Transient Assays for HSV Origin and Replication Protein Function

Investigations of genome replication in DNA viruses involve several facets. These include characterizing the sites at which synthesis is initiated (origins of DNA replication), identifying the viral and host proteins that participate, understanding the enzymatic activities of these proteins, and elucidating the mechanisms of DNA synthesis and maturation. For several viruses cell-free systems capable of carrying out faithful viral origin-dependent DNA synthesis have been described that have provided important insights into these areas. Unfortunately, such an assay is not yet available for HSV and other approaches therefore have been required. One of the most useful and widely employed has involved transient assays for viral origin-dependent DNA synthesis in transfected tissue culture cells. Such assays played important roles in the initial identification of the viral replication origins and the virus-coded proteins essential for DNA synthesis and more recently have helped provide detailed information on the structure and function of these elements. Similar approaches also have been exploited to study genome replication in other herpesviruses.