Sequence analysis of VP1 and VP7 genes suggests occurrence of a reassortant of G2 rotavirus responsible for an epidemic of gastroenteritis.

Zao, Chih-Ling; Yu, Wan-Nien; Kao, Chuan-Liang; Taniguchi, Koki; Lee, Chin‐Yun; Lee, Chun-Nan

doi:10.1099/0022-1317-80-6-1407

Cited by 45 publications

(44 citation statements)

References 43 publications

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“…Subsequent analysis of rotavirus strains from Tunisia in 2000, however, revealed that 11 of 20 (55%) were G2P [4] The phylogeny of serotype G2 strains from the African continent revealed two sublineages (IIc and IId), the strains of which were more likely to be isolated in seasons when G2 was predominant than strains clustering in the remaining two sublineages (IIa and IIb). Hybridization analysis of these serotype G2 strains will be conducted to determine whether these strains may be related to the Taiwanese G2 isolates responsible for the epidemic outbreak of rotavirus-associated diarrhea in 1993 (27,40).…”

Section: Discussionmentioning

confidence: 99%

Antigenic and Genetic Characterization of Serotype G2 Human Rotavirus Strains from the African Continent

Page

Steele

2004

J Clin Microbiol

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Serotype G2 rotavirus strains were isolated in seven countries on the African continent during 1999 and 2000. To investigate the associated DS-1 genogroup characteristics, subgroup (VP6) enzyme-linked immunosorbent assay, polyacrylamide gel electrophoresis, and P genotyping were performed on 10 G2 strains. The antigenic and genetic variation of the gene encoding the major neutralization glycoprotein (VP7) was also investigated by using G2-specific monoclonal antibodies and sequence analysis. Alterations in the characteristic DS-1 genogroup gene constellations were more likely to occur in the VP4 gene, and three genotypes were observed: P[4], P[6], and a dual P[4]-P[6] type. The failure of G2-specific monoclonal antibodies to type African G2 strains was more likely due to improper storage of the original stool, although G2 monotypes were detected. Phylogenetic analyses revealed clusters of serotype G2 strains that were more commonly associated with seasons during which G2 was predominant. No rotavirus vaccine trials have been conducted in an area where G2 strains were the predominant circulating serotype, and the continued surveillance of rotavirus epidemics in Africa will be preparation for future vaccine implementation in an area that clearly needs these preventative medicines.

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Section: Discussionmentioning

confidence: 99%

Antigenic and Genetic Characterization of Serotype G2 Human Rotavirus Strains from the African Continent

Page

Steele

2004

J Clin Microbiol

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“…This would also allow researchers to investigate at a molecular level whether and to what extent VP6 genes are involved in reassortment events shown to occur in nature during cocirculation of different human and animal rotavirus strains (14,25,26).…”

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Molecular Characterization of VP6 Genes of Human Rotavirus Isolates: Correlation of Genogroups with Subgroups and Evidence of Independent Segregation

Iturriza‐Gómara

Wong

Blome

et al. 2002

J Virol

258

217

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A reverse transcription-PCR (RT-PCR) was established to amplify a 379-bp cDNA fragment (nucleotides 747 to 1126, coding for amino acids 241 to 367) of the VP6 gene of group A rotaviruses associated with subgroup (SG) specificity. Thirty-eight human rotavirus strains characterized with SG-specific monoclonal antibodies were subjected to VP6-specific RT-PCR, and PCR amplicons were used for sequencing. Nucleic acid sequencing and phylogenetic analysis of the VP6 amplicons revealed two clusters, or genogroups. Two genetic lineages were distinguished within genogroup I, consisting of strains serologically characterized as SG I, and three genetic lineages were distinguished within genogroup II, composed of strains serologically characterized as SG II, SG I ؉ II, and SG non-I, non-II. Subgrouping of rotaviruses by means of serological methods may result in strains not being assigned the correct SG or in a failure of strains to subgroup. Molecular characterization of the SG-defining region of VP6 provided evidence for independent segregation of the rotavirus genes encoding VP4, VP6, and VP7.Rotaviruses are triple-layered particles of the Reoviridae family which are classified into groups (A to E) and subgroups (SG) according to the presence of epitopes on the middle-layer protein VP6 (16). VP6 is a trimeric protein that interacts with the inner-layer protein VP2 and with the two outer-layer proteins VP7 and VP4 (20). Most human rotavirus infections are caused by rotaviruses of group A. Within this group, SG I, II, I ϩ II, and non-I, non-II have been defined according to the presence or absence of two distinct epitopes reactive with one, both, or neither of the monoclonal antibodies (MAbs) 255/60 and 631/9 (11). Subgrouping enzyme-linked immunosorbent assays (ELISAs) have been used extensively in epidemiological studies. The rotaviruses most commonly found in humans belong to SG II (2,4,8,14,19), while SG I is common among animal rotaviruses (18,23).Previous studies have mapped SG I specificity to amino acid (aa) position 305 and the region between positions 296 and 299 and SG II specificity to residue 315 (18, 23). It is still unclear whether SG specificity is determined by linear or conformational epitopes, although there is some evidence that the epitopes recognized by SG-specific MAbs are conformational and are present only in the trimeric form of VP6 (9). Amino acid substitutions that are quite distant in the linear molecule may affect the conformation of the epitopes.Serological characterization of the surface proteins VP7 and VP4 has been shown to be unreliable due to antigenic drift through the accumulation of point mutations (7,12,21). It is possible that VP6 will undergo similar antigenic changes, resulting in poor reactivity in serological subgrouping assays.The aims of this work were to determine the SG of rotavirus strains on the basis of cDNA sequences of a fragment of the VP6 genes, to investigate correlations between molecular and serological subgrouping methods, and to study the variability of the VP6 ge...

