Comparison of the Rotavirus Gene 6 from Different Species by Sequence Analysis and Localization of Subgroup-Specific Epitopes Using Site-Directed Mutagenesis

Abstract

The nucleotide sequence of gene 6 encoding the rotavirus major capsid protein VP6 of EDIM strain (EW) was determined and compared to that of 20 previously reported strains with known subgroup specificities. Multiple alignments of amino acid sequences exhibited a high level of sequence conservation (87 to 99.2%). Site-specific mutagenesis experiments were undertaken to localize regions involved in subgroup specificity. Amino acid positions 305, 315, and a region 296-299 (or 301 for equine strain H-2) were identified as contributing to subgroup epitopes. A single amino acid mutation at position 305 or 315 was sufficient to change the subgroup specificity of EW VP6 protein from non I/II to subgroup I- or subgroup II-like, respectively. Mutation at these sites may be another important mechanism for subgroup variation, along with gene reassortment.

Human, porcine and bovine rotaviruses in Slovenia: evidence of interspecies transmission and genome reassortment

“…In contrast, all human rotavirus strains phylogenetically related to rotavirus strains of subgroup II specificity have been grouped together in the NSP4-B genotype. It was demonstrated that even closely related VP6 sequences of porcine rotavirus strains could be of different subgroups (Tang et al, 1997). Thus, we cannot speculate on the subgroup specificity of our porcine rotavirus strains based only on phylogenetic analysis of the VP6 fragment.…”

“…The amino acid identity of these two strains with other strains of NSP4-B genotype was less than 90 % (data not shown). Human and animal strains were also analysed in a region spanning aa 241-367 (nt 747-1126 of the VP6 gene) implicated in subgroup specificity (Tang et al, 1997). As shown in the phylogenetic tree of VP6 (Fig.…”

Group A rotavirus genotypes and the ongoing Brazilian experience: a review

“…The SG specificities are determined by amino acids located at positions 305, the region between amino acids positions 296 and 299 (SGI) and amino acid position 315 (SGII) (López et al 1994, Tang et al 1997. Many epidemiological studies have used subgrouping enzyme immunoassays (EIAs).…”

“…Many epidemiological studies have used subgrouping enzyme immunoassays (EIAs). Based upon these analyses, most human isolates fall into SGII (Arista et al 1990, Gómara et al 2001, while most animal isolates fall into SGI (Tang et al 1997). …”

Analysis of the VP6 gene of human and porcine group A rotavirus strains with unusual subgroup specificities

“…In the case of SG II, the mutation of two contiguous amino acids (Ala305 Asn306 to Asn305 Ala306) in the VP6 protein of porcine rotavirus YM (SG I) enables the protein to be recognized efficiently by the SG II MAb 631/9, while losing its capacity to interact with SG I MAb 255/60. Furthermore, it has been proposed that an Ala residue at positions 172 and 305 contribute to determining reactivity to SG I MAb (MAb 255/60), whereas a Glu residue at position 315 contributes to reactivity to SG II MAb (MAb 631/9) [Tang et al, 1997]. Analysis of the VP6 protein, which encompasses the amino acid positions in the regions implicated in the recognition by SG-specific MAbs, revealed that deduced amino acid sequences of human rotavirus strains determined serologically as SG II, SG (I þ II), or SG non-(I þ II) are indistinguishable from each other [Iturriza-Gomara et al, 2002].…”