scholarly journals Biochemical evidence for multiple independent emetine resistance genes in Chinese hamster cells.

1983 ◽  
Vol 3 (2) ◽  
pp. 198-202 ◽  
Author(s):  
K Nielsen-Smith ◽  
S McGill ◽  
M Frahm ◽  
D J Roufa
Keyword(s):  
Molecular Basis ◽  
Ribosomal Proteins ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Ovary Cell ◽  
Chinese Hamster Cells ◽  
Molecular Product ◽  
Translation Apparatus ◽  
Hybrid Clones

Hybridization-complementation studies indicated that mutations in multiple genes can render Chinese hamster cells resistant to the alkaloid translation inhibitor emetine. Two of the genes, emtA and emtB, recognized in Chinese hamster lung and ovary cell lines, respectively, are known to affect the ribosomes of the cells directly. Although mutations in a third gene, emtC, affect the translation apparatus of Chinese hamster peritoneal cells in vitro (Wasmuth et al., Mol. Cell. Biol. 1:58-65, 1981), the molecular product of the emtC locus remains to be determined. To study the molecular basis for genetic complementation among emetine-resistant Chinese hamster cell mutants, we analyzed ribosomal proteins elaborated by complementing, emetine-sensitive hybrid clones (EmtB X EmtA and EmtB X EmtC) and by emetine-resistant clones that segregated from the hybrids. The electrophoretic forms of ribosomal protein S14 (the emtB gene product) elaborated by these clones indicated that the EmtA and EmtC phenotypes are independent of the emtB locus and that the emtA and emtC loci are not chromosomally linked to emtB.

Biochemical evidence for multiple independent emetine resistance genes in Chinese hamster cells

1983 ◽  
Vol 3 (2) ◽  
pp. 198-202
Author(s):  
K Nielsen-Smith ◽  
S McGill ◽  
M Frahm ◽  
D J Roufa
Keyword(s):  
Molecular Basis ◽  
Ribosomal Proteins ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Ovary Cell ◽  
Chinese Hamster Cells ◽  
Molecular Product ◽  
Translation Apparatus ◽  
Hybrid Clones

Hybridization-complementation studies indicated that mutations in multiple genes can render Chinese hamster cells resistant to the alkaloid translation inhibitor emetine. Two of the genes, emtA and emtB, recognized in Chinese hamster lung and ovary cell lines, respectively, are known to affect the ribosomes of the cells directly. Although mutations in a third gene, emtC, affect the translation apparatus of Chinese hamster peritoneal cells in vitro (Wasmuth et al., Mol. Cell. Biol. 1:58-65, 1981), the molecular product of the emtC locus remains to be determined. To study the molecular basis for genetic complementation among emetine-resistant Chinese hamster cell mutants, we analyzed ribosomal proteins elaborated by complementing, emetine-sensitive hybrid clones (EmtB X EmtA and EmtB X EmtC) and by emetine-resistant clones that segregated from the hybrids. The electrophoretic forms of ribosomal protein S14 (the emtB gene product) elaborated by these clones indicated that the EmtA and EmtC phenotypes are independent of the emtB locus and that the emtA and emtC loci are not chromosomally linked to emtB.

CHINESE HAMSTER CELL LINES RESISTANT TO THE CYTOTOXIC ACTION OF FLUORIDE

1978 ◽  
Vol 20 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Ralph Mankovitz ◽  
R. Kisilevsky ◽  
Marie Florian
Keyword(s):  
Molecular Basis ◽  
Culture Medium ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Ovary Cell ◽  
Cytotoxic Action ◽  
Wild Type ◽  
Resistant Lines ◽  
Ovary Cell Line ◽  
Resistant Cells

