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Nucleosomes occupy a central role in regulating eukaryotic gene expression by blocking access of transcription factors to their target sites on chromosomal DNA. Analysis of chromatin structure and function has mostly been performed by probing DNA accessibility with endonucleases. Such experiments average over large numbers of molecules of the same gene, and more recently, over entire genomes. However, both digestion and averaging erase the structural variation between molecules indicative of dynamic behavior, which must be reconstructed for any theory of regulation. Solution of this problem requires the structural analysis of single gene molecules. In this chapter, we describe a method by which single gene molecules are purified from the yeast Saccharomyces cerevisiae and cross-linked with psoralen, allowing the determination of nucleosome configurations by transmission electron microscopy. We also provide custom analysis software that semi-automates the analysis of micrograph data. This single-gene technique enables detailed examination of chromatin structure at any genomic locus in yeast.
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http://dx.doi.org/10.1007/978-1-4939-1680-1_9 | DOI Listing |
Future Med Chem
September 2025
Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou, P.R. China.
The nuclear receptor binding SET domain (NSD) family of histone methyltransferases, which comprised NSD1, NSD2, and NSD3. They play a pivotal role in catalyzing mono- and dimethylation of histone H3 at lysine 36 (H3K36me1/2), a modification critical for maintaining chromatin structure and transcriptional fidelity. Dysregulation of NSD enzymes, often through overexpression, mutation, or chromosomal translocation, has been implicated in a broad spectrum of malignancies and various diseases.
View Article and Find Full Text PDFEMBO J
September 2025
Department of Biology, University of Crete, Vassilika Vouton, Heraklion, 70013, Greece.
In the presence of chromatin bridges in cytokinesis, human cells retain actin-rich structures (actin patches) at the base of the intercellular canal to prevent chromosome breakage. Here, we show that daughter nuclei connected by chromatin bridges are under mechanical tension that requires interaction of the nuclear membrane Sun1/2-Nesprin-2 Linker of Nucleoskeleton and Cytoskeleton (LINC) complex with the actin cytoskeleton, and an intact nuclear lamina. This nuclear tension promotes accumulation of Sun1/2-Nesprin-2 proteins at the base of chromatin bridges and local enrichment of the RhoA-activator PDZ RhoGEF through PDZ-binding to cytoplasmic Nesprin-2 spectrin repeats.
View Article and Find Full Text PDFProtoplasma
September 2025
Vavilov Institute of General Genetics RAS, Moscow, Russia.
Large interstitial telomeric regions are considered remnants and markers of chromosomal rearrangements or a result of several suggested molecular mechanisms of telomere repeats accumulation. More rare are cases when large interstitial repeats are found not close to, but at a distance from the centromere. However, synapsis, recombination, and effects on chromatin near these regions during meiotic prophase I have not been sufficiently studied.
View Article and Find Full Text PDFNat Biotechnol
September 2025
Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, USA.
RNA-protein interactions critically regulate gene expression and cellular processes, yet their comprehensive mapping remains challenging due to their structural diversity. We introduce PRIM-seq (protein-RNA interaction mapping by sequencing), a method for concurrent de novo identification of RNA-binding proteins and their associated RNAs. PRIM-seq generates unique chimeric DNA sequences by proximity ligation of RNAs with protein-linked DNA barcodes, which are subsequently decoded through sequencing.
View Article and Find Full Text PDFCardiovasc Res
September 2025
Center for Cardiovascular Research, Division of Cardiology, Department of Medicine, Washington University in Saint Louis, St. Louis, MO, USA.
Aims: Although the ability of the heart to adapt to environmental stress has been studied extensively, the molecular and cellular mechanisms responsible for cardioprotection are not yet fully understood. In this study, we sought to elucidate these mechanisms for cytoprotection using a model of stress-induced cardiomyopathy.
Methods And Results: We administered Toll-like receptor (TLR) agonists or diluent to wild-type mice and assessed for cardioprotection against injury from a high intraperitoneal dose of isoproterenol (ISO) administered 7 days later.