A DNA-PKcs mutation in a radiosensitive T-B- SCID patient inhibits Artemis activation and nonhomologous end-joining

Mirjam van der Burg, Hanna Ijspeert, Nicole Verkaik, T (Tuba) Turul, WW Wiegant, K Morotomi-Yano, PO Mari, I Tezcan, DJ Chen, MZ Zdzienicka, Jacques Dongen, Dik van Gent

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Abstract

Radiosensitive T-B- severe combined immunodeficiency (RS-SCID) is caused by defects in the nonhomologous end-joining (NHEJ) DNA repair pathway, which results in failure of functional V(D)J recombination. Here we have identified the first human RS-SCID patient to our knowledge with a DNA-PKcs missense mutation (L3062R). The causative mutation did not affect the kinase activity or DNA end-binding capacity of DNA-PKcs itself; rather, the presence of long P-nucleotide stretches in the immunoglobulin coding joints indicated that it caused insufficient Artemis activation, something that is dependent on Artemis interaction with autophosphorylated DNA-PKcs. Moreover, overall end-joining activity was hampered, suggesting that Artemis-independent DNA-PKcs functions were also inhibited. This study demonstrates that the presence of DNA-PKcs kinase activity is not sufficient to rule out a defect in this gene during diagnosis and treatment of RS-SCID patients. Further, the data suggest that residual DNA-PKcs activity is indispensable in humans.
Original languageUndefined/Unknown
Pages (from-to)91-98
Number of pages8
JournalJournal of Clinical Investigation
Volume119
Issue number1
DOIs
Publication statusPublished - 2009

Research programs

  • EMC MGC-01-12-03
  • EMC MM-02-72-01

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