Arenavirus

Molecular biology

VIRION

Enveloped, spherical. Diameter from 60 to 300 nm.

GENOME

Segmented Negative-stranded RNA linear genome, L segment is about 7,5 kb and S segment 3,5 kb.
Encodes for four proteins.

GENE EXPRESSION

Both segments are ambisense. The viral RNA dependent RNA polymerase (L) binds to a promoter on each encapsidated segment, and transcribes a messager RNA. Transcription is terminated by a strong hairpin sequence at the end of each gene. mRNAs are capped, probably by L protein during synthesis.

REPLICATION

CYTOPLASM

  1. Virus attaches to host receptors though GP glycoprotein and is endocytosed into vesicles in the host cell by apoptotic mimicry.
  2. Fusion of virus membrane with the vesicle membrane; ribonucleocapsid is released in the cytoplasm.
  3. Sequential transcription, viral mRNAs are capped in the cytoplasm.
  4. Replication presumably starts when enough nucleoprotein is present to encapsidate neo-synthetized antigenomes and genomes.
  5. The ribonucleocapsid interacts with the Z protein under the plasma membrane and buds, releasing the virion.

Host-virus interaction

Inhibition of host Interferon induction

The Z protein plays a role in inhibition of antiviral signaling through RIG-I