Giocanti N, Sabattier R, Ekert B
Institut Curie, Section de Biologie, Centre universitaire, Orsay.
C R Acad Sci III. 1989;308(7):189-94.
Nucleoid sedimentation analysis was applied to the study of DNA supercoiling repair in cultured FR 3T3 fibroblasts exposed to low doses of fast neutrons or gamma-rays. Supercoiling was fully restored in both instances upon post-irradiation at 37 degrees C, but the rate of repair of neutron-induced lesions was lower than that for gamma-rays. Non-repairable breaks were not evidenced at the neutral pH used. We suggest that the non-repairable alkali-labile sites evidenced by others in neutron-irradiated DNA do not prevent strand break rejoining and subsequent recovery of the tertiary DNA structure.
将类核沉降分析应用于对暴露于低剂量快中子或γ射线的培养FR 3T3成纤维细胞中DNA超螺旋修复的研究。在这两种情况下，经37℃辐照后超螺旋均完全恢复，但中子诱导损伤的修复速率低于γ射线诱导损伤的修复速率。在所使用的中性pH条件下未发现不可修复的断裂。我们认为，其他人在中子辐照DNA中所证实的不可修复的碱不稳定位点并不妨碍链断裂的重新连接及随后三级DNA结构的恢复。
