Totiviridae (taxid:11006)



Non enveloped, icosahedral virion composed of a single capsid protein (CP), about 40 nm in diameter. The capsid has a T=2* icosahedral symmetry.



Linear dsRNA genome of 4.6-6.7 kb. Contains 2 overlapping ORFs gag and pol, respectively encoding CP and RdRp. Some totiviruses contain a third small 5'-proximal potential ORF.


The dsRNA genome is never completely uncoated, to prevent activation of antiviral state by the cell in response to dsRNA. The viral polymerase synthesizes a mRNA, which is translocated to the cell cytoplasm where it is translated.
Translation is initiated on a unique internal ribosome entry site (IRES) element situated at the 5'-UTR.
In most totiviruses, the plus-strand viral transcript is flanked by a 5'untranslated region (5'-UTR) and a 3'-UTR and directs the translation of a major CP (Gag) and a minor fusion protein CP-RdRP (Gag-Pol) via a -1 ribosomal frameshift.
In other totiviruses (e.g. Hv190SV), RDRP is detected only as a separate, non-fused polypeptide and may be expressed through a termination-reinitiation mechanism.




  1. Virus either remains intracellular (totivirus) or attachement to host receptors mediates endocytosis of virus into host cell (Giardiavirus).
  2. Transcription of the dsRNA genome by viral polymerase occurs inside the virion, so that dsRNA is never exposed to the cytoplasm. This plus-strand transcript is used as template for translation.
  3. (+)RNAs are encapsidated in a sub-viral particle, in which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
  4. Mature virions are transmitted to new cell during cell division, sporogenesis, cell fusion (totivirus) or are released from the host cell (Giardiavirus).

Matching UniProtKB/Swiss-Prot entries

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13 entries grouped by strain

3 entries

Leishmania RNA virus 1 - 1 (isolate Leishmania guyanensis) (LRV-1-1) reference strain

CAPSD_LRVLG Major capsid protein (Major coat protein)
RDRP_LRVLG Probable RNA-directed RNA polymerase (EC
ORF1_LRVLG Putative ORF1 protein

2 entries

Giardia lamblia virus (isolate Wang) (GLV) reference strain

RDRP_GLVWB Probable RNA-directed RNA polymerase (EC (Gag-Pol protein)
CAPSD_GLVWB Major capsid protein (Gag protein) (Major coat protein)

2 entries

Helminthosporium victoriae virus-190S (Hv190SV) reference strain

CAPSD_HV19S Major capsid protein (Major coat protein)
RDRP_HV19S Probable RNA-directed RNA polymerase (EC

2 entries

Saccharomyces cerevisiae virus L-A (ScV-L-A) (ScVL1) reference strain

GAG_SCVLA Major capsid protein (Gag protein) (Major coat protein)
RDRP_SCVLA Probable RNA-directed RNA polymerase (EC (Gag-Pol protein)

2 entries

Saccharomyces cerevisiae virus L-BC (ScV-L-BC) (ScVLa) reference strain

RDRP_SCVLB Probable RNA-directed RNA polymerase (EC (Gag-Pol protein)
GAG_SCVLB Major capsid protein (Gag protein) (Major coat protein)

1 entry

Ustilago maydis P4 virus (UmV4) (UmV-P4)

KP4T_UMV4 KP4 killer toxin (Fungal toxin KP4) (Killer protein 4)

1 entry

Ustilago maydis P6 virus (UmV6) (UmV-P6)

KP6T_UMV6 KP6 killer toxin (Killer protein 6) [Cleaved into: KP6 killer toxin subunit alpha (VP10); KP6 killer ...