【摘要】 为探究果蝇肿瘤坏死因子受体相关因子2（drosophila tumor necrosis factor receptor-associated factor 2,dTraf2）对免疫缺陷（immune deficiency, Imd）信号通路的调控作用,构建dTraf2和dTraf2^ΔRING表达载体以及转基因果蝇。利用双荧光素酶报告基因系统、RT-PCR及黏质沙雷菌（Serratia marcescens,SM）感染果蝇的方法,检测dTraf2对Imd信号通路下游抗菌肽表达、果蝇感染病原菌后存活率以及体内病原菌增殖情况的影响。结果显示,过表达dTraf2可显著促进Imd信号下游抗菌肽的表达;dTraf2正调控Imd信号依赖于其泛素连接酶活性;过表达缺失环指（RING finger, RING）结构域的dTraf2对果蝇Imd信号通路下游抗菌肽的表达无明显影响。过表达dTraf2果蝇感染革兰阴性病原菌后抗菌肽表达水平升高,且其存活率亦升高,并抑制了体内病原菌的增殖;在免疫组织里敲低dTraf2可明显抑制Imd信号依赖的果蝇固有免疫反应。该研究提示,dTraf2依赖其RING结构域正向调控果蝇Imd固有免疫反应。更多还原

【Abstract】 To explore how drosophila tumor necrosis factor receptor-associated factor 2（dTraf2） regulates the immune deficiency（Imd） signaling pathway, dTraf2 and dTraf2^ΔRING expression plasmids and transgenic flies were constructed. By utilizing a dual-luciferase reporter system, RT-PCR, and Serratia marcescens（SM） infection assays, we detected the expressional levels of Imd downstream anti-microbial peptides, survival rates, and bacterial titers in infected drosophila. The results showed that over-expression of dTraf2 significantly elevated the expressional levels of anti-microbial peptides. dTraf2 played a positive role in controlling Imd signaling via its ubiquitin ligase activity, since over-expression of RING finger（RING） domain deleted form of dTraf2 almost hardly altered the expression patterns of these anti-microbial peptides. Over-expression of dTraf2 resulted in increased anti-microbial peptide induction and host survival rate, and antagonized bacterial proliferation post pathogenic infection. Knocking down of dTraf2 in immune tissues greatly prevented the Imd-dependent innate immune response in drosophila. Taken together, our studies suggest that dTraf2 positively regulates drosophila Imd innate immune response via its RING domain.更多还原