Unstable and stable CAD gene amplification: importance of flanking sequences and nuclear environment in gene amplification.

摘要: We analyzed the amplification of CAD gene in independently isolated N-(phosphonacetyl)-L-aspartate-resistant clones derived from single parental two mouse cell lines. report for first time that is amplified unstably cells, degree instability varies greatly between clones, and minute chromosomes highly unstable chromosomelike structures contain sequences. These data are most consistent with idea unit each clone consists different flanking DNA such differences engender sequences unequal stability. also introduced chromosome containing into hamster cells by microcell-mediated transfer to determine whether propensity extrachromosomal would prevail nuclear environment. was stably expanded chromosomal regions seven hybrids were analyzed. This observation environment influences mutants intra- or extrachromosomally will be isolated.