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キーワード:
ATP-Dependent Proteases
Adenosine Triphosphate/*physiology
Cytochrome b Group/*biosynthesis/genetics
DNA, Mitochondrial/*genetics
Electron Transport Complex IV/*biosynthesis/genetics
Endoribonucleases/metabolism
Fungal Proteins/genetics/*physiology
*Gene Expression Regulation, Fungal
Genes, Suppressor
Introns/*genetics
Mitochondria/metabolism
Mitochondrial Proteins
Nucleotidyltransferases/metabolism
RNA Precursors/metabolism
RNA Splicing/*physiology
RNA, Fungal/metabolism
RNA, Messenger/metabolism
Saccharomyces cerevisiae/*genetics/metabolism
*Saccharomyces cerevisiae Proteins
Serine Endopeptidases/genetics/*physiology
Transcription, Genetic
要旨:
The ATP-dependent PIM1 protease, a Lon-like protease localized in the mitochondrial matrix, is required for mitochondrial genome integrity in yeast. Cells lacking PIM1 accumulate lesions in the mitochondrial DNA (mtDNA) and therefore lose respiratory competence. The identification of a multicopy suppressor, which stabilizes mtDNA in the absence of PIM1, enabled us to characterize novel functions of PIM1 protease during mitochondrial biogenesis. The synthesis of mitochondrially encoded cytochrome c oxidase subunit I (CoxI) and cytochrome b (Cob) is impaired in pim1 mutants containing mtDNA. PIM1-mediated proteolysis is required for the translation of mature COXI mRNA. Moreover, deficiencies in the splicing of COXI and COB transcripts, which appear to be restricted to introns encoding mRNA maturases, were observed in cells lacking the PIM1 gene. Transcripts of COXI and COB genes harboring multiple introns are degraded in the absence of PIM1. These results establish multiple, essential functions of the ATP-dependent PIM1 protease during mitochondrial gene expression.
