Cremer C, Cremer T
Mutat Res. 1986 Oct;163(1):33-40. doi: 10.1016/0027-5107(86)90055-2.
Cells of synchronized and of asynchronously growing cultures of a V79 Chinese hamster line were microirradiated with a low power laser-UV-microbeam of wavelength 257 nm. Ultraviolet light was either focused onto a small part of the nucleus (mode I) or distributed over the whole nucleus (mode II). Following microirradiation, the cells were incubated for 7-20 h with caffeine (1-2 mM) until chromosome preparation was performed. After both modes of microirradiation, shattering of the entire chromosome complement (generalized chromosome shattering, GCS) was observed. It is suggested that the probability by which GCS is induced depends on the total number of DNA lesions rather than on their distribution in the chromatin. The results are consistent with the prediction of a "factor depletion model" which assumes that in a given cell, GCS takes place both in irradiated and non-irradiated chromosomes if the total number of daughter strand-repair sites surpasses a threshold value.
用波长为257nm的低功率激光-紫外微束对V79中国仓鼠系同步生长和异步生长培养物的细胞进行微辐照。紫外光要么聚焦在细胞核的一小部分上（模式I），要么分布在整个细胞核上（模式II）。微辐照后，将细胞与咖啡因（1-2mM）孵育7-20小时，直到进行染色体制备。在两种微辐照模式后，均观察到整个染色体组的破碎（广义染色体破碎，GCS）。有人提出，诱导GCS的概率取决于DNA损伤的总数，而不是它们在染色质中的分布。这些结果与“因子耗竭模型”的预测一致，该模型假设在给定的细胞中，如果子链修复位点的总数超过阈值，则GCS会在辐照和未辐照的染色体中发生。
