Balajee A S, Natarajan A T
MGC Department of Radiation Genetics and Chemical Mutagenesis, University of Leiden, The Netherlands.
Mutat Res. 1993 May;302(1):25-31. doi: 10.1016/0165-7992(93)90086-b.
Restriction endonucleases (REs) AluI, EcoRI, MspI, PvuII and SmaI were introduced into exponentially growing Chinese hamster ovary (CHO) cells permeabilised by the bacterial cytotoxin, streptolysin O (SLO). Sister-chromatid exchanges (SCEs) were scored in posttreatment metaphases following recovery times of 20 and 24 h. At both fixation times, all five REs tested were found to increase the frequencies of SCEs compared with that of SLO-treated controls. Among the REs used, AluI and PvuII were found to be most effective, inducing on average a 2-3-fold increase, with a proportion of cells exhibiting more than 80 SCEs. These results confirm the earlier findings of Natarajan et al. (1985) and tend to suggest that double-strand breaks (DSBs) induced by REs are involved in the formation of SCEs.
将限制性内切酶AluI、EcoRI、MspI、PvuII和SmaI导入经细菌细胞毒素链球菌溶血素O（SLO）通透处理的处于指数生长期的中国仓鼠卵巢（CHO）细胞中。在恢复20小时和24小时后的处理后中期对姐妹染色单体交换（SCE）进行计数。在两个固定时间点，与SLO处理的对照组相比，发现所测试的所有五种限制性内切酶均增加了SCE的频率。在所使用的限制性内切酶中，发现AluI和PvuII最有效，平均诱导增加2至3倍，有一部分细胞表现出超过80次SCE。这些结果证实了Natarajan等人（1985年）的早期发现，并倾向于表明限制性内切酶诱导的双链断裂（DSB）参与了SCE的形成。
