VP1, the putative RNA-dependent RNA polymerase of infectious bursal disease virus, forms complexes with the capsid protein VP3, leading to efficient encapsidation into virus-like particles.
A cDNA corresponding to the coding region of VP1, the putative RNA-dependent RNA polymerase, of infectious bursal disease virus (IBDV) was cloned and inserted into the genome of a vaccinia virus inducible expression vector. The molecular mass and antigenic reactivity of VP1 expressed in mammalian cells are identical to those of its counterpart expressed in IBDV-infected cells. The results presented here demonstrate that VP1 is efficiently incorporated into IBDV virus-like particles (VLPs) produced in mammalian cells coexpressing the IBDV polyprotein and VP1. Incorporation of VP1 into VLPs requires neither the presence of IBDV RNAs nor that of the nonstructural polypeptide VP5. Immunofluorescence, confocal laser scanning microscopy, and immunoprecipitation analyses conclusively showed that VP1 forms complexes with the structural polypeptide VP3. Formation of VP1-VP3 complexes is likely to be a key step for the morphogenesis of IBDV particles.
Departments of Biología Molecular y Celular, Centro Nacional de Biotecnología, Cantoblanco, 28049 Madrid, Spain.
E
E
Lombardo
A
A
Maraver
J R
JR
Castón
J
J
Rivera
A
A
Fernández-Arias
A
A
Serrano
J L
JL
Carrascosa
J F
JF
Rodriguez
D000818:Animals; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D002460:Cell Line; D002522:Chlorocebus aethiops; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D007243:Infectious bursal disease virus / Q000201:enzymology* / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions; D015678:Viral Structural Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion; D019065:Virus Assembly
D036022:Capsid Proteins; D011506:Proteins; C107669:VP1 protein, infectious bursal disease virus; C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins; D012324:RNA-Dependent RNA Polymerase