哺乳类细胞中易错修复诱导信号的初探

THE PRELIMINARY STUDY ON THE INDUCTORY SIGNAL TRIGGERING THE ERROR-PRONE DNA REPAIR FUNCTION IN MAMMALIAN CELLS

本研究从两个方面初探哺乳类细胞中易错修复诱导信号的本质:1.诱导信号是否产生于DNA损伤因子直接“击中”细胞中某些靶物质?2.DNA复制的抑制是否诱导信号的必要组成部分?用转染方法,把带有紫外线损伤的外源性DNA导入人和大鼠细胞,能像紫外线直接照射细胞一样诱发易错修复功能,而且两种诱导处理有着相似的剂量相应关系和动力学过程。再者,无论导入的DNA在细胞中能否起始复制,都具诱导功能。所以,可以认为,诱导信号来自DNA损伤本身而不是细胞中特定靶物质的损伤;DNA复制的抑制不是诱发易错修复的必要条件。

The nature of the signal triggering error-prone DNA repair functionin mammalian cells was studied from two notions: 1) Does the inducing signal resultfrom the direct hitting the cellular targets by DNA-damaging agents? 2) Is inhibitionof DNA replication a prerequisite condition for the triggering effect? Thus, the ult-raviolet (UV)-irradiated exogenous DNAs were introduced into human and rat cellsby transfection. The results showed that this transfection was able to induce the error--prone repair as efficient as direct UV-irradiation to cells. Mcreover, the two indu-ctory treatments expressed similar kinetics and dose-responses. No matter whether theintroduced DNAs initiated replication, they exbibited the inductory activity. Therefore,it can be considered that DNA lesions itself, not the direct interaction of DNA-dama-ging agents with specific cellular targets, serve as a triggering signal for the inductoryprocess. Inhibition of DNA replication is not a prerequisite for the inductory signal.