title: Benzpyrene groups bind preferentially to the DNA of active chromatin in human lung cells.
abstract: The cells of the bronchial epithelium of man are targets for benzo(a)pyrene carcinogenesis. When cultures of these cells, and of non-target fibroblasts, are exposed to [3H]-benzo(a)pyrene, we find that the epithelial cells metabolise and bind to DNA far greater amounts of benzpyrene than do fibroblasts. By analysis of nuclei of benzpyrene-treated cells for sensitivity to limited digestion with pancreatic DNase I, we have shown that benzpyrene groups bind initially to the DNA of expressed (DNase I sensitive) regions of chromatin in both cell types. Covalent binding of benzpyrene groups to non-expressed (DNase I resistant) regions follows rapidly in the target epithelial cells. These maintain high levels of carcinogen adducts in their DNA. In fibroblasts, benzpyrene group binding to non-expressed DNA occurs more slowly and active removal of adducts from the DNA is evident.
mesh_terms: D001564:Benzo(a)pyrene; D001580:Benzopyrenes / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D003850:Deoxyribonuclease I; D003851:Deoxyribonucleases; D004720:Endonucleases; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D014158:Transcription, Genetic
chemical_list: D001580:Benzopyrenes; D002843:Chromatin; D001564:Benzo(a)pyrene; D004247:DNA; D003851:Deoxyribonucleases; D004720:Endonucleases; D003850:Deoxyribonuclease I