Regulatory mechanism of dynamic CTCF binding. (A) Relative expression of RBM38 in WT HUDEP-2 cells and 2 mut clones, as compared with HPRT1 before differentiation (D0) and 3 days after induced maturation (D3). D0, n = 2; D3, n > 3. **P < .01, paired 2-tailed t test. (B) ChIP-seq signal tracks of GATA1 and H3K27ac in WT HUDEP-2 cells and 2 mut clones after 3 days of induced maturation. The dynamic CTCF site that harbors the deleted motif is highlighted. (C) Capture Hi-C results with baits targeting the promoter of the RBM38 gene in WT HUDEP-2 cells and a mut clone before differentiation (D0) and 3 days after induced maturation (D3). The targeted CTCF-binding site is highlighted in pink. (D) Chromatin loops identified by H3K27ac HiChIP that are anchored within the targeted dynamic CTCF-binding site in WT HUDEP-2 cells and a mutant clone after 3 days of induced maturation. The top panel shows a 2.8-Mb window, and the bottom panel zooms in on a 265-kb window. The targeted CTCF-binding site is highlighted. (E) Schematic model of the regulatory mechanism of dynamic CTCF-binding site. chr, chromosome.