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Interphase nuclear architecture is disrupted and rapidly reformed with each cell division cycle. Successive cell generations exhibit a "memory" of this nuclear architecture, as well as for gene expression. Furthermore, many features of nuclear and mitotic chromosome structure are recognizably species and tissue specific. We wish to know what properties of the underlying chromatin structure may determine these conserved features of nuclear architecture. Employing a particular mouse autoimmune anti-nucleosome monoclonal antibody (PL2-6), combined with deconvolution immunofluorescence microscopy, we present evidence for a unique epitope (involving a ternary complex of histones H2A and H2B and DNA) which is localized only at the exterior chromatin surface of interphase nuclei and mitotic chromosomes in mammalian, invertebrate and plant systems. As only the surface chromatin region is identified with antibody PL2-6, we have assigned it the name "epichromatin". We describe an "epichromatin hypothesis", suggesting that epichromatin may have a unique evolutionary conserved conformation which facilitates interaction with the reforming post-mitotic nuclear envelope and a rapid return of interphase nuclear architecture.
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http://dx.doi.org/10.4161/nucl.2.1.13271 | DOI Listing |
G3 (Bethesda)
September 2025
INRAE, UR629 URFM, Ecologie des Forêts Méditerranéennes, Site Agroparc, Domaine Saint Paul, F-84914 Avignon Cedex 9, France.
Symphonia globulifera (Clusiaceae) has emerged as a model organism in tropical forest ecology and evolution due to its significant ecological role and complex biogeographical history. Originating from Africa, this species has independently colonized Caribbean, Central and South America three times, becoming a key component of tropical ecosystems across these regions. Despite the ecological importance of S.
View Article and Find Full Text PDFComput Struct Biotechnol J
August 2025
Institut de Recherche en Cancérologie de Montpellier (IRCM), Équipe Labellisée Ligue Contre le Cancer, INSERM U1194, Université de Montpellier, Institut régional du Cancer de Montpellier (ICM), Montpellier, France.
Digital twins (DTs) are emerging tools for simulating and optimizing therapeutic protocols in personalized nuclear medicine. In this paper, we present a modular pipeline for constructing patient-specific DTs aimed at assessing and improving dosimetry protocols in PRRT such as therapy. The pipeline integrates three components: (i) an anatomical DT, generated by registering patient CT scans with an anthropomorphic model; (ii) a functional DT, based on a physiologically-based pharmacokinetic (PBPK) model created in SimBiology; and (iii) a virtual clinical trial module using GATE to simulate particle transport, image simulation, and absorbed dose distribution.
View Article and Find Full Text PDFDalton Trans
September 2025
Section for Solid State and Theoretical Inorganic Chemistry, Institute of Inorganic Chemistry, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
A series of niobium oxyiodide compounds has recently been identified using a non-conventional reduction method. The continuation of these studies of heterogeneous solid-state reactions in a closed system has led to the crystallization and structural analysis of two novel compounds LiNbOI and NbOI(NbI). Both crystal structures are derived from the pentanuclear [NbO] cluster core and are expanded through the incorporation of additional niobium atoms, forming new [NbO] and [NbO] cluster cores.
View Article and Find Full Text PDFNat Rev Mol Cell Biol
September 2025
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
The defining property of eukaryotic cells is the storage of heritable genetic material in a nuclear compartment. For eukaryotic cells to carry out the myriad biochemical processes necessary for their function, macromolecules must be efficiently exchanged between the nucleus and cytoplasm. The nuclear pore complex (NPC) - which is a massive assembly of ~35 different proteins present in multiple copies totalling ~1,000 protein subunits and architecturally conserved across eukaryotes - establishes a size-selective channel for regulated bidirectional transport of folded macromolecules and macromolecular assemblies across the nuclear envelope.
View Article and Find Full Text PDFCell Chem Biol
September 2025
iHuman Institute, ShanghaiTech University, Shanghai 201210, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, CA 92037, USA; Institute of Molecular Biology and Bio
Balanced or biased G protein and arrestin transmembrane signaling by the adenosine 2A receptor (AAR) is related to ligand-induced allosterically triggered variation of structural dynamics in the intracellular half of the transmembrane domain (TMD). F-nuclear magnetic resonance (NMR) of a network of genetically introduced meta-trifluoromethyl-L-phenylalanine (mtfF) probes in the core of the TMD revealed signaling-related structure rearrangements leading from the extracellular orthosteric drug-binding site to the G protein and arrestin contacts on the intracellular surface. The key element in this structural basis of signal transfer is dynamic loss of structural order in the intracellular half of the TMD, as manifested by local polymorphisms and associated rate processes within the molecular architecture determined previously by X-ray crystallography.
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