Family: Nairoviridae

Genus: Shaspivirus

Distinguishing features

Shāyáng spider virus 1 (SySV1) is the only classified shaspivirus. SySV1infects araneid spiders (Li et al., 2015).

Virion

Virions are unknown.

Nucleic acid

Shaspiviruses have trisegmented negative-sense RNA genomes of 20.2 kb (small [S] segment: 1.9 kb; medium [M] segment: 4.8 kb; large [L] segment: 13.5 kb) (Li et al., 2015). Shaspivirus genomic segments are expected to assume circular forms via non-covalent binding of complementary and conserved 3′- and 5′-terminal sequences.

Proteins

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

Genome organization and replication

The S segment encodes N, the M segment encodes GPC, and the L segment encodes L (Figure 1 Shaspivirus).

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

Biology

The original genome sequence of SySV1 was obtained from brown sailor spiders (araneid Neoscona nautica (L. Koch, 1875)) (Li et al., 2015). Replication-competent shaspivirus isolates have not yet been obtained, and hence shaspivirus biology remains to be elucidated.

Species demarcation criteria

The genus currently includes only a single species.