Budd M, Mortimer R K
Radiat Res. 1984 Sep;99(3):582-90.
Previous results [M. Budd and R. K. Mortimer, Mutat. Res. 103, 19-24 (1982)] have shown that rad54-3 strains are temperature conditional for double-strand break repair. At the temperature where survival is high, 23 degrees C, rad54-3 strains are able to repair X-ray-induced double-strand breaks, while at the temperature where survival is low, 36 degrees C, these strains are unable to repair rad54-3 strains provide a system to study the effects of drugs that block protein synthesis such as cycloheximide on repair of X-ray damage. Repair of X-ray damage is studied by irradiating rad54-3 cells, incubating them at the permissive temperature, 23 degrees C, for 5 hr, shifting the cells to the restrictive temperature, 36 degrees C, and assaying for colony-forming ability. Comparing the survival of these cells with those which had been continuously incubated at the restrictive temperature after irradiation shows the extent of repair. Addition of cycloheximide at the time of irradiation causes an inhibition of repair. If cycloheximide is added a short time after irradiation, an enhanced recovery is observed compared with the addition of the drug at the time of irradiation. One explanation for the enhanced recovery is an increased synthesis of repair enzymes after irradiation.
先前的研究结果[M. 巴德和R. K. 莫蒂默，《突变研究》103，19 - 24(1982)]表明，rad54 - 3菌株在双链断裂修复方面存在温度依赖性。在存活率较高的温度（23摄氏度）下，rad54 - 3菌株能够修复X射线诱导的双链断裂，而在存活率较低的温度（36摄氏度）下，这些菌株无法进行修复。rad54 - 3菌株提供了一个系统，用于研究诸如环己酰亚胺等阻断蛋白质合成的药物对X射线损伤修复的影响。通过对rad54 - 3细胞进行辐照，在允许温度（23摄氏度）下孵育5小时，将细胞转移到限制温度（36摄氏度），并检测集落形成能力，来研究X射线损伤的修复情况。将这些细胞的存活率与辐照后在限制温度下持续孵育的细胞的存活率进行比较，可显示修复的程度。在辐照时添加环己酰亚胺会导致修复受到抑制。如果在辐照后短时间内添加环己酰亚胺，与在辐照时添加该药物相比，会观察到恢复增强。恢复增强的一种解释是辐照后修复酶的合成增加。
