CLONING AND CHARACTERIZATION OF MRP10, A YEAST GENE CODING FOR A MITOCHONDRIAL RIBOSOMAL-PROTEIN

The nuclear gene MRP10 of Saccharomyces cerevisiae was cloned by compl ementation of a respiratory deficient mutant N518/L1. This mutant is d efective in mitochondrial translation and shows a tendency to accumula te deletions in mitochondrial DNA (rho(-)). Analysis revealed Mrp10p t o be a component of the 37 S subunit of the mitochondrial ribosomes. D isruption of MRP10 in a haploid strain of yeast elicits a phenotype id entical to that of the original mutant. The respiratory defect of the null mutant is rescued by re-introducing the MRP10 gene in a wild-type mitochondrial DNA background. These results indicate that Mrp10p belo ngs to the class of yeast mitochondrial ribosomal proteins that are es sential for translation. Searches of current databases failed to revea l any homologs among known bacterial or eucaryotic cytoplasmic ribosom al proteins. Some sequence similarity, however, was detected between M rp10p and Ym137p, previously identified as a component of the yeast mi tochondrial 50 S ribosomal subunit.