Pederson T
Proc Natl Acad Sci U S A. 1972 Aug;69(8):2224-8. doi: 10.1073/pnas.69.8.2224.
Pancreatic DNase I is used to probe the structure of chromatin isolated from synchronized HeLa cells. The degree to which DNA in chromatin is protected from DNase attack varies during the G(1), S, and G(2) phases of the cell cycle. In addition, the DNase sensitivity of chromatin from contact-inhibited African green monkey kidney cells differs from that of actively dividing, subconfluent cultures. These cell cycle-dependent chromatin changes were observed consistently at all enzyme concentrations (5000-fold range) and incubation times (15 min-2 hr) tested. The results indicate that the degree of complexing between DNA and chromosomal proteins changes during interphase, and they suggest that the chromosome coiling cycle of visible mitosis may extend in more subtle form over the entire cell cycle.
胰腺脱氧核糖核酸酶I用于探测从同步化的HeLa细胞中分离出的染色质结构。在细胞周期的G(1)、S和G(2)期，染色质中DNA免受脱氧核糖核酸酶攻击的程度有所不同。此外，接触抑制的非洲绿猴肾细胞的染色质对脱氧核糖核酸酶的敏感性与活跃分裂、未汇合培养的细胞不同。在所有测试的酶浓度（5000倍范围）和孵育时间（15分钟 - 2小时）下，均一致观察到这些依赖细胞周期的染色质变化。结果表明，DNA与染色体蛋白之间的复合程度在间期会发生变化，并且提示可见有丝分裂的染色体卷曲周期可能以更微妙的形式扩展至整个细胞周期。
