Metabolic fate of [3H]1-beta-D-arabinofuranosyl-5-[(E)-2-bromovinyl]uracil in herpes simplex virus type 1-infected cells.

Abstract

The metabolic fate of 1-beta-D-arabinofuranosyl-5-[(E)-2-bromovinyl]uracil (BV-araU) in herpes simplex virus type 1-infected cells was studied using tritium-labeled BV-araU. [3H]BV-araU was selectively taken-up by infected cells. Approximately 10% of the total uptake of [3H]BV-araU was recovered from the acid-insoluble fraction at any time post-infection. Both cellular uptake of [3H]BV-araU and its incorporation into the acid-insoluble fraction increased with increasing incubation time through 8 hr post-infection. Uptake of [3H]BV-araU and its incorporation into the acid-insoluble fraction also increased proportionally to the duration of exposure to [3H]BV-araU. An alkaline sucrose gradient sedimentation analysis revealed that the radioactive DNA obtained from cells pulse-labeled with [3H]BV-araU were small DNA fragments which remained at the top following a chasing period in isotope-free medium, whereas that pulse-labeled with [3H]thymidine was chased to a fraction of high molecular weight DNA. Nuclease P1 digestion reduced 99% of the [3H]BV-araU-labeled DNA extracted from infected cells to a low molecular weight. Following digestion of [3H]BV-araU-labeled DNA with micrococcal nuclease and spleen exonuclease, all of the radioactivity was recovered as [3H]BV-araU 3'-monophosphate. Thus, BV-araU strongly inhibits the elongation of viral DNA strands as demonstrated by the alkaline sucrose gradient sedimentation analysis, whereas at least a portion of the [3H]BV-araU is incorporated inside viral DNA strands in infected cells.