CTCF
CTCF (CCCTC-binding factor, also known as FAP108 and CFAP108) is an 11-zinc-finger nuclear protein that binds DNA at specific sites and shapes the three-dimensional structure of chromatin. It acts as an insulator, a loop-forming anchor and a context-dependent transcriptional regulator. Browse Assay Genie's current range of CTCF research reagents below, or read on for the biology behind the target.
CTCF is a chromatin binding factor that recognises sequence-specific DNA sites and regulates chromatin architecture. It can bind together strands of DNA to form chromatin loops, and it anchors DNA to cellular structures such as the nuclear lamina. By binding chromatin insulators, it defines the boundaries between active and heterochromatic DNA and prevents promoters from interacting with nearby enhancers and silencers. The protein can dimerise when bound to different DNA sequences, which mediates long-range looping, and it provides an anchor point for nucleosome positioning.
The CTCF gene belongs to the BORIS + CTCF family, and the protein belongs to the CTCF zinc-finger protein family. It contains 11 highly conserved C2H2-type zinc finger domains, and different combinations of these domains bind different DNA targets and proteins. Depending on context, CTCF can recruit a histone acetyltransferase-containing complex and act as an activator, or a histone deacetylase-containing complex and act as a repressor. It binds the MYC and BAG1 promoters as a repressor and activates APP. It preferentially binds unmethylated DNA, helping to maintain methylation-free zones, while CpG methylation prevents its binding. Alternatively spliced transcript variants encode different isoforms.
CTCF participates in allele-specific expression at the imprinted IGF2/H19 locus, where binding in the H19 imprinting control region restricts enhancer access to IGF2 on the maternal allele. It is also implicated in X-chromosome pairing and inactivation, sister chromatid cohesion, cohesin localisation to CTCF sites, and CENPE recruitment to centromeric regions in mitosis. It is essential for oocyte and preimplantation embryo development and appears to act as a tumour suppressor. Mutations have been associated with invasive breast cancer, prostate cancer and Wilms' tumour. Mouse and rat orthologues are both named Ctcf.
CTCF forms chromatin loops, anchors DNA to the nuclear lamina and marks boundaries between active and heterochromatic regions.
CTCF binding at the H19 imprinting control region regulates allele-specific IGF2/H19 expression, and its binding is blocked by CpG methylation.
CTCF contributes to sister chromatid cohesion, cohesin localisation and CENPE recruitment to centromeric regions during mitosis.
CTCF appears to act as a tumour suppressor, and mutations are linked to breast cancer, prostate cancer and Wilms' tumour.
CTCF binds specific DNA sites and organises chromatin in three dimensions. It forms loops, acts at insulators to block enhancer-promoter contact, and can activate or repress transcription depending on the complexes it recruits. It also supports imprinting, X-chromosome pairing and sister chromatid cohesion.
CTCF stands for CCCTC-binding factor, formerly CCCTC-binding factor (zinc finger protein). Aliases are FAP108 and CFAP108, and UniProt lists it as transcriptional repressor CTCF. Alternatively spliced transcript variants encoding different isoforms have been reported for the CTCF gene.
CTCF has orthologues named Ctcf in mouse and rat, and its 11 zinc finger domains are highly conserved. Mutations are associated with invasive breast cancer, prostate cancer and Wilms' tumour; check the datasheet of any product for its validated reactivity.
CTCFL, the BORIS paralogue within the same gene family, is the closest related target with a page at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P49711; product specifications from Assay Genie datasheets.