CAREER: Genetic Determinants of Giant Virus Host Range

All living creatures must defend themselves from viral infection to survive. Single-cell eukaryotes, e.g., amoeba, are infected by the largest known viruses (“giant viruses”), but the viral and host genes that control whether a host is susceptible or resistant to infection with these giant viruses are entirely unknown. This project will investigate the viral and host mechanisms that control the susceptibility of amoeba to virus infection. Understanding what genes make an organism resistant to viral infection and how viruses navigate these hurdles may result in new biotechnologies, medical interventions, and basic knowledge. The education plan includes a course-based research experience where undergraduate participants isolate and identify novel giant viruses and describe whether lab-adapted and environmental Acanthamoeba strains are resistant or susceptible to virus infection. This course will give students experience in several aspects of environmental sampling, molecular biology, and virus infection, strengthening the workforce in biotechnology. This project advances NSF’s priorities in Biotechnology. The goal of this research is to identify key determinants of host range in a family of giant viruses, Marseilleviridae, on their host, Acanthamoeba. Acanthamoeba is a commonly used model system for the isolation, propagation, and study of giant virus infection of microbial eukaryotes. The infection of distinct strains of Acanthamoeba with known and novel Marseilleviruses have identified both Acanthamoeba hosts that are broadly resistant to Marseillevirus infection, and individual Marseillevirus strains that can overcome this resistance. This suggests a complex set of interactions that control Marseillevirus host range and provide a robust model system with which to define these unknown variables. This proposal will employ a range of virological techniques to understand what step of the virus lifecycle is impaired in these resistant hosts. Forward genetic screens combining chemical mutagenesis and next-generation sequencing will identify viral genes that are important for overcoming restriction. Candidate viral genes will be systematically mutagenized to identify genes critical to expanding host range and validated through overexpression to show they can expand the host range of highly restricted Marseilleviruses. Finally, genetic screens in Acanthamoeba will also be conducted to identify the host genes capable of restricting Marseillevirus infection. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2540645 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT,01003031DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Tristan Jordan | Institution: University of Washington, SEATTLE, WA | Award Amount: $1,280,000 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2540645 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2540645.html