A DNA-PKcs mutation in a radiosensitive T-B- SCID patient inhibits Artemis activation and nonhomologous end-joining.
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.
van der Burg
Mirjam
M
Department of Immunology, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Ijspeert
Hanna
H
Verkaik
Nicole S
NS
Turul
Tuba
T
Wiegant
Wouter W
WW
Morotomi-Yano
Keiko
K
Mari
Pierre-Olivier
PO
Tezcan
Ilhan
I
Chen
David J
DJ
Zdzienicka
Malgorzata Z
MZ
van Dongen
Jacques J M
JJ
van Gent
Dik C
DC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002675:Child, Preschool; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism; D004252:DNA Mutational Analysis; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins; D004720:Endonucleases; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology / Q000528:radiation effects; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D010375:Pedigree; D011836:Radiation Tolerance; D011995:Recombination, Genetic; D016415:Sequence Alignment; D016511:Severe Combined Immunodeficiency / Q000175:diagnosis / Q000235:genetics*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; C426344:DCLRE1C protein, human; D004720:Endonucleases; D011088:DNA Ligases; D000072481:DNA Ligase ATP