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Updated: Jun 6, 2026
Detection and Analysis of DNA Damage in Mouse Skeletal Muscle In Situ Using the TUNEL Method
Published on: December 16, 2014
In situ detection of apoptosis by the TUNEL assay: an overview of techniques
1MacroGenics, Inc, South San Francisco, CA, USA. lood@macrogenics.com
Abstract:
Apoptosis, or programmed cell death, plays an important role in normal development and homeostasis of adult tissues. Apoptosis has also been linked to many disease states, including cancer. One of the biochemical hallmarks of apoptosis is the generation of free 3'-hydroxyl termini on DNA via cleavage of chromatin into single and multiple oligonuleosome-length fragments. The TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay exploits this biochemical hallmark by labeling the exposed termini of DNA, thereby enabling visualization of nuclei containing fragmented DNA. This review outlines the general method for in situ TUNEL staining of cultured cells and tissue sections, and highlights recent improvements in the technique and limitations of the assay.
Insights
The TUNEL assay detects programmed cell death (apoptosis) by labeling fragmented DNA. This review details the TUNEL method for visualizing apoptosis in cells and tissues, including recent advancements and limitations.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Apoptosis, or programmed cell death, is crucial for tissue development and homeostasis.
- Apoptosis is implicated in various diseases, notably cancer.
- DNA fragmentation, generating free 3'-hydroxyl termini, is a hallmark of apoptosis.
Purpose of the Study:
- To review the in situ TUNEL assay for detecting apoptosis.
- To outline the general methodology for TUNEL staining in cultured cells and tissue sections.
- To highlight recent technical improvements and inherent limitations of the TUNEL assay.
Main Methods:
- The TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay.
- Labeling of exposed DNA 3'-hydroxyl termini generated during apoptosis.
- In situ staining of cultured cells and tissue sections for visualization of fragmented DNA.
Main Results:
- The TUNEL assay enables the visualization of apoptotic cells by detecting DNA fragmentation.
- The review covers the standard TUNEL staining protocol.
- Recent advancements and limitations of the TUNEL technique are discussed.
Conclusions:
- The TUNEL assay is a valuable tool for identifying apoptosis.
- Understanding the method's improvements and limitations is key for accurate interpretation.
- This technique aids in studying apoptosis in both normal physiological processes and disease states.
