Defective DNA-dependent protein kinase activity is linked to V(D)J recombination and DNA repair defects associated with the murine scid mutation.
Murine cells homozygous for the severe combined immune deficiency mutation (scid) and V3 mutant hamster cells fall into the same complementation group and show similar defects in V(D)J recombination and DNA double-stranded break repair. Here we show that both cell types lack DNA-dependent protein kinase (DNA-PK) activity owing to defects in DNA-PKcs, the catalytic subunit of this enzyme. Furthermore, we demonstrate that yeast artificial chromosomes containing the DNA-PKcs gene complement both the DNA repair and recombination deficiencies of V3 cells, and we conclude that DNA-PKcs is encoded by the XRCC7 gene. As DNA-PK binds to DNA ends and is activated by these structures, our findings provide novel insights into V(D)J recombination and DNA repair processes.
Blunt
T
T
Wellcome/Cancer Research Campaign Institute, Cambridge University, England.
Finnie
N J
NJ
Taccioli
G E
GE
Smith
G C
GC
Demengeot
J
J
Gottlieb
T M
TM
Mizuta
R
R
Varghese
A J
AJ
Alt
F W
FW
Jeggo
P A
PA
Jackson
S P
SP
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells / Q000528:radiation effects; D002457:Cell Extracts / Q000737:chemistry; D002874:Chromosome Mapping; D018244:Chromosomes, Artificial, Yeast / Q000235:genetics; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D004260:DNA Repair / Q000235:genetics*; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D005720:Gamma Rays; D005816:Genetic Complementation Test; D007135:Immunoglobulin Variable Region / Q000235:genetics; D051379:Mice; D016513:Mice, SCID; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D011836:Radiation Tolerance / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics*; D016511:Severe Combined Immunodeficiency / Q000235:genetics*
D002457:Cell Extracts; D004268:DNA-Binding Proteins; D007135:Immunoglobulin Variable Region; D004247:DNA; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases