Biology subjects

Flury, V.

Publications and source records attributed to Flury, V..

3 recordsLinked to original sources

bioRxiv2026

FACT depletion results in a temporal cascade of chromatin disruption preceding transcriptional collapse in stem cells

The histone chaperone FACT is essential for chromatin organization and stem cell identity, yet the sequence of events through which FACT maintains chromatin integrity remains unclear. We generate a high-resolution temporal map of events leading to chromatin destabilization and cell identity loss in murine embryonic stem cells following dTAG-mediated depletion of FACT. Loss of FACT initiates a rapid cascade, with nucleosome phasing disruption and reduced H3K4me3 beginning within 10 minutes in a transcription-dependent manner. This architectural destabilization enables pluripotency transcription factors to ectopically occupy gene bodies. FACT loss results in RNA Polymerase II accumulation within 30 minutes and altered H3K36me3 deposition preceding a global transcriptional collapse at 2 hours of FACT depletion. FACT restoration fails to rescue these defects, demonstrating they are largely irreversible. Our findings define a temporal hierarchy in which FACT loss drives progressive deterioration of chromatin architecture, leading to transcriptional collapse in stem cells.

genomics↗

bioRxiv2026

Unified function of FACT in mammalian chromatin replication and transcription, dissolving and restoring nucleosomes to counteract genome aggregation

Nucleosomes with their associated modifications underlie genome organisation and regulation. Replication and transcription require nucleosome disassembly to access the DNA template. How this is orchestrated without jeopardizing chromatin function remains unknown. Here, we reveal a general, global requirement of the histone chaperone FACT in mammalian replication, transcription and chromatin maintenance. Upon acute FACT depletion, replisome and RNA polymerase progression is halted genome-wide and chromatin structure in their wake collapses with reduced nucleosome occupancy, irregular spacing and intermediate assemblies. Chromatin states deteriorate as modified histones are lost due to a lack of histone recycling. Chromatin fiber disorder further manifests in the 3D genome, triggering active genes to coalesce in aberrant microcompartments. This establishes a unifying mechanistic basis for mammalian chromatin replication and transcription, with FACT mediating nucleosome disruption and re-assembly and thereby guarding against spurious chromatin aggregation. Nucleosome organization can therefore dynamically regulate genome architecture.

molecular biology↗

bioRxiv2021

NASP maintains histone H3-H4 homeostasis through two distinct H3 binding modes

Histone chaperones regulate all aspects of histone metabolism. NASP is a major histone chaperone for H3-H4 dimers critical for preventing histone degradation. Here, we identify two distinct histone binding modes of NASP and reveal how they cooperate to ensure histone H3-H4 supply. We determine the structures of a sNASP dimer, a complex of sNASP with an H3 3 peptide, and the sNASP-H3-H4-ASF1b co-chaperone complex. This captures distinct functionalities of NASP and identifies two distinct binding modes involving the H3 3 helix and the H3 N region, respectively. Functional studies demonstrate the H3 N-interaction represents the major binding mode of NASP in cells and shielding of the H3 N region by NASP is essential in maintaining the H3-H4 histone soluble pool. In conclusion, our studies uncover the molecular basis of NASP as a major H3-H4 chaperone in guarding histone homeostasis.

biochemistry↗