||3D Chromatin Structures of Mature Gametes and Structure Reprogramming duringMammalian Embryogenesis
Mus musculus cytomegalovirus 2
||The dynamics of 3D chromatin structures during mammalian embryo development remains limited known. We report the 3D chromatin architectures of mouse gametes and early embryos using an optimized Hi-C method with low-cell samples. We find that the mature oocytes at metaphase II stage do not have topologically associated domains. In sperm, the extra-long range interactions (>4 mega bases) and interchromosomal interactions are more frequent. The high-order structures of both the paternal and maternal genomes in zygotes and 2-cell embryos are obscure. The chromatin structures are gradually re-established through development. We find that the unmethylatedCpGs are enriched in A compartment, and the decreased levels of CpG methylation in A compartment are higher than those in B compartment in embryos. Furthermore, the establishment of TAD structure requires DNA replication in 2-cell embryos, but not zygotic genome activation. In summary, the global reprogramming of the chromatin architecture occurs during early mammalian development.
||3D Chromatin Structures of Mature Gametes and Structural Reprogramming during Mammalian Embryogenesis.