HEPATITIS B PREGENOMICS RNA SPLICING AND ITS ROLE IN VIRAL PERSISTANCE

Abstract

Hepatitis B hijacks the human splicing mechanisms to generate the HBV splice variants. The work in this thesis focused on finding the biological roles of HBV RNA splicing. We found that HBV splice variants were common and abundant in chronic infection, and that the levels rise during the immune clearance phase and peaked just before HBeAg seroconversion. This can be linked to the inhibition of the HBV polymerase function, possibly mediated through the interferons. Our co-transfection experiments showed that the single-spliced defective HBV genome enhanced replication of wild-type HBV DNA. The expression plasmid transfection experiments showed that core protein is the rate-limiting factor of the viral replication, and that spliced RNA may serve as dedicated core mRNA to support viral replication. Small interfering RNA targeting the splice donor and acceptor sites, and the PRE region were found to be effective in suppressing the viral expression and replication.