Distinctness of NSP1 gene of human rotavirus AU-1 from NSP1 gene of other human genogroups

Human rotavirus strain AU-1 has a genomic RNA constellation distinct from that of either the Wa or DS-1 genogroup and thus, represents the third human rotavirus genogroup. Nucleotide sequence analysis of the non-structural protein 1 (NSP1) of AU-1 revealed that it was only 53-57% identical at the amino acid level with strains belonging to either the Wa or the DS-1 genogroup. This result confirmed and extended the earlier observation that the grouping based on the NSP1 sequence similarity is usually in good agreement with classification by genogroup. Phylogenetic analysis placed the AU-1 NSP1 gene on the bovine NSP1 branch, although more than 13% amino acid difference was observed.