title: Southern analysis of genomic alterations in gamma-ray-induced aprt- hamster cell mutants.
abstract: The role of genomic alterations in mutagenesis induced by ionizing radiation has been the subject of considerable speculation. By Southern blotting analysis we show here that 9 of 55 (approximately 1/6) gamma-ray-induced mutants at the adenine phosphoribosyl transferase (aprt) locus of Chinese hamster ovary (CHO) cells have a detectable genomic rearrangement. These fall into two classes: intragenic deletions and chromosomal rearrangements. In contrast, no major genomic alterations were detected among 67 spontaneous mutants, although two restriction site loss events were observed. Three gamma-ray-induced mutants were found to be intragenic deletions; all may have identical break-points. The remaining six gamma-ray-induced mutants demonstrating a genomic alteration appear to be the result of chromosomal rearrangements, possibly translocation or inversion events. None of the remaining gamma-ray-induced mutants showed any observable alteration in blotting pattern indicating a substantial role for point mutation in gamma-ray-induced mutagenesis at the aprt locus.
mesh_terms: D000228:Adenine Phosphoribosyltransferase / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D005260:Female; D005796:Genes / Q000528:radiation effects*; D008970:Molecular Weight; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010053:Ovary; D010430:Pentosyltransferases / Q000235:genetics*
chemical_list: D004247:DNA; D010430:Pentosyltransferases; D000228:Adenine Phosphoribosyltransferase; D004262:DNA Restriction Enzymes