Mass-spectrometric analysis of known gene mutations

摘要

A method for mass-spectrometric analysis of known genetic mutations, using modified nucleoside triposhosphates to improve the performance, is new. The method comprises: (1) amplifying a DNA sequence by polymerase chain reaction (PCR) using primers selected to amplify a sequence containing the mutation; (2) adding a particular set of modified nucleoside triphosphates (NTPs) to effect limited extension of already present or newly added primers, where: (a) the extension reaction stops at the next occurrence of a particular base in the DNA strand being copied; (b) the extension reaction proceeds up to or past the mutation site, so that wild-type amplification products will have a different molecular weight from mutant amplification products; and (c) the modification of the NTPs results in stabilization of the DNA chains during ionization, a reduction in ion adduct formation, an increase in ionization yields and/or a change in the mass of the DNA chains; (3) performing the limited primer extension using an enzyme that generates the complement of the DNA strand being copied; (4) performing at least partial primer degradation and optionally further modification of the amplification products; and (5) determining the mass of the modified amplification products by mass spectrometry and assigning the masses to wild type or mutant. An Independent claim is also included for a kit which can be used to carry out the novel method.