Retinoid receptors promote primary neurogenesis in Xenopus

Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 515-523 ◽  
Author(s):  
C.R. Sharpe ◽  
K. Goldstone
Keyword(s):  
Retinoic Acid ◽  
Nuclear Hormone Receptor ◽  
Retinoic Acid Receptors ◽  
Primary Neurons ◽  
Retinoid X Receptors ◽  
Over Expression ◽  
Retinoid Receptors ◽  
X Receptors ◽  
Synthetic Mrna ◽  
Primary Neurogenesis

Retinoid receptors, which are members of the nuclear hormone receptor superfamily, act as ligand-dependent transcription factors. They mediate the effects of retinoic acid primarily as heterodimers of retinoic acid receptors (RARs) and retinoid X receptors (RXRs). To analyse their function, xRXR beta synthetic mRNA was injected into Xenopus embryos in combination with normal and mutated xRAR alpha transcripts. Two informative phenotypes are reported here. Firstly, over-expression of xRXR beta with xRAR alpha results in the formation of ectopic primary neurons. Secondly, blocking retinoid signalling with a mutated xRAR alpha results in a lack of primary neurons. These two phenotypes, from contra-acting manipulations, indicate a role for retinoid signalling during neurogenesis.

scholarly journals Multiple retinoid-responsive receptors in a single cell: families of retinoid "X" receptors and retinoic acid receptors in the Xenopus egg.

1992 ◽  
Vol 89 (6) ◽  
pp. 2321-2325 ◽  
Author(s):  
B. Blumberg ◽  
D. J. Mangelsdorf ◽  
J. A. Dyck ◽  
D. A. Bittner ◽  
R. M. Evans ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Single Cell ◽  
Retinoic Acid Receptors ◽  
Retinoid X Receptors ◽  
Xenopus Egg ◽  
X Receptors

Retinoic acid receptors and retinoid X receptors in the mature retina: Subtype determination and cellular distribution

1999 ◽  
Vol 19 (4) ◽  
pp. 338-347 ◽  
Author(s):  
Jacques J.M. Janssen ◽  
Eleonoor D. Kuhlmann ◽  
Anke H.M. van Vugt ◽  
Huub J. Winkens ◽  
Bert P.M. Janssen ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Retinoic Acid Receptors ◽  
Cellular Distribution ◽  
Retinoid X Receptors ◽  
X Receptors

Terminal differentiation in keratinocytes involves positive as well as negative regulation by retinoic acid receptors and retinoid X receptors at retinoid response elements

1992 ◽  
Vol 12 (11) ◽  
pp. 4862-4871
Author(s):  
B J Aneskievich ◽  
E Fuchs
Keyword(s):  
Retinoic Acid ◽  
Terminal Differentiation ◽  
Cell Types ◽  
Epidermal Differentiation ◽  
Retinoic Acid Receptors ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Retinoid X Receptors ◽  
Response Elements ◽  
X Receptors

Terminal differentiation of epidermal keratinocytes is inhibited by 1 microM retinoic acid, a concentration which induces differentiation in a number of cell types, including F9 teratocarcinoma cells. The molecular basis for these opposing retinoid responses is unknown, although retinoic acid receptors (RARs) and retinoid X receptors (RXRs) have been detected in both cell types. When F9 cells are stably transfected with a truncated RAR alpha lacking the E/F domain necessary for ligand binding and RAR/RXR dimerization, action at retinoid response elements is suppressed and cells produce a retinoic acid-resistant phenotype; i.e., they are blocked in differentiation (A. S. Espeseth, S. P. Murphy, and E. Linney, Genes Dev. 3:1647-1656, 1989). If retinoid receptors influence epidermal differentiation only in a negative fashion, then suppression of transactivation at retinoid response elements would be expected to enhance, rather than block, keratinocyte differentiation. In this study, we show that surprisingly, even though constitutive expression of an analogous truncated RAR gamma in keratinocytes specifically suppressed transactivation at retinoid response elements, keratinocytes were blocked, rather than enhanced, in their ability to undergo morphological and biochemical features of differentiation. These findings demonstrate a direct and hitherto unrecognized role for RARs and RXRs in positively as well as negatively regulating epidermal differentiation. Additionally, our studies extend those of Espeseth et al. (Genes Dev. 3:1647-1656, 1989), indicating a novel RAR function independent of the E/F domain.

scholarly journals Different agonist- and antagonist-induced conformational changes in retinoic acid receptors analyzed by protease mapping.

1994 ◽  
Vol 14 (1) ◽  
pp. 287-298 ◽  
Author(s):  
S Keidel ◽  
P LeMotte ◽  
C Apfel
Keyword(s):  
Retinoic Acid ◽  
Conformational Changes ◽  
Vitamin D3 ◽  
Target Genes ◽  
Retinoic Acid Receptors ◽  
Proteolytic Fragment ◽  
Retinoid Receptors ◽  
Agonist And Antagonist ◽  
X Receptors ◽  
Differentiation And Proliferation

The pleiotropic effects of retinoic acid on cell differentiation and proliferation are mediated by two subfamilies of nuclear receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). Recently the synthetic retinoid Ro 41-5253 was identified as a selective RAR alpha antagonist. As demonstrated by gel retardation assays, Ro 41-5253 and two related new RAR alpha antagonists do not influence RAR alpha/RXR alpha heterodimerization and DNA binding. In a limited trypsin digestion assay, complexation of RAR alpha with retinoic acid or several other agonistic retinoids altered the degradation of the receptor such that a 30-kDa proteolytic fragment became resistant to proteolysis. This suggests a ligand-induced conformational change, which may be necessary for the interaction of the DNA-bound RAR alpha/RXR alpha heterodimer with other transcription factors. Our results demonstrate that antagonists compete with agonists for binding to RAR alpha and may induce a different structural alteration, suggested by the tryptic resistance of a shorter 25-kDa protein fragment in the digestion assay. This RAR alpha conformation seems to allow RAR alpha/RXR alpha binding to DNA but not the subsequent transactivation of target genes. Protease mapping with C-terminally truncated receptors revealed that the proposed conformational changes mainly occur in the DE regions of RAR alpha. Complexation of RAR beta, RAR gamma, and RXR alpha, as well as the vitamin D3 receptor, with their natural ligands resulted in a similar resistance of fragments to proteolytic digestion. This could mean that ligand-induced conformational changes are a general feature in the hormonal activation of vitamin D3 and retinoid receptors.

Lycopene-derived bioactive retinoic acid receptors/retinoid-X receptors-activating metabolites may be relevant for lycopene's anti-cancer potential

2013 ◽  
Vol 57 (5) ◽  
pp. 739-747 ◽  
Author(s):  
Gamze Aydemir ◽  
Yasamin Kasiri ◽  
Eszter Birta ◽  
Gabriella Béke ◽  
Ada L. Garcia ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Retinoic Acid Receptors ◽  
Retinoid X Receptors ◽  
Anti Cancer ◽  
X Receptors
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