Rhabdoviridae

VIRION

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Enveloped, bullet shaped. 180 nm long and 75 nm wide. Certain plant rhabdoviruses are bacilliform in shape and almost twice the length.

GENOME

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Negative-stranded RNA linear genome, about 11-15 kb in size. Varicosavirus genomes consists in two segments. Encodes for 5 to six proteins.

GENE EXPRESSION

The viral RNA dependent RNA polymerase binds the encapsidated genome at the leader region, then sequentially transcribes each genes by recognizing start and stop signals flanking viral genes. mRNAs are capped and polyadenylated by the L protein during synthesis.

REPLICATION

CYTOPLASMIC

  1. Attachement of the viral G glycoproteins to host receptors mediates Clathrin-mediated endocytosis of the virus into the host cell.
  2. Fusion of virus membrane with the vesicle membrane; ribonucleocapsid is released into the cytoplasm.
  3. Sequential transcription , viral mRNAs are capped and polyadenylated by polymerase stuttering in the cytoplasm.
  4. Replication presumably starts when enough nucleoprotein is present to encapsidate neo-synthetized antigenomes and genomes.
  5. The ribonucleocapsid binds to the matrix protein and buds via the host ESCRT complexes occurs at the plasma membrane, releasing new virions.

Host-virus interaction

Host gene expression shutoff

Vesicular stomatitis virus matrix protein blocks nuclear pores, resulting in host mRNA nuclear export inhibiton This shutoff of host gene expression prevents effective antiviral response by the infected cell.

Inhibition of host Interferon induction

Rabies nucleoprotein plays a role in inhibition of RIG-I antiviral signaling
Rabies phosphoprotein may inhibit IRF-3 phosphorylation

Inhibition of host type I interferon signaling

Rabies phosphoprotein may inhibit STAT-I antiviral pathway signaling by preventing nuclear localization of STAT dimers upon activation.