The proliferation and efficiency of colony formation of a Chinese hamster ovary cell line, CHO, was found to be inhibited by concentrations of fluoride ≥ 10−3 M. From mutagenized populations of CHO cells, clones were isolated that were from 1.6 to 13 times more resistant than the wild-type to the cytotoxic action of fluoride. The resistant clones were found to be stable in the absence of selection. The fluoride sensitivity of wild-type and fluoride resistant clones was not altered by changes in the pyruvate concentration in the culture medium, indicating that the cytotoxic effect of fluoride is not due to the action of fluoride on the glycolytic pathway. On the other hand, both the incorporation of 3H-leucine into acid precipitable material and the distribution of polyribosomes were sensitive only to fluoride concentrations that were cytotoxic, suggesting that the molecular basis of fluoride induced cytotoxicity in both wild-type and fluoride resistant cells is the sensitivity of protein synthesis to fluoride. At concentrations of fluoride at which the wild-type cells are inhibited but fluoride resistant cells are not, the intracellular concentration of fluoride in the fluoride resistant cells was found to be 1/5 to 1/10 that of the wild-type, suggesting that fluoride exclusion is the basis for resistance in the resistant lines.

Killing of Chinese hamster cells in vitro by heating under hypoxic or aerobic conditions

1974 ◽  
Vol 10 (10) ◽  
pp. 691-693 ◽  
Author(s):  
Leo E. Gerweck ◽  
Edward L. Gillette ◽  
William C. Dewey
Keyword(s):  
Chinese Hamster ◽  
Aerobic Conditions ◽  
Chinese Hamster Cells

Similar 150-kilobase DNA sequences are amplified in independently derived methotrexate-resistant Chinese hamster cells

1985 ◽  
Vol 5 (4) ◽  
pp. 619-627
Author(s):  
M Montoya-Zavala ◽  
J L Hamlin
Keyword(s):  
Dna Sequence ◽  
Cell Lines ◽  
Dihydrofolate Reductase ◽  
Dna Sequences ◽  
Consensus Sequence ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Chinese Hamster Cells ◽  
Reductase Gene ◽  
Reductase Domain

We have isolated overlapping recombinant cosmids that represent 150 kilobases of contiguous DNA sequence from the amplified dihydrofolate reductase domain of a methotrexate-resistant Chinese hamster ovary cell line (CHOC 400). This sequence includes the 25-kilobase dihydrofolate reductase gene and an origin of DNA synthesis. Eight cosmids that span this domain have been utilized as radioactive hybridization probes to analyze the similarities among the dihydrofolate reductase amplicons in four independently derived methotrexate-resistant Chinese hamster cell lines. We have observed no significant differences among the four cell lines within the 150-kilobase DNA sequence that we have examined, except for polymorphisms that result from the amplification of one or the other of two possible alleles of the dihydrofolate reductase domain. We also show that the restriction patterns of the amplicons in these four resistant cell lines are virtually identical to that of the corresponding, unamplified sequence in drug-susceptible parental cells. Furthermore, measurements of the relative copy numbers of fragments from widely separated regions of the amplicon suggest that all fragments in this 150-kilobase region may be amplified in unison. Our data show that in methotrexate-resistant Chinese hamster cells, the amplified unit is large relative to the dihydrofolate reductase gene itself. Furthermore, within the 150-kilobase amplified consensus sequence that we have examined, significant rearrangements do not seem to occur during the amplification process.

THE ESTABLISHMENT AND CHROMOSOME ANALYSIS OF A NEW CELL LINE OF CHINESE HAMSTER FROM SPONTANEOUS TRANSFORMATION IN VITRO

1971 ◽  
Vol 13 (1) ◽  
pp. 9-13 ◽  
Author(s):  
C. C. Lin ◽  
T. D. Chang ◽  
Virginia Niewczas-Late
Keyword(s):  
Cell Line ◽  
Chinese Hamster ◽  
Chromosome Analysis ◽  
Cell Types ◽  
Selective Advantage ◽  
Chinese Hamster Cell ◽  
Major Type ◽  
Spontaneous Transformation ◽  
Chinese Hamster Cell Line

A male Chinese hamster cell line has been established through spontaneous transformation in a skin culture. Chromosome studies at passage 13 revealed one major and one minor type of pseudodiploid cells (77.3 and 20%). At passage 42, only the major subline persisted (78%). The two sublines, especially the major one, had selective advantage over other cell types in this cell line probably because they were more nearly genetically balanced. Autoradiographic studies indicated no overall increase in late replicating chromosomal elements in the two sublines. Both cell types lacked the X chromosome and chromosome 6, but they were largely compensated for by the presence of new marker chromosomes. However, more chromosomal material was missing in the minor type than in the major type, and this may account for the lower adaptability of the former.

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