coimmunoprecipitation chromatin immunoprecipitation assay MI:0402 PSI-MI ch-ip Chromatin immunoprecipitation (ChIP) is a powerful approach that allows one to define the interaction of factors with specific chromosomal sites in living cells. An antibody against a protein suspected of binding a given cis-element is used to immunoprecipitate fragmented chromatin fragments. Cells or tissue may first be briefly treated with an agent such formaldehyde to crosslink proteins to DNA. Nucleic acids are then identified by sequencing, for example polymerase chain reaction analysis of the immunoprecipitate with primers flanking the cis-element or next-generation sequencing techniques