Chromatin accessibility profiles across the Eng locus of endothelial and blood progenitor cell lines. (A) Vista plots of sequence alignments of mammalian Eng loci. M, Mus musculus; H, Homo sapiens, and O, Monodelphis domestica. Conserved regions are displayed relative to their positions in the mouse genome (horizontal axis). Segments that show more than 66% sequence identity (indicated on the vertical axis) at the nucleotide level over a 100-bp window are highlighted in pink (noncoding regions) or cyan (coding exons). Exons are displayed above the comparison plots in cyan. Eng exon1 is marked with a block arrow. (B-D) Array-based histone acetylation state (H3Ac ChIP-chip) and DNaseI hypersensitive site profiles across the Eng loci of MS1 endothelial cells, HPC-7 hematopoietic progenitor cells, and BW5147 T-cells. Samples were hybridized in triplicate and fold enrichment over nonenriched input (normalized to the median of values across the Eng locus) is plotted (log₂) against genomic position in kilobases. The width of each bar represents the width of each spotted oligonucleotide on the array. The gray longitudinal bars highlight regions of chromatin accessibility that overlap with genomic regions that are highly conserved in mammals. Accessibility at these conserved regions was either consistent (solid bars) or not (dashed bars) between ChIP-chip and DNaseI hypersensitivity. (B) In endoglin-expressing MS1 endothelial cells, significant enrichments (ie, chromatin accessibility) was noted on both profiles at the Eng promoter (P), the −8kb endothelial enhancer (−8), and also at a 500-bp region 9 kb downstream of the promoter (+9). (C) In endoglin-expressing HPC-7 cells chromatin accessibility was noted on both profiles at the Eng promoter (P) and also at the −8, +7 (∼ 500-bp region 7 kb downstream of the promoter) and +9 regions. (D) In endoglin-nonexpressing BW 5147 cells the Eng promoter (P) was not accessible.