Ligand-bound RXR can mediate retinoid signal transduction during embryogenesis

Development ◽  
1997 ◽  
Vol 124 (1) ◽  
pp. 195-203 ◽  
Author(s):  
H.C. Lu ◽  
G. Eichele ◽  
C. Thaller
Keyword(s):  
Signal Transduction ◽  
Retinoic Acid ◽  
Experimental System ◽  
Limb Bud ◽  
Retinoic Acid Receptors ◽  
Vertebrate Development ◽  
High Affinity ◽  
X Receptors ◽  
Complex Expression

Retinoids regulate various aspects of vertebrate development through the action of two types of receptors, the retinoic acid receptors (RARs) and the retinoid-X-receptors (RXRs). Although RXRs bind 9-cis-retinoic acid (9cRA) with high affinity, in vitro experiments suggest that RXRs are for the most part not liganded, but serve as auxiliary factors forming heterodimers with liganded partner receptors such as RAR. Here we have used RXR- and RAR-specific ligands 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-napthyl)ethenyl]b enzoic acid (LG69) and (E)-4-[2-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthalenyl)-1-prope nyl]benzoic acid (TTNPB), and show that, in the context of an embryo, liganded RXR can mediate retinoid signal transduction. This conclusion emerges from examining the induction of several retinoid-responsive genes in the limb bud (Hoxb-6/-8, RARbeta) and in the developing central nervous system (Hoxb-1, otx-2). RARbeta and Hoxb-1 genes were most effectively activated by a combination of TTNPB and LG69, suggesting that the activation of these genes benefits from the presence of ligand-bound RAR and ligand-bound RXR. Hoxb-6/-8 genes were most efficiently induced by LG69, suggesting that liganded RXR can activate these genes. The regulation of the expression of the otx-2 gene was complex; expression was repressed by TTNPB, but such repression was relieved when LG69 was provided together with TTNPB, suggesting that ligand-bound RXR can overcome repression of transcription exerted by liganded RAR. Based on these findings, we propose that in our experimental system in which ligands are provided exogenously, transcriptional regulation of several genes involves liganded RXR.

scholarly journals 9-cis-retinoic acid is a natural antagonist for the retinoic acid receptor response pathway

1993 ◽  
Vol 295 (2) ◽  
pp. 343-346 ◽  
Author(s):  
C Carlberg ◽  
J H Saurat ◽  
G Siegenthaler
Keyword(s):  
Retinoic Acid ◽  
Retinoic Acid Receptor ◽  
Retinoic Acid Receptors ◽  
Dependent Manner ◽  
Receptor Response ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
X Receptors ◽  
Dose Dependent

The pleiotropic activities of retinoids are mediated by two types of nuclear receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). All-trans-retinoic acid (RA) transcriptionally activates RARs, but not RXRs, whereas its natural stereoisomer, 9-cis-RA, is the ligand for RXRs. Here, we demonstrate that 9-cis-RA did not transcriptionally activate RARs, whereas in the presence of all-trans-RA the transactivation of RARs was inhibited in a dose-dependent manner by 9-cis-RA. RAR homodimer complexes were destabilized in vitro in the presence of 9-cis-RA. This suggests that 9-cis-RA may be a natural antagonist of all-trans-RA for binding to RAR complexes. The levels of 9-cis-RA may determine by which pathway the transcription of retinoid-responsive genes is modulated.

Oestrogen and progesterone do not regulate the expression of retinoic acid receptors and retinoid ‘X’ receptors in human endometrial stromal cells in vitro

1994 ◽  
Vol 9 (2) ◽  
pp. 229-234 ◽  
Author(s):  
M.Kumar Kumarendran ◽  
C.Jane Matthews ◽  
Mark D. Levasseur ◽  
Andrew Prentice ◽  
Eric J. Thomas ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Stromal Cells ◽  
Retinoic Acid Receptors ◽  
Endometrial Stromal Cells ◽  
Retinoid X Receptors ◽  
X Receptors

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 and chick limb bud development

Development ◽  
1991 ◽  
Vol 113 (Supplement_1) ◽  
pp. 113-121 ◽  
Author(s):  
C. Tickle
Keyword(s):  
Retinoic Acid ◽  
Target Genes ◽  
Homeobox Gene ◽  
Experimental System ◽  
Shoulder Girdle ◽  
Limb Bud ◽  
Local Concentration ◽  
Anterior Position ◽  
Mesenchyme Cells ◽  
Vitamin A Derivative

