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Updated: Aug 24, 2026

Proofreading and DNA Repair Assay Using Single Nucleotide Extension and MALDI-TOF Mass Spectrometry Analysis
Published on: June 19, 2018
SNP discrimination through proofreading and OFF-switch of exo+ polymerase
Jia Zhang1, Kai Li, Jose R Pardinas
1Genomapping Inc., Tianjin, China.
Abstract:
Single nucleotide polymorphisms (SNPs) are useful physical markers for genetic studies as well as the cause of some genetic diseases. To develop more reliable SNP assays, we examined the underlying molecular mechanisms by which deoxyribonucleic acid (DNA) polymerases with 3' exonuclease activity maintain the high fidelity of DNA replication. In addition to mismatch removal by proofreading, we have discovered a premature termination of polymerization mediated by a novel OFF-switch mechanism. Two SNP assays were developed, one based on proofreading using 3' end-labeled primer extension and the other based on the newly identified OFF-switch, respectively. These two new assays are well suited for conventional techniques, such as electrophoresis and microplates detection systems as well as the sophisticated microchips. Application of these reliable SNP assays will greatly facilitate genetic and biomedical studies in the postgenome era.
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