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线虫DDR食道球特异挽救对辐射诱导胚胎致死的影响及相关机制研究

Studies on Effect and Its Releated Mechanism of Pharynx-specific Rescue of DDR on Radiation-induced Embryonic Lethality in Caenorhabditis Elegans

  • 摘要: DNA损伤反应(DDR)是生命对抗外源和内源性氧化胁迫的主要机制之一。在生命体的不同细胞和组织中DDR具有不同的激活程度,本研究以模式生物秀丽隐杆线虫为实验对象,通过构建DDR通路上游关键基因hus-1的食道球特异表达转基因系,并将其杂交到hus-1突变背景获取DDR食道球特异挽救品系BPL1121、BPL1122和BPL1123,探究DDR异质性激活对辐射生物效应的影响及其内在机制。利用该实验体系检测DDR食道球挽救对γ辐射诱导胚胎致死的影响。与hus-1突变体线虫相比,辐射当代BPL1121线虫的胚胎致死率由24.72±1.77增加到42.66±1.18(P<0.01),这种增强效应延续到了未经过直接辐照的F1子代线虫(P<0.01),但在F2线虫中恢复到本底水平(P>0.05)。线虫中的类胰岛素通路与线虫的生长、发育和繁殖等行为密切相关,daf-2是该信号通路上的一个关键基因。把BPL1121引入到daf-2突变背景,发现DAF-2功能缺失明显抑制了BPL1121线虫的胚胎辐射致死。DDR食道球异质性激活增加了生殖细胞的辐射敏感性,类胰岛素途径参与了食道球DDR对生殖细胞辐射敏感性的远程调控。

     

    Abstract: DNA damage response (DDR) is one of the main mechanisms, by which life counters against exogenous and endogenous oxidative stress induced DNA damage. In an organism, the DDR in different cells and tissues has various levels of activation. . Using the model organism Caenorhabditis elegans as experimental objects, we constructed a transgenic line for the pharynx-specific expression of hus-1 gene, upstream of the DDR pathway, and then introduced into hus-1 mutation background, generating DDR pharynx-specific rescue lines BPL1121, BPL1122 and BPL1123 . The experimental system was used to detect the effect of DDR pharynx rescue on the embryos lethality of γ radiation induced and investigate the effects of heterogeneous activation of DDR on radiation biological effects and its underlying mechanisms. Results showed that the embryonic lethality of irradiated BPL1121 worms increased from 24.72 ± 1.77 to 42.66 ± 1.18 (P < 0.01) compared with hus-1 mutant worms, this enhancement continued up to the intact F1 progeny of non-irradiated worms (P < 0.01), although F2 progeny return to background levels (P > 0.05). The insulin-like pathway in nematodes is closely related to the growth, development and reproduction behaviors of nematodes, and daf-2 is a key gene in this signaling pathway. Introducing BPL1121 into the background of daf-2 mutation, it was found that DAF-2 functional loss significantly inhibited the embryonic radiation lethality of BPL1121 worms. The heterogeneous activation of DDR in pharynx increases the radiation sensitivity of germ cells, and the insulin-like pathway participates in the remote regulation of pharyngeal DDR to radio-sensitivity of germ cells.

     

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