Common evolutionary origin of aquareoviruses and orthoreoviruses revealed by genome characterization of Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus (genus Aquareovirus, family Reoviridae)

Abstract

Full-length and partial genome sequences of four members of the genus Aquareovirus, family Reoviridae (Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus) were characterized. Based on sequence comparison, the unclassified Grass carp reovirus was shown to be a member of the species Aquareovirus C. The status of golden ide reovirus, another unclassified aquareovirus, was also examined. Sequence analysis showed that it did not belong to the species Aquareovirus A or C, but assessment of its relationship to the species Aquareovirus B, D, E and F was hampered by the absence of genetic data from these species. In agreement with previous reports of ultrastructural resemblance between aquareoviruses and orthoreoviruses, genetic analysis revealed homology in the genes of the two groups. This homology concerned eight of the 11 segments of the aquareovirus genome (amino acid identity 17-42 %), and similar genetic organization was observed in two other segments. The conserved terminal sequences in the genomes of members of the two groups were also similar. These data are undoubtedly an indication of the common evolutionary origin of these viruses. This clear genetic relatedness between members of distinct genera is unique within the family Reoviridae. Such a genetic relationship is usually observed between members of a single genus. However, the current taxonomic classification of aquareoviruses and orthoreoviruses in two different genera is supported by a number of characteristics, including their distinct GMC contents, unequal numbers of genome segments, absence of an antigenic relationship, different cytopathic effects and specific econiches.

Cloning and characterization of the grass carp (Ctenopharyngodon idella) Toll-like receptor 22 gene, a fish-specific gene

“…Indeed, a previous study suggested that fgTLR3 and fgTLR22 may recognize different sizes of dsRNA with TLR22 preferentially recognizing long RNA molecules. An additional difference was that fgTLR22 localized to the surface of the cell membrane while fgTLR3 was localized inside the cell [23] being consistent with differences in function of TLR3 and TLR22. In the study presented here, we further investigated the function of these TLRs by comparing similarities and differences between CiTLR22 and CiTLR3 in tissue-specific expression profiles, following infection with GCRV and during early embryonic development.…”

“…Grass carp (Ctenopharyngodon idella) is an important aquaculture species in China, but tremendous economical loss is often caused by infections with grass carp reovirus (GCRV), a dsRNA virus [22,23]. Preventing this infectious disease is still difficult to date.…”

An improved RT-PCR assay for rapid and sensitive detection of grass carp reovirus

“…Analysis of genome sequence and 3D reconstruction of protein structure indicates that structural similarities exist between GCRV and other reovirus and aquareoviruses, but there are many differences, which may be due to genus-specific divergence related to viral-host interactions. Sequence analysis indicates that the outermost VP7 capsid protein encoded by the S10 segment of the genome is the most divergent of all the structural proteins (Attoui et al, 2002;Cheng et al, 2008), and therefore segment 10 should be the optimum choice for RT-PCR detection. Li et al (1997) developed previously a GCRV RT-PCR detection method based on segment 6 and segment 9, but their two primer pairs could only detect one of two GCRV isolates, GCRV-861; GCRV-873, the most virulent strain, could not be detected.…”

“…Like many other reoviruses, GCRV is a multilayered spherically structured particle that contains a genome of 11 segments of dsRNA (named S1-S11) that encode 7 structural proteins (VP1-VP7) and 5 nonstructural proteins (Attoui et al, 2002;Fang et al, 2005Fang et al, , 2008Cheng et al, 2008Cheng et al, , 2009). …”

Cell-Cell Membrane Fusion Induced by p15 Fusion-associated Small Transmembrane (FAST) Protein Requires a Novel Fusion Peptide Motif Containing a Myristoylated Polyproline Type II Helix

“…Additional fusogenic orthoreoviruses continue to be discovered (2), and the related genus Aquareovirus also contains members that induce syncytium formation (3). Nonenveloped viruses lack a lipid membrane and virus entry into cells does not involve a membrane fusion event.…”