Messenger RNA Processing in Chloroplasts

这项建议的目的是研究叶绿体的mRNA加工，重点是mRNA的剪接，以此来加深我们对叶绿体的生物发生和功能的理解。之前的结果提出了一些有趣的问题，涉及菠菜叶绿体中编码9个叶绿体ATP合成酶亚基中4个的基因簇的加工和剪接。初步数据表明，叶绿体mRNA的剪接可能导致同一内含子内的多个分支点。这项提案的三个目标之一是调查这些初步结果。PI已在菠菜叶绿体提取物中检测到剪接活性。这项建议的两个目标是致力于这种体外剪接活性的稳定性和初步表征研究。目前尚不清楚剪接是否是基因表达控制中的限速步骤，但它是生产几种重要基因产物不可缺少的步骤。在这项计划中，计划在体内和体外研究叶绿体剪接，以开始了解这一复杂的过程和调节它的因素。叶绿体基因的表达受多种因素的调控，包括光、热胁迫和生理因素。这项工作将有助于阐明调控叶绿体生物发生和功能的控制点。

The purpose of this proposal is to study chloroplast mRNA processing, with an emphasis on mRNA splicing, as a way to enhance our understanding of chloroplast biogenesis and function. Previous results have posed intriguing questions about the processing and splicing of a gene cluster in spinach chloroplasts that encodes four of the nine chloroplast ATP synthase subunits. Preliminary data suggests that chloroplast mRNA splicing may result in multiple branch points within the same intron. One of the three objectives of this proposal is to investigate those preliminary results. The PI has detected splicing activity in spinach chloroplast extracts. Tow objectives of this proposal are dedicated to the stabilization and initial characterization studies on this in vitro splicing activity. It is not known whether splicing is a rate limiting step in the control of gene expression, but it is an indispensable step in the production of several essential gene products. In this proposal, the plan is to study chloroplast splicing both in vivo and in vitro in order to begin to understand this complex process and the factors that regulate it. Chloroplast gene expression is regulated by several factors including light, heat stress, and physiological factors. This work will help to elucidate control points that regulate chloroplast biogenesis and function.//