title: Mitochondrial single nucleotide polymorphism genotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using cleavable biotinylated dideoxynucleotides.
abstract: Characterization of mitochondrial DNA (mtDNA) single nucleotide polymorphisms (SNPs) and mutations is crucial for disease diagnosis, which requires accurate and sensitive detection methods and quantification due to mitochondrial heteroplasmy. We report here the characterization of mutations for myoclonic epilepsy with ragged red fibers syndrome using chemically cleavable biotinylated dideoxynucleotides and a mass spectrometry (MS)-based solid phase capture (SPC) single base extension (SBE) assay. The method effectively eliminates unextended primers and primer dimers, and the presence of cleavable linkers between the base and biotin allows efficient desalting and release of the DNA products from solid phase for MS analysis. This approach is capable of high multiplexing, and the use of different length linkers for each of the purines and each of the pyrimidines permits better discrimination of the four bases by MS. Both homoplasmic and heteroplasmic genotypes were accurately determined on different mtDNA samples. The specificity of the method for mtDNA detection was validated by using mitochondrial DNA-negative cells. The sensitivity of the approach permitted detection of less than 5% mtDNA heteroplasmy levels. This indicates that the SPC-SBE approach based on chemically cleavable biotinylated dideoxynucleotides and MS enables rapid, accurate, and sensitive genotyping of mtDNA and has broad applications for genetic analysis.
authors.affiliation: Columbia Genome Center, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Qiu
authors.forename: Shiv
authors.initials: S
authors.lastname: Kumar
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.forename: Jiesheng
authors.initials: J
authors.lastname: Lu
authors.forename: Shundi
authors.initials: S
authors.lastname: Shi
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Kalachikov
authors.forename: James J
authors.initials: JJ
authors.lastname: Russo
authors.forename: Ali B
authors.initials: AB
authors.lastname: Naini
authors.forename: Eric A
authors.initials: EA
authors.lastname: Schon
authors.forename: Jingyue
authors.initials: J
authors.lastname: Ju
mesh_terms: D001483:Base Sequence; D001710:Biotin / Q000737:chemistry; D019921:Biotinylation; D002460:Cell Line; D016172:DNA Fingerprinting / Q000379:methods*; D004272:DNA, Mitochondrial / Q000032:analysis*; D054306:Dideoxynucleotides / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D017243:MERRF Syndrome / Q000175:diagnosis / Q000235:genetics*; D008928:Mitochondria / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011687:Purines / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D019809:Streptavidin / Q000737:chemistry
chemical_list: D004272:DNA, Mitochondrial; D054306:Dideoxynucleotides; D011687:Purines; D011743:Pyrimidines; D001710:Biotin; D019809:Streptavidin