CTCFbinding

CTCF binding refers to the interaction of the CCCTC-binding factor (CTCF) protein with specific DNA sequences. CTCF is a highly conserved, multi-domain zinc-finger protein that plays a crucial role in genome organization and regulation. It is known to bind to over 20,000 predicted sites across the mammalian genome, acting as a major architectural protein. These binding sites are often found at the boundaries of topologically associating domains (TADs), which are self-interacting regions of the genome. CTCF binding is essential for establishing and maintaining these TAD structures, thereby influencing gene expression by compartmentalizing regulatory elements from target genes. Furthermore, CTCF can act as an insulator element, preventing enhancers from activating inappropriate promoters. It also plays a role in X-chromosome inactivation and imprinting. The specific DNA sequences recognized by CTCF are degenerate, meaning they can vary, but they typically contain a core consensus motif. The precise positioning and orientation of CTCF binding sites are critical for its diverse regulatory functions.