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Abstract：
Haploinsufficiency of the chromo-domain protein CHD7 underlies most cases of CHARGE syndrome, a multisystem birth defect including congenital heart malformation. Context specific roles for CHD7 in various stem, progenitor, and differentiated cell lineages have been reported. Previously, we showed severe defects when Chd7 is absent from cardiopharyngeal mesoderm (CPM). Here, we investigate altered gene expression in the CPM and identify specific CHD7-bound target genes with known roles in the morphogenesis of affected structures.
We generated conditional KO of Chd7 in CPM and analysed cardiac progenitor cells using transcriptomic and epigenomic analyses, in vivo expression analysis, and bioinformatic comparisons with existing datasets. We show CHD7 is required for correct expression of several genes established as major players in cardiac development, especially within the second heart field (SHF). We identified CHD7 binding sites in cardiac progenitor cells and found strong association with histone marks suggestive of dynamically regulated enhancers during the mesodermal to cardiac progenitor transition of mESC differentiation. Moreover, CHD7 shares a subset of its target sites with ISL1, a pioneer transcription factor in the cardiogenic gene regulatory network, including one enhancer modulating Fgf10 expression in SHF progenitor cells vs. differentiating cardiomyocytes.
We show that CHD7 interacts with ISL1, binds ISL1-regulated cardiac enhancers, and modulates gene expression across the mesodermal heart fields during cardiac morphogenesis.
We generated conditional KO of Chd7 in CPM and analysed cardiac progenitor cells using transcriptomic and epigenomic analyses, in vivo expression analysis, and bioinformatic comparisons with existing datasets. We show CHD7 is required for correct expression of several genes established as major players in cardiac development, especially within the second heart field (SHF). We identified CHD7 binding sites in cardiac progenitor cells and found strong association with histone marks suggestive of dynamically regulated enhancers during the mesodermal to cardiac progenitor transition of mESC differentiation. Moreover, CHD7 shares a subset of its target sites with ISL1, a pioneer transcription factor in the cardiogenic gene regulatory network, including one enhancer modulating Fgf10 expression in SHF progenitor cells vs. differentiating cardiomyocytes.
We show that CHD7 interacts with ISL1, binds ISL1-regulated cardiac enhancers, and modulates gene expression across the mesodermal heart fields during cardiac morphogenesis.
摘要：
目的：大多数CHARGE综合征病例是CHD7染色体结构域蛋白单倍功能不全的基础，包括先天性心脏畸形在内的多系统出生缺陷。CHD7在各种词干中的特定于上下文的角色，已经报道了祖细胞和分化细胞系。以前，当Chd7不存在于心咽中胚层（CPM）时，我们显示出严重的缺陷。在这里，我们研究了CPM中改变的基因表达，并鉴定了在受影响结构的形态发生中具有已知作用的特定CHD7结合的靶基因。
结果：我们在CPM中生成了Chd7的条件性KO，并使用转录组和表观基因组分析分析了心脏祖细胞，体内表达分析，以及与现有数据集的生物信息学比较。我们表明CHD7是正确表达几个在心脏发育中被确立为主要参与者的基因所必需的。尤其是在第二心脏领域（SHF）。我们确定了心脏祖细胞中的CHD7结合位点，并发现与组蛋白标记的强烈关联，提示在mESC分化的中胚层到心脏祖细胞的过渡过程中动态调节的增强剂。此外，CHD7与ISL1共享其靶位点的子集，ISL1是心源性基因调控网络中的先驱转录因子，包括一个增强子调节SHF祖细胞与分化心肌细胞中的Fgf10表达。
结论：我们显示CHD7与ISL1相互作用，结合ISL1调节的心脏增强子，并在心脏形态发生过程中调节跨中胚层心脏区域的基因表达。
■CHD7是CHARGE综合征中单倍体不足的染色质重塑者，与自闭症谱系障碍和各种癌症有关。该综合征中的心脏缺陷通过小鼠在两个谱系中的功能丧失来概括，神经c和心咽中胚层（CPM）。CHD7通过主要与通常与先驱转录因子ISL1共享的位点远离靶基因的增强子结合来调节重要的心源性基因。CHD7结合的增强子元件在中胚层到心脏祖细胞转变期间显示组蛋白修饰的高度动态转换。因此，CHD7活性的操纵可能有助于不同心血管祖细胞的定向分化,用于再生/修复治疗.
结果：我们在CPM中生成了Chd7的条件性KO，并使用转录组和表观基因组分析分析了心脏祖细胞，体内表达分析，以及与现有数据集的生物信息学比较。我们表明CHD7是正确表达几个在心脏发育中被确立为主要参与者的基因所必需的。尤其是在第二心脏领域（SHF）。我们确定了心脏祖细胞中的CHD7结合位点，并发现与组蛋白标记的强烈关联，提示在mESC分化的中胚层到心脏祖细胞的过渡过程中动态调节的增强剂。此外，CHD7与ISL1共享其靶位点的子集，ISL1是心源性基因调控网络中的先驱转录因子，包括一个增强子调节SHF祖细胞与分化心肌细胞中的Fgf10表达。
结论：我们显示CHD7与ISL1相互作用，结合ISL1调节的心脏增强子，并在心脏形态发生过程中调节跨中胚层心脏区域的基因表达。
■CHD7是CHARGE综合征中单倍体不足的染色质重塑者，与自闭症谱系障碍和各种癌症有关。该综合征中的心脏缺陷通过小鼠在两个谱系中的功能丧失来概括，神经c和心咽中胚层（CPM）。CHD7通过主要与通常与先驱转录因子ISL1共享的位点远离靶基因的增强子结合来调节重要的心源性基因。CHD7结合的增强子元件在中胚层到心脏祖细胞转变期间显示组蛋白修饰的高度动态转换。因此，CHD7活性的操纵可能有助于不同心血管祖细胞的定向分化,用于再生/修复治疗.