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“…These mutants can therefore be regarded as antibody escape mutants that are widely dispersed geographically and are identical to G2 strains isolated post-1993 in Taiwan, where an epidemic caused by G2 rotavirus strains in 1993 was reported (24). It was suggested that the epidemic in Taiwan was associated with an alteration in pathogenicity, perhaps conferred by reassortment (24). However, the explosive reemergence of G2 strains in this region may have been due to immune evasion as a consequence of altered antigenicity conferred by the amino acid substitution at position 96 of antigenic region A.…”

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Amino Acid Substitution within the VP7 Protein of G2 Rotavirus Strains Associated with Failure To Serotype

et al. 2001

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Rotavirus strains collected in the United Kingdom during the 1995-1996 season and genotyped as G2 by reverse transcription-PCR failed to serotype in enzyme-linked immunosorbent assays using three different G2-specific monoclonal antibodies. The deduced amino acid sequences of the antigenic regions A (amino acids 87 to 101), B (amino acids 142 to 152), and C (amino acids 208 to 221) of VP7 revealed that a substitution at position 96 (Asp3Asn) correlated with the change in ability to serotype these G2 strains.Rotaviruses are triple-layered particles of the Reoviridae family that contain 11 segments of double-stranded RNA. The outer layer is composed of VP7 and VP4 proteins, encoded by gene segments 9, 7, or 8 (depending on the strain) and 4, respectively (8). These two proteins elicit neutralizing antibody responses and form the basis for the dual classification system of rotaviruses into G and P types, the designations being derived from glycoprotein (VP7) and protease-sensitive protein (VP4), respectively (8). Comparative sequence analyses of the deduced VP7 amino acid sequences of different animal and human rotavirus serotypes have identified six serotype-specific variable regions (VR) between amino acids (aa) 39 and 50, aa 87 and 101, aa 120 and 130, aa 143 and 152, aa 208 and 221, and aa 233 and 242, and these have been designated VR4 to VR9 (9, 11). VR5, VR7, and VR8 correspond to the antigenic regions A, B, and C, respectively, which have been confirmed as major rotavirus neutralization sites by mapping of neutralization escape mutants (6,7,16,17).Serotyping using G type-specific monoclonal antibodies (MAbs) has been applied widely in rotavirus epidemiological studies. However, the results of many studies have been incomplete due to the limited availability of MAbs specific for types other than G1 to G4, the relatively low sensitivity of the method due mainly to the requirement of intact virus particles, or to the existence of monotypes or antibody escape mutants within the different G types (2-4). Monotypes within G1, G2, G3, and G4 rotaviruses react with different degrees of affinity against different panels of G-specific MAbs (21) .Previously we reported that rotavirus strains collected in the United Kingdom during the 1995-1996 season and genotyped by reverse transcription-PCR as G2 failed to serotype in enzyme-linked immunosorbent assays (ELISAs) using G2-specific MAbs (13). Complementary DNAs of the VP7 genes of a subset of these strains were partially sequenced and compared to corresponding sequences of a subset of successfully serotyped G2 strains collected during 1990 and 1991 in order to identify amino acid substitutions at the VP7 antigenic sites that may be responsible for the failure to react with different G2-specific MAbs.G-serotyping ELISAs and genotyping reverse transcriptionPCRs were performed as previously described (1, 10, 13) using 10% rotavirus-positive fecal suspensions in balanced salt solution. G-serotyping ELISAs (13) Twenty-one G2 rotavirus strains isolated in the United Kingdom-...

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Sequence analysis of VP1 and VP7 genes suggests occurrence of a reassortant of G2 rotavirus responsible for an epidemic of gastroenteritis.

Cited by 45 publications

References 43 publications

Antigenic and Genetic Characterization of Serotype G2 Human Rotavirus Strains from the African Continent

Antigenic and Genetic Characterization of Serotype G2 Human Rotavirus Strains from the African Continent

Molecular Characterization of VP6 Genes of Human Rotavirus Isolates: Correlation of Genogroups with Subgroups and Evidence of Independent Segregation

Amino Acid Substitution within the VP7 Protein of G2 Rotavirus Strains Associated with Failure To Serotype

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