SEARCH · PubMed Health

Results for “inner ectoderm”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources

PubMed2006

Basement membrane heterogeneity during chick development as shown by tomato (Lycopersicon esculentum) lectin binding.

Basement membranes (BMs) constitute a distinct compartment of the extracellular matrix (ECM). All BMs show a similar structural appearance but differ in molecular composition. These variations have critical functional implications. The aim of this study is to establish the pattern of the tomato lectin (Lycopersicon esculentum agglutinin--LEA) binding sites in the BMs of the developing chick embryo (stages 4-21, Hamburger and Hamilton, 1951) in order to achieve a better understanding of the molecular heterogeneity of BMs. The study was performed with transmission electron microscopy (TEM) histochemistry, and confocal laser microscopy. TEM showed that LEA bound to the lamina densa and to the lamina fibroreticularis of the BMs. Through the period studied, most of the LEA binding appeared in the ectodermal BM and its derivatives. In the limb bud, LEA binding to the ectoderm BM was more intense in the ventral half than in the dorsal half. Furthermore, LEA allowed the early (HH16) detection of the transverse fibrillar tracts. In the lens and in the inner ear primordium, the BMs were LEA positive through the placode and cup stages. The binding was progressively reduced through the vesicle stage. The BMs of the olfactory primordium, and of the Rathke's pouch were positive. In contrast, the BMs of the developing central nervous system were negative. The BMs of both the paraxial and the lateral plates of the mesoderm were negative, whereas the notochord and the BM of the Wolffian duct were positive. The endodermal BM and its derivatives were negative. The ECM located between the fusing endocardial tubes, and the BM of the fusion zone of the paired aortae, were positive. This suggested an active role of the LEA-positive glycoproteins in the fusion of endothelia. Our results show the heterogeneity of the chick embryo BMs during development. In addition, LEA constitutes an excellent marker for the primordial germ cells.

Animals↗

PubMed1980

Monoclonal antibodies against trophectoderm-specific markers during mouse blastocyst formation.

Two-dimensional gel electrophoresis has allowed the detection of proteins characteristic of inner cell mass and trophectoderm in mouse blastocyst. Certain of the proteins characterizing trophectoderm copurify with intermediate filaments from trophectoderm and a trophoblastoma cell line. A monoclonal antibody prepared against proteins of these intermediate filaments labels a filament network in trophectoderm but not in inner cell mass cells.

Animals↗

PubMed2002

Trophectoderm growth and bilateral symmetry of the blastocyst in the mouse.

BACKGROUND: The present study was undertaken to ascertain whether the polarized flow of cells from polar to mural trophectoderm is related to the axis of bilateral symmetry of the blastocyst in the mouse, and whether trophectoderm cells can initiate new cycles once they have left the polar region. METHODS AND RESULTS: Two different approaches were used to investigate the relationship of polar to mural flow of trophectoderm cells to the bilateral axis. One was to mark peripheral polar trophectoderm cells at one or both ends of the bilateral axis in early blastocysts and examine the distribution of their clonal descendants after further growth in culture. The other was to mark the two ends of the bilateral axis with small oil drops in the zona pellucida in blastocysts whose polar trophectoderm was then labelled globally with fluorescent latex microspheres before culture. In both cases, marking of additional blastocysts orthogonal to the bilateral axis was also done. The results show that the direction of polar to mural flow of cells is not random, and that the most distal mural trophectoderm cell could yield up to eight descendants during 45 h of culture. CONCLUSION: The findings are consistent with the polar to mural flow of trophectoderm cells being aligned with the bilateral axis. Moreover, trophectoderm cells can embark on new cycles even when remote from the inner cell mass.

Animals↗

PubMed2001

Expression of Set-alpha during morphogenesis of mouse lower first molar.

