Abstract
Eukaryotic cells repair DNA double-strand breaks (DSBs) by at least two pathways, homologous recombination (HR) and non-homologous end-joining (NHEJ). Rad54 participates in the first recombinational repair pathway while Ku proteins are involved in NHEJ. To investigate the distinctive as well as redundant roles of these two repair pathways, we analyzed the mutants RAD54(-/-), KU70(-/-) and RAD54(-/-)/KU70(-/-), generated from the chicken B-cell line DT40. We found that the NHEJ pathway plays a dominant role in repairing gamma-radiation-induced DSBs during G1-early S phase while recombinational repair is preferentially used in late S-G2 phase. RAD54(-/-)/KU70(-/-) cells were profoundly more sensitive to gamma-rays than either single mutant, indicating that the two repair pathways are complementary. Spontaneous chromosomal aberrations and cell death were observed in both RAD54(-/-) and RAD54(-/-)/KU70(-/-) cells, with RAD54(-/-)/KU70(-/-) cells exhibiting significantly higher levels of chromosomal aberrations than RAD54(-/-) cells. These observations provide the first genetic evidence that both repair pathways play a role in maintaining chromosomal DNA during the cell cycle.
Full Text
The Full Text of this article is available as a PDF (764.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Baba T. W., Giroir B. P., Humphries E. H. Cell lines derived from avian lymphomas exhibit two distinct phenotypes. Virology. 1985 Jul 15;144(1):139–151. doi: 10.1016/0042-6822(85)90312-5. [DOI] [PubMed] [Google Scholar]
- Benjamin M. B., Potter H., Yandell D. W., Little J. B. A system for assaying homologous recombination at the endogenous human thymidine kinase gene. Proc Natl Acad Sci U S A. 1991 Aug 1;88(15):6652–6656. doi: 10.1073/pnas.88.15.6652. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bezzubova O. Y., Buerstedde J. M. Gene conversion in the chicken immunoglobulin locus: a paradigm of homologous recombination in higher eukaryotes. Experientia. 1994 Mar 15;50(3):270–276. doi: 10.1007/BF01924010. [DOI] [PubMed] [Google Scholar]
- Bezzubova O. Y., Schmidt H., Ostermann K., Heyer W. D., Buerstedde J. M. Identification of a chicken RAD52 homologue suggests conservation of the RAD52 recombination pathway throughout the evolution of higher eukaryotes. Nucleic Acids Res. 1993 Dec 25;21(25):5945–5949. doi: 10.1093/nar/21.25.5945. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bezzubova O., Shinohara A., Mueller R. G., Ogawa H., Buerstedde J. M. A chicken RAD51 homologue is expressed at high levels in lymphoid and reproductive organs. Nucleic Acids Res. 1993 Apr 11;21(7):1577–1580. doi: 10.1093/nar/21.7.1577. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bezzubova O., Silbergleit A., Yamaguchi-Iwai Y., Takeda S., Buerstedde J. M. Reduced X-ray resistance and homologous recombination frequencies in a RAD54-/- mutant of the chicken DT40 cell line. Cell. 1997 Apr 18;89(2):185–193. doi: 10.1016/s0092-8674(00)80198-1. [DOI] [PubMed] [Google Scholar]
- Boulton S. J., Jackson S. P. Identification of a Saccharomyces cerevisiae Ku80 homologue: roles in DNA double strand break rejoining and in telomeric maintenance. Nucleic Acids Res. 1996 Dec 1;24(23):4639–4648. doi: 10.1093/nar/24.23.4639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boulton S. J., Jackson S. P. Saccharomyces cerevisiae Ku70 potentiates illegitimate DNA double-strand break repair and serves as a barrier to error-prone DNA repair pathways. EMBO J. 1996 Sep 16;15(18):5093–5103. [PMC free article] [PubMed] [Google Scholar]
