PREEXISTING NUCLEAR ARCHITECTURE DEFINES THE INTRANUCLEAR LOCATION OFHERPESVIRUS DNA-REPLICATION STRUCTURES

Herpes simplex virus DNA replication proteins localize in characterist ic patterns corresponding to viral DNA replication structures in the i nfected cell nucleus. The intranuclear spatial organization of the HSV DNA replication structures and the factors regulating their nuclear l ocation remain to be defined. We have used the HSV ICP8 DNA-binding pr otein and bromodeoxyuridine labeling as markers for sites of herpesvir al DNA synthesis to examine the spatial organization of these structur es within the cell nucleus. Confocal microscopy and three-dimensional computer graphics reconstruction of optical series through infected ce lls indicated that viral DNA replication structures extend through the interior of the cell nucleus and appear to be spatially separate from the nuclear lamina. Examination of viral DNA replication structures i n infected, binucleate cells showed similar or virtually identical pat terns of DNA replication structures oriented along a twofold axis of s ymmetry between many of the sister nuclei. These results demonstrate t hat HSV DNA replication structures are organized in the interior of th e nucleus and that their location is defined by preexisting host cell nuclear architecture, probably the internal nuclear matrix.