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.

Identification of otx2 target genes and restrictions in ectodermal competence during Xenopus cement gland formation

Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 471-481 ◽  
Author(s):  
L.S. Gammill ◽  
H. Sive
Keyword(s):  
Retinoic Acid ◽  
Target Genes ◽  
Homeobox Gene ◽  
Cement Gland ◽  
Inhibitory Effects ◽  
Temporal Modulation ◽  
Downstream Target ◽  
Positional Identity ◽  
Direct Target ◽  
Differentiation Marker

The homeobox gene otx2 is a key regulator of positional identity in vertebrates, however its downstream target genes and mechanism of action are not known. We have analyzed otx2 function during formation of the Xenopus cement gland, an organ that expresses otx2. The cement gland forms at early neurula from extreme anterior ectoderm and corresponds to the chin primordium of mammals. Previous studies (Blitz, I. and Cho, K. (1995) Development 121, 993–1004; Pannese, M., Polo, C., Andreazzoli, M., Vignali, R., Kablar, B., Barsacchi, G. and Boncinelli, E. (1995) Development 121, 707–720) showed that misexpressed otx2 could activate cement gland formation. However, it was not clear whether this was a direct effect of otx2 or a secondary consequence of other tissues induced by otx2. In this study we ask whether otx2 activity is spatially and temporally restricted in the ectoderm and whether cement gland-specific genes are direct targets of otx2. In order to control the timing of otx2 activity, we constructed a dexamethasone-inducible otx2 protein (otx2-GR) by fusion with the ligand-binding domain of the glucocorticoid receptor. We conclude first, that regionally restricted factors regulate otx2 activity since otx2-GR is able to activate the cement gland markers XCG and XAG only in ventrolateral ectoderm, and never in the neural plate. Second, we show that temporal responsiveness of the ectoderm to otx2-GR is limited, beginning only at mid-gastrula but continuing as late as tailbud stages. Third, we show that otx2-GR activates expression of the cement gland differentiation marker XCG in the absence of protein synthesis, identifying a direct target of otx2. otx2-GR can also activate expression of the endogenous otx2 gene, defining an autoregulatory loop. Fourth, we show that otx2-GR is sufficient to overcome the inhibitory effects of retinoic acid on cement gland formation, indicating that this effect is caused by failure to express otx2. Corroboratively, we show that otx2 autoactivation is prevented by retinoic acid. Together, these findings suggest that otx2 directly controls cement gland differentiation, and that spatial and temporal modulation of otx2 activity limits cement gland formation to the front of the embryo.

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.

Temporal and regional differences in the expression pattern of distinct retinoic acid receptor-beta transcripts in the chick embryo

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 245-252 ◽  
Author(s):  
S.M. Smith ◽  
G. Eichele
Keyword(s):  
Retinoic Acid ◽  
In Situ Hybridization ◽  
Expression Pattern ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Receptor Gene ◽  
Regulatory Region ◽  
Limb Bud ◽  
Differential Distribution

Retinoic acid (RA) is a signaling molecule apparently involved in a variety of morphogenetic processes, such as patterning of developing and regenerating vertebrate limbs. RA binds to specific intracellular receptors that constitute a multigene family. RA receptors (RAR) bind to the regulatory region of specific target genes and thereby control the expression of these genes. Here we report the sequence and spatiotemporal expression pattern of RAR-beta from chick. Northern blots of RNA from whole embryos and from limb buds reveal the presence of transcripts of 3.2, 3.4, and 4.6 kb in size. Using two riboprobes, one that hybridizes to all three RAR-beta mRNAs and a second one, specific for the 4.6 kb transcript, we found by in situ hybridization a differential distribution of RAR-beta transcripts in limb bud mesenchyme, in craniofacial mesenchyme and in hindbrain neuroectoderm. In the hindbrain the 4.6 kb mRNA exhibits an anterior boundary of expression at the level of the constriction between rhombomeres 5 and 6. Examination of neural plate stage embryos by in situ hybridization indicates that this boundary of expression is already defined by this stage. In addition to having several RA receptors that are expressed with distinct spatial patterns in the embryo, our data indicate that the expression pattern of transcripts derived from a single receptor gene can also be differentially expressed, thus providing another level for regulating RA action.

