CTCF Protein, Human

CTCF protein is a chromatin-binding factor with diverse roles in transcriptional regulation and epigenetic control. It binds to DNA sequence-specific sites, functioning as a transcriptional repressor by interacting with chromatin insulators, preventing undesired interactions between promoters and nearby enhancers or silencers. Notably, it represses the promoters of genes like MYC and BAG1, while activating transcription of APP. CTCF regulates the APOA1/C3/A4/A5 gene cluster, controls MHC class II gene expression, and plays a crucial role in oocyte and preimplantation embryo development. Functioning as a tumor suppressor, CTCF participates in allele-specific gene expression at the imprinted IGF2/H19 gene locus and is involved in gene silencing over considerable genomic distances. It preferentially interacts with unmethylated DNA, preventing CpG methylation spreading and maintaining methylation-free zones. CTCF is essential for chromatin remodeling, dimerizing when bound to different DNA sequences to mediate long-range chromatin looping. It anchors nucleosomes, influences X-chromosome pairing, and contributes to the regulatable epigenetic switch for X chromosome inactivation. Furthermore, CTCF associates with centromeres and chromosomal arms during metaphase, contributing to sister chromatid cohesion and recruiting CENPE to pericentromeric/centromeric regions during mitosis. Its interaction with CHD8 and LLPH, along with its multifaceted regulatory functions, underscores the critical role of CTCF in the intricate landscape of chromatin organization and gene expression.