IMMUNOELECTRON MICROSCOPIC LOCALIZATION OF HERPES-SIMPLEX VIRUS GLYCOPROTEIN GB IN THE NUCLEAR-ENVELOPE OF INFECTED-CELLS

Herpesviruses, such as herpes simplex type 1 (HSV-1) acquire their env elope by budding through a modified inner membrane of the nuclear enve lope which forms thick and dense patches at the site of budding. This suggests that some of the viral envelope glycoproteins must be transpo rted to the nuclear envelope in order to be incorporated into the viru s. In an effort to establish the localization of the HSV-1 glycoprotei n gB-1 in the nuclear envelope of HSV-1 infected cells directly, we ha ve studied the distribution of the glycoprotein gB-1 by immunoelectron microscopy using a polyclonal anti gB-1 antibody. A specific accumula tion of gB-1 in the nuclear envelope, which was five times more labele d than the plasma membrane was observed. The glycoprotein gB-1 was loc alized in both the outer and the inner membrane of the nuclear envelop e. The labeling over the nuclear envelope was distributed evenly and n o preferential concentration of gB-1 around or within the patches wher e the virus buds was detected. The nucleocapsids were found to be labe led only when they become associated with the nuclear envelope indicat ing that gB-1 is incorporated into the virus at this site.