BIOGENESIS OF MITOCHONDRIA IN NEUROSPORA

这项拟议的研究是对线粒体的生化和遗传学研究。 黑孢子菌的生物发生。这项研究的长期目标是确定 核和线粒体遗传系统的作用以及 了解这些角色是如何协调和调整的。具体目标 落在两个方面：(A)线粒体iBosome组装，这一过程 需要核和线粒体遗传系统之间的相互作用， 和(B)线粒体质粒，即存在于 某些脉孢菌菌株。在以前的工作中。我们确定了并 核内和核外影响神经孢子菌突变体的特征 线粒体核糖体组装。在拟议的研究中，我们将使用 分离特定核基因的核突变体 线粒体核糖体组装。最初的目标是隔离核 编码线粒体核糖体蛋白的基因，以表征这些 基因，并研究它们的调控。在这一部分中的辅助目标 研究目的是进一步开发分离和分离技术 脉孢菌核基因的分析。在之前的工作中，我们展示了一个 线粒体核糖体蛋白S-5(Mr=52,000)是在体外合成的。 线粒体和获得的证据表明，这种蛋白质是 线粒体小核糖体亚基的组装。最新DNA序列 分析表明，S-5编码于线粒体大分子rRNA中 内含子。作为唯一由线粒体合成的线粒体核糖体 作为一种蛋白质，S-5在调控中发挥了关键作用。我们建议 继续研究S-5在线粒体核糖体组装中的作用。 最后，我们鉴定并鉴定了脉孢子虫线粒体。 与标准线粒体DNA不是同源的质粒。DNA序列 脉孢子菌毛里西维尔-1c株3.6kb的质粒 Crassa表明它包含一个开放阅读框架，可以编码一个 蛋白质长达710个氨基酸。此外，还有几个特点 表明它可能属于一类可移动的遗传 曾经是或现在是主要的祖先的类型的元素 线粒体DNA内含子群(组I)。我们建议继续研究 脉孢菌丝核质粒的鉴定和鉴定 质粒编码蛋白(S)，并直接检测其能力 作为可移动元件的质粒。

The proposed research is a biochemical and genetic study of mitochondrial biogenesis in Neruosporo. The long term goals of this study are to define the roles of the nuclear and mitochondrial genetic systems and to understand how these roles are coordinated and modulated. Specific aims fall in two areas (a) mitochondrial iibosome assembly, a process that requires interaction between the nuclear and mitochondrial genetic systems, and (b) mitochondrial plasmids, candidate mobile elements that are found in certain Neurospora strains. In previous work. we identified and characterized nuclear and extranuclear Neurosporo mutants that affect mitochondrial ribosome assembly. In the proposed research, we would use the nuclear mutants to isolate specific nuclear genes that function in mitochondrial ribosome assembly. Initial objectives are to isolate nuclear genes that encode mitochondrial ribosomal proteins, to characterize these genes, and to study their regultion. An ancillary goal in this part of the research is to develop further the technology for the isolation and analysis of Neurospora nuclear genes. In previous work, we showed that one mitochondrial ribosomal protein, S-5 (Mr = 52,000), is synthesized in the mitochondria and obtained evidence that this protein is required for the assembly of mitochondrial small ribosomal subunits. Recent DNA sequence analysis suggests that S-5 is encoded within the mitochondrial large rRNA intron. As the only mitochondrially-synthesized mitochondrial ribosomal protein, S-5 is in a position to play a key role in regulation. We propose to continue to study the role of S-5 in mitochondrial ribosome assembly. Finally, we have identified and characterized Neurospora mitochondrial plasmids that are not homologous to the standard mtDNA. The DNA sequence of the 3.6 kb plasmid present in the Mauriceville-lc strain of Neurospora crassa shows that it contains an open reading frame that could encode a protein as long as 710 amino acids. In addition, several characteristics of the plasmid suggest that it may belong to a class of mobile genetic elelments of the type that were or are the progenitors of the predominant group of mtDNA introns (Group I). We propose to continue to study Neurospora mitochondrial plasmids, to identify and charactrize the plasmid-encoded protein(s), and to test directly the ability of the plasmids to function as mobile elements.