Complementation of DNA-repair deficiencies in Chinese hamster ovary cells

1987 ◽  
Vol 65 (9) ◽  
pp. 803-810 ◽  
Author(s):  
Jaime S. Rubin ◽  
Gordon F. Whitmore
Keyword(s):  
Dna Repair ◽  
Chinese Hamster Ovary ◽  
Excision Repair ◽  
Chinese Hamster Ovary Cells ◽  
Genetic Locus ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Wild Type ◽  
Repair Defect ◽  
Mutant Lines

Genetic mapping studies in bacterial, lower eukaryotic, and mammalian systems have demonstrated that the enzyme or enzyme complex involved in the initial incision step of the DNA excision repair pathway is coded for by more than one genetic locus. This paper reports the results of complementation studies that were performed with a number of DNA repair deficient Chinese hamster ovary cell lines. Complementation abilities were measured by comparing the survival of selected mutant × mutant hybrids with that of the tetrapoloid wild type after exposure to a number of physical and chemical agents. In all cases studied, hybrids formed from two different mutant lines showed resistance similar to that of the wild-type line. These results not only demonstrate that the mutant lines were in different complementation groups, but that complementation of a DNA-repair defect associated with one particular agent can complement the defect for another DNA-damaging agent.

scholarly journals Sensitivity of a mutator gene in Chinese hamster ovary cell to deoxynucleoside triphosphate pool alterations.

1981 ◽  
Vol 1 (7) ◽  
pp. 652-660 ◽  
Author(s):  
M Meuth
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Genetic Locus ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Single Mutation ◽  
Wild Type ◽  
Ovary Cells ◽  
Mutator Gene ◽  
Mutator Activity

The Thy- mutants of Chinese hamster ovary cells have a 5- to 10-fold elevated pool of deoxycytidine 5'-triphosphate (dCTP) and are auxotrophic for thymidine as an apparent consequence of a single mutation. thy is also a mutator gene, elevating the spontaneous rate of mutation 5- to 200-fold for at least two genetic markers. Previous experiments suggested that this mutator activity was caused by the elevated pool of dCTP in Thy- cells. To test this, the dCTP and deoxythymidine 5'-triphosphate (dTTP) pools were manipulated by altering the external concentration of thymidine in the growth medium. The rate of mutation at one genetic locus, ouabain resistance, was directly related to cellular dCTP content. At the highest level of dCTP the rate in one Thy- strain was approximately 200 times that of wild-type cells. However, the relationship between dCTP content and the rate of mutation at the ouabain locus was different for two mutator strains and wild-type cells. The rate of mutation at a second locus, thioguanine resistance, was increased approximately 10-fold over wild type regardless of the dCTP-dTTP pools. These experiments suggest that the mutator activity of thy is clearly related to dCTP content, but the dCTP level alone does not appear to be the cause of the mutator.

Sensitivity of a mutator gene in Chinese hamster ovary cell to deoxynucleoside triphosphate pool alterations

1981 ◽  
Vol 1 (7) ◽  
pp. 652-660
Author(s):  
M Meuth
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Genetic Locus ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Single Mutation ◽  
Wild Type ◽  
Ovary Cells ◽  
Mutator Gene ◽  
Mutator Activity

The Thy- mutants of Chinese hamster ovary cells have a 5- to 10-fold elevated pool of deoxycytidine 5'-triphosphate (dCTP) and are auxotrophic for thymidine as an apparent consequence of a single mutation. thy is also a mutator gene, elevating the spontaneous rate of mutation 5- to 200-fold for at least two genetic markers. Previous experiments suggested that this mutator activity was caused by the elevated pool of dCTP in Thy- cells. To test this, the dCTP and deoxythymidine 5'-triphosphate (dTTP) pools were manipulated by altering the external concentration of thymidine in the growth medium. The rate of mutation at one genetic locus, ouabain resistance, was directly related to cellular dCTP content. At the highest level of dCTP the rate in one Thy- strain was approximately 200 times that of wild-type cells. However, the relationship between dCTP content and the rate of mutation at the ouabain locus was different for two mutator strains and wild-type cells. The rate of mutation at a second locus, thioguanine resistance, was increased approximately 10-fold over wild type regardless of the dCTP-dTTP pools. These experiments suggest that the mutator activity of thy is clearly related to dCTP content, but the dCTP level alone does not appear to be the cause of the mutator.

Complementation of a methotrexate uptake defect in Chinese hamster ovary cells by DNA-mediated gene transfer

1989 ◽  
Vol 9 (4) ◽  
pp. 1754-1758
Author(s):  
T M Underhill ◽  
W F Flintoff
Keyword(s):  
Gene Transfer ◽  
Dna Sequences ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Wild Type ◽  
Ovary Cells ◽  
Ovary Cell Line ◽  
Human Specific

A methotrexate-resistant Chinese hamster ovary cell line deficient in methotrexate uptake has been complemented to methotrexate sensitivity by transfection with DNA isolated from either wild-type Chinese hamster ovary or human G2 cells. Primary and secondary transfectants regained the ability to take up methotrexate in a manner similar to that of wild-type cells, and in the case of those transfected with human DNA, to contain human-specific DNA sequences. The complementation by DNA-mediated gene transfer of this methotrexate-resistant phenotype provides a basis for the cloning of a gene involved in methotrexate uptake.

scholarly journals Taxol-dependent mutants of Chinese hamster ovary cells with alterations in alpha- and beta-tubulin.

