ENDONUCLEASE-IV OF ESCHERICHIA-COLI IS INDUCED BY PARAQUAT
ENDONUCLEASE-IV OF ESCHERICHIA-COLI IS INDUCED BY PARAQUAT
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DOI：
10.1073/pnas.84.10.3189
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发表时间：
1987-05-01
影响因子：
11.1
通讯作者：
WEISS, B
中科院分区：
文献类型：
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作者：
CHAN, E;WEISS, B
在大肠杆菌K-12的生长培养中加入百草枯(甲基紫精)，在1小时内使核酸内切酶IV的水平增加了10到20倍，核酸内切酶IV是一种无嘌呤/脱嘧啶的DNA酶。氯霉素可阻断这种诱导作用。白花蛇舌草素、甲萘二酮和吩嗪甲硫酸盐也增加了3倍或更多。过氧化氢使核酸内切酶IV的活性增加不超过2倍。链球菌素、呋喃妥因、叔丁基氢过氧化氢、γ-丙二醛等药剂无明显作用。紫外线、260 nm紫外线、甲烷磺酸甲酯、丝裂霉素C和抗坏血酸。百草枯、白花丹、甲苯二酮和吩嗪甲硫酸盐，或已知在体内通过氧化还原循环产生超氧阴离子。缺乏超氧化物歧化酶的突变株对百草枯的诱导异常敏感。此外，只需在纯氧中培养突变株即可诱导产生内切酶IV。未诱导或经百草枯处理的细胞中的核酸内切酶IV水平不受氧合酶基因突变的影响，氧合酶是一种可诱导的基因，控制着氧化应激调节基因。结果表明，核酸内切酶IV是一种可诱导的DNA修复酶，其诱导可能是通过产生超氧阴离子自由基来实现的。
The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H2O2 produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, .gamma. rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate or known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusally sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O2. The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H2O2-inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals.