BIOSYNTHESIS AND LOCALIZATION OF THE AUTOGRAPHA-CALIFORNICA NUCLEAR POLYHEDROSIS-VIRUS 25K GENE-PRODUCT

Mutations of the AcMNPV 25K gene are associated with the ''few polyhed ra'' phenotype (M. J. Fraser at al., 1983, J. Virol. 47, 287-300; B. B eames and M. D. Summers, 1989, Virology 168, 344-353). Polyclonal anti sera was produced and used to investigate the time course of expressio n and localization of the 25K protein in infected cells. Western blot analysis detected 25K protein in both cytosolic and nuclear extracts f rom 18-24 hr p.i. through 96 hr p.i. and also in purified viral occlus ions, but not in purified virions. Immunogold electron microscopy reve aled that 25K protein was predominantly associated with amorphous cyto plasmic structures and to a lesser extent with a more electron-dense s tructure in the nucleus. Viral occlusions in cell sections were not sp ecifically labeled by 25K antibody. Observations of purified viral occ lusions and nuclei prepared for immunogold EM revealed the presence of contaminating amorphous material that was labeled with 25K antibody. (C) 1995 Academic Press, Inc.