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Updated: Sep 20, 2026

Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
Published on: August 21, 2021
Folate- and deoxyuridine-sensitive chromatid breakage may result from DNA repair during G2
1Division of Environmental Health Laboratory Sciences, Centers for Disease Control, Atlanta, GA 30333.
Abstract:
A substantial increase in chromosome breakage was seen in proliferating human lymphocytes treated with 1-beta-D-arabinofuranosyl cytosine (cytosine arabinoside, cytarabine, araC) during the last 2 h of culture. The increase was larger in low folate media than in high folate media and larger still in low folate media supplemented by deoxyuridine. Similar results were found when cells were exposed to aphidicolin for the last 2 h of culture. The results provide additional evidence that folate-sensitive chromosome breakage is a consequence of abnormal DNA synthesis (in particular incorporation of deoxyuridine) and subsequent attempts during G2 to repair the abnormal DNA.
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