HNF4α protein level, predicted binding sites and ChIP-chip results for HNF4α and acHis3. A) Western Blot of HNF4α and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in nuclear extracts from undifferentiated and differentiated Caco2 cells. B) Distribution of HNF4α binding sites. The positions of HNF4α binding sites were determined in promoters of genes that are up-regulated during differentiation of Caco-2 cells using the M00411 matrix from the Transfac database http://www.biobase.de/ and the PRIMO program http://gastro.sund.ku.dk/primo/. The number of HNF4α hits (Y-axis) was determined in 100 bp intervals from position -1350 to +150 (X-axis). C) Distribution of probes giving a positive signal (> two-fold enrichment) in the HNF4α ChIP-chip analysis. D) Distribution of probes giving a positive signal (>four-fold enrichment) in the acetylated histone H3 ChIP-chip analysis.