IDENTIFICATION AND ANALYSIS OF AN AUTOGRAPHA-CALIFORNICA NUCLEAR POLYHEDROSIS-VIRUS STRUCTURAL PROTEIN OF THE OCCLUSION-DERIVED VIRUS ENVELOPE - ODV-E56

An Autographa californica nuclear polyhedrosis virus gene encoding an occlusion-derived virus (ODV) envelope protein of 56 kDa was identifie d and sequenced. Transcription initiates from a conserved baculovirus late motif (ATAAG) with transcripts detected from 16 through 72 hr p.i . The protein is detected in infected cell extracts from 36 hr p.i. We stern blot assay of ODV, BV, viral envelope, and nucleocapsid preparat ions coupled with immunoelectron microscopy reveal that this protein l ocalizes to the ODV envelope. This protein is named ODV-E56 to identif y its viral origin, envelope location, and apparent molecular weight. ODV-E56 is enriched in viral induced intranuclear microvesicles as det ermined by immunogold labeling. A mutant was constructed with the C-te rminal portion of the protein replaced with beta-galactosidase. The fu sion protein, E56-beta-gal, locates to the viral nucleocapsids and not to the ODV envelope or intranuclear microvesicles. This suggests that the signals necessary for transport and/or retention into these struc tures lies within the C-terminal portion of ODV-E56. Additionally, bot h ODV-E56 and E56-beta-gal are enriched in electron dense regions that cluster around the inner nuclear membrane and within the nucleoplasm. (C) 1996 Academic Press, Inc.