DNA Fragmentation & Morphology

Cells undergoing apoptosis display an increase in nuclear chromatin condensation, which is visible using NucBlue™ Live Cell Stain. Nuclear staining works for live or fixed cells and is readily combined with other detection procedures. 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 using Click-iT™ Plus technology can be used to study cultured cells and tissue sections, including FFPE-treated samples.

• DNA stain to visualize chromatin condensation
• TUNEL assays for imaging and HCS
• TUNEL assays for tissue analysis

Endothelial cells stained with NucBlue Live ReadyProbes™ Reagent

For cultured cells, the Click-iT TUNEL Alexa Fluor™ Imaging Assays are optimized for HCS or microscope imaging. The small and specific labeling moiety enables a fast and efficient experimental protocol. The assay is complete within 2 hours, and provides efficient discrimination of even high levels of apoptotic cells in a population. With a choice of fluorescent labels, the Click-iT TUNEL assay allows multiplexing with surface and intracellular biomarker detection.

• Optimized for HCS
• Efficient labeling protocol
• Assay complete in 2 hours
• Three wavelength options for multiplexing

HeLa cells were treated with staurosporine to induce apoptosis and stained using the Click-iT TUNEL Alexa Fluor 594 Imaging Assay, for Microscopy & HCS and Hoechst 33342. Images were acquired using a Thermo Scientific™ ArrayScan™ VTI.

The TUNEL assay is the most widely used method to detect DNA fragmented in apoptotic cells in tissue samples. Using a small labeling moiety and a bright fluorescent dye, Click-iT Plus TUNEL assays have been demonstrated to detect apoptotic cells in several different FFPE (formalin-fixed, paraffin-embedded) tissue types. After the labeling moiety is incorporated into DNA fragments, detection is achieved through a “click” reaction using conditions mild enough to preserve the fluorescent signal from GFP or RFP and maintaining the ability to stain actin using fluorescently labeled phalloidin.

• Optimized for tissue sections
• Small labeling moiety for better penetration
• Three wavelength options for multiplexing
• Mild reaction, compatible with GFP and RFP

The Click-iT Plus TUNEL assay generates a bright, photostable fluorescent signal in a choice of emission colors for multiplexing fluorescent dyes or proteins to enable a variety of experimental conditions.

FFPE sections of mouse intestine expressing GFP in epithelial cells were stained for apoptosis using the Click-iT Plus TUNEL Assay with Alexa Fluor 647. Alexa Fluor 555 Phalloidin was used to stain actin, and nuclei were stained with NucBlue Live ReadyProbes™ Reagent.