کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1991898 1541035 2011 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Intercalation of XR5944 with the estrogen response element is modulated by the tri-nucleotide spacer sequence between half-sites
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Intercalation of XR5944 with the estrogen response element is modulated by the tri-nucleotide spacer sequence between half-sites
چکیده انگلیسی

DNA-intercalating molecules can impair DNA replication, DNA repair, and gene transcription. We previously demonstrated that XR5944, a DNA bis-intercalator, specifically blocks binding of estrogen receptor-α (ERα) to the consensus estrogen response element (ERE). The consensus ERE sequence is AGGTCAnnnTGACCT, where nnn is known as the tri-nucleotide spacer. Recent work has shown that the tri-nucleotide spacer can modulate ERα–ERE binding affinity and ligand-mediated transcriptional responses. To further understand the mechanism by which XR5944 inhibits ERα–ERE binding, we tested its ability to interact with consensus EREs with variable tri-nucleotide spacer sequences and with natural but non-consensus ERE sequences using one dimensional nuclear magnetic resonance (1D 1H NMR) titration studies. We found that the tri-nucleotide spacer sequence significantly modulates the binding of XR5944 to EREs. Of the sequences that were tested, EREs with CGG and AGG spacers showed the best binding specificity with XR5944, while those spaced with TTT demonstrated the least specific binding. The binding stoichiometry of XR5944 with EREs was 2:1, which can explain why the spacer influences the drug–DNA interaction; each XR5944 spans four nucleotides (including portions of the spacer) when intercalating with DNA. To validate our NMR results, we conducted functional studies using reporter constructs containing consensus EREs with tri-nucleotide spacers CGG, CTG, and TTT. Results of reporter assays in MCF-7 cells indicated that XR5944 was significantly more potent in inhibiting the activity of CGG- than TTT-spaced EREs, consistent with our NMR results. Taken together, these findings predict that the anti-estrogenic effects of XR5944 will depend not only on ERE half-site composition but also on the tri-nucleotide spacer sequence of EREs located in the promoters of estrogen-responsive genes.

Research highlights
► Tested binding of XR5944 with EREs containing variable tri-nucleotide spacer sequences.
► The spacer sequence significantly modulates the binding of XR5944 to EREs.
► The binding stoichiometry of XR5944 with EREs was 2:1.
► XR5944 inhibits ERE transactivation according to its relative binding specificity to ERE.
► The tri-nucleotide spacer sequence is involved in the interaction of XR5944 with EREs.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Steroid Biochemistry and Molecular Biology - Volume 124, Issues 3–5, April 2011, Pages 121–127
نویسندگان
, , , , , ,