FIG 6.

GR and KLF15 cooperate to transactivate certain BoHV-1 intergenic regions. Neuro-2A cells were cotransfected with the designated plasmid constructs (0.25 μg of DNA) containing the firefly luciferase gene downstream, a plasmid encoding Renilla luciferase (0.05 μg of DNA), KLF15 (A) or KLF4 (B) (0.5 μg of DNA), and the GR expression plasmid (1 μg of DNA). To maintain equal plasmid amounts in the transfection mixtures, the empty expression vector was added as needed. For these studies, Neuro-2A cells were cultured in 2% stripped fetal calf serum after transfection. Twenty-four hours after transfection the designated Neuro-2A cultures were treated with water-soluble DEX (10 μM; Sigma). At 48 h after transfection, cells were harvested, and protein extracts were subjected to a dual-luciferase assay as described in the Materials and Methods section. The results are the average of three independent experiments, and error bars denote the standard errors. An asterisk denotes a significant difference (P < 0.05) between the value for the empty control (pGL3-promoter vector), as determined by the Student t test. It should be noted that for UL52 the transactivation levels obtained with KLF4 plus GR were not significantly different when DEX was added.