SOM 1, a small new gene required for mitochondrial inner membrane peptidase function inSaccharomyces cerevisiae
| Autor: | Elke Pratje, Georg Michaelis, Karlheinz Esser |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Transcription Genetic Protein subunit Genes Fungal Molecular Sequence Data Glycine Saccharomyces cerevisiae Biology medicine.disease_cause DNA Mitochondrial Electron Transport Complex IV Fungal Proteins Mitochondrial Proteins Plasmid Gene Frequency Gene Expression Regulation Fungal Endopeptidases Enzyme Stability Protein targeting Genetics medicine Amino Acid Sequence ORFS Genes Suppressor Molecular Biology Peptide sequence Gene Aspartic Acid Base Sequence L-Lactate Dehydrogenase Cell Membrane Serine Endopeptidases Chromosome Mapping Membrane Proteins RNA RNA Fungal Sequence Analysis DNA Repressor Proteins Subcloning Biochemistry Mutation L-Lactate Dehydrogenase (Cytochrome) Gene Deletion Peptide Hydrolases |
| Zdroj: | Molecular and General Genetics MGG. 252:437-445 |
| ISSN: | 1432-1874 0026-8925 |
| Popis: | IMP1 encodes a subunit of the mitochondrial inner membrane peptidase responsible for the proteolytic processing of cytochrome oxidase subunit 2 (Cox2) and cytochrome b2 (Cytb2). The molecular defect in an imp1 mutation and the characterisation of a high-copy-number suppressor is described. A deletion of the suppressor region causes respiration deficiency. The DNA sequence revealed three very small overlapping ORFs. Constructs which carried termination codons within the ORFs or lacked ATG initiation codons still retained complementing activity on a high-copy-number plasmid. Nevertheless, the possibility that the suppressor acts at DNA or RNA level could be excluded. Subcloning of the ORFs, complementation analysis in low-copy-number plasmids and transcript mapping identified the 222 bp ORF as the suppressor gene designated SOM1. The SOM1 gene is transcribed into a 375 bp polyadenylated RNA and the deduced amino acid sequence predicts a small protein of 8.4 kDa with no significant sequence similarity to known proteins. In the som1 deletion mutant, proteolytic processing of the Cox2 precursor is prevented and Cytb2 is strongly reduced. SOM1 represents a new small gene which encodes a novel factor that is essential for the correct function of the Imp1 peptidase and/or the protein sorting machinery. |
| Databáze: | OpenAIRE |
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