151
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Achieving bilateral symmetry during vertebrate limb development. Semin Cell Dev Biol 2008; 20:479-84. [PMID: 19027866 DOI: 10.1016/j.semcdb.2008.10.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 10/24/2008] [Indexed: 02/06/2023]
Abstract
While the various internal organs of vertebrates display many obvious left-right asymmetries in their location and/or morphology, external features exhibit a high degree of bilateral symmetry. How this external bilateral symmetry is established during development is largely unknown. In this review, we explore several mechanisms, in place during development, that regulate the final size of the limb. These mechanisms rely on the presence of positive signaling feedback loops during limb bud growth. Through the activity of these signaling loops and their eventual breakdown when the limb bud has reached a certain size, bilateral symmetry can be achieved.
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152
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Affiliation(s)
- Saara M. Rawn
- Department of Comparative Biology & Experimental Medicine, Faculty of Veterinary Medicine, and the Graduate Program in Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada; ,
| | - James C. Cross
- Department of Comparative Biology & Experimental Medicine, Faculty of Veterinary Medicine, and the Graduate Program in Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada; ,
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153
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Gelineau-van Waes J, Heller S, Bauer LK, Wilberding J, Maddox JR, Aleman F, Rosenquist TH, Finnell RH. Embryonic development in the reduced folate carrier knockout mouse is modulated by maternal folate supplementation. ACTA ACUST UNITED AC 2008; 82:494-507. [PMID: 18383508 DOI: 10.1002/bdra.20453] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The reduced folate carrier (RFC1) is a ubiquitously expressed integral membrane protein that mediates delivery of 5-methyltetrahydrofolate into mammalian cells. In this study, embryonic/fetal development is characterized in an RFC1 knockout mouse model in which pregnant dams receive different levels of folate supplementation. METHODS RFC1(+/-) males were mated to RFC1(+/-) females, and pregnant dams were treated with vehicle (control) or folic acid (25 or 50 mg/kg) by daily subcutaneous injection (0.1 mL/10 g bwt), beginning on E0.5 and continuing throughout gestation until the time of sacrifice. RESULTS Without maternal folate supplementation, RFC1 nullizygous embryos die shortly postimplantation. Supplementation of pregnant dams with 25 mg/kg/day folic acid prolongs survival of mutant embryos until E9.5-E10.5, but they are developmentally delayed relative to wild-type littermates, display a marked absence of erythropoiesis, severe neural tube and limb bud defects, and failure of chorioallantoic fusion. Fgfr2 protein levels are significantly reduced or absent in the extraembryonic membranes of RFC1 nullizygous embryos. Maternal folate supplementation with 50 mg/kg/day results in survival of 22% of RFC1 mutants to E18.5, but they develop with multiple malformations of the eyelids, lungs, heart, and skin. CONCLUSIONS High doses of daily maternal folate supplementation during embryonic/fetal development are necessary for early postimplantation embryonic viability of RFC1 nullizygous embryos, and play a critical role in chorioallantoic fusion, erythropoiesis, and proper development of the neural tube, limbs, lungs, heart, and skin.
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Affiliation(s)
- Janee Gelineau-van Waes
- Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, Omaha, Nebraska 68198-5455, USA.
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154
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Chiang YJ, Hsiao SJ, Yver D, Cushman SW, Tessarollo L, Smith S, Hodes RJ. Tankyrase 1 and tankyrase 2 are essential but redundant for mouse embryonic development. PLoS One 2008; 3:e2639. [PMID: 18612384 PMCID: PMC2441437 DOI: 10.1371/journal.pone.0002639] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 06/09/2008] [Indexed: 11/28/2022] Open
Abstract
Tankyrases are proteins with poly(ADP-ribose) polymerase activity. Human tankyrases post-translationally modify multiple proteins involved in processes including maintenance of telomere length, sister telomere association, and trafficking of glut4-containing vesicles. To date, however, little is known about in vivo functions for tankyrases. We recently reported that body size was significantly reduced in mice deficient for tankyrase 2, but that these mice otherwise appeared developmentally normal. In the present study, we report generation of tankyrase 1-deficient and tankyrase 1 and 2 double-deficient mice, and use of these mutant strains to systematically assess candidate functions of tankyrase 1 and tankyrase 2 in vivo. No defects were observed in development, telomere length maintenance, or cell cycle regulation in tankyrase 1 or tankyrase 2 knockout mice. In contrast to viability and normal development of mice singly deficient in either tankyrase, deficiency in both tankyrase 1 and tankyrase 2 results in embryonic lethality by day 10, indicating that there is substantial redundancy between tankyrase 1 and tankyrase 2, but that tankyrase function is essential for embryonic development.
