Establishment of a novel immortalized cell line from ataxia telangiectasia fibroblasts and its use for the chromosomal assignment of radiosensitivity gene.

An immortalized cell line was established from a female ataxia telangiectasia (AT) patient by the transfection of primary skin fibroblasts with origin-defective SV40 DNA. The cell line was characterized by a hypodiploid chromosome constitution and radiation hypersensitivity. The established cell line was used as a recipient for microcell-mediated chromosome transfer. Among seven G418-resistant clones obtained by the fusion with microcells from mouse A9 cells carrying a pSV2neo-tagged normal human chromosome 11, three clones showed restoration of radiation resistance with concomitant gain of an extra intact chromosome 11, while the others contained no recognizable or deleted chromosome 11. The association of the presence of 11q14----qter region with the radioresistance suggests the presence of AT gene in this chromosomal region.