RNA interference acts as a natural antiviral response to O'nyong-nyong virus (Alphavirus; Togaviridae) infection of Anopheles gambiae. Export

@article{citeulike:2838329, abstract = {RNA interference (RNAi) is triggered in eukaryotic organisms by double-stranded RNA (dsRNA), and it destroys any mRNA that has sequence identity with the dsRNA trigger. The RNAi pathway in Anopheles gambiae can be silenced by transfecting cells with dsRNA derived from exon sequence of the A. gambiae Argonaute2 (AgAgo2) gene. We hypothesized that RNAi may also act as an antagonist to alphavirus replication in A. gambiae because RNA viruses form dsRNA during replication. Silencing AgAgo2 expression would make A. gambiae mosquitoes more permissive to virus infection. To determine whether RNAi conditions the vector competence of A. gambiae for O'nyong-nyong virus (ONNV), we engineered a genetically modified ONNV that expresses enhanced GFP (eGFP) as a marker. After intrathoracic injection, ONNV-eGFP slowly spread to other A. gambiae tissues over a 9-day incubation period. Mosquitoes were then coinjected with virus and either control beta-galactosidase dsRNA (dsbetagal; note that "ds" is used as a prefix to indicate the dsRNA derived from a given gene throughout) or ONNV dsnsP3. Treatment with dsnsP3 inhibited virus spread significantly, as determined by eGFP expression patterns. ONNV-eGFP titers from mosquitoes coinjected with dsnsP3 were significantly lower at 3 and 6 days after injection than in mosquitoes coinjected with dsbetagal. Mosquitoes were then coinjected with ONNV-eGFP and dsAgAgo2. Mosquitoes coinjected with virus and AgAgo2 dsRNA displayed widespread eGFP expression and virus titers 16-fold higher than dsbetagal controls after 3 or 6 days after injection. These observations provide direct evidence that RNAi is an antagonist of ONNV replication in A. gambiae, and they suggest that the innate immune response conditions vector competence.}, address = {Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.}, author = {Keene, K. M. and Foy, B. D. and Sanchez-Vargas, I. and Beaty, B. J. and Blair, C. D. and Olson, K. E.}, citeulike-article-id = {2838329}, citeulike-linkout-0 = {http://dx.doi.org/10.1073/pnas.0406983101}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/15583140}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=15583140}, day = {7}, doi = {10.1073/pnas.0406983101}, issn = {0027-8424}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, keywords = {anopheles, antiviral, arbovirus, innate\_immunity, onyong-nyong, rnai}, month = {December}, number = {49}, pages = {17240--17245}, posted-at = {2009-04-17 19:23:16}, priority = {2}, title = {RNA interference acts as a natural antiviral response to O'nyong-nyong virus (Alphavirus; Togaviridae) infection of Anopheles gambiae.}, url = {http://dx.doi.org/10.1073/pnas.0406983101}, volume = {101}, year = {2004} }

TY - JOUR ID - citeulike:2838329 L3 - citeulike-article-id:2838329 N2 - RNA interference (RNAi) is triggered in eukaryotic organisms by double-stranded RNA (dsRNA), and it destroys any mRNA that has sequence identity with the dsRNA trigger. The RNAi pathway in Anopheles gambiae can be silenced by transfecting cells with dsRNA derived from exon sequence of the A. gambiae Argonaute2 (AgAgo2) gene. We hypothesized that RNAi may also act as an antagonist to alphavirus replication in A. gambiae because RNA viruses form dsRNA during replication. Silencing AgAgo2 expression would make A. gambiae mosquitoes more permissive to virus infection. To determine whether RNAi conditions the vector competence of A. gambiae for O'nyong-nyong virus (ONNV), we engineered a genetically modified ONNV that expresses enhanced GFP (eGFP) as a marker. After intrathoracic injection, ONNV-eGFP slowly spread to other A. gambiae tissues over a 9-day incubation period. Mosquitoes were then coinjected with virus and either control beta-galactosidase dsRNA (dsbetagal; note that "ds" is used as a prefix to indicate the dsRNA derived from a given gene throughout) or ONNV dsnsP3. Treatment with dsnsP3 inhibited virus spread significantly, as determined by eGFP expression patterns. ONNV-eGFP titers from mosquitoes coinjected with dsnsP3 were significantly lower at 3 and 6 days after injection than in mosquitoes coinjected with dsbetagal. Mosquitoes were then coinjected with ONNV-eGFP and dsAgAgo2. Mosquitoes coinjected with virus and AgAgo2 dsRNA displayed widespread eGFP expression and virus titers 16-fold higher than dsbetagal controls after 3 or 6 days after injection. These observations provide direct evidence that RNAi is an antagonist of ONNV replication in A. gambiae, and they suggest that the innate immune response conditions vector competence. IS - 49 JF - Proceedings of the National Academy of Sciences of the United States of America SN - 0027-8424 AD - Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA. EP - 17245 TI - RNA interference acts as a natural antiviral response to O'nyong-nyong virus (Alphavirus; Togaviridae) infection of Anopheles gambiae. VL - 101 SP - 17240 KW - anopheles KW - antiviral KW - arbovirus KW - innate_immunity KW - onyong-nyong KW - rnai AU - Keene, KM AU - Foy, BD AU - Sanchez-Vargas, I AU - Beaty, BJ AU - Blair, CD AU - Olson, KE PY - 2004/12/07/ UR - http://dx.doi.org/10.1073/pnas.0406983101 ER -