Isolation and characterization of two Saccharomyces cerevisiae genes encoding homologs of the bacterial HexA and MutS mismatch repair proteins.
Homologs of the Escherichia coli (mutL, S and uvrD) and Streptococcus pneumoniae (hexA, B) genes involved in mismatch repair are known in several distantly related organisms. Degenerate oligonucleotide primers based on conserved regions of E. coli MutS protein and its homologs from Salmonella typhimurium, S. pneumoniae and human were used in the polymerase chain reaction (PCR) to amplify and clone mutS/hexA homologs from Saccharomyces cerevisiae. Two DNA sequences were amplified whose deduced amino acid sequences both shared a high degree of homology with MutS. These sequences were then used to clone the full-length genes from a yeast genomic library. Sequence analysis of the two MSH genes (MSH = mutS homolog), MSH1 and MSH2, revealed open reading frames of 2877 bp and 2898 bp. The deduced amino acid sequences predict polypeptides of 109.3 kD and 109.1 kD, respectively. The overall amino acid sequence identity with the E. coli MutS protein is 28.6% for MSH1 and 25.2% for MSH2. Features previously found to be shared by MutS homologs, such as the nucleotide binding site and the helix-turn-helix DNA binding motif as well as other highly conserved regions whose function remain unknown, were also found in the two yeast homologs. Evidence presented in this and a companion study suggest that MSH1 is involved in repair of mitochondrial DNA and that MSH2 is involved in nuclear DNA repair.
Reenan
R A
RA
Division of Cellular and Molecular Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Kolodner
R D
RD
D001483:Base Sequence; D002874:Chromosome Mapping; D004260:DNA Repair; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D005800:Genes, Fungal; D006801:Humans; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D051718:MutS Homolog 2 Protein; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C078660:MSH1 protein, S cerevisiae; D024101:Mitochondrial Proteins; D009838:Oligodeoxyribonucleotides; D029701:Saccharomyces cerevisiae Proteins; C489751:MSH2 protein, S cerevisiae; D051718:MutS Homolog 2 Protein