- Buerstedde J. M., Reynaud C. A., Humphries E. H., Olson W., Ewert D. L., Weill J. C. Light chain gene conversion continues at high rate in an ALV-induced cell line. EMBO J. 1990 Mar;9(3):921–927. doi: 10.1002/j.1460-2075.1990.tb08190.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Buerstedde J. M., Takeda S. Increased ratio of targeted to random integration after transfection of chicken B cell lines. Cell. 1991 Oct 4;67(1):179–188. doi: 10.1016/0092-8674(91)90581-i. [DOI] [PubMed] [Google Scholar]
- Cheong N., Wang X., Wang Y., Iliakis G. Loss of S-phase-dependent radioresistance in irs-1 cells exposed to X-rays. Mutat Res. 1994 Jan;314(1):77–85. doi: 10.1016/0921-8777(94)90063-9. [DOI] [PubMed] [Google Scholar]
- Critchlow S. E., Bowater R. P., Jackson S. P. Mammalian DNA double-strand break repair protein XRCC4 interacts with DNA ligase IV. Curr Biol. 1997 Aug 1;7(8):588–598. doi: 10.1016/s0960-9822(06)00258-2. [DOI] [PubMed] [Google Scholar]
- Darroudi F., Natarajan A. T. Cytological characterization of Chinese hamster ovary X-ray-sensitive mutant cells, xrs 5 and xrs 6. II. Induction of sister-chromatid exchanges and chromosomal aberrations by X-rays and UV-irradiation and their modulation by inhibitors of poly(ADP-ribose) synthetase and alpha-polymerase. Mutat Res. 1987 Mar;177(1):149–160. doi: 10.1016/0027-5107(87)90030-3. [DOI] [PubMed] [Google Scholar]
- Essers J., Hendriks R. W., Swagemakers S. M., Troelstra C., de Wit J., Bootsma D., Hoeijmakers J. H., Kanaar R. Disruption of mouse RAD54 reduces ionizing radiation resistance and homologous recombination. Cell. 1997 Apr 18;89(2):195–204. doi: 10.1016/s0092-8674(00)80199-3. [DOI] [PubMed] [Google Scholar]
- Feldmann H., Winnacker E. L. A putative homologue of the human autoantigen Ku from Saccharomyces cerevisiae. J Biol Chem. 1993 Jun 15;268(17):12895–12900. [PubMed] [Google Scholar]
- Fingerhut R., Kiefer J., Otto F. Cell cycle parameters in radiation sensitive strains of Saccharomyces cerevisiae. Mol Gen Genet. 1984;193(1):192–194. doi: 10.1007/BF00327437. [DOI] [PubMed] [Google Scholar]
- Game J. C. DNA double-strand breaks and the RAD50-RAD57 genes in Saccharomyces. Semin Cancer Biol. 1993 Apr;4(2):73–83. [PubMed] [Google Scholar]
- Game J. C., Mortimer R. K. A genetic study of x-ray sensitive mutants in yeast. Mutat Res. 1974 Sep;24(3):281–292. doi: 10.1016/0027-5107(74)90176-6. [DOI] [PubMed] [Google Scholar]
- Gecz J., Pollard H., Consalez G., Villard L., Stayton C., Millasseau P., Khrestchatisky M., Fontes M. Cloning and expression of the murine homologue of a putative human X-linked nuclear protein gene closely linked to PGK1 in Xq13.3. Hum Mol Genet. 1994 Jan;3(1):39–44. doi: 10.1093/hmg/3.1.39. [DOI] [PubMed] [Google Scholar]
- Godwin A. R., Bollag R. J., Christie D. M., Liskay R. M. Spontaneous and restriction enzyme-induced chromosomal recombination in mammalian cells. Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12554–12558. doi: 10.1073/pnas.91.26.12554. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grawunder U., Wilm M., Wu X., Kulesza P., Wilson T. E., Mann M., Lieber M. R. Activity of DNA ligase IV stimulated by complex formation with XRCC4 protein in mammalian cells. Nature. 1997 Jul 31;388(6641):492–495. doi: 10.1038/41358. [DOI] [PubMed] [Google Scholar]
