Goravirus

VIRION

Non-enveloped, rigid helical rods with a helical symmetry, about 20 nm in diameter with a central “canal”. There are two segments.

GENOME

Segmented, linear, ssRNA(+) genome, segments of about 4kb and 6kb. Genomic RNA displays a tRNA-like structure in 3', but no poly-A tail.

GENE EXPRESSION

The virion RNA is infectious and serves as both the genome and viral messenger RNA. The RNA-1 5'-proximal ORFs are directly translated to produce the viral constituents of the replicase complex. RdRp is translated through suppression of termination at the end of ORF1. RNA-2 encodes the capsid protein, triple gene block proteins acting as movement proteins and a viral suppressor of RNA silencing (VSR).

REPLICATION

CYTOPLASMIC

  1. Virus penetrates into the host cell.
  2. Uncoating, and release of the viral genomic RNA into the cytoplasm.
  3. The viral RNA is translated to produce the two proteins necessary for RNA synthesis (replication and transcription).
  4. Replication takes place in cytoplasmic viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).
  5. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  6. The RdRp recognizes internal subgenomic promoters on the negative-sense RNA to transcribe the 3’co-terminal subgenomic RNAs that will generate the capsid protein, movement protein(s) and viral suppressor of RNA silencing (VSR).
  7. Virus assembly in the cytoplasm. Each segment is encapsidated.
  8. Viral movement protein(s) probably mediate virion cell-to-cell transfer.