Identification of the gene encoding the group B rotavirus VP7 equivalent: primary characterization of the ADRV segment 9 RNA.

Gene segment 9 of the adult diarrheal rotavirus, ADRV, has been cloned, and the full-length gene 9 cDNA has been sequenced. Sequences at the 5' and 3' termini of the gene 9 double-stranded RNA were confirmed by direct RNA sequencing. The ninth RNA segment is 814 bases in length with a single open reading frame beginning at base 10 and terminating at base 757. The encoded polypeptide contains 249 amino acids with a calculated molecular weight of 28.5 kDa. The protein contains three potential N-linked glycosylation sites and a hydrophobic signal-like sequence at its amino terminus. A search of the NBRF protein data base with the encoded polypeptide revealed extensive similarities with VP7 proteins from a number of group A rotaviruses. Direct comparisons of the ADRV gene 9 polypeptide and the group A rotavirus VP7 demonstrate that the two proteins share 78% amino acid similarity and 28% identity as well as predicted secondary structure similarities. These findings suggest that the ADRV gene segment 9 encodes the VP7 polypeptide equivalent of group A rotaviruses.