A Role for REP Sequences in Regulating Translation

作者：Liang Wenxing; Rudd Kenneth E; Deutscher Murray P^*

来源：Molecular Cell, 2015, 58(3): 431-439.

DOI：10.1016/j.molcel.2015.03.019

Repetitive extragenic palindromic (REP) sequences are highly structured elements found downstream of similar to 500 genes in Escherichia coli that result in extensive stem-loop structures in their mRNAs. However, their physiological role has remained elusive. Here, we show that REP sequences can downregulate translation, but only if they are within 15 nt of a termination codon; a spacing of 16 nt has no effect, suggesting that the REP element acts to stall ribosome movement. Ribosome stalling leads to cleavage of the mRNA and induction of the trans-translation process. Using nrdAB as a model, we find that its regulation can be partially reversed by overexpression of RNA helicases and can be fully overcome upon UV stress, emphasizing the importance of this regulatory process. Since 50% of REP-associated genes have these elements within the critical 15 nt, these findings identify a regulatory mechanism with the potential to affect translation from a large number of genes.

• 出版日期2015-5-7
• 单位青岛农业大学