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Updated: Aug 29, 2026

HOX Loci Focused CRISPR/sgRNA Library Screening Identifying Critical CTCF Boundaries
Published on: March 31, 2019
CTCF tethers an insulator to subnuclear sites, suggesting shared insulator mechanisms across species
Timur M Yusufzai1, Hideaki Tagami, Yoshihiro Nakatani
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Abstract:
Insulators can block an enhancer of one gene from activating a promoter on another nearby gene. Almost all described vertebrate insulators require binding of the regulatory protein CTCF for their activity. We show that CTCF copurifies with the nucleolar protein nucleophosmin and both are present at insulator sites in vivo. Furthermore, exogenous insulator sequences are tethered to the nucleolus in a CTCF-dependent manner. These interactions, quite different from those of the gypsy insulator element in Drosophila, may generate similar loop structures, suggesting a common theme and model for enhancer-blocking insulator action.
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