SELECTIVE CAPTURE OF ACENTRIC FRAGMENTS BY MICRONUCLEI PROVIDES A RAPID METHOD FOR PURIFYING EXTRACHROMOSOMALLY AMPLIFIED DNA

The amplification and overexpression of a number of oncogenes is stron gly associated with the progression of a variety of different cancers. We now present a strategy to purify amplified DNA on double minute ch romosomes (DMs) to enable analysis of their prevalence and contributio n to tumourigenesis, Using cell lines derived from four different tumo ur types, we have developed a general and rapid method to purify micro nuclei that are known to entrap extrachromosomal elements. The isolate d DNA is highly enriched in DM sequences and can be used to prepare pr obes to localize the progenitor single copy chromosomal regions. The c apture of DMs by micronuclei appears to be dependent on their lack of a centromere rather than their small size.