A nucleosome switch primes Hepatitis B Virus infection [RNA-Seq]

Chronic hepatitis B virus (HBV) infection is an incurable global health threat capable of causing liver disease and hepatocellular carcinoma. During the genesis of infection, HBV establishes an independent chromosome, cccDNA, consisting of the circular viral genome and host histones. The first viral protein expressed, HBx, induces degradation of a host silencing factor to facilitate infection. However, the relationship between cccDNA’s chromatin and early HBx transcription state remains poorly understood. Using reconstituted viral chromosomes, we found that nucleosomes in cccDNA drive HBx transcription. We corroborated these findings in cells and further showed that chromatin destabilizing drugs inhibit viral transcription and antigen expression in hepatocytes. Our results shed new light on a long-standing paradox and represent a novel therapeutic avenue for the treatment of chronic HBV. We performed RNA-seq and MNase-seq on HEK293T cells that were transfected with hepatitis B virus (HBV) cccDNA over different timepoitns post transfection. We also performed MNase-seq on HBV cccDNA that was reconstituted with nucleosomes at different levels of saturation.