Effect of HDAC5 knockdown on chromatin accessibility. (A) PCA of ATAC-seq data demonstrates a high degree of separation of samples after treatment with shHDAC5 compared with the control (circled). HDAC5 shRNA-treated and control samples are compared with erythroid stage-specific samples derived from human umbilical cord blood. (B) The number of genomic regions with different chromatin accessibility between control and HDAC5 shRNA-treated cells. HDAC5 knockdown resulted in a large increase in chromatin accessibility in orthochromatic erythroblasts compared with the control. (C) Heat map display of chromatin accessibility levels in genomic regions that become accessible in orthochromatic erythroblasts after treatment with shHDAC5. The top section shows average profiles for all regions, and the bottom section shows levels for individual regions in the 6-kb area surrounding the summits of the ATAC peaks . EBaso, Early-stage basophilic erythroblasts; LBaso, Late-stage basophilic erythroblasts; Ortho, orthochromatic erythroblasts; Poly, poly chromatic erythroblasts; Pro, proerythroblasts.