What is a CTCF protein?

Our bodies are made of trillions of cells. Each of those cells contain DNA, and different parts of DNA that code for different proteins are called genes. You can think of this coding information as instructions for our bodies. They tell our bodies how to work. When the instructions in our genes are being translated into proteins that help our bodies, they need help from other proteins. CCCTC-binding factor, or CTCF, is one of these proteins. It has many jobs. It is a large protein that helps mediate different roles that help with the expression of a gene.

Here is some more specific information about the CTCF protein:

• CCCTC-binding factor (CTCF) is an architectural protein that can mediate both interchromosomal and intrachromosomal interactions.

• The functional outcomes of these interactions depend on the nature of the sequences adjacent to CTCF-binding sites and perhaps on the presence of other chromatin proteins.

• CTCF-mediated chromatin loops regulate diverse nuclear processes, including V(D)J recombination, enhancer–promoter interactions, transcriptional pausing and alternative mRNA splicing.

• The consensus sequence of CTCF-binding sites is highly conserved. Its variable DNA occupancy pattern is regulated by DNA methylation, non-coding RNAs and post-translational modification.

• CTCF and other architectural proteins, such as cohesin and TFIIIC, maintain genome organization by clustering at the boundaries of megabase-scale topologically associating domains.

• Cell-type-specific chromatin organization occurs at the sub-megabase scale; CTCF, either alone or in combination with other proteins, regulates specific transcriptional processes.

Resource: Ong, CT., Corces, V. CTCF: an architectural protein bridging genome topology and function. Nat Rev Genet 15, 234–246 (2014). https://doi.org/10.1038/nrg3663