title: Pyrophosphorolysis-activated polymerization (PAP): application to allele-specific amplification.
abstract: To measure mutation load or to detect minimal residual disease, a robust method for identifying one mutant allele in the range of 10(6)-10(9) wild-type alleles would be advantageous. Herein, we present evidence that pyrophosphorolysis-activated polymerization (PAP) has the potential to provide a highly specific and robust method of allele-specific amplification if DNA polymerases with higher pyrophosphorolysis activity can be found or engineered. In PAP, pyrophosphorolysis and polymerization by DNA polymerase are coupled serially by utilizing a pyrophosphorolysis-activatable oligonucleotide (P*). P*, which is an allele-specific oligonucleotide with a dideoxynucleotide at the 3' terminus, can be activated by pyrophosphorolysis to remove the 3' terminal dideoxynucleotide in the presence of pyrophosphate (PPi) and the complementary strand of the allelic template; then the activated P* can be extended by DNA polymerization. Specificity results from both pyrophosphorolysis and polymerization because significant nonspecific amplification requires the combination of mismatch pyrophosphorolysis and misincorporation by the DNA polymerase, which is an extremely rare event. Proof of principle has been achieved with a polymorphic site within the human D1 dopamine receptor gene. The effects of the dideoxyoligonucleotide sequences, DNA polymerases, PPi concentrations, allele-specific templates, pH and dNTP concentrations were examined.
authors.affiliation: City of Hope National Medical Center, Duarte, CA, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Liu
authors.forename: S S
authors.initials: SS
authors.lastname: Sommer
mesh_terms: D000483:Alleles; D001483:Base Sequence; D004252:DNA Mutational Analysis / Q000379:methods*; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009154:Mutation / Q000235:genetics; D018365:Neoplasm, Residual / Q000175:diagnosis / Q000235:genetics; D009838:Oligodeoxyribonucleotides / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods*; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D017447:Receptors, Dopamine D1 / Q000235:genetics*; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D013698:Templates, Genetic
chemical_list: D009838:Oligodeoxyribonucleotides; D017447:Receptors, Dopamine D1; D004259:DNA-Directed DNA Polymerase; D004262:DNA Restriction Enzymes