Nuclear Gene Control of Chloroplast Gene Expression

叶绿体基因表达的核基因控制

• 批准号: 9512719
• 负责人: Laurens Mets
• 金额: $ 33.7万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-12-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9512719&HistoricalAwards=false
• 关键词: Nuclear; Gene; Control; Chloroplast; Expression

Mets 9512719 The long term objective of this project is to identify and characterize mechanisms that coordinate the expression of nuclear and organellar genes during the biogenesis of eukaryotic organelles. This project focuses on nuclear genes that determine the level of expression of a specific chloroplast gene: the rbcL gene that encodes the large subunit of the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). The study will exploit the unique genetic and molecular genetic properties of the unicellular green alga Chlamydomonas reinhardtii. We have developed a strong positive selection for RuBisCO-deficient mutants in C. reinhardtii and will generate a large collection of nuclear gene mutants that fail to produce RuBisCO, but produce normal amounts of other chloroplast gene products. These mutants will be characterized genetically (by dominance and allelism tests) and mechanistically through molecular studies of rbcL expression. Preliminary studies on one such mutant, 24DD, suggest that its rbcL mRNA is unstable does not support adequate large subunit synthesis. Experiments are proposed to confirm and extend these results, to identify and characterize the cis-acting target in the rbcL mRNA that distinguishes it from other chloroplast messages that are not destabilized in the mutant, and to initiate the cloning and characterization of the mutant gene and its wild type allele. %%% The RuBisCO enzyme, whose gene control is under study in this project, is known to be one of the most important elements that limits photosynthetic efficiency, water use efficiency and nitrogen use efficiency in plants. Eventual success in correcting of these limitations will depend not only upon understanding its biochemical and metabolic properties but also upon understanding how it's biosynthesis is controlled by the plant. This project will make a major contribution to that understanding. ***

该项目的长期目标是鉴定和表征在真核细胞器的生物发生过程中协调细胞核和细胞器基因表达的机制。 该项目的重点是核基因，决定了一个特定的叶绿体基因的表达水平：rbcL基因，编码大亚基的酶核酮糖-1，5-二磷酸羧化酶/加氧酶（RuBisCO）。 这项研究将利用独特的遗传和分子遗传特性的单细胞绿色衣藻莱茵衣藻。 我们已经开发了一个强大的正选择的RuBisCO缺陷型突变体在C。reinhardtii，并将产生大量的核基因突变体，这些突变体不能产生RuBisCO，但产生正常量的其他叶绿体基因产物。 这些突变体将通过rbcL表达的分子研究在遗传上（通过显性和等位性测试）和机理上进行表征。 对一个这样的突变体，24 DD，初步研究表明，它的rbcL mRNA是不稳定的，不支持足够的大亚基合成。 实验提出，以确认和扩展这些结果，以确定和表征的顺式作用的目标rbcL mRNA，区分它从其他叶绿体的消息，不稳定的突变体，并启动突变基因和其野生型等位基因的克隆和表征。 本项目正在研究基因控制的RuBisCO酶是限制植物光合效率、水分利用效率和氮素利用效率的最重要因素之一。 纠正这些限制的最终成功将不仅取决于了解其生物化学和代谢特性，而且还取决于了解其生物合成是如何由植物控制的。 该项目将对这一理解作出重大贡献。 ***