›› 2011, Vol. 54 ›› Issue (8): 927-932.doi:

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Advances in the mechanism of antiviral RNA silencing in insects

 WU  Ping, GUO  Xi-Jie, ZHOU  Jia-Chun   

  • Received:2011-03-02 Online:2011-08-20 Published:2011-08-20
  • Contact: GUO Xi-Jie E-mail:guoxijie@126.com
  • About author:wp4114@163.com

Abstract: RNA silencing is identified as a general and evolutionarily conserved antiviral defense mechanism in insects. Meanwhile, viruses adapt the strategy by encoding suppressors of RNA silencing to counter the host-defense. Based on the related achievements in Drosophila, this article reviews the mechanism of antiviral RNA silencing, the characteristics and functions of RNA silencing suppressors, and the coevolution between hosts and viruses. Studies showed that RNA interference mediated by siRNA (small interfering RNAs, siRNA) plays a vital role in antiviral defense in Drosophila. Dicer-2(Dcr-2), argonaute-2 (AGO2) and R2D2 are three key components in siRNA pathway in Drosophila. Flies with these three genes knockdowned were hypersensitive to RNA virus infection. Additionally, several core genes involved in RNA interference were identified, including vasa intronic gene, aubergine, armitage, rm62 and piwi, which also play roles in antiviral defense in Drosophila. Three viral suppressors of RNAi (VSRs) have been identified in Drosophila viruses, i.e., FHV-B2, DCV-1A and CrPV-1A. FHV-B2 and DCV-1A inhibit RNA silencing by binding dsRNA or siRNA while CrPV-1A by targeting AGO2. During the boundless process of evolution, the hosts and viruses counter each other as well as coevolve. Components of antiviral silencing against highly diverse VSRs should be continuously and rapidly evolving.

Key words: Insect, RNA interference, antiviral mechanism, suppressors of RNA silencing, coevolution