Quantification of HBV Covalently Closed Circular DNA from Liver Tissue by Real-Time PCR

Hepadnaviruses utilize an unusual replication strategy. On infection, the partially double-stranded open circular genomic DNA is transported to the hepatocyte nucleus, where host-cell enzymes convert it to a relaxed circular fully double-stranded molecule. From this replicative form is generated a covalently closed circular (ccc) DNA, which associates with cellular histones to form a viral minichromosome (1,2). The HBV (hepatitis B virus) ccc DNA remains in the cell nucleus and serves as the transcriptional template for HBV-RNA production.