Gene amplification accompanies low level increases in the activity of dihydrofolate reductase in antifolate-resistant chinese hamster lung cells containing abnormally banding chromosomes

TY - JOUR

T1 - Gene amplification accompanies low level increases in the activity of dihydrofolate reductase in antifolate-resistant chinese hamster lung cells containing abnormally banding chromosomes

AU - Lewis, J. A.

AU - Biedler, J. L.

AU - Melera, P. W.

PY - 1982/8/1

Y1 - 1982/8/1

N2 - Three independently-derived, antifolate-resistant Chinese hamster lung cell lines that exhibit low level increases in dihydrofolate reductase (DHFR) activity, i.e., three-to fivefotd vs. controls, have been compared with drug-sensitive cells to determine relative DHFR gene content. With a solution hybridization technique that makes use of genomic DNA and a cloned double-stranded Chinese hamster DHFR cDNA probe, it has been found that the enzyme activity increases are associated with an approximately proportionate amplification of DHFR genes. Trypsin-Giemsa staining techniques and hybridizations in situ further show that the amplified DHFR genes are located within abnormally banding regions along chromosome 2q and also suggest that, in each subline, only one chromosome 2 homolog is initially involved in the amplification process.

AB - Three independently-derived, antifolate-resistant Chinese hamster lung cell lines that exhibit low level increases in dihydrofolate reductase (DHFR) activity, i.e., three-to fivefotd vs. controls, have been compared with drug-sensitive cells to determine relative DHFR gene content. With a solution hybridization technique that makes use of genomic DNA and a cloned double-stranded Chinese hamster DHFR cDNA probe, it has been found that the enzyme activity increases are associated with an approximately proportionate amplification of DHFR genes. Trypsin-Giemsa staining techniques and hybridizations in situ further show that the amplified DHFR genes are located within abnormally banding regions along chromosome 2q and also suggest that, in each subline, only one chromosome 2 homolog is initially involved in the amplification process.

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U2 - https://doi.org/10.1083/jcb.94.2.418

DO - https://doi.org/10.1083/jcb.94.2.418

M3 - Article

C2 - 7107708

VL - 94

SP - 418

EP - 424

JO - The Journal of cell biology

JF - The Journal of cell biology

SN - 0021-9525

IS - 2

ER -