Adriamycin-induced DNA adducts inhibit the DNA interactions of transcription factors and RNA polymerase.
Adriamycin is known to specifically induce DNA interstrand cross-links at 5'-GC sequences. Because 5'-GC sequences are a predominant feature of 5'-untranslated regions (transcription factor-binding sites, promoter, and enhancer regions), it is likely that adriamycin adducts at GC sites would affect the binding of DNA-interacting proteins. Two model systems were chosen for the analysis: the octamer-binding proteins Oct-1, N-Oct-3 and N-Oct-5, which bind to ATGCAAAT and TAATGARAT recognition sites, and Escherichia coli RNA polymerase binding to the lac UV5 promoter. Electrophoretic mobility shift studies showed that adriamycin adducts at GC sites inhibited the binding of octamer proteins to their consensus motifs at drug levels as low as 1 micoM, but no effect was observed with a control sequence lacking a GC site. Adriamycin adducts at GC sites also inhibited the binding of RNA polymerase to the lac UV5 promoter. Adriamycin may therefore function by down-regulating the expression of specific genes by means of inactivation of short but critical motifs containing one or more GC sites.
Cutts
S M
SM
School of Biochemistry, La Trobe University, Bundoora, Victoria 3083, Australia.
Parsons
P G
PG
Sturm
R A
RA
Phillips
D R
DR
D000903:Antibiotics, Antineoplastic / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D004247:DNA / Q000187:drug effects / Q000378:metabolism*; D018736:DNA Adducts / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000187:drug effects / Q000378:metabolism*; D004317:Doxorubicin / Q000378:metabolism* / Q000494:pharmacology*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D018398:Homeodomain Proteins / Q000378:metabolism; D051863:Host Cell Factor C1; D007700:Kinetics; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D050814:Octamer Transcription Factor-3; D010957:Plasmids; D011401:Promoter Regions, Genetic; D013379:Substrate Specificity; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism*
D000903:Antibiotics, Antineoplastic; D018736:DNA Adducts; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; D050814:Octamer Transcription Factor-3; D014157:Transcription Factors; D004317:Doxorubicin; D004247:DNA; D012321:DNA-Directed RNA Polymerases