Thymidine Kinase 1 Deficient Cells Show Increased Survival Rate After UV-Induced DNA Damage

Abstract

Balanced deoxynucleotide pools are known to be important for correct DNA repair, and deficiency for some of the central enzymes in deoxynucleotide metabolism can cause imbalanced pools, which in turn can lead to mutagenesis and cell death. Here we show that cells deficient for the thymidine salvage enzyme thymidine kinase 1 (TK1) are more resistant to UV-induced DNA damage than TK1 positive cells although they have thymidine triphosphate (dTTP) levels of only half the size of control cells. Our results suggest that higher thymidine levels in the TK- cells caused by defect thymidine salvage to dTTP protects against UV irradiation.

Keywords:

• Thymidine kinase 1
• survival
• DNA damage
• UV
• dTTP pools

Acknowledgments

We would like to thank Chiara Rampazzo for providing the HOS cells.

Present address for T. S.: NNF Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.