Analysis of XRCC4 in human somatic cells by gene targeting technique

Abstract

Nonhomologous DNA end joining (NHEJ) is the major pathway for repairing DNA double-strand breaks (DSBs). XRCC4 is NHEJ protein employed in DNA DSBs repair and in V(D)J recombination. To address the role of XRCC4 in human cells, we used gene targeting in human somatic tissue culture, human HCT116 colon cancer cells, to functionally inactivate the XRCC4 locus. Human XRCC4 heterozygous cell lines displayed haploinsufficient with reduction in cell proliferation but not hypersensitivity to ionizing radiation. A second round of gene targeting generated homozygously null XRCC4 cell lines. These cells showed a growth defect and hypersensitivity to ionizing radiation. [J Radiat Res 44:408 (2003)]