title: GSM9684976: MDA-MB-231 cells, TRIM27-KO, CTD, rep1, batch2; Homo sapiens; OTHER
library_construction_protocol: Genomic chromatin was extracted from intact MDA-MB-231 human breast cancer cells using native nuclear isolation conditions suitable for CUT&Tag. No cross-linking (fixation) was performed. Crude nuclei were isolated gently and used directly for the CUT&Tag reaction without further fragmentation, in accordance with the Hyperactive Universal CUT&Tag Assay Kit for Illumina (Vazyme, TD903) protocol. Libraries were prepared using the Hyperactive Universal CUT&Tag Assay Kit for Illumina (Vazyme, TD903) following the manufacturer's instructions. Briefly, intact nuclei were isolated and incubated with primary antibodies targeting TRIM27, CTD, p-CTD-S2, or IgG control. Protein A/G-tn5 transposase was then added to bind the antibodies and fragment chromatin. Library fragments were enriched by PCR amplification and purified using magnetic beads. Final libraries were quantified and subjected to high-throughput sequencing on the MGISEQ-2000 platform.