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Nucleosome turnover concomitant with incorporation of the replication-independent histone variant H3.3 is a hallmark of regulatory regions in the animal genome. Nucleosome turnover is known to be universally linked to DNA accessibility and histone acetylation. In mouse embryonic stem cells, H3.3 is also highly enriched at interstitial heterochromatin, most prominently at intracisternal A-particle endogenous retroviral elements. Interstitial heterochromatin is established over confined domains by the TRIM28-KAP1/SETDB1 corepressor complex and has stereotypical features of repressive chromatin, such as H3K9me3 and recruitment of all HP1 isoforms. Here, we demonstrate that fast histone turnover and H3.3 incorporation is compatible with these hallmarks of heterochromatin. Further, we find that Smarcad1 chromatin remodeler evicts nucleosomes generating accessible DNA. Free DNA is repackaged via DAXX-mediated nucleosome assembly with histone variant H3.3 in this dynamic heterochromatin state. Loss of H3.3 in mouse embryonic stem cells elicits a highly specific opening of interstitial heterochromatin with minimal effects on other silent or active regions of the genome.
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http://dx.doi.org/10.1038/s41467-020-18863-1 | DOI Listing |
Development
September 2025
MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
In an era of expanding reproductive possibilities, the human embryo has come to represent both immense potential and profound constraint. Advances in medically assisted reproduction (MAR) have led to the cryopreservation of hundreds of thousands of embryos each year, yet many remain unused and are ultimately discarded. Meanwhile, studies aimed at understanding infertility, early human development and preventing miscarriage continue to face significant barriers, with only a small fraction of embryos ever donated to research.
View Article and Find Full Text PDFJ Genet Genomics
September 2025
Institute of Pediatrics, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; Sh
Chromodomain helicase DNA binding protein 7 (CHD7), an ATP-dependent chromatin remodeler, plays versatile roles in neurodevelopment. However, the functional significance of its ATPase/nucleosome remodeling activity remains incompletely understood. Here, we generate genetically engineered mouse embryonic stem cell lines harboring either an inducible Chd7 knockout or an ATPase-deficient missense variant identified in individuals with CHD7-related disorders.
View Article and Find Full Text PDFVascul Pharmacol
September 2025
Department of Orthopaedic Surgery, Orthopaedic Hospital Research Center, UCLA, Los Angeles, CA 90095, USA; Center for Cardiovascular Science, University of Edinburgh, Edinburgh, UK. Electronic address:
The walls of all embryonic, foetal, and adult blood vessels contain mesodermal progenitors, distributed as pericytes in capillaries and micro vessels, and fibroblastic cells in the tunica adventitia of larger veins and arteries. Following dissociation, selection by flow cytometry, and culture, those perivascular cells turn into bona fide mesenchymal stem cells of which they possess all attributes. In vivo, the adventitial cellular niche supports several spatially-organized subsets of mesodermal progenitors biased toward either osteo-, adipo-, or fibrogenesis, and dominated by more primitive, multi-lineage stem-like cells.
View Article and Find Full Text PDFDNA Repair (Amst)
August 2025
Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Radiotherapy, Erasmus MC Cancer Institute, Erasmus University Med
DNA crosslink-inducing drugs are widely used in clinical settings for treatment of solid tumors. Double strand breaks (DSBs) that arise during interstrand crosslink (ICL) repair are crucial determinants of the therapeutic response, as they lead to cell death if not repaired. DSBs can be repaired through non-homologous end joining (NHEJ), theta-mediated end joining (TMEJ), and homologous recombination (HR).
View Article and Find Full Text PDFCell Rep
September 2025
Virginia Tech Fralin Biomedical Research Institute Cancer Research Center DC, Children's National Research & Innovation Campus, Washington, DC, USA; Department of Biomedical Sciences and Pathobiology (DBSP), Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA; Center
Nuclear receptor binding set domain protein 1 (NSD1) is a key histone methyltransferase that catalyzes di-methylation of lysine 36 of histone H3 (H3K36me2), essential for active chromatin domains. While the loss of NSD1 activity halts embryonic development and its aberrant gain drives oncogenesis in leukemia and glioma, the regulatory mechanisms remain poorly understood. Here, we uncover that NSD1 requires allosteric activation through the aromatic pocket of its Pro-Trp-Trp-Pro 2 (PWWP2) domain.
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