A chromatin immunoprecipitation protocol for small cell numbers.

Chromatin immunoprecipitation (ChIP) is a widely used technique to get a snap-shot of protein-DNA interactions in cells. ChIP has notably been used for mapping the location of modified histones, transcription factors, or chromatin remodeling enzymes in the genome, often in relation to transcription or differentiation. Conventional ChIP protocols however, have for a long time required large numbers of cells, which has limited the applicability of ChIP to rare or small cell samples. In recent years, ChIP assays for small cell numbers (in the 10,000-100,000 range) have been recently reported by us and others. This chapter describes a micro (μ)ChIP procedure for multiple parallel ChIPs from a single chromatin batch from 1,000 cells.