Zaboĭkin M M, Alekhina R P, Likhtenshteĭn A V
Vopr Med Khim. 1991 Nov-Dec;37(6):39-44.
Intact cell nuclei (or whole cell lysates) were immobilized on Celite and extracted gradually with gradients of NaCl, LiCl-urea and temperature. Contrary to the notion of DNA integrity and continuity within chromosomes, a heterogeneous spectrum of DNA fragments of large size was obtained, adhesion of which to the nuclear interior widely varied. Similar chromatographic patterns of DNA were observed in analysis of various origin cells both in normal animal tissues and in malignant cells (Djungarian hamster fibroblasts transformed by SV40). Possible artefacts of apparent genome fragmentation caused by radioactive precursors or hydrodynamic shearing were checked up and ruled out as well as endogenous nucleases appear not to be involved in the phenomenon observed. DNA end-labelling in situ enabled to reveal pre-existence of DNA fragments in isolated nuclei.
完整的细胞核（或全细胞裂解物）固定在硅藻土上，并用氯化钠、氯化锂 - 尿素梯度溶液及温度进行逐步提取。与染色体中DNA完整性和连续性的概念相反，得到了一系列大小各异的DNA片段，其与核内部的黏附情况差异很大。在对正常动物组织和恶性细胞（经SV40转化的田鼠仓鼠成纤维细胞）中各种来源细胞的分析中，观察到了类似的DNA色谱模式。对由放射性前体或流体动力学剪切导致的明显基因组片段化的可能假象进行了检查并排除，同时也排除了内源性核酸酶参与所观察到的现象。原位DNA末端标记能够揭示分离细胞核中DNA片段的预先存在。
