Af-CUT&Tag: A Sensitive and Antibody-Free Chromatin Profiling Method Using Genetically Encoded Tags and High-Affinity Binders Fused to Tn5

Conventional chromatin profiling techniques are often limited by antibody availability and performance. Here, we introduce Af-CUT&Tag, a target antibody-free method that overcomes these limitations by using CRISPR-integrated peptide tags (HiBiT/ALFA-tag) recognized by engineered binders (LgBiT/NbALFA) fused to a Tn5 transposase. Af-CUT&Tag eliminates dependence on traditional target antibodies, achieving robust specificity and sensitivity with as few as 500 cells. It provides high-quality chromatin profiles, with improved signal-to-noise ratios and library quality compared with conventional antibody-based counterparts, while also enabling single-cell resolution (scAf-CUT&Tag). Applying Af-CUT&Tag to Hippo effectors (YAP1/TAZ) during liver regeneration revealed dynamic chromatin remodeling, including YAP1/TAZ-mediated control of lipid metabolism (e.g., Lpin1, Fasn) and heme clearance (Hpx, Trf). We further identify miR-122 as a critical regulator of these processes, impacting liver regeneration. The versatility of Af-CUT&Tag in cell lines, bulk tissues, and single nuclei establishes it as a powerful tool for studying gene regulation in development, disease, and regeneration. Keywords: Antibody-Free CUT&Tag; Chromatin Binding; Epigenetic Profiling; Peptide-binder; Single-cell analysis