Abstract:

The family Tetraviridae is comprised of (+) ssRNA viruses and divided into the Nudaurelia β-like viruses and Nudaurelia ω like viruses. The viruses of these two genera have different genomic organization. The β-like viruses have monopartite genomes and use a subgenomic RNA to express the structural protein, while the β-like viruses have bipartite genomes composed of two unique RNA molecules, which encode the replicases and the structural proteins, respectively. There is a tRNA-like structure on the 3′-termini of the tetravirus genomic RNAs. The coat proteins of the ω like viruses show 66%－86% amino acid sequence identities, while the overall homologies between the coat proteins of the β-like viruses are  much lower. When the coat protein ORFs of tetraviruses are expressed in insect cells, they are all able to form virus-like particles. The paper also reviewed advances on replication mechanism of tetrviruses and the evolutionary relationship among tetraviruses and others.

Key words: Insect, tetravirus, genome structure, tRNAlike structure, phylogeny