Base by Base

232: Lamin A/C steers fork restart via H3K9me3 and PARylation


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️Episode 232: Lamin A/C steers fork restart via H3K9me3 and PARylation

In this episode of PaperCast Base by Base, we explore Nucleoplasmic Lamin A/C, together with LAP2α, enforces active replication fork slowing during mild replication stress by promoting local H3K9me3 and ADP-ribosylation to restrain RECQ1-mediated restart and protect genome stability

Study Highlights:
Lamin A/C dynamically associates with replication factories throughout the nucleus and its acute depletion abolishes stress-induced fork slowing and increases chromosomal breakage. Loss of nucleoplasmic Lamin A/C or LAP2α reduces poly-ADP-ribosylation (PAR) at nascent DNA, leading to untimely RECQ1-dependent restart of reversed forks. Mild replication stress induces accumulation of H3K9me3 at replication forks, and Lamin A/C is required to maintain this mark by preventing its removal by the demethylase KDM3A/JMJD1A. Inhibiting G9a to prevent H3K9 methylation phenocopies Lamin A/C loss, reducing PAR at forks and deregulating RECQ1 restart, whereas PARG inhibition or KDM3A downregulation restores PAR levels and fork slowing.

Conclusion:
Nucleoplasmic Lamin A/C maintains local chromatin compaction and PARylation at replication factories to limit RECQ1 activity, enforce fork slowing under mild stress, and preserve genome stability

Music:
Enjoy the music based on this article at the end of the episode.

Reference:
Cherdyntseva V, Paulson J, González-Acosta D, Ubieto-Capella P, Rodrigues M, Aouami M, Adakli S, Gagné J-P, Bakker C, Poirier GG, Taneja N, Lopes M. Nucleoplasmic Lamin A/C controls replication fork restart upon stress by modulating local H3K9me3 and ADP-ribosylation levels. Nat Commun. 2025. https://doi.org/10.1038/s41467-025-66098-9

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/

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Base by BaseBy Gustavo Barra