Specific terminal labeling of DNA molecules

Biotechniques. 2007 May;42(5):622-6. doi: 10.2144/000112418.


We report a simple method to directly label or modify a specific terminus of linear DNA molecules. The method is based upon our finding that a presumably triple-stranded structure by RecA-mediated formation at the terminus formed with deoxyoligonucleotides, whose sequence is complementary to the 5' terminus of one of the strands of a double-stranded DNA molecule, is quite stable and can serve as a template for DNA polymerase reaction, with the nucleotides being incorporated by an exchange reaction. This novel type of nucleotide incorporation has made it possible to label a specific terminus of target double-stranded DNA molecules by a direct means (without amplification) regardless of its molecular size, a procedure previously unavailable. As an application, we show that large DNA molecules can be fixed to a solid support in a specific orientation, thus being utilized for various analytical purposes of DNA molecules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA, Viral / analysis
  • DNA, Viral / chemistry*
  • DNA, Viral / metabolism*
  • Nucleotides / metabolism
  • Staining and Labeling / methods*
  • Templates, Genetic


  • DNA, Viral
  • Nucleotides