title: Transcriptionally active and inactive genes are similarly modified by chemical carcinogens or X-ray in normal human fibroblasts.
abstract: Chemical carcinogens and ionizing radiation induce DNA modifications and strand breaks in cells. This damage is reported to be affected by chromatin proteins or chromatin of a higher structure order. To compare the sensitivity of transcriptionally active and inactive genes on chromatin toward DNA-damaging agents, we treated normal human fibroblasts (WI-38) cells in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), X-ray, 4-hydroxyaminoquinoline 1-oxide or N-acetoxy-2-acetylaminofluorene, and high molecular weight DNA was isolated. After digestion with EcoRI to completion, the DNA was electrophoresed on an alkaline agarose gel, blotted on a nitrocellulose filter and hybridized with a transcriptionally active gene probe (human type I(alpha 2) procollagen gene) or an inactive gene probe (human beta-globin gene). The results show that both genes are similarly modified by these agents. Repair of DNA damage caused by MNNG also occurred similarly in collagen and beta-globin genes after removal of MNNG.
mesh_terms: D002273:Carcinogens / Q000633:toxicity*; D002460:Cell Line; D003094:Collagen / Q000235:genetics; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts; D005796:Genes / Q000187:drug effects / Q000528:radiation effects*; D005914:Globins / Q000235:genetics; D006801:Humans; D008168:Lung / Q000196:embryology; D008769:Methylnitronitrosoguanidine / Q000633:toxicity; D009693:Nucleic Acid Hybridization; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects*
chemical_list: D002273:Carcinogens; D008769:Methylnitronitrosoguanidine; D005914:Globins; D003094:Collagen