In vivo species specificity of DNA polymerase alpha.
The DNA polymerase alpha enzymes from human, and budding (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are homologous proteins involved in initiation and replication of chromosomal DNA. Sequence comparison of human DNA polymerase alpha with that of S. cerevisiae and S. pombe shows overall levels of amino acid sequence identity of 32% and 34%, respectively. We report here that, despite the sequence conservation among these three enzymes, functionally active human DNA polymerase alpha fails to rescue several different conditional lethal alleles of the budding yeast POL1 gene at nonpermissive temperature. Furthermore, human DNA polymerase alpha cannot complement a null allele of budding yeast POL1 either in germinating spores or in vegetatively growing cells. In fission yeast, functionally active human DNA polymerase alpha is also unable to complement the disrupted pol alpha::ura4+ allele in germinating spores. Thus, in vivo, DNA polymerase alpha has stringent species specificity for initiation and replication of chromosomal DNA.
Francesconi
S
S
Department of Pathology, Stanford University School of Medicine, CA 94305.
Copeland
W C
WC
Wang
T S
TS
D000483:Alleles; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004256:DNA Polymerase I; D004257:DNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics; D005816:Genetic Complementation Test; D006801:Humans; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013696:Temperature
D005656:Fungal Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D004256:DNA Polymerase I; D004257:DNA Polymerase II; C083536:POL1 protein, S cerevisiae