Article

The Orphan Nuclear Receptor Rev-erbα Recruits the N-CoR/Histone Deacetylase 3 Corepressor to Regulate the Circadian Bmal1 Gene

William Penn University, Filadelfia, Pennsylvania, United States
Molecular Endocrinology (Impact Factor: 4.02). 07/2005; 19(6):1452-9. DOI: 10.1210/me.2005-0057
Source: PubMed

ABSTRACT

Transcriptional regulation plays a fundamental role in controlling circadian oscillation of clock gene expression. The orphan nuclear receptor Rev-erbalpha has recently been implicated as a major regulator of the circadian clock. Expression of Bmal1, the master regulator of circadian rhythm in mammals, is negatively correlated with Rev-erbalpha mRNA level, but the molecular mechanism underlying this regulation is largely unknown. Here we show that Rev-erbalpha dramatically represses the basal activity of the mouse Bmal1 gene promoter via two monomeric binding sites, both of which are required for repression and are conserved between mouse and human. Rev-erbalpha directly binds to the mouse Bmal1 promoter and recruits the endogenous nuclear receptor corepressor (N-CoR)/histone deacetylase 3 (HDAC3) complex, in association with a decrease in histone acetylation. The endogenous N-CoR/HDAC3 complex is also associated with the endogenous Bmal1 promoter in human HepG2 liver cells, where a reduction in cellular HDAC3 level markedly increases the expression of Bmal1 mRNA. These data demonstrate a new function for the N-CoR/HDAC3 complex in regulating the expression of genes involved in circadian rhythm by functioning as corepressor for Rev-erbalpha.

