SUMMARY The ongoing SARS-CoV-2 pandemic has brought into stark relief the need for novel therapeutics that can work against a broad spectrum of coronaviruses. Identifying essential host genes involved in both virus replication and antiviral defense could reveal key host-directed viral therapies that have the potential to work against SARS-CoV-2 and future coronavirus outbreaks. The overarching goal of our laboratory is to identify mechanisms of host defense against viral infections. This application aims to identify both host-encoded mechanisms of resistance to infection by SARS-CoV-2 as well as cellular factors critical for virus replication. Based on emerging data and our preliminary studies, our central hypothesis is that the up-regulation of host ‘restriction factors’ that prevent viral entry, constrain virus replication in host cells, or increase the ability of cells to withstand viral-induced cytopathy represent an important strategy in host defense. Our rationale for the proposed work is that identification of such factors will provide new targets for therapeutic intervention, and that these may be less susceptible to resistance than viral-encoded targets. We will use a novel forward-genetic approach to screen for host genes that confer resistance to SARS-CoV-2 infection in BSL3 using the native virus. This will allow us to identify key targets at all stages of virus infection. We will then validate new host targets and use these insights to rationally develop antiviral therapeutic strategies. Our screening approach is innovative because it allows identification of both host genes that confer resistance as well as host genes required for infection, which are normally detected in conventional RNAi-based screens. This work has the potential to identify new targets, including non-coding RNA elements, which would be missed using existing approaches.