CTCF changes and their correlation with histone marks and effects on cell differentiation. (A) ChIP-seq on histone marks (H3K18ac, H3K27ac, H3K4me1, and H2AZ) displays changes in histone modifications around gained (left) and lost (right) CTCF-binding sites between AMLall and NBM. (B) CTCF expression by real-time quantitative PCR following its knockdown in K562 cells. Relative gene expression was calculated using 2−ΔΔCt against GAPDH, while scramble control was set to 1 (dashed line) and knockdown was normalized against the scramble (P < .05; Student t test). (C) Western plot showing CTCF protein levels following CTCF knockdown. (D) CD61 and Ki67 expression by real-time quantitative PCR in K562 after CTCF knockdown; normalization was done as described in panel B. (E) Detection of surface marker CD61 on K562-CTCF knockdown by FACS. Mean florescence intensity was used to calculate the expression level of CD61 after normalization against untransfected K562 cells (P < .001; Student t test). *P < .05, **P < .01, ***P < .001.