Fig. 4

a Outline of chromatin immunoprecipitation (ChIP) assays, site-specific analysis or native ChIP (NChIP) and other improved ChIP assays (fast and μ or macro ChIP. In summary, the fixation/crosslinking step is an essential step in the ChIP protocol which is removed by the enzymatic method. After nuclei purification from tissues or cultured cells, chromatin is fractionated with enzymatic or no enzymatic treatments. Then, purified nucleosomes incubated with antiserum are directed against the histone modification of interest. Subsequently, detection is performed by PCR/quantitative PCR (QPCR) technologies. b Outline of matrix chromatin immunoprecipitation (Matrix ChIP) assays; Matrix ChIP is an improved version of the classic ChIP assay. Surface-immobilized antibodies in 96-well plates are used. The assay has enhanced antibody binding capacity and minimal sampling for detection of low- and high-affinity proteins in only 1 day