Loss of the catalytic subunit of the DNA-dependent protein kinase in DNA double-strand-break-repair mutant mammalian cells
- Los Alamos National Lab., NM (United States)
- Tottori Univ., Yonago (Japan)
- Univ. of Colorado, Boulder, CO (United States)
The DNA-dependent protein kinase (DNA-PK) consists of three polypeptide components: Ku-70, Ku-80, and an {approx}350-kDa catalytic subunit (p350). The gene encoding the Ku-80 subunit is identical to the x-ray-sensitive group 5 complementing gene XRCC5. Expression of the Ku-80 cDNA rescues both DNA double-strand break (DSB) repair and V(D)J recombination in group 5 mutant cells. The involvement of Ku-80 in these processes suggests that the underlying defect in these mutant cells may be disruption of the DNA-PK holoenzyme. In this report we show that the p350 kinase subunit is deleted in cells derived from the severe combined immunodeficiency mouse and in the Chinese hamster ovary cell line V-3, both of which are defective in DSB repair and V(D)J recombination. A centromeric fragment of human chromosome 8 that complements the scid defect also restores p350 protein expression and rescues in vitro DNA-PK activity. These data suggest the scid gene may encode the p350 protein or regulate its expression and are consistent with a model whereby DNA-PK is a critical component of the DSB-repair pathway. 38 refs., 3 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 61832
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 92, Issue 8; Other Information: PBD: 11 Apr 1995
- Country of Publication:
- United States
- Language:
- English
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