Skip to main content Accessibility help
×
Home
  • Get access
    Check if you have access via personal or institutional login
  • Cited by 1
  • Print publication year: 2004
  • Online publication date: July 2010

4 - RNA-based immunity in insects

    • By Rui Lu, Center for Plant Cell Biology, Department of Plant Pathology, University of California, Riverside, CA 92521, USA, Hongwei Li, Center for Plant Cell Biology, Department of Plant Pathology, University of California, Riverside, CA 92521, USA, Wan-Xiang Li, Center for Plant Cell Biology, Department of Plant Pathology, University of California, Riverside, CA 92521, USA, Shou-Wei Ding, Center for Plant Cell Biology, Department of Plant Pathology, University of California, Riverside, CA 92521, USA
  • Edited by S. H. Gillespie, University College London, G. L. Smith, Imperial College of Science, Technology and Medicine, London, A. Osbourn
  • Publisher: Cambridge University Press
  • DOI: https://doi.org/10.1017/CBO9780511754845.005
  • pp 63-74

Summary

INTRODUCTION

Drosophila has been an excellent model for the mechanistic studies of innate immunity (Hoffmann, 2003). Recently, a new RNA-based antiviral immunity with features of both innate and adaptive immunities has been described in Drosophila and Anopheles cells (Li et al., 2002, 2004). This RNA-silencing-mediated immunity is characterized by the production of pathogen-derived, 22-nt small RNAs that serve as specificity determinants inside a multi-subunit complex. Similar to innate immunity, however, the new invertebrate antiviral response is capable of a rapid virus clearance in the absence of a virus-encoded suppressor of RNA silencing. The discovery of a new antiviral pathway in insects opens up the possibility of using this pathway to prevent transmission of vector-borne virus pathogens such as dengue and West Nile viruses.

THE RNA-SILENCING PATHWAY

Homology-dependent gene silencing was discovered in transgenic plants in a form of co-suppression between introduced transgenes or between a transgene and its homologous endogenous gene (Matzke et al., 1989; Napoli et al., 1990; Van der Krol et al., 1990). Similar gene-silencing phenomena have subsequently been described in a wide range of eukaryotic organisms such as fungi, worms, flies and mammals (Denli & Hannon, 2003; Fire et al., 1998). A generic term, RNA silencing (Ding, 2000), has been used to describe these related RNA-guided gene regulatory mechanisms variously termed post-transcriptional gene silencing (PTGS) in plants, quelling in fungi and RNA interference (RNAi) in animals.

A core feature of RNA silencing detected in all organisms is the production of 21–26-nt small RNAs from structured or double-stranded RNA (dsRNA) by the endoribonuclease Dicer (Bernstein et al., 2001; Hamilton et al., 2002; Hamilton & Baulcombe, 1999; Hammond et al., 2000; Zamore et al., 2000).