Assignment of the gene governing cellular ouabain resistance to Mus musculus chromosome 3 using human/mouse microcell hybrids

Human/mouse microcell hybrids were used to establish the assignment of the gene governing resistance to the cardiac glycoside ouabain (Oua-1) to Mus musculus chromosome 3. Microcells were prepared from primary mouse embryo fibroblasts and fused with HeLa S3 cells, and microcell hybrids were isolated and maintained in medium containing 10^–6m ouabain. Resistance to ouabain was not expressed concordantly with any of 26 murine isozyme markers. Karyotypic analysis of five primary clones showed that one to five murine chromosomes had been transferred from donor to recipient in these experiments. Only mouse chromosome 3 was common to all ouabain-resistant primary clones. Both ouabain-resistant and -sensitive subclones were isolated from hybrids grown in the absence of selective pressure, and karyotyping showed that loss of resistance to ouabain was concordant with the loss of murine chromosome 3.These studies were supported by Grant GM9966 from the National Institutes of Health.