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Strachan M, Mashapa T, Gildenhuys S. Spectroscopic analysis of the bacterially expressed head domain of rotavirus VP6. Biosci Rep 2024; 44:BSR20232178. [PMID: 38592735 PMCID: PMC11065646 DOI: 10.1042/bsr20232178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 04/03/2024] [Accepted: 04/09/2024] [Indexed: 04/10/2024] Open
Abstract
The rotavirus capsid protein VP6 forms the middle of three protein layers and is responsible for many critical steps in the viral life cycle. VP6 as a structural protein can be used in various applications including as a subunit vaccine component. The head domain of VP6 (VP6H) contains key sequences that allow the protein to trimerize and that represent epitopes that are recognized by human antibodies in the viral particle. The domain is rich in β-sheet secondary structures. Here, VP6H was solubilised from bacterial inclusion bodies and purified using a single affinity chromatography step. Spectral (far-UV circular dichroism and intrinsic tryptophan fluorescence) analysis revealed that the purified domain had native-like secondary and tertiary structures. The domain could maintain structure up to 44°C during thermal denaturation following which structural changes result in an intermediate forming and finally irreversible aggregation and denaturation. The chemical denaturation with urea and guanidinium hydrochloride produces intermediates that represent a loss in the cooperativity. The VP6H domain is stable and can fold to produce its native structure in the absence of the VP6 base domain but cannot be defined as an independent folding unit.
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Affiliation(s)
- Milaan Simone Strachan
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida, Roodepoort 1710, South Africa
| | - Tshepo Mashapa
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida, Roodepoort 1710, South Africa
| | - Samantha Gildenhuys
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida, Roodepoort 1710, South Africa
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Doan YH, Suzuki Y, Fujii Y, Haga K, Fujimoto A, Takai-Todaka R, Someya Y, Nayak MK, Mukherjee A, Imamura D, Shinoda S, Chawla-Sarkar M, Katayama K. Complex reassortment events of unusual G9P[4] rotavirus strains in India between 2011 and 2013. INFECTION GENETICS AND EVOLUTION 2017; 54:417-428. [PMID: 28750901 DOI: 10.1016/j.meegid.2017.07.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 11/16/2022]
Abstract
Rotavirus A (RVA) is the predominant etiological agent of acute gastroenteritis in young children worldwide. Recently, unusual G9P[4] rotavirus strains emerged with high prevalence in many countries. Such intergenogroup reassortant strains highlight the ongoing spread of unusual rotavirus strains throughout Asia. This study was undertaken to determine the whole genome of eleven unusual G9P[4] strains detected in India during 2011-2013, and to compare them with other human and animal global RVAs to understand the exact origin of unusual G9P[4] circulating in India and other countries worldwide. Of these 11 RVAs, four G9P[4] strains were double-reassortants with the G9-VP7 and E6-NSP4 genes on a DS-1-like genetic backbone (G9-P[4]-I2-R2-C2-M2-A2-N2-T2-E6-H2). The other strains showed a complex genetic constellation, likely derived from triple reassortment event with the G9-VP7, N1-NSP2 and E6-NSP4 on a DS-1-like genetic backbone (G9-P[4]-I2-R2-C2-M2-A2-N1-T2-E6-H2). Presumably, these unusual G9P[4] strains were generated after several reassortment events between the contemporary co-circulating human rotavirus strains. Moreover, the point mutation S291L at the interaction site between inner and outer capsid proteins of VP6 gene may be important in the rapid spread of this unusual strain. The complex reassortment events within the G9[4] strains may be related to the high prevalence of mixed infections in India as reported in this study and other previous studies.
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Affiliation(s)
- Yen Hai Doan
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan; Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Graduate School of Infection Control Sciences, Japan
| | - Yoshiyuki Suzuki
- Graduate School of Natural Sciences, Nagoya City University, Nagoya, Aichi, Japan
| | - Yoshiki Fujii
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kei Haga
- Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Graduate School of Infection Control Sciences, Japan
| | - Akira Fujimoto
- Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Graduate School of Infection Control Sciences, Japan
| | - Reiko Takai-Todaka
- Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Graduate School of Infection Control Sciences, Japan
| | - Yuichi Someya
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Mukti K Nayak
- Division of Virology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Anupam Mukherjee
- Division of Virology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Daisuke Imamura
- Collaborative Research Center of Okayama University for Infectious Diseases, India
| | - Sumio Shinoda
- Collaborative Research Center of Okayama University for Infectious Diseases, India
| | - Mamta Chawla-Sarkar
- Division of Virology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Kazuhiko Katayama
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan; Laboratory of Viral Infection I, Kitasato Institute for Life Sciences, Graduate School of Infection Control Sciences, Japan.
