NAM9 nuclear suppressor of mitochondrial ochre mutations in Saccharomyces cerevisiae codes for a protein homologous to S4 ribosomal proteins from chloroplasts, bacteria, and eucaryotes
| Autor: | Barbara Szczesniak, K Wrobel, Magdalena Boguta, P Borsuk, Anna Kruszewska, A Dmochowska, J Lazowska, P P Slonimski, A Gargouri |
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| Rok vydání: | 1992 |
| Předmět: |
Ribosomal Proteins
Mitochondrial DNA Chloroplasts Saccharomyces cerevisiae Proteins Transcription Genetic Mutant Molecular Sequence Data Saccharomyces cerevisiae Biology MT-RNR1 Gene product Fungal Proteins Transformation Genetic Ribosomal protein Amino Acid Sequence Cloning Molecular DNA Fungal Genes Suppressor Gene Molecular Biology HSPA9 Genetics Bacteria Base Sequence Eukaryota Nuclear Proteins Cell Biology Ribosomal RNA Plants Mitochondria Repressor Proteins Mutation Sequence Alignment Research Article |
| Zdroj: | Molecular and Cellular Biology. 12:402-412 |
| ISSN: | 1098-5549 0270-7306 |
| DOI: | 10.1128/mcb.12.1.402 |
| Popis: | We report the genetic characterization, molecular cloning, and sequencing of a novel nuclear suppressor, the NAM9 gene from Saccharomyces cerevisiae, which acts on mutations of mitochondrial DNA. The strain NAM9-1 was isolated as a respiration-competent revertant of a mitochondrial mit mutant which carries the V25 ochre mutation in the oxi1 gene. Genetic characterization of the NAM9-1 mutation has shown that it is a nuclear dominant omnipotent suppressor alleviating several mutations in all four mitochondrial genes tested and has suggested its informational, and probably ribosomal, character. The NAM9 gene was cloned by transformation of the recipient oxi1-V25 mutant to respiration competence by using a gene bank from the NAM9-1 rho o strain. Orthogonal-field alternation gel electrophoresis analysis and genetic mapping localized the NAM9 gene on the right arm of chromosome XIV. Sequence analysis of the NAM9 gene showed that it encodes a basic protein of 485 amino acids with a presequence that could target the protein to the mitochondrial matrix. The N-terminal sequence of 200 amino acids of the deduced NAM9 product strongly resembles the S4 ribosomal proteins from chloroplasts and bacteria. Significant although less extensive similarity was found with ribosomal cytoplasmic proteins from lower eucaryotes, including S. cerevisiae. Chromosomal inactivation of the NAM9+ gene is not lethal to the cell but leads to respiration deficiency and loss of mitochondrial DNA integrity. We conclude that the NAM9 gene product is a mitochondrial ribosomal counterpart of S4 ribosomal proteins found in other systems and that the suppressor acts through decreasing the fidelity of translation. |
| Databáze: | OpenAIRE |
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