Identification of a novel cis-acting RNA element involved in nuclear export of hY RNAs.
Identification of a novel cis-acting RNA element involved in nuclear export of hY RNAs.
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DOI：
10.1017/s1355838201002503
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发表时间：
2001-05
期刊：
影响因子：
4.5
通讯作者：
S. Rutjes;E. Lund;A. van der Heijden;C. Grimm;W. V. van Venrooij;G. Pruijn
中科院分区：
文献类型：
--
作者：
S. Rutjes;E. Lund;A. van der Heijden;C. Grimm;W. V. van Venrooij;G. Pruijn
Ro RNPs是一种功能未知的小的细胞质RNA-蛋白质复合体，目前已在所有研究的后生动物细胞中发现。在人类细胞中，Ro RNPs由四个被称为Hy RNAs的小RNA分子之一和至少两个特征良好的蛋白质Ro60和La组成。在以前的非洲爪哇卵母细胞显微注射研究中，我们表明完整的Ro60结合位点(Stem-loop 1)是有效的hY1 RNA核输出的先决条件，而完整的La结合位点促进核保留(Simons等人)。RNA，1996，2：264-273)。在这里，我们提供的证据表明，在所有Hy RNA中发现的保守的碱基配对茎结构的远端一半(茎2)也在出口过程中发挥关键作用。含有该区域的最小RNA分子L1S2 RNA有效地竞争全长hY1 RNA的输出，并以Ro60不依赖和RanGTP依赖的方式非常快速地输出。对该RNA的突变分析表明，一个没有特定核苷酸序列的5‘/3’末端双链茎结构(>；10bp)构成了一个新的核输出元件(NEE)。交叉竞争研究表明，这种类型的nee也可能涉及其他类别的RNA的出口。与全长hY1 RNA一样，L1S2 RNA也竞争ET-202 RNA的出口，ET-202 RNA是一种在核运输抑制剂VSV Matrix Protein存在下有效的核出口RNA(Grimm等人。《美国学报》，1997年，94：10122-10127)。然而，VSV-M蛋白强烈抑制L1S2 RNA的输出，表明这些RNA使用部分重叠的输出途径，但不是相同的输出途径。我们认为Y RNA的输出是由不同Y RNA之间保守的5‘/3’双链茎区的两个相邻的顺式作用元件介导的。
Ro RNPs are small cytoplasmic RNA-protein complexes of unknown function that have been found in all metazoan cells studied so far. In human cells, Ro RNPs consist of one of four small RNA molecules, termed hY RNAs and at least two well-characterized proteins, Ro60 and La. In previous Xenopus laevis oocyte microinjection studies, we showed that an intact Ro60 binding site (Stem-loop 1) is a prerequisite for efficient nuclear export of hY1 RNA, whereas an intact La-binding site promotes nuclear retention (Simons et al. RNA, 1996, 2:264-273). Here we present evidence that the distal half (Stem 2) of the conserved base-paired stem structure found in all hY RNAs also plays a critical role in the export process. A minimal RNA molecule containing this region, L1S2 RNA, competes effectively for the export of full-length hY1 RNAs and is itself exported very rapidly in a Ro60-independent and RanGTP-dependent manner. Mutational analyses of this RNA shows that a 5'/3' terminal double-stranded stem structure (>10 bp) of no specific nucleotide sequence constitutes a novel nuclear export element (NEE). Cross-competition studies indicate that this type of NEE may also be involved in export of other classes of RNAs. Like full-length hY1 RNA, L1S2 RNA also competes for export of ET-202 RNA, an RNA that was selected for its efficient nuclear export in the presence of the nuclear transport inhibitor, VSV Matrix protein (Grimm et al. Proc Natl Acad Sci USA, 1997, 94:10122-10127). However, export of L1S2 RNA is strongly inhibited by VSV-M protein, showing that these RNAs use partially overlapping, but not identical export pathways. We propose that export of Y RNAs is mediated by two contiguous cis-acting elements in the 5'/3' double-stranded stem region that is conserved between different Y RNAs.