@article{Abdi01072002,
author = {Abdi, Fadi A. and Mundt, Mark and Doggett, Norman and Bradbury, E. Morton and Chen, Xian}, 
title = {Validation of DNA Sequences Using Mass Spectrometry Coupled with Nucleoside Mass Tagging},
volume = {12}, 
number = {7}, 
pages = {1135-1141}, 
year = {2002}, 
doi = {10.1101/gr.221402}, 
abstract ={We present a mass spectrometry (MS)-based nucleoside-specific mass-tagging method to validate genomic DNA sequences containing ambiguities not resolved by gel electrophoresis. Selected types of13C/15N-labeled dNTPs are used in PCR amplification of target regions followed by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)-MS analysis. From the mass difference between the PCR products generated with unlabeled nucleosides and products containing 13C/15N-labeled nucleosides, we determined the base composition of the genomic regions of interest. Two approaches were used to verify the target regions: The first approach used nucleosides partially enriched with stable isotopes to identify a single uncalled base in a gel electrophoresis-sequenced region. The second approach used mass tags with 100% heavy nucleosides to examine a GC-rich region of a polycytidine string with an unknown number of cytidines. By use of selected13C/15N-labeled dNTPs (dCTPs) in PCR amplification of the target region in tandem with MALDI-TOF-MS, we determined precisely that this string contains 11 cytidines. Both approaches show the ability of our MS-based mass-tagging strategy to solve critical questions of sequence identities that might be essential in determining the proper reading frames of the targeted regions.}, 
URL = {http://genome.cshlp.org/content/12/7/1135.abstract}, 
eprint = {http://genome.cshlp.org/content/12/7/1135.full.pdf+html}, 
journal = {Genome Research} 
}