UNIT 8.4 Labeling DNA and Preparing Probes

  1. Karl A. Haushalter

Published Online: 1 OCT 2008

DOI: 10.1002/9780470089941.et0804s00

Current Protocols Essential Laboratory Techniques

Current Protocols Essential Laboratory Techniques

How to Cite

Haushalter, K. A. 2008. Labeling DNA and Preparing Probes. Current Protocols Essential Laboratory Techniques. 00:8.4:8.4.1–8.4.22.

Author Information

  1. Harvey Mudd College, Claremont, California

Publication History

  1. Published Online: 1 OCT 2008
  2. Published Print: JAN 2008


Labeling nucleic acids with radioisotopes, fluorophores, biotin, or digoxigenin enables their detection and analysis. When designing a labeling strategy, consider the intended application, the source of nucleic acid, and the type of label to incorporate. DNA oligonucleotides can be 5′ end-labeled with radioisotopes in a reaction catalyzed by T4 polynucleotide kinase, or nonisotopic labels can be incorporated into oligonucleotides during DNA synthesis. Larger DNA substrates can be labeled by 5′ end labeling (radioisotopes) or labeled uniformly along the length of the DNA by nick translation or random primed synthesis (using radioisotope or nonisotopic labels). The labeled DNA can be used for a variety of applications, including probing Southern blots, probing northern blots, in situ hybridization, quantifying real-time PCR results, and gel shift assays.


  • nucleic acid probe;
  • end-labeling;
  • random primed synthesis;
  • nick translation;
  • radioisotope;
  • fluorophore;
  • biotin;
  • digoxigenin;
  • polynucleotide kinase;
  • terminal transferase