Functional Analysis of SARS-CoV-2 Proteins in Drosophila Identifies Orf6-induced Pathogenicity Attenuated by Selinexor

Abstract Background: SARS-CoV-2 causes COVID-19 with a widely diverse disease profile that affect many different tissues. The mechanisms underlying its pathogenicity in host organisms remain unclear. Animal models for study the pathogenicity of SARS-CoV-2 proteins are lacking. Methods: Using bioinformatic analysis, we showed that the majority of the virus-host interacting proteins are conserved in Drosophila. Therefore, we generated a series of transgenic lines for individual SARS-CoV-2 genes and used the Gal4-UAS system to express them in various tissues to study their pathogenicity. Results: We found that the Nsp6, Orf6 and Orf7a transgenic flies displayed reduced trachea branching and muscle deficits resulting in “held-up” wing phenotype and poor climbing ability. Furthermore, muscle tissue in these flies showed dramatically reduced mitochondria. Since Orf6 was found to bind nucleopore proteins XPO1, we tested Selinexor, a drug that inhibits XPO1, and found that it could attenuated the Orf6-induced lethality and tissue-specific phenotypes in flies. Conclusions: Our studies here established new Drosophila models for studying the function of SARS-CoV2 genes, identified Orf6 as a highly pathogenic protein in various tissues, and demonstrated the effects of Selinexor for inhibiting Orf6 toxicity with an in vivo model system.