The detailed in situ expression pattern of the Set-alpha gene has been studied. Previously we showed that Set-alpha is a differentially expressed gene in the embryonic mouse mandible at day 10.5 (E10.5) gestational age. Cells expressing Set-alpha were widely distributed in both the epithelial and underlying ectomesenchymal cells at E10.5. At E12, they were slightly aggregated in an area where tooth germ of the lower first molar is estimated to be formed. At E13.5, Set-alpha was strongly expressed in the tooth germ. At the cap stage, Set-alpha was expressed in the enamel organ and dental papilla. At the bell stage, Set-alpha was distinctly expressed in the inner enamel epithelial and dental papilla cells facing the inner enamel epithelial layer, which were intended to differentiate into ameloblasts and odontoblasts, respectively. Interestingly, Set-alpha was also expressed in several embryonic craniofacial tissues derived from the ectoderm. This study is the first report that Set-alpha is distinctly expressed in the developing tooth germ, and suggests that Set-alpha plays an important role in both the initiation and the growth of the tooth germ, as well as in the differentiation of ameloblasts and odontoblasts.

Animals↗

PubMed2003

Expression of ZIC genes in the development of the chick inner ear and nervous system.

ZIC genes, vertebrate homologues of the Drosophila pair-rule gene odd-paired (opa), function in embryonic pattern formation, in the early stages of central nervous system neurogenesis and in cerebellar maturation. Mouse Zic genes are expressed in restricted, and in some cases overlapping, patterns during development, particularly in the central and peripheral nervous systems. We identified chick ZIC2 in a differential display analysis of the auditory system designed to find genes up-regulated after noise trauma. In this study, we examined the expression of chick ZIC1, ZIC2, and ZIC3 by in situ hybridization in normal inner ear development and in the tissues that influence its development, including the hindbrain, the neural crest, and the periotic mesenchyme. Between Hamburger and Hamilton stages 13 and 24, all three ZIC genes were found in the dorsal periotic mesenchyme adjacent to the developing inner ear. ZIC1 mRNA was expressed in the otocyst epithelium between stages 12 and 24, in some sensory tissue, as well as in a striped pattern in the floorplate of the hindbrain that appears to be complementary to that of Chordin, a gene known to regulate ZIC expression in frogs. Chick ZIC genes are also expressed in the neuroectoderm, paraxial mesenchyme, brain, spinal cord, neural crest, and/or the overlying ectoderm as well as the limb buds. In general, ZIC1 and ZIC2 expression patterns overlapped, although ZIC2 expression was less robust; ZIC3 expression was minimal. These observations suggest that ZIC genes, in addition to their known roles in brain development, may play an important role in the development of the chick inner ear.

Animals↗

PubMed1990

[Immunohistochemical localization of transforming growth factor beta-1 during the early mouse development].

The distribution of transforming growth factor beta-1 (TGF-beta-1) in the early developing mouse embryos between day 1 and day 12 of gestation was examined by immunohistochemical techniques. Polyclonal rabbit antiserum raised against a synthetic oligopeptide identical to the N-terminal residues 1-29 of TGF-beta-1 from human platelets was used. The following results were obtained: 1. Embryonic cells of early cleavage stages (2, 4 and 8 cells) and late morulae showed positive immunofluorescent reaction without any difference in staining intensity (Plate I, Figs. 1-4). 2. Marked staining of blastocysts in toto or sections with anti-TGF-beta-1 antibodies by either immunofluorescence or immunoperoxidase reaction was also observed. Inner cell mass (ICM) cells and trophoectoderm cells were both reacted, but more intense staining was found in primary endoderm cells differentiated from ICM cells adjacent to blastocoele (Plate II, Fig. 5). 3. Scattered granules stained strongly with immunoperoxidase reaction were present in embryonic ectoderm and visceral endoderm surrounding the forming mesoderm which was only slightly stained (Plate II, Fig. 6). 4. Intense immunoperoxidase staining was also present in mesoderm of visceral yolk sac of day 8 and day 10 embryos (Plate II, Fig. 7). 5. During the formation of somites, neural tube and limb bud, remarkable staining was found in mesenchyme, individual cells of somites, mucous layer of gut tubes, heart and limb buds (Plate III, Figs. 8-10). No significant staining was seen in neural cells per se except the inner surface of neural tube. The results of present studies indicate that abundant TGF-beta-1 is present in preimplantation mouse embryos including cleavage, morulae and blastocyst stages. In postimplantation embryos, TGF-beta-1 appears to play an important role in the differentiation of endoderm and mesoderm, particularly in the development of extraembryonic tissues, and in later morphogenetic and histogenetic events involving mainly mesoderm or mesenchyme cells.

Animals↗

PubMed2004

Distribution and structure of dental enamel in incisors of Tabby mice.

