REGULATION OF MITOCHONDRIAL BIOGENESIS IN YEAST

酵母线粒体生物发生的调控

基本信息

批准号：
2415115
负责人：
RONALD A BUTOW
金额：
$ 34.2万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
1979
资助国家：
美国
起止时间：
1979-05-01 至 1998-04-30
项目状态：
已结题

项目摘要

The long-term goal of the proposed research is to understand the mechanisms of regulation of mitochondrial biogenesis in Saccharomyces cerevisiae. First, we will elucidate the functions of a putative ATP- dependent RNA helicase in mitochondria encoded by the nuclear suv3 gene. Suv3 is involved in various post-transcriptional activities in mitochondria, and is essential for maintenance of the wild-type mitochondrial genome. The properties of a mutant allele of sur3, call SUV3-1, suggests that suv3 functions in group I intron splicing, and in particular, to resolve excised group I introns from ribonucleoprotein (RNP) splicing complexes. This model will be tested, including the notion that SUV3-1 is a compromised RNA helicase. These studies will be extended to characterize group I intron RNP complexes, with initial emphasis on an 18S ribonucleoprotein particle containing the excised omega intron of the 21S rRNA gene. Using strains with an intronless wild-type mitochondrial genome, we will initiate studies to determine other functions of suv3 in mitochondrial RNA metabolism. Our second objective is to characterize a novel regulatory path we discovered called retrograde regulation, whereby the functional state of mitochondria can profoundly affect nuclear gene expression. We have proposed, and provided evidence supporting the idea, that retrograde regulation is a mechanisms for the cell to adjust to changes in mitochondrial function, biogenesis and inheritance. We wish to elucidate the mechanisms of signaling from mitochondria to the nucleus. Here, we will focus on two novel genes, RTG1 that encodes a new member of the basic helix-loop-helix (bHLH) family of transcription factors, and RTG2 that encodes a protein of unknown function. The products of both genes are required for retrograde regulation of the CIT2 gene, which encodes a peroxisomal isoform of citrate synthase that functions as part of the glyoxylate cycle. Retrograde regulation of CIT2 functions metabolically to provide citrate to mitochondria from the glyoxylate cycle under conditions where the TCA cycle may be limiting. Our aims are to 1) determine how the bHLH protein, RTG1, acts as a transcriptional switch for retrograde regulation; 2) determine the function of RTG2; 3) define through genetics and molecular approaches additional components of the retrograde pathway; and 4) elucidate the blocks in metabolic communication between the TCA and glyoxylate cycles in rtg1 and rtg2 mutants. These experiments should provide additional insights into the function of retrograde regulation.

拟议研究的长期目标是了解糖疗法中线粒体生物发生调节的机制酿酒酵母。首先，我们将阐明推定的ATP-的功能线粒体中的依赖性RNA解旋酶由核SUV3基因编码。 SUV3参与了各种转录后活动线粒体，对于维持野生型至关重要线粒体基因组。 SUR3突变等位基因的特性，致电 SUV3-1，表明SUV3在I组内含子剪接中起作用，并在特别是，从核糖核蛋白解决切除的I组内含子（RNP）剪接复合物。该模型将进行测试，包括 SUV3-1是损害的RNA解旋酶的观念。这些研究将是扩展到表征I组内含子RNP复合物，并具有初始强调含有切除的核糖核蛋白颗粒的18S 21S rRNA基因的欧米茄内含子。将菌株与无固有的菌株一起使用野生型线粒体基因组，我们将启动研究以确定 SUV3在线粒体RNA代谢中的其他功能。我们的第二个目的是表征我们发现的新型调节路径逆行调节，线粒体的功能状态可以深刻影响核基因表达。我们已经提出并提供了支持这个想法的证据，表明逆行调节是一种机制为了使细胞适应线粒体功能的变化，生物发生和继承。我们希望阐明来自线粒体到核。在这里，我们将专注于两个新型基因， RTG1编码基本螺旋 - 环螺旋（BHLH）的新成员转录因子家族和RTG2编码的RTG2 未知功能。这两个基因的产物都是逆行的 CIT2基因的调节，该基因编码过氧化物酶体同工型柠檬酸盐合酶作为甘酰基循环的一部分起作用。 CIT2的逆行调节作用以代谢提供柠檬酸盐在TCA的条件下从乙二基周期到线粒体周期可能是限制的。我们的目标是1）确定BHLH的方式蛋白质RTG1充当转录开关的逆行规定; 2）确定RTG2的功能； 3）通过遗传学定义分子方法逆行途径的其他组成部分； 4）阐明了TCA之间代谢通信的块 RTG1和RTG2突变体中的乙二醇周期。这些实验应该提供有关逆行调节功能的更多见解。