Chromatin biochemistry enters the next generation of code 'seq-ing'

Elucidating the molecular details of how chromatin-associated factors deposit, remove and recognize histone post-translational modification (PTM) signatures remains a daunting task in the epigenetics field. We introduce a versatile platform that greatly accelerates biochemical investigations into chromatin recognition and signaling. This technology is based on the streamlined semisynthesis of DNA-barcoded nucleosome libraries with distinct combinations of PTMs. Chromatin immunoprecipitation of these libraries, once they have been treated with purified chromatin effectors or the combined chromatin recognizing and modifying activities of the nuclear proteome, is followed by multiplexed DNA-barcode sequencing. This ultrasensitive workflow allowed us to collect thousands of biochemical data points revealing the binding preferences of various nuclear factors for PTM patterns and how preexisting PTMs, alone or synergistically, affect further PTM deposition via cross-talk mechanisms. We anticipate that the high throughput and sensitivity of the technology will help accelerate the decryption of the diverse molecular controls that operate at the level of chromatin.