OBJECTIVE: In Tabby mice, the Ta (EDA) gene is mutated. The resulting syndrome is homologous to hypohidrotic ectodermal dysplasia in humans. The Tabby phenotype is characterized by developmental defects of ectodermally derived structures. The teeth show aberrations in number, size and morphology. Dental enamel is a product of specialized epithelial cells, the ameloblasts. It was the aim of the present study to investigate the dental enamel phenotype in Tabby incisors, with emphasis on its distribution and structure. DESIGN: The incisors from five female Tabby and three female wild-type mice were sectioned and ground transversely, etched for 45s with 0.1% nitric acid, sputter-coated with gold-palladium, and observed in SEM. RESULTS: All measured dimensions were more variable in Tabby mice, as was the outline of the enamel-dentin junction. Maxillary incisors were wider in Tabby mice, while mandibular incisors were wider in wild-type mice. No significant difference in enamel thickness was observed. The enamel on the mesial aspect tended to extend further lingually in Tabby incisors in both jaws. On the lateral aspect, this tendency was only significant in mandibular incisors. The enamel-dentin junction often lacked the mesial concavity. Instances of hypoplastic enamel were observed. The complex mouse enamel structure was generally well preserved in Tabby mice, only few instances of aberrant structure were observed. CONCLUSIONS: It is suggested that the reciprocal expression pattern of Ta and Edar (the Ta ligand receptor gene) in outer and inner enamel epithelium, respectively, may influence the position of the enamel-cementum junction.

Animals↗

PubMed1979

Development of velvet coat (Ve/Ve), another early lethal mutation in the house mouse.

A new semidominant mutation in the house mouse, velvet coat (Ve), is described. Ve homozygotes, recognizable on day 5 of gestation by their deficiency of ectodermal cells, never produce mesoderm and are resorbed by days 9-10. Primary Ve action may occur during the formation of the blastocyst or during determination and differentiation of the inner cell mass, or both. Accordingly, Ve/Ve embryos may provide a useful model for investigating primary gene action during blastocyst formation and subsequent differentiation.

Animals↗

PubMed1993

Ontogeny of hyaluronan secretion during early mouse development.

The ontogeny of hyaluronan (HA) secretion during early mouse embryogenesis has been investigated using a biotin-labelled HA-binding complex from cartilage proteoglycan. HA is first secreted by visceral endoderm cells of the early egg cylinder on day 5.5 post coitum (p.c.), predominantly into the expanding yolk cavity. On day 6.5 p.c., HA is present in both the yolk and proamniotic cavities, but pericellular staining is restricted to the visceral endoderm and a population of embryonic ectoderm cells at the antimesometrial end of the proamniotic cavity. By the primitive streak stage, HA is secreted into the ectoplacental, exocoelomic, amniotic and yolk cavities, whilst the only cells exhibiting pericellular staining are those of the embryonic and extraembryonic mesoderm, including the allantois. Comparisons of HA-staining patterns of cultured whole blastocysts, microdissected trophectoderm fragments and immunosurgically isolated inner cell masses, revealed no trophoblast-associated HA secretion during outgrowth in vitro but significant synthetic activity by the endodermal derivatives of differentiating inner cell masses. To identify the cell lineages responsible for secretion of HA into the embryonic cavities and to investigate the origin of the HA observed around migrating mesoderm cells, day 7.5 p.c. primitive streak stage conceptuses were dissected into their various embryonic and extraembryonic cell lineages. HA secretion was observed after short-term suspension culture of mesoderm, embryonic ectoderm and embryonic endoderm, but was undetectable in fragments of ectoplacental cone, parietal yolk sac (primary giant trophoblast and parietal endoderm), extraembryonic ectoderm or extraembryonic endoderm. The level of synthesis by the HA-positive tissues was markedly enhanced by culture in medium containing serum, compared with that obtained following culture in medium supplemented with a defined serum substitute containing insulin, transferrin, selenous acid and linoleic acid. This suggests that additional growth factors, present in serum but absent from the serum substitute, are required for optimal HA synthesis by the HA-secreting tissues in vitro, and probably also in vivo. The implications of these events for implantation and the development of peri- and early post-implantation mouse embryos are discussed, and a new role for HA in the initial formation and expansion of the embryonic cavities is proposed.

