Academia Sinica researchers Kevin Tsai and Pei-Yi (Alma) Su found that the RNA of Hepatitis B viruses (HBV) are enriched with small chemical modifications, shedding new light on the molecular mechanisms of HBV replication, one of the leading causes of liver cirrhosis and cancer.
Among the viral RNA modifications found, the cytidine methylation 5-methylcytidine (m5C) was found on viral RNAs at 11x higher amounts than on cellular messenger RNAs. Viral m5C is deposited by the cellular enzyme NSUN2 and removal of NSUN2 resulted in a loss of m5C from viral RNAs and failure in the production of viral structural proteins and genomic DNA.
Thus, Tsai and colleagues uncovered a host-aided RNA modification required for the production of infectious viral particles, suggesting a unique mechanism that may be used as an antiviral target. A collaboration with Chiaho Shih of China Medical University and Miao-Hsia Lin & Pei-Jer Chen of National Taiwan University, this study was published June 3rd, 2024 in the Proceedings of the National Academy of Sciences of the USA.