CHARACTERIZATION OF A HIGHLY CONSERVED BACULOVIRUS STRUCTURAL PROTEINTHAT IS SPECIFIC FOR OCCLUSION-DERIVED VIRIONS

A highly conserved baculovirus late gene called odvp-6e was shown to b e a structural protein that is specific for occlusion-derived virus (O DV) envelopes. The complete sequence of this gene is presented for bot h Orgyia pseudotsugata nuclear polyhedrosis virus (OpMNPV) and Cydia p omonella granulosis virus (CpGV). The predicted sizes of the OpMNPV an d CpGV ODVP-6E are 40, 241, and 38,655 respectively. The OpMNPV odvp-6 e gene was transcriptionally mapped and was shown to initiate from a c onsensus late gene motif, TTAAG, and is expressed from 18-120 hr posti nfection. Polyclonal antiserum was generated against a bacterial fusio n protein and used to analyze the cellular steady-state levels of ODVP -6E and to determine if this protein was a component of either budded virus (BV) or ODV. Western blots showed that ODVP-6E is a component of the ODV but not BV. This was confirmed by immunoelectron microscopy o f ODV from Autographa californica NPV (AcMNPV) which localized ODVP-6E to the ODV envelope. The sequences of the odvp-6e gene from the bacul oviruses Choristoneura fumiferana NPV (CfMNPV), AcMNPV, and Helicoverp a tea NPV (HzSNPV) were obtained from GenBank. Comparisons of the pred icted amino acid sequences of OpMNPV, CpGV, AcMNPV, CfMNPV, and HzSNPV show that there are two possible membrane-spanning domains and a cyst eine-rich domain that are conserved in all of the proteins. (C) 1996 A cademic Press, Inc.