Fig. 2.

Progenitor cell competence for sensory differentiation is associated with emergence of newly established accessible chromatin regions. (A) A Heatmap demonstrates that most of the ATAC-seq accessible genomic regions (orange) newly emerged during the transition from E12.0 to E13.5 (13,352 peaks) remain open in E17.5 HC and supporting cells (SC), and gradually lose accessibility in the postnatal supporting cells (P6 SC). Out of 13,352, 3,163 genomic loci are bound by Atoh1 in E17.5 HC (Atoh1 Cut&Run, blue). Scale of each sample column is ±3 kb from the center the peaks. (B) GO analysis using GREAT shows the top six most-enriched biological process terms for E13.5 newly accessible peaks. (C) Violin plots show that expression [Log₁₀(FPKM+1)] of the genes in the cell fate commitment GO term is significantly up-regulated in E13.5 progenitors and then down-regulated in E17.5 supporting cells and hair cells (Wilcoxon signed-rank test). (D) The same analysis shows that expression of hair cell–specific and supporting cell–specific genes in the inner ear morphogenesis GO term is unchanged at E13.5 but is significantly up-regulated upon differentiation (Wilcoxon signed-rank test). (E) Integrative Genomics Viewer (IGV) tracks show ATAC-seq profiles of representative genomic loci of hair cell–specific (Atoh1, Myo6) and supporting cell–specific genes (Hes5, Prox1) at E12.0 and E13.5. Their putative enhancers that gain accessibility at E13.5 are highlighted in gray boxes. (F) The expression of the hair cell– and supporting cell–specific genes shown in E is shown in E12.0 and E13.5 progenitor cells (Prog) and in E17.5 and P1 HC or supporting cells (SC).