CTCF coordinates cell fate specification via orchestrating regulatory hubs with pioneer transcription factors
CCCTC-binding factor (CTCF), a ubiquitously expressed architectural protein, has emerged as a key regulator of cell identity gene transcription. However, the precise molecular mechanism underlying specialized functions of CTCF remains elusive. Here, we investigate the mechanism through integrative analyses of primary hepatocytes, myocytes, and B cells from mouse and human. We demonstrate that CTCF cooperates with lineage-specific pioneer transcription factors (TFs), including MyoD, FOXA, and PU.1, to control cell identity at 1D and 3D levels. At the 1D level, pioneer TFs facilitate lineage-specific CTCF occupancy via opening chromatin. At the 3D level, CTCF and pioneer TFs form regulatory hubs to govern the expression of cell identity genes. This mechanism is validated using MyoD-null mice, CTCF knockout mice, and CRISPR editing during myogenic differentiation. Collectively, these findings uncover a general mechanism whereby CTCF acts as a cell identity cofactor to control cell identity genes via orchestrating regulatory hubs with pioneer TFs. Overall design: RNA-seq for C2C12 cell lines with and without CTCF knockdown. ATAC-seq for myoblast and myocyte from wild type and MyoD-null mice.