Translation of poly(A) tails leads to precise mRNA cleavage
Translation of poly(A) tails leads to precise mRNA cleavage
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DOI：
10.1261/rna.060418.116
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发表时间：
2017-05-01
期刊：
影响因子：
4.5
通讯作者：
Green, Rachel
中科院分区：
文献类型：
--
作者：
Guydosh, Nicholas R.;Green, Rachel
poly（A）尾的翻译导致mRNA切割，但这种“不间断/不进行”衰变过程的机制和全球普遍性尚不清楚。在这里，我们对短的15-18个核苷酸的mRNA足迹进行核糖体分析（在缺乏外泌体功能的酵母菌株中），以鉴定在mRNA衰变中间体的3'端停滞的核糖体。在这种背景下，我们发现mRNA切割延伸到核糖体上游数百个核苷酸，在poly（A）中停滞，并且主要在一个阅读框中。这些观察结果表明，衰变触发内切核酸裂解是密切相关的核糖体。令人惊讶的是，核糖体似乎积累（即，stall），尽管没有观察到显著的mRNA降解。然而，在过早的多聚腺苷酸化（编码多聚赖氨酸）的位点发现了内切核酸裂解，并且在这些位点停滞的核糖体的拯救依赖于Dom 34。这些结果表明，当多聚腺苷酸化位点在发育、肿瘤发生过程中发生变化时，或当翻译终止/再循环受损时，这一过程可能是至关重要的。
Translation of poly(A) tails leads to mRNA cleavage but the mechanism and global pervasiveness of this "nonstop/no-go" decay process is not understood. Here we performed ribosome profiling (in a yeast strain lacking exosome function) of short 15-18 nucleotides mRNA footprints to identify ribosomes stalled at 3' ends of mRNA decay intermediates. In this background, we found mRNA cleavage extending hundreds of nucleotides upstream of ribosome stalling in poly(A) and predominantly in one reading frame. These observations suggest that decay-triggering endonucleolytic cleavage is closely associated with the ribosome. Surprisingly, ribosomes appeared to accumulate (i.e., stall) in the transcriptome when as few as three consecutive ORF-internal lysine codons were positioned in the A, P, and E sites though significant mRNA degradation was not observed. Endonucleolytic cleavage was found, however, at sites of premature polyadenylation (encoding polylysine) and rescue of the ribosomes stalled at these sites was dependent on Dom34. These results suggest this process may be critical when changes in the polyadenylation site occur during development, tumorigenesis, or when translation termination/recycling is impaired.