Family: Natareviridae

Jens H. Kuhn, Nolwenn M. Dheilly, Sandra Junglen, Sofia Paraskevopoulou (Σοφία Παρασκευοπούλου), Mang Shi (施莽) and Nicholas Di Paola

The citation for this ICTV Report chapter is the summary to be published as Kuhn et al., (2023):

ICTV Virus Taxonomy Profile: Jingchuvirales, Journal of General Virology 2023, (in press)

Corresponding author: Nicholas Di Paola (nicholas.dipaola.civ@health.mil) 
Edited by: Jens H. Kuhn and Stuart G. Siddell
Posted: November 2023

Summary

Natareviridae is a family for a negative-sense RNA virus with a genome of about 12.9 kb (Table 1.Natareviridae). This virus was found in crustaceans in China. The family includes a single genus with one species for this virus. The natarevirid genome contains four open reading frames (ORFs) that encode a nucleoprotein (NP), two glycoproteins (GPs), and a large (L) protein containing an RNA-directed RNA polymerase (RdRP) domain.

Table 1.Natareviridae. Characteristics of members of the family Natareviridae

Virion

Morphology

Unknown.

Nucleic acid

Natarevirids have nonsegmented linear negative-sense RNA genomes with total lengths of about 12.9 kb (Li et al., 2015).

Genome organization and replication

Natarevirid genomes have four ORFs that encode two glycoproteins (GPs), a nucleoprotein (NP), and a large (L) protein (Li et al., 2015) (Figure 1.Natareviridae). The replication cycle of natarevirids remains to be elucidated.

Figure 1.Natareviridae. Genome organization of Wēnzhōu crab virus 3. ORFs are colored according to the predicted protein function. GP, glycoprotein gene; NP; nucleoprotein gene; L, large protein gene.

Biology

The only classified natarevirid, Wēnzhōu crab virus 3 (WzCVV3), has been associated with portunid crustaceans (Charybdis japonica (A. Milne-Edwards, 1861)) sampled in China (Li et al., 2015). The presence of endogenized natarevirid elements (in particular, GP-gene-derived nucleic acids) in arthropod genomes indicates that natarevirids are millions of years old (Dezordi et al., 2023).

Derivation of names

Charybdivirus, charybdis: from Charybdis, a sea monster in Greek mythology

Natareviridae: from nata, an inflection of the Latin nato, meaning “swim, float”

Genus demarcation criteria

Not applicable (the family includes only a single genus).

Species demarcation criteria

Not applicable (the only genus includes one species).

Relationships within the family

Phylogenetic relationships of members of the family Natareviridae are shown in Figure 2.Natareviridae.

Figure 2.Natareviridae. Phylogenetic relationships of natarevirids. Maximum-likelihood tree (midpoint-rooted) inferred by using large protein gene (L) sequences. Sequences were initially aligned by MAFFT version 7 (https://mafft.cbrc.jp/alignment/software/) in Geneious version R9 (http://www.geneious.com) and realigned using ClustalW (https://www.genome.jp/tools-bin/clustalw). The tree was estimated using PhyML 3.0 (http://www.atgc-montpellier.fr/phyml/ , a subtree pruning and regrafting (SPR) topology searching algorithm, and a Bayes branch support algorithm. Numbers near nodes on the trees indicate bootstrap values as percentages. Tree branches are scaled to nucleotide substitutions per site (scale bar). Two mononegavirals were included as an outgroup.

Relationships with other taxa

Viruses in the family Natareviridae are most closely related to jingchuviral aliusvirids, chuvirids, crepuscuvirids, and myriavirids (Li et al., 2015, Di Paola et al., 2022).