Hepatitis B Virus A1762T/G1764A Mutation Has a Minor Effect on the Viral Spliced DNA Expression

: Background: Hepatitis B virus (HBV) is the major cause of chronic hepatitis B, which can lead to liver cirrhosis and hepatocellular carcinoma. During HBV replication, splicing of viral RNA frequently occurs, and the spliced RNA or DNA has been reported to be related to the development of liver disease. HBV transcription is mainly regulated by core promoter ranging from nucleotide 1613 to 1849 and the A1762T/G1764A mutation, which can increase the viral transcription, is frequently detected in this region. Objective: The study aimed to analyze the effect of the A1762T/G1764A mutation in the core promoter of HBV on viral RNA splicing. Methods: The wild type (WT) and the A1762T/G1764A mutant HBV genome were cloned into the pCDNA3.1 vector, which was then transiently transfected into HepG2 cells. The intracellular HBV DNA and core protein were determined by the Southern blot and the Western blot, respectively. The relative level of HBSD was examined by quantitative PCR using TB green reagent. Results: the A1762T/G1764A mutation could enhance the ability of viral replication, however, had a minor effect on HBSD expression. Conclusion: The double mutation in CP could regulate the viral transcription, but was not involved in the viral RNA splicing.