Exploring the Genetic Basis of Dengue Virus Transmission
William Shen
Burnaby North Secondary
Floor Location : S 002 H

Infecting an estimated 390 million people per year, Dengue fever viruses (DENv) are the most prevalent vector-borne viruses in the world, yet remain untreatable. Aedes aegypti mosquitoes are the principal vectors of Dengue, although some populations or subsets of populations of Aedes aegypti show a “refractory” phenotype and are incapable of transmitting DENv. Coatsworth et al. of the Lowenberger Lab at Simon Fraser University analyzed differential gene expression between Dengue-susceptible and Dengue-refractory strains of Aedes aegypti, originally field-collected near Cali, Colombia. Among the genes upregulated by susceptible strains is immune enzyme CLIPB34. Although the specific role of CLIPB34 is unknown, I hypothesize that it contributes to the ability of Aedes aegypti to transmit DENv and, therefore, may be useful in genetically engineering DENv-resistant mosquitoes and may constitute a promising gene pathway for the specific targeting of Dengue fever. The overall design of this project involves three major stages: the generation of double-stranded RNA (dsRNA) transcripts of CLIPB34, the assessment of a CLIPB34 RNAi knockdown in Aedes aegypti via dsRNA injection, and the assessment of the impact of this knockdown on DENv transmission. The presence of DENv in the head and abdomen of infected, CLIPB34-knockdown mosquitoes will be evaluated using antibody-mediated immunofluorescence. Thus far, I have verified the integrity of my dsRNA, but have detected up to a 3-fold increase in CLIP gene expression across 60 biological replicates at 72 and 96 hours after injection, compared to water-injected control mosquitoes. These data fundamentally challenge the well established RNA interference model and corroborate other studies that have suggested alternative pathways by which dsRNA can impact gene expression. This obstacle must be overcome before I move on to the final stage of my project.