TY - JOUR
T1 - Abnormal regulation of de novo purine synthesis and purine salvage in a cultured mouse T‐cell lymphoma mutant partially deficient in adenylosuccinate synthetase
AU - Ullman, B.
AU - Clift, S. M.
AU - Cohen, A.
AU - Gudas, L. J.
AU - Levinson, B. B.
AU - Wormsted, M. A.
AU - Martin, D. W.
PY - 1979/4
Y1 - 1979/4
N2 - The isolation and characterization of a mutant murine T‐cell lymphoma (S49) with altered purine metabolism is described. This mutant, AU‐100, was isolated from a mutagenized populatio of S49 cells by virtue of its resistance to 0.1 mM 6‐azauridine in semisolid agarose. The AU‐100 cells are resistant to adenosine mediated cytotoxicity but are extraordinarily sensitive to killing by guanosine. High performance liquid chromatography of AU‐100 cells extracts has demonstrated that intracellular levels of GTP, IMP, and GMP are all elevated about 3‐fold over those levels found in wild type cells. The AU‐100 cells also contain an elevated intracellular level of pyrophosphoribosylphosphate (PPriboseP), which as in wild type cells is diminished by incubation of AU‐100 cells with adenosine. However AU‐100 cells synthesize purines de novo at a rate less than 35% of that found in wild type cells. In other growth rate experiments, the AU‐100 cell line was shown to be resistant to 6‐thioguanine and 6‐mercaptopurine. Levels of hypoxanthine‐guanine phosphoribosyltransferase (HGPRTase) measured in AU‐100 cell extracts, however, are 50‐66% greater than those levels of HGPRTase found in wild type cell extracts. Nevertheless this mutant S49 cell line cannot efficiently incorporate labeled hypoxanthine into nucleotides since the salvage enzyme HGPRTase is inhibited in vivo. The AU‐100 cell line was found to be 80% deficient in adenylosuccinate synthetase, but these cells are not auxotrophic for adenosine or other purines. The significant alterations in the control of purine de novo and salvage metabolism caused by the defect in adenylosuccinate synthetase are mediated by the resulting increased levels of guanosine necleotides.
AB - The isolation and characterization of a mutant murine T‐cell lymphoma (S49) with altered purine metabolism is described. This mutant, AU‐100, was isolated from a mutagenized populatio of S49 cells by virtue of its resistance to 0.1 mM 6‐azauridine in semisolid agarose. The AU‐100 cells are resistant to adenosine mediated cytotoxicity but are extraordinarily sensitive to killing by guanosine. High performance liquid chromatography of AU‐100 cells extracts has demonstrated that intracellular levels of GTP, IMP, and GMP are all elevated about 3‐fold over those levels found in wild type cells. The AU‐100 cells also contain an elevated intracellular level of pyrophosphoribosylphosphate (PPriboseP), which as in wild type cells is diminished by incubation of AU‐100 cells with adenosine. However AU‐100 cells synthesize purines de novo at a rate less than 35% of that found in wild type cells. In other growth rate experiments, the AU‐100 cell line was shown to be resistant to 6‐thioguanine and 6‐mercaptopurine. Levels of hypoxanthine‐guanine phosphoribosyltransferase (HGPRTase) measured in AU‐100 cell extracts, however, are 50‐66% greater than those levels of HGPRTase found in wild type cell extracts. Nevertheless this mutant S49 cell line cannot efficiently incorporate labeled hypoxanthine into nucleotides since the salvage enzyme HGPRTase is inhibited in vivo. The AU‐100 cell line was found to be 80% deficient in adenylosuccinate synthetase, but these cells are not auxotrophic for adenosine or other purines. The significant alterations in the control of purine de novo and salvage metabolism caused by the defect in adenylosuccinate synthetase are mediated by the resulting increased levels of guanosine necleotides.
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U2 - 10.1002/jcp.1040990115
DO - 10.1002/jcp.1040990115
M3 - Article
C2 - 222775
AN - SCOPUS:0018342208
SN - 0021-9541
VL - 99
SP - 139
EP - 151
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 1
ER -