Family: Peribunyaviridae

Genus: Lakivirus

Distinguishing features

Lakivirus RNA was detected in a single Wyeomyia complosa mosquito from Mexico in 2008. The lakivirus genome does not encode any non-structural proteins and displays a significantly truncated Gc protein, similar to herbeviruses. Additionally, the sequences of the RNA termini are identical to those of orthobunyaviruses (Kopp et al., 2019). No viruses belonging to the genus have been isolated.

Virion

Morphology

Not described.

Nucleic acid

Lakivirus RNA displays the peribunyavirus-typical tripartite, negative-sense genome organization. The terminal nucleotides of each segment (S, M, and L) occur in a canonical, conserved sequence (in coding sense) 5′-AGTAGTGT…ACACTACT-3′, which is similar in sequence to that of members of the genus Orthobunyavirus (Kopp et al., 2019).

Proteins

Lakivirus genomes encode four structural proteins: L, the glycoproteins Gn and Gc, and the nucleocapsid protein N (Table 2.Peribunyaviridae). These viruses do not encode any non-structural proteins (Figure 1.Lakivirus). The glycoprotein is significantly shorter than that of other peribunyaviruses. Similar to herbeviruses, the lakivirus Gc protein is truncated and lacks the variable region. The Gc fusion protein is more divergent than other peribunyaviruses (Kopp et al., 2019).

Lipids

Not described.

Carbohydrates

The lakivirus glycoprotein is predicted to have 2 N-glycosylation sites, one on each Gn and Gc (Kopp et al., 2019).

Genome organization and replication

The lakivirus genome is similar to the genomes of all peribunyaviruses and includes three segments. The S, M, and L segments encode N, Gn and Gc, and L proteins, respectively. The L protein includes an endonuclease in the N-terminus, and six conserved RNA-directed RNA polymerase motifs including pre-A, and motifs A–E in the central region. The lakivirus genome does not encode either of the non-structural proteins NSs or NSm, similar to herbevirus and lambavirus genomes (Kopp et al., 2019). Details of virus replication are unknown.

Figure 1. Lakivirus. Lakivirus coding strategy. vcRNAs are depicted in 3′→5′ direction and mRNAs are depicted in a 5′→3′ direction. Coloured boxes on the mRNAs depict ORFs that encode the N, nucleocapsid protein; Gn and Gc, external glycoproteins; L, large protein.

Biology

One lakivirus, Lakamha virus, was detected in a single Wyeomyia complosa mosquito. No viruses belonging to the genus have been isolated but are thought to be insect specific (Kopp et al., 2019).

Species demarcation criteria

Not defined as the genus currently includes only a single species.