9-beta-D-Arabinofuranosyladenine as a tool to study herpes simplex virus DNA replication in vitro.

9-β-d-Arabinofuranosyladenine (araAdo) strongly suppresses herpes simplex virus (HSV) DNA synthesis in intact cell systems. After incubation with araAdo, two HSV-DNA fractions can be isolated by neutral isopycnic CsCl density gradient centrifugation, a light fraction with a buoyant density of 1.726 g/cm³, and a heavy fraction with a density of 1.738 g/cm³. After recentrifugation in neutral CsCl gradients, the light and heavy fractions are detected at a density of 1.729 and 1.741, respectively. Analysis of the two HSV-DNA fractions by hydroxylapatite chromatography and by digestion with nuclease S₁ revealed that the light fraction consists predominantly of native DNA and the heavy fraction of denatured DNA. AraAdo is incorporated into HSV-DNA and has been shown to be present in terminal positions at the 3′-hydroxyl position. The HSV-DNA pieces, containing incorporated araAdo, are of low molecular weight (less than 2.6 × 10⁶) and are not assembled to higher molecular weight aggregates.