New insights about ORF1 coding regions support the proposition of a new genus comprising arthropod viruses in the family Totiviridae

• Arthropod totiviruses have peculiar characteristics.
• At least two additional coding regions are present in ORF1.
• Two exclusive additional proteins can mediate viral infection mechanisms.
• Arthropod totiviruses can be classified as a new genus.

Analyzing the positions of 2A-like polypeptide cleavage sites in all available genomes of arthropod totiviruses we propose the limits of all ORF1 coding sequences and observed that two proteins previously predicted in infectious myonecrosis virus genome are unique in the arthropod totiviruses group. A putative protein cleavage site upstream the major capsid protein was also identified only in these genomes. In addition, protein models generated using ab initio and threading approaches revealed conserved structures possibly related to formation of viral protrusions and RNA packaging, clarifying the mechanisms involved in the extracellular transmission. These data appoints that the group formed by arthropod totiviruses are sufficient distinctive to be clustered in new genus belonging to the Totiviridae family, in agreement with previous phylogenetic analysis.