Nucleotide sequence of the VP7 gene of human rotavirus isolated in Calcutta, India: Possible emergence of a new subtype of serotype I

We have investigated the serotype-specific glycoprotein gene (VP7) of a sho rt electropherotype and subgroup I rotavirus (ID 45/2) recovered from a chi ld suffering from acute diarrhea. The nucleotide sequence of the human (ID 45/2) rotavirus genome segment 8/9, which encodes the serotype-specific gly coprotein (VP7) has been determined. Comparison of the nucleotide sequence of ID 45/2 to the sequences of other rotaviruses belonging to different ser otypes (G1-14) revealed only 67-78% identity. Comparison of the deduced ami no acid sequence of ID 45/2 VP7 protein to the sequences of other VP7 prote ins showed that the majority of the amino acid differences are clustered at the N-terminus (residues 1-49), with a positional shift of the initiation codons as well as possession of one stretch of hydrophobic signal peptide i nstead of two. On the basis of other rotaviral characteristics, such as the conserved cysteine and proline residues together with the potential glycos ylation site, it is proposed that this local strain (ID 45/2) might represe nt a new subtype related to serotype G1. Dot blot hybridization using ID 45 /2 cDNA as probe indicated the prevalence of this strain in Eastern India.