Telomere G-overhang length measurement method 1: the DSN method

Methods Mol Biol. 2011;735:47-54. doi: 10.1007/978-1-61779-092-8_5.


Telomeres terminate in 3' single-stranded G-overhangs that function in telomere end protection and telomerase action. An accurate measurement of overhang length is challenging due to the presence of many kilobases of double-stranded telomere DNA. Here, a simple method is described that utilizes duplex-specific nuclease (DSN) to digest all genomic DNA including telomeres, leaving the single-stranded overhangs intact. The telomere single-strand G-rich overhang length can then be determined by Southern blot-based assays.

MeSH terms

  • Base Sequence
  • DNA, Single-Stranded / genetics
  • DNA, Single-Stranded / metabolism
  • Deoxyribonucleases / metabolism*
  • Guanine / analysis*
  • Guanine / metabolism
  • Humans
  • Repetitive Sequences, Nucleic Acid / genetics
  • Telomere / chemistry*
  • Telomere / genetics
  • Telomere / metabolism*


  • DNA, Single-Stranded
  • Guanine
  • Deoxyribonucleases