Nucleosome movement is, at least in part, facilitated by ISWI ATPase Smarca5 (Snf2h). Smarca5 gene inactivation in mouse demonstrated its requirement at blastocyst stage; however its role at later stages is not completely understood. We herein determined nuclear distribution of Smarca5 and histone marks associated with actively transcribed and repressed chromatin structure in embryonic and adult murine tissues and in tumor cells. Confocal microscopy images demonstrate that Smarca5 is localized mainly in euchromatin and to lesser extent also in heterochromatin and nucleoli. Smarca5 heterozygous mice for a null allele display decreased levels of histone H3 modifications and defects in heterochromatin foci supporting role of Smarca5 as a key regulator of global chromatin structure.
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http://dx.doi.org/10.2741/e53 | DOI Listing |
bioRxiv
January 2025
Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA.
Chromatin remodeling enzymes play a crucial role in the organization of chromatin, enabling both stability and plasticity of genome regulation. These enzymes use a Snf2-type ATPase motor to move nucleosomes, but how they translocate DNA around the histone octamer is unclear. Here we use cryo-EM to visualize the continuous motion of nucleosomal DNA induced by human chromatin remodeler SNF2H, an ISWI family member.
View Article and Find Full Text PDFNat Commun
January 2025
Institute for Cancer Genetics, Department of Pediatrics and Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, 10032, USA.
Following DNA replication, the newly reassembled chromatin is disorganized and must mature to its steady state to maintain both genome and epigenome integrity. However, the regulatory mechanisms governing this critical process remain poorly understood. Here, we show that histone H3K56 acetylation (H3K56ac), a mark on newly-synthesized H3, facilitates the remodeling of disorganized nucleosomes in nascent chromatin, and its removal at the subsequent G2/M phase of the cell cycle marks the completion of chromatin maturation.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Adenosin triphosphate (ATP)-dependent nucleosome remodeling factors sculpt the nucleosomal landscape of eukaryotic chromatin. They deposit, evict, or reposition nucleosomes along DNA in a process termed nucleosome sliding. Remodeling has traditionally been analyzed using mononucleosomes as a model substrate.
View Article and Find Full Text PDFZhonghua Yi Xue Yi Chuan Xue Za Zhi
November 2024
Shanghai Key Laboratory of Embryo Original Diseases, the CWI International Peace Maternity and Child Health Care Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China.
ATP-dependent chromatin remodeling complexes play crucial roles in various biological processes including enhancing local DNA accessibility, regulating gene transcription, and facilitating DNA replication and repair. Based on their functional structural domains, these complexes may be categorized into four families, including SWI/SNF, ISWI, CHD and INO80. Such families are vital factors for regulating gene expression and play pivotal roles in developmental processes.
View Article and Find Full Text PDFNucleic Acids Res
November 2024
Department of Molecular Biosciences, University of South Florida, Tampa, FL 33620, USA.
Nucleosome remodelers at replication forks function in the assembly and maturation of chromatin post DNA synthesis. The ISWI chromatin remodeler SNF2L (or SMARCA1) travels with replication forks but its contribution to DNA replication remains largely unknown. We find that fork elongation is curtailed when SNF2L is absent.
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