Transcriptional repressor CTCF (also known as CCCTC-binding factor) is a transcription factor encoded by the CTCF gene. The CTCF, and the closely related Brother of the Regulator of Imprinted Sites (BORIS), are highly conserved zinc finger proteins implicated in diverse regulatory functions, including transcriptional activation/repression, insulation, imprinting, and X chromosome inactivation. Expression of BORIS is restricted to spermatocytes and is mutually exclusive of CTCF expression. CTCF is ubiquitously expressed in higher eukaryotes and contains a highly conserved and eleven zinc finger central DNA-binding domain, having very high homology between mouse, chicken, and human and is embedded within slightly divergent N and C termini. CTFC plays a critical role in the epigenetic regulation and chromatin remodeling. CTCF has been reported to bind to a variety of DNA target sites that perform distinct functions, including promoter activation or repression, hormone-responsive gene silencing, methylation-dependent chromatin insulation, and genomic imprinting.
CTCF affinity purified antibody was prepared by repeated immunizations with a synthetic peptide corresponding to a region near the C-terminus of CTCF protein.