AI Article Synopsis
- Chinese hamster ovary cells were selected for high resistance to methotrexate through a detailed multistep process.
- These resistant cells show increased production of dihydrofolate reductase, a key enzyme, compared to sensitive cells, which is linked to gene amplification.
- Analysis reveals variations in enzyme structure and chromosomal differences among the resistant isolates, indicating genetic diversity in their resistance mechanisms.
Article Abstract
Stable isolates of Chinese hamster ovary cells that are highly resistant to methotrexate have been selected in a multistep selection process. Quantitative immunoprecipitations have indicated that these isolates synthesize dihydrofolate reductase at an elevated rate over its synthesis in sensitive cells. Restriction enzyme and Southern blot analyses with a murine reductase cDNA probe indicate that the highly resistant isolates contain amplifications of the dihydrofolate reductase gene number. Depending upon the parenteral line used to select these resistant cells, they overproduce either a wild-type enzyme or a structurally altered enzyme. Karyotype analysis shows that some of these isolates contain chromosomes with homogeneously staining regions whereas others do not contain such chromosomes.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC369786 | PMC |
| http://dx.doi.org/10.1128/mcb.2.3.275-285.1982 | DOI Listing |
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