The evolution of RNAi as a defence against viruses and transposable elements

Darren J. Obbard, Karl H. J. Gordon, Amy H. Buck, Francis M. Jiggins

Research output: Contribution to journalLiterature reviewpeer-review

Abstract

RNA interference (RNAi) is an important defence against viruses and transposable elements (TEs). RNAi not only protects against viruses by degrading viral RNA, but hosts and viruses can also use RNAi to manipulate each other's gene expression, and hosts can encode microRNAs that target viral sequences. In response, viruses have evolved a myriad of adaptations to suppress and evade RNAi. RNAi can also protect cells against TEs, both by degrading TE transcripts and by preventing TE expression through heterochromatin formation. The aim of our review is to summarize and evaluate the current data on the evolution of these RNAi defence mechanisms. To this end, we also extend a previous analysis of the evolution of genes of the RNAi pathways. Strikingly, we find that antiviral RNAi genes, anti-TE RNAi genes and viral suppressors of RNAi all evolve rapidly, suggestive of an evolutionary arms race between hosts and parasites. Over longer time scales, key RNAi genes are repeatedly duplicated or lost across the metazoan phylogeny, with important implications for RNAi as an immune defence.

Original languageEnglish
Pages (from-to)99-115
Number of pages17
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Volume364
Issue number1513
DOIs
Publication statusPublished - 12 Jan 2009

Keywords

  • antiviral RNAi
  • viral suppressors of RNAi
  • host-parasite coevolution
  • miRNA
  • piRNA
  • transposable element
  • SMALL INTERFERING RNA
  • CAENORHABDITIS-ELEGANS GERMLINE
  • ADAPTIVE PROTEIN EVOLUTION
  • VEIN-YELLOWING-IPOMOVIRUS
  • SELFISH GENETIC ELEMENTS
  • INNATE IMMUNE-RESPONSES
  • SMALL SILENCING RNAS
  • DICER-LIKE PROTEINS
  • C-ELEGANS
  • DROSOPHILA-MELANOGASTER

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