Nature：RNAi抗病毒免疫研究新进展

　　

生物通报道，美国加州大学微生物与免疫学系，法国巴斯德研究所病毒与RNAi研究中心，巴斯德果蝇遗传与表观遗传学研究所的研究人员在新一期的Nature杂志上发表文章，解析抗病毒反应中RNAi的研究进展。

 

据文章介绍，果蝇与其他昆虫在免疫应答过程中涉及RNAi过程，RNAi作用主要参与局部的抗病毒防卫。先前的研究结论认为，参与RNAi的dsRNA不能在细胞间进行移动，因此研究人员认为果蝇体内没有系统的RNAi作用。

 

然而，加州大学和法国巴斯德研究所的科学家在一项新的试验中推翻了先前的论定。研究人员用辛德毕病毒感染果蝇，观察果蝇免疫应答过程中发生的RNAi现象，结果发现dsRNA能通过病毒免疫信号而传递到不同的细胞中，借此果糖体内RNAi参与的免疫应答形成系统性的免疫应答，而非局部的免疫应答。

 

研究人员认定，无脊椎动物与脊椎动物一样，RNAi参与系统性抗病毒免疫反应，因此说，RNAi现象比原本认定的要保守得多。

 

生物通推荐原文检索：Antiviral immunity in Drosophila requires systemic RNA interference spread

【Abstract】

Multicellular organisms evolved sophisticated defence systems to confer protection against pathogens. An important characteristic of these immune systems is their ability to act both locally at the site of infection and at distal uninfected locations1,. In insects, such as Drosophila melanogaster, RNA interference (RNAi) mediates antiviral immunity. However, the antiviral RNAi defence in flies seems to be a local, cell-autonomous process, as flies are thought to be unable to generate a systemic RNAi response8. Here we show that a recently defined double-stranded RNA (dsRNA) uptake pathway9 is essential for effective antiviral RNAi immunity in adult flies. Mutant flies defective in this dsRNA uptake pathway were hypersensitive to infection with Drosophila C virus and Sindbis virus. Mortality in dsRNA-uptake-defective flies was accompanied by 100-to 105-fold increases in viral titres and higher levels of viral RNA. Furthermore, inoculating naked dsRNA into flies elicited a sequence-specific antiviral immune response that required an intact dsRNA uptake pathway. These findings suggest that spread of dsRNA to uninfected sites is essential for effective antiviral immunity. Notably, infection with green fluorescent protein (GFP)-tagged Sindbis virus suppressed expression of host-encoded GFP at a distal site. Thus, similar to protein-based immunity in vertebrates, the antiviral RNAi response in flies also relies on the systemic spread of a virus-specific immunity signal.