Allelic reprogramming of 3D chromatin architecture during early mammalian development

In mammals, chromatin undergoes reorganization after fertilization, but little is known about the molecular basis for reprogramming of higher-order chromatin structure. Here, Wei Xie and colleagues have developed a low-input Hi-C approach, which they apply to examine chromatin organization in mouse oocytes and preimplantation embryos. They find that chromatin has markedly reduced higher-order structure for both parental genomes after fertilization. Topological associated domain boundaries and chromatin compartments start to emerge in zygotes but the subsequent maturation of three-dimensional chromatin architecture is surprisingly slow.