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Available from: Mitchell A Lazar, Jul 08, 2015
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    • "REV-ERBa usually functions as a transcriptional repressor for the lack of activation function (AF-2) domain present at the C-terminal of the ligand-binding domain (Yin and Lazar 2005;Phelan et al. 2010;Crumbley and Burris 2011). REV-ERBa recruits the endogenous nuclear receptor corepressor (N-CoR)/histone deacetylase3 complex to repress its target gene transcription, thereby regulating a diverse array of cellular processes (Yin and Lazar 2005;Yin et al. 2006). REV-ERBa was originally regarded as an orphan nuclear receptor (Miyajima et al. 1989), and thereafter heme was identified as its natural ligand (Yin et al. 2007;Meng et al. 2008;Grant et al. 2010;Kojetin et al. 2011). "
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    ABSTRACT: Cellular oscillators in the uterus play critical roles in the gestation processes of mammals through entraining of the clock proteins to numerous downstream genes, including growth/differentiation factor (Gdf)10 and Gdf15. The expression of Gdf10 and Gdf15 is significantly increased in the uterus during decidualization, but the mechanism underlying the regulation of Gdf gene expression in the uterus is poorly understood. Here, we focused on the function of the cellular oscillators in the expression of Gdf family by using uterine endometrial stromal cells (UESCs) isolated from pregnant Per2-dLuc transgenic rats. A significant decline of Per2-dLuc bioluminescence activity was induced in in vitro decidualized UESCs, and concomitantly the expression of canonical clock genes was downregulated. Conversely, the expression of Gdf10 and Gdf15 of the Gdf was upregulated. In UESCs transfected with Bmal1-specific siRNA, in which Rev-erbα expression was downregulated, Gdf10 and Gdf15 were upregulated. However, Gdf5, Gdf7, and Gdf11 were not significantly affected by Bmal1 silencing. The expression of Gdf10 and Gdf15 was enhanced after treatment with a REV-ERBα antagonist in the presence or absence of progesterone. Chromatin immunoprecipitation-PCR analysis revealed the inhibitory effect of REV-ERBα on the expression of Gdf10 and Gdf15 in UESCs by recognizing their gene promoters. Collectively, our findings indicate that the attenuation of REV-ERBα leads to an upregulation of Gdf10 and Gdf15 in decidual cells, in which cellular oscillators are impaired. Our results provide novel evidence regarding the functions of cellular oscillators regulating the expression of downstream genes during the differentiation of UESCs.
    Full-text · Article · Feb 2016
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    • "The N-CoR/HDAC3 complex has been shown previously to be recruited by REV-ERBa to repress RRE-driven gene transcription (Yin and Lazar, 2005). However, knockout of Hdac3 does not completely phenocopy the Rev-Erba mutant, suggesting that Rev-Erba might have other functions in addition to recruiting HDAC3. "
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    ABSTRACT: In the core mammalian circadian negative feedback loop, the BMAL1-CLOCK complex activates the transcription of the genes Period (Per) and Cryptochrome (Cry). To close the negative feedback loop, the PER-CRY complex interacts with the BMAL1-CLOCK complex to repress its activity. These two processes are separated temporally to ensure clock function. Here, we show that histone deacetylase 3 (HDAC3) is a critical component of the circadian negative feedback loop by regulating both the activation and repression processes in a deacetylase activity-independent manner. Genetic depletion of Hdac3 results in low-amplitude circadian rhythms and dampened E-box-driven transcription. In subjective morning, HDAC3 is required for the efficient transcriptional activation process by regulating BMAL1 stability. In subjective night, however, HDAC3 blocks FBXL3-mediated CRY1 degradation and strongly promotes BMAL1 and CRY1 association. Therefore, these two opposing but temporally separated roles of HDAC3 in the negative feedback loop provide a mechanism for robust circadian gene expression.
    Full-text · Article · Jan 2016 · Cell Reports
    • "It is widely accepted that the nuclear receptor REV- ERBa is an important clock component of integrating circadian clock and many physiological processes such as adipogenesis, immunity, and lipid metabolism (Feng et al., 2011; Fontaine et al., 2003; Gibbs et al., 2012; Laitinen et al., 2005; Preitner et al., 2002; Triqueneaux et al., 2004; Yin & Lazar, 2005). REV-ERBa usually functions as a transcriptional repressor for the lack of activation function (AF-2) domain present at the Cterminal of the ligand-binding domain (Crumbley & Burris, 2011; Phelan et al., 2010; Yin & Lazar, 2005). "
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    ABSTRACT: The nuclear receptor REV-ERBα links circadian rhythms and numerous physiological processes, but its physiological role in ovaries remains largely unknown. The aim of this study was to determine the potential role of REV-ERBα in the regulation of the transcription of its putative target genes in granulosa cells (GCs) prepared from Per2-destablized luciferase (dLuc) reporter gene transgenic rats. Alas1, Ppargc1a, and Il6 were chosen as representatives for genes analysis. A real-time monitoring system of Per2 promoter activity was performed to detect Per2-dLuc circadian oscillations. Two agonists (GSK4112, heme) and an antagonist (SR8278) of REV-ERBα as well as Rev-erbα siRNA knockdown were used to identify its target genes. Clear Per2-dLuc circadian oscillations were generated in matured GCs after synchronization with GSK4112 or SR8278. GSK4112 treatment lengthened and SR8278 treatment shortened the period of circadian oscillations in matured GCs stimulated with or without luteinizing hormone (LH). GSK4112 showed an inhibitory effect on the amplitude of circadian oscillations and caused an arrhythmic expression of canonical clock genes. SR8278 also had a subtle effect on their daily expression profiles, but the treatment resulted only in the arrhythmic expression of Rev-erbα. These findings indicate the functional biological activity of REV-ERBα in response to its ligands. Its natural ligand heme further elongated the period of circadian oscillations and alleviated their amplitudes in GCs cultured with LH. Heme treatment also repressed the expressions of clock genes, Alas1, Il6, and Ppargc1a. Rev-erbα knockdown up-regulated these transcript levels. Collectively, these data extend the recent finding to rat GCs and demonstrate that REV-ERBα represses the expressions of Alas1, Ppargc1a, and Il6, providing novel insights into the physiological significance of REV-ERBα in ovarian circadian oscillators.
    No preview · Article · Jun 2015 · Chronobiology International
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