ELECTROPHORE MASS TAG DIDEOXY DNA-SEQUENCING

Toward a goal of dideoxy sequencing DNA utilizing electrophore labels, we prepared four electrophore-labeled DNA oligonucleotide primers. Ea ch primer has a different electrophore and DNA sequence but a common g lycol keto (alpha,beta-dihydroxyketo) release group, Cleavage of this latter group by either periodate oxidation or a thermal retroaldol rea ction releases the electrophores for detection by mass spectrometry. S uccessful sequencing data with these primers was obtained by capillary electrophoresis on an ABI Model 310 after fluorescence dideoxy termin ator cycle sequencing reactions were conducted. In a separate experime nt, it was demonstrated that a cocktail of the four electrophore DNA p rimers could be detected as a dried sample spot by CO2 laser desorptio n/capillary collection/gas chromatography electron capture mass spectr ometry. These results establish some feasibility for our long-term goa l of high-speed multiplex electrophore mass tag dideoxy DNA sequencing , Ultimately we plan to use a higher number of electrophore mass tags and to rely on direct detection of the desorbed electrophores by elect ron capture time-of-flight mass spectrometry.