Regulation of mRNA Stability in Plastids

质体中 mRNA 稳定性的调节

• 批准号: 9604658
• 负责人: Wilhelm Gruissem
• 金额: $ 30万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9604658&HistoricalAwards=false
• 关键词: Regulation; mRNA; Stability; Plastids

9604658 Gruissem Current information suggests that regulated mRNA stability is an important control point of gene expression in light-dependent development of chloroplasts and activation of photosynthesis. Recent work on mRNA processing and turnover in prokaryotes, eukaryotes and cellular organelles indicate the 3'end plays a key role in generating functional mRNA and regulating its degradation. This laboratory previously has shown that mRNA 3' stem-loop structures act in concert with nucleases and regulatory proteins to direct correct mRNA processing or degradation in chloroplasts. These nucleases are assembled into a high molecular weight (HMW) complex, which is similar in function to the recently reported RNA 'degradosome' in E. coli, but in chloroplasts is regulated by ancillary nuclear-encoded CS-type RNA binding proteins to produced correctly processed and stable mRNA 3'-ends. Plants expressing antisense RNA to the CS-type proteins die early in development consistent with the critical role of these proteins in chloroplast function. Once a stable mRNA has been formed, its degradation is determined by RNA binding proteins that regulate the endonucleolytic removal of the stabilizing 3' stem-loop structure. Degradation of the cleaved RNA is accelerated by 3' polyadenylation, which also can accelerate degradation of the mature 3' stem-loop RNA by a light-regulated mechanism. These results indicate that in plant cells polyadenylation of cytoplasmic and plastid mRNAs operates in parallel but with different consequences for the metabolism of the respective mRNAs. This research will focus on the functional dissection of the chloroplast HMW nuclease complex using component proteins which have been purified and cloned. Combined biochemical and genetic approaches will clarify the roles of enzymes that participate in mRNA metabolism and establish the function of the CS-type RNA binding proteins in light-regulated chloroplast mRNA processing and decay. Understanding the mechanisms by which pla stid mRNA decay is regulated will provide important new information on the nuclear control of organelle gene expression, and because of the importance of photosynthesis for plant productivity, will have relevance to future plant and agricultural biotechnology. Current information suggests that regulated mRNA stability is an important control point of gene expression in light-dependent development of chloroplasts and activation of photosynthesis. This research will employ combined biochemical and genetic approaches to clarify the roles of enzymes that participate in mRNA metabolism and to establish the function of RNA binding proteins in light-regulated chloroplast mRNA processing and decay. Understanding the mechanisms by which chloroplast mRNA decay is regulated will provide important new information on the nuclear control of organelle gene expression, and because of the importance of photosynthesis for plant productivity, will have relevance to future plant and agricultural biotechnology.

9604658 Gruissem目前的信息表明，受调节的mRNA稳定性是叶绿体光依赖性发育和光合作用激活中基因表达的重要控制点。近年来对原核生物、真核生物和细胞器中mRNA加工和周转的研究表明，3 '端在产生功能性mRNA和调节其降解中起着关键作用。 该实验室先前已经表明，mRNA 3'茎环结构与核酸酶和调节蛋白协同作用，以指导叶绿体中正确的mRNA加工或降解。 这些核酸酶被组装成高分子量（HMW）复合物，其功能类似于最近报道的E.在叶绿体中由辅助的核编码的CS型RNA结合蛋白调节，以产生正确加工和稳定的mRNA 3 '端。表达CS-型蛋白的反义RNA的植物在发育早期死亡，这与这些蛋白在叶绿体功能中的关键作用一致。 一旦形成稳定的mRNA，其降解由RNA结合蛋白决定，所述RNA结合蛋白调节稳定的3'茎环结构的核酸内切去除。 切割的RNA的降解通过3'聚腺苷酸化加速，其也可以通过光调节机制加速成熟的3'茎环RNA的降解。 这些结果表明，在植物细胞中，细胞质和质体mRNA的聚腺苷酸化是平行的，但对各自mRNA的代谢具有不同的后果。 本研究将利用已纯化和克隆的叶绿体高分子量核酸酶复合体的组成蛋白，对叶绿体高分子量核酸酶复合体进行功能分析。 生物化学和遗传学相结合的方法将阐明参与mRNA代谢的酶的作用，并建立CS型RNA结合蛋白在光调控叶绿体mRNA加工和衰变中的功能。 了解plastid mRNA衰变的调节机制将为细胞器基因表达的核控制提供重要的新信息，并且由于光合作用对植物生产力的重要性，将与未来的植物和农业生物技术相关。 目前的信息表明，受调控的mRNA稳定性是叶绿体光依赖性发育和光合作用激活中基因表达的重要控制点。本研究将采用生物化学和遗传学相结合的方法来阐明参与mRNA代谢的酶的作用，并建立RNA结合蛋白在光调控叶绿体mRNA加工和衰变中的功能。 了解叶绿体mRNA衰变的调节机制，将提供重要的细胞器基因表达的核控制的新信息，由于光合作用对植物生产力的重要性，将有相关的未来植物和农业生物技术。