title: Effect of a dCTP:dTTP pool imbalance on DNA replication fidelity in Friend murine erythroleukemia cells.
abstract: Nucleotide pool imbalances have been reported to affect the fidelity of DNA replication and repair in prokaryotic and eukaryotic cells. We have reported previously that the mutagen-hypersensitive thymidine kinase (TK)-deficient Friend erythroleukemia (FEL) cells (subclones 707BUF and 707BUE), have a more than sixfold increase in the dCTP:dTTP pool ratio when compared to that of wild-type, TK-positive (TK(+)) clone 707 cells. In this study we present the results of an investigation of the effect of the dCTP:dTTP pool imbalance on the accuracy of DNA replication within 707BUF cells. We examined the spontaneous mutation spectra occurring at the adenine phosphoribosyltransferase (aprt) locus within clone 707 (TK(+)) and 707BUF (TK(-)) FEL cells. Mutations recovered at the aprt locus in FEL cells comprised: base substitutions (43:73), frameshifts (14:13.5), and deletions (43:13.5) [clone 707 (TK(+)):707BUF (TK(-)), respectively, expressed as percentages]. A comparison of the mutation spectra obtained for the two cell lines did not reveal any significant increase in misincorporation of dCTP, the nucleotide in excess, in 707BUF (TK(-)) cells, during DNA replication synthesis. These data suggest that the dCTP:dTTP pool imbalance does not alter the fidelity of DNA replication synthesis in 707BUF (TK(-)) FEL cells. Rather, the predominance of GC --> AT transitions (53%) in the 707BUF (TK(-)) spectrum may reflect a reduced efficiency of repair by uracil DNA glycosylase of uracil residues within these cells.
authors.affiliation: School of Clinical Dentistry, The Queen's University of Belfast, Belfast, Northern Ireland.
authors.forename: P L
authors.initials: PL
authors.lastname: Hyland
authors.forename: A L
authors.initials: AL
authors.lastname: Keegan
authors.forename: M D
authors.initials: MD
authors.lastname: Curran
authors.forename: D
authors.initials: D
authors.lastname: Middleton
authors.forename: P G
authors.initials: PG
authors.lastname: McKenna
authors.forename: Y A
authors.initials: YA
authors.lastname: Barnett
mesh_terms: D000228:Adenine Phosphoribosyltransferase / Q000235:genetics; D000818:Animals; D002999:Clone Cells; D004252:DNA Mutational Analysis / Q000379:methods; D004261:DNA Replication / Q000235:genetics*; D003845:Deoxycytosine Nucleotides / Q000235:genetics / Q000378:metabolism*; D005091:Exons; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D018807:Polymorphism, Single-Stranded Conformational; D017422:Sequence Analysis, DNA; D013937:Thymidine Kinase / Q000172:deficiency / Q000235:genetics; D013942:Thymine Nucleotides / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D003845:Deoxycytosine Nucleotides; D013942:Thymine Nucleotides; C024107:2'-deoxycytidine 5'-triphosphate; D000228:Adenine Phosphoribosyltransferase; D013937:Thymidine Kinase; C024157:thymidine 5'-triphosphate