Caenorhabditis elegans embryos contain only one major species of Ro RNP.
Caenorhabditis elegans embryos contain only one major species of Ro RNP.
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发表时间：
1995-05
期刊：
影响因子：
4.5
通讯作者：
D. J. V. Horn;Dan Eisenberg;Charles A. O'Brien;S. Wolin
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作者：
D. J. V. Horn;Dan Eisenberg;Charles A. O'Brien;S. Wolin
在几乎所有的脊椎动物细胞中，Ro RNP由60-kDa Ro自身抗原组成，该抗原与几种称为Y RNA的小细胞质RNA分子之一结合。因为在非洲爪蟾卵母细胞中也发现60-kDa Ro自身抗原与5S rRNA的缺陷前体复合，我们提出该蛋白质在5S RNA生物合成的质量控制或丢弃途径中起作用（奥布莱恩CA，Wolin SL，1994，基因与发育8：2891 - 2903）。Y RNA在该途径中的作用尚不清楚。为了开始Ro RNP功能的遗传分析，我们已经表征了线虫小杆线虫中的这些颗粒。梭线虫Ro蛋白比脊椎动物蛋白大12 kDa;较大的尺寸部分是由于N-末端延伸和RNA识别基序中的两个插入。与所有先前描述的脊椎动物物种相比，Ro蛋白似乎与C中的单个Y RNA结合。优美的与脊椎动物Y RNA相似，C.线虫Y RNA可以折叠形成富含嘧啶的内环和5 '和3'端碱基配对的长茎。茎内是一个保守的凸出螺旋，被认为是Ro蛋白的结合位点。有趣的是，虽然人类蛋白质可以结合线虫Y RNA，但C。elegans蛋白不结合人Y RNA。这是无脊椎动物物种中Ro RNP的首次描述。
In virtually all vertebrate cells, Ro RNPs consist of the 60-kDa Ro autoantigen bound to one of several small cytoplasmic RNA molecules known as Y RNAs. Because the 60-kDa Ro autoantigen is also found complexed with defective precursors of 5S rRNA in Xenopus oocytes, we have proposed that this protein functions in a quality control, or discard pathway, for 5S RNA biosynthesis (O'Brien CA, Wolin SL, 1994, Genes & Dev 8:2891-2903). The role of the Y RNAs in this pathway is unknown. To begin a genetic analysis of Ro RNP function, we have characterized these particles in the nematode Caenorhabditis elegans. The C. elegans Ro protein is 12 kDa larger than the vertebrate protein; the larger size is due in part to an N-terminal extension and to two insertions in the RNA recognition motif. In contrast to all previously described vertebrate species, the Ro protein appears bound to a single Y RNA in C. elegans. Similar to vertebrate Y RNAs, the C. elegans Y RNA can be folded to form a pyrimidine-rich internal loop and a long stem in which the 5' and 3' ends are base paired. Within the stem is a conserved bulged helix that is proposed to be the binding site of the Ro protein. Interestingly, although the human protein can bind the nematode Y RNA, the C. elegans protein does not bind human Y RNAs. This is the first description of Ro RNPs in an invertebrate species.