Glycoprotein B of human herpesvirus 8 is a component of the virion in a cleaved form composed of amino- and carboxyl-terminal fragments

Human herpesvirus 8 (HHV-8) or Kaposi's sarcoma-associated herpesvirus (KSH V) is the only known human member of the Rhadinovirus genus of the gammaher pesvirus subfamily. Antibodies against peptides representing portions of th e amino- and carboxyl-termini of HHV-8 gB were produced and used to detect gB expression in Vero cells transfected with the gB gene, in the HHV-8-harb oring cell line, BCBL-1, and in purified virions. Expression of gB was dete cted in approximately 3% of uninduced BCBL-1 cells, while up to 30% of the cells expressed gB after 12-O-tetradecanoylphorbol-13-acetate (TPA) inducti on of virus replication. Indirect immunofluorescence assays and confocal mi croscopy showed that gB was distributed throughout the cytoplasm of BCBL-1 cells and transfected Vero cells. Immunoblot analyses of virion preparation s revealed the presence of full-length as well as two smaller than full-len gth gB-derived species corresponding to the amino- and carboxy-terminal por tions of gB, respectively. Biochemical analysis of the gB carbohydrate moie ties using glycosylation inhibitors revealed that gB contained N-linked oli gosacharides of the high-mannose type, characteristic of precursor carbohyd rate chains added in the endoplasmic reticulum. (C) 2000 Academic Press.