The key protein of endosomal mRNP transport Rrm4 binds translational landmark sites of cargo mRNAs
The key protein of endosomal mRNP transport Rrm4 binds translational landmark sites of cargo mRNAs
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DOI：
10.15252/embr.201846588
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发表时间：
2019-01-01
期刊：
影响因子：
7.7
通讯作者：
Zarnack, Kathi
中科院分区：
文献类型：
--
作者：
Olgeiser, Lilli;Haag, Carl;Zarnack, Kathi
RNA结合蛋白（RBP）通过介导货物mRNA的主动转运和局部翻译来决定时空基因表达。在这里，我们投在转录组范围内的观点，转运mRNA和同源RBP结合位点的内体信使核糖核蛋白（mRNP）运输玉米黑粉菌。使用单个核苷酸分辨率UV交联和免疫沉淀（iCLIP），我们比较了关键的转运RBP Rrm4和新鉴定的内体mRNP组分Grp1，这对协调菌丝生长至关重要。两种RBP主要结合在数千个共享货物mRNA的3个非翻译区中，通常非常接近。有趣的是，Rrm4精确地结合在终止密码子上，终止密码子构成了翻译的标志性位点，这表明mRNA转运和翻译的密切联系。为了揭示识别的密码，我们确定UAUG是Rrm4的特异性结合基序，其与第三个RRM结构域结合。总而言之，我们提供了第一个见解的位置组织的共同定位的RBP对个别货物mRNA。
RNA-binding proteins (RBPs) determine spatiotemporal gene expression by mediating active transport and local translation of cargo mRNAs. Here, we cast a transcriptome-wide view on the transported mRNAs and cognate RBP binding sites during endosomal messenger ribonucleoprotein (mRNP) transport in Ustilago maydis. Using individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP), we compare the key transport RBP Rrm4 and the newly identified endosomal mRNP component Grp1 that is crucial to coordinate hyphal growth. Both RBPs bind predominantly in the 3 untranslated region of thousands of shared cargo mRNAs, often in close proximity. Intriguingly, Rrm4 precisely binds at stop codons, which constitute landmark sites of translation, suggesting an intimate connection of mRNA transport and translation. Towards uncovering the code of recognition, we identify UAUG as specific binding motif of Rrm4 that is bound by its third RRM domain. Altogether, we provide first insights into the positional organisation of co-localising RBPs on individual cargo mRNAs.