1986 ◽  
Vol 102 (4) ◽  
pp. 1522-1531 ◽  
Author(s):  
M J Schibler ◽  
F Cabral
Keyword(s):  
Chinese Hamster Ovary ◽  
Mitotic Spindle ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Two Dimensional ◽  
Wild Type ◽  
Beta Tubulin ◽  
Alpha Tubulin ◽  
Absolute Dependence

Chinese hamster ovary cell mutants resistant to the microtubule stabilizing drug taxol were isolated in a single step. Of these 139 drug-resistant mutants, 59 exhibit an absolute requirement for taxol for normal growth and division, 13 have a partial requirement, and 69 grow normally without the drug. Two-dimensional gel analysis of whole cell proteins reveal "extra" spots representing altered tubulins in 13 of the mutants. Six of these have an altered alpha-tubulin and seven have an altered beta-tubulin. Cells with an absolute dependence on taxol become large and multinucleated when deprived of the drug. In contrast, partially dependent cells exhibit some multinucleation, but most cells appear normal. In one mutant that has an absolute dependence on taxol, the cells appear to die more quickly and their nuclei do not increase in size or number. As previously found for another taxol-dependent mutant (Cabral, F., 1983, J. Cell. Biol., 97:22-29), the taxol dependence of the mutants described in this paper behaves recessively in somatic cell hybrids, and the cells are more susceptible to being killed by colcemid than are the wild-type parental cells. When compared with wild-type cells, taxol-dependent mutants have normal arrays of cytoplasmic microtubules but form much smaller mitotic spindles in the presence of taxol. When deprived of the drug, however, these mutants cannot complete assembly of the mitotic spindle apparatus, as judged by tubulin immunofluorescence. Thus, the defects leading to taxol dependence in these mutants with defined alterations in alpha- and beta-tubulin appear to result from the cell's inability to form a functional mitotic spindle. Reversion analysis indicates that the properties of at least one alpha-tubulin mutant are conferred by the altered tubulin seen on two-dimensional gels.

scholarly journals Complementation of a methotrexate uptake defect in Chinese hamster ovary cells by DNA-mediated gene transfer.

1989 ◽  
Vol 9 (4) ◽  
pp. 1754-1758 ◽  
Author(s):  
T M Underhill ◽  
W F Flintoff
Keyword(s):  
Gene Transfer ◽  
Dna Sequences ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Wild Type ◽  
Ovary Cells ◽  
Ovary Cell Line ◽  
Human Specific

A methotrexate-resistant Chinese hamster ovary cell line deficient in methotrexate uptake has been complemented to methotrexate sensitivity by transfection with DNA isolated from either wild-type Chinese hamster ovary or human G2 cells. Primary and secondary transfectants regained the ability to take up methotrexate in a manner similar to that of wild-type cells, and in the case of those transfected with human DNA, to contain human-specific DNA sequences. The complementation by DNA-mediated gene transfer of this methotrexate-resistant phenotype provides a basis for the cloning of a gene involved in methotrexate uptake.

Malignancy-related characteristics of wild type and drug-resistant chinese hamster ovary cells

Pathology ◽  
1993 ◽  
Vol 25 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Wanda B. Mackinnon ◽  
Marlen Dyne ◽  
Rebecca Hancock ◽  
Carolyn E. Mountford ◽  
Adrienne J. Grant ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Drug Resistant ◽  
Wild Type ◽  
Ovary Cells

scholarly journals Export from Pericentriolar Endocytic Recycling Compartment to Cell Surface Depends on Stable, Detyrosinated (Glu) Microtubules and Kinesin

2002 ◽  
Vol 13 (1) ◽  
pp. 96-109 ◽  
Author(s):  
Sharron X. Lin ◽  
Gregg G. Gundersen ◽  
Frederick R. Maxfield
Keyword(s):  
Elevated Temperature ◽  
Cell Surface ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Temperature Sensitive ◽  
Microtubule Organizing Center ◽  
Endocytic Recycling ◽  
In Cells

A significant fraction of internalized transferrin (Tf) concentrates in the endocytic recycling compartment (ERC), which is near the microtubule-organizing center in many cell types. Tf then recycles back to the cell surface. The mechanisms controlling the localization, morphology, and function of the ERC are not fully understood. We examined the relationship of Tf trafficking with microtubules (MTs), specifically the subset of stable, detyrosinated Glu MTs. We found some correlation between the level of stable Glu MTs and the distribution of the ERC; in cells with low levels of Glu MTs concentrated near to the centriole, the ERC was often tightly clustered, whereas in cells with higher levels of Glu MTs throughout the cell, the ERC was more dispersed. The clustered ERC in Chinese hamster ovary cells became dispersed when the level of Glu MTs was increased with taxol treatment. Furthermore, in a temperature-sensitive Chinese hamster ovary cell line (B104-5), the cells had more Glu MTs when the ERC became dispersed at elevated temperature. Microinjecting purified anti-Glu tubulin antibody into B104-5 cells at elevated temperature induced the redistribution of the ERC to a tight cluster. Microinjection of anti-Glu tubulin antibody slowed recycling of Tf to the cell surface without affecting Tf internalization or delivery to the ERC. Similar inhibition of Tf recycling was caused by microinjecting anti-kinesin antibody. These results suggest that stable Glu MTs and kinesin play a role in the organization of the ERC and in facilitating movement of vesicles from the ERC to the cell surface.

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