Amplification and loss of dihydrofolate reductase genes in a Chinese hamster ovary cell line.
AUTOR(ES)
Kaufman, R J
RESUMO
During stepwise increases in the methotrexate concentration in culture medium, we selected Chinese hamster ovary cells that contained elevated dihydrofolate reductase levels which were proportional to the number of dihydrofolate reductase gene copies (i.e., gene amplification). We studied the dihydrofolate reductase levels in individual cells that underwent the initial steps of methotrexate resistance by using the fluorescence-activated cell sorter technique. Such cells constituted a heterogeneous population with differing dihydrofolate reductase levels, and they characteristically lost the elevated enzyme levels when they were grown in the absence of methotrexate. The progeny of individual cells with high enzyme levels behaved differently and could lose all or variable numbers of the amplified genes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=369733Documentos Relacionados
- Amplification of a cloned Chinese hamster dihydrofolate reductase gene after transfer into a dihydrofolate reductase-deficient cell line.
- Overexpression and amplification of five genes in a multidrug-resistant Chinese hamster ovary cell line.
- Organization and genesis of dihydrofolate reductase amplicons in the genome of a methotrexate-resistant Chinese hamster ovary cell line.
- Amplified dihydrofolate reductase genes are localized to a homogeneously staining region of a single chromosome in a methotrexate-resistant Chinese hamster ovary cell line.
- Overproduction of dihydrofolate reductase and gene amplification in methotrexate-resistant Chinese hamster ovary cells.