Resveratrol inhibits Egr-1 and ORF50 during early and late stages of infection Due to the vital role of MAPK signaling on Egr-1 expression and KSHV reactivation, the effect of resveratrol on KSHV replication was analyzed. We chose to use resveratrol because: (i) it is a naturally occurring product; and (ii) it is a known regulator of MAPK signaling and Egr-1 expression [14] . Furthermore, resveratrol inhibits ERK1/2 activity in virus-infected cells [23] . It is important to understand that even though KSHV-encoded ORF50 is a gene crucial for reactivation, it is also expressed during early stages of KSHV infection and may play a role in the establishment of virus latency [6, 24] . Therefore, it was necessary to determine the expression pattern of cellular egr-1 and virusencoded ORF50 during both early stages of infection as well as during virus reactivation (late stages). In this study, effect of resveratrol on early stages of infection was analyzed in HEK293 cells while its effect on late stages (reactivation using TPA) was analyzed predominantly in BCBl-1 cells, for convenience. In this study, resveratrol was able to inhibit egr-1 expression in a dose dependent manner during early stages of de novo KSHV infection of HEK293 cells (Fig. 5A) . The doses tested in this study were confirmed by trypan blue test to be non-toxic to cells (data not shown). The resveratrol doses used by us are also those that have been published previously [25, 26, 27] . Resveratrol (100 mM) was able to suppress the expression of phospho-ERK1/2 and Egr-1 proteins during de novo infection of cells (Fig. 5B, lanes 3, 6, and 9 ). Additionally, resveratrol was able to inhibit the expression Egr-1 and phophorylated ERK1/2 in mock-infected cells ( Figure S1,  lanes 2, 4, and 6 ). On the other hand, it was not able to significantly alter the expression of endogenous ERK1/2 and actin controls (Fig. 5B, lanes 3, 6, and 9 ; Figure S1, lanes 2, 4, and 6) . DMSO, the vehicle for resveratrol, did not significantly alter the phosphorylation of ERK1/2 and the expression of Egr-1 (data not shown).