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Updated: Aug 26, 2026

Proofreading and DNA Repair Assay Using Single Nucleotide Extension and MALDI-TOF Mass Spectrometry Analysis
Published on: June 19, 2018
Straightforward detection of SNPs in double-stranded DNA by using exonuclease III/nuclease S1/PNA system
Binzhi Ren1, Jing-Min Zhou, Makoto Komiyama
1Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.
Abstract:
Single-nucleotide polymorphisms (SNPs) in double-stranded DNA (dsDNA) have been straightforwardly genotyped by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS). Peptide nucleic acid (PNA), a DNA analog, was used as a probe molecule. In its presence, genomic dsDNA was first treated with exonuclease III and then with nuclease S1. By these one-pot reactions, single-stranded DNA fragments including the SNP sites were formed in situ. These fragments were directly analyzed by MALDI-TOF MS, and the identity of the DNA base at the SNP site was determined in terms of mass number. By using two or more PNA probes simultaneously, multiplex analysis was also successful. Various genotypes of apolipoprotein E gene (epsilon2/epsilon2, epsilon3/epsilon3, epsilon4/epsilon4, epsilon2/epsilon3 and epsilon3/epsilon4) were identified from dsDNA obtained by PCR from corresponding patients.
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