DNA damage by nitrogen mustard in a gene containing multiple Sp1-binding sites.
The human cytochrome c(1) gene TATA-less promoter contains 10 Sp1-binding elements that regulate the activation of transcription of this gene. Quantitative PCR was used to show that nitrogen mustard induces DNA lesions within this Sp1-binding region following exposure of HeLa cells to clinical levels of the drug. Alkylation of the cytochrome c(1) gene in HeLa cells increased with reaction time up to 4 h following exposure to nitrogen mustard, with 50% of the lesions (approximately 0.8/kb) forming within 1 h. An Sp1 competition assay showed that nitrogen mustard inhibited the binding of Sp1 to the promoter region of the cytochrome c(1) gene in HeLa cells. These results show that nitrogen mustard-induced damage to Sp1-binding sites may contribute to the toxicity of this compound by interfering with the activation of specific genes.
Chen
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Department of Biochemistry, La Trobe University, Bundoora, Victoria, 3083, Australia.
Cullinane
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Gray
P J
PJ
Phillips
D R
DR
D000477:Alkylating Agents / Q000633:toxicity*; D000478:Alkylation / Q000187:drug effects; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D003575:Cytochromes c1 / Q000235:genetics*; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells; D006801:Humans; D008466:Mechlorethamine / Q000633:toxicity*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
D000477:Alkylating Agents; D004273:DNA, Neoplasm; D016329:Sp1 Transcription Factor; D008466:Mechlorethamine; D003575:Cytochromes c1; D013762:Tetrahydrofolate Dehydrogenase