A PMR2 tandem repeat with a modified C-terminus is located downstream from the KRS1 gene encoding lysyl-tRNA synthetase in Saccharomyces cerevisiae

Abstract

The KRS1 gene encodes the cytoplasmic form of Saccharomyces cerevisiae lysyl-tRNA synthetase. The KRS1 locus has been characterized. The lysyl-tRNA synthetase gene is unique in the yeast genome. The gene is located on the right arm of chromosome IV and disruption of the open reading frame leads to lethality. These results contrast with the situation encountered in Escherichia coli where lysyl-tRNA synthetase is coded by two distinct genes, lysS and lysU, and further address the possible biological significance of this gene duplication. The nucleotide sequence of the 3'-flanking region has been established. It encodes a long open reading frame whose nucleotide and amino acid structures are almost identical to PMR2, a cluster of tandemly repeated genes coding for P-type ion pumps. The sequence alterations relative to PMR2 are mainly located at the C-terminus of the protein.