Scientific background: |
XRCC5(X-ray Repair,Complementing Defective ,In Chinese Hamster, 5), also known as Ku80 or Ku86, is a protein that in humans, is encoded by the XRCC5 gene. The XRCC5 gene encodes the 80-kD subunit of the Ku autoantigen, a heterodimer which contributes to genomic integrity through its ability to bind DNA double-strand breaks and facilitate repair by the nonhomologous end joining (NHEJ) pathway. The XRCC5 gene is mapped to 2q35. Human colon cancer cells heterozygous for Ku86 are haploinsufficient with an increase in polyploid cells, a reduction in cell proliferation, elevated p53 levels, and a slight hypersensitivity to ionizing radiation. Functional inactivation of the second Ku86 allele results in cells with a drastically reduced doubling time. The Ku86 locus is essential in human somatic tissue culture cells by experiments demonstration. A rare microsatellite polymorphism in XRCC5 is associated with cancer in patients of varying radiosensitivity. |
References: |
1. Blunt, T., Taccioli, G. E., Priestley, A., Hafezparast, M., McMillan, T., Liu, J., Cole, C. C., White, J., Alt, F. W., Jackson, S. P., Schurr, E., Lehmann, A. R., Jeggo, P. A. A YAC contig encompassing the XRCC5 (Ku80) DNA repair gene and complementation defective cells by YAC protoplast fusion. Genomics 30: 320-328, 1995.
2. Chen, D. J., Marrone, B. L., Nguyen, T., Stackhouse, M., Zhao, Y., Siciliano, M. J. Regional assignment of a human DNA repair gene (XRCC5) to 2q35 by x-ray hybrid mapping. Genomics 21: 423-427, 1994.
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