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′ → 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 (α), II (ε), or III (δ). 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 β.
Purification and characterization of a new DNA polymerase from budding yeast Saccharomyces cerevisiae. A probable homolog of mammalian DNA polymerase beta / K. Shimizu, C. Santocanale, P. A. Ropp, M. P. Longhese, P. Plevani, G. Lucchini, A. Sugino. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 268:36(1993 Dec 25), pp. 27148-53-27153.
Purification and characterization of a new DNA polymerase from budding yeast Saccharomyces cerevisiae. A probable homolog of mammalian DNA polymerase beta
P. Plevani;
1993
Abstract
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′ → 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 (α), II (ε), or III (δ). 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 β.Pubblicazioni consigliate
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