Sequence analysis of NSP4 gene of human rotavirus allows classification into two main genetic groups

Abstract

The rotavirus nonstructural glycoprotein NSP4 may represent the first identified viral enterotoxin. We have sequenced reverse transcription-polymerase chain reaction (RT-PCR)-generated fragments of 16 NSP4 genes of human rotavirus (HRV) strains from six different countries, representing seven different G and P type combinations. Based on the amount of sequence divergence between these and 11 previously sequenced NSP4 genes of human and animal rotaviruses, three distinct genetic groups could be recognized. Most strains within a group were closely related to each other at the nucleotide (nt) and amino acid (aa) levels (usually <10% divergence) but more distantly related (maximum 30.0% nt divergence and 24.7% aa divergence) to members of the other groups. Intergroup variation occurred in two highly variable regions of NSP4 (aa 16-34 and aa 131-148). The NSP4 "toxic peptide" (aa 114-135) exhibited aa variation at its carboxy terminus both within and between genetic groups. The largest group (genetic group II) contained HRV strains of subgroup II specificity (including genotypes P[8]G1, P[8]G3, P[6]G3, and P[8]G5 and serotype P8[11]G9), and the smaller group (genetic group I) contained HRV strains of subgroup I specificity (genotype P[4]G2). The NSP4 sequence of the rhesus rotavirus vaccine strain was distinct from all other strains and formed the third group (genetic group III). The NSP4 genes of animal rotaviruses UK, NCDV, and SA11 (genetic group I) and YM (genetic group II) and two possible human-animal rotavirus reassortant strains, Brazilian P[8]G5 and Indian P[11]G9 (genetic group II), could also be classified into one of these groups, suggesting a close evolutionary relationship between human and animal NSP4 genes. These results will facilitate studies of the host immune response to NSP4, which may be relevant to future HRV vaccine design.

Molecular characterization of human rotavirus vaccine strain CDC-9 during sequential passages in vero cells

“…Genes of some wild-type viruses such as rotaviruses, [22][23][24][25] poliovirus, [26][27][28] varicella zoster virus, 29 porcine reproductive and respiratory syndrome virus 30 and transmissible gastroenteritis virus 31 and their attenuated forms derived by sequential passages in cell culture have been characterized to determine the molecular basis of attenuation. In this study, we isolated a G1P [8] human rotavirus strain CDC-9 from a child who had a mixed rotavirus G1P [8] and G2P [4] infection.…”

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

“…For amplification of the VP8* fragment, the primer pair con2/con3 was used (Gentsch et al, 1992). For VP6 and NSP4 gene amplification, the primer pairs VP6F/VP6R and NSP4F/NSP4R were used, respectively (Cunliffe et al, 1997;Iturriza-Gó mara et al, 2002). For animal rotavirus strains, previously published VP6 primers (Iturriza-Gó mara et al, 2002) were modified slightly as shown in Table 2.…”

Molecular Epidemiology of Rotavirus Diarrhea among Children in Saudi Arabia: First Detection of G9 and G12 Strains

“…Extensive sequence analysis has shown that human and animal NSP4 genes fall into five genetic groups (A to E), and strains tend to cluster within genotypes according to their species of origin (4,7,(15)(16)(17). Thus, examination of the NSP4 genes provides useful information in analyzing unusual isolates.…”