Fig. 1.

Illustration of chromatin enrichment using chromatin immunoprecipitation (ChIP)-like methods. A: modified chromatin immunopurification (mChIP) uses histones with tandem affinity purification (TAP) tags to enrich local chromatin fragments. DNA shearing can be accomplished mechanically through sonication or enzymatically through micrococcal nuclease or DNase I digestion. B: chromatin-interacting protein in mass spectrometry (ChIP-MS). HTB-tags capable of undergoing endogenous biotinylation are attached to a target DNA-binding protein and used to capture a chromatin fragment by using streptavidin-coated magnetic beads. C: chromatin proteomics (ChroP). Nontreated chromatin can be sheared through micrococcal nuclease digestion, or cross-linked chromatin can be mechanically sheared through sonication. Chromatin fragments are enriched with antibodies against trimethylated histone variants.