Yatagai F, Glickman B W
Mutat Res. 1986 Dec;163(3):209-24. doi: 10.1016/0027-5107(86)90019-9.
We have studied the specificity of mutation induced by PUVA treatment in the lacI gene of E. coli. Cells were exposed to near UV (approximately 365 nm) in the presence of 8-methoxypsoralen under conditions yielding about 7% survival and a 10-fold increase in mutation frequency. The cloning and sequencing of 131 mutants recovered following PUVA treatment revealed that almost all classes of mutation including base substitutions, frameshifts and deletions were induced. The distribution of mutations was non-random and a region of the lacI gene was found to be virtually silent for all classes of mutation. Intriguingly, the broad spectrum of mutation is accompanied by the recovery of mutation at two spontaneous hotspots. We observed a 7-fold increase at a frameshift hotspot involving the gain or loss of a tetramer tandemly repeated 3 times at this site and a 23-fold increase at an A:T----G:C transition hotspot located at the +6 mutational spectrum recovered following PUVA treatment was unique and a detailed analysis of the different classes of mutations indicates a role for DNA repair of both monoadducts and cross-links in the production of mutation.
我们研究了补骨脂素紫外线A（PUVA）处理诱导的大肠杆菌lacI基因突变的特异性。在存在8-甲氧基补骨脂素的情况下，将细胞暴露于近紫外线（约365nm），条件是存活率约为7%，突变频率增加10倍。对PUVA处理后回收的131个突变体进行克隆和测序表明，几乎所有类型的突变都被诱导，包括碱基替换、移码突变和缺失。突变分布是非随机的，并且发现lacI基因的一个区域对所有类型的突变几乎都是沉默的。有趣的是，广泛的突变伴随着两个自发热点处突变的恢复。我们观察到一个移码热点处增加了7倍，该热点涉及在此位点串联重复3次的四聚体的增减，以及位于+6处的A:T向G:C转换热点处增加了23倍。PUVA处理后恢复的突变谱是独特的，对不同类型突变的详细分析表明，单加合物和交联的DNA修复在突变产生中起作用。