- Gu Y., Jin S., Gao Y., Weaver D. T., Alt F. W. Ku70-deficient embryonic stem cells have increased ionizing radiosensitivity, defective DNA end-binding activity, and inability to support V(D)J recombination. Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):8076–8081. doi: 10.1073/pnas.94.15.8076. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guacci V., Koshland D., Strunnikov A. A direct link between sister chromatid cohesion and chromosome condensation revealed through the analysis of MCD1 in S. cerevisiae. Cell. 1997 Oct 3;91(1):47–57. doi: 10.1016/s0092-8674(01)80008-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jeggo P. A. DNA-PK: at the cross-roads of biochemistry and genetics. Mutat Res. 1997 Jun 9;384(1):1–14. doi: 10.1016/s0921-8777(97)00009-8. [DOI] [PubMed] [Google Scholar]
- Jeggo P. A. Studies on mammalian mutants defective in rejoining double-strand breaks in DNA. Mutat Res. 1990 Jul;239(1):1–16. doi: 10.1016/0165-1110(90)90028-a. [DOI] [PubMed] [Google Scholar]
- Kadyk L. C., Hartwell L. H. Sister chromatids are preferred over homologs as substrates for recombinational repair in Saccharomyces cerevisiae. Genetics. 1992 Oct;132(2):387–402. doi: 10.1093/genetics/132.2.387. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kanaar R., Troelstra C., Swagemakers S. M., Essers J., Smit B., Franssen J. H., Pastink A., Bezzubova O. Y., Buerstedde J. M., Clever B. Human and mouse homologs of the Saccharomyces cerevisiae RAD54 DNA repair gene: evidence for functional conservation. Curr Biol. 1996 Jul 1;6(7):828–838. doi: 10.1016/s0960-9822(02)00606-1. [DOI] [PubMed] [Google Scholar]
- Kemp L. M., Jeggo P. A. Radiation-induced chromosome damage in X-ray-sensitive mutants (xrs) of the Chinese hamster ovary cell line. Mutat Res. 1986 Nov;166(3):255–263. doi: 10.1016/0167-8817(86)90025-8. [DOI] [PubMed] [Google Scholar]
- Kozak M. Adherence to the first-AUG rule when a second AUG codon follows closely upon the first. Proc Natl Acad Sci U S A. 1995 Mar 28;92(7):2662–2666. doi: 10.1073/pnas.92.7.2662. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kozak M. Bifunctional messenger RNAs in eukaryotes. Cell. 1986 Nov 21;47(4):481–483. doi: 10.1016/0092-8674(86)90609-4. [DOI] [PubMed] [Google Scholar]
- Lee S. E., Mitchell R. A., Cheng A., Hendrickson E. A. Evidence for DNA-PK-dependent and -independent DNA double-strand break repair pathways in mammalian cells as a function of the cell cycle. Mol Cell Biol. 1997 Mar;17(3):1425–1433. doi: 10.1128/mcb.17.3.1425. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Li Z., Otevrel T., Gao Y., Cheng H. L., Seed B., Stamato T. D., Taccioli G. E., Alt F. W. The XRCC4 gene encodes a novel protein involved in DNA double-strand break repair and V(D)J recombination. Cell. 1995 Dec 29;83(7):1079–1089. doi: 10.1016/0092-8674(95)90135-3. [DOI] [PubMed] [Google Scholar]
- Lim D. S., Hasty P. A mutation in mouse rad51 results in an early embryonic lethal that is suppressed by a mutation in p53. Mol Cell Biol. 1996 Dec;16(12):7133–7143. doi: 10.1128/mcb.16.12.7133. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Liu N., Lamerdin J. E., Tebbs R. S., Schild D., Tucker J. D., Shen M. R., Brookman K. W., Siciliano M. J., Walter C. A., Fan W. XRCC2 and XRCC3, new human Rad51-family members, promote chromosome stability and protect against DNA cross-links and other damages. Mol Cell. 1998 May;1(6):783–793. doi: 10.1016/s1097-2765(00)80078-7. [DOI] [PubMed] [Google Scholar]
