Regional localization of the XRCC4 human radiation repair gene.

To map the XRCC4 human DNA repair gene subchromosomally, a gamma-ray-resistant human:XR-1 hamster hybrid cell containing fragments of human chromosome 5 and the pSV2neo plasmid was lethally irradiated and fused with the gamma-ray-sensitive XR-1 mutant cell. After selection for G418 resistance, 2 of a total of 76 hybrids retained wildtype gamma-ray resistance. FISH analysis of normal human lymphocytes using DNA from the two resistant hybrids as probes produced a common region of hybridization at 5q13-q14, suggesting that the XRCC4 gene is in this region of chromosome 5. The gene was physically localized between D5S427 and D5S401 microsatellite markers and the cytological assignment confirmed using hamster:human hybrids containing known deletions in human chromosome 5.