其中核糖体蛋白S15自动调节其合成。我们证明核糖体抑制RNase E的切割，rpsO编码序列下游的10个核苷酸，负责触发由多核苷酸磷酸化酶介导的信息的胞外降解。早期终止密码子和插入增加了UAA终止密码子和这个RNase E位点之间的无核糖体mRNA的长度，破坏了翻译的mRNA的稳定性，促进了RNase E的切割，这表明核糖体立体地抑制RNase E进入加工位点。因此，缩短这两个位点之间距离的突变可以稳定mRNA，此外，一项实验表明，当插入到翻译后的mRNA的编码序列中时，10个核苷酸的插入破坏了未翻译的mRNA的稳定性，并不影响mRNA的稳定性，这表明核糖体可以掩盖加工位点上游10-20个核苷酸的RNA特征，这有助于RNase E的切割效率。
The hypothesis generally proposed to explain the stabilizing effect of translation on many bacterial mRNAs is that ribosomes mask endoribonuclease sites which control the mRNA decay rate. We present the first demonstration that ribosomes interfere with a particular RNase E processing event responsible for mRNA decay, These experiments used an rpsO mRNA deleted of the translational operator where ribosomal protein S15 autoregulates its synthesis. We demonstrate that ribosomes inhibit the RNase E cleavage, 10 nucleotides downstream of the rpsO coding sequence, responsible for triggering the exonucleolytic decay of the message mediated by polynucleotide phosphorylase. Early termination codons and insertions which increase the length of ribosome-free mRNA between the UAA termination codon and this RNase E site destabilize the translated mRNA and facilitate RNase E cleavage, suggesting that ribosomes sterically inhibit RNase E access to the processing site. Accordingly, a mutation which reduces the distance between these two sites stabilizes the mRNA, Moreover, an experiment showing that a 10 nucleotide insertion which destabilizes the untranslated mRNA does not affect mRNA stability when it is inserted in the coding sequence of a translated mRNA demonstrates that ribosomes can mask an RNA feature, 10-20 nucleotides upstream of the processing site, which contributes to the RNase E cleavage efficiency.