A baculovirus encoded 16-kDa glycoprotein localizes near the nuclear membrane of infected cells.

An open reading frame (ORF 2) located upstream of the polyhedron envelope protein gene of Orgyia pseudotsugata multicapsid nuclear polyhedrosis virus (OpMNPV) was cloned in frame into a trpE expression vector. The fusion protein produced by this construct was used for the production of a monospecific antiserum. Western blot analysis of OpMNPV-infected Lymantria dispar cells detected a 16-kDa protein at 24 hr postinfection. The 16-kDa protein was determined to be N-glycosylated by tunicamycin treatment of infected cells. Immunofluorescence microscopy localized the 16-kDa protein to foci of intense cytoplasmic staining near the nuclear membrane. Immunoelectron microscopy indicated that the 16-kDa protein is associated with lamellar-like structures peripheral to the nuclear membrane and with envelopes of virus that have budded into the cytoplasm. The 16-kDa protein was not associated with extracellular budded or polyhedron-derived virions.