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Rho即Ras相似物鸟苷三磷酸酶(Ras homologue guanosine triphosphatases,GTPase),是小GTPase家族(small GTPase family)中的一个亚家族。Rho蛋白亚家族在人类中已发现至少有25个成员,RhoA、Rac1和Cdc42是其中被研究得最多的3个小G蛋白[1]。Rho在细胞中参与调控很多生物学过程,包括细胞骨架组装、细胞运动、基因表达、细胞周期、细胞增殖和存活等。在参与细胞生理活动过程中,Rho分子呈现两种相互转换的形式:与鸟苷二磷酸(guanosine diphosphate,GDP)结合的非活化态以及与GTP结合的活化态。上游信号刺激使GDP从非活化态Rho蛋白中解离下来,并使Rho蛋白结合上GTP成为活化态,这一分子过程由鸟嘌呤核苷酸交换因子(guanine nucleotide exchange factors,GEFs)催化完成[2]。多数GEFs都在细胞质中发挥作用,但是RhoA的特异性GEF——神经上皮细胞转化基因1(neuroepithelioma transforming gene 1,Net1)却位于细胞核中[3]。既往研究表明,电离辐射会激活RhoA,从而促进肌动蛋白应力纤维的形成及细胞存活[4]。最新研究发现,正是位于细胞核中的Net1受到电离辐射刺激后激活RhoA[5]。但是关于Net1在电离辐射损伤反应中的生物学功能尚不清楚。因而本研究采用RNA干扰技术特异性沉默Net1,进一步探讨Net1表达对细胞的电离辐射损伤反应的影响。
shRNA干扰沉默Net1基因对电离辐射损伤反应的影响
The effects of short hairpin RNA-mediated silencing Net1 on ionizing radiation-induced damage responses
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摘要:
目的 研究神经上皮细胞转化基因1(NET1)在电离辐射损伤反应中的生物学功能。 方法 运用RNA干扰技术,在细胞中特异性沉默Net1基因,然后通过集落存活实验和免疫印迹法研究抑制Net1表达对细胞的电离辐射损伤反应的影响。 结果 Net1敲低表达的细胞对电离辐射的敏感性增强,表现为更多细胞发生了凋亡,并且在γ射线照射后,毛细血管扩张性共济失调症突变蛋白(ATM)和细胞周期检查点激酶2(Chk2)的磷酸化水平也比对照细胞增强。 结论 Net1对于受到电离辐射的细胞有一定的保护作用,很可能在电离辐射损伤修复中具有重要作用。 -
关键词:
- 电离辐射 /
- RNA干扰 /
- 细胞凋亡 /
- 神经上皮细胞转化基因1
Abstract:Objective To study the biological roles of the neuroepithelioma transforming gene 1 (Net1)in the cellular responses to ionizing radiation(IR)-induced damage. Methods Specific shRNA was used to deplete Net1 in cells. The effects of Net1 depletion on the cellular responses to ionizing radiation were investigated through the colonogenic survival assay and immunoblotting analysis of DNA damage response proteins′ phosphorylation. Results Net1-depleted cells were more sensitive to IR, with a significantly increased induction of apoptosis. In response to IR, the phosphorylation levels of ataxia-telangiectasia mutated and checkpoint kinase 2 were much higher in the Net1-depleted cells than that in the control cells. Conclusion Net1 protects IR-treated cells from apoptosis and possibly plays an important role in IR-induced damage response and repair. -
Key words:
- Ionizing radiation /
- RNA interference /
- Apoptosis /
- Neuroepithelioma transforming gene
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