Sen P, Hittelman W N
Mutat Res. 1984 Dec;129(3):359-64. doi: 10.1016/0027-5107(84)90090-3.
The purpose of these experiments was to determine the role of double-strand breaks in chromosome aberration formations. Quiescent normal human fibroblasts were treated with 3 microM nitrogen mustard and then allowed to repair their DNA damage for 24 h prior to cell fusion and induction of premature chromosome condensation. The extent of chromosome damage was determined in the G1 prematurely condensed chromosomes (G1 PCC). The presence of cytosine arabinoside and hydroxyurea during the repair period in order to accumulate single-strand DNA breaks resulted in an increase in the chromosome-break frequency. Treatment of these repair-inhibited cells with single-strand-specific neurospora endonuclease during fusion to change single-strand lesions into double-strand breaks resulted in a doubling of the aberration frequency. These results support the notion that double-strand breaks are important in chromosome-aberration formation.
这些实验的目的是确定双链断裂在染色体畸变形成中的作用。将静止的正常人成纤维细胞用3 microM氮芥处理，然后在细胞融合和诱导早熟染色体凝缩之前，让其修复DNA损伤24小时。在G1期早熟凝缩染色体（G1 PCC）中确定染色体损伤的程度。在修复期加入阿糖胞苷和羟基脲以积累单链DNA断裂，导致染色体断裂频率增加。在融合过程中用单链特异性脉孢菌内切酶处理这些修复受抑制的细胞，将单链损伤转变为双链断裂，导致畸变频率加倍。这些结果支持了双链断裂在染色体畸变形成中很重要这一观点。
