The La protein in Schizosaccharomyces pombe: a conserved yet dispensable phosphoprotein that functions in tRNA maturation.
The La protein in Schizosaccharomyces pombe: a conserved yet dispensable phosphoprotein that functions in tRNA maturation.
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DOI：
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发表时间：
1997-12
期刊：
影响因子：
4.5
通讯作者：
D. J. V. Horn;C. Yoo;D. Xue;Huafang Shi;S. Wolin
中科院分区：
文献类型：
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作者：
D. J. V. Horn;C. Yoo;D. Xue;Huafang Shi;S. Wolin
大多数RNA聚合酶III转录本在合成后立即被称为La自身抗原的丰富的核磷蛋白结合。在芽殖酵母Saccharomyces cerevisiae中进行的实验已经揭示，La蛋白与tRNA前体的结合是许多tRNA的3'末端的核酸内切成熟所必需的。在不存在该蛋白质的情况下，这些tRNA的3'末端被核酸外切酶修剪（Yoo CJ，Wolin SL，1997，Cell 89：393-402）。在这里，我们报告的La蛋白在裂殖酵母粟酒裂殖酵母的表征。正如对芽殖酵母所描述的那样，S.缺乏La蛋白的粟酒裂殖酵母细胞是有活力的，并且在前-tRNA成熟的途径中表现出改变。引入人S.酿酒酵母或S.将粟酒裂殖酵母La蛋白导入这些细胞中使检测到的tRNA加工中间体的模式恢复到野生型细胞的模式。通过从用32 P-正磷酸盐代谢标记的细胞中进行免疫沉淀，我们证明了S。pombe和S.与人La蛋白一样，酿酒酵母La蛋白在体内被磷酸化。因此，虽然La蛋白在这些酵母中生长缓慢，但该蛋白的结构及其在前tRNA成熟中的功能在整个进化过程中高度保守。
Most RNA polymerase III transcripts are bound immediately after synthesis by an abundant nuclear phosphoprotein known as the La autoantigen. Experiments performed in the budding yeast Saccharomyces cerevisiae have revealed that binding of the La protein to tRNA precursors is required for the endonucleolytic maturation of the 3' terminus of many tRNAs. In the absence of this protein, the 3' ends of these tRNAs are trimmed by exonucleases (Yoo CJ, Wolin SL, 1997, Cell 89:393-402). Here we report the characterization of the La protein in the fission yeast Schizosaccharomyces pombe. As was described for budding yeast, S. pombe cells lacking the La protein are viable and exhibit alterations in the pathway of pre-tRNA maturation. Introduction of either the human, S. cerevisiae, or S. pombe La protein into these cells restores the detected pattern of tRNA processing intermediates to that of wild-type cells. By performing immunoprecipitations from cells that were metabolically labeled with 32P-orthophosphate, we demonstrate that the S. pombe and S. cerevisiae La proteins, like the human La protein, are phosphorylated in vivo. Thus, although the La protein is dispensable for growth in these yeasts, both the structure of the protein and its function in pre-tRNA maturation have been highly conserved throughout evolution.