Fig. 2
From: Hepatitis D: challenges in the estimation of true prevalence and laboratory diagnosis
Schematic representation of HDV life cycle. A HDV virion enters the hepatocyte via HSPGs and NTCP. B The virion loses its envelope and the RNP is imported into the nucleus of the cell. C Within the nucleolus, HDV RNA is replicated using a double rolling circle amplification to form the antigenomic RNA and more genomic RNA. D The mRNA is exported to the cytoplasm where it is translated at the endoplasmic reticulum (ER) to form HDAg. E HDAg return to the nucleus where the S-HDAg isoform promotes further genome replication. S-HDAg and L-HDAg bind to new transcripts of genomic RNA to form new RNPs. F RNPs are exported to the cytoplasm where L-HDAg facilitates association with HBsAg in the ER to assemble new virus particles. G They are then released out of the hepatocyte via the Golgi to infect neighboring cells. HDV hepatitis D virus; L-HDAg large hepatitis D antigen; S-HDAg small hepatitis D antigen; HBsAg hepatitis B surface antigen; RNP ribonucleoprotein; mRNA messenger RNA; NTCP sodium taurocholate cotransporting polypeptide; HSPGs heparan sulphate proteoglycans