Deltavirus

HDV; Satellite virus: infection requires host cell to be co-infected with hepatitis B virus

VIRION

image

Enveloped, spherical about 22 nm in diameter. The virion is covered by helper HBV membrane proteins.

GENOME

image

Circular, ssRNA(-) genome of 1,68 kb. Most of the genome displays complementary strands. Replication occurs by rolling circle, single genome being cleaved/ligated by HDV ribozymes.

GENE EXPRESSION

A single ORF encodes for S-HDAg. Late in infection, genome editing by host ADAR1 extends the S-HDAg ORF by 19 amino acids, inducing production of L-HDAg. Edited genome seems to be unable to replicate.

REPLICATION

NUCLEAR

  1. Virus attaches to host receptors though Major surface antigen.
  2. Fusion of virus membrane with the vesicle membrane; ribonucleocapsid is released in the cytoplasm and migrates to the nucleus.
  3. Transcription of S-HDAg, promoting viral transcription and replication
  4. Symmetrical rolling circle replication by host DNA-dependent RNA polymerase II
  5. later, genomic RNA is edited by host ADAR1, leading to L-HDAg expression which induce packaging of HDV genome at the RE.
  6. Budding by helper HBV proteins.

Host-virus interaction

Inhibition of host Interferon induction

HDV plays a role in inhibition of STAT1 antiviral signaling