[NSP5/NSP6 of rotavirus strain TB-Chen and preliminary genotyping analysis].
Strain TB-Chen is a group A rotavirus (RV) isolated from a Chinese infant suffering from gastroenteritis in hospital. The NSP5 and NSP6 of strain TB-Chen are encoded by the 10th gene segment (816bp in whole length) of the viral genome. The results obtained in this study showed that the NSP5 was encoded in the first open-reading-frame (ORF) of the gene segment (from 22bp to 624bp), and NSP6 was encoded in the second ORF (from 80bp to 355bp). The NSP5 protein consisted of 200 amino acid residues with a putative molecular mass of 21.9 kD, and a putative isoelectric point of 7.86. The NSP6 protein consisted of 92 amino acids with a putative molecular mass of 11 kD, and a putative isoelectric point of 9.65. This study further analyzed phylogenetic relationship of the NSP5/NSP6 ORF nucleotide sequence. The results showed that the NSP5s of group A rotavirus could be at least classified into 7 genotypes (H1-H7), the NSP6s could be at least classified into 8 genotypes (hl-h8); the genotypes of the NSP5 and NSP6 derived from strain TB-Chen was classified as H2 and h2. This was the first report on the genotype classification of the NSP6 of group A RVs, and it was proposed English letter "h" to represent genotype of the NSP6, e. g. strain 69M classified as H7h7, strains Wa and KU classified as H1h8.