Structural analysis of new local features in SECIS RNA hairpins
Structural analysis of new local features in SECIS RNA hairpins
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DOI：
10.1093/nar/28.14.2679
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发表时间：
2000-07-15
影响因子：
14.9
通讯作者：
Krol, A
中科院分区：
文献类型：
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作者：
Fagegaltier, D;Lescure, A;Krol, A
用于硒蛋白翻译的UGA硒代半胱氨酸密码子的解码需要SECIS元件，其是携带短或大顶端环的mRNA的3 '-UTR中的茎环基序。在以前的结构研究中，我们推导出一个二级结构模型SECIS RNA短顶端环。其他人的工作提出，顶端环内碱基配对可以发生在那些拥有大顶端环的SECIS中，产生2型SECIS与1型短环。在这项工作中，通过酶和/或化学探针分析了来自8种不同硒蛋白mRNA的SECIS元件，表明7种可以采用2型。此外，数据库搜索导致在果蝇和斑马鱼中发现硒磷酸合成酶2、1型脱碘酶和SelW mRNA中的SECIS元件，SECIS序列的比对不仅突出了形式2的优势，而且还使得有可能根据它们所属的硒蛋白mRNA的类型对SECIS元件进行分类。有趣的是，比对发现，一个未配对的腺嘌呤，以前被认为是不变的，是取代鸟嘌呤在四个SECIS元件。在体内测试，无论是A到G，也不是A到U的变化，在这个位置上大大影响的活动，而最有害的影响是由一个C，各种SECIS基序的功能和配体结合的假定贡献进行了讨论。
Decoding of the UGA selenocysteine codon for selenoprotein translation requires the SECIS element, a stem-loop motif in the 3'-UTR of the mRNA carrying short or large apical loops. In previous structural studies, we derived a secondary structure model for SECIS RNAs with short apical loops. Work from others proposed that intra-apical loop base pairing can occur in those SECIS that possess large apical loops, yielding form 2 SECIS versus the form 1 with short loops. In this work, SECIS elements arising from eight different selenoprotein mRNAs were assayed by enzymatic and/or chemical probing showing that seven can adopt form 2, Further, database searches led to the discovery in drosophila and zebrafish of SECIS elements in the selenophosphate synthetase 2, type 1 deiodinase and SelW mRNAs, Alignment of SECIS sequences not only highlighted the predominance of form 2 but also made it possible to classify the SECIS elements according to the type of selenoprotein mRNA they belong to. Interestingly, the alignment revealed that an unpaired adenine, previously thought to be invariant, is replaced by a guanine in four SECIS elements. Tested in vivo, neither the A to G nor the A to U changes at this position greatly affected the activity while the most detrimental effect was provided by a C, The putative contribution of the various SECIS motifs to function and ligand binding is discussed.