Development Genes and Evolution

, Volume 218, Issue 9, pp 505–510

Larval RNAi in Drosophila?

  • Sherry C. Miller
  • Susan J. Brown
  • Yoshinori Tomoyasu
Short Communication

DOI: 10.1007/s00427-008-0238-8

Cite this article as:
Miller, S.C., Brown, S.J. & Tomoyasu, Y. Dev Genes Evol (2008) 218: 505. doi:10.1007/s00427-008-0238-8

Abstract

RNA interference (RNAi) has become a common method of gene knockdown in many model systems. To trigger an RNAi response, double-stranded RNA (dsRNA) must enter the cell. In some organisms such as Caenorhabditis elegans, cells can take up dsRNA from the extracellular environment via a cellular uptake mechanism termed systemic RNAi. However, in the fruit fly Drosophila melanogaster, it is widely believed that cells are unable to take up dsRNA, although there is little published data to support this claim. In this study, we set out to determine whether this perception has a factual basis. We took advantage of traditional Gal4/upstream activation sequence (UAS) transgenic flies as well as the mosaic analysis with a repressible cell marker (MARCM) system to show that extracellular injection of dsRNA into Drosophila larvae cannot trigger RNAi in most Drosophila tissues (with the exception of hemocytes). Our results show that this is not due to a lack of RNAi machinery in these tissues as overexpression of dsRNA inside the cells using hairpin RNAs efficiently induces an RNAi response in the same tissues. These results suggest that, while most Drosophila tissues indeed lack the ability to uptake dsRNA from the surrounding environment, hemocytes can initiate RNAi in response to extracellular dsRNA. We also examined another insect, the red flour beetle Tribolium castaneum, which has been shown to exhibit a robust systemic RNAi response. We show that virtually all Tribolium tissues can respond to extracellular dsRNA, which is strikingly different from the situation in Drosophila. Our data provide specific information about the tissues amenable to RNAi in two different insects, which may help us understand the molecular basis of systemic RNAi.

Keywords

RNAiSystemicTribolium castaneum (red flour beetle)Drosophila melanogaster (fruit fly)Injection

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Sherry C. Miller
    • 1
    • 2
  • Susan J. Brown
    • 1
    • 2
  • Yoshinori Tomoyasu
    • 1
    • 2
  1. 1.Division of BiologyKansas State UniversityManhattanUSA
  2. 2.K-State Arthropod Genomics CenterKansas State UniversityManhattanUSA
  3. 3.The Department of ZoologyMiami UniversityOxfordUSA