Autographa californicaNuclear Polyhedrosis Virus: Subcellular Localization and Protein Trafficking of BV/ODV-E26 to Intranuclear Membranes and Viral Envelopes

Abstract

The Autographa californica nuclear polyhedrosis virus da26 gene codes for an envelope protein of both budded virus (BV) and occlusion derived virus (ODV). Western blot and temporal analysis of infected cell extracts detected a protein of 26 kDa by 4 h postinfection (p.i.). The amount of protein increased by 16 h p.i. and remained at high levels throughout infection. By 36 h p.i. several additional immunoreactive proteins were detected which migrated at approximately 18 kDa and remained through 96 h p.i. Western blot analysis of purified virus envelope and nucleocapsid preparations revealed that both the 26- and 18-kDa proteins are structural proteins of the envelope of BV and ODV. Immunoelectron microscopy performed at a time when only the 26-kDa species of the protein was present confirmed that the protein located to ODV envelope. The protein was named BV/ODV-E26 to designate incorporation into viral progeny, envelope location, and apparent molecular weight. Studies designed to follow localization of BV/ODV-E26 demonstrated that early in infection, the protein was incorporated into cytoplasmic vesicles and by 16 h p.i., BV/ODV-E26 was detected in the nucleus associated with virus-induced intranuclear microvesicles and ODV envelope. Coimmunoprecipitation and yeast two-hybrid assays showed that BV/ODV-E26 and FP25K were capable of interacting with each other to form a complex and coimmunoprecipitation assays indicated that cellular actin was a third component of this complex. Together, these data suggest that FP25K and cellular actin may participate in the regulation, or movement through the cell, of baculovirus proteins and/or virus nucleocapsids.

Autographa californica Multiple Nucleopolyhedrovirus orf132 Encodes a Nucleocapsid-Associated Protein Required for Budded-Virus and Multiply Enveloped Occlusion-Derived Virus Production

“…Immunoconfocal microscopy revealed that AC132 formed a ring zone in the periphery of the nucleus in infected cells, which is similar to the intranuclear localization of AcMNPV E25, E26, AC76, AC92, and AC109 (34,47,48,(57)(58)(59)(60)(61). E25, E26, and AC76 are associated with virus-induced microvesicles in the nucleus (57)(58)(59).…”

Trafficking of ODV-E66 is mediated via a sorting motif and other viral proteins: Facilitated trafficking to the inner nuclear membrane

“…Because FP25K has already been implicated in the trafficking of E66 (7,13), its identification here poses the possibility that it directly interacts with E66. The function of FP25K and E26 are undetermined; however, it has been speculated that they interact with actin and͞or cytoplasmic dynein (14).…”

Sequence analysis of the genome of Bombyx mori nucleopolyhedrovirus.

“…The locations of BmNPV homologous regions (hr) are also indicated. Names of ORFs were taken from Possee & Rohrmann (1997), Beniya et al (1998), Roncarati & KnebelMorsdorf (1997), McLachlin & Miller (1997), Olszewski & Miller (1997) or Rapp et al (1998) or the references listed (see footnote). The position of each ORF defines the A of the initiation codon (ATG) and the T of the termination codon (TAA\TAG\TGA) of its encoding strand.…”