Abstract
Excision repair of bulky chemical adducts in alpha DNA of confluent cultures of African green monkey cells has previously been shown to be deficient relative to that in the overall genome. We have compared the removal of adducts produced by treatment with aflatoxin B 1 (AFB 1) and N-acetoxy-2-acetylaminofluorene (NA-AAF) from alpha DNA sequences in synchronized and exponentially and exponentially growing cultures of monkey cells. Proficient removal of AFB 1 adducts in alpha DNA was observed in exponentially growing cultures. However, as the cultures approached confluence, adduct removal from alpha DNA became deficient. Cells synchronized by subculturing confluent cultures exhibited proficient removal of adducts from both alpha and bulk DNA when treated in early G 1 or late S/G 2 while those cells treated in early S phase did not remove adducts from either alpha or bulk DNA. We conclude that the accessibility of chemical adducts to repair in alpha chromatin is influenced by the growth state and the cell cycle stage.
Published Version
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