fhlA repression by OxyS RNA:: Kissing complex formation at two sites results in a stable antisense-target RNA complex
fhlA repression by OxyS RNA:: Kissing complex formation at two sites results in a stable antisense-target RNA complex
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DOI：
10.1006/jmbi.2000.3942
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发表时间：
2000-07-28
影响因子：
5.6
通讯作者：
Altuvia, S
中科院分区：
文献类型：
--
作者：
Argaman, L;Altuvia, S
OxyS是一种小的未翻译RNA，在大肠杆菌氧化应激反应中被诱导。这种小RNA作为影响多个基因表达的全局调节剂。OxyS抑制fhlA的翻译，fhlA是甲酸代谢的转录激活因子。在此之前，我们已经证明OxyS对fhlA的抑制是通过碱基配对介导的，其短序列重叠在核糖体结合位点上。在这里，我们发现OxyS-fhlA相互作用涉及位于fhlA编码区下游的第二个位点。破坏该位点配对的突变会影响OxyS阻止30s核糖体与fhlA mRNA结合的能力。fhlA mRNA的结构探测表明，这两个位点位于两个茎环结构的环中。OxyS-fhlA配对分析表明，OxyS与野生型fhlA结合的表观解离常数为25 nM，表明OxyS与fhlA之间形成了稳定的反义靶复合物。任何一个位点的突变都会破坏OxyS与fhlA的配对，从而降低该复合物的稳定性。我们的研究结果表明，接吻复合物的形成足以抑制OxyS对fhlA的翻译。(C) 2000年学术出版社。
OxyS is a small untranslated RNA that is induced in response to oxidative stress in Escherichia coli. This small RNA acts as a global regulator affecting the expression of multiple genes. OxyS represses the translation of fhlA, a transcriptional activator for formate metabolism. Previously, we have shown that fhlA repression by OxyS is mediated through base-pairing with a short sequence overlapping the ribosome binding site. Here we show that the OxyS-fhlA interaction involves a second site residing further downstream, within the coding region of fhlA. Mutations that disrupt pairing at this site affect the ability of OxyS to prevent 30 S ribosomes from binding to fhlA mRNA. Structure probing of fhlA mRNA demonstrates that both sites reside in the loops of two stem-loop structures. OxyS-fhlA pairing analysis shows that OxyS binds wild-type fhlA with an apparent dissociation constant of 25 nM, indicating that kissing complex formation between OxyS and fhlA results in a stable antisense-target complex. Mutations at either site, which disrupt pairing of OxyS to fhlA, decrease the stability of this complex. Our results indicate that kissing complex formation is sufficient to repress fhlA translation by OxyS. (C) 2000 Academic Press.