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The A1762T/G1764A mutations, one of the most common mutations in the hepatitis B virus basal core promoter, are associated with the progression of chronic HBV infection. However, effects of these mutations on HBV replication remains controversial. This study aimed to systematically investigate the effect of the mutations on HBV replication and its underlying mechanisms. Using the prcccDNA/pCMV‐Cre recombinant plasmid system, a prcccDNA‐A1762T/G1764A mutant plasmid was constructed. Compared with wild‐type HBV, A1762T/G1764A mutant HBV showed enhanced replication ability with higher secreted HBV DNA and RNA levels, while Southern and Northern blot indicated higher intracellular levels of relaxed circular DNA, single‐stranded DNA, and 3.5 kb RNA. Meanwhile, the mutations increased expression of intracellular core protein and decreased the production of HBeAg and HBsAg. In vitro infection based on HepG2‐NTCP cells and mice hydrodynamic injection experiment also proved that these mutations promote HBV replication. 5′‐RACE assays showed that these mutations upregulated transcription of pregenomic RNA (pgRNA) while downregulating that of preC RNA, which was further confirmed by full‐length transcriptome sequencing. Moreover, a proportion of sub‐pgRNAs with the potential to express polymerase were also upregulated by these mutations. The ChIP‐qPCR assay showed that A1762T/G1764A mutations created a functional HNF1α binding site in the BCP region, and its overexpression enhanced the effect of A1762T/G1764A mutations on HBV. Our findings revealed the mechanism and importance of A1762T/G1764A mutations as an indicator for management of CHB patients, and provided HNF1α as a new target for curing HBV‐infected patients. [ABSTRACT FROM AUTHOR]

The article offers information on a research related to over-gap PCR (Polymerase Chain Reaction) amplification to identify presence of replication-competent HBV DNA (hepatitis B virus Deoxyribonucleic Acid) from integrated HBV DNA. It notes the evaluation of discrimination between the ccc (covalently closed circular) DNA, the rc (relaxed circular) DNA and the integrated double strand linear HBV DNA.

Hepatitis B virus (HBV) infection is still a health care crisis in the world, and a considerable number of chronic hepatitis B patients die of end-stage liver diseases, including liver cirrhosis and hepatocellular carcinoma. A previous study has reported that sex-determining region Y box 4 (SOX4) promotes HBV replication by binding to the AACAAAG motif in the viral genome. However, such SOX4 binding site was not found in the genome of the majority of HBV genotype strains. Further, we found that SOX4 inhibited rather than promoted the replication of most HBV strains. In line with this, HBV replication was significantly enhanced when the endogenous SOX4 was knocked down. Moreover, we demonstrated that the SOX4-induced suppression of HBV replication was mainly mediated by hepatocyte nuclear factor 4α (HNF4α). Taken together, our findings suggest that SOX4 plays an important antiviral role by inhibiting HNF4α expression in most HBV strains. • Only a few HBV strains of genotypes A and D contain the SOX4 binding site "AACAAAG". • SOX4 inhibits the replication of most HBV strains. • SOX4 inhibits HBV replication by suppressing HNF4α expression. [ABSTRACT FROM AUTHOR]