title: SCE induction is proportional to substitution in DNA for thymidine by CldU and BrdU.
abstract: The incorporation of 5-bromo- and 5-chlorodeoxyuridine into cellular DNA and the induction of sister-chromatid exchanges (SCE) was examined with Chinese hamster ovary cells in culture. Although CldU caused 3-5 times more SCE than BrdU at equal extracellular concentrations, the 2 analogs were incorporated into DNA in place of thymidine similarly over a concentration range of 0.5-20 microM. The results show that SCE induction is linearly proportional to substitution for thymidine by both BrdU and CldU. Finally, based on linear extrapolation, a spontaneous level of approximately 6 SCEs per cell is estimated.
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology*; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D003434:Crossing Over, Genetic / Q000187:drug effects*; D004247:DNA / Q000235:genetics*; D003857:Deoxyuridine / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D010053:Ovary; D012854:Sister Chromatid Exchange / Q000187:drug effects*; D013936:Thymidine
chemical_list: C012244:5-chloro-2'-deoxyuridine; D004247:DNA; D001973:Bromodeoxyuridine; D013936:Thymidine; D003857:Deoxyuridine