CUT&Tag is an efficient, high-resolution chromatin protein – DNA interaction analysis technique with extremely low sample input requirements. Its core principle is as follows: first, a specific antibody (such as anti-H3K4me3) is used to bind the target chromatin protein in situ within the nucleus. Subsequently, an engineered hyperactive pA/G – Tn5 transposase pre-loaded with sequencing adapters is introduced, which is anchored to the target site via the affinity between Protein A/G and the antibody. After activation by adding Mg²⁺, the Tn5 precisely cleaves the DNA at the target region and simultaneously inserts adapter sequences, achieving tagmentation. The sequencing library is then constructed through PCR amplification. Compared to traditional ChIP – seq, CUT&Tag offers lower background noise, higher signal to noise ratio, a simpler library preparation workflow, and yields stable, reproducible protein – DNA binding profiles even with extremely low cell numbers, making it particularly suitable for epigenetic studies of low abundance targets such as transcription factors.
