Institute of Molecular Biology, 55128 Mainz, Germany.
Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands.
Cell Rep. 2018 Jul 3;24(1):1-10.e4. doi: 10.1016/j.celrep.2018.06.003.
The spatial organization of chromosomes is critical in establishing gene expression programs. We generated in situ Hi-C maps throughout zebrafish development to gain insight into higher-order chromatin organization and dynamics. Zebrafish chromosomes segregate in active and inactive chromatin (A/B compartments), which are further organized into topologically associating domains (TADs). Zebrafish A/B compartments and TADs have genomic features similar to those of their mammalian counterparts, including evolutionary conservation and enrichment of CTCF binding sites at TAD borders. At the earliest time point, when there is no zygotic transcription, the genome is highly structured. After zygotic genome activation (ZGA), the genome loses structural features, which are re-established throughout early development. Despite the absence of structural features, we see clustering of super-enhancers in the 3D genome. Our results provide insight into vertebrate genome organization and demonstrate that the developing zebrafish embryo is a powerful model system to study the dynamics of nuclear organization.
染色体的空间组织对于建立基因表达程序至关重要。我们在整个斑马鱼发育过程中生成了原位 Hi-C 图谱,以深入了解高级染色质组织和动态。斑马鱼染色体分离为活性和非活性染色质(A/B 区室),这些区室进一步组织成拓扑关联域(TAD)。斑马鱼 A/B 区室和 TAD 具有与哺乳动物同源物相似的基因组特征,包括 TAD 边界处 CTCF 结合位点的进化保守性和富集。在最早的时间点,即没有合子转录时,基因组高度结构化。在合子基因组激活(ZGA)之后,基因组失去结构特征,这些特征在整个早期发育过程中重新建立。尽管没有结构特征,但我们在 3D 基因组中看到了超级增强子的聚类。我们的结果提供了对脊椎动物基因组组织的深入了解,并证明发育中的斑马鱼胚胎是研究核组织动态的强大模型系统。