HUMAN MITOCHONDRIAL 3' END PROCESSING AND DISEASE

描述（由申请人提供）：真核tRNA转录为 前体5号？最后的领导者和3？末端尾部是内切核酸 被RNase P和3？- tRNase。三个？结束CCA不是 转录编码，并且必须通过tRNA核苷酸转移酶添加， 3号？最终由3？tRNase。三个？结束CCA，一个反决定因素 真核生物3？- tRNase（Mohan等人，RNA 5：245，1999），阻止成熟的tRNA从 通过3个循环？作为底物或作为抑制剂的tRNase，以及取代 在中间受体茎干扰3？- tRNase加工（Mohan和Levinger， JMB 303：605，2000）。人线粒体tRNASer（UCN）中的A7445 G突变， 其引起非综合征性耳聋（Guan等人，MCB 18：5868，1998），变化 G I UCU-到G I CCU-紧接着3？tRNase切割位点（I）， 可能会产生3？tRNase抗决定簇。使用人类细胞培养 线粒体提取物和体外产生的tRNA前体，候选人 建议的特点假设3？端部加工缺陷和 伴随这一替换和其他五个替换的tRNA结构变化 在与人类线粒体疾病相关的tRNASer（UCN）中，其中两种还 引起非综合征性耳聋。此外，他还将研究 线粒体tRNAIle和tRNALeu（UUR）在tRNA结构上的取代， 三个？tRNase加工。

DESCRIPTION (provided by applicant): Eukaryotic tRNAs are transcribed as precursors. The 5? end leader and 3? end trailer are endonucleolytically removed by RNase P and by 3?-tRNase, respectively. 3? end CCA is not transcriptionally encoded, and must be added by tRNA nucleotidyltransferase to the 3? end produced by 3?- tRNase. 3? end CCA, an anti-determinant for eukaryotic 3?-tRNase (Mohan et al., RNA 5: 245,1999), prevents mature tRNA from cycling through 3?-tRNase as a substrate or as an inhibitor, and substitutions in mid-acceptor stem interfere with 3?-tRNase processing (Mohan and Levinger, JMB 303: 605, 2000). The A7445G mutation in human mitochondrial tRNASer(UCN), which causes non-syndromic deafness (Guan et al., MCB 18: 5868, 1998), changes G I UCU--- to G I CCU--- immediately following the 3?-tRNase cleavage site (I), and may produce a 3?-tRNase anti-determinant. Using a human cell culture mitochondrial extract and tRNA precursors produced in vitro, the candidate proposes to characterize the postulated 3? end processing defect and the change(s) in tRNA structure which accompany this and five other substitutions in tRNASer(UCN) linked with human mitochondrial disease, two of which also cause nonsyndromic deafness. In addition, he will study the effects of substitutions in mitochondrial tRNAIle and tRNALeu(UUR) on tRNA structure and 3?-tRNase processing.