Whole Genome Sequences of the Wildtype AU-1 Rotavirus A Strain: The Prototype of the AU-1-like Genotype Constellation

Most human rotaviruses belong to the Wa-like, DS-1-like, or AU-1-like genotype constellation. The AU-1-like constellation, albeit minor, captured attention because its prototype strain AU-1 originated from feline rotavirus, leading to the concept of interspecies transmission of rotavirus. The AU-1 genome sequence determined by various laboratories over the years has documented two conflicting VP7 sequences in the GenBank. As culture-adaptation may introduce changes in the viral genome, the original fecal (wild-type) and the seed stock of culture-adapted AU-1 genomes were sequenced using the Illumina’s MiSeq platform to determine the authentic AU-1 sequence and to identify what mutational changes were selected during cell-culture adaptation. The wild-type and culture-adapted AU-1 genomes were identical except for one VP4-P475L substitution. Their VP7 gene was 99.9% identical to the previously reported AU-1 VP7 under accession number AB792641 but only 92.5% to that under accession number D86271. Thus, the wild-type sequences determined in this study (accession numbers OR727616-OR727626) should be used as the reference. The VP4-P475L mutation was more likely incidental than inevitable during cell-culture adaptation. This was the first study in which the whole genomes of both wild-type and cultured RVA strains were simultaneously determined by deep sequencing.