South African G4P[6] asymptomatic and symptomatic neonatal rotavirus strains differ in their NSP4, VP8, and VP7 genes

• Published in: Journal of medical virology Vol. 62; no. 2; pp. 208 - 216
• Main Authors: Pager, Cara T., Alexander, Jennifer J., Steele, A. Duncan
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.10.2000; Wiley-Liss
• Subjects: Amino Acid Sequence; Antigens, Viral; Biological and medical sciences; Capsid - chemistry; Capsid - genetics; Capsid Proteins; Diarrhea, Infantile - physiopathology; Diarrhea, Infantile - virology; Fundamental and applied biological sciences. Psychology; Genes, Viral; Genetics; Glycoproteins - chemistry; Glycoproteins - genetics; Human viral diseases; Humans; Infant, Newborn; Infectious diseases; Medical sciences; Microbiology; Molecular Sequence Data; neonatal infection; NS4 gene; NSP4; RNA-Binding Proteins - chemistry; RNA-Binding Proteins - genetics; Rotavirus; Rotavirus - genetics; Rotavirus Infections - physiopathology; Rotavirus Infections - virology; South Africa; Toxins, Biological; Viral diseases; Viral diseases of the digestive system; Viral Nonstructural Proteins - chemistry; Viral Nonstructural Proteins - genetics; Virology; VP7; VP7 gene; VP8; VP8 gene; South Africa(Republic); Africa; South Africa; Human; Genetic variability; Rotavirus; Human rotavirus; Nucleotide sequence; Diarrhea; Reoviridae; Infection; Virus; Pathogenicity; Symptomatology; Newborn; Viral disease; Digestive diseases; Intestinal disease; Aminoacid sequence
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/1096-9071(200010)62:2<208::AID-JMV12>3.0.CO;2-K

Over the past decade, a G4P[6] strain has been found to be circulating in different neonatal wards in the Pretoria area. This endemic strain was associated with both asymptomatic and symptomatic infection, providing the opportunity to undertake a molecular study of some of the putative “virulence” genes. The genes encoding NSP4, VP8*, and VP7 of two asymptomatic and two Symptomatic strains were sequenced and compared with ST3. Within each of these genes, amino acid substitutions unique to South African strains were recorded. Four conserved amino acid differences between asymptomatic and symptomatic strains at aa 82 (serine to leucine), aa 114 (aspartic acid to glutamic acid), aa 138 (proline to threonine), and aa 169 (leucine to serine) were identified within the NSP4 gene. The hypervariable region of VP8* exhibited 10 specific amino acid differences (at aa 73, 78, 98, 111, 116, 142, 145, 167, 169, and 188) between asymptomatic and symptomatic strains, while three amino acid substitutions within VP7 were noted. These changes to VP7 occurred within the glycosylation site at aa 70 (leucine to serine), at antigenic region A (aa 96, asparagine to threonine), and at aa 318 (aspartic acid to glycine). It may be speculated that these changes are specific to G4P[6] strains. Furthermore, the observed substitutions may also be particular to South African strains. NSP4, VP8*, and VP7 have been associated with virulence and the amino acid substitutions within these genes correlate with both asymptomatic and symptomatic infection observed in neonates. J. Med. Virol. 62:208–216, 2000. © 2000 Wiley‐Liss, Inc.