Nuclear assembly of polyomavirus capsids in insect cells expressing the major capsid protein VP1.

摘要: Polyomavirus normally assembles in the nucleus of infected mouse cells. Sf9 insect cells expressing polyomavirus major capsid protein VP1 were examined by electron microscopy. Capsidlike particles apparently uniform size found nucleus. Immunogold microscopy demonstrated abundant cytoplasm which was not assembled into any recognizable higher-order structure. Cytoplasmic after treated with calcium ionophore ionomycin. Purified aggregates shown negative staining and cryoelectron to consist predominantly similar empty T = 7 viral capsid. Thus, can assemble vivo capsids independent other proteins or DNA. Nuclear assembly may result from increased available this subcellular compartment.