Section 10
Chapter 9,277

Purification and characterization of a new DNA polymerase from budding yeast Saccharomyces cerevisiae. A probable homolog of mammalian DNA polymerase beta

Shimizu, K.; Santocanale, C.; Ropp, P.A.; Longhese, M.P.; Plevani, P.; Lucchini, G.; Sugino, A.

Journal of Biological Chemistry 268(36): 27148-27153


ISSN/ISBN: 0021-9258
PMID: 8262953
Accession: 009276509

Download citation:  

A new DNA polymerase activity was identified and purified to near homogeneity from extracts of mitotic and meiotic cells of the yeast Saccharomyces cerevisiae. This activity increased at least 5-fold during meiosis, and it was shown to be associated with a 68-kDa polypeptide as determined by SDS-polyacrylamide gel electrophoresis. This new DNA polymerase did not have any detectable 3' fwdarw 5' exonuclease activity and preferred small gapped DNA as a template-primer. The activity was inhibited by dideoxyribonucleoside 5'-triphosphates and N-ethylmaleimide but not by concentrations of aphidicolin which completely inhibit either DNA polymerases I (alpha), II (epsilon), or III (delta). Since no polypeptide(s) in the extensively purified DNA polymerase fractions cross-reacted with antibodies raised against yeast DNA polymerases I, II, and III, we called this enzyme DNA polymerase IV. The DNA polymerase IV activity increased at least 10-fold in a yeast strain overexpressing the gene product predicted from the YCR14C open-reading frame (identified on S. cerevisiae chromosome III and provisionally called POLX), while no activity was detected in a strain where POLX was deleted. These results strongly suggest that DNA polymerase IV is encoded by the POLX gene and is a probable homolog of mammalian DNA polymerase beta.

PDF emailed within 1 workday: $29.90