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Yuan J, Zhang X, Shi H, Chen J, Han X, Wei P, Feng L. The interaction of Rotavirus A pig/China/NMTL/2008/G9P[23] VP6 with cellular beta-actin is required for optimal RV replication and infectivity. Vet Microbiol 2016; 197:111-121. [PMID: 27938672 DOI: 10.1016/j.vetmic.2016.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 10/22/2016] [Accepted: 11/09/2016] [Indexed: 11/16/2022]
Abstract
VP6 forms the intermediate layer of the rotavirus (RV) capsid, and it plays important roles after RV penetration and uncoating. These functions rely on its ability to interact with host cell proteins. To gain further insights into the role of VP6 in porcine RV (PoRV) infection, a glutathione S-transferase pull-down assay was utilized to find unknown cellular factors that interact with VP6. In this study, beta-actin, tropomyosin 1, and 40S ribosomal protein S16 were identified as interaction partners of VP6 by mass spectrometry and co-immunoprecipitation. The interaction with beta-actin was further studied. By immunoelectron microscopy, we observed VP6 proteins that labeled with colloidal gold localized on the actin microfilaments at the early stage of PoRV infection, we also found VP6 distributed in the ribosome, mitochondria, endoplasmic reticulum and nucleus in the infected cells. Actin binding protein spin-down assays verified PoRV double-layered particles (DLPs) bound to F-actin in vitro, but didn't have actin polymerization enhancement activity. After a small interfering RNA (siACTB) was used to knock down beta-actin expression, PoRV VP6 expression and the infection rates of newly synthesized virions releasing into culture supernatants decreased dramatically. Our results confirm and extend previous reports indicating that the interaction between PoRV VP6 and beta-actin plays vital roles in the PoRV lifecycle.
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Affiliation(s)
- Jing Yuan
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China; Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Xin Zhang
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Hongyan Shi
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Jianfei Chen
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Xiao Han
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Ping Wei
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China.
| | - Li Feng
- Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China.
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Corthésy B, Benureau Y, Perrier C, Fourgeux C, Parez N, Greenberg H, Schwartz-Cornil I. Rotavirus anti-VP6 secretory immunoglobulin A contributes to protection via intracellular neutralization but not via immune exclusion. J Virol 2006; 80:10692-9. [PMID: 16956954 PMCID: PMC1641769 DOI: 10.1128/jvi.00927-06] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Immunoglobulin A (IgA) monoclonal antibodies (MAbs) directed at the conserved inner core protein VP6 of rotavirus, such as the IgA7D9 MAb, provide protective immunity in adult and suckling mice when delivered systemically. While these antibodies do not have traditional in vitro neutralizing activity, they could mediate their antiviral activity either by interfering with the viral replication cycle along the IgA secretory pathway or by acting at mucosal surfaces as secretory IgA and excluding virus from target enterocytes. We sought to determine the critical step at which antirotaviral activity was initiated by the IgA7D9 MAb. The IgA7D9 MAb appeared to directly interact with purified triple-layer viral particles, as shown by immunoprecipitation and immunoblotting. However, protection was not conferred by passively feeding mice with the secretory IgA7D9 MAb. This indicates that the secretory IgA7D9 MAb does not confer protection by supplying immune exclusion activity in vivo. We next evaluated the capacity of polymeric IgA7D9 MAb to neutralize rotavirus intracellularly during transcytosis. We found that when polymeric IgA7D9 MAb was applied to the basolateral pole of polarized Caco-2 intestinal cells, it significantly reduced viral replication and prevented the loss of barrier function induced by apical exposure of the cell monolayer to rotavirus, supporting the conclusion that the antibody carries out its antiviral activity intracellularly. These findings identify a mechanism whereby the well-conserved immunodominant VP6 protein can function as a target for heterotypic antibodies and protective immunity.
