A ChIP on the shoulder? Chromatin immunoprecipitation and validation strategies for ChIP antibodies

Chromatin immunoprecipitation (ChIP) is a technique widely used in the study of epigenetics and transcriptional regulation of gene expression. However, its antibody-centric nature exposes it to similar challenges faced by other antibody-based procedures, of which the most prominent are issues of specificity and affinity in antigen recognition. As with other techniques that make use of antibodies, recent studies have shown the need for validation of ChIP antibodies in order to be sure they recognize the advertised protein or epitope. We summarize here the issues surrounding ChIP antibody usage, and highlight the toolkit of validation methods that can be employed by investigators looking to appraise these reagents.