Development of nucleus-targeted synthetic histone photoaffinity probes

Dissection of the physiological interactomes of histone post-translational modifications (hPTMs) is crucial for understanding fundamental epigenetic regulatory pathways. Current peptide- or protein-based histone photoaffinity probes have greatly expanded the ability to probe the epigenetic interactome, but in situ profiling in the context of native cells (live cells without genetic manipulations) remains challenging. Here, we developed a nucleus-targeted histone photoaffinity probe with a modular design that integrates a cell-permeable and nuclear localization peptide modules into an hPTM peptide equipped with a photoreactive moiety for profiling the hPTM-mediated interactome in native cells. This probe not only enables the probing of epigenetic interactomes in hard-to-transfect macrophage RAW264.7 cells, but also offers opportunities to characterize the interactome of newly emerging hPTM, such as lactylation, thus expanding the toolbox for profiling of hPTM-mediated PPIs in live cells.