Antisense RNA regulation in prokaryotes: Rapid RNA/RNA interaction facilitated by a general U-turn loop structure
Antisense RNA regulation in prokaryotes: Rapid RNA/RNA interaction facilitated by a general U-turn loop structure
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DOI：
10.1006/jmbi.1999.3306
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发表时间：
1999-12-17
影响因子：
5.6
通讯作者：
Gerdes, K
中科院分区：
文献类型：
--
作者：
Franch, T;Petersen, M;Gerdes, K
反义RNA的有效基因调控需要与同源靶RNA的快速双分子相互作用。对比分析发现，在反义RNA调控的基因系统中，一个YUNR基序（Y =嘧啶，R =嘌呤）在RNA识别环中普遍存在。(Y)UNR序列基序在trna、锤头核酶和其他保守RNA环的许多反密码子环和所有t环中指定两个环内氢键形成u型结构。这种结构在RNA磷酸盐主链中产生一个尖锐的弯曲，并在溶剂暴露的堆叠结构中呈现以下三到四个碱基，为与互补RNA的快速相互作用提供了一个支架。来自质粒R1的Sok反义RNA通过阻止mok Shine & Dalgarno元件的核糖体进入抑制hok mRNA的翻译。Sok-RNA的5'单链区域识别hok mRNA中的环。我们在这里表明，Sok反义RNA与其在hok mRNA中的靶标之间的初始配对发生在观察到的二阶速率常数为2 × 10(6) M-1 s（-1）。消除hok mRNA靶环中YUNR基序的突变导致反义RNA配对动力学降低，而维持YUNR基序的突变则沉默。此外，乙基亚硝基脲探测到的RNA磷酸盐骨架可达性与YUNR基序促进的u型结构形成一致。由于YUNR U-turn基序存在于许多反义/靶对的识别单元中，因此该基序可能是RNA配对率的常用增强子。这一结论与对ColE1的RNAI/RNAII、R1的CopA/CopT和IS10的RNA-IN/RNA-OUT等几个反义控制系统突变分析的重新解释是一致的。(C) 1999学术出版社。
Efficient gene control by antisense RNA requires rapid bi-molecular interaction with a cognate target RNA. A comparative analysis revealed that a YUNR motif (Y = pyrimidine, R = purine) is ubiquitous in RNA recognition loops in antisense RNA-regulated gene systems. The (Y)UNR sequence motif specifies two intraloop hydrogen bonds forming U-turn structures in many anticodon-loops and all T-loops of tRNAs, the hammerhead ribozyme and in other conserved RNA loops. This structure creates a sharp bend in the RNA phosphate-backbone and presents the following three to four bases in a solvent-exposed, stacked configuration providing a scaffold for rapid interaction with complementary RNA. Sok antisense RNA from plasmid R1 inhibits translation of the hok mRNA by preventing ribosome entry at the mok Shine & Dalgarno element. The 5' single-stranded region of Sok-RNA recognizes a loop in the hok mRNA. We show here, that the initial pairing between Sok antisense RNA and its target in hok mRNA occurs with an observed second-order rate-constant of 2 x 10(6) M-1 s(-1). Mutations that eliminate the YUNR motif in the target loop of hok mRNA resulted in reduced antisense RNA pairing kinetics, whereas mutations maintaining the YUNR motif were silent. In addition, RNA phosphate-backbone accessibility probing by ethylnitrosourea was consistent with a U-turn structure formation promoted by the YUNR motif. Since the YUNR U-turn motif is present in the recognition units of many antisense/target pairs, the motif is likely to be a generally employed enhancer of RNA pairing rates. This suggestion is consistent with the re-interpretation of the mutational analyses of several antisense control systems including RNAI/RNAII of ColE1, CopA/CopT of R1 and RNA-IN/RNA-OUT of IS10. (C) 1999 Academic Press.