In collaboration with Phoenix Flow Systems, we offer the APO™-BrdU TUNEL Assay Kit which provides all the materials necessary to label and detect the DNA strand breaks of apoptotic cells. When DNA strands are cleaved or nicked by nucleases, a large number of 3´hydroxyl ends are exposed. In the APO-BrdU assay, these ends are labeled with BrdUTP and terminal deoxynucleotidyl transferase (TdT) using the TUNEL technique. Once incorporated ino the DNA, BrdU is detected using a bright and photostable green-fluorescent Alexa Fluor™ 488 dye-labeled anti-BrdU antibody.