Defective repair of radiation-induced chromosomal damage in scid/scid mice.
The murine severe combined immunodeficiency (scid) mutation interferes with normal recombination of immunoglobulin and T-cell receptor genes. This immunologic defect results in a lack of fully differentiated B and T cells in scid/scid mice. Animals homozygous for the scid mutation also display increased sensitivity to the damaging effects of ionizing radiation. We report here our observations of high frequencies of radiation-induced chromatid interchanges and intrachanges in bone marrow cells and fibroblasts from scid/scid mice. The presence of these aberrant chromosome structures suggests that a delay in strand rejoining underlies the increased sensitivity of scid/scid mice to ionizing radiation. The scid mutation may provide important clues for understanding the relationship between mitotic recombination and DNA repair in higher eukaryotic cells.
Disney
J E
JE
Jackson Laboratory, Bar Harbor, ME 04609.
Barth
A L
AL
Shultz
L D
LD
D000818:Animals; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects*; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D051379:Mice; D016513:Mice, SCID / Q000235:genetics*; D009154:Mutation / Q000235:genetics