Blunervirus

VIRION

No data available (08/2017)

GENOME

Segmented, quadripartite, linear, ssRNA(+) genome. The four segments are about 5.9, 3.9, 2.6 and 1.7 kb in size. The genomic RNA is capped, but not polyadenylated.

GENE EXPRESSION

Genomic RNAs serve as messenger RNAs. RNA1 contains 1 ORF encoding the methyltransferase, protease, and helicase domains. RNA2 encodes a second helicase domain and an RNA-dependent RNA polymerase (RdRp) domain. RNA3 encodes five ORFs (p7, p9, p22, p28 and p31), and RNA4 seems to encode a movement protein.

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 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. Each segment is encapsidated.
  7. Viral movement protein probably mediates virion cell-to-cell transfer.