Cellular Egr-1 and virus-encoded KSHV RTA follow a similar expression pattern during de novo KSHV infection Several different viruses are known to activate Egr-1 expression upon infection [17, 18, 19, 20] . Since BCBL-1 cells already carry KSHV DNA, KSHV-infected HEK293 cells were used to evaluate the expression pattern of Egr-1 and KSHV RTA during early stages of de novo infection. Expression of Egr-1 and RTA proteins were significantly elevated by 1 hour post infection (hPI) and continued to maintain increased expression until roughly 6-8 hPI (Fig. 3A, lanes 2-4) . In contrast, a considerable decrease in the expression of these proteins was observed from 12-48 hPI (Fig. 3A , lanes 5-7). A significant difference in expression of total bactin was not observed (Fig. 3A ) during the course of KSHV infection demonstrating the specificity of the results on Egr-1 and RTA expression.