+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Isolation and characterization of dexamethasone-resistant mutants from human lymphoid cell line CEM-C7

Molecular and Cellular Biology 1(6): 512-521
Isolation and characterization of dexamethasone-resistant mutants from human lymphoid cell line CEM-C7
Fifty-four independent dexamethasone-resistant clones were isolated from the clonal, glucocorticoid-sensitive human leukemic T-cell line CEM-C7. Resistance to 1 microM dexamethasone was acquired spontaneously at a rate of 2.6 X 10(-5) per cell per generation as determined by fluctuation analysis. After mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), the phenotypic expression time for dexamethasone resistance was determined to be 3 days. Spontaneous acquisition of resistance to 0.1 mM 6-thioguanine appeared to occur at a much slower rate, 1.6 X 10(-6) per cell per generation. However, the expression time after MNNG mutagenesis for this resistant phenotype was greater than 11 days, suggesting that the different rates of acquisition for the two phenotypes measured by fluctuation analysis were the results of the disparate expression times. The mutagens ICR 191 and MNNG were effective in increasing the dexamethasone-resistant fraction of cells in mutagenized cultures; ICR 191 produced a 35.6-fold increase, and MNNG produced an 8.5-fold increase. All the spontaneous dexamethasone-resistant clones contained glucocorticoid receptors, usually less than half of the amount found in the parental clone. They are therefore strikingly different from dexamethasone-resistant clones derived from the mouse cell lines S49 and W7. Dexamethasone-resistant clones isolated after mutagenesis of CEM-C7 contained, on the average, lower concentrations of receptor than did those isolated spontaneously, and one clone contained no detectable receptor. These results are consistent with a mutational origin for dexamethasone resistance in these human cells at a haploid or functionally hemizygous locus. They also suggest that this is a useful system for mutation assay.

Accession: 043478643

PMID: 6965106

DOI: 10.1128/mcb.1.6.512

Related references

Isolation and characterization of apoptosis-resistant mutants from a radiosensitive mouse lymphoma cell line. Radiation Research. 149(1): 41-51,., 1998

ACNU-resistant mutants of 9L rat glioma cell line. Isolation and preliminary characterization of these subclones. Journal of Neurosurgery 63(4): 583-588, 1985

Isolation and characterization of 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole-resistant mutants of the Chinese hamster ovary cell line. Molecular and Cellular Biology 2(4): 467-477, 1982

Studies on the isolation and properties of drug resistant mutants from a human malignant cell line. Indian Journal of Cancer 5(3): 282-286, 1968

Isolation and preliminary characterization of u.v.-sensitive mutants from the human cell line EUE. Carcinogenesis 4(1): 39-44, 1983

Molybdate-sensitive and molybdate-resistant activation-labile glucocorticoid-receptor mutants of the human lymphoid cell line CEM-C7. Journal of Steroid Biochemistry 21(3): 227-236, 1984

Large scale production and characterization of dihydrofolate reductase from a methotrexate resistant human lymphoid cell line. Journal of Biosciences (Bangalore) 10(1): 37-48, 1986

Isolation of rifampin-resistant mutants of Listeria monocytogenes and their characterization by rpoB gene sequencing, temperature sensitivity for growth, and interaction with an epithelial cell line. Journal of Clinical Microbiology 37(9): 2913-2919, 1999

Isolation and characterization of VP-16 resistant human leukemia cell line. Biomedicine & PharmacoTherapy 44(1): 35-40, 1990

Isolation and characterization of an anthracycline-resistant human leukemic cell line. Cancer Research 45(8): 3657-3662, 1985