Regulation of CTCF loop formation during pancreatic cell differentiation

• Type of Material: Article
• Authors: Xiaowen Lyu, Emory University; M. Jordan Rowley, University of Nebraska, Omaha; Michael J. Kulik, University of Georgia, Athens; Stephen Dalton, University of Georgia, Athens; Victor Corces, Emory University
• Language: English
• Date: 2023-10-09
• Publisher: Springer Nature
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2023
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): https://doi.org/10.1038/s41467-023-41964-6
• Title of Journal or Parent Work: Nature Communications
• Volume: 14
• Start Page: 6314
• Grant/Funding Information: This work was supported by U.S. Public Health Service Awards R35 GM139408 (VGC), R00 GM127671 and R35 GM147467 (MJR), and 5P01 GM085354 (SD) from the National Institutes of Health.
• Keywords: Epigenomics; Chromatin structure
• Research Categories: Biology, Cell; Biology, Genetics; Biology, Molecular

Abstract

Transcription reprogramming during cell differentiation involves targeting enhancers to genes responsible for establishment of cell fates. To understand the contribution of CTCF-mediated chromatin organization to cell lineage commitment, we analyzed 3D chromatin architecture during the differentiation of human embryonic stem cells into pancreatic islet organoids. We find that CTCF loops are formed and disassembled at different stages of the differentiation process by either recruitment of CTCF to new anchor sites or use of pre-existing sites not previously involved in loop formation. Recruitment of CTCF to new sites in the genome involves demethylation of H3K9me3 to H3K9me2, demethylation of DNA, recruitment of pioneer factors, and positioning of nucleosomes flanking the new CTCF sites. Existing CTCF sites not involved in loop formation become functional loop anchors via the establishment of new cohesin loading sites containing NIPBL and YY1 at sites between the new anchors. In both cases, formation of new CTCF loops leads to strengthening of enhancer promoter interactions and increased transcription of genes adjacent to loop anchors. These results suggest an important role for CTCF and cohesin in controlling gene expression during cell differentiation.