Gata1 regulates PU.1 in DCs. (A) Gata1 and PU.1 ChIP assays were performed with cells from GM-CSF cultures stimulated for 3 days with LPS (+ LPS) or nonstimulated (ST) starting from day 8 of culture. PU.1 ChIP analysis on the PU.1 promoter: amplicon containing PU.1 binding site (PU.1+); amplicon not containing a PU.1 binding site (PU.1−). Gata1 ChIP analysis of the PU.1 promoter: amplicon containing GATA binding site (GATA +); amplicon not containing a GATA binding site (GATA−). Average (± SD) of at least 2 independent experiments analyzed each in triplicate is shown. Corresponding isotype ChIPs (rat IgG or rabbit IgG) are depicted. RFE indicates relative fold enrichment. (B) PU.1 promoter reporter constructs. GATA MUT indicates mutant GATA binding site. (C) GFP expression of the PU.1 promoter reporter constructs in mDCs cultured under standard conditions (ST) and after LPS treatment (LPS) and in proliferating MEL cells (P) and DMSO-induced MEL cells (D). The mean fluorescence intensity (MFI) ± SD obtained from 3 independent experiments is depicted. GFP expression levels with the wild-type promoter are set at 100.