Hepadnaviridae

Hepadnaviridae

Characteristics of Virus

• Causes Hepatitis B known as the serum hepatitis
• Partially double stranded DNA
• The partially double-stranded DNA genome, associated with a molecule of P, is found within the core.

Genome Structure

• Orf S = S glycoprotein
• Orf P = Polymerase (RT)
• Orf C= Capsid protein
• Longer version of Capsid protein is HBeAG (secreted protein (E) not present in the virion)
• Orf X = X protein (nonstructural protein with regulatory function)

Replication

• Attachment and fusion at the plasma membrane
• Nucleocapsid released into the cytoplasm
• Nucleocapsid traffics to nucleus
• Genome released into nucleus
• Genome converted (cellular proteins) to covalently closed circular DNA 
• Transcription (cellular RNA polII) of mRNAs and pregenomes (pgRNA) 

Disease

• Causes Hepatitis B
• Transmission via exchange of body fluids
• Also vertical transmission from mothers to infants -
  • HBV much more infectious than HIV
• Acute disease: Liver damage occurs but virus is cleared 
• Chronic disease: Cirrhosis of the liver and primary hepatocellular carcinoma (HCC)
• Can lead to Hepatocelluar Carcinoma