Differential sensitivity of transcription factors to mustard-damaged DNA.
Nitrogen mustard (bis(2-chloroethyl) methylamine, HN2) inhibited the binding of upstream factors Sp1 and AP2 to their consensus sequences. At concentrations where 50% of the consensus sequence DNA contained at least one lesion, HN2 inhibited formation of the Sp1 complex by 37% (40 microM HN2) and the AP2 complex by 40% (50 microM HN2). The binding of the TATA binding protein (TBP) to the TATA element was also inhibited by HN2, whereas sulphur mustard and the monofunctional sulphur mustard 2-chloroethyl ethyl sulphide (CEES) resulted in a disproportional extent of inhibition with respect to the level of alkylation. The level of alkylation of the TBP oligonucleotide varied significantly at 100 microM drug, with 80, 42 and 15% of HN2, sulphur mustard and CEES, respectively. However, this level of alkylation inhibited formation of the TBP-DNA complex by 70, 70 and 45%, respectively. This differential sensitivity of transcription factors to mustard-induced DNA damage therefore appears to reside dominantly in the stereochemical differences between the specific mustard lesions.
Chen
X M
XM
Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia.
Gray
P J
PJ
Cullinane
C
C
Phillips
D R
DR
D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D018736:DNA Adducts / Q000633:toxicity*; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008466:Mechlorethamine / Q000633:toxicity*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism; D016385:TATA Box; D035181:TATA-Box Binding Protein; D050656:Transcription Factor AP-2; D035581:Transcription Factor TFIIB; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D014158:Transcription, Genetic
D018736:DNA Adducts; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D016329:Sp1 Transcription Factor; D035181:TATA-Box Binding Protein; D050656:Transcription Factor AP-2; D035581:Transcription Factor TFIIB; D014157:Transcription Factors; D008466:Mechlorethamine; D012321:DNA-Directed RNA Polymerases