There are currently 4 major areas of research in the laboratory, all involving herpes simplex virus. The first area is concerned with the structure of replicating viral DNA. Our goal is to understand more fully the mechanism whereby the large genome (10 to the 8th power mol.wt.) is replicated. These studies are being pursued in infected cells as well as in an in vitro system, developed in the lab. The second area concerns the modification of viral DNA prior to its involvement in transcription and replication, and the processing and encapsidation of progeny viral DNA. These studies are utilizing micrococcal nuclease sensitivity of viral DNA as a measure of the association of viral DNA with virus specified structural (virion) and non-structural proteins. The third area is concerned with the mechanism whereby the virus shuts off host protein synthesis and regulates its own temporal program of protein synthesis. Analyses of polysome associated mRNA populations in reticulocyte lysates is the major analytical tool in these studies. The fourth involves the study of viral specific transcription. We are taking two approaches in this regard: the first is to develop or adapt nuclear monolayer or totally cell free in vitro systems for analyzing the requirements for transcription initiation at specific (presumably correct) promoter sites. The second approach is to clone small fragments of viral DNA into plasmid vectors, screen them for transcription initiation sites in the cell-free system mentioned above and begin comparative nucleotide sequencing studies within and between groups of coordinately controlled promoters.