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Enhancer-promoter interactions occur in the chromatin loci delineated by the CCCTC-binding zinc-finger protein CTCF. CTCF binding is frequently perturbed in genetic disorders and cancer, allowing for misregulation of genes. Here, we developed a panel of chimeric proteins consisting of either full-length or truncated CTCF fused with programmable DNA-binding module dCas9 and fluorescent tracker EGFP. We found that the recruitment of a chimeric protein based on the CTCF N-terminal domain and two zinc-finger domains to the human locus leads to the de novo formation of a spatial contact with a nearby cohesin/CTCF-bound region, anchoring several chromatin loops. This chimeric protein did not show binding to CTCF motifs and did not affect the epigenetic and transcription profile of the locus. Recruitment of this chimeric protein is also able to restore chromatin loops, lost after deletion of an endogenous CTCF-binding site. Together, our data indicate that the ectopic recruitment of the CTCF N-terminal part could be an appropriate tool for 3D genome engineering.
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http://dx.doi.org/10.3390/ijms26157446 | DOI Listing |
Int J Mol Sci
August 2025
Institute of Gene Biology, Moscow 119334, Russia.
Enhancer-promoter interactions occur in the chromatin loci delineated by the CCCTC-binding zinc-finger protein CTCF. CTCF binding is frequently perturbed in genetic disorders and cancer, allowing for misregulation of genes. Here, we developed a panel of chimeric proteins consisting of either full-length or truncated CTCF fused with programmable DNA-binding module dCas9 and fluorescent tracker EGFP.
View Article and Find Full Text PDFGenes Dev
August 2025
Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA;
We report here on the identification of a previously unrecognized property of MYOD as a repressor of gene expression via E-box-independent chromatin binding during the process of somatic cell -differentiation into skeletal muscle. When ectopically expressed in proliferating human fibroblasts or endogenously induced in activated muscle stem cells (MuSCs), MYOD was detected at accessible regulatory elements of expressed genes, invariably leading to reduced chromatin accessibility and gene repression. At variance with conventional E-box-driven increased chromatin accessibility and H3K27 acetylation at previously silent loci of MYOD-activated genes, MYOD-mediated chromatin compaction and repression of transcription was associated with high occurrence of non-E-box motifs and did not lead to reduced levels of H3K27ac but coincided with reduced levels of H4 acetyl-methyl lysine modification (Kacme).
View Article and Find Full Text PDFNucleic Acids Res
June 2025
Molecular Pathology Section, Laboratory of Immunogenetics, Division of Intramural Research/National Institute of Allergy and Infectious Diseases (NIAID)/ National Institutes of Health (NIH), Bethesda, MD 20892, United States.
CTCF binding sites serve as anchors for the 3D chromatin architecture in vertebrates. The functionality of these anchors is influenced by the residence time of CTCF on chromatin, which is determined by its binding affinity and its interactions with nucleosomes and other chromatin-associated factors. In this study, we demonstrate that CTCF occupancy is driven by CTCF motifs, strategically positioned at the entry sides of a well-positioned nucleosome, such that, upon binding, the N-terminus of CTCF is oriented towards the nucleosome.
View Article and Find Full Text PDFJ Biol Chem
April 2025
Center for Comparative Biomedicine, Ministry of Education Key Laboratory of Systems Biomedicine, State Key Laboratory of Medical Genomics, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China. Electronic address:
CTCF (CCCTC-binding factor) instructs 3D genome folding by anchoring or forestalling cohesin loop extrusion, but the exact mechanism remains obscure. Here, using clustered protocadherins (cPcdh) as model genes, we report that CTCF assists or facilitates cohesin loop extrusion by enhancing its processivity. Specifically, we show that, compared with the Pcdh α and γ gene clusters, the Pcdhβ cluster is greatly affected upon CTCF mutation in the N-terminal domain.
View Article and Find Full Text PDFbioRxiv
December 2024
Sanford Burnham Prebys Medical Discovery Institute, Development, Aging and Regeneration Program, La Jolla, CA.
MYOD is an E-box sequence-specific basic Helix-Loop-Helix (bHLH) transcriptional activator that, when expressed in non-muscle cells, induces nuclear reprogramming toward skeletal myogenesis by promoting chromatin accessibility at previously silent loci. Here, we report on the identification of a previously unrecognized property of MYOD as repressor of gene expression, via E-box-independent chromatin binding within accessible genomic elements, which invariably leads to reduced chromatin accessibility. MYOD-mediated repression requires the integrity of functional domains previously implicated in MYOD-mediated activation of gene expression.
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