Cleaver J E, Thomas G H, Park S D
Biochim Biophys Acta. 1979 Aug 29;564(1):122-31. doi: 10.1016/0005-2787(79)90193-x.
Human cells (normal and xeroderma pigmentosum variant) irradiated with ultraviolet light and pulse-labelled with [3H]thymidine underwent transient decline and recovery of molecular weights of newly synthesized DNA and rates of [3H]thymidine incorporation. The ability to synthesize normal-sized DNA recovered more rapidly in both cell types than thymidine incorporation. During recovery cells steadily increased in their ability to replicate normal-sized DNA on damaged templates. The molecular weight versus time curves fitted exponential functions with similar rate constants in normal and heterozygous xeroderma pigmentosum cells, but with a slower rate in two xeroderma pigmentosum variant cell lines. Caffeine added during the post-irradiation period eliminated the recovery of molecular weights in xeroderma pigmentosum variant but not in normal cells. The recovery of the ability to synthesize normal-sized DNA represents a combination of a number of cellular regulatory processes, some of which are constitutive, and one of which is altered in the xeroderma pigmentosum variant such that recovery becomes slow and caffeine sensitive.
用紫外线照射并用[3H]胸苷脉冲标记的人类细胞（正常细胞和着色性干皮病变异细胞），新合成DNA的分子量和[3H]胸苷掺入率经历了短暂下降和恢复。在两种细胞类型中，合成正常大小DNA的能力比胸苷掺入的恢复速度更快。在恢复过程中，细胞在受损模板上复制正常大小DNA的能力稳步提高。分子量与时间曲线在正常细胞和杂合性着色性干皮病细胞中拟合指数函数，速率常数相似，但在两种着色性干皮病变异细胞系中速率较慢。照射后添加咖啡因消除了着色性干皮病变异细胞中分子量的恢复，但在正常细胞中没有。合成正常大小DNA能力的恢复代表了许多细胞调节过程的组合，其中一些是组成性的，其中一个在着色性干皮病变异细胞中发生改变，使得恢复变得缓慢且对咖啡因敏感。
