Sequence analysis of VP4 and VP7 genes of nontypeable strains identifies anew pair of outer capsid proteins representing novel P and G genotypes in bovine rotaviruses

During a limited epidemiological study, the serotype specificities of sever al isolates of bovine rotavirus, exhibiting identical electropherotypes, fr om a single cattle farm near Bangalore, India, could not be determined usin g a panel of serotyping monoclonal antibodies (MAbs) specific for G serotyp es 1-6 and 10. To determine the genotypes of these isolates, the nucleotide sequences of the genes encoding the outer capsid proteins VP4 end VP7 of t wo representative isolates, Hg18 and Hg23, were determined. The correspondi ng gene sequences from the two isolates were identical, indicating that the se isolates represented a single strain of bovine rotavirus. Comparison of the VP4 nucleotide (nt) and the deduced amino acid (aa) sequences with thos e of several human and animal rotavirus strains representing all of the cur rently recognized 20 different VP4 (P) genotypes revealed low nt and as seq uence identities of 61.0 to 74.2% and 57.9 to 78.2% for VP4. The percentage s of amino acid homology for the VP8* and VP5* regions of VP4 were 37.7 to 67.9 and 68.1 to 84.2%, respectively. The nt and aa sequences of the VP7 ge ne were also distinct from those of human and animal strains belonging to t he previously established 14 VP7(G) serotypes (65.9 to 75.5% nt and 59.5 to 77.6% aa identities). These findings suggest the classification of the VP4 and VP7 genes of the bovine isolates represented by Hg18 as new P and G ge notypes and provide further evidence for the vast genetic/antigenic diversi ty of group A rotaviruses, (C) 2000 Academic Press.