In vivo selection of RNAs that localize in the nucleus
In vivo selection of RNAs that localize in the nucleus
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DOI：
10.1093/emboj/16.4.793
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发表时间：
1997-02-17
期刊：
影响因子：
11.4
通讯作者：
Dahlberg, JE
中科院分区：
文献类型：
--
作者：
Grimm, C;Lund, E;Dahlberg, JE
RNA的核定位受到顺式作用元件（NLE）的影响，顺式作用元件导致核输入或保留或阻断从核输出。为了确定这样的元素，我们选择和分析转录本，位于非洲爪蟾卵母细胞的细胞核。从m（7）G-加帽RNA的集合中分离RNA，其中插入了序列的组合文库（n = 20）。一类选择的RNA（Sm+）有一个共同的Sm结合位点（AAUUUUUGG）和细胞质中的结合Sm蛋白，这些RNA类似于小核RNA，如U1和U 5 RNA，在其双向核质运输和其5 '-帽超甲基化。另一类是Sm-RNA，含有掩蔽RNA的m（7）G帽并促进与La蛋白相互作用的序列。这些RNA在细胞核注射后保留在细胞核内，并在注射到细胞质中时输入。它们的核输入和保留不依赖于5 '端帽，需要在5'端附近的不完美的双链茎，并且依赖于与La蛋白的相互作用。进口的Sm-RNA，而使用的进口途径的蛋白质，是不同于U6 RNA。
Nuclear localization of an RNA is affected by cis-acting elements (NLEs) that lead to nuclear import or retention or to blockage of export from the nucleus. To identify such elements, we selected and analyzed transcripts that localized in the nuclei of Xenopus laevis oocytes. The RNAs were isolated from a collection of m(7)G-capped RNAs in which a combinatorial library (n = 20) of sequences had been inserted. One class of selected RNAs (Sm+) had a consensus Sm binding site (AAUUUUUGG) and bound Sm proteins in the cytoplasm; these RNAs resembled small nuclear RNAs like U1 and U5 RNAs in their bi-directional nucleocytoplasmic transport and their 5'-cap hypermethylation. Another class, Sm- RNAs, contained sequences that masked the m(7)G-caps of the RNAs and promoted interaction with La protein. These RNAs were retained within nuclei after nuclear injection and were imported when injected into the cytoplasm. Their nuclear import and retention were independent of a 5'-cap, required an imperfect double-stranded stem near the 5' end, and depended on interaction with La protein. Import of the Sm-- RNAs, while using the import pathway of proteins, was distinct from that of U6 RNA.