title: Effect of heat treatment on chromosomal aberrations induced by the alkylating agent trenimon or the restriction endonuclease Alu I in Chinese hamster ovary (CHO) cells.
abstract: Heat treatment of CHO cells in the G1-phase of the cell cycle leads to chromatid-type aberrations in first posttreatment metaphases. Posttreatment of heat-treated cells with the alkylating agent trenimon leads to a synergistic effect on the production of chromatid-type exchanges. These results indicate that heat induces lesions which like the lesions produced by trenimon give rise to chromatid-type aberrations during the first posttreatment S-phase, and that these lesions can interact with each other to produce chromatid-type exchanges. Treatment of CHO cells in the G1-phase of the cell cycle with the restriction endonuclease Alu I induces chromosomal aberrations. Pretreatment of cells with heat leads to a reduction of Alu I induced chromosome-type aberrations. When cells are allowed to recover after heat treatment for 22 h, the aberration frequencies produced by Alu I are the same as in cells not treated with heat. These findings can be explained by assuming that heat-induced accumulation of accessory proteins in the chromatin protects the DNA from being cut by Alu I, and that the cells recovered from the heat-induced protein accumulation after 22 h.
mesh_terms: D000818:Animals; D002460:Cell Line; D002869:Chromosome Aberrations; D006224:Cricetinae; D004262:DNA Restriction Enzymes / Q000008:administration & dosage*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific; D006358:Hot Temperature; D014228:Triaziquone / Q000008:administration & dosage*
chemical_list: D004268:DNA-Binding Proteins; D004262:DNA Restriction Enzymes; C024669:endodeoxyribonuclease AluI; D015252:Deoxyribonucleases, Type II Site-Specific; D014228:Triaziquone