POSITIONAL CLONING OF THE FR LOCUS

FR 基因座的定位克隆

• 批准号: 2430496
• 负责人: SALLY A MACKENZIE
• 金额: $ 9.12万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2430496
• 关键词: Leguminoseae; cell nucleus; gene mutation; genetic library; genetic mapping; mitochondria; molecular cloning; plant genetics; pollen

DESCRIPTION: This proposal deals with the topic of nuclear-mitochondrial interactions. The question of how the nuclear genome maintains normal mitochondrial function in higher eukaryotes is addressed. In particular, the proposal focuses on the possible mechanisms that regulate segregation and transmission of mitochondria in a heteroplasmic population, and those that preclude the accumulation of mitochondrial mutations. The system under study is an interesting nuclear- mitochondrial interaction in common bean. The mitochondrial mutation is a cytoplasmic male sterility (CMS) mutation that results in the inability of the plant to produce viable pollen. The CMS trait in bean is associated with an insertion in the mitochondrial genome which generates a novel open reading frame designated pvs-orf239. The association of a mitochondrial rearrangement and production of novel proteins are a common theme in plant CMS systems. However, the bean CMS system has some unique features. The expression of the pvs protein during development of the pollen meiocytes leads to the accumulation of this aberrant protein not in mitochondria as expected but at the periphery of the cell in the developing callose layer. This presumably interferes with the cytokinesis events that lead to the production of normal pollen grains. Fertility is restored in strains containing the mitochondrial mutation by the action of one of several nuclear restorer genes. One of these genes, the Fr locus, is the focus of this proposal. Fr restores fertility to the CMS strain apparently by effecting the directed elimination of the mitochondrial mutation. To elucidate the molecular basis of Fr action, the proposal outlines a series of experiments aimed at the positional cloning of Fr. Physical mapping of the locus, the construction of a large-insert library for use in chromosome walking from tightly linked markers, and the isolation of cDNA clones derived from the putative Fr gene are outlined.

描述：本提案涉及核线粒体主题 互动。 核基因组如何保持正常的问题 解决了高等真核生物中的线粒体功能。 尤其， 该提案侧重于监管的可能机制 异质体中线粒体的分离和传输 人群，以及那些阻止线粒体积累的人群 突变。 正在研究的系统是一个有趣的核系统 普通豆中线粒体的相互作用。 线粒体突变 是一种细胞质雄性不育（CMS）突变，导致 植物无法产生有活力的花粉。 bean 中的 CMS 特征 与线粒体基因组中的插入有关 生成一个新颖的开放阅读框，命名为 pvs-orf239。 这 线粒体重排与新产物产生的关联 蛋白质是植物 CMS 系统中的一个常见主题。 然而，bean CMS 系统具有一些独特的功能。 pvs蛋白的表达 在花粉性母细胞的发育过程中，会导致 这种异常蛋白质并不像预期的那样存在于线粒体中，而是存在于 发育中的胼胝质层中的细胞外围。 这大概是 干扰导致产生的胞质分裂事件 正常的花粉粒。 含有以下物质的菌株的生育能力得到恢复 由几种核恢复剂之一的作用引起的线粒体突变 基因。 这些基因之一，Fr 基因座，是本研究的焦点 提议。 Fr 显然通过以下方式恢复了 CMS 菌株的生育能力 实现线粒体突变的定向消除。 到 为了阐明 Fr 作用的分子基础，该提案概述了 一系列旨在定位克隆 Fr 的实验。 身体的 基因座作图，构建大型插入文库以供使用 在染色体中从紧密连锁的标记中行走，并分离 概述了源自推定 Fr 基因的 cDNA 克隆。