CCCTC-binding factor (CTCF) critically contributes to 3D chromatin organization by determining topologically associated domain (TAD) borders. Although CTCF primarily binds at TAD borders, there also exist putative CTCF-binding sites within TADs, which are spread throughout the genome by retrotransposition. However, the detailed mechanism responsible for masking the putative CTCF-binding sites remains largely elusive. Here, we show that the ATP-dependent chromatin remodeler, chromodomain helicase DNA-binding 4 (CHD4), regulates chromatin accessibility to conceal aberrant CTCF-binding sites embedded in H3K9me3-enriched heterochromatic B2 short interspersed nuclear elements (SINEs) in mouse embryonic stem cells (mESCs). Upon CHD4 depletion, these aberrant CTCF-binding sites become accessible and aberrant CTCF recruitment occurs within TADs, resulting in disorganization of local TADs. RNA-binding intrinsically disordered domains (IDRs) of CHD4 are required to prevent this aberrant CTCF binding, and CHD4 is critical for the repression of B2 SINE transcripts. These results collectively reveal that a CHD4-mediated mechanism ensures appropriate CTCF binding and associated TAD organization in mESCs.
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http://dx.doi.org/10.14348/molcells.2021.0224 | DOI Listing |
Sci Rep
December 2024
School of Physical Science and Technology, Inner Mongolia University, Hohhot, 010021, People's Republic of China.
The CCCTC-binding factor (CTCF) is pivotal in orchestrating diverse biological functions across the human genome, yet the mechanisms driving its cell type-active DNA binding affinity remain underexplored. Here, we collected ChIP-seq data from 67 cell lines in ENCODE, constructed a unique dataset of cell type-active CTCF binding sites (CBS), and trained convolutional neural networks (CNN) to dissect the patterns of CTCF binding activity. Our analysis reveals that transcription factors RAD21/SMC3 and chromatin accessibility are more predictive compared to sequence motifs and histone modifications.
View Article and Find Full Text PDFCommun Biol
December 2024
Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga, 849-8501, Japan.
Beckwith-Wiedemann syndrome (BWS) is caused by a gain of methylation (GOM) at the imprinting control region within the Igf2-H19 domain on the maternal allele (H19-ICR GOM). Mutations in the binding sites of several transcription factors are involved in H19-ICR GOM and BWS. However, the responsible sequence(s) for H19-ICR GOM with BWS-like overgrowth has not been identified in mice.
View Article and Find Full Text PDFMol Cell
December 2024
Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Electronic address:
Cell
November 2024
Gladstone Institute for Data Science & Biotechnology, San Francisco, CA 94158, USA; UCSF Department of Biochemistry & Biophysics, San Francisco, CA 94158, USA; Helen Diller Cancer Research Center, UCSF, San Francisco, CA 94158, USA; Bakar Computational Health Sciences Institute, UCSF, San Francisco, CA 94158, USA. Electronic address:
We present replication-aware single-molecule accessibility mapping (RASAM), a method to nondestructively measure replication status and protein-DNA interactions on chromatin genome-wide. Using RASAM, we uncover a genome-wide state of single-molecule "hyperaccessibility" post-replication that resolves over several hours. Combining RASAM with cellular models for rapid protein degradation, we demonstrate that histone chaperone CAF-1 reduces nascent chromatin accessibility by filling single-molecular "gaps" and generating closely spaced dinucleosomes on replicated DNA.
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