Comparative analyses of ChIP-seq, CUT&RUN and CUT&Tag for Polycomb chromatin profiling

Chromatin profiling methods such as ChIP-seq, CUT&RUN, and CUT&Tag differ substantially in background structure, signal distribution, and resolution, complicating direct quantitative comparison across platforms. In this study, we systematically compared conventional and double-crosslink ChIP-seq, CUT&RUN, and CUT&Tag by profiling the Polycomb-associated histone modification H3K27me3 in human cardiomyocytes and the PRC2 catalytic subunit EZH2 in pluripotent stem cells. To enable cross-assay comparison, we developed a biologically informed normalization strategy based on stable Polycomb reference loci, allowing harmonization of signal scales while preserving assay-intrinsic signal architecture. This approach revealed that CUT&RUN preferentially captures broad H3K27me3 domains, whereas CUT&Tag provides sharper and more localized enrichment for both H3K27me3 and EZH2. Together, our results establish a practical framework for cross-platform epigenomic comparison and guide the selection of chromatin profiling strategies. This GEO submission includes only datasets newly generated in this study. Additional publicly available datasets analyzed for comparison are cited in the associated manuscript and were not re-submitted here.