Animals↗

PubMed1992

Embryology of the eye and its adnexae.

The embryonal and fetal development of the human eye includes a series of sequential events starting with the fertilization of the ovum and culminating in the birth of a normal baby. Three main periods can be distinguished in the prenatal development of the eye. The first period called embryogenesis is characterized by the establishment of the primary organ rudiments and ends at the end of the 3rd week with the appearance of the optic sulci on both sides of the midline at the expanded cranial end of the still open neural folds. The second period called organogenesis includes the development of the primary organ rudiments and extends till the end of the 8th week. The third period involves the differentiation of each of the primitive organs into a fully or partially active organ and is called differentiation. The period of embryogenesis is characterized by the appearance and migration of the neural crest cells and by the formation of the primary brain vesicles. The period of organogenesis extends from the 4th week till the end of the 8th week. The 4th week shows the closure of the neural canal anteriorly with the subsequent evagination of its lateral wall into optic vesicles, the invagination of the lower nasal wall of the optic vesicle causing the formation of the optic cup, and the development of the lens plate, retinal disk and embryonic fissure. The embryonic fissure extends into the optic stalk which connects the cavity of the optic vesicle with the cavity of the neural canal; the hyaloid artery penetrates into the optic cup through the embryonic fissure. During the 5th week, the optic cup is concluded, and the cells of its external layer acquire pigmentation as a result of contact with developing capillaries in the periocular mesenchyme; these capillaries anastomose with each other and form anteriorly the annular vessel. The lens plate develops into a lens pit and later into a lens vesicle which separates soon thereafter from the surface ectoderm. Inside the optic cup, the hyaloid vessels form the capillaries of the posterior tunica vasculosa lentis and through the capillaries of the lateral tunica vasculosa lentis anastomose with the annular vessel. The primary vitreous forms and the surface ectoderm overlying the lens vesicle differentiates into a primitive corneal epithelium. The facial and orbital structures also develop at this stage. The 6th week shows the incipient differentiation of the inner layer of the optic cup into a sensory retina, the formation of the secondary vitreous, the transformation of the posterior cells of the lens vesicle into primary lens fibers, the development of the periocular vasculature and the appearance of the first eyelid folds and of the anlage of the nasolacrimal duct. However, the dominating factor is the closure of the embryonic fissure.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Differentiation↗

PubMed2002

Expression patterns of focal adhesion associated proteins in the developing retina.

Adhesive interactions between integrin receptors and the extracellular matrix (ECM) are intimately involved in regulating development of a variety of tissues within the organism. In the present study, we have investigated the relationships between beta(1) integrin receptors and focal adhesion associated proteins during eye development. We used specific antibodies to examine the distribution of beta(1) integrin ECM receptors and the cytoplasmic focal adhesion associated proteins, talin, vinculin, and paxillin in the developing Xenopus retina. Immunoblot analysis confirmed antibody specificity and indicated that beta(1) integrins, talin, vinculin, and paxillin were expressed in developing retina and in the retinal-derived Xenopus XR1 glial cell line. Triple-labeling immunocytochemistry revealed that talin, vinculin, paxillin, and phosphotyrosine proteins colocalized with beta(1) integrins at focal adhesions located at the termini of F-actin filaments in XR1 cells. In the retina, these focal adhesion proteins exhibited developmentally regulated expression patterns during eye morphogenesis. In the embryonic retina, immunoreactivities for focal adhesion proteins were expressed in neuroepithelial cells, and immunoreactivity was especially strong at the interface between the optic vesicle and overlying ectoderm. At later stages, these proteins were expressed throughout all retinal layers with higher levels of expression observed in the plexiform layers, optic fiber layer, and in the region of the inner and outer limiting membrane. Strong immunoreactivities for beta(1) integrin, paxillin, and phosphotyrosine were expressed in the radially oriented Müller glial cells at later stages of development. These results suggest that focal adhesion-associated proteins are involved in integrin-mediated adhesion and signaling and are likely to be essential in regulating retinal morphogenesis.

Animals↗

PubMed1984

Expression of a glucose-regulated cell surface protein in early mouse embryos.