- Martin S. J., Reutelingsperger C. P., McGahon A. J., Rader J. A., van Schie R. C., LaFace D. M., Green D. R. Early redistribution of plasma membrane phosphatidylserine is a general feature of apoptosis regardless of the initiating stimulus: inhibition by overexpression of Bcl-2 and Abl. J Exp Med. 1995 Nov 1;182(5):1545–1556. doi: 10.1084/jem.182.5.1545. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Michaelis C., Ciosk R., Nasmyth K. Cohesins: chromosomal proteins that prevent premature separation of sister chromatids. Cell. 1997 Oct 3;91(1):35–45. doi: 10.1016/s0092-8674(01)80007-6. [DOI] [PubMed] [Google Scholar]
- Milne G. T., Jin S., Shannon K. B., Weaver D. T. Mutations in two Ku homologs define a DNA end-joining repair pathway in Saccharomyces cerevisiae. Mol Cell Biol. 1996 Aug;16(8):4189–4198. doi: 10.1128/mcb.16.8.4189. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mimori T., Hardin J. A. Mechanism of interaction between Ku protein and DNA. J Biol Chem. 1986 Aug 5;261(22):10375–10379. [PubMed] [Google Scholar]
- Mimori T., Ohosone Y., Hama N., Suwa A., Akizuki M., Homma M., Griffith A. J., Hardin J. A. Isolation and characterization of cDNA encoding the 80-kDa subunit protein of the human autoantigen Ku (p70/p80) recognized by autoantibodies from patients with scleroderma-polymyositis overlap syndrome. Proc Natl Acad Sci U S A. 1990 Mar;87(5):1777–1781. doi: 10.1073/pnas.87.5.1777. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mizuta R., LaSalle J. M., Cheng H. L., Shinohara A., Ogawa H., Copeland N., Jenkins N. A., Lalande M., Alt F. W. RAB22 and RAB163/mouse BRCA2: proteins that specifically interact with the RAD51 protein. Proc Natl Acad Sci U S A. 1997 Jun 24;94(13):6927–6932. doi: 10.1073/pnas.94.13.6927. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore J. K., Haber J. E. Cell cycle and genetic requirements of two pathways of nonhomologous end-joining repair of double-strand breaks in Saccharomyces cerevisiae. Mol Cell Biol. 1996 May;16(5):2164–2173. doi: 10.1128/mcb.16.5.2164. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Morita T., Yoshimura Y., Yamamoto A., Murata K., Mori M., Yamamoto H., Matsushiro A. A mouse homolog of the Escherichia coli recA and Saccharomyces cerevisiae RAD51 genes. Proc Natl Acad Sci U S A. 1993 Jul 15;90(14):6577–6580. doi: 10.1073/pnas.90.14.6577. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moynahan M. E., Jasin M. Loss of heterozygosity induced by a chromosomal double-strand break. Proc Natl Acad Sci U S A. 1997 Aug 19;94(17):8988–8993. doi: 10.1073/pnas.94.17.8988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Muris D. F., Vreeken K., Carr A. M., Broughton B. C., Lehmann A. R., Lohman P. H., Pastink A. Cloning the RAD51 homologue of Schizosaccharomyces pombe. Nucleic Acids Res. 1993 Sep 25;21(19):4586–4591. doi: 10.1093/nar/21.19.4586. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Muris D. F., Vreeken K., Carr A. M., Murray J. M., Smit C., Lohman P. H., Pastink A. Isolation of the Schizosaccharomyces pombe RAD54 homologue, rhp54+, a gene involved in the repair of radiation damage and replication fidelity. J Cell Sci. 1996 Jan;109(Pt 1):73–81. doi: 10.1242/jcs.109.1.73. [DOI] [PubMed] [Google Scholar]
- Nussenzweig A., Chen C., da Costa Soares V., Sanchez M., Sokol K., Nussenzweig M. C., Li G. C. Requirement for Ku80 in growth and immunoglobulin V(D)J recombination. Nature. 1996 Aug 8;382(6591):551–555. doi: 10.1038/382551a0. [DOI] [PubMed] [Google Scholar]
