Transcriptional activation of thymidylate synthase by 17beta-estradiol in MCF-7 human breast cancer cells.
Thymidylate synthase (TS) catalyzes methylation of deoxyuridine phosphate to give deoxythymidine phosphate, and 17beta-estradiol (E2) induces TS gene expression in MCF-7 human breast cancer cells. Analysis of the TS gene promoter showed that E2-responsiveness required the -229 to -140 promoter region containing a G-rich sequence and CACCC box. Subsequent mutational analysis of this region indicated that only the G-rich motif (-150 to -142) was required for E2 action. Results of gel mobility shift and in vitro DNA footprinting assays showed that both estrogen receptor alpha (ERalpha) and Sp1 proteins were required for hormone-induced trans-activation that involved ERalpha/Sp1 binding to the G-rich site in which only Sp1 protein bound DNA. Both proteins also interacted in Drosophila cells in functional assays, confirming the transcriptional activation of TS-involved ERalpha/Sp1, and this adds to the increasing number of genes that are activated through this pathway in breast cancer cells.
Xie
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Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station 77843-4466, USA.
Duan
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Chen
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Samudio
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Safe
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D000818:Animals; D001483:Base Sequence / Q000235:genetics; D018983:DNA Footprinting; D015257:DNA-Cytosine Methylases / Q000378:metabolism; D004330:Drosophila / Q000166:cytology / Q000378:metabolism; D004789:Enzyme Activation; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000502:physiology; D016329:Sp1 Transcription Factor / Q000378:metabolism / Q000502:physiology; D013940:Thymidylate Synthase / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D047628:Estrogen Receptor alpha; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D016329:Sp1 Transcription Factor; D004958:Estradiol; C081573:DNA modification methylase SssI; D015257:DNA-Cytosine Methylases; D013940:Thymidylate Synthase