CD154 promoter activity in untreated and PMA-differentiated cell lines. (A) Untreated and 4-day PMA-differentiated CMK, Meg-01, and K562 cells were transfected with the promoter construct shown. Twenty-four hours later, luciferase activity was assessed. Fold induction of luciferase activity in the differentiated cells relative to the untreated cells (Untx) is shown. The bars represent means plus or minus the standard error from 4 independent experiments. (B) Relative luciferase activity of 4-day PMA-differentiated CMK cells transfected with the CD154 promoter-reporter constructs shown. The −391 to +65 nt region of the CD154 with putative transcription factor binding sites is shown. The bars represent means plus or minus the standard error from 4 independent experiments. The sequence of the −391 nt 5′ flanking region with location of the consensus transcription factor binding sites as predicted by Matinspector. The consensus core sequences for GATA-1, NFAT, and Ets-1 are as follows: GATA-1 (GATA), NFAT (TTTTCC) and Ets-1 (GGAA)