RNA polymerase I transcription is essential for establishing the chromatin architecture in mouse but not in human embryos [ChIP-seq]

The distinctions in 3D genome between humans and mice, as well as the mechanisms underlying de novo organization, remain unexplored. Our study revealed an extensive reorganization of the 3D genome from human oogenesis to early embryogenesis, displaying significant differences to the mouse, notably dramatically attenuated TADs at GV stage in human. The 3D genome reconstruction timing also differs between species, which it initiates at the 4-cell stage in human, while in mouse, it commences at the 2-cell stage in mouse. We discovered that RNA polymerase I (Pol I) is crucial for establishing the chromatin structures during mouse embryogenesis, but not in human embryos. Intriguingly, the absence of Pol I transcription weakens TAD structure in mouse female germline stem cells, whereas it fortifies it in human counterparts. Our findings provide valuable insights into chromatin organization during germ cell and embryonic development and have implications for fertility preservation and birth defect prevention.