A 100,000-Da glucose-regulated surface protein (100K-GRP) has previously been isolated from the cell surface and culture medium of human fibroblasts. A rabbit antiserum directed against this protein reacts with the cell surface of both human and murine cultured cells and with a broad spectrum of mammalian tissues. It is shown, via indirect immunofluorescence, that this protein is also present on cells of the developing mouse embryo and can be detected as early as the 4-cell stage. The 8-cell embryo and morula show positive surface labeling; the inner cell masses of both the pre- and postimplantation blastocysts are also positive but the trophectoderm is not. At the 6-day egg cylinder stage, the embryonic and extra-embryonic ectoderm label intensely with the antiserum and visceral endoderm shows faint labeling. No labeling can be detected on parietal endoderm or on the trophoblastic giant cells invading the uterine decidua. However, the internal cells of the ectoplacental cone exhibit bright fluorescence. The same pattern is observed on 7- to 8.5-day embryos, except that at this stage no label is associated with the visceral endoderm. In addition, mesodermal cells emerging from the primitive streak are also labeled.

Animals↗

PubMed2004

Erk2 signaling and early embryo stem cell self-renewal.

Differentiation of the mammalian blastocyst generates two distinct cell lineages: the trophectoderm, which contributes to the trophoblast layers of the placenta, and the inner cell mass, which forms the embryo. We and others recently demonstrated that the MAP kinase ERK2 is essential for trophoblast development. Erk2 mutant embryos fail to form extra-embryonic ectoderm and the ectoplacental cone, suggesting a role for ERK2 activation in the proliferation of trophoblast stem (TS) cells. Previous studies have documented that ERK1/2 activity is dispensable for proliferation of embryonic stem (ES) cells and rather interferes with self-renewal. Thus, signaling by the ERK1/2 MAP kinase pathway appears to be critical for the regulation of self-renewal and propagation of early embryo stem cell populations.

Animals↗

PubMed1978

In vitro development of inner cell masses isolated immunosurgically from mouse blastocysts. I. Inner cell masses from 3.5-day p.c. blastocysts incubated for 24 h before immunosurgery.

This paper describes the in vitro development of inner cell masses isolated immunosurgically from mouse blastocysts which had been collected on 3.5 days p.c. and then incubated for 24 h. The inner cell masses continue to grow in culture and develop through a series of stages with increasing complexity of internal organization. By day 1 all of the cultured ICMs have an outer layer of endoderm, and by day 3 some of them have two distinct kinds of inside cells; a columnar epithelial layer and a thin hemisphere of elongated cells. Later, mesodermal cells appear to delaminate from a limited region of the columnar layer, close to where it forms a junction with the thinner cells. By day 5, about 25% of the cultured ICMs have a striking resemblance to normal 7.5-day p.c. C3H embryos, with embryonic ectoderm, extra-embryonic ectoderm and chorion, embryonic and extra-embryonic mesoderm, and visceral endoderm. When mechanically disrupted and grown as attached clumps of cells in a tissue dish, these embryo-like structures give rise to trophoblast-like giant cells. These results suggest that the inner cell mass of 4.5-day p.c. blastocysts contains cells which can give rise to trophoblast derivates in culture.

Animals↗

PubMed1991

Differential expression of two cadherins in Xenopus laevis.

Using a cadherin fraction from Xenopus tissue culture cells as an immunogen, two monoclonal antibodies were obtained that allowed the characterization of two distinct cadherins in the Xenopus embryo. The two cadherins differ in molecular weight, in their time of appearance during development and in their spatial pattern of expression. One of the antigens was identified as E-cadherin. It appears in the embryonic ectoderm during gastrulation when epidermal differentiation commences and it disappears from the neural plate area upon neural induction. The second antigen could not be allocated to any of the known cadherin subtypes and was termed U-cadherin. It is present in the egg and becomes deposited in newly formed inner cell membranes during cleavage, the outer apical membranes of the embryo remaining devoid of the cadherin throughout development. U-cadherin is found on membranes of all cells up to the late neurula stages. A conspicuous polarized expression of the antigen on the membranes of individual inner cells suggests its participation in the segregation of cell layers and organ anlagen. These findings are discussed in the context of current hypotheses on the role of cadherins in establishing the spatial structure of the embryo.

Animals↗

PubMedDate not supplied

Origin of the vertebrate inner ear: evolution and induction of the otic placode.

