Identification of cellular functions involved in Hepatitis B Virus infection via a novel RNA sensing and editing dependent reporter system

About This Grant

Abstract Hepatitis B virus (HBV) chronically infects 254 million people worldwide and accounts for 1.1 million deaths per year due to cirrhosis and liver cancer. Finding a cure for this disease is urgently needed, which requires a more thorough understanding of the key molecular events driving establishment and persistence of HBV infections. Thus far, identification of HBV-hepatocyte interactions is mostly achieved through conventional focused screens or one-gene-at-a-time approaches. Due to the overlapping feature of the HBV genome, unbiased genetic screens by reporter HBV viruses allowing phenotypic selection have not been possible. To overcome this challenge, our lab recently developed an RNA sensing and editing based HBV reporter without modifying the viral genome, but instead introduces reporter genes containing stop codon (UAG) that becomes contingently translatable upon precise RNA editing (UIG, translate as UGG) guided by the complementary HBV RNA sequences. Our preliminary data demonstrated that it functions in an HBV RNA-sensing and ADAR RNA-editing dependent manner, and an HBV puromycin reporter allows for HBV infection-dependent survival of cells following puromycin treatment. Therefore, this novel cell culture-based HBV infection reporter system permits unbiased genome- wide screens using sgRNA, cDNA and chemical libraries, etc. The purpose of this R21 grant application entitled “Identification of cellular functions involved in Hepatitis B Virus infection via a novel RNA sensing and editing dependent reporter system” is to further validate the newly developed system and to identify still elusive host factors required for early steps in HBV infection and for amplification of the viral genome. We anticipate that our novel HBV infection reporter assay will allow us to perform the most comprehensive loss-of-function and gain-of-function screens in tissue culture cells to date, and most likely reveal new knowledge on virus-host interactions critical for the HBV life cycle, which will in a short-term enhance our understanding of HBV replication and advance current HBV model systems, and in a long-term, provide potential novel targets for antiviral therapies to combat chronic HBV infections.