FIGURE 5.

RARγ and RNA pol II binding to the Hoxa1, Hoxb1, and Cyp26a1 genes. A–F, RARγ ChIP was performed following dual cross-linking with disuccinimidyl glutarate and then formaldehyde. G–L, pol II Ser(P)-5 ChIP was performed following formaldehyde cross-linking. For all panels, WT, RARE-KO, and RARγ-KO ESCs were cultured ± 1 μm RA for 0, 1, or 8 h prior to cross-linking. ChIP DNA was quantified by quantitative PCR and is reported as percent enrichment of input (filled symbols, solid lines). Also shown are results using IgG as a negative control (open symbols, dotted lines). As an additional negative control we show enrichment at an intergenic region ∼18 kb 3′ of Hoxb1 (F and L). The loci analyzed are shown at the top of the figure. Each experiment was repeated 2–5 times, and data are reported as mean ± S.E.