The RAD21 antibody is a crucial tool for studying the RAD21 protein, a core component of the cohesin complex essential for chromosome segregation, DNA repair, and transcriptional regulation. RAD21. along with SMC1. SMC3. and STAG1/2. forms a ring-like structure that mediates sister chromatid cohesion during mitosis and meiosis, ensuring accurate chromosome segregation. Beyond its structural role, RAD21 participates in DNA double-strand break repair via homologous recombination and modulates gene expression by facilitating chromatin loop formation. Dysregulation of RAD21 is linked to cancer (e.g., leukemia, breast cancer), developmental disorders (e.g., Cornelia de Lange syndrome), and other genomic instability-related diseases. RAD21 antibodies, typically generated in hosts like rabbits or mice, are widely used in techniques such as Western blotting, immunofluorescence, ChIP-seq, and flow cytometry to detect RAD21 expression, localization, and interactions. Their specificity is validated through knockout controls or siRNA knockdowns. Researchers also employ these antibodies to explore cohesinopathies, therapeutic targets, and RAD21's role in 3D genome organization. Commercially available variants include monoclonal and polyclonal formats, with reactivity across species like human, mouse, and rat.