A novel splice variant of the DNA-PKcs gene is associated with clinical and cellular radiosensivity in a patient with xeroderma pigmentosum

Abbaszadeh, Fatemah, Clingen, Peter H., Arlett, Colin F., Plowman, P.N, Bourton, E.C, Themis, M., Makarov, E.M., Newbold, R.F, Green, M H and Parris, C.N. (2010) A novel splice variant of the DNA-PKcs gene is associated with clinical and cellular radiosensivity in a patient with xeroderma pigmentosum. Journal of Medical Genetics, 47 (3). pp. 176-181. ISSN 00222593

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Abstract

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 g-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 DNAPKcs 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.

Item Type: Article
Additional Information: GDSC306A
Schools and Departments: School of Life Sciences > Sussex Centre for Genome Damage and Stability
Subjects: Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics
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Depositing User: Gee Wheatley
Date Deposited: 19 Jul 2010
Last Modified: 13 Mar 2017 21:52
URI: http://sro.sussex.ac.uk/id/eprint/2425

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