The orphan receptor Rev-ErbAα activates transcription via a novel response element

Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104.
Molecular and Cellular Biology (Impact Factor: 4.78). 06/1993; 13(5):3113-21. DOI: 10.1128/MCB.13.5.3113
Source: PubMed

ABSTRACT Rev-ErbA alpha (Rev-Erb) is a nuclear hormone receptor-related protein encoded on the opposite strand of the alpha-thyroid hormone receptor (TR) gene. This unusual genomic arrangement may have a regulatory role, but the conservation of human and rodent Rev-Erb amino acid sequences suggests that the protein itself has an important function, potentially as a sequence-specific transcriptional regulator. However, despite its relationship to the TR, Rev-Erb bound poorly to TR binding sites. To determine its DNA-binding specificity in an unbiased manner, Rev-Erb was synthesized in Escherichia coli, purified, and used to select specific binding-sites from libraries of random double-stranded DNA sequences. We found that Rev-Erb binds to a unique site consisting of a specific 5-bp A/T-rich sequence adjacent to a TR half-site. Rev-Erb contacts this entire asymmetric 11-bp sequence, which is the longest nonrepetitive element specifically recognized by a member of the thyroid/steroid hormone receptor superfamily, and mutations in either the A/T-rich or TR half-site regions abolished specific binding. The binding specificity of wild-type Rev-Erb was nearly identical to that of C- and N-terminally truncated forms. This binding was not enhanced by retinoid X receptor, TR, or other nuclear proteins, none of which formed heterodimers with Rev-Erb. Rev-Erb also appeared to bind to the selected site as a monomer. Furthermore, Rev-Erb activates transcription through this binding site even in the absence of exogenous ligand. Thus, Rev-Erb is a transcriptional activator whose properties differ dramatically from those of classical nuclear hormone receptors, including the TR encoded on the opposite strand of the same genomic locus.

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Available from: Mitchell A Lazar, Sep 26, 2015
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    • "The core nucleotides of response elements and the flanking nucleotides are shown in black and gray letters, respectively. The ROR response element (RORE) (Giguere et al. 1994) and REVERB response element (RRE) (Harding & Lazar 1993) are also shown in the figure. The underline indicates the positions of mutations. "
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    ABSTRACT: DEC1 and DEC2, members of the basic helix-loop-helix superfamily, are involved in various biological phenomena including clock systems, cell differentiation and metabolism. In clock systems, Dec1 and Dec2 expression are up-regulated by the CLOCK:BMAL1 heterodimer via E-box (CACGTG), exhibiting a circadian rhythm in the suprachiasmatic nucleus (SCN), the central circadian pacemaker and other peripheral tissues. In this study, using assays of luciferase reporters, electrophoretic mobility shift and chromatin immunoprecipitation, we identified novel nuclear receptor response elements, ROR response elements (RORE), in Dec1 and Dec2 promoters. These ROREs responded to the transcriptional activator RORα, but not to the repressor REVERBα, although the Bmal1 promoter responded to both RORα and REVERBα. Therefore, RORα, but not REVERBα, is involved in the regulation of Dec1 and Dec2 expression without significantly affecting their rhythmicity. Since RORα, DEC1 and DEC2 reportedly suppressed adipogenic differentiation, we examined expression of Rorα, Dec1, Dec2 and other clock-controlled genes in differentiating 3T3-L1 adipocytes. The results suggested that RORα suppresses adipogenic differentiation at a later stage of differentiation by RORE-mediated stimulation of Dec1 and Dec2 expression.
    Genes to Cells 01/2012; 17(2):109-21. DOI:10.1111/j.1365-2443.2011.01574.x · 2.81 Impact Factor
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    • "Nr1d1 appears to have a diverse role in regulating gene networks in many tissue types and several biological processes. Additionally, activated Nr1d1 is able to function as a monomer or a dimer, and is capable of repressing or activating gene expression, suggesting that Nr1d1 has a diverse role in gene regulation [31]–[33]. Little is known about the role of Nr1d1 in the mammalian retina, however its expression has been studied in a variety of tissues including skeletal muscle, liver, adipose, and eye, with its highest expression in the eye [3], [29], [34]–[38]. Nr1d1 has been widely studied for its role in transcriptional regulation of processes such as circadian rhythm and metabolism, with heme functioning as an endogenous ligand [39]–[40]. "
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    ABSTRACT: The majority of diseases in the retina are caused by genetic mutations affecting the development and function of photoreceptor cells. The transcriptional networks directing these processes are regulated by genes such as nuclear hormone receptors. The nuclear hormone receptor gene Rev-erb alpha/Nr1d1 has been widely studied for its role in the circadian cycle and cell metabolism, however its role in the retina is unknown. In order to understand the role of Rev-erb alpha/Nr1d1 in the retina, we evaluated the effects of loss of Nr1d1 to the developing retina and its co-regulation with the photoreceptor-specific nuclear receptor gene Nr2e3 in the developing and mature retina. Knock-down of Nr1d1 expression in the developing retina results in pan-retinal spotting and reduced retinal function by electroretinogram. Our studies show that NR1D1 protein is co-expressed with NR2E3 in the outer neuroblastic layer of the developing mouse retina. In the adult retina, NR1D1 is expressed in the ganglion cell layer and is co-expressed with NR2E3 in the outer nuclear layer, within rods and cones. Several genes co-targeted by NR2E3 and NR1D1 were identified that include: Nr2c1, Recoverin, Rgr, Rarres2, Pde8a, and Nupr1. We examined the cyclic expression of Nr1d1 and Nr2e3 over a twenty-four hour period and observed that both nuclear receptors cycle in a similar manner. Taken together, these studies reveal a novel role for Nr1d1, in conjunction with its cofactor Nr2e3, in regulating transcriptional networks critical for photoreceptor development and function.
    PLoS ONE 03/2011; 6(3):e17494. DOI:10.1371/journal.pone.0017494 · 3.23 Impact Factor
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    • "In mammalian clocks, circadian transcriptional program is mediated through at least three clock-controlled DNA elements, morning-time (E box/E 0 box, or E/E 0 box: CACGT[G/T]) (Gekakis, 1998; Hogenesch et al., 1997; Ueda et al., 2005; Yoo et al., 2005), day-time (D box: TTA[T/C]GTAA) (Falvey et al., 1996; Ueda et al., 2005), and night-time elements (Rev-Erb/ROR-binding element, or RRE: [A/T]A[A/T]NT[A/G]GGTCA) (Harding and Lazar, 1993; Preitner et al., 2002; Ueda et al., 2002, 2005). The E/E 0 box-mediated transcriptional program has a critical role in the core autoregulatory loop of the mammalian circadian clock (Gekakis, 1998; Sato et al., 2006; Ueda et al., 2005). "
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