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Chinese hamster ovary cell mutants specifically affected in the phosphorylation of C-purine nucleosides

K D Mehta, R S Gupta

    Canadian Journal of Biochemistry and Cell Biology = Revue Canadienne De Biochimie Et Biologie Cellulaire
    |September 1, 1985
    PubMed

    Insights

    Two mutant types resistant to nucleoside analogs were found in Chinese hamster ovary cells. FomR mutants resist C-nucleosides by altering adenosine kinase, impacting C-purine nucleoside phosphorylation.

    Area of Science:

    • Cell Biology
    • Biochemistry
    • Genetics

    Background:

    • Purine nucleoside analogs are used in research and therapy.
    • Understanding resistance mechanisms is crucial for drug development.
    • Chinese hamster ovary (CHO) cells are a common model for genetic studies.

    Purpose of the Study:

    • To isolate and characterize mutants resistant to purine nucleoside analogs.
    • To investigate the specific mechanisms of resistance in different mutant types.
    • To elucidate the role of adenosine kinase in nucleoside analog metabolism.

    Main Methods:

    • Isolation of resistant mutants (FomR and Toyr) in CHO cells.
    • Assessing cross-resistance patterns to various nucleoside analogs.
    • Measuring cellular uptake and phosphorylation of radiolabeled nucleosides ([3H]adenosine, [3H]tubercidin, [3H]formycin A).

    Main Results:

    • FomR mutants showed cross-resistance to C-nucleosides but not N-nucleosides.
    • Toyr mutants exhibited broad cross-resistance to both C- and N-adenosine analogs.
    • FomR mutants displayed reduced phosphorylation of [3H]formycin A only, while Toyr mutants showed reduced phosphorylation of all tested compounds.
    • Genetic lesions in FomR mutants specifically affect C-purine nucleoside phosphorylation.

    Conclusions:

    • Two distinct resistance mechanisms to purine nucleoside analogs exist in CHO cells.
    • FomR mutants possess a novel defect in adenosine kinase affecting C-purine nucleoside phosphorylation.
    • These findings provide insights into nucleoside analog metabolism and resistance pathways.

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