DNA accessibility to various protein complexes is essential for various processes in the cell and is affected by nucleosome structure and dynamics. Protein factor PARP-1 (poly(ADP-ribose)polymerase 1) increases the accessibility of DNA in chromatin to repair proteins and transcriptional machinery, but the mechanism and extent of this chromatin reorganization are unknown. Here we report on the effects of PARP-1 on single nucleosomes revealed by spFRET (single-particle Förster Resonance Energy Transfer) microscopy. PARP-1 binding to a double-strand break in the vicinity of a nucleosome results in a significant increase of the distance between the adjacent gyres of nucleosomal DNA. This partial uncoiling of the entire nucleosomal DNA occurs without apparent loss of histones and is reversed after poly(ADP)-ribosylation of PARP-1. Thus PARP-1-nucleosome interactions result in reversible, partial uncoiling of the entire nucleosomal DNA.
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http://dx.doi.org/10.3934/genet.2017.1.21 | DOI Listing |
Int J Mol Sci
December 2024
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA.
In eukaryotic nuclei, DNA is wrapped around an octamer of core histones to form nucleosomes. H1 binds to the linker DNA of nucleosome to form the chromatosome, the next structural unit of chromatin. Structural features on individual chromatosomes contribute to chromatin structure, but not fully characterized.
View Article and Find Full Text PDFCureus
December 2024
Nephrology, Unidade Local de Saúde de São José, Lisbon, PRT.
Immunoglobulin G4-related disease (IgG4-RD) and systemic lupus erythematosus (SLE) are multisystemic autoimmune disorders that can present with renal manifestations. Overlapping cases of these diseases are extremely rare and present both diagnostic and therapeutic challenges. We report the case of a 70-year-old male with a history of autoimmune pancreatitis, who was admitted with fatigue, weight loss, and worsening kidney function.
View Article and Find Full Text PDFClin Transl Med
January 2025
BOE Technology Group Co., Ltd, Beijing, China.
Background: Multi-omics features of cell-free DNA (cfDNA) can effectively improve the performance of non-invasive early diagnosis and prognosis of cancer. However, multimodal characterization of cfDNA remains technically challenging.
Methods: We developed a comprehensive multi-omics solution (COMOS) to specifically obtain an extensive fragmentomics landscape, presented by breakpoint characteristics of nucleosomes, CpG islands, DNase clusters and enhancers, besides typical methylation, copy number alteration of cfDNA.
Nat Commun
January 2025
Friedrich Miescher Institute for Biomedical Research, Fabrikstrasse 24, 4056, Basel, Switzerland.
In the germ line and during early embryogenesis, DNA methylation (DNAme) undergoes global erasure and re-establishment to support germ cell and embryonic development. While DNAme acquisition during male germ cell development is essential for setting genomic DNA methylation imprints, other intergenerational roles for paternal DNAme in defining embryonic chromatin are unknown. Through conditional gene deletion of the de novo DNA methyltransferases Dnmt3a and/or Dnmt3b, we observe that DNMT3A primarily safeguards against DNA hypomethylation in undifferentiated spermatogonia, while DNMT3B catalyzes de novo DNAme during spermatogonial differentiation.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Physics and Astronomy and Center for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854, USA.
Nucleosomes are fundamental units of chromatin in which a length of genomic DNA is wrapped around a histone octamer spool in a left-handed superhelix. Large-scale nucleosome maps show a wide distribution of DNA wrapping lengths, which in some cases are tens of base pairs (bp) shorter than the 147 bp canonical wrapping length observed in nucleosome crystal structures. Here, we develop a thermodynamic model that assumes a constant free energy cost of unwrapping a nucleosomal bp.
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