title: The periodic loss of metabolically unstable DNA during replication of chromosomal DNA of CHO cells.
abstract: The fate of 3H-thymidine incorporated into newly synthesized DNA of CHO cells was analyzed by either the estimation of the incorporated radioactivity per cell or sedimentation in alkaline sucrose gradient. Under conditions in which DNA synthesis proceeded continuously, the incorporated radioactivity was periodically lost and regained during a 90 min chase, corresponding to a cyclic change in the sedimentation profiles. When DNA synthesis was inhibited by hydroxyurea no cyclic change of the incorporated radioactivity was observed. The cyclic changes were regarded as the result of an actual metabolic change in 3H-labelled DNA probably joining to one of the newly formed sister strands of DNA and the loss of radioactivity seems to require active continued DNA synthesis.
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects; D005260:Female; D006918:Hydroxyurea / Q000633:toxicity; D007700:Kinetics; D010053:Ovary
chemical_list: D004247:DNA; D006918:Hydroxyurea