The initiation of nuclear DNA synthesis has been studied in cytochalasin B (CB)-induced binucleate human diploid fibroblasts (WI-38 cells). Mitotic cells from different passage levels were rendered binucleate by a brief pulse of CB. The cells were then washed free of the drug, and DNA synthesis was studied by [3H]thymidine labeling. The results showed that, in a small percentage of binucleate cells, one nucleus was labeled (S phase) and the other nucleus was unlabeled (G1 phase). There was no significant difference in the percentage of these cells with increasing passage levels. The results of this study suggest that some WI-38 cells retire from the cell cycle at different passage levels, and thereby become refractory to inducers of nuclear DNA synthesis generated by sister cells in S phase.
Article| May 01 1981
Cell population heterogeneity in the inducibility of DNA synthesis in human diploid fibroblasts.
M V Rao
Online Issn: 1540-8140
Print Issn: 0021-9525
J Cell Biol (1981) 89 (2): 194–197.
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M V Rao; Cell population heterogeneity in the inducibility of DNA synthesis in human diploid fibroblasts.. J Cell Biol 1 May 1981; 89 (2): 194–197. doi: https://doi.org/10.1083/jcb.89.2.194
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