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Affiliation(s)
- Blaise Corthésy
- R & D Laboratory of the Division of Immunology and Allergy, DMI-CHUV, Rue du Bugnon, 1011 Lausanne, Switzerland
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Greig SL, Berriman JA, O'Brien JA, Taylor JA, Bellamy AR, Yeager MJ, Mitra AK. Structural determinants of rotavirus subgroup specificity mapped by cryo-electron microscopy. J Mol Biol 2005; 356:209-21. [PMID: 16359700 DOI: 10.1016/j.jmb.2005.11.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 11/10/2005] [Accepted: 11/15/2005] [Indexed: 11/30/2022]
Abstract
The rotavirus double-layered particle (DLP) is a molecular machine that transcribes 11 genomic segments of double-stranded RNA into full-length mRNA segments during viral replication. DLPs from the human Wa strain of virus, belonging to subgroup II (SG II), possess a significantly reduced level of transcriptase activity compared to bovine UK DLPs that belong to subgroup I (SG I). Cryo-electron microscopy and icosahedral image analysis was used to define the structural basis for this difference in transcriptase activity and to derive three-dimensional density maps of bovine UK and human Wa DLPs at 26 angstroms and 28 angstroms resolution, respectively. The two rotavirus strains had the same diameter, T = 13 l icosahedral lattice symmetry and size of the VP6 trimers on the surface of the DLPs. However, the Wa particles displayed a remarkable absence of VP6 trimers surrounding each 5-fold vertex position. To further explore these structural differences, three-dimensional reconstructions were generated of DLPs decorated with Fab fragments derived from subgroup-specific monoclonal antibodies. The X-ray structures of VP6 and a generic Fab fragment were then docked into the cryo-electron microscopy density maps, which allowed us to propose at "pseudo-atomic" resolution the locations of the amino acid residues defining the subgroup-specific epitopes. Our results demonstrate a correlation between the structure of the VP6 layer and the transcriptase activity of the particles, and suggest that the stability of VP6 trimers, specifically those at the icosahedral 5-fold axes, may be critical for mRNA synthesis. Thus, subgroup specificity of rotavirus may reflect differences in the architecture of the double-layered particle, with resultant consequences for viral mRNA synthesis.
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Affiliation(s)
- Sarah L Greig
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Schwartz-Cornil I, Benureau Y, Greenberg H, Hendrickson BA, Cohen J. Heterologous protection induced by the inner capsid proteins of rotavirus requires transcytosis of mucosal immunoglobulins. J Virol 2002; 76:8110-7. [PMID: 12134016 PMCID: PMC155125 DOI: 10.1128/jvi.76.16.8110-8117.2002] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protective immunization against rotavirus (RV) can be achieved with heterologous RV, i.e., virus isolated from another species, and with heterologous inner core VP2 and VP6 proteins assembled as virus-like particles (VLP). Although the antigenically conserved VP6 protein does not induce in vitro-neutralizing antibodies, it may, however, elicit immunoglobulins (Ig) involved in heterologous protection, as some IgA against VP6 prevent RV infection in a backpack mouse model. The protective role of Ig directed to the RV inner core proteins VP2 and VP6 was investigated in J-chain-deficient mice (J chain(-/-)), which have a defect in the polymeric Ig receptor (pIgR)-mediated transcytosis of IgA and IgM. J chain(-/-) mice and wild-type (WT) mice were intranasally vaccinated with bovine RV-derived VLP2/6 and then challenged with highly infectious murine ECw RV. Whereas WT mice were totally protected, immunized J chain(-/-) mice shed RV for several days. In addition, naïve J chain(-/-) mice exhibited a 2-day delay in clearing RV compared with WT mice. The immunized J chain(-/-) mice displayed unaltered VLP2/6-specific B-cell numbers in spleen and in mesenteric nodes and similar levels of serum anti-VLP2/6 Ig, confirming that the adaptive B-cell response is preserved in J chain(-/-) mice. These results indicate that J-chain-mediated transcytosis of Ig participates in the clearance of RV and that epithelial pIgR-mediated transport of Ig is involved in the heterologous protection induced by VLP2/6.
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