Hays J B, Lee E
Mol Gen Genet. 1985;201(3):402-8. doi: 10.1007/BF00331330.
The question of whether induction of the SOS response in Escherichia coli increases the efficiency of excision repair was addressed by measuring repair of UV-damaged nonreplicating lambda phage DNA in previously irradiated bacteria. Prior UV irradiation of lex+ bacteria enhanced both the rate of regeneration of infective phage DNA (about 10-fold) and the rate of cyclobutane dimer removal early in repressed infections. Indirect induction of SOS-regulated repair activities by the nonreplicating irradiated phage DNA itself seemed negligible. Prior bacterial irradiation reduced the frequency of recombination (loss of a tandem chromosomal duplication) of nonreplicating UV-irradiated DNA. In this respect UV-stimulated recombination of nonreplicating DNA differs from RecF-dependent recombination processes that are stimulated by increased SOS expression. Surprisingly, prior UV irradiation of lexA3 bacteria caused a small but reproducible increase in the regeneration of infective phage DNA.
通过测量先前受过辐照的细菌中紫外线损伤的非复制型λ噬菌体DNA的修复情况，研究了大肠杆菌中SOS应答的诱导是否会提高切除修复效率这一问题。lex+细菌先前受到紫外线照射，在受抑制感染早期，既提高了感染性噬菌体DNA的再生速率（约10倍），也提高了环丁烷二聚体的去除速率。非复制型受辐照噬菌体DNA本身对SOS调控的修复活性的间接诱导似乎可以忽略不计。细菌先前受到辐照会降低非复制型紫外线辐照DNA的重组频率（串联染色体重复的丢失）。在这方面，紫外线刺激的非复制型DNA重组不同于由SOS表达增加所刺激的RecF依赖性重组过程。令人惊讶的是，lexA3细菌先前受到紫外线照射，导致感染性噬菌体DNA的再生出现了虽小但可重复的增加。
