CTCF counter-regulates cardiomyocyte development and maturation programs in the embryonic heart [4C-seq]

Analysis of chromatin architecture suggests that the 3D structure of the genome plays a major role in regulating gene expression, orchestrating the compartmentalization of chromatin and facilitating specific enhancer-promoter interactions. However, the mechanisms that control this structuring of the genome are not fully understood. We have addressed this issue by analyzing the role of CTCF, a major architectural factor in chromatin structure, in the embryonic heart. Loss of CTCF triggered an overall downregulation of the cardiac developmental program, suggesting that CTCF facilitates enhancer-promoter interactions in the developing heart. Detailed analysis of the IrxA gene cluster showed that CTCF loss leads to disruption of the heart-specific regulatory domain that surrounds Irx4, resulting in changes in expression of IrxA cluster genes and neighboring genes. In contrast to the critical role proposed for CTCF in organizing large-scale chromatin domains, our results show that CTCF preferentially mediates local regulatory interactions. 4C-seq of E11.5 mouse embryonic hearts using Irx4 and Ndufs6 promoters and a CTCF binding site as as viewpoints. We have two conditions: control and Ctcf heart Knockout