The chick limb bud is a powerful experimental system in which to study pattern formation in vertebrate embryos. Exogenously applied retinoic acid, a vitamin A derivative, can bring about changes in pattern and, on several grounds, is a good candidate for an endogenous morphogen. As such, the local concentration of retinoic acid might provide cells with information about their position in relation to one axis of the limb. Alternatively, retinoic acid may be part of a more complex signalling system. Homeobox genes are possible target genes for regulation by retinoic acid in the limb. In particular, one homeobox gene, XlHbox 1 is expressed locally in the mesenchyme of vertebrate forelimbs and might code for an anterior position. When the pattern of the chick wing is changed by retinoic acid or by grafts of signalling tissue such that anterior cells now form posterior structures, the domain of XlHbox 1 expression expands rather than contracts. The expansion of XlHbox 1 expression correlates with shoulder girdle abnormalities. Retinoic acid application leads to visible changes in bud shape and this allows dissection of the way in which patterning is co-ordinated with morphogenesis. Results of recombination experiments and studies of changes in the apical ridge and proliferation in the mesenchyme suggest the following scheme: retinoic acid is involved in specification of position of mesenchyme cells; this specification determines their local interaction with the ridge that controls ridge morphology; the thickened apical ridge permits local proliferation in the underlying mesenchyme. The recent advances in molecular biology that permit analysis of the expression of various interesting genes in developing limbs hold out the promise that further investigation may soon allow a complete account of the patterning process in one part of the vertebrate embryo.

Vitamin A alters the internal viscosity of fragments of limb-bud mesenchyme

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 325-339
Author(s):  
T. E. Kwasigroch ◽  
D. M. Kochhar
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Mesenchymal Cells ◽  
Limb Bud ◽  
Mouse Limb ◽  
Vitamin A Acid ◽  
Internal Viscosity ◽  
Fusion Experiments

Two techniques were used to examine the effect of vitamin A compounds (vitamin A acid = retinoic acid and vitamin A acetate) upon the relative strengths of adhesion among mouse limb-bud mesenchymal cells. Treatment with retinoic acid in vivo and with vitamin A acetate in vitro reduced the rate at which the fragments of mesenchyme rounded-up when cultured on a non-adhesive substratum, but these compounds did not alter the behavior of tissues tested in fragment-fusion experiments. These conflicting results indicate that the two tests measure different activities of cells and suggest that treatment with vitamin A alters the property(ies) of cells which regulate the internal viscosity of tissues.

Physical and genetic interactions between Alx4 and Cart1

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 359-369 ◽  
Author(s):  
S. Qu ◽  
S.C. Tucker ◽  
Q. Zhao ◽  
B. deCrombrugghe ◽  
R. Wisdom
Keyword(s):  
Dna Binding ◽  
Double Mutant ◽  
Biochemical Characterization ◽  
Gene Dosage ◽  
Genetic Relationships ◽  
Branchial Arch ◽  
Genetic Interactions ◽  
Limb Bud ◽  
High Affinity

Alx4 and Cart1 are closely related members of the family of transcription factors that contain the paired-type homeodomain. In contrast to other types of homeodomains, the paired-type homeodomain has been shown to mediate high-affinity sequence-specific DNA binding to palindromic elements as either homodimers or as heterodimers with other family members. Alx4 and Cart1 are co-expressed at several sites during development, including the craniofacial mesenchyme, the mesenchymal derivatives of neural crest cells in the first branchial arch and the limb bud mesenchyme. Because of the molecular similarity and overlapping expression pattern, we have analyzed the functional and genetic relationships between Alx4 and Cart1. The two proteins have similar DNA-binding activity in vitro and can form DNA-binding heterodimers; furthermore, they activate transcription of reporter genes that contain high-affinity DNA-binding sites in cell culture in a similar manner. Therefore, at least by these criteria, the two proteins are functionally redundant. Analysis of double mutant animals reveals several genetic interactions. First, mutation of Cart1 exacerbates Alx4-dependent polydactyly in a manner that is dependent on gene dosage. Second, there are complex genetic interactions in the craniofacial region that reveal a role for both genes in the fusion of the nasal cartilages and proper patterning of the mandible, as well as other craniofacial structures. Third, double mutant mice show a split sternum that is not detected in mice with any other genotype. Interpreted in the context of the biochemical characterization, the genetic analysis suggests that Alx4 and Cart1 are indeed functionally redundant, and reveal both unique and redundant functions for these genes in development.

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
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