XRCC1 deficiency influences the cytotoxicity and the genomic instability induced by Me-lex, a specific inducer of N3-methyladenine.
XRCC1 deficiency influences the cytotoxicity and the genomic instability induced by Me-lex, a specific inducer of N3-methyladenine.
复制标题
DOI：
10.1016/j.dnarep.2010.03.016
复制
发表时间：
2010-07-01
期刊：
影响因子：
3.8
通讯作者：
Menichini P
中科院分区：
文献类型：
--
作者：
Russo D;Fronza G;Ottaggio L;Monti P;Perfumo C;Inga A;Iyer P;Gold B;Menichini P
Me-lex是一种序列特异性烷化剂，合成后优先（> 90%）在双链DNA的小沟中富含A-T的区域产生N3-甲基腺嘌呤（3-mA）。在本文中，我们研究了XRCC 1缺陷的影响，在处理3 mA加合物产生的Me-lex，通过分子分析的Hprt突变和细胞遗传学终点，如姐妹染色单体交换（SCE），微核（MN）和核碎裂的评价。缺乏XRCC 1活性的EM-C11细胞对Me-lex毒性的敏感性比DNA修复熟练的亲本CHO-9细胞高2.5倍，但不是超突变的。在EM-C11细胞中产生的Hprt基因座处的自发突变谱揭示了高百分比的基因组缺失。在Me-lex处理后，基因组缺失的百分比没有增加，但似乎靶向基因调控区的一类突变显著增加（p=0.0277），表明非编码Hprt基因组序列代表Me-lex诱导的罕见突变的强靶标。在50 µM Me-lex处理的CHO-9细胞中，每条染色体的SCE数量增加到背景值的3倍以上，而在更高的Me-lex浓度下，观察到MN和碎裂核的百分比急剧增加。在EM-C11细胞中，SCE的背景水平（0.939±0.182）比CHO-9（0.129±0.027）高约10倍，并且还发现了更高水平的多核细胞和MN。在EM-C11中，即使是低剂量的Me-lex（25µM）也会导致基因组损伤显著增加。这些结果表明，即使在没有外源性遗传毒性损伤和低水平的Me-lex诱导的损伤的情况下，XRCC 1缺陷也可导致基因组不稳定性，即，3 mA和/或BER中间值，会加剧这种不稳定性。
Me-lex is a sequence-specific alkylating agent synthesized to preferentially (> 90%) generate N3-methyladenine (3-mA) in the minor groove of double-strand DNA, in A-T rich regions. In this paper we investigated the effect of XRCC1 deficiency in the processing of 3-mA adducts generated by Me-lex, through the molecular analysis of the Hprt mutations and the evaluation of cytogenetic end points such as sister chromatid exchanges (SCEs), micronuclei (MN) and nucleus fragmentation. EM-C11 cells, deficient in XRCC1 activity, showed a 2.5-fold higher sensitivity to the toxicity of Me-lex compared to the DNA repair proficient parental CHO-9 cells, but were not hyper mutable. The spontaneous mutation spectrum at the Hprt locus generated in EM-C11 cells revealed a high percentage of genomic deletions. After Me-lex treatment, the percentage of genomic deletions did not increase, but a class of mutations which appeared to target regulatory regions of the gene significantly increased (p=0.0277), suggesting that non-coding Hprt genomic sequences represent a strong target for the rare mutations induced by Me-lex. The number of SCEs per chromosome increased 3-fold above background in 50 µM Me-lex treated CHO-9 cells, while at higher Me-lex concentrations a sharp increase in the percentage of MN and fragmented nuclei was observed. In EM-C11 cells the background level of SCEs (0.939±0.182) was approximately 10-fold higher than in CHO-9 (0.129±0.027) and higher levels of multinucleated cells and MN were also found. In EM-C11, even low doses of Me-lex (25µM) led to a significant increase in genomic damage. These results indicate that XRCC1 deficiency can lead to genomic instability even in the absence of an exogenous genotoxic insult and low levels of Me-lex-induced lesions, i.e., 3-mA and/or a BER intermediate, can exacerbate this instability.
登录
查看更多内容
DOI：
10.1016/j.mrfmmm.2009.10.007
发表时间：
2010-01-05
影响因子：
2.3
作者：
Monti, Paola;Traverso, Ilaria;Casolari, Laura;Menichini, Paola;Inga, Alberto;Ottaggio, Laura;Russo, Debora;Iyer, Prema;Gold, Barry;Fronza, Gilberto
通讯作者：
Fronza, Gilberto
影响因子：
4.1
作者：
Encell, L;Shuker, DEG;Gold, B
通讯作者：
Gold, B
影响因子：
4.8
作者：
Kelly, JD;Inga, A;Fronza, G
通讯作者：
Fronza, G
影响因子：
14.9
作者：
Plosky BS;Frank EG;Berry DA;Vennall GP;McDonald JP;Woodgate R
通讯作者：
Woodgate R
影响因子：
4.8
作者：
Beernink, PT;Hwang, M;Thelen, MP
通讯作者：
Thelen, MP