A novel splice variant of the DNA-PKcs gene is associated with clinical and cellular radiosensitivity in a patient with xeroderma pigmentosum.
| Autor: | Abbaszadeh F; Brunel Institute of Cancer Genetics and Pharmacogenomics, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge UB8 3PH, Middlesex, UK., Clingen PH, Arlett CF, Plowman PN, Bourton EC, Themis M, Makarov EM, Newbold RF, Green MH, Parris CN |
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| Jazyk: | angličtina |
| Zdroj: | Journal of medical genetics [J Med Genet] 2010 Mar; Vol. 47 (3), pp. 176-81. Date of Electronic Publication: 2009 Sep 24. |
| DOI: | 10.1136/jmg.2009.068866 |
| Abstrakt: | Background: Radiotherapy-induced DNA double-strand breaks (DSBs) are critical cytotoxic lesions. Inherited defects in DNA DSB repair pathways lead to hypersensitivity to ionising radiation, immunodeficiency and increased cancer incidence. A patient with xeroderma pigmentosum complementation group C, with a scalp angiosarcoma, exhibited dramatic clinical radiosensitivity following radiotherapy, resulting in death. A fibroblast cell line from non-affected skin (XP14BRneo17) was hypersensitive to ionising radiation and defective in DNA DSB repair. Aim: To determine the genetic defect causing cellular radiation hypersensitivity in XP14BRneo17 cells. Methods: Functional genetic complementation whereby copies of human chromosomes containing genes involved in DNA DSB repair (chromosomes 2, 5, 8 10, 13 and 22) were individually transferred to XP14BRneo17 cells in an attempt to correct the radiation hypersensitivity. Clonogenic survival assays and gamma-H2AX immunofluorescence were conducted to measure radiation sensitivity and repair of DNA DSBs. DNA sequencing of defective DNA repair genes was performed. Results: Transfer of chromosome 8 (location of DNA-PKcs gene) and transfection of a mammalian expression construct containing the DNA-PKcs cDNA restored normal ionising radiation sensitivity and repair of DNA DSBs in XP14BRneo17 cells. DNA sequencing of the DNA-PKcs coding region revealed a 249-bp deletion (between base pairs 3656 and 3904) encompassing exon 31 of the gene. Conclusion: We provide evidence of a novel splice variant of the DNA-PKcs gene associated with radiosensitivity in a patient with xeroderma pigmentosum and report the first double mutant in distinct DNA repair pathways being consistent with viability. |
| Databáze: | MEDLINE |
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