Aminoacyl-tRNA Synthesis by Pre-translational Amino Acid Modification

描述(由申请人提供)：小的非编码RNA的生物发生对于正常的细胞功能是必不可少的。必须成功地完成小RNA生物发生的许多步骤，以产生能够执行其特定细胞功能的成熟RNA。任何步骤的错误都可能导致异常RNA的积累，并对细胞产生有害后果。因此，能够测量RNA，确保生物发生的每一步的准确性，并消除异常RNA是正常细胞功能所必需的。这里提出的实验应该会让人们深入了解人们对有缺陷的、非编码的RNA被识别并以此为目标进行破坏的过程。Trf4p最近被证明在酵母中通过聚腺苷酸化和随后的外切体降解靶向突变的tRNA进行降解；我们将确定Trf4p在小的非编码RNA的质量控制中是否具有一般功能。此外，我们的数据表明La蛋白和Trf4p之间存在相互作用，La蛋白是第一个与新生RNA聚合酶III转录本结合的蛋白质；我们将研究La蛋白在小RNA质量控制中的作用。最后，我们还将研究另一个不同于Trf4p启动的途径的突变体tRNA的质量控制途径。

DESCRIPTION (provided by applicant): Biogenesis of small noncoding RNAs is essential for proper cell functioning. The many steps of small RNA biogenesis must each be successfully completed to produce a mature RNA that is able to perform its particular cellular function. Mistakes at any step can result in accumulation of aberrant RNAs and have deleterious consequences for the cell. Therefore, the ability to survey RNA, ensuring accuracy at each step of biogenesis, and eliminate aberrant RNA is necessary for normal cell functioning. The experiments proposed here should give insights into the poorly understood process by which defective, noncoding RNAs are recognized and targeted for destruction. Trf4p was recently shown to function in targeting a mutant tRNA for degradation via polyadenylation and subsequent degradation by the exosome in yeast; we will determine whether Trf4p has a general function in the quality control of small noncoding RNAs. Additionally, our data indicates an interaction between the La protein, the first protein to bind nascent RNA polymerase III transcripts, and Trf4p; we will examine the role of the La protein in small RNA quality control. Lastly, we will also examine the quality control pathway of another mutant tRNA that differs from the Trf4p-initiated pathway.