A front line defense against microbial invasion is the receptor-mediated recognition of pathogen-associated molecular patterns (PAMPs), which triggers a signaling cascade that results in the induction of initiate innate immune responses, including the secretion of Type-1 interferons. Pathogen-derived nucleic acids, including DNA, function as potent PAMPs that can trigger this response, and are recognized by TLR9, DAI/RNA polymerase Ill, and likely additional DNA-sensing receptors. Murine Gammaherpesvirus 68 (MHV-68) is closely related to human herpesvirus 8 (HHV8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), which is the causative agent of Kaposi's sarcoma. These viruses contain double stranded DNA genomes, and studies indicate that they likely elicit both TLR9-dependent and TLR9- independent antiviral responses. In this study, we propose to leverage systems-level data to elucidate signaling networks and host-pathogen interactions that form the basis of innate immune responses to gammaherpesviruses. To this end, we have used a variety of methods to systematically generate viral host protein-protein interaction maps targeting herpesviruses. We hypothesize that a subset of these interactions underlies viral evasion of innate responses. In this proposal, we will characterize host molecular complex that have been experimentally defined to lie at the interface of HHV8 host-pathogen interactions and innate immune responses. Dr. Chanda has over 10 years experience in functional genomics, innate immune signaling, and genetic analysis in mammalian cells, and Dr. Krogan brings over 10 years of experience in the areas of large-scale proteomic and network analysis. These studies are expected to provide global molecular insight into cellular and viral processes that regulate early immune responses to gammaherpesvirus infection, and will be fundamental towards the development of novel vaccines and adjuvants for HHVB