Two thymidine kinases and one multisubstrate deoxyribonucleoside kinase salvage DNA precursors in Arabidopsis thaliana

Anders Ranegaard Anders Ranegaard Clausen, Lenart Girandon, Ashfaq Ali, Wolfgang Knecht, Elzbieta Rozpedowska, Michael Paolo Sandrini, Erik Andreasson, Birgitte Munch-Petersen, Jure Piskur

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    Deoxyribonucleotides are the building blocks of DNA and can be synthesized via de novo and salvage pathways. Deoxyribonucleoside kinases (EC salvage deoxyribonucleosides by transfer of a phosphate group to the 5' of a deoxyribonucleoside. This salvage pathway is well characterized in mammals, but in contrast, little is known about how plants salvage deoxyribonucleosides. We show that during salvage, deoxyribonucleosides can be phosphorylated by extracts of Arabidopsis thaliana into corresponding monophosphate compounds with an unexpected preference for purines over pyrimidines. Deoxyribonucleoside kinase activities were present in all tissues during all growth stages. In the A. thaliana genome, we identified two types of genes that could encode enzymes which are involved in the salvage of deoxyribonucleosides. Thymidine kinase activity was encoded by two thymidine kinase 1 (EC genes (AtTK1a and AtTK1b). Deoxyadenosine, deoxyguanosine and deoxycytidine kinase activities were encoded by a single AtdNK gene. T-DNA insertion lines of AtTK1a and AtTK1b mutant genes had normal growth, although AtTK1a AtTK1b double mutants died at an early stage, which indicates that AtTK1a and AtTK1b catalyze redundant reactions. The results obtained in the present study suggest a crucial role for the salvage of thymidine during early plant development.
    TidsskriftF E B S Journal
    Udgave nummer20
    Sider (fra-til)3889-3897
    Antal sider9
    StatusUdgivet - jan. 2012


    • Arabidopsis
    • nucleoside nucleotide metabolism
    • deoxyribonucleoside kinase
    • thymidine kinase

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