GENETIC AND BIOCHEMICAL ANALYSIS OF PHYCOBILISOMES

藻胆体的遗传和生化分析

• 批准号: 3283160
• 负责人: ARTHUR R GROSSMAN
• 金额: $ 12.3万
• 依托单位: CARNEGIE INSTITUTION OF WASHINGTON, D.C.
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-12-01 至 1992-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3283160
• 关键词: Cyanophyta; evolution; gene expression; genetic manipulation; genetic recombination; genetic transcription; genome; mutant; nucleic acid hybridization; nucleic acid probes; nucleic acid sequence; photosynthesis; phycobilin; plant genetics; plant proteins; protein biosynthesis; regulatory gene

The aim of this proposal is to understand the regulatory mechanisms involved in controlling the expression of genes encoding the components of the phycobilisome, the major light- harvesting complex in cyanobacteria and red algae. Ultimately this research will extend our understanding of how light is perceived and converted into biochemical signals which alter expression of specific genes. The technology developed and exploited during the course of this work may expand our knowledge of the ways in which cyanobacteria can be genetically manipulated and benefit the analyses of such processes as nitrogen fixation, photosynthesis, acclimation to stress and utilization and degradation of organic compounds. Levels of specific light harvesting, pigmented phycobiliproteins are exquisitely responsive to light quality in some cyanobacteria. This modulation, probably the consequence of changes in the activity of specific phycobiliprotein genes, results in more efficient absorption of prevalent wavelengths of light by the phycobilisome. With information now available on the organization, nucleotide sequences and transcriptional characteristics of phycobiliprotein and linker polypeptide (nonpigmented components of the phycobilisome) genes, we can develop both in vivo and in vitro systems for analyzing the function of the individual phycobilisome polypeptides, and the ways in which the genes for these polypeptides are regulated. Gene transfer techniques (conjugation, transformation) will be used to target lesions into specific phycobiliprotein or linker genes (or genes clustered with the phycobiliprotein and linker genes). Characterization of these mutants will help define the role of these genes in the biosynthesis of the phycobilisome. Gene transfer technology will also enable us to determine which sequence elements (cis acting factors), probably located 5' to the site of transcription initiation, are important to regulated phycobiliprotein gene expression. furthermore, by fusing these regulatory sequences to genes encoding proteins which are toxic to the cyanobacterium, we may be able to select regulatory mutants (organisms which cannot respond to changing light quality). To complement in vivo examination of gene regulation, we will develop an in vitro transcription system (that reflects in vivo regulation) and use it to define the individual components required for regulated expression of the biliprotein genes. These may include both unique species of RNA polymerase and trans acting factors which bind regulatory sequences. Combining in vitro and in vivo technology should enable us to define the molecular processes involved in phycobilisome biosynthesis.

这项建议的目的是了解监管机构 调控基因表达的机制 编码藻胆体的组成部分，主要的光- 蓝藻和红藻的收获复合体。最终 这项研究将扩大我们对光的理解 感知并转换成生化信号，从而改变 特定基因的表达。开发和开发的技术 在此工作过程中被利用可能会扩展我们的 关于蓝藻遗传方式的知识 被操纵，并有利于对以下过程的分析 固氮，光合作用，适应压力和 有机化合物的利用和降解。 特定捕光能力、色素藻胆蛋白的水平 在一些蓝藻中对光质反应灵敏。 这种调制，可能是由于 特定藻胆蛋白基因的活性，导致更多 对普遍波长的光的有效吸收 藻胆体。现在，您可以在 组织、核苷酸序列和转录 藻胆蛋白和连接物多肽的特性 (藻胆体的非色素成分)基因，我们可以 开发体内和体外分析系统 单个藻胆体多肽的功能，以及 这些多肽基因的调控方式。 基因转移技术(接合、转化)将是 用于靶向特定藻胆蛋白或连接物的损伤 基因(或与藻胆蛋白和连接物聚集在一起的基因 基因)。对这些突变体的表征将有助于确定 这些基因在藻胆体生物合成中的作用。基因 转让技术还将使我们能够确定 序列元件(顺式作用因子)，可能位于5‘端 转录起始位置，对调控很重要 藻胆蛋白基因的表达。此外，通过融合这些 编码有毒蛋白质的基因的调控序列 对于蓝藻，我们或许可以选择调控 突变体(不能对变化的光做出反应的生物体 质量)。 为了补充体内基因调控的检测，我们将 开发一种体外转录系统(在体内反映 法规)，并使用它来定义所需的各个组件 用于调节胆蛋白基因的表达。这些可能 包括RNA聚合酶和反式作用独特物种 结合调控序列的因子。在体外和体外结合 活体技术应该使我们能够定义分子 参与藻胆体生物合成的过程。