Enhancement of herpes simplex virus type 2 (HSV-2) DNA synthesis in infected cells that constitutively express the BglII-N region of the HSV-2 genome.

The BglII-N fragment of the herpes simplex virus type-2 (HSV-2) genome encodes one of two known transforming regions of this DNA virus. In this study, we report the derivation of HeLa S3 cells (2DC4) that stably express the HSV-2 BglII-N region, including the small subunit of HSV-2 ribonucleotide reductase (RR). Superinfection of the 2DC4 cells with wild-type HSV-2 resulted in the efficient induction of HSV-2-encoded ICP10, DNA polymerase, and thymidine kinase. The amount of HSV-2 DNA synthesis in 8-hr HSV-2-infected 2DC4 cells was enhanced 2.6 +/- 0.6-fold relative to infected control cells. Furthermore, the replication kinetics of HSV-2 DNA in 2DC4 cells were accelerated relative to HeLa S3 cells; HSV-2 DNA synthesis was detectable as early as 3 hr postinfection in 2DC4 cells as compared to 6 hr postinfection in HeLa S3 cells. These results suggest that the BglII-N region of HSV-2 encodes function(s) that activate the viral DNA synthesis apparatus and that this activation could relate to the transforming ability of this DNA region.