Family: Arenaviridae

Genus: Antennavirus

Distinguishing features

Wēnlǐng frogfish arenaviruses 1 and 2 (WlFAV-1/2) are the only currently classified antennaviruses. Both viruses have been found in fish (Shi et al., 2018). Notably, antennaviruses have genomes consisting of 3, genomic segments and likely do not encode the zinc-binding matrix (Z) protein, which is encoded by mammarenaviruses and reptarenaviruses. 

Virion

Virons are unknown. 

Nucleic acid

Viruses have 1 ambisense and 2 negative-sense single-stranded RNA segments. The termini of the RNAs contain inverted complementary sequences, likely encoding transcription and replication initiation signals (Shi et al., 2018). 

Proteins

Based on sequence data only, viruses likely express 4 structural proteins: nucleoprotein (NP), glycoprotein precursor (GPC), RNA-directed RNA polymerase (L), and a protein of unknown function (Shi et al., 2018). 

Genome organization and replication

The S RNA of antennaviruses encodes the nucleoprotein (NP); the M RNA encodes the glycoprotein precursor (GPC) and an unknown protein; and the L RNA encodes the RNA-directed polymerase (Figure 1. Antennavirus) (Shi et al., 2018). 

Figure 1. .Antennavirus.  Schematic representation of the trisegmented antennavirus genome organization. The 5'-and 3'-ends of all segments (S, M and L) are complementary at their termini, likely promoting the formation of circular ribonucleoprotein complexes within the virion. GPC, glycoprotein precursor; L, RNA-directed RNA polymerase; NP, nucleoprotein. Intergenic regions (IGRs), which form hairpin structures (not shown), separate open reading frames.

Biology

Antennaviruses were discovered in 2011 by next generation sequencing of samples taken from striated frogfish (Antennarius striatus (G. Shaw, 1794)) captured by fishing trawlers in the East China Sea (Shi et al., 2018). 

Derivation of names

Antennavirus: from Antennarius striatus, the fish species to which the presumed host of WlFAV-1 and WlFAV-2, striated frogfish, has been assigned (Shi et al., 2018). 

Species demarcation criteria

The parameters used to assign viruses to different species in the genus are:

• virus shares less than 80% nucleotide sequence identity in the S segment and less than 76% identity in the L segment;
• association of the virus with a distinct main host or a group of sympatric hosts;
• dispersion of the virus in a distinct defined geographical area;
• association (or not) with human disease;
• virus shares less than 88% NP amino acid sequence identity (Radoshitzky et al., 2015). 

Relationships within the genus

Phylogenetic relationships within the genus are unknown due to absence of sequence information beyond two single genome sequences of two viruses. 

Related, unclassified viruses

Virus names and abbreviations are not official ICTV designations.