FIGURE 4.
Egr-1 augments CD154 transcription. Primary human CD4 T cells were transiently transfected with a firefly luciferase reporter plasmid driven by the proximal hCD154 promoter (10). A, The cells were cotransfected with expression plasmids for Egr-1, Egr-2, Egr-3, or control (empty vector). After a brief rest, the cells were activated for 6 h with medium alone or phorbol ester and ionomycin (P+I). Cell lysates were analyzed in duplicate for luciferase activity and corrected for transfection efficiency with a cotransfected Renilla luciferase control plasmid. Results are representative of one of five similar experiments. B, Primary CD4 T cells were transfected with expression plasmids for Egr-1, NFAT1, Egr-1+NFAT1, or controls (empty vectors). The cells were activated for 6 h with P+I, and cell lysates were analyzed for luciferase activity. Results are representative of one of four similar experiments.