【摘要】 蛋白质多聚ADP核糖化是一种翻译后修饰方式,拟南芥中有3个编码多聚ADP核糖化聚合酶的基因(PARP1,PARP2和PARP3)和两个编码多聚ADP核糖水解酶的基因(PARG1和PARG2),其中PARG1突变体parg1-4对基因毒剂极其敏感,为了了解PARP家族成员PARP2基因与parg1突变体表型的关系,本研究将PARP2突变体parp2-3与parg1-4杂交获得了parp2-3parg1-4双突变体,发现PARP2突变部分恢复了parg1-4对双链断裂基因毒剂zeocin和单链断裂基因毒剂MMS敏感的表型.Western blot结果显示:在zeocin和MMS处理下,parp2-3parg1-4中的PAR信号强度与parg1-4中的相比大大降低.实时荧光定量PCR结果显示:在zeocin和MMS处理下,parg1-4中响应DNA损伤的基因在胁迫初期被显著诱导,胁迫后期与细胞死亡相关的基因表达量明显高于其他基因型植物,但PARP2突变后,parp2-3parg1-4中PAR水平和损伤及死亡基因的表达量均降低,从而部分恢复了parg1-4的敏感表型.更多还原

【Abstract】 Poly(ADP-ribosyl)ation is a posttranslational modification of proteins.Arabidopsis has three poly(ADP ribose)polymerase genes(PARP1,PARP2 and PARP3)and two poly(ADP ribose)glycohydrolase genes(PARG1 and PARG2).Among them,the PARG1 mutant parg1-4 is highly sensitive to genotoxin treatment.To understand the contribution of PARPfamily member activities to the phenotype of the parg1-4 mutant,PARP2 mutant parp2-3 was crossed with parg1-4 to obtain the parp2-3 parg1-4 double mutant.We found that PARP2 mutation partially rescued the sensitive phenotype of parg1-4 to zeocin and MMS treatment.Western blot results showed that PAR level was greatly reduced in parp2-3 parg1-4 compared with parg1-4 under the genotoxin treatment.Quantitative Real-time PCR results showed that under the treatments of zeocin and MMS,DNA damage responsive genes were more activated at the early stages,and the cell death genes had significantly higher expression levels at the later stages in the parg1-4 mutant than in other genotypes.Mutation of PARP2 caused the down-regulation of both PAR level and the expression levels of DNA damage and cell death responsive genes in the parp2-3 parg1-4 mutant,thus partially rescuing the genotoxin-sensitive phenotype of the parg1-4 mutant.更多还原