Cheng, Adam2021-10-132021-10-132019-08https://hdl.handle.net/11299/224954University of Minnesota Ph.D. dissertation. August 2019. Major: Microbiology, Immunology and Cancer Biology. Advisor: Reuben Harris. 1 computer file (PDF); xvi, 208 pages.The APOBEC3 family of DNA cytosine deaminases plays an important role in antiviral innate immunity. In this thesis, we describe the novel function of APOBEC3B as a physiologic restriction factor against herpesviruses such as Epstein-Barr virus and herpes simplex virus type 1. We additionally define the counteraction mechanism imparted by herpesviruses using the virus-encoded ribonucleotide reductase large subunit. These viral proteins directly bind A3B to inhibit enzymatic activity, relocalize it away from replicating viral DNA, and protect the virus from A3B-mediated hypermutation for preservation of the viral genome. These results have the potential to reveal new modes of antiviral therapy and have implications in the treatment of A3B-driven cancers.enA3BAPOBECAPOBEC3Host-pathogen interactionsRibonucleotide reductaseRNRThesis or Dissertation