Hepatitis B is one of a few known non-retroviralviruses which employ reverse transcriptionas a part of its replication process. （HIV， a completely unrelated virus， also uses reverse transcription， but it is a retrovirus.） HBV invades the cell by binding to surface receptor and become internalized. The viral core particles then migrate to the hepatocyte nucleus and the partially double-stranded， relaxed circular genomes （RC-DNA） are repaired to form a covalently closed circular DNA （cccDNA）， which is the template for viral genomic and sub-genomic RNAs by cellular RNA polymerase II. Of these， the pregenomic RNA （pgRNA is selectively packaged into progeny capsids and is then reverse-transcribed into new RC-DNA. The core can either bud into the endoplasmic reticulum to be enveloped or exported from the cell or recycled back into the genome for conversion to cccDNA.
