digoxigenin

Digoxigenin, commonly abbreviated as DIG, is the aglycone of the cardiac glycoside digoxin, derived from Digitalis plants. It is a steroidal molecule that functions as a hapten in molecular biology, enabling the generation of specific antibodies used to detect labeled nucleic acids.

In research workflows, digoxigenin is covalently attached to nucleotides or incorporated during nucleic acid synthesis to produce DIG-labeled probes and tags. Commonly used reagents include DIG-labeled nucleotides (for example DIG-UTP or DIG-dUTP) employed in nick-translation, random priming, or PCR-based labeling. The DIG label allows non-radioactive detection, offering a safer alternative to radioisotopes.

Detection relies on anti-digoxigenin antibodies, typically conjugated to enzymes such as alkaline phosphatase or horseradish peroxidase. After binding to the DIG label, colorimetric, chemiluminescent, or fluorescent substrates enable visualization of the labeled nucleic acids. The technique is widely used in blotting methods (Southern and Northern), in situ hybridization, and various hybridization-based assays, where the DIG signal can be amplified or multiplexed with different antibody conjugates.

Safety and handling considerations follow standard laboratory practices for immunoassay reagents and cardiac glycoside derivatives. Digoxigenin itself is used solely as a molecular biology reagent and does not have established pharmacological activity in this context.