Anp32e protects against accumulation of H2A.Z at Sox motif containing promoters during zebrafish gastrulation

Epigenetic regulation of chromatin states is crucial for proper gene expression programs and progression during development, but precise mechanisms by which epigenetic factors influence differentiation remain poorly understood. Here we find that the histone variant H2A.Z accumulates at Sox motif-containing promoters during zebrafish gastrulation while neighboring genes become transcriptionally active. These changes coincide with reduced expression of anp32e, the H2A.Z histone removal chaperone, suggesting that loss of Anp32e may lead to increases in H2A.Z binding during differentiation. Remarkably, genetic removal of Anp32e in embryos leads to H2A.Z accumulation prior to gastrulation and developmental genes become precociously active. Accordingly, H2A.Z accumulation occurs most extensively at Sox motif-associated genes, including many which are normally activated following gastrulation. Altogether, our results provide compelling evidence for a mechanism in which Anp32e preferentially restricts H2A.Z accumulation at Sox motifs to regulate the initial phases of developmental differentiation in zebrafish. Overall design: Genomic profiles of H2A.Z and Anp32e were examined by CUT&Tag in developing zebrafish embryos

染色质状态的表观遗传调控，对于发育过程中正常基因表达程序的执行与进程至关重要，但表观遗传因子影响细胞分化的确切机制仍不甚明晰。本研究发现，在斑马鱼原肠胚形成过程中，组蛋白变体H2A.Z会在含有Sox基序的启动子区域富集，而其邻近基因随即发生转录激活。上述变化与H2A.Z组蛋白移除分子伴侣anp32e的表达下调相吻合，这提示在细胞分化过程中，Anp32e的缺失可能会增强H2A.Z的结合。值得注意的是，在胚胎中敲除Anp32e后，H2A.Z会在原肠胚形成前就发生富集，发育相关基因也因此提前激活。相应地，H2A.Z的富集主要发生在与Sox基序相关的基因上，其中包含大量通常在原肠胚形成后才会被激活的基因。综上，本研究结果提供了强有力的证据，证明Anp32e可通过优先限制Sox基序区域的H2A.Z富集，来调控斑马鱼发育分化的初始阶段。实验整体设计：本研究通过CUT&Tag技术，对发育中的斑马鱼胚胎中H2A.Z与Anp32e的基因组图谱进行了检测。