Amplification of Several Different Genes in Multidrug-Resistant Chinese Hamster Cell Lines

摘要: In 1984, when we started our experiments on genes involved in multidrug resistance (MDR), were struck by the genetic instability and phenotypic diversity of MDR. Several MDR cell lines had been shown to rapidly revert normal grown under nonselective conditions, a property associated with unstable forms gene amplification, i.e., double-minute (DM) chromosomes. Indeed, DM chromosomes homogeneously staining regions (HSRs), cytogenetic representations observed cells (see Chapters 6–8). It seemed likely, therefore, that would be increased expression one or more genes. Phenotypic appeared not due interaction single diverse backgrounds, because parental line could give rise several daughter differed detailed spectrum cross-resistance 1 2). This strongly indicated than contribute We have tried make an inventory these hamster collecting overexpressed resistant relative sensitive line. Whereas Roninson co-workers developed DNA-DNA renaturation approach directly isolate amplified Chapter 3), made clone banks DNA complementary mRNAs selected cDNAs corresponding present at levels