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Estrogen receptor alpha (ERα) is a ligand-responsive transcription factor critical for sex determination and development. Recent reports challenge the canonical view of ERα function by suggesting an activity beyond binding dsDNA at estrogen-responsive promotor elements: association with RNAs in vivo. Whether these interactions are direct or indirect remains unknown, which limits the ability to understand the extent, specificity, and biological role of ERα-RNA binding. Here we demonstrate that an extended DNA-binding domain of ERα directly binds a wide range of RNAs in vitro with structural specificity. ERα binds RNAs that adopt a range of hairpin-derived structures independent of sequence, while interacting poorly with single- and double-stranded RNA. RNA affinities are only 4-fold weaker than consensus dsDNA and significantly tighter than nonconsensus dsDNA sequences. Moreover, RNA binding is competitive with DNA binding. Together, these data show that ERα utilizes an extended DNA-binding domain to achieve a high-affinity/low-specificity mode for interacting with RNA.
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Activation of Caged Functional RNAs by An Oxidative Transformation
Abstract RNA exhibits remarkable capacity as a functional polymer, with broader catalytic and ligand‐binding capability than previously thought. Despite this, the low side chain diversity present in nucleic acids (two purines and two pyrimidines) relative to proteins (20+ side chains of varied charge, polarity, and chemical functionality) limits the capacity of functional RNAs to act as environmentally responsive polymers, as is possible for peptide‐based receptors and catalysts. Here we show that incorporation of the modified nucleobase 2‐thiouridine (2sU) into functional (aptamer and ribozyme) RNAs produces functionally inactivated polymers that can be activated by oxidative treatment. 2‐thiouridine lacksthe 2‐position oxygen found in uridine, altering its hydrogen bonding pattern. This limits critical interactions (e. g., G−U wobble pairs) that allow for proper folding. Oxidative desulfurization of the incorporated 2‐thiouridine moieties to uridine relieves this inability to fold properly, enabling recovery of function. This demonstration of expanded roles for RNA as environmentally responsive functional polymers challenges the notion that they are not known to be redox‐sensitive. Harnessing redox switchability in RNA could regulate cellular activities such as translation, or allow switching RNA between a “template” and a “catalytic” state in “RNA World” scenarios or in synthetic biology.
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- Award ID(s):
- 2338121
- PAR ID:
- 10583358
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemBioChem
- Volume:
- 26
- Issue:
- 8
- ISSN:
- 1439-4227
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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