A minimal base-pairing region of a bacterial small RNA SgrS required for translational repression of ptsG mRNA
A minimal base-pairing region of a bacterial small RNA SgrS required for translational repression of ptsG mRNA
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DOI：
10.1111/j.1365-2958.2010.07141.x
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发表时间：
2010-05-01
影响因子：
3.6
通讯作者：
Aiba, Hiroji
中科院分区：
文献类型：
--
作者：
Maki, Kimika;Morita, Teppei;Aiba, Hiroji
大肠杆菌SgrS是一种Hfq结合的小RNA，在葡萄糖-磷酸盐胁迫下被诱导引起翻译抑制和编码主要葡萄糖转运蛋白的ptsG mRNA的RNase E依赖性快速降解。SgrS的3'端有一段31 nt长的片段与ptsG mRNA的翻译起始区部分互补。我们先前表明，SgrS单独导致翻译抑制时，预退火与ptsG mRNA的高温处理在体外。在这里，我们研究了在体外合成的RNA寡核苷酸（oligos）的ptsG mRNA的翻译抑制，以确定翻译抑制所需的SgrS区域。我们首先证明，对应于碱基配对区域的31 nt RNA寡核苷酸足以抑制ptsG mRNA的翻译。然后，我们表明RNA oligo可以缩短到14 nt而不失去其作用。有证据表明，14 nt碱基配对区域足以抑制ptsG翻译的情况下，全长SgrS在体内。我们的结论是，SgrS 168-181是一个最小的碱基配对区域的翻译抑制ptsG mRNA。有趣的是，14 nt oligo在没有高温预处理的情况下有效地抑制ptsG翻译，这表明结构化SgrS的重塑是Hfq促进碱基配对的重要机制。
P>Escherichia coli SgrS is an Hfq-binding small RNA that is induced under glucose-phosphate stress to cause translational repression and RNase E-dependent rapid degradation of ptsG mRNA encoding the major glucose transporter. A 31-nt-long stretch in the 3' region of SgrS is partially complementary to the translation initiation region of ptsG mRNA. We showed previously that SgrS alone causes translational repression when pre-annealed with ptsG mRNA by a high-temperature treatment in vitro. Here, we studied translational repression of ptsG mRNA in vitro by synthetic RNA oligonucleotides (oligos) to define the SgrS region required for translational repression. We first demonstrate that a 31 nt RNA oligo corresponding to the base-pairing region is sufficient for translational inhibition of ptsG mRNA. Then, we show that RNA oligo can be shortened to 14 nt without losing its effect. Evidence shows that the 14 nt base-pairing region is sufficient to inhibit ptsG translation in the context of full-length SgrS in vivo. We conclude that SgrS 168-181 is a minimal base-pairing region for translational inhibition of ptsG mRNA. Interestingly, the 14 nt oligo efficiently inhibited ptsG translation without the high-temperature pre-treatment, suggesting that remodelling of structured SgrS is an important mechanism by which Hfq promotes the base pairing.