Amino acid sequence similarity of the VP7 protein of human rotavirus HCR3 to that of canine and feline rotaviruses

The sequence of the VP7 gene of human rotavirus strain HCR3 was determined and its predicted amino acid sequence was compared with that of other rotavirus strains. The VP7 gene is 1062 nucleotides long and contains a single open reading frame of 981 nucleotides capable of encoding a protein of 326 amino acids. The VP7 amino acid sequence similarity of strain HCR3 to those of various human and animal G3 serotypes ranged from 88.7 to 99-4 %, and from 60,4 to 88.3 % to strains representing each of the other 13 G serotypes. Alignment of four variable regions [VR4, VRS(A), VR7(B) and VR8(C)] of HCR3 with those of G3 strains of different host species howed that HCR3 possesses a sequence almost identical to that of canine rotaviruses and feline rotavirus strain CAT97 in all four regions. A con-siderable divergence in regions VR4, VR7(B) and VR8(C) was found with strains of human, mouse, monkey, horse and rabbit rotaviruses. This observation together with results of our previous study on VP4 indicated that human rotavirus HCR3 is genetically more closely related to animal rotaviruses than to other human rotaviruses. Rotaviruses are the major cause of acute viral gas-troenteritis n human infants and in the young of a wide variety of mammalian and avian species (Kapikian & Chanock, 1990). Two outer capsid proteins, VP7 and VP4, are associated with the induction of neutralizing antibodies (Hoshino et al., 1985; Offit & Blavat, 1986). Rotavirus erotypes were initially established by neutral-ization assay based on the antigenic specificities of VP