REGULATION OF MITOCHONDRIAL INHERITANCE IN YEAST

线粒体不能从头合成；相反，新形成的子体 细胞必须从母细胞继承它们的线粒体 组织。尽管线粒体的新陈代谢功能 研究广泛，但对分子机制知之甚少。 控制线粒体的传播。最近，一类重要的 基因(称为MDM，意为“线粒体分布和形态”) 通过使用对温度敏感的突变体进行鉴定 在酵母发芽期间破坏线粒体遗传。精准的 这些基因产物的功能还不清楚。除了两个之外，所有的 这些MDM基因由单个突变的等位基因表示，这表明 线粒体分割装置的其他组件仍然存在 以确定身份。 我们已经确定了线粒体所需的八个新基因 在东部萌发过程中转移到新形成的子细胞。我们建议 研究酵母线粒体分裂的分子基础 这8种新MDM的遗传、分子和生化特征 基因及其编码的蛋白质。首先，我们将结合使用 活体染色、间接免疫荧光和电子显微镜观察 描述线粒体遗传和形态缺陷的范围 由MDM基因突变引起。其次，野生型和突变型等位基因 这8个MDM基因将被克隆、测序和分析。这一分析 将使我们能够识别任何重要的结构主题和功能 预测蛋白质中的结构域。第三，我们将使用间接 免疫荧光和细胞分级实验确定 MDM蛋白的亚细胞定位。第四，我们将分析 Mdm突变体减数分裂过程中的线粒体分裂。这些研究 将使我们能够确定MDM蛋白是否介导线粒体 在减数分裂和有丝分裂期间的运动，可能揭示 在有丝分裂中不易观察到的线粒体分割 分割细胞。 我们提出的实验将为未来的分子， MDM蛋白功能的生化和遗传学分析。从长远来看- 术语，这些研究应该有助于我们对 细胞内线粒体运动的分子机制 在其他生物体的早期发育过程中。

Mitochondria cannot be synthesized de novo; instead, newly-formed daughter cells must inherit their mitochondria from the mother cell during division. Although the metabolic functions of mitochondria have been extensively studied, very little is known about the molecular mechanisms controlling mitochondrial transmission. Recently, an important class of genes (termed MDM for "mitochondrial distribution and morphology") has been identified through the use of temperature-sensitive mutants that disrupt mitochondrial inheritance during yeast budding. The precise functions of these gene products are not yet understood. All but two of these MDM genes are represented by single mutant alleles suggesting that additional components of the mitochondrial partitioning apparatus remain to be identified. We have identified eight new genes that are required for mitochondrial transfer into newly formed daughter cells during east budding. We propose to study the molecular basis of mitochondrial partitioning in yeast via the genetic, molecular and biochemical characterization of these 8 new MDM genes and the proteins they encode. FIRST, we will use a combination of vital staining, indirect immunofluorescence, and electron microscopy to characterize the range of mitochondrial inheritance and morphology defects caused by mutations in MDM genes. SECOND, wild-type and mutant alleles of the 8 MDM genes will be cloned, sequenced and analyzed. This analysis will allow us to identify any important structural motifs and functional domains in the predicted proteins. THIRD, we will use indirect immunofluorescence and cell fractionation experiments to determine the subcellular location of Mdm protein. FOURTH, we will analyze mitochondrial partitioning during meiosis in mdm mutants. These studies will allow us to determine whether Mdm proteins mediate mitochondrial movements during both meiosis and mitosis and may reveal details of mitochondrial partitioning that cannot be easily visualized in mitotically dividing cells. The experiments we propose will lay the foundation for future molecular, biochemical and genetic analyses of Mdm protein function. In the long- term, these studies should contribute to our basic understanding of the molecular mechanisms underlying mitochondrial movements during cell division and during early development in other organisms.