Effect of all-trans retinoic acid and pentagalloyl glucose on smooth muscle cell elastogenesis

2021 ◽  
pp. 1-13
Author(s):  
Kaveh Sanaei ◽  
Sydney Plotner ◽  
Anson Oommen Jacob ◽  
Jaime Ramirez-Vick ◽  
Narendra Vyavahare ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Retinoic Acid ◽  
Smooth Muscle Cells ◽  
Blood Vessels ◽  
Muscle Cells ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Tissue Engineered Blood Vessels ◽  
Pentagalloyl Glucose ◽  
Vitamin A Derivative

BACKGROUND: The main objective of tissue engineering is to fabricate a tissue construct that mimics native tissue both biologically and mechanically. A recurring problem for tissue-engineered blood vessels (TEBV) is deficient elastogenesis from seeded smooth muscle cells. Elastin is an integral mechanical component in blood vessels, allowing elastic deformation and retraction in response to the shear and pulsatile forces of the cardiac system. OBJECTIVE: The goal of this research is to assess the effect of the vitamin A derivative all-trans retinoic acid (RA) and polyphenol pentagalloyl glucose (PGG) on the expression of elastin in human aortic smooth muscle cells (hASMC). METHODS: A polycaprolactone (PCL) and the gelatin polymer composite was electrospun and doped with RA and PGG. The scaffolds were subsequently seeded with hASMCs and incubated for five weeks. The resulting tissue-engineered constructs were evaluated using qPCR and Fastin assay for their elastin expression and deposition. RESULTS: All treatments showed an increased elastin expression compared to the control, with PGG treatments showing a significant increase in gene expression and elastin deposition.

Experimental analysis of the control of expression of the homeobox-gene Msx-1 in the developing limb and face

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 41-48 ◽  
Author(s):  
J.M. Brown ◽  
S.E. Wedden ◽  
G.H. Millburn ◽  
L.G. Robson ◽  
R.E. Hill ◽  
...  
Keyword(s):  
Homeobox Gene ◽  
Host Tissue ◽  
Face To Face ◽  
Limb Mesenchyme ◽  
The Face ◽  
Mesenchyme Cells ◽  
Species Specific ◽  
Signalling Systems ◽  
Control Of Expression

Mouse mesenchyme was grafted into chick embryos to investigate the control of mesenchymal expression of Msx-1 in the developing limb and face. In situ hybridization, using species-specific probes, allows a comparison between Msx-1 expression in the graft and the host tissue. The results show that Msx-1 expression in both limb-to-limb and face-to-face grafts corresponds closely with the level of Msx-1 expression in the surrounding chick mesenchyme. Cells in grafts that end up within the host domain of Msx-1 express the gene irrespective of whether they were from normally expressing, or non-expressing, regions. Therefore Msx-1 expression in both the developing limb and the developing face appears to be position-dependent. Mesenchyme from each of the three major facial primordia behaved in the same way when grafted to the chick maxillary primordium. Reciprocal grafts between face and limb gave a different result: Msx-1 expression was activated when facial mesenchyme was grafted to the limb but not when limb mesenchyme was grafted to the face. This suggests either that there are quantitative or qualitative differences in two local signalling systems or that additional factors determine the responsiveness of the mesenchyme cells.

Early embryonic expression ofFGF4/6/9gene and its role in the induction of mesenchyme and notochord inCiona savignyiembryos

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1729-1738 ◽  
Author(s):  
Kaoru S. Imai ◽  
Nori Satoh ◽  
Yutaka Satou
Keyword(s):  
Cell Differentiation ◽  
Nuclear Localization ◽  
Target Genes ◽  
Muscle Cells ◽  
Cell Stage ◽  
Ciona Savignyi ◽  
Mesenchyme Cell ◽  
Notochord Cells ◽  
Mesenchyme Cells ◽  
Endodermal Cells

In early Ciona savignyi embryos, nuclear localization of β-catenin is the first step of endodermal cell specification, and triggers the activation of various target genes. A cDNA for Cs-FGF4/6/9, a gene activated downstream of β-catenin signaling, was isolated and shown to encode an FGF protein with features of both FGF4/6 and FGF9/20. The early embryonic expression of Cs-FGF4/6/9 was transient and the transcript was seen in endodermal cells at the 16- and 32-cell stages, in notochord and muscle cells at the 64-cell stage, and in nerve cord and muscle cells at the 110-cell stage; the gene was then expressed again in cells of the nervous system after neurulation. When the gene function was suppressed with a specific antisense morpholino oligo, the differentiation of mesenchyme cells was completely blocked, and the fate of presumptive mesenchyme cells appeared to change into that of muscle cells. The inhibition of mesenchyme differentiation was abrogated by coinjection of the morpholino oligo and synthetic Cs-FGF4/6/9 mRNA. Downregulation of β-catenin nuclear localization resulted in the absence of mesenchyme cell differentiation due to failure of the formation of signal-producing endodermal cells. Injection of synthetic Cs-FGF4/6/9 mRNA in β-catenin-downregulated embryos evoked mesenchyme cell differentiation. These results strongly suggest that Cs-FGF4/6/9 produced by endodermal cells acts an inductive signal for the differentiation of mesenchyme cells. On the other hand, the role of Cs-FGF4/6/9 in the induction of notochord cells is partial; the initial process of the induction was inhibited by Cs-FGF4/6/9 morpholino oligo, but notochord-specific genes were expressed later to form a partial notochord.

scholarly journals FgHtf1 Regulates Global Gene Expression towards Aerial Mycelium and Conidiophore Formation in the Cereal Fungal Pathogen Fusarium graminearum

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Gaili Fan ◽  
Huawei Zheng ◽  
Kai Zhang ◽  
Veena Devi Ganeshan ◽  
Stephen Obol Opiyo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Gene Family ◽  
Fusarium Graminearum ◽  
Target Genes ◽  
Homeobox Gene ◽  
Global Gene Expression ◽  
Binding Motifs ◽  
Content Type ◽  
Aerial Growth

ABSTRACT The homeobox gene family of transcription factors (HTF) controls many developmental pathways and physiological processes in eukaryotes. We previously showed that a conserved HTF in the plant-pathogenic fungus Fusarium graminearum, Htf1 (FgHtf1), regulates conidium morphology in that organism. This study investigated the mechanism of FgHtf1-mediated regulation and identified putative FgHtf1 target genes by a chromatin immunoprecipitation assay combined with parallel DNA sequencing (ChIP-seq) and RNA sequencing. A total of 186 potential binding peaks, including 142 genes directly regulated by FgHtf1, were identified. Subsequent motif prediction analysis identified two DNA-binding motifs, TAAT and CTTGT. Among the FgHtf1 target genes were FgHTF1 itself and several important conidiation-related genes (e.g., FgCON7), the chitin synthase pathway genes, and the aurofusarin biosynthetic pathway genes. In addition, FgHtf1 may regulate the cAMP-protein kinase A (PKA)-Msn2/4 and Ca2+-calcineurin-Crz1 pathways. Taken together, these results suggest that, in addition to autoregulation, FgHtf1 also controls global gene expression and promotes a shift to aerial growth and conidiation in F. graminearum by activation of FgCON7 or other conidiation-related genes. IMPORTANCE The homeobox gene family of transcription factors is known to be involved in the development and conidiation of filamentous fungi. However, the regulatory mechanisms and downstream targets of homeobox genes remain unclear. FgHtf1 is a homeobox transcription factor that is required for phialide development and conidiogenesis in the plant pathogen F. graminearum. In this study, we identified FgHtf1-controlled target genes and binding motifs. We found that, besides autoregulation, FgHtf1 also controls global gene expression and promotes conidiation in F. graminearum by activation of genes necessary for aerial growth, FgCON7, and other conidiation-related genes.

scholarly journals Differences in Gene Expression between Wild Type and Hoxa1 Knockout Embryonic Stem Cells after Retinoic Acid Treatment or Leukemia Inhibitory Factor (LIF) Removal

2005 ◽  
Vol 280 (16) ◽  
pp. 16484-16498 ◽  
Author(s):  
Eduardo Martinez-Ceballos ◽  
Pierre Chambon ◽  
Lorraine J. Gudas
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Retinoic Acid ◽  
Leukemia Inhibitory Factor ◽  
Target Genes ◽  
Hox Genes ◽  
Es Cells ◽  
Embryonic Stem ◽  
Inhibitory Factor ◽  
Hoxa Cluster

Homeobox (Hox) genes encode a family of transcription factors that regulate embryonic patterning and organogenesis. In embryos, alterations of the normal pattern of Hox gene expression result in homeotic transformations and malformations. Disruption of theHoxa1gene, the most 3′ member of the Hoxa cluster and a retinoic acid (RA) direct target gene, results in abnormal ossification of the skull, hindbrain, and inner ear deficiencies, and neonatal death. We have generated Hoxa1-/-embryonic stem (ES) cells (named Hoxa1-15) from Hoxa1-/-mutant blastocysts to study the Hoxa1 signaling pathway. We have characterized in detail these Hoxa1-/-ES cells by performing microarray analyses, and by this technique we have identified a number of putative Hoxa-1 target genes, including genes involved in bone development (e.g. Col1a1,Postn/Osf2, and the bone sialoprotein gene orBSP), genes that are expressed in the developing brain (e.g. Nnat,Wnt3a,BDNF,RhoB, andGbx2), and genes involved in various cellular processes (e.g. M-RAS,Sox17,Cdkn2b,LamA1,Col4a1,Foxa2,Foxq1,Klf5, andIgf2). Cell proliferation assays and Northern blot analyses of a number of ES cell markers (e.g. Rex1,Oct3/4,Fgf4, andBmp4) suggest that the Hoxa1 protein plays a role in the inhibition of cell proliferation by RA in ES cells. Additionally, Hoxa1-/-ES cells express high levels of various endodermal markers, includingGata4andDab2, and express much lessFgf5after leukemia inhibitory factor (LIF) withdrawal. Finally, we propose a model in which the Hoxa1 protein mediates repression of endodermal differentiation while promoting expression of ectodermal and mesodermal characteristics.

scholarly journals An intrinsic cell cycle timer terminates limb bud outgrowth

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Joseph Pickering ◽  
Constance A Rich ◽  
Holly Stainton ◽  
Cristina Aceituno ◽  
Kavitha Chinnaiya ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Rna Sequencing ◽  
Late Stage ◽  
Limb Development ◽  
Limb Bud ◽  
Limb Outgrowth ◽  
Bmp Signalling ◽  
Mesenchyme Cells

The longstanding view of how proliferative outgrowth terminates following the patterning phase of limb development involves the breakdown of reciprocal extrinsic signalling between the distal mesenchyme and the overlying epithelium (e-m signalling). However, by grafting distal mesenchyme cells from late stage chick wing buds to the epithelial environment of younger wing buds, we show that this mechanism is not required. RNA sequencing reveals that distal mesenchyme cells complete proliferative outgrowth by an intrinsic cell cycle timer in the presence of e-m signalling. In this process, e-m signalling is required permissively to allow the intrinsic cell cycle timer to run its course. We provide evidence that a temporal switch from BMP antagonism to BMP signalling controls the intrinsic cell cycle timer during limb outgrowth. Our findings have general implications for other patterning systems in which extrinsic signals and intrinsic timers are integrated.

scholarly journals Effects of novel retinoid X receptor-selective ligands on myeloid leukemia differentiation and proliferation in vitro

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1977-1984 ◽  
Author(s):  
M Kizaki ◽  
MI Dawson ◽  
R Heyman ◽  
E Elster ◽  
R Morosetti ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Clonal Growth ◽  
Myeloid Leukemia ◽  
Target Genes ◽  
Synergistic Effects ◽  
Leukemic Cells ◽  
Acute Myeloid Leukemia Cells ◽  
Differentiation And Proliferation ◽  
Acute Myeloid

The biologic effects of retinoids such as all-trans-retinoic acid (ATRA) and 9-cis-retinoic acid on proliferation and differentiation of hematopoietic cells are mediated by binding and activating two distinct families of transcription factors: the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). The RARs require heterodimerization with RXRs; in addition, RXRs can form homodimers, which can bind to DNA response elements that are either distinct or the same as those bound by the RAR/RXR heterodimers. Therefore, the two retinoid pathways provide sequences that are specific for effective DNA binding and activation of target genes. We have developed several series of novel synthetic retinoids that selectively interact with RXR/RXR homodimers and RAR/RXR heterodimers. We show here that SR11236 and SR11246, which are RXR-selective analogs, had little ability to inhibit clonal growth and induce differentiation of leukemic cells (HL- 60 cells and fresh acute myeloid leukemia cells). However, SR11249, SR11256, and LGD1069, which activated both RXR/RXR homodimers and RAR/RXR heterodimers, could inhibit clonal growth and induce differentiation of HL-60 cells as well as leukemic cells from patients, including those with acute promyelocytic leukemia (APL). This is similar to results observed with RAR/RXR-specific ligands. Interestingly, the combination of ATRA and either SR11249, SR11256, or LGD1069 showed synergistic effects in inducing differentiation of HL-60 cells. A retinoid (SR11238) with strong anti-AP-1 activity that did not activate the RARs and RXRs for gene transcription from the response element TREpal was inactive in our assay systems, suggesting that the antiproliferative effects of retinoids on leukemic cells is not mediated by inhibiting the AP-1 pathway. We conclude that the RAR/RXR pathway is more important than RXR/RXR pathway for differentiation and proliferation of acute myeloid leukemic cells, and certain retinoids or combination of retinoids with both RAR and RXR specificities may synergistically enhance the differentiation activity of ATRA, which may be relevant in several clinical situations.

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