Discovery of Insect and Human Dengue Virus Host Factors

Dengue fever (DF) is the most frequent arthropod-borne viral disease of humans, with almost half of the world's population at risk of infection(1). The high prevalence, lack of an effective vaccine, and absence of specific treatment conspire to make DF a global public health threat(1, 2). Given their compact genomes, dengue viruses (DENV 1-4) and other flaviviruses likely require an extensive number of host factors; however, only a limited number of human, and an even smaller number of insect host factors have been identified(3-10). To discover insect host factors required for DENV-2 propagation, we carried out a genome-wide RNA interference screen in Drosophila melanogaster cells using a well-established 22,632 dsRNA library. This screen identified 116 candidate dengue virus host factors (DVHFs) (Supplementary Fig. 1). While some were previously associated with flaviviruses (e.g., V-ATPases and alpha-glucosidases)(3-5, 7, 9, 10), most DVHFs were newly implicated in DENV propagation. The dipteran DVHFs had eighty-two readily recognizable human homologues and, using a targeted siRNA screen, we showed that forty-two of these are human DVHFs. This indicates remarkable conservation of required factors between dipteran and human hosts. This work suggests novel approaches to control infection in the insect vector and the mammalian host.