Characterization of MicA interactions suggests a potential novel means of gene regulation by small non-coding RNAs.
Characterization of MicA interactions suggests a potential novel means of gene regulation by small non-coding RNAs.
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DOI：
10.1093/nar/gkt008
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发表时间：
2013-03-01
影响因子：
14.9
通讯作者：
Callaghan AJ
中科院分区：
文献类型：
--
作者：
Henderson CA;Vincent HA;Stone CM;Phillips JO;Cary PD;Gowers DM;Callaghan AJ
MicA是一种小的非编码RNA，在大肠杆菌中调节ompA mRNA的翻译。MicA具有抑制功能，通过短序列的互补与靶mrna的翻译起始区碱基配对，阻断其核糖体结合位点。MicA结构包含两个茎环，这阻碍了其与目标mrna的相互作用，并且据认为，已知参与MicA调控ompA的RNA伴侣蛋白Hfq可能在结构上重塑MicA，以揭示同源配对的ompA结合位点。为了进一步表征这些相互作用，我们进行了生化和生物物理研究，使用天然云母和“稳定”版本，修改以模拟云母的构象状态，其中暴露了ompa结合位点。我们的数据证实了Hfq的两个作用：第一，使MicA和ompA接近，第二，重组MicA以允许暴露ompA结合位点进行配对，从而证明Hfq的RNA伴侣功能。此外，在累积的MicA水平下，我们发现了Mg2+依赖的自关联，该自关联阻断了ompa识别区域。我们讨论了Mg2+介导的MicA构象开关对MicA功能调节的潜在贡献。
MicA is a small non-coding RNA that regulates ompA mRNA translation in Escherichia coli. MicA has an inhibitory function, base pairing to the translation initiation region of target mRNAs through short sequences of complementarity, blocking their ribosome-binding sites. The MicA structure contains two stem loops, which impede its interaction with target mRNAs, and it is thought that the RNA chaperone protein Hfq, known to be involved in MicA regulation of ompA, may structurally remodel MicA to reveal the ompA-binding site for cognate pairing. To further characterize these interactions, we undertook biochemical and biophysical studies using native MicA and a ‘stabilized’ version, modified to mimic the conformational state of MicA where the ompA-binding site is exposed. Our data corroborate two proposed roles for Hfq: first, to bring both MicA and ompA into close proximity, and second, to restructure MicA to allow exposure of the ompA-binding site for pairing, thereby demonstrating the RNA chaperone function of Hfq. Additionally, at accumulated MicA levels, we identified a Mg2+-dependent self-association that occludes the ompA-recognition region. We discuss the potential contribution of an Mg2+-mediated conformational switch of MicA for the regulation of MicA function.
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影响因子：
15
作者：
Cayrol, Bastien;Nogues, Claude;Isambert, Herve
通讯作者：
Isambert, Herve
DOI：
10.1073/pnas.170281497
发表时间：
2000-08-29
影响因子：
11.1
作者：
Lease, RA;Belfort, M
通讯作者：
Belfort, M
影响因子：
6.1
作者：
Konarev, PV;Volkov, VV;Svergun, DI
通讯作者：
Svergun, DI
影响因子：
4.5
作者：
Moll, I;Afonyushkin, T;Bläsi, U
通讯作者：
Bläsi, U
影响因子：
10.5
作者：
Fender, Aurelie;Elf, Johan;Wagner, E. Gerhart H.
通讯作者：
Wagner, E. Gerhart H.