YmdB: a stress-responsive ribonuclease-binding regulator of E. coli RNase III activity
YmdB: a stress-responsive ribonuclease-binding regulator of E. coli RNase III activity
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DOI：
10.1101/gad.1729508
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发表时间：
2008-12-15
影响因子：
10.5
通讯作者：
Cohen, Stanley N.
中科院分区：
文献类型：
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作者：
Kim, Kwang-Sun;Manasherob, Robert;Cohen, Stanley N.
RNase III家族酶的广泛细胞作用包括原核生物和真核生物中的核糖体RNA（rRNA）加工、mRNA降解和非编码microRNA的产生。在这里，我们报告YmdB，进化保守的18.8 kDa的蛋白质大肠杆菌以前未知的功能，是RNase III裂解的调节剂。我们表明，YmdB的功能，通过与RNase III催化区的一个网站，YmdB的表达是转录激活的冷休克应激和进入静止期的细胞，这种激活需要σ因子编码基因，rpoS。我们发现，RNA酶III活性的下调发生在这两种压力，并依赖于YmdB生产过程中冷休克;相反，静止相调节是不受干扰的YmdB无效突变体细菌，表明存在额外的，YmdB独立的，动态调节RNA酶III的行动在正常细胞生长的因素。我们的研究结果揭示了核糖核酸酶结合蛋白在RNase III活性调节中的作用。
The broad cellular actions of RNase III family enzymes include ribosomal RNA ( rRNA) processing, mRNA decay, and the generation of noncoding microRNAs in both prokaryotes and eukaryotes. Here we report that YmdB, an evolutionarily conserved 18.8-kDa protein of Escherichia coli of previously unknown function, is a regulator of RNase III cleavages. We show that YmdB functions by interacting with a site in the RNase III catalytic region, that expression of YmdB is transcriptionally activated by both cold-shock stress and the entry of cells into stationary phase, and that this activation requires the sigma-factor-encoding gene, rpoS. We discovered that down-regulation of RNase III activity occurs during both stresses and is dependent on YmdB production during cold shock; in contrast, stationary-phase regulation was unperturbed in ymdB-null mutant bacteria, indicating the existence of additional, YmdB-independent, factors that dynamically regulate RNase III actions during normal cell growth. Our results reveal the previously unsuspected role of ribonuclease-binding proteins in the regulation of RNase III activity.