Lamin B loss in nuclear blebs is rupture dependent while increased DNA damage is rupture independent

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 25, 2025

The nucleus houses genetic information and functions separate from the rest of cell. Loss nuclear shape results in ruptures. Nuclear blebs are deformations identified by decreased DNA density, while lamin B levels vary drastically. To determine if due to rupture, we used immunofluorescence measure emerin, a envelope protein that enriches sites rupture. We observed cell types exhibit also show an enrichment emerin blebs. Oppositely, other types, display maintained B1 showed no enrichment. how rupture affects damage, time lapse imaged dynamics then fixed same cells conduct γH2AX emerin. find damage higher blebbed nuclei independent Thus, confirm loss is have increased Summary statement (180-200 characters): measured effect causes but

Language: Английский

Changes in nuclear and actin mechanics from G1 to G2 affect nuclear integrity

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: April 16, 2025

Abstract The structural integrity of the nucleus is dependent on nuclear mechanical elements chromatin and lamins to resist antagonistic actin cytoskeleton forces. Imbalance results in blebbing, rupture, cellular dysfunction found many human diseases. We used Fluorescent Ubiquitin Cell Cycle Indicator (FUCCI) cells determine how cell cycle changes affect force balance. While blebs are present equally throughout interphase, form predominantly G1 then persist into G2 due increased actin-based confinement focal adhesion density vs. cells. Upon artificial confinement, nuclei ruptured more than nuclei. Single micromanipulation measurements confirmed that stronger both chromatin-based lamin-based stiffness regimes. Decreased can be explained by loss peripheral H3K9me3 from G2, recapitulated inhibition via Chaetocin. cycle-based mechanics impact shape.

Language: Английский

Nuclear blebs are associated with destabilized chromatin packing domains

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: March 29, 2024

ABSTRACT Disrupted nuclear shape is associated with multiple pathological processes including premature aging disorders, cancer-relevant chromosomal rearrangements, and DNA damage. Nuclear blebs (i.e., herniations of the envelope) have been induced by (1) compression, (2) migration (e.g., cancer metastasis), (3) actin contraction, (4) lamin mutation or depletion, (5) heterochromatin enzyme inhibition. Recent work has shown that chromatin transformation a hallmark bleb formation, but higher-order structures in not well understood. As to assemble into nanoscopic packing domains, we investigated if domain organization altered within alteration structure contributed formation. Using Dual-Partial Wave Spectroscopic microscopy, show domains are transformed both B-type depletion inhibition enzymes compared body. Pairing these results single-molecule localization microscopy constitutive heterochromatin, fragmentation domains. Overall, findings indicate translocation fragmented structure. SUMMARY STATEMENT linked various pathologies, disorders. We investigate alterations blebs, revealing

Language: Английский