- Ouyang H., Nussenzweig A., Kurimasa A., Soares V. C., Li X., Cordon-Cardo C., Li W. h., Cheong N., Nussenzweig M., Iliakis G. Ku70 is required for DNA repair but not for T cell antigen receptor gene recombination In vivo. J Exp Med. 1997 Sep 15;186(6):921–929. doi: 10.1084/jem.186.6.921. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Saeki T., Machida I., Nakai S. Genetic control of diploid recovery after gamma-irradiation in the yeast Saccharomyces cerevisiae. Mutat Res. 1980 Dec;73(2):251–265. doi: 10.1016/0027-5107(80)90192-x. [DOI] [PubMed] [Google Scholar]
- Savatier P., Lapillonne H., van Grunsven L. A., Rudkin B. B., Samarut J. Withdrawal of differentiation inhibitory activity/leukemia inhibitory factor up-regulates D-type cyclins and cyclin-dependent kinase inhibitors in mouse embryonic stem cells. Oncogene. 1996 Jan 18;12(2):309–322. [PubMed] [Google Scholar]
- Scully R., Chen J., Plug A., Xiao Y., Weaver D., Feunteun J., Ashley T., Livingston D. M. Association of BRCA1 with Rad51 in mitotic and meiotic cells. Cell. 1997 Jan 24;88(2):265–275. doi: 10.1016/s0092-8674(00)81847-4. [DOI] [PubMed] [Google Scholar]
- Sharan S. K., Morimatsu M., Albrecht U., Lim D. S., Regel E., Dinh C., Sands A., Eichele G., Hasty P., Bradley A. Embryonic lethality and radiation hypersensitivity mediated by Rad51 in mice lacking Brca2. Nature. 1997 Apr 24;386(6627):804–810. doi: 10.1038/386804a0. [DOI] [PubMed] [Google Scholar]
- Shinohara A., Ogawa H., Matsuda Y., Ushio N., Ikeo K., Ogawa T. Cloning of human, mouse and fission yeast recombination genes homologous to RAD51 and recA. Nat Genet. 1993 Jul;4(3):239–243. doi: 10.1038/ng0793-239. [DOI] [PubMed] [Google Scholar]
- Shinohara A., Ogawa T. Homologous recombination and the roles of double-strand breaks. Trends Biochem Sci. 1995 Oct;20(10):387–391. doi: 10.1016/s0968-0004(00)89085-4. [DOI] [PubMed] [Google Scholar]
- Smider V., Rathmell W. K., Lieber M. R., Chu G. Restoration of X-ray resistance and V(D)J recombination in mutant cells by Ku cDNA. Science. 1994 Oct 14;266(5183):288–291. doi: 10.1126/science.7939667. [DOI] [PubMed] [Google Scholar]
- Sonoda E., Sasaki M. S., Buerstedde J. M., Bezzubova O., Shinohara A., Ogawa H., Takata M., Yamaguchi-Iwai Y., Takeda S. Rad51-deficient vertebrate cells accumulate chromosomal breaks prior to cell death. EMBO J. 1998 Jan 15;17(2):598–608. doi: 10.1093/emboj/17.2.598. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stamato T. D., Dipatri A., Giaccia A. Cell-cycle-dependent repair of potentially lethal damage in the XR-1 gamma-ray-sensitive Chinese hamster ovary cell. Radiat Res. 1988 Aug;115(2):325–333. [PubMed] [Google Scholar]
- Stürzbecher H. W., Donzelmann B., Henning W., Knippschild U., Buchhop S. p53 is linked directly to homologous recombination processes via RAD51/RecA protein interaction. EMBO J. 1996 Apr 15;15(8):1992–2002. [PMC free article] [PubMed] [Google Scholar]
- Sugawara H., Kurosaki M., Takata M., Kurosaki T. Genetic evidence for involvement of type 1, type 2 and type 3 inositol 1,4,5-trisphosphate receptors in signal transduction through the B-cell antigen receptor. EMBO J. 1997 Jun 2;16(11):3078–3088. doi: 10.1093/emboj/16.11.3078. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taccioli G. E., Gottlieb T. M., Blunt T., Priestley A., Demengeot J., Mizuta R., Lehmann A. R., Alt F. W., Jackson S. P., Jeggo P. A. Ku80: product of the XRCC5 gene and its role in DNA repair and V(D)J recombination. Science. 1994 Sep 2;265(5177):1442–1445. doi: 10.1126/science.8073286. [DOI] [PubMed] [Google Scholar]
