The utilization of dCTP derived from de novo synthesis through ribonucleotide reductase in exponentially growing CCRF-CEM cells was compared with the metabolic fate of dCTP produced by the salvage pathway. Exogenous dCyd was not effectively incorporated into replicating DNA; instead, dCTP derived from ribonucleotide reductase (labeled by [5-H]Cyd) was the main precursor for that purpose, apparently because of functional compartmentation of the dCTP pool in these cells. Studies of the metabolic route of incorporation of exogenous [5-H]dCyd into DNA of growing CCRF-CEM cells demonstrated that it was mainly incorporated through the DNA repair pathway. Incorporation of [5-H]dCyd into DNA of synchronized cell populations was maximal in G cells, whereas [H]dThd incorporation occurred predominantly in S phase cells. When cellular DNA was density labeled by incubation with BrdUrd, repaired DNA, which was less dense than replicated DNA, was preferentially labeled by [5-H]dCyd. In contrast, replicated DNA was labeled by both [H]dThd and [5-H]Cyd. The DNA-damaging agents methylmethanesulfonate, ultraviolet irradiation, and -irradiation inhibited [H]dThd incorporation, whereas they stimulated the accumulation of [5-H]dCyd in DNA. Based on these results, we propose that the dCTP pool is functionally compartmentalized in growing CCRF-CEM cells. dCTP derived from the salvage pathway is utilized predominantly for DNA repair, whereas the de novo pathway supplies dCTP for DNA replication.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				S. Cardoen, E. Van Den Neste, C. Smal, J.-F. Rosier, A. Delacauw, A. Ferrant, G. Van den Berghe, and F. Bontemps Resistance to 2-Chloro-2'-deoxyadenosine of the Human B-cell Leukemia Cell Line EHEB Clin. Cancer Res., November 1, 2001; 7(11): 3559 - 3566. [Abstract] [Full Text] [PDF]

				J. W. Taub, X. Huang, Y. Ge, J. A. Dutcher, M. L. Stout, R. M. Mohammad, Y. Ravindranath, and L. H. Matherly Cystathionine-{beta}-Synthase cDNA Transfection Alters the Sensitivity and Metabolism of 1-{beta}-D-Arabinofuranosylcytosine in CCRF-CEM Leukemia Cells in Vitro and in Vivo: A Model of Leukemia in Down Syndrome Cancer Res., November 1, 2000; 60(22): 6421 - 6426. [Abstract] [Full Text]

				T. G. Petrakis, E. Ktistaki, L. Wang, S. Eriksson, and I. Talianidis Cloning and Characterization of Mouse Deoxyguanosine Kinase. EVIDENCE FOR A CYTOPLASMIC ISOFORM J. Biol. Chem., August 27, 1999; 274(35): 24726 - 24730. [Abstract] [Full Text] [PDF]

				L. Lall and R. L. Davidson Sequence-Directed Base Mispairing in Human Oncogenes Mol. Cell. Biol., August 1, 1998; 18(8): 4659 - 4669. [Abstract] [Full Text]

				M. Johansson, S. Brismar, and A. Karlsson Human deoxycytidine kinase is located in the cell nucleus PNAS, October 28, 1997; 94(22): 11941 - 11945. [Abstract] [Full Text] [PDF]

				H. Iwasaki, P. Huang, M. J. Keating, and W. Plunkett Differential Incorporation of Ara-C, Gemcitabine, and Fludarabine Into Replicating and Repairing DNA in Proliferating Human Leukemia Cells Blood, July 1, 1997; 90(1): 270 - 278. [Abstract] [Full Text] [PDF]

				V. Bianchi, S. Borella, C. Rampazzo, P. Ferraro, F. Calderazzo, L. C. Bianchi, S. Skog, and P. Reichard Cell Cycle-dependent Metabolism of Pyrimidine Deoxynucleoside Triphosphates in CEM Cells J. Biol. Chem., June 27, 1997; 272(26): 16118 - 16124. [Abstract] [Full Text] [PDF]