Elucidating the physiological binding partners of histone post-translational modifications (hPTMs) is key to understanding fundamental epigenetic regulatory pathways. Determining such interactomes will enable the study of how perturbations of these interactions affect disease. Here we use a synthetic biology approach to set a series of hPTM-controlled photo-affinity traps in native chromatin. Using quantitative proteomics, the local interactomes of these chemically customized chromatin landscapes are determined. We show that the approach captures transiently interacting factors such as methyltransferases and demethylases, as well as previously reported and novel hPTM reader proteins. We also apply this in situ proteomics approach to a recently disclosed cancer-associated histone mutation, H3K4M, revealing a number of perturbed interactions with the mutated tail. Collectively our studies demonstrate that modifying and interrogating native chromatin with chemical precision is a powerful tool for exploring epigenetic regulation and dysregulation at the molecular level.

阐明组蛋白翻译后修饰 (hPTM) 的生理结合伙伴是了解基本表观遗传调控途径的关键。确定这种相互作用组将使研究这些相互作用的扰动如何影响疾病成为可能。在这里，我们使用合成生物学方法在天然染色质中设置一系列 hPTM 控制的光亲和陷阱。使用定量蛋白质组学，确定这些化学定制染色质景观的局部相互作用组。我们表明，该方法捕获了瞬时相互作用的因子，例如甲基转移酶和去甲基化酶，以及先前报道的新型 hPTM 阅读器蛋白。我们还将这种原位蛋白质组学方法应用于最近披露的癌症相关组蛋白突变 H3K4M，揭示了与变异尾巴的许多扰动相互作用。总的来说，我们的研究表明，以化学精度修饰和询问天然染色质是在分子水平上探索表观遗传调控和失调的有力工具。