title: The contribution of CMP kinase to the efficiency of DNA repair.
abstract: Cellular supply of deoxynucleoside triphosphates (dNTPs) is crucial for DNA replication and repair. In this study, we investigated the role of CMP/UMP kinase (CMPK), an enzyme catalyzes CDP formation, in DNA repair. Knockdown of CMPK delays DNA repair during recovery from UV damage in serum-deprived cells but not in the cells without serum deprivation. Exogenous supply of cytidine or deoxycytidine facilitates DNA repair dependent on CMPK in serum-deprived cells, suggesting that the synthesis of dCDP or CDP determines the rate of repair. However, CMPK knockdown does not affect the steady state level of dCTP in serum-deprived cells. We then found the localization of CMPK at DNA damage sites and its complex formation with Tip60 and ribonucleotide reductase. Our analysis demonstrated that the N-terminal 32-amino-acid of CMPK is required for its recruitment to DNA damage sites in a Tip60-dependent manner. Re-expression of wild-type but not N-terminus deleted CMPK restores the efficiency of DNA repair in CMPK knockdown cells. We proposed that site-specific dCDP formation via CMPK provides a means to facilitate DNA repair in serum-deprived cells.
authors: a Graduate Institute of Biochemistry and Molecular Biology; College of Medicine ; National Taiwan University ; Taipei , Taiwan (R.O.C.).
authors: Ning
authors: N
authors: Tsao
authors: Ming-Hsiang
authors: MH
authors: Lee
authors: Wei
authors: W
authors: Zhang
authors: Yung-Chi
authors: YC
authors: Cheng
authors: Zee-Fen
authors: ZF
authors: Chang
mesh_terms: D016895:Culture Media, Serum-Free; D003562:Cytidine / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair / Q000528:radiation effects; D003845:Deoxycytosine Nucleotides / Q000378:metabolism; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D061986:MCF-7 Cells; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000378:metabolism; D009703:Nucleoside-Phosphate Kinase / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D016895:Culture Media, Serum-Free; D003845:Deoxycytosine Nucleotides; D046912:Multiprotein Complexes; C024107:2'-deoxycytidine 5'-triphosphate; D003562:Cytidine; C019979:cytidylate kinase; D009703:Nucleoside-Phosphate Kinase
keywords: CMP/UMP kinase; DNA repair; Tip60; UV irradiation; dNTP; dNTP, deoxynucleoside triphosphates; CMPK, CMP/UMP kinase; RNR, ribonucleotide reductase; 6-4 pp, (6-4) photoproduct; R1C, C-terminal fragment of R1 subunit of RNR; recruitment to DNA damage sites; ribonucleotide reductase; serum deprivation