- Takata M., Kurosaki T. A role for Bruton's tyrosine kinase in B cell antigen receptor-mediated activation of phospholipase C-gamma 2. J Exp Med. 1996 Jul 1;184(1):31–40. doi: 10.1084/jem.184.1.31. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Takeda S., Masteller E. L., Thompson C. B., Buerstedde J. M. RAG-2 expression is not essential for chicken immunoglobulin gene conversion. Proc Natl Acad Sci U S A. 1992 May 1;89(9):4023–4027. doi: 10.1073/pnas.89.9.4023. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tashiro S., Kotomura N., Shinohara A., Tanaka K., Ueda K., Kamada N. S phase specific formation of the human Rad51 protein nuclear foci in lymphocytes. Oncogene. 1996 May 16;12(10):2165–2170. [PubMed] [Google Scholar]
- Teo S. H., Jackson S. P. Identification of Saccharomyces cerevisiae DNA ligase IV: involvement in DNA double-strand break repair. EMBO J. 1997 Aug 1;16(15):4788–4795. doi: 10.1093/emboj/16.15.4788. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thompson L. H. Evidence that mammalian cells possess homologous recombinational repair pathways. Mutat Res. 1996 Jun 12;363(2):77–88. doi: 10.1016/0921-8777(96)00008-0. [DOI] [PubMed] [Google Scholar]
- Tsuzuki T., Fujii Y., Sakumi K., Tominaga Y., Nakao K., Sekiguchi M., Matsushiro A., Yoshimura Y., MoritaT Targeted disruption of the Rad51 gene leads to lethality in embryonic mice. Proc Natl Acad Sci U S A. 1996 Jun 25;93(13):6236–6240. doi: 10.1073/pnas.93.13.6236. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Uckun F. M., Waddick K. G., Mahajan S., Jun X., Takata M., Bolen J., Kurosaki T. BTK as a mediator of radiation-induced apoptosis in DT-40 lymphoma B cells. Science. 1996 Aug 23;273(5278):1096–1100. doi: 10.1126/science.273.5278.1096. [DOI] [PubMed] [Google Scholar]
- Weaver D. T. What to do at an end: DNA double-strand-break repair. Trends Genet. 1995 Oct;11(10):388–392. doi: 10.1016/s0168-9525(00)89121-0. [DOI] [PubMed] [Google Scholar]
- Wilson T. E., Grawunder U., Lieber M. R. Yeast DNA ligase IV mediates non-homologous DNA end joining. Nature. 1997 Jul 31;388(6641):495–498. doi: 10.1038/41365. [DOI] [PubMed] [Google Scholar]
- Yamamoto A., Taki T., Yagi H., Habu T., Yoshida K., Yoshimura Y., Yamamoto K., Matsushiro A., Nishimune Y., Morita T. Cell cycle-dependent expression of the mouse Rad51 gene in proliferating cells. Mol Gen Genet. 1996 Apr 24;251(1):1–12. doi: 10.1007/BF02174338. [DOI] [PubMed] [Google Scholar]
- Yaneva M., Kowalewski T., Lieber M. R. Interaction of DNA-dependent protein kinase with DNA and with Ku: biochemical and atomic-force microscopy studies. EMBO J. 1997 Aug 15;16(16):5098–5112. doi: 10.1093/emboj/16.16.5098. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zdzienicka M. Z. Mammalian mutants defective in the response to ionizing radiation-induced DNA damage. Mutat Res. 1995 May;336(3):203–213. doi: 10.1016/0921-8777(95)00003-3. [DOI] [PubMed] [Google Scholar]
- Zhu C., Bogue M. A., Lim D. S., Hasty P., Roth D. B. Ku86-deficient mice exhibit severe combined immunodeficiency and defective processing of V(D)J recombination intermediates. Cell. 1996 Aug 9;86(3):379–389. doi: 10.1016/s0092-8674(00)80111-7. [DOI] [PubMed] [Google Scholar]
- Zou H., Rothstein R. Holliday junctions accumulate in replication mutants via a RecA homolog-independent mechanism. Cell. 1997 Jul 11;90(1):87–96. doi: 10.1016/s0092-8674(00)80316-5. [DOI] [PubMed] [Google Scholar]