Super-induction of Dicer-2 expression by alien double-stranded RNAs: an evolutionary ancient response to viral infection?

Jesus Lozano, Eva Gomez-Orte, How-Jing Lee, Xavier Belles

Research output: Contribution to journalArticle (Academic Journal)peer-review

27 Citations (Scopus)

Abstract

Dicer-2 is a ribonuclease involved in the insect RNAi pathway. On attempting to knockdown Dicer-2 expression in the insect Blattella germanica by RNAi, we found that treatment with Dicer-2 dsRNA upregulated the targeted mRNA. This unexpected result was also observed after treating with a nucleopolyhedrovirus dsRNA. Experiments with this alien dsRNA showed an all-or-none response with a threshold for inducing Dicer-2 upregulation between 0.4 and 0.04 μg in terms of dsRNA concentration and between 50 and 20 bp in terms of dsRNA length. The response seems specific of dsRNA given that equivalent experiments carried out with dsDNA did not affect Dicer-2 expression. In insects, Dicer-2 is postulated to be a sensor of viral infections and a key antiviral defense element. The upregulation of Dicer-2 expression after dsRNA administration fits well with this sensor role, and the occurrence of this mechanism in B. germanica, a phylogenetically basal insect, suggests that sensing alien RNAs might be an ancestral function of Dicer-2 proteins.

Original languageEnglish
Pages (from-to)229-35
Number of pages7
JournalDevelopment Genes and Evolution
Volume222
Issue number4
DOIs
Publication statusPublished - Jul 2012

Keywords

  • Animals
  • Biological Evolution
  • Blattellidae
  • DNA, Viral
  • Phylogeny
  • RNA, Double-Stranded
  • Ribonuclease III
  • Up-Regulation

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