Extrusion fountains are hallmarks of chromosome organization emerging upon zygotic genome activation - PubMed
6 days ago
- #cohesin loading
- #chromosome organization
- #zygotic genome activation
- Extrusion fountains are key elements of chromosome organization that emerge during zygotic genome activation (ZGA).
- These fountains form early in development, initially accumulating cohesin at enhancers before redistributing to CTCF sites at TAD borders.
- Pioneer transcription factors driving ZGA enhancers are essential for fountain formation, linking enhancer activation to chromosome folding.
- Polymer simulations suggest fountains arise from facilitated cohesin loading, requiring desynchronized loop extrusion, possibly due to cohesin collisions or internal switching.
- Fountains are enhancer-specific and observed in mouse cells, reappearing post-mitosis with cohesin loading, indicating a widespread phenomenon of facilitated loading at enhancers.