Protein-mediated protection as the predominant mechanism for defining processed mRNA termini in land plant chloroplasts.
Protein-mediated protection as the predominant mechanism for defining processed mRNA termini in land plant chloroplasts.
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DOI：
10.1093/nar/gkr1137
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发表时间：
2012-04
影响因子：
14.9
通讯作者：
Barkan A
中科院分区：
文献类型：
--
作者：
Zhelyazkova P;Hammani K;Rojas M;Voelker R;Vargas-Suárez M;Börner T;Barkan A
大多数叶绿体mRNA是由较大的前体加工而成的。已经提出了几种机制来介导这些加工事件，包括位点特异性切割和RNA结构对核酸外切酶的停滞。基于对五肽重复序列（PPR）蛋白PPR 10的分析，提出了一种蛋白质屏障机制：PPR 10结合两个顺反子间区域，阻碍5′-和3′-外切核酸酶，导致PPR 10结合在5′-或3′-末端的加工RNA。在这项研究中，我们提供的证据表明，蛋白质屏障是确定加工mRNA末端在叶绿体中的主要手段。首先，我们绘制了额外的RNA末端，其排列表明通过PPR 10样机制的生物发生。其次，我们发现PPR蛋白HCF 152与需要HCF 152积累的转录本的5′或3′末端结合，这为HCF 152通过阻断核酸外切酶来定义RNA末端提供了证据。最后，我们建立在观察PPR 10和HCF 152结合位点积累为小叶绿体RNA推断其他PPR蛋白的结合位点。我们发现，大多数加工mRNA末端的小RNA的序列是高度保守的。我们认为，每个这样的小RNA是一个PPR样蛋白的足迹，保护相邻的RNA降解。
Most chloroplast mRNAs are processed from larger precursors. Several mechanisms have been proposed to mediate these processing events, including site-specific cleavage and the stalling of exonucleases by RNA structures. A protein barrier mechanism was proposed based on analysis of the pentatricopeptide repeat (PPR) protein PPR10: PPR10 binds two intercistronic regions and impedes 5′- and 3′-exonucleases, resulting in processed RNAs with PPR10 bound at the 5′- or 3′-end. In this study, we provide evidence that protein barriers are the predominant means for defining processed mRNA termini in chloroplasts. First, we map additional RNA termini whose arrangement suggests biogenesis via a PPR10-like mechanism. Second, we show that the PPR protein HCF152 binds to the immediate 5′- or 3′-termini of transcripts that require HCF152 for their accumulation, providing evidence that HCF152 defines RNA termini by blocking exonucleases. Finally, we build on the observation that the PPR10 and HCF152 binding sites accumulate as small chloroplast RNAs to infer binding sites of other PPR proteins. We show that most processed mRNA termini are represented by small RNAs whose sequences are highly conserved. We suggest that each such small RNA is the footprint of a PPR-like protein that protects the adjacent RNA from degradation.
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影响因子：
14.9
作者：
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通讯作者：
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影响因子：
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CSRDB：用于谷物的小型RNA集成数据库和浏览器资源。
影响因子：
14.9
作者：
Johnson, Cameron;Bowman, Lewis;Adai, Alex T;Vance, Vicki;Sundaresan, Venkatesan
通讯作者：
Sundaresan, Venkatesan