A third essential DNA polymerase in S. cerevisiae

Cell. 1990 Sep 21;62(6):1143-51. doi: 10.1016/0092-8674(90)90391-q.


DNA polymerases I and III are essential for viability of S. cerevisiae. We have cloned and analyzed POL2, the gene encoding the catalytic subunit of the third nuclear DNA polymerase, DNA polymerase II. POL2 expressed a transcript of approximately 7.5 kb and contained a reading frame that encoded a protein of calculated Mr 255,649. The N-terminal half of the predicted protein displayed relatively weak similarity of sequence to eukaryotic DNA polymerases. Disruption of the coding sequence at midpoint led to viable, slowly growing cells, which yielded a truncated polypeptide with DNA polymerase II activity, free from subunits B or C. Deletion of the reading frame resulted in inviability and the dumbbell terminal morphology that typically follows arrest of DNA replication. We conclude that three DNA polymerases are essential in yeast and argue that all three are replicases, a possibility that challenges existing models of eukaryotic DNA replication.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA Polymerase II / genetics*
  • DNA Polymerase II / isolation & purification
  • DNA Polymerase II / metabolism
  • Gene Library
  • Herpesvirus 4, Human / enzymology
  • Herpesvirus 4, Human / genetics
  • Molecular Sequence Data
  • Molecular Weight
  • Mutation
  • Oligonucleotide Probes
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / physiology
  • Sequence Homology, Nucleic Acid
  • Spores, Fungal / physiology


  • Oligonucleotide Probes
  • DNA Polymerase II

Associated data

  • GENBANK/M36724
  • GENBANK/M60416