Both replication bypass fidelity and repair efficiency influence the yield of mutations per target dose in intact mammalian cells induced by benzo[a,]pyrene-diol-epoxide and dibenzo[a,l]pyrene-diol-epoxide
Both replication bypass fidelity and repair efficiency influence the yield of mutations per target dose in intact mammalian cells induced by benzo[a,]pyrene-diol-epoxide and dibenzo[a,l]pyrene-diol-epoxide
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DOI：
10.1016/j.dnarep.2008.03.022
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发表时间：
2008-08-02
期刊：
影响因子：
3.8
通讯作者：
Jenssen, Dag
中科院分区：
文献类型：
--
作者：
Lagerqvist, Anne;Hakansson, Daniel;Jenssen, Dag
当在由反应性 PAH 代谢物（例如二醇环氧化物）形成的未修复 DNA 损伤上发生容易出错的 DNA 复制时，预计会产生由多环芳烃 (PAH) 引起的突变。两种PAH-二醇环氧化物的致突变性(+)-抗-7,8-二羟基-9,10-环氧-7,8,9,10-四氢苯并[a]芘(BPDE)和()-抗-11,12-二羟基-13,14-环氧-11,1 2,13,14-四氢二苯并[a,1]在核苷酸切除修复（NER）熟练和缺陷的仓鼠细胞系中比较了芘（DBPDE）。我们应用 32P 标记后测定来分析加合物水平，并应用 hprt 基因突变测定来监测突变。结果发现，在 NER 充足的细胞中，DBPDE 的每目标剂量的致突变性是 BPDE 的 4 倍，而在 NER 缺陷的细胞中，每目标剂量的致突变性是 BPDE 的 1.4 倍。为了研究NER熟练细胞中不同加合物的致突变性在多大程度上受到修复或复制旁路的影响，我们测量了总体NER切割率、加合物去除率、复制旁路率和hprt基因中诱导重组的频率。结果表明，在 NER 熟练细胞中，BPDE 损伤的 NER 效率比 DBPDE 损伤高 5 倍。然而，DBPDE 加合物更有效地阻断复制，并且在 bprt 基因中诱导的重组事件比 BPDE 加合物多 6 倍，这表明 DBPDE 加合物在更大程度上被同源重组绕过。这里获得的结果表明PAH的致突变性不仅受到NER的影响，而且还受到复制旁路保真度的影响。早些时候根据体外酶测定的结果推测了这一点，但现在在完整哺乳动物细胞的正向突变方面也得到了认可。 (c) 2008 Elsevier B.V. 保留所有权利。
Mutations induced by polycyclic aromatic hydrocarbons (PAH) are expected to be produced when error-prone DNA replication occurs across unrepaired DNA lesions formed by reactive PAH metabolites such as diol epoxides. The mutagenicity of the two PAH-diol epoxides (+) -an ti- 7,8- dihydroxy-9, 10- epoxy- 7,8,9, 10- tetrahydrobenzo [a] pyrene (BPDE) and () -anti - 11, 12 - dihydroxy- 13,14- epoxy- 11, 1 2,13,14-tetrahydro dibenzo [a, 1] pyrene (DBPDE) was compared in nucleotide excision repair (NER) proficient and deficient hamster cell lines. We applied the 32P-postlabelling assay to analyze adduct levels and the hprt gene mutation assay for monitoring mutations. It was found that the mutagenicity per target dose was 4 times higher for DBPDE compared to BPDE in NER proficient cells while in NER deficient cells, the mutagenicity per target dose was 1.4 times higher for BPDE. In order to investigate to what extent the mutagenicity of the different adducts in NER proficient cells was influenced by repair or replication bypass, we measured the overall NER incision rate, the rate of adduct removal, the rate of replication bypass and the frequency of induced recombination in the hprt gene. The results suggest that NER of BPDE lesions are 5 times more efficient than for DBPDE lesions, in NER proficient cells. However, DBPDE adducts block replication more efficiently and also induce 6 times more recombination events in the bprt gene than adducts of BPDE, suggesting that DBPDE adducts are, to a larger extent, bypassed by homologous recombination. The results obtained here indicate that the mutagenicity of PAH is influenced not only by NER, but also by replication bypass fidelity. This has been postulated earlier based on results using in vitro enzyme assays, but is now also being recognized in terms of forward mutations in intact mammalian cells. (c) 2008 Elsevier B.V. All rights reserved.