Model Uracil-Rich RNAs and Membrane Protein mRNAs Interact Specifically with Cold Shock Proteins in Escherichia coli.
Model Uracil-Rich RNAs and Membrane Protein mRNAs Interact Specifically with Cold Shock Proteins in Escherichia coli.
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DOI：
10.1371/journal.pone.0134413
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Bibi E
中科院分区：
文献类型：
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作者：
Benhalevy D;Bochkareva ES;Biran I;Bibi E
编码完整膜蛋白的mRNAs（MPR）与编码胞质mRNAs（CPR）的mRNAs不同吗？这是暗示从新兴的概念，MPR被特异性地识别，并交付到膜结合的核糖体在一个不依赖于免疫抑制的方式。MPR可能通过编码疏水跨膜螺旋的富含尿嘧啶的片段被识别。为了研究这一假设，我们设计了DNA序列编码模型不可翻译的转录本，模仿MPR或CPR。通过利用体外合成的生物素化RNA与大肠杆菌提取物混合，我们鉴定了模拟MPR的转录本与通常在生理条件下表达的冷休克蛋白CspE和CspC之间发生的高度特异性相互作用。与E.大肠杆菌表达6His标记的CspE或CspC证实，在体内不仅发生与富含尿嘧啶的模型不可翻译转录物的特异性相互作用，而且还与内源性MPR发生特异性相互作用。我们的研究结果表明，进化上保守的冷休克蛋白可能有一个角色，可能是滥交伴侣，在MPR的生物发生。
Are integral membrane protein-encoding mRNAs (MPRs) different from other mRNAs such as those encoding cytosolic mRNAs (CPRs)? This is implied from the emerging concept that MPRs are specifically recognized and delivered to membrane-bound ribosomes in a translation-independent manner. MPRs might be recognized through uracil-rich segments that encode hydrophobic transmembrane helices. To investigate this hypothesis, we designed DNA sequences encoding model untranslatable transcripts that mimic MPRs or CPRs. By utilizing in vitro-synthesized biotinylated RNAs mixed with Escherichia coli extracts, we identified a highly specific interaction that takes place between transcripts that mimic MPRs and the cold shock proteins CspE and CspC, which are normally expressed under physiological conditions. Co-purification studies with E. coli expressing 6His-tagged CspE or CspC confirmed that the specific interaction occurs in vivo not only with the model uracil-rich untranslatable transcripts but also with endogenous MPRs. Our results suggest that the evolutionarily conserved cold shock proteins may have a role, possibly as promiscuous chaperons, in the biogenesis of MPRs.