Transcriptional requirement of BET proteins after establishment of GATA1 occupancy. (A) ChIP for BRD4 and GATA1 in G1E GATA1-ER cells treated with 250 nM JQ1 for up to 60 minutes following GATA1 induction. Cd4 served as negative control. Error bars represent SEM; n = 3. *P < .05 that indicated JQ1-treated sample mRNA is lower than untreated (2-sample t test). (B) Primary transcript RT-qPCR of indicated transcripts following JQ1 treatment in GATA1-induced cells. Error bars represent SEM; n = 4. *P < .05 comparing JQ1 treated and control samples (2-sample t test).