title: Bovine leukemia virus Gag particle assembly in insect cells: formation of chimeric particles by domain-switched leukemia/lentivirus Gag polyprotein.
abstract: A key stage in the life cycle of C-type retroviruses is the assembly of Gag precursor protein at the plasma membrane of infected cells. Here we report the assembly of bovine leukemia virus (BLV) gag gene product into virus-like particles (VLPs) using the baculovirus expression system. Expression of BLV Pr44(Gag) resulted in the assembly and release of VLPs, thereby confirming the ability of retroviral Gag polyprotein to assemble and bud from insect cells. Efficient particle formation required a myristoylation signal at the N-terminus of BLV Pr44(Gag). Recombinant baculoviruses expressing matrix (MA) or capsid-nucleocapsid (CA-NC) proteins of BLV were generated but neither of these domains was capable of assembling into particulate structures. To assess the compatibility of Gag domains between leukemia and lentivirus groups three different recombinant chimeras each expressing MA of one virus (e.g., simian immunodeficiency or BLV) and CA-NC of another (e.g., BLV or human T-cell leukemia virus type-I) were constructed. Each of the chimeric proteins assembled efficiently and budded as VLPs, suggesting that the MA and CA domains of these two evolutionary divergent retrovirus groups can be functionally exchanged without perturbation of Gag VLP formation. The lenti-leukemia chimeric Gag approach has potential for studying protein-protein interactions in other retroviruses.
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.
authors.forename: N K
authors.initials: NK
authors.lastname: Kakker
authors.forename: M V
authors.initials: MV
authors.lastname: Mikhailov
authors.forename: M V
authors.initials: MV
authors.lastname: Nermut
authors.forename: A
authors.initials: A
authors.lastname: Burny
authors.forename: P
authors.initials: P
authors.lastname: Roy
mesh_terms: D000818:Animals; D002213:Capsid / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics; D006801:Humans; D001909:Leukemia Virus, Bovine / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D009227:Myristic Acids / Q000378:metabolism; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism*; D020815:Polyproteins / Q000235:genetics / Q000378:metabolism; D015302:Simian Immunodeficiency Virus / Q000235:genetics; D018411:Spodoptera / Q000166:cytology; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000648:ultrastructure; D019065:Virus Assembly
chemical_list: D015683:Gene Products, gag; D009227:Myristic Acids; D019590:Nucleocapsid Proteins; D020815:Polyproteins; D014763:Viral Matrix Proteins