Subfamily: Agantavirinae

Genus: Agnathovirus

Distinguishing features

Wēnlǐng hagfish virus (WEHV) is the only classified agnathovirus. WEHV infects myxinid fish (Shi et al., 2018).

Virion

Virions are unknown.

Nucleic acid

Agnathoviruses have tri-segmented negative-sense RNA genomes of about 14.6 kb (small [S] segment: 3.0 kb; medium [M] segment: 4.8 kb; large [L] segment: 6.8 kb) (Shi et al., 2018).

Proteins

Based on sequence data only, agnathoviruses likely express three structural proteins: nucleoprotein (N), glycoprotein precursor (GPC), and large protein (L) (Shi et al., 2018).

Genome organization and replication

The S segment encodes N, the M segment encodes GPC, and the L segment encodes L (Figure 1 Agnathovirus). Agnathovirus genomic segments are expected to assume circular forms via non-covalent binding of complementary and conserved 3′- and 5′-terminal sequences.

Figure 1 Agnathovirus. Schematic representation of agnathovirus genome organization. The 5′- and 3′-ends of each segment (S, M and L) are, by analogy to other hantavirids, predicted to be complementary at their termini, likely promoting the formation of circular ribonucleoprotein complexes within the virion.

Biology

WEHV infects inshore hagfish (myxinid Eptatretus burgeri (Girard, 1855)) in China (Shi et al., 2018). Replication-competent agnathovirus isolates have not yet been obtained, and hence agnathovirus biology remains to be elucidated.

Species demarcation criteria

The genus currently only includes a single species.