ChIP is a method used to determine where, in vivo, a given protein binds to DNA. The challenge of the ChIP method is the requirement for highly specific antibodies for each protein to be tested. The HaloCHIP System works without the use of antibodies and delivers results in less time than standard ChIP methods (two days versus four days). Signal-to-noise ratios are improved, enabling high sensitivity for the detection of even small changes in protein binding patterns from a reduced number of cells. The HaloCHIP System is based on HaloTag Technology from Promega. The HaloTag reporter protein has been engineered to form a covalent interaction with a series of specific ligands, including one for immobilization, HaloLink Resin. In HaloCHIP, DNA-binding proteins of interest are expressed in cells as HaloTag fusion proteins, crosslinked to DNA with formaldehyde, and then covalently captured on HaloLink Resin. After the captured complexes are rigorously washed to remove any non-specific interactions, crosslinks are reversed, and the specific DNA is released for downstream analysis.