Gammacarmovirus (taxid:1911601)



Non-enveloped, spherical, icosahedral, about 28-34 nm in diameter, capsid with a T=3 icosahedral symmetry. 30 hexameric capsomers per nucleocapsid (virion composed of 180 protein subunits).



Linear, ssRNA(+) genome of 4.2 kb, which lacks a cap structure and a poly(A)tail.


The virion RNA is infectious and serves as both the genome and viral messenger RNA. Two 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. The downstream genes encoding the movement proteins and capsid protein (which acts as a viral suppressor of RNA silencing) are translated from subgenomic RNAs.
Cap-independent translation is mediated possibly through the interaction between a 3'-cap-independent translation element and a 5'UTR stem-loop.




  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 and movement proteins.
  7. Virus assembly in the cytoplasm.
  8. Viral movement protein probably mediates virion cell-to-cell transfer.

Matching UniProtKB/Swiss-Prot entries

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4 entries grouped by protein

1 entry

Capsid protein (Coat protein) (p42)

Melon necrotic spot virus (MNSV) reference strain

1 entry

Double gene block protein 1 (DGBp1) (Movement protein P7A)

Melon necrotic spot virus (MNSV) reference strain

1 entry

Double gene block protein 2 (DGBp2) (Movement protein P7B)

Melon necrotic spot virus (MNSV) reference strain

1 entry

RNA-directed RNA polymerase (EC (p89)

Melon necrotic spot virus (MNSV) reference strain