The major capsid protein of human polyomavirus JC virus, VP1, has been cloned into a baculovirus genome and expressed in insect cells. The VP1 protein was expressed in the cytoplasm and transported into the nucleus. It was then purified by a sucrose cushion and CsCl density gradient centrifugation to near homogeneity. Electron microscopy showed that isolated recombinant VP1 protein self-assembled into a capsid-like structure similar to the natural empty capsid. Both chelator (EDTA) and reducing agent (DTT) are required to disrupt the capsid structure into the pentameric capsomeres, as demonstrated by haemagglutination assay and electron microscopy. These results suggest that JC virus VP1 can be transported into the nucleus and self-assembled to form capsid-like particles without the involvement of the viral minor capsid proteins, VP2 and VP3. In addition, metal ions and disulphide bonds appear to be important in maintaining the integrity of the viral capsid structure.
BolenJ. B.,
AndersD. G.,
TrempyJ.,
ConsigliR. A.1981; Differences in the subpopulations of the structural proteins of polyoma virions and capsids : biological functions of the multiple VP1 species. Journal of Virology 37:80–91
BradyJ. N.,
WinstonV. D.,
ConsigliR. A.1977; Dissociation of polyomavirus by the chelation of calcium ions found associated with purified virions. Journal of Virology 23:717–724
ChangD.,
HaynesJ. I.,
BradyJ. N.,
ConsigliR. A.1992; The use of additive and subtractive approaches to examine the nuclear localization sequence of the polyomavirus major capsid protein VP1. Virology 189:821–827
ChristiansenG.,
LanderT. O.,
GriffithJ.,
BergP. O.1977; Characterization of components released by alkali disruption of simian virus 40. Journal of Virology 21:1079–1084
DysonN.,
BernardsR.,
FriendS. H.,
GoodingL. R.,
HassellJ. A.,
MajorE. O.,
PipasJ. M.,
VandykeT.,
HarlowE.1990; Large T antigens of many polyomaviruses are able to form complexes with the retinoblastoma protein. Journal of Virology 64:1353–1356
FeigenbaumL.,
KhaliliK.,
MajorE. O.,
KhouryG.1987; Regulation of the host range of human papovavirus JCV. Proceedings of the National Academy of Sciences, USA 84:3695–3698
ForstovaJ.,
KrauzewiczN.,
WallaceS.,
StreetA. J.,
DilworthS. M.,
BeardS.,
GriffinB. E.1993; Cooperation of structural proteins during late events in the life cycle of polyomavirus. Journal of Virology 67:1405–1413
HaynesJ. I.IIChangD.,
ConsigliR. A.1993; Mutations in the putative calcium-binding domain of polyomavirus VP1 affect capsid assembly. Journal of Virology 67:2486–2495
IshiiN.,
MinamiN.,
ChenE.,
MedinaA. L.,
ChicoM. M.,
KasamatsuH.1996; Analysis of a nuclear localization signal of simian virus 40 major capsid protein VP1. Journal of Virology 70:1317–1322
MandlC.,
WalkerD. L.,
FrisqueR. J.1987; Derivation and characterization of POJ cells, transformed human fetal glial cells that retain their permissivity for JC virus. Journal of Virology 61:755–763
MontrossL.,
WatkinsS.,
MorelandR. B.,
MamonH.,
CasparD. L. D.,
GarceaR. L.1991; Nuclear assembly of polyomavirus capsids in insect cells expressing the major capsid protein VP1. Journal of Virology 65:4991–4998
PadgettB. L.,
WalkerD. L.,
Zu RheinG. M.,
HodachA. E.,
ChowS. M.1976; JC papovavirus in progressive multifocal leukoencephalopathy. Journal of Infectious Disease 133:686–690
WalkerD. L.,
FrisqueR. J.1986; The biology and molecular biology of JC virus. In The Papovaviridae pp. 327–377SalzmanN. P.
Edited by New York: Plenum Press;
WhiteF. A.IIIIshaqM.,
StonerG. L.,
FrisqueR. J.1992; JC virus DNA is present in many human brain samples from patients without progressive multifocal leukoencephalopathy. Journal of Virology 66:5726–5734
Zu RheinG. M.1983; Studies of JC virus-induced nervous system tumors in the Syrian hamster : a review. In Polyomaviruses and Human Neurological Diseases pp. 205–221SeverJ. L.,
MaddenD. L.
Edited by New York: Alan R. Liss;