The study of modulating effects on X-ray induced cell mutability by chaperons and SUMO.

我们以前曾报道过，人类血清因子对细胞突变性的调节与蛋白酶活性水平的增加有关。本工作旨在研究细胞突变性与分子伴侣如GRP 78、GRP 94、HSP 27和SUMO-3之间的关系。（1）GRP 94：通过X射线诱导的蛋白酶分析，其中一个伴侣蛋白GRP 94被确定为介导分子的候选基因。通过对GRP 94 mRNA进行siRNA的殖民地形成实验，提示GRP 94参与了细胞的X射线抗性。(2)We通过紫外诱导的蛋白酶分析，还鉴定了其他分子伴侣HSP 27。当抑制HSP 27的表达时，UV照射后去除6-4光产物的活性降低。我们进一步确定GRP 78也参与了UV诱导损伤的修复机制。因此，分子伴侣对细胞突变性的调节似乎是通过蛋白酶信号传导介导的。（3）SUMO-3是一种泛素样蛋白，被鉴定为X射线照射后DNA合成活性异常的候选基因。已知SUMO-3的功能受特定蛋白酶的调节。当SUMO-3表达降低时，X射线照射后DNA合成活性增加。我们表达了GFP-SUMO-3融合蛋白，并在X射线照射后观察到细胞核内明显的绿色荧光。一种新的检测人血清氧化应激的方法的应用。进行了通过评价血清氢过氧化物监测氧化应激的试验。部分患者和重度吸烟者血清过氧化氢水平高于健康志愿者。

We previously reported that modulation of cell mutability by human serum factors is associated with increased levels of protease activity. The present work is designed to examine the relationships between cell mutability and chaperons such as GRP78,GRP94,HSP27 and SUMO-3. : (1)GRP94 ; One of the chaperons, GRP94, was identified as a candidate gene for the mediator molecule by analysis of X-ray-induced protease. GRP94 was suggested to be involved in cellular X-ray resistance by the colony forming assay using siRNA for GRP94 mRNA.(2)We also identified other chaperons, HSP27, by analysis of UV-induced protease. The activity of removing 6-4 photo products after UV irradiation was decreased when expression of HSP27 was suppressed. We further identified that GRP78 is also involved in the repair mechanism for the UV-induced damage. Thus, the modulation of cell mutability by chaperons seems to be mediated though protease signaling.(3)One of ubiquitin-like proteins, SUMO-3, was identified as a candidate gene for abnormal DNA synthesis activity after X-ray irradiation. It is known that the function of SUMO-3 is regulated by specific proteases. The activity of DNA synthesis after X-ray irradiation was increased when expression of SUMO-3 was decreased. We expressed GFP-SUMO-3 fusion protein and observed a marked concentration of green fluorescence in the nuclear after X-ray irradiation.Application of a new method to evaluate oxidative stress in human serum. A test to monitor the oxidative stress by evaluating serum hydroperoxide was carried out. Serum hydrpperoxide of some patients and heavy-smokers showed higher levels than healthy volunteers.