Ribosome stalling during translation elongation induces cleavage of mRNA being translated in Escherichia coli
Ribosome stalling during translation elongation induces cleavage of mRNA being translated in Escherichia coli
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DOI：
10.1074/jbc.m312805200
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发表时间：
2004-04-09
影响因子：
4.8
通讯作者：
Aiba, H
中科院分区：
文献类型：
--
作者：
Sunohara, T;Jojima, K;Aiba, H
最近发现，某些新生肽引起的核糖体在终止密码子处暂停会诱导大肠杆菌细胞中 mRNA 的裂解 (1,2)。我们在本研究中解决的问题是当翻译延伸被阻止时是否会发生 mRNA 切割。我们重点关注源自 SecM 的特定肽序列 (AS17)，已知该序列会导致伸长停滞。当编码CRP-AS17-IIA(Glc)的crp-crr融合基因表达时，有效地产生在阻滞序列周围截短的cAMP受体蛋白(CRP)，并且它们被转移信使RNA(tmRNA)系统标记。 Northern 印迹分析显示，生成了截短的上游 crp 和下游 crr mRNA，同时全长 crp-crr mRNA 的量减少。在 tmRNA 存在的情况下，由于快速降解，截短的 crp mRNA 显着减少。截短的 crp mRNA 的 3' 末端与截短的 CRP 蛋白的 C 末端很好地对应。我们得出的结论是，由阻滞序列引起的核糖体停滞会诱导阻滞点附近的 mRNA 裂解，从而产生可被 tmRNA 识别的不间断 mRNA。我们提出，核糖体停滞诱导的 mRNA 裂解与 tmRNA 系统协同作用，作为确保蛋白质合成质量控制并可能调节某些基因表达的一种方式。
Recently, it has been found that ribosome pausing at stop codons caused by certain nascent peptides induces cleavage of mRNA in Escherichia coli cells (1,2). The question we addressed in the present study is whether mRNA cleavage occurs when translation elongation is prevented. We focused on a specific peptide sequence (AS17), derived from SecM, that is known to cause elongation arrest. When the crp-crr fusion gene encoding CRP-AS17-IIA(Glc) was expressed, cAMP receptor protein (CRP) proteins truncated around the arrest sequence were efficiently produced, and they were tagged by the transfer-messenger RNA (tmRNA) system. Northern blot analysis revealed that both truncated upstream crp and downstream crr mRNAs were generated along with reduced amounts of the full-length crp-crr mRNA. The truncated crp mRNA dramatically decreased in the presence of tmRNA due to rapid degradation. The 3' ends of truncated crp mRNA correspond well to the C termini of the truncated CRP proteins. We conclude that ribosome stalling by the arrest sequence induces mRNA cleavage near the arrest point, resulting in nonstop mRNAs that are recognized by tmRNA. We propose that the mRNA cleavage induced by ribosome stalling acts in concert with the tmRNA system as a way to ensure quality control of protein synthesis and possibly to regulate the expression of certain genes.