Kaasch M, Kaasch J, Quiñones A
Wissenschaftsbereich Genetik, Martin-Luther-Universität, Halle/Saale, German Democratic Republic.
Mol Gen Genet. 1989 Oct;219(1-2):187-92. doi: 10.1007/BF00261175.
The dnaN and dnaQ genes encode the beta subunit and the epsilon subunit of the DNA polymerase III holoenzyme. Using translational fusions to lacZ we found that DNA damage caused by mitomycin C induces expression of the dnaA and dnaQ genes. This induction was not observed in lexA and recA mutants which block the induction of the SOS response, suggesting a relationship between the mechanism(s) of genetic control of DNA polymerase III holoenzyme and the SOS regulatory network. Nevertheless, there is evidence that the mitomycin C induction of dnaN and dnaQ is not a simple lexA-regulated process, because nalidixic acid (an excellent SOS inducer) does not increase dnaN and dnaQ gene expression, and the time course of induction is abnormally slow.
dnaN基因和dnaQ基因分别编码DNA聚合酶III全酶的β亚基和ε亚基。利用与lacZ的翻译融合，我们发现丝裂霉素C引起的DNA损伤会诱导dnaA基因和dnaQ基因的表达。在阻断SOS应答诱导的lexA和recA突变体中未观察到这种诱导现象，这表明DNA聚合酶III全酶的遗传控制机制与SOS调控网络之间存在关联。然而，有证据表明丝裂霉素C对dnaN和dnaQ的诱导并非简单的lexA调控过程，因为萘啶酸（一种出色的SOS诱导剂）并不会增加dnaN和dnaQ基因的表达，而且诱导的时间进程异常缓慢。
