TY - JOUR
T1 - Linking uracil base excision repair and 5-fluorouracil toxicity in yeast
AU - Seiple, Lauren
AU - Jaruga, Pawel
AU - Dizdaroglu, Miral
AU - Stivers, James T.
N1 - Funding Information:
We thank Drs Serge Boiteux, Jef Boeke and Xuewen Pan for providing yeast strains and for invaluable advice. We also thank Daniel J. Krosky for his helpful suggestions. This work was supported by NIH grant GM56834-10 (to J.T.S). The Open Access publication charges for this article have been waived by Oxford University Press.
PY - 2006/1
Y1 - 2006/1
N2 - 5-fluorouracil (5-FU) is a widely used anticancer drug that disrupts pyrimidine nucleotide pool balances and leads to uracil incorporation in DNA, which is then recognized and removed by the uracil base excision repair (BER) pathway. Using complementary biochemical and genetic approaches we have examined the role of uracil BER in the cell killing mechanism of 5-FU. A yeast strain lacking the enzyme uracil DNA glycosylase (Ung1), which excises uracil from the DNA backbone leaving an abasic site, showed significant protection against the toxic effects of 5-FU, a G1/S cell cycle arrest phenotype, and accumulated massive amounts of U/A base pairs in its genome (∼4% of T/A pairs were now U/A). A strain lacking the major abasic site endonuclease of Saccharomyces cerevisiae (Apn1) showed significantly increased sensitivity to 5-FU with G2/M arrest. Thus, efficient processing of abasic sites by this enzyme is protective against the toxic effects of 5-FU. However, contrary to expectations, the Apn1 deficient strain did not accumulate intact abasic sites, indicating that another repair pathway attempts to process these sites in the absence Apn1, but that this process has catastrophic effects on genome integrity. These findings suggest that new strategies for chemical intervention targeting BER could enhance the effectiveness of this widely used anticancer drug.
AB - 5-fluorouracil (5-FU) is a widely used anticancer drug that disrupts pyrimidine nucleotide pool balances and leads to uracil incorporation in DNA, which is then recognized and removed by the uracil base excision repair (BER) pathway. Using complementary biochemical and genetic approaches we have examined the role of uracil BER in the cell killing mechanism of 5-FU. A yeast strain lacking the enzyme uracil DNA glycosylase (Ung1), which excises uracil from the DNA backbone leaving an abasic site, showed significant protection against the toxic effects of 5-FU, a G1/S cell cycle arrest phenotype, and accumulated massive amounts of U/A base pairs in its genome (∼4% of T/A pairs were now U/A). A strain lacking the major abasic site endonuclease of Saccharomyces cerevisiae (Apn1) showed significantly increased sensitivity to 5-FU with G2/M arrest. Thus, efficient processing of abasic sites by this enzyme is protective against the toxic effects of 5-FU. However, contrary to expectations, the Apn1 deficient strain did not accumulate intact abasic sites, indicating that another repair pathway attempts to process these sites in the absence Apn1, but that this process has catastrophic effects on genome integrity. These findings suggest that new strategies for chemical intervention targeting BER could enhance the effectiveness of this widely used anticancer drug.
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U2 - 10.1093/nar/gkj430
DO - 10.1093/nar/gkj430
M3 - Article
C2 - 16407331
AN - SCOPUS:31644442238
SN - 0305-1048
VL - 34
SP - 140
EP - 151
JO - Nucleic acids research
JF - Nucleic acids research
IS - 1
ER -