Rao M V
J Cell Biol. 1981 May;89(2):194-7. doi: 10.1083/jcb.89.2.194.
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.
在细胞松弛素B(CB)诱导的双核人二倍体成纤维细胞(WI-38细胞)中研究了核DNA合成的起始。来自不同传代水平的有丝分裂细胞通过短暂的CB脉冲处理变为双核细胞。然后将细胞洗涤以去除药物,并通过[3H]胸苷标记研究DNA合成。结果表明,在一小部分双核细胞中,一个细胞核被标记(S期),另一个细胞核未被标记(G1期)。随着传代水平的增加,这些细胞的百分比没有显著差异。这项研究的结果表明,一些WI-38细胞在不同传代水平退出细胞周期,从而对S期姐妹细胞产生的核DNA合成诱导剂变得不敏感。