Download or read book Antiviral RNAi is Initiated by DsRNA Internalization Into Midgut Cells in the Insect Model Drosophila written by Benjamin Obadia and published by . This book was released on 2013 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Insects have successfully adapted to an incredible variety of environments where they co-exist with diverse microorganisms (e.g., fungi, bacteria, viruses). Consequently, insect defense mechanisms have been shaped over their evolution to generate a versatile immune system, allowing them to better survive infection, but also to better spread infection to others. Although insect-borne diseases have caused severe threats to humans since recorded history, studies had mainly focused on the dissection and understanding of insect-bacterium interactions while insect-virus interactions have remained poorly characterized. A few years ago, the discovery of RNA interference (RNAi) as an antiviral immune mechanism opened new perspectives on understanding insect immunity, which may potentially lead to the control of insect-borne viruses. RNAi is naturally triggered by virus-derived double-stranded (ds) RNA molecules and gives the insect a sequence-specific way of controlling viral replication. In insects, the antiviral RNAi response may also be mounted after artificial immunization with dsRNA, and evidence shows that a systemic protective state is established against viruses. Using the insect model Drosophila melanogaster, the present work inquires on the capacity of dsRNA to generate such a systemic silencing response against RNA viruses and focuses on the fate of dsRNA once in the insect organism. We provide evidence that the intestinal epithelium is the principal tissue involved in dsRNA uptake from both environmental and systemic media. The antiviral immune property of the midgut mediated by RNA interference is also debated.