4] In Organello mitochondrial protein and RNA synthesis systems from Saccharomyces cereuisiae

Abstract

Publisher Summary This chapter describes yeast in organello systems that have been optimized for mitichondrial protein and RNA synthesis. The mitochondrial genome of Saccharomyces cerevisiae encodes eight polypeptide subunits of respiratory proteins (cytochrome-c oxidase subunits I, II, and III, cytochrome b, and ATP synthase subunits 6, 8, and 9), var1 (a ribosomal protein), several proteins involved in RNA splicing, large and small rRNAs, 24 tRNAs, and an RNA component of an RNase P enzyme involved in tRNA processing. In contrast, isolated yeast mitochondrial (in organello) translation and transcription systems have been developed for studying the various aspects of mitochondrial gene expression in vitro . These systems are used to determine the stoichiometry of transcription and translation of the major mitochondrial gene products to determine that mitochondrial transcription and translation are not obligately coupled, to establish that mitochondrial translation products are inserted into the inner mitochondrial membrane cotranslationally, and to study proteolytic turnover of mitochondrial translation products.