Show Notes
Gao J et al., Nat Commun - H4 tail lysine residues drive liquid-liquid phase separation of 12‑mer nucleosome arrays, while H3 tail acetylation and the histone chaperone Nap1 increase internal dynamics and lower droplet viscosity. Key terms: Nap1, H3 acetylation, H4 acetylation, liquid-liquid phase separation, nucleosome arrays.
Study Highlights:
H4 tail lysine residues are the primary drivers of nucleosome array phase separation, and H4-tail acetylation prevents droplet formation. H3 tail acetylation mimic (H3KQ) and in situ H3 acetylation speed fluorescence recovery, indicating enhanced DNA–histone dynamics. Nap1 dissolves gel-like aggregates formed by tailless H3 arrays, increases nucleosome concentration inside droplets from ~326 µM to ~491 µM, and accelerates internal dynamics. STORM imaging reveals condensed droplets contain both a mobile fraction and a relatively immobile structural scaffold. Optical-tweezers microrheology identifies two relaxation components and shows Nap1 and H3KQ specifically lower the relaxation time and viscosity of the slower scaffold-associated component
Conclusion:
Histone H4 tail lysines govern chromatin phase separation while H3 acetylation and Nap1 tune the fluidity and accessibility of condensed chromatin
Music:
Enjoy the music based on this article at the end of the episode.
Reference:
Gao J, Li H, Tan S, Zhou R & Lee T-H. Roles of histone chaperone Nap1 and histone acetylation in regulating phase-separation of nucleosome arrays. Nature Communications. 2025;16:10672. https://doi.org/10.1038/s41467-025-65701-3
License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/
Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00
Official website https://basebybase.com
On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics.
Episode link: https://basebybase.castos.com/episodes/nap1-histone-acetylation
Episode Slug: nap1-histone-acetylation
