NUCLEAR ENCODED GENES REGULATE CHLOROPLAST TRANSLATION

核编码基因调节叶绿体翻译

• 批准号: 2741870
• 负责人: AMYBETH COHEN
• 金额: $ 9.57万
• 依托单位: CALIFORNIA STATE UNIVERSITY FULLERTON
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2741870
• 关键词: Chlamydomonas; RNA binding protein; biological signal transduction; chloroplasts; genetic library; genetic regulation; genetic transcription; genetic translation; messenger RNA; molecular cloning; photosynthesis; plant genetics

A set of nuclear-encoded proteins that bind with high specificity and affinity to the 5'-untranslated region (UTR) of the chloroplast- encoded psbA mRNA have been identified in the unicellular green alga Chlamydomonas reinhardtii. Binding of these proteins to 5'-UTR is required for translation of the psbA mRNA and is regulated through elevated ADP levels and redox potential; two physiological events that are linked to photosynthesis. The cDNAs representing three of these translational activators have been isolated. Sequence analysis of two of the cDNAs has revealed that the corresponding proteins represent a poly A binding protein and a protein disulfide isomerase. A third protein at this time has no assigned function. We have produced antisera against these proteins, and have isolated two of the genomic clones: a screen of a genomic library should allow isolation of the third clone. We plan to characterize the primary signal and other components in the signal transduction pathway that regulate each of the nuclear-encoded psbA binding protein genes in order to understand how their expression influences translation of the psbA mRNA. These studies represent the first to address the characterization of cloned translational activators in plants, and will provide insight into the primary signals that regulate the expression of nuclear-encoded translational activators. Nuclear-encoded proteins that regulate the translation of mitochondrial mRNAs have also been identified in yeast, however, the corresponding genes have not been isolated. Therefore, this research should provide important insight into the molecular mechanism(s) that signal the expression of nuclear-encoded translational activators, information which will be applicable to those systems utilizing nuclear/organelle cross-communication.

已在单细胞绿藻莱茵衣藻中鉴定出一组核编码蛋白，它们以高特异性和亲和力与叶绿体编码的 psbA mRNA 的 5'-非翻译区 (UTR) 结合。这些蛋白质与 5'-UTR 的结合是 psbA mRNA 翻译所必需的，并通过升高的 ADP 水平和氧化还原电位进行调节；与光合作用有关的两个生理事件。代表其中三种翻译激活剂的 cDNA 已被分离出来。对其中两个 cDNA 的序列分析表明，相应的蛋白质代表聚 A 结合蛋白和蛋白质二硫键异构酶。 此时第三种蛋白质还没有指定的功能。 我们已经生产了针对这些蛋白质的抗血清，并分离了两个基因组克隆：基因组文库的筛选应该允许分离第三个克隆。我们计划表征信号转导途径中调节每个核编码的 psbA 结合蛋白基因的主要信号和其他成分，以了解它们的表达如何影响 psbA mRNA 的翻译。这些研究首次解决了植物中克隆翻译激活因子的表征问题，并将深入了解调节核编码翻译激活因子表达的主要信号。在酵母中也发现了调节线粒体 mRNA 翻译的核编码蛋白，但相应的基因尚未分离。因此，这项研究应该为核编码翻译激活剂表达信号的分子机制提供重要的见解，这些信息将适用于利用核/细胞器交叉通讯的系统。