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Updated: Jul 4, 2026

Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
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Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists

Published on: November 15, 2013

The nuclear receptor Rev-erbalpha is a liver X receptor (LXR) target gene driving a negative feedback loop on select

Coralie Fontaine1, Elena Rigamonti, Benoit Pourcet

  • 1Institut National de la Santé et de la Recherche Médicale, Unité 545, Institut Pasteur de Lille, 1, rue du Professeur Calmette, Boite Postale 245, Lille 59019, France.

Molecular Endocrinology (Baltimore, Md.)
|May 31, 2008
PubMed

Insights

Rev-erbalpha, a nuclear receptor, acts as a negative regulator in macrophages. It inhibits liver X receptor (LXR)-induced toll-like receptor 4 (TLR-4) expression, establishing a feedback loop.

Area of Science:

  • Molecular Biology
  • Immunology
  • Endocrinology

Background:

  • Nuclear receptors like Rev-erbalpha regulate transcription, often interacting with other nuclear receptors.
  • Rev-erbalpha acts as a transcriptional repressor, binding to response elements shared with receptors such as peroxisome proliferator-activated receptors and RORalpha.
  • Liver X receptors (LXRs) are crucial regulators of cholesterol homeostasis, inflammation, and immune responses in macrophages.

Purpose of the Study:

  • To investigate the role of Rev-erbalpha in human macrophages.
  • To determine if Rev-erbalpha expression is regulated by LXR agonists.
  • To elucidate the effect of Rev-erbalpha on LXR-mediated gene expression, specifically toll-like receptor 4 (TLR-4) and cholesterol homeostasis.

Main Methods:

  • Expression analysis of Rev-erbalpha in primary human macrophages.
  • Chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assays (EMSA) to study protein-DNA interactions.
  • Transient transfection experiments to assess promoter activity.
  • Short interfering RNA (siRNA) for Rev-erbalpha gene silencing.

Main Results:

  • Rev-erbalpha is expressed in human macrophages and its expression is induced by LXR ligands.
  • LXRalpha directly binds to the Rev-erbalpha promoter, inducing its transcription.
  • Rev-erbalpha overexpression represses LXR-induced TLR-4 expression, while Rev-erbalpha silencing enhances it.
  • Rev-erbalpha binds to the TLR-4 promoter, repressing its activity, but does not affect cholesterol homeostasis genes.

Conclusions:

  • Rev-erbalpha is identified as a novel LXR target gene in macrophages.
  • Rev-erbalpha establishes a negative transcriptional feedback loop by inhibiting LXR-induced TLR-4 expression.
  • Rev-erbalpha's regulatory role in this feedback loop does not extend to LXR-regulated cholesterol homeostasis genes.

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