Iseki S
Exp Cell Res. 1986 Dec;167(2):311-26. doi: 10.1016/0014-4827(86)90172-2.
The nick-translation procedure without external addition of DNase was performed in situ on sections of various rat organs to detect possible DNA single-strand breaks (nicks) in normal tissues. The freshly frozen sections were briefly fixed in ethanol/acetone and nick-translated in the presence of E. coli DNA polymerase I. A significant difference in the amount of nuclear reaction was found among the different cell populations as detected by autoradiography following incorporation of tritiated TTP as well as by histochemical staining following incorporation of biotin-dUTP into nuclei. Such incorporation of triphosphates was localized in the DNA and was entirely dependent on E. coli DNA polymerase I. The nuclei with the highest reactivity were found in skeletal muscle cells, lymphocytes in various lymphatic organs, the proliferative cells in the gastrointestinal tract, stratified squamous epithelial cells, duct epithelial cells of salivary gland and the maturing spermatids in the seminiferous tubules. These results suggest that, under the conditions adopted, the cells in various tissues reveal different chromatin structures resulting in varying rates of nick translation reaction. Such difference(s) in chromatin structure, presumably including that in the number of DNA single-strand breaks or in the level of endogenous nuclease activity, may be associated with the mechanisms involved in cell growth and differentiation.
在不额外添加脱氧核糖核酸酶（DNase）的情况下，对各种大鼠器官切片进行原位切口平移操作，以检测正常组织中可能存在的DNA单链断裂（切口）。将新鲜冷冻切片在乙醇/丙酮中短暂固定，然后在大肠杆菌DNA聚合酶I存在的情况下进行切口平移。通过掺入氚标记的三磷酸胸苷（TTP）后进行放射自显影以及将生物素化的脱氧尿苷三磷酸（biotin-dUTP）掺入细胞核后进行组织化学染色检测发现，不同细胞群体之间的核反应量存在显著差异。这种三磷酸酯的掺入定位于DNA中，并且完全依赖于大肠杆菌DNA聚合酶I。反应性最高的细胞核存在于骨骼肌细胞、各种淋巴器官中的淋巴细胞、胃肠道中的增殖细胞、复层鳞状上皮细胞、唾液腺导管上皮细胞以及生精小管中的成熟精子细胞中。这些结果表明，在所采用的条件下，各种组织中的细胞显示出不同的染色质结构，导致切口平移反应速率不同。这种染色质结构的差异，大概包括DNA单链断裂的数量或内源性核酸酶活性水平的差异，可能与细胞生长和分化所涉及的机制有关。
