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DNA Fragmentation and Morphology


The later stages of apoptosis are characterized by changes in nuclear morphology, including DNA fragmentation, chromatin condensation, degradation of nuclear envelope, nuclear blebbing, and DNA strand breaks. DNA fragmentation that occurs during apoptosis produces DNA strand breaks, which can be analyzed using TUNEL (terminal deoxynucleotidyl transferase dUTP nick end-labeling) assays. TUNEL assays can be used to study cultured cells and tissue sections, including FFPE-treated samples.

In our TUNEL assays, the DNA strand breaks with 3’-hydroxyl ends are labeled with biotin-11-dUTP in the presence of terminal deoxynucleotidyl transferase (TdT). Once incorporated into the DNA, Biotin is detected using HRP or fluorophore labeled streptavidin. Our kits provide sufficient reagents for 50 assays, and are suitable for cell and tissue samples.






  • Broad application: Suitable for FFPE tissue, frozen tissue and cells.
  • High sensitivity:Can detect a low population of apoptotic cells.
  • Multicolor: Many fluorophores to choose.

Table 1. Selection Guide for TUNEL Assay Kit

Cat. No. Product Name Ex/Em (nm) Unit
A049 TUNEL Chromogenic Apoptosis Detection Kit 50 assays
A050 TUNEL Andy Fluor™ 488 Apoptosis Detection Kit 495/520 50 assays
A051 TUNEL Andy Fluor™ 594 Apoptosis Detection Kit 590/615 50 assays
A052 TUNEL Andy Fluor™ 647 Apoptosis Detection Kit 650/665 50 assays

Figure 1. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-mediated detection of apoptotic cells in mouse tongue tissue. The imaging results using TUNEL Andy Fluor™ 488 Apoptosis Detection Kit (left), and TUNEL Chromogenic Apoptosis Detection Kit (right).