Study on UV-induced protease of hunam cells

为了研究蛋白酶活性在人体细胞对254 nm紫外光反应中的作用，有必要对蛋白酶进行纯化。因此，在本研究中，我们试图建立具有高水平的紫外线诱导的蛋白酶活性的细胞株。由于人干扰素预处理的RSa细胞在紫外线照射前有明显的诱导作用，而人干扰素预处理的RSa细胞在紫外线照射前有明显的蛋白酶活性，且蛋白酶抑制剂之一的抗痛素对蛋白酶活性有特异性抑制作用，因此，在紫外线照射后立即用低剂量的抗痛素处理RSa细胞，克隆了存活细胞。经紫外线照射后，存活的细胞显示出高水平的蛋白酶活性，并且诱导的蛋白酶活性再次被抗痛剂抑制。除了变异细胞外，已经建立的干扰素抗性细胞在UV照射后也表现出蛋白酶诱导。与其亲本RSa细胞的超突变性相比，这两种变异细胞都表现出低突变性。此外，在经UV照射的变异细胞中观察到比亲本细胞更多的DNA排斥能力。提示蛋白酶活性在UV后的早期步骤中对人类细胞的无错误功能起作用。

In order to study the role of protease activity in tesponse of human cells to 254 nm for-ultraviolet light it will be necessary to purify the protease. Therefore, in the present study we attempted to establish cell strains with high levels of UV-induced protease activity. As the induction was observed in RSa cells pretreated with human interferon prior to UV and the protease activity was cells pretreated with human interferon prior to UV and the protease actibity was specifically ingibited by antipain, one of proteasw inhibitors, form RSa cells treated with low deses of antipain immediately after UV asurvival cells were cloned. The survival cells showed high levels protease activity after UV iffadiation and the induced protease activity was again inhibited by antipain. Inaddition to the vatiant cells already-established interferon-resistant cells also showed protease inducibility after UV.Both the variants appeared hypomutable in contrast to hypermuability of their parent RSa cells Furthermore, more increased DNA-repir capacity was observed in the variant cells inrradiated with UV than in the parent cells.Thus, it was suggested that the protease activity play a role in error-free functions of human cells in early steps after UV.