Trucco C, Oliver F J, de Murcia G, Ménissier-de Murcia J
UPR 9003 du Centre National de la Recherche Scientifique, Laboratoire Conventionné avec le Commissariat à l'Energie Atomique, Ecole Supérieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, F-67400 Illkirch-Graffenstad, France.
Nucleic Acids Res. 1998 Jun 1;26(11):2644-9. doi: 10.1093/nar/26.11.2644.
To investigate the physiological function of poly(ADP-ribose) polymerase (PARP), we used a gene targeting strategy to generate mice lacking a functional PARP gene. These PARP -/- mice were exquisitely sensitive to the monofunctional-alkylating agent N -methyl- N -nitrosourea (MNU) and gamma-irradiation. In this report, we have analysed the cause of this increased lethality using primary and/or spontaneously immortalized mouse embryonic fibroblasts (MEFs) derived from PARP -/- mice. We found that the lack of PARP renders cells significantly more sensitive to methylmethanesulfonate (MMS), causing cell growth retardation, G2/M accumulation and chromosome instability. An important delay in DNA strand-break resealing was observed following treatment with MMS. This severe DNA repair defect appears to be the primary cause for the observed cytoxicity of monofunctional-alkylating agents, leading to cell death occurring after G2/M arrest. Cell viability following MMS treatment could be fully restored after transient expression of the PARP gene. Altogether, these results unequivocally demonstrate that PARP is required for efficient base excision repair in vivo and strengthens the role of PARP as a survival factor following genotoxic stress.
为了研究聚（ADP - 核糖）聚合酶（PARP）的生理功能，我们采用基因靶向策略来培育缺乏功能性PARP基因的小鼠。这些PARP -/-小鼠对单功能烷化剂N - 甲基 - N - 亚硝基脲（MNU）和γ射线极其敏感。在本报告中，我们使用源自PARP -/-小鼠的原代和/或自发永生化小鼠胚胎成纤维细胞（MEF）分析了这种致死率增加的原因。我们发现PARP的缺失使细胞对甲基磺酸甲酯（MMS）的敏感性显著增加，导致细胞生长迟缓、G2/M期积累和染色体不稳定。在用MMS处理后，观察到DNA链断裂重新封闭出现重要延迟。这种严重的DNA修复缺陷似乎是观察到的单功能烷化剂细胞毒性的主要原因，导致细胞在G2/M期阻滞之后发生死亡。在短暂表达PARP基因后，MMS处理后的细胞活力可以完全恢复。总之，这些结果明确表明PARP是体内有效碱基切除修复所必需的，并强化了PARP作为遗传毒性应激后生存因子的作用。