The vertebrate inner ear forms a highly complex sensory structure responsible for the detection of sound and balance. Some new aspects on the evolutionary and developmental origin of the inner ear are summarised here. Recent molecular data have challenged the longstanding view that special sense organs such as the inner ear have evolved with the appearance of vertebrates. In addition, it has remained unclear whether the ear originally arose through a modification of the amphibian mechanosensory lateral line system or whether both evolved independently. A comparison of the developmental mechanisms giving rise to both sensory systems in different species should help to clarify some of these controversies. During embryonic development, the inner ear arises from a simple epithelium adjacent to the hindbrain, the otic placode, that is specified through inductive interactions with surrounding tissues. This review summarises the embryological evidence showing that the induction of the otic placode is a multistep process which requires sequential interaction of different tissues with the future otic ectoderm and the recent progress that has been made to identify some of the molecular players involved. Finally, the hypothesis is discussed that induction of all sensory placodes initially shares a common molecular pathway, which may have been responsible to generate an 'ancestral placode' during evolution.

Animals↗

PubMed1984

Formation of the test in the swimming larva of Ciona intestinalis: an ultrastructural study.

The test of the Ciona intestinalis larva, before hatching, presents a single outer cuticular layer, C1. Ultrastructural observations of swimming larvae, kept in culture at 18 degrees C, show that the test is enriched by a second inner cuticular layer C2. The C2 layer begins to form in the larva immediately after hatching (about 1 h) and is a process caused by the activity of the cells of the ectodermal layer. During this phase of larval development these cells assume the typical ultrastructure of cells with secretory activity, presenting a well developed r.e.r. and a Golgi in the form of dictyosomes in active synthesis phase in the apical zone of their cytoplasm. The formation of C2 layer is complete in the larva 3 h after hatching and in this period it can be seen parallel to, and a short distance from, the plasmalemma of the ectodermal cells. In the cephalenteron region the C2 layer progressively rises towards the C1 layer and, in the larva 8 h after hatching, these two layers are very close together, about 1000 A apart. In contrast, the C2 layer in the tail remains close to the plasmalemma of the ectodermal cells and can only be detected by ultrastructural observations.

Animals↗

PubMed1993

Spatio-temporal distribution of acidic and basic FGF indicates a role for FGF in rat lens morphogenesis.

As part of an investigation into the role of FGF in lens development, we have studied the distribution of both aFGF and bFGF during eye morphogenesis from embryonic days 10 to 18 (E10-E18) in the rat. For aFGF, reactivity was found only in ectoderm at E10, prior to contact between the optic vesicle and presumptive lens ectoderm. During lens placode formation (E11) there was a transient, diffuse reactivity for aFGF in anterior optic vesicle cells directly apposed to the labelled ectoderm of the lens placode. At E12 the diffuse reactivity of the lens placode had changed to a discrete localisation along the basolateral surfaces of differentiating cells in the lens pit. Similar reactivity was associated with neuroblasts along the inner margin of the optic cup. At the early lens vesicle stage (E13) the baso-lateral aFGF-like reactivity associated with elongating lens cells was more intense and extensive. From the late lens vesicle stage (E14) to E18, reactivity in the lens was increasingly restricted to the equatorial regions which incorporate the germinative and transitional zones. From E16 to E18, aFGF-like reactivity in the retina was predominantly localised in the peripheral regions corresponding to the developing ciliary body and iris and in the central retina associated with ganglion cell axons. For bFGF, weak reactivity was detectable as early as E13 in the developing lens capsule and increased in intensity during lens development with the posterior capsule reacting more intensely than the anterior capsule. Retinal bFGF-like reactivity was first detected at E14, associated with differentiating ganglion cells in the central retina. From E16 to E18 the retinal ganglion cells showed increasing reactivity and the pattern of reactivity followed the centro-peripheral pattern of retinal development. Thus reactivity for aFGF is first detected in presumptive lens ectoderm and subsequently in optic vesicle cells which are closely associated with lens ectoderm. This raises the possibility that aFGF may be involved in inductive interactions between presumptive lens ectoderm and optic vesicle. Furthermore the localisation patterns established for both aFGF and bFGF during lens and retina morphogenesis suggest an important role for FGF in regulating their morphogenesis and growth.

Animals↗