果蝇Rad50的破坏会导致蛹期致死、DNA双链断裂的积累以及三龄幼虫中细胞凋亡的诱导。

Disruption of Drosophila Rad50 causes pupal lethality, the accumulation of DNA double-strand breaks and the induction of apoptosis in third instar larvae.

作者信息

Gorski Marcin M, Romeijn Ron J, Eeken Jan C J, de Jong Anja W M, van Veen Bert L, Szuhai Karoly, Mullenders Leon H, Ferro Wouter, Pastink Albert

机构信息

Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands.

出版信息

DNA Repair (Amst). 2004 Jun 3;3(6):603-15. doi: 10.1016/j.dnarep.2004.02.001.

DOI:10.1016/j.dnarep.2004.02.001

PMID:15135728

Abstract

The Rad50/Mre11/Nbs1 protein complex has a crucial role in DNA metabolism, in particular in double-strand break (DSB) repair through homologous recombination (HR). To elucidate the role of the Rad50 protein complex in DSB repair in a multicellular eukaryote, we generated a Rad50 deficient Drosophila strain by P-element mediated mutagenesis. Disruption of Rad50 causes retarded development and pupal lethality. To investigate the mechanism of pupal death, brains and wing imaginal discs from third instar larvae were studied in more detail. Wing imaginal discs from Rad50 mutant larvae displayed a 3.5-fold increase in the induction of spontaneous apoptotic cells in comparison to their heterozygous siblings. This finding correlates with increased levels of phosphorylated histone H2Av, indicating an accumulation of DSBs in Rad50 mutant larvae. A 45-fold increase in the frequency of anaphase bridges was detected in the brains of Rad50 deficient larvae, consistent with a role for Rad50 in telomere maintenance and/or replication of DNA. The induction of DSBs and defects in chromosome segregation are in agreement with a role of Drosophila Rad50 in repairing the DSBs that arise during replication.

摘要

Rad50/Mre11/Nbs1蛋白复合体在DNA代谢中起着关键作用，特别是在通过同源重组（HR）进行双链断裂（DSB）修复方面。为了阐明Rad50蛋白复合体在多细胞真核生物DSB修复中的作用，我们通过P元件介导的诱变产生了一种Rad50缺陷的果蝇品系。Rad50的破坏导致发育迟缓及蛹期致死。为了研究蛹期死亡的机制，我们对三龄幼虫的大脑和翅成虫盘进行了更详细的研究。与杂合子同胞相比，Rad50突变幼虫的翅成虫盘自发凋亡细胞的诱导增加了3.5倍。这一发现与磷酸化组蛋白H2Av水平的增加相关，表明Rad50突变幼虫中存在DSB积累。在Rad50缺陷幼虫的大脑中检测到后期桥频率增加了45倍，这与Rad50在端粒维持和/或DNA复制中的作用一致。DSB的诱导和染色体分离缺陷与果蝇Rad50在修复复制过程中出现的DSB中的作用一致。