Disruption of the MRP-L23 gene encoding the mitochondrial ribosomal protein L23 is lethal for Kluyveromyces lactis but not for Saccharomyces cerevisiae

Abstract

The Kluyveromyces lactis nuclear gene, MRP-L23, encodes a polypeptide of 155 amino acids that shares 70% and 43% identity to the ribosomal proteins L23 and L13 of Saccharomyces cerevisiae and Escherichia coli. The deduced protein, designated K1L23, is a likely component of the large subunit of mitochondrial ribosomes as it can complement the respiratory deficient phenotype of a S. cerevisiae mrp-L23 mutant. As in S. cerevisiae, KlMRP-L23 is essential for respiratory growth of K. lactis because disruption of the gene in a "petite-positive" strain carrying a rho o-lethality suppressor atp mutation rendered cells unable to grow on a nonfermentable carbon source. However, in contrast to S. cerev..