Hes-1 contributes to GATA-2–mediated regulation of myeloid progenitor cell function. RNA prepared from the GMPs of each genotype was subjected to reverse-transcriptase reaction, and Q-PCR for Hes-1 was performed (A). Results were normalized to HPRT. Triplicates were used for each PCR, and the figures represent 4 experiments ± SEM (P = .005). RNA was prepared from GFP⁺ cells of GMPs that were transduced with either llx and llx–GATA-2. These RNA samples were subjected to a reverse-transcriptase reaction, and Q-PCR for Hes-1 was performed. Results were normalized to HPRT (B) (n = 2; P = not determined). ChIP experiments in 32Dcl3 cells showed that GATA-2 binds directly to the HES-1 locus. Four putative GATA-binding sites were tested, one of which was preferentially enriched by the anti–GATA-2 antibody (primer set 4). ChIP material was analyzed by SYBRGreen qPCR; data are the mean of 4 experiments read in duplicate. Results are represented as enrichments over nonspecific binding by total rabbit IgG after normalization to a control sequence (exon 4 of HES-1). (C) Bone marrow–nucleated cells from each genotype were sorted for GMPs and transduced with either empty vector or HES-1. GFP⁺ cells from each genotype were plated in colony-forming medium containing myeloid, megakaryocyte, and erythroid growth factors. Granulocyte-macrophage progenitors were tallied on day 10 and are depicted (D) (n = 3; GATA-2^+/+ empty vector vs GATA-2^+/− empty vector, P = .047; GATA-2^+/− empty vector vs GATA-2^+/−HES-1, P = .049). ** indicates statistical significance. Error bars indicate SEM. Statistical analysis was performed by using the paired Student t test.