title: Molecular and structural characterization of fluorescent human parvovirus B19 virus-like particles.
abstract: Although sharing a T=1 icosahedral symmetry with other members of the Parvoviridae family, it has been suggested that the fivefold channel of the human parvovirus B19 VP2 capsids is closed at its outside end. To investigate the possibility of placing a relatively large protein moiety at this site of B19, fluorescent virus-like particles (fVLPs) of B19 were developed. The enhanced green fluorescent protein (EGFP) was inserted at the N-terminus of the structural protein VP2 and assembly of fVLPs from this fusion protein was obtained. Electron microscopy revealed that these fluorescent protein complexes were very similar in size when compared to wild-type B19 virus. Further, fluorescence correlation spectroscopy showed that an average of nine EGFP domains were associated with these virus-like structures. Atomic force microscopy and immunoprecipitation studies showed that EGFP was displayed on the surface of these fVLPs. Confocal imaging indicated that these chimeric complexes were targeted to late endosomes when expressed in insect cells. The fVLPs were able to efficiently enter cancer cells and traffic to the nucleus via the microtubulus network. Finally, immunoglobulins present in human parvovirus B19 acute and past-immunity serum samples were able to detect antigenic epitopes present in these fVLPs. In summary, we have developed fluorescent virus-like nanoparticles displaying a large heterologous entity that should be of help to elucidate the mechanisms of infection and pathogenesis of human parvovirus B19. In addition, these B19 nanoparticles serve as a model in the development of targetable vehicles designed for delivery of biomolecules.
authors.affiliation: Department of Biological and Environmental Science, P.O. Box 35, FIN-40014 University of Jyväskylä, Finland.
authors.forename: Leona
authors.initials: L
authors.lastname: Gilbert
authors.forename: Jouni
authors.initials: J
authors.lastname: Toivola
authors.forename: Daniel
authors.initials: D
authors.lastname: White
authors.forename: Teemu
authors.initials: T
authors.lastname: Ihalainen
authors.forename: Wesley
authors.initials: W
authors.lastname: Smith
authors.forename: Laura
authors.initials: L
authors.lastname: Lindholm
authors.forename: Matti
authors.initials: M
authors.lastname: Vuento
authors.forename: Christian
authors.initials: C
authors.lastname: Oker-Blom
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002460:Cell Line; D045744:Cell Line, Tumor; D011992:Endosomes / Q000378:metabolism / Q000821:virology; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D047468:Immunoprecipitation; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure / Q000821:virology; D010322:Parvoviridae Infections / Q000276:immunology; D016732:Parvovirus B19, Human / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D018411:Spodoptera; D014771:Virion / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D019065:Virus Assembly
chemical_list: D036022:Capsid Proteins; D007106:Immune Sera; D011993:Recombinant Fusion Proteins; C095548:capsid protein VP2, parvovirus B19; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins