Ectopic expression of Hoxa-1 in the zebrafish alters the fate of the mandibular arch neural crest and phenocopies a retinoic acid-induced phenotype

Development ◽  
1996 ◽  
Vol 122 (3) ◽  
pp. 735-746 ◽  
Author(s):  
D. Alexandre ◽  
J.D. Clarke ◽  
E. Oxtoby ◽  
Y.L. Yan ◽  
T. Jowett ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Neural Crest ◽  
Ectopic Expression ◽  
Head Region ◽  
Hox Gene ◽  
Abnormal Growth ◽  
Primary Body ◽  
Arch Neural ◽  
The Relationship

Considerable evidence has demonstrated that retinoic acid influences the formation of the primary body axis in vertebrates and that this may occur through the regulation of Hox gene expression. In this study, we show that the phenotype induced by exogenous retinoic acid in the zebrafish can also be generated by the overexpression of Hoxa-1 following injection of synthetic RNA into the fertilised egg. The isolation, sequence and expression pattern of the zebrafish Hoxa-1 gene is described. We show that exogenously applied retinoic acid causes the ectopic accumulation of Hoxa-1 message during gastrulation in the hypoblast in the head region. Overexpression of Hoxa-1 following injection of RNA causes abnormal growth of the anterior hindbrain, duplication of Mauthner neurons in rhombomere (r) 2 and fate changes of r2 mesenchymal and neurogenic neural crest. These results are discussed in terms of the role of Hoxa-1 in controlling anterior hindbrain patterning and the relationship between expression of Hoxa-1 and retinoic acid.

Role of the chicken homeobox-containing genes GHox-4.6 and GHox-8 in the specification of positional identities during the development of normal and polydactylous chick limb buds

Development ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 629-637 ◽  
Author(s):  
C.N. Coelho ◽  
W.B. Upholt ◽  
R.A. Kosher
Keyword(s):  
Limb Development ◽  
Ectopic Expression ◽  
Limb Bud ◽  
Chick Embryos ◽  
Limb Buds ◽  
Hox Gene ◽  
Wing Bud ◽  
Coated Bead ◽  
Experimentally Induced

During early stages of normal chick limb development, the homeobox-containing (HOX) gene GHox-4.6 is expressed throughout the posterior mesoderm of the wing bud from which most of the skeletal elements including the digits will develop, whereas GHox-8 is expressed in the anterior limb bud mesoderm which will not give rise to skeletal elements. In the present study, we have examined the expression of GHox-4.6 and GHox-8 in the wing buds of two polydactylous mutant chick embryos, diplopodia-5 and talpid2, from which supernumerary digits develop from anterior limb mesoderm, and have also examined the expression of these genes in response to polarizing zone grafts and retinoic acid-coated bead implants which induce the formation of supernumerary digits from anterior limb mesoderm. We have found that the formation of supernumerary digits from the anterior mesoderm in mutant and experimentally induced polydactylous limb buds is preceded by the ectopic expression of GHox-4.6 in the anterior mesoderm and the coincident suppression of GHox-8 expression in the anterior mesoderm. These observations suggest that the anterior mesoderm of the polydactylous limb buds is “posteriorized” and support the suggestion that GHox-8 and GHox-4.6, respectively, are involved in specifying the anterior non-skeletal and posterior digit-forming regions of the limb bud. Although the anterior mesodermal domain of GHox-8 expression is severely impaired in the mutant and experimentally induced polydactylous limb buds, this gene is expressed by the prolonged, thickened apical ectodermal ridges of the polydactylous limb buds that extend along the distal anterior as well as the distal posterior mesoderm.(ABSTRACT TRUNCATED AT 250 WORDS)

Developmental role of endogenous retinoids in the determination of morphallactic field in budding tunicates

Development ◽  
1993 ◽  
Vol 117 (3) ◽  
pp. 835-845 ◽  
Author(s):  
K. Kawamura ◽  
K. Hara ◽  
S. Fujiwara
Keyword(s):  
Retinoic Acid ◽  
Aldehyde Dehydrogenase ◽  
Ectopic Expression ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Proximal Extremity ◽  
Developmental Role

We have extracted retinoids from the budding tunicate Polyandrocarpa misakiensis and, using HPLC, identified some major peaks as cis-retinal, all-trans-retinal and all-trans-retinoic acid, of which cis-retinal was most abundant (~2 micromolar). In developing buds, the amount of cis-retinal was about one-fifth that of the adult animals. In those buds, aldehyde dehydrogenase, which could metabolize retinal in vitro, was expressed in epithelial cells and then in mesenchymal cells at the proximal extremity, that is, the future developmental field of the bud. Exogenous retinoic acid comparable to the endogenous level could induce an additional field at the distal end of the bud, resulting in a double monster. The induction always accompanied an ectopic expression of aldehyde dehydrogenase. The results of this work suggest that retinoic acid or related molecule(s) act as an endogenous trigger of morphallactic development of Polyandrocarpa buds.

scholarly journals CDPK6 phosphorylates and stabilizes MYB30 to promote hyperoside biosynthesis that prolongs the duration of full-blooming in okra

2020 ◽  
Vol 71 (14) ◽  
pp. 4042-4056
Author(s):  
Qing Yang ◽  
Biying Dong ◽  
Litao Wang ◽  
Zhihua Song ◽  
Lili Niu ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Fold Increase ◽  
Bimolecular Fluorescence Complementation ◽  
Dependent Manner ◽  
Flavonoid Pathway ◽  
Calcium Dependent ◽  
Key Enzyme ◽  
Dependent Protein ◽  
The Relationship

Abstract The flowers of okra (Abelmoschus esculentus) open and wilt within only a few hours, and this is accompanied by accumulation of hyperoside, a secondary metabolite in the flavonoid pathway. However, little is known about the relationship between flavonoids and flowering. Here, we found that exogenous application of hyperoside extended the duration of the full-blooming period by more than 3-fold, and this was accompanied by a 14.7-fold increase in the expression of CALCIUM-DEPENDENT PROTEIN KINASE6 (AeCDPK6). Gene expression profiling indicated that the transcription factor AeMYB30 was co-expressed with AeCDPK6, and detailed protein interaction and phosphorylation experiments together with yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated an interaction between AeMYB30 and AeCDPK6. AeCDPK6 specifically phosphorylated AeMYB30S191, leading to increased protein stability and prevention of degradation. Furthermore, AeMYB30 directly bound to the promoter of AeUF3GaT1, a key enzyme in the hyperoside biosynthesis pathway. Analysis of transgenic plants showed that AeCDPK6 was required for the hyperoside-induced phosphorylation of AeMYB30 to enhance its stability and transcriptional activity. Ectopic expression of AeCDPK6 promoted hyperoside accumulation and prolonged the full-blooming period in an AeMYB30-dependent manner. Our results indicate the role of AeCDPK6–AeMYB30 in the molecular mechanism by which hyperoside regulates the period of full blooming in okra, a plant with a short duration of flowering.

Late effects of retinoic acid on neural crest and aspects of rhombomere

Development ◽  
1996 ◽  
Vol 122 (3) ◽  
pp. 783-793 ◽  
Author(s):  
E. Gale ◽  
V. Prince ◽  
A. Lumsden ◽  
J. Clarke ◽  
N. Holder ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Neural Crest ◽  
Normal Development ◽  
Ectopic Expression ◽  
Cell Type ◽  
Dramatic Decrease ◽  
Experimental Animals ◽  
Morphological Segmentation ◽  
Neural Crest Migration ◽  
Neuronal Type

We exposed st.10 chicks to retinoic acid (RA), both globally, and locally to individual rhombomeres, to look at its role in specification of various aspects of hindbrain derived morphology. Previous studies have looked at RA exposure at earlier stages, during axial specification. Stage 10 is the time of morphological segmentation of the hindbrain and is just prior to neural crest migration. Rhombomere 4 localised RA injections result in specific alterations of pathways some crest cells that normally migrate to sites of differentiation of neurogenic derivatives. The r4 crest cells that give rise to mesenchymal derivatives are unaffected. In addition, r4 gene expression is also partially altered by RA; within 6 hours of r4 exposure to RA, ectopic expression of Krox-20 is seen in r4 and Hoxb-1 expression is lost while Hoxa-2 expression continues normally. When we examined these RA-treated animals later in development, they showed an anterior displacement of the facial ganglion in addition to a mis-direction of the extensions of its distal axons and a dramatic decrease in the number of contralateral vestibuloacoustic neurons normally seen in r4. Only this r4-specific neuronal type is affected in r4; the motor neuron projections seem normal in experimental animals. The specificity of this result, combined with the loss of Hoxb-1 expression in r4 and the work by Krumlauf and co-workers showing gain of contralateral neurons co-localised with ectopic Hoxb-1 expression, indicates a role for Hoxb-1 and RA in the specification of this cell type in normal development. These results suggest that RA, at st.10, is able to affect some aspects of segment identity while leaving others unchanged.

scholarly journals Critical Role of Cys168 in Noggin Protein's Biological Function

2005 ◽  
Vol 37 (3) ◽  
pp. 181-185
Author(s):  
Wei-Dong Liu ◽  
Xiang-Ling Feng ◽  
Cai-Ping Ren ◽  
Jian-Ling Shi ◽  
Xu-Yu Yang ◽  
...  
Keyword(s):  
Biological Activities ◽  
Critical Role ◽  
Ectopic Expression ◽  
Disulfide Bridge ◽  
Site Directed Mutagenesis ◽  
Morphogenetic Protein ◽  
Neural Cell Adhesion ◽  
A Site ◽  
The Relationship

Abstract Previous that noggin exerts its neural inducing effect by binding and antagonizing bone morphogenetic protein 4 (BMP4). In order to further clarify the relationship between the structure and the function of noggin, and elucidate the possible mechanism responsible for noggin-BMP4 interaction, we generated three noggin mutants, C168S, C174S and C197S, by using a site-directed mutagenesis method. Ectopic expression of wild-type (WT) noggin, C174S or C197S, in Xenopus animal caps (ACs) by mRNA injection converted the explants (prospective ectoderm) into neural tissue, as indicated by the neural-like morphology and expression of the neural cell adhesion molecule (NCAM) in the ACs. In contrast, ACs expressing C168S suffered an epidermal fate similar to the control caps. Similarly, among the three mutants, only C168S lost the dorsalizing function. These studies highlight the critical role played by Cys168 in noggin's biological activities. It probably participates in the formation of an intermolecular disulfide bridge.

scholarly journals Role of PPARs and Retinoid X Receptors in the Regulation of Lung Maturation and Development

PPAR Research ◽  
2007 ◽  
Vol 2007 ◽  
pp. 1-8 ◽  
Author(s):  
Dawn M. Simon ◽  
Thomas J. Mariani
Keyword(s):  
Retinoic Acid ◽  
Lung Development ◽  
Health It ◽  
Lung Maturation ◽  
Acid Pathway ◽  
X Receptors ◽  
Lung Health ◽  
The Relationship ◽  
Acid Function

Understanding lung development has significant importance to public health because of the fact that interruptions in the normal developmental processes can have prominent effects on childhood and adult lung health. It is widely appreciated that the retinoic acid (RA) pathway plays an important role in lung development. Additionally, PPARs are believed to partner with receptors of this pathway and therefore could be considered extensions of retinoic acid function, including during lung development. This review will begin by introducing the relationship between the retinoic acid pathway and PPARs followed by an overview of lung development stages and regulation to conclude with details on PPARs and the retinoic acid pathway as they may relate to lung development.

Defective lens fiber differentiation and pancreatic tumorigenesis caused by ectopic expression of the cellular retinoic acid-binding protein I

Development ◽  
1993 ◽  
Vol 119 (2) ◽  
pp. 363-375
Author(s):  
A.V. Perez-Castro ◽  
V.T. Tran ◽  
M.C. Nguyen-Huu
Keyword(s):  
Retinoic Acid ◽  
Binding Proteins ◽  
Binding Protein ◽  
Ectopic Expression ◽  
Retinoic Acid Receptors ◽  
Acid Binding Protein ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Retinoic Acid Binding Proteins

All-trans retinoic acid, a metabolite of retinol, is a possible morphogen in vertebrate development. Two classes of cellular proteins, which specifically bind all-trans retinoic acid, are thought to mediate its action: the nuclear retinoic acid receptors (RAR alpha, beta, gamma), and the cytoplasmic binding proteins known as cellular retinoic acid-binding proteins I and II (CRABP I and II). The function of the retinoic acid receptors is to regulate gene transcription by binding to DNA in conjunction with the nuclear retinoid X receptors (RXR alpha, beta, gamma), which in turn have 9-cis retinoic acid as a ligand. Several lines of evidence suggest that the role of the cellular retinoic acid-binding proteins is to control the concentration of free retinoic acid reaching the nucleus in a given cell. Here, we have addressed the role of the cellular retinoic acid-binding protein I in development by ectopically expressing it in the mouse lens, under the control of the alpha A-crystallin promoter. We show that this ectopic expression interferes with the development of the lens and with the differentiation of the secondary lens fiber cells, causing cataract formation. These results suggest that correct regulation of intracellular retinoic acid concentration is required for normal eye development. In addition, the generated transgenic mice also present expression of the transgene in the pancreas and develop pancreatic carcinomas, suggesting that overexpression of the cellular retinoic acid-binding protein is the cause of the tumors. These results taken together provide evidence for a role of the cellular retinoic acid-binding protein in development and cell differentiation. The relevance of these findings to the possible role of the cellular retinoic acid-binding proteins in the transduction of the retinoic acid signal is discussed.

The relationship of decapentaplegic and engrailed expression in Drosophila imaginal disks: do these genes mark the anterior-posterior compartment boundary?

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 27-33 ◽  
Author(s):  
L.A. Raftery ◽  
M. Sanicola ◽  
R.K. Blackman ◽  
W.M. Gelbart
Keyword(s):  
Reporter Gene ◽  
Ectopic Expression ◽  
Reporter Genes ◽  
Imaginal Disk ◽  
Compartment Boundary ◽  
Imaginal Disks ◽  
Relationship Of ◽  
The Relationship ◽  
Gene Expressing

Imaginal disks, the primordia of the adult appendages in Drosophila, are divided into anterior and posterior compartments. However, the developmental role of such compartments remains unclear. The expression of decapentaplegic (dpp), a pattern formation gene required for imaginal disk development, has the intriguing property of being expressed in a line at or near the boundary between these compartments. Here, we compare the distribution of dpp-driven reporter gene expression to the pattern of expression of the engrailed (en) gene, known to be required for the maintenance of the compartment boundary. Using confocal microscopy to obtain single cell resolution, we have determined that the majority of the en+ imaginal disk cells expressing the dpp-driven reporter genes about those cells expressing en, while a small percentage of dpp reporter gene expressing cells also express en. In posterior regions of en mutant disks, where compartmentalization is abnormal, we observe ectopic expression of the dpp-driven reporter genes. We conclude that the pattern of dpp expression in imaginal disks is delimited in part through the direct or indirect repression by engrailed. Our results lead us to question the widely held assumption that the anterior edge of en expression demarcates the A/P compartment boundary.

Retinoic acid-binding protein, rhombomeres and the neural crest

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 35-43 ◽  
Author(s):  
M. Maden ◽  
P. Hunt ◽  
U. Eriksson ◽  
A. Kuroiwa ◽  
R. Krumlauf ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Neural Crest ◽  
Neural Tube ◽  
Binding Protein ◽  
Homeobox Genes ◽  
Temporal Distribution ◽  
Stripe Pattern ◽  
Acid Binding Protein ◽  
Branchial Arches ◽  
The Relationship

We have investigated by immunocytochemistry the spatial and temporal distribution of cellular retinoic acid-binding protein (CRABP) in the developing nervous system of the chick embryo in order to answer two specific questions: do neural crest cells contain CRABP and where and when do CRABP-positive neuroblasts first arise in the neural tube? With regard to the neural crest, we have compared CRABP staining with HNK-1 staining (a marker of migrating neural crest) and found that they do indeed co-localise, but cephalic and trunk crest behave slightly differently. In the cephalic region in tissues such as the frontonasal mass and branchial arches, HNK-1 immunoreactivity is intense at early stages, but it disappears as CRABP immunoreactivity appears. Thus the two staining patterns do not overlap, but are complementary. In the trunk, HNK-1 and CRABP stain the same cell populations at the same time, such as those migrating through the anterior halves of the somites. In the neural tube, CRABP-positive neuroblasts first appear in the rhombencephalon just after the neural folds close and then a particular pattern of immunoreactivity appears within the rhombomeres of the hindbrain. Labelled cells are present in the future spinal cord, the posterior rhombencephalon up to rhombomere 6 and in rhombomere 4 thus producing a single stripe pattern. This pattern is dynamic and gradually changes as anterior rhombomeres begin to label. The similarity of this initial pattern to the arrangement of certain homeobox genes in the mouse stimulated us to examine the expression of the chicken Hox-2.9 gene. We show that at stage 15 the pattern of expression of this gene is closely related to that of CRABP. The relationship between retinoic acid, CRABP and homeobox genes is discussed.

Expression of the labial group Hox gene HrHox-1 and its alteration induced by retinoic acid in development of the ascidian Halocynthia roretzi

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3197-3205 ◽  
Author(s):  
Y. Katsuyama ◽  
S. Wada ◽  
S. Yasugi ◽  
H. Saiga
Keyword(s):  
Retinoic Acid ◽  
Molecular Mechanisms ◽  
Ectopic Expression ◽  
Vertebrate Development ◽  
Halocynthia Roretzi ◽  
Regulation Of Expression ◽  
Hox Gene ◽  
Spatial Regulation ◽  
All Trans Retinoic Acid ◽  
Developmental Features

Ascidian embryogenesis shares several developmental features with vertebrates. Thus, it is presumed that some molecular mechanisms that are critical for vertebrate development may also act in the early development of ascidians. Here, we investigated expression of the ascidian labial group Hox gene HrHox-1 in the development of Halocynthia roretzi. HrHox-1 showed a spatially restricted expression pattern along the anterior-posterior axis, which is remarkably similar to that of the vertebrate gene, Hoxb-1. The expression of HrHox-1, however, was exclusively in tissues of ectoderm origin unlike its vertebrate counterpart. Exposure of the embryos to 10(−6) M all-trans retinoic acid induced a larval phenotype with elimination of the anteriormost structures, the papillae. In this phenotype, the level of HrHox-1 expression was enhanced and ectopic expression was observed at the anterior terminal epidermis where the papillae are otherwise formed. These observations suggest that there are some conserved mechanisms in the spatial regulation of expression of labial group genes in embryogenesis of ascidians and vertebrates.

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