DNA-dependent protein kinase activity is absent in xrs-6 cells: implications for site-specific recombination and DNA double-strand break repair - PubMed (original) (raw)

DNA-dependent protein kinase activity is absent in xrs-6 cells: implications for site-specific recombination and DNA double-strand break repair

N J Finnie et al. Proc Natl Acad Sci U S A. 1995.

Abstract

DNA-dependent protein kinase (DNA-PK) is a nuclear serine/threonine protein kinase composed of a catalytic subunit called p350 and a DNA binding component termed Ku. Ku consists of two tightly associated polypeptides of approximately 70 kDa and 80 kDa (Ku80). An intriguing feature of DNA-PK is that it binds to DNA ends and other discontinuities in DNA and requires these structures for its activation. This suggests that DNA-PK may function in DNA repair and/or recombination. Consistent with this, Ku DNA binding activity was shown recently to be absent in extracts of hamster xrs-6 cells, which are defective in DNA double-strand (ds) break repair and V(D)J recombination. Furthermore, xrs-6 cells are complemented by expression of the Ku80 cDNA. To date, DNA-PK activity has been demonstrated unequivocally only in extracts of primate cells. Here, we describe an assay that can detect DNA-PK activity in extracts of mouse, hamster, Xenopus, and Drosophila cells. Using this assay, we find that xrs-6 cells completely lack DNA-PK activity. By contrast, xrs-6 derivatives complemented by human chromosome fragments bearing the Ku80 gene have restored both the DNA end binding and kinase activities associated with DNA-PK. Finally, we show that xrs-6 extracts are complemented biochemically by purified Ku. Our findings indicate that the xrs-6 defects are direct consequences of the mutation in Ku80 and implicate DNA-PK in recombination and DNA repair processes.

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References

1. J Biol Chem. 1993 May 15;268(14):10440-7 - PubMed
1. Cell. 1993 Jan 15;72(1):131-42 - PubMed
1. Trends Biochem Sci. 1994 Nov;19(11):500-3 - PubMed
1. Mol Cell Biol. 1990 Dec;10(12):6472-81 - PubMed
1. In Vitro. 1977 Sep;13(9):557-63 - PubMed

DNA-dependent protein kinase activity is absent in xrs-6 cells: implications for site-specific recombination and DNA double-strand break repair - PubMed (original) (raw)