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Affiliation(s)
- Y Jeffrey Chiang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
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155
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Limb bud and flank mesoderm have distinct "physical phenotypes" that may contribute to limb budding. Dev Biol 2008; 321:319-30. [PMID: 18601915 DOI: 10.1016/j.ydbio.2008.06.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 05/09/2008] [Accepted: 06/04/2008] [Indexed: 02/03/2023]
Abstract
Limb bud outgrowth in chicken embryos is initiated during the third day of development by Fibroblast Growth Factor 8 (FGF8) produced by the newly formed apical ectodermal ridge (AER). One of the earliest effects of this induction is a change in the properties of the limb field mesoderm leading to bulging of the limb buds from the body wall. Heintzelman et al. [Heintzelman, K.F., Phillips, H.M., Davis, G.S., 1978. Liquid-tissue behavior and differential cohesiveness during chick limb budding. J. Embryol. Exp. Morphol. 47, 1-15.] suggested that budding of the limbs is caused by a higher liquid-like cohesivity of limb bud tissue compared with flank. We sought additional evidence relevant to this hypothesis by performing direct measurements of the effective surface tension, a measure of relative tissue cohesivity, of 4-day embryonic chicken wing and leg bud mesenchymal tissue, and adjacent flank mesoderm. As predicted, the two types of limb tissues were 1.5- to 2-fold more cohesive than the flank tissue. These differences paralleled cell number and volume density differences: 4-day limb buds had 2- to 2.5-fold as many cells per unit area of tissue as surrounding flank, a difference also seen at 3 days, when limb budding begins. Exposure of flank tissue to exogenous FGF8 for 24 h increased its cell number and raised its cohesivity to limb-like values. Four-day flank tissue exhibited a novel and unique active rebound response to compression, which was suppressed by the drug latrunculin and therefore dependent on an intact actin cytoskeleton. Correspondingly, flank at this stage expressed high levels of alpha-smooth muscle actin (SMA) mRNA and protein and a dense network of microfilaments. Treatment of flank with FGF8 eliminated the rebound response. We term material properties of tissues, such as cohesivity and mechanical excitability, the "physical phenotype", and propose that changes thereof are driving forces of morphogenesis. Our results indicate that two independent aspects of the physical phenotype of flank mesoderm can be converted to a limb-like state in response to treatment with FGF8. The higher tissue cohesivity induced by this effect will cause the incipient limb bud to phase separate from the surrounding flank, while the active mechanical response of the flank could help ensure that the limb bud bulges out from, rather than becoming engulfed by, this less cohesive tissue.
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156
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Lu P, Ewald AJ, Martin GR, Werb Z. Genetic mosaic analysis reveals FGF receptor 2 function in terminal end buds during mammary gland branching morphogenesis. Dev Biol 2008; 321:77-87. [PMID: 18585375 DOI: 10.1016/j.ydbio.2008.06.005] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2008] [Revised: 05/30/2008] [Accepted: 06/02/2008] [Indexed: 01/05/2023]
Abstract
FGF signaling is associated with breast cancer and is required for mammary placode formation in the mouse. In this study, we employed a genetic mosaic analysis based on Cre-mediated recombination to investigate FGF receptor 2 (Fgfr2) function in the postnatal mammary gland. Mosaic inactivation of Fgfr2 by the MMTV-Cre transgene enabled us to compare the behavior of Fgfr2 null and Fgfr2 heterozygous cells in the same gland. Fgfr2 null cells were at a competitive disadvantage to their Fgfr2 heterozygous neighbors in the highly proliferative terminal end buds (TEBs) at the invasion front, owing to a negative effect of loss of Fgfr2 function on cell proliferation. However, Fgfr2 null cells were tolerated in mature ducts. In these genetic mosaic mammary glands, the epithelial network is apparently built by TEBs that over time are composed of a progressively larger proportion of Fgfr2-positive cells. However, subsequently, most cells lose Fgfr2 function, presumably due to additional rounds of Cre-mediated recombination. Using an independent strategy to create mosaic mammary glands, which employed an adenovirus-Cre that acts only once, we confirmed that Fgfr2 null cells were out-competed by neighboring Fgfr2 heterozygous cells. Together, our data demonstrate that Fgfr2 functions in the proliferating and invading TEBs, but it is not required in the mature ducts of the pubertal mammary gland.
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Affiliation(s)
- Pengfei Lu
- Department of Anatomy and Program in Developmental Biology, University of California at San Francisco, San Francisco, CA 94143-0452, USA
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157
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Konishi M, Nakamura H, Miwa H, Chambon P, Ornitz DM, Itoh N. Role of Fgf receptor 2c in adipocyte hypertrophy in mesenteric white adipose tissue. Mol Cell Endocrinol 2008; 287:13-9. [PMID: 18396371 DOI: 10.1016/j.mce.2008.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 12/19/2007] [Accepted: 02/14/2008] [Indexed: 10/22/2022]
Abstract
Fgf receptor 2c (Fgfr2c) was expressed in mature adipocytes of mouse white adipose tissue (WAT). To examine the role of Fgfr2c in mature adipocytes, we generated adipocyte-specific Fgfr2 knockout (Fgfr2 CKO) mice. The hypertrophy impairment of adipocytes in the mesenteric WAT but not in the subcutaneous WAT and decreased plasma free fatty acid (FFA) levels were observed in Fgfr2 CKO mice. Although the expression of genes involved in adipocyte differentiation and lipid metabolism in the mesenteric WAT was essentially unchanged, the expression of uncoupling protein 2 potentially involved in energy dissipation was significantly increased. Among potential Fgf ligands for Fgfr2c, Fgf9 was preferentially expressed in the mesenteric WAT. The present findings indicate that Fgfr2c potentially activated by Fgf9 plays a role in the adipocyte hypertrophy in the mesenteric WAT and FFA metabolism and/or energy dissipation in the mesenteric WAT might be involved in the hypertrophy impairment.
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Affiliation(s)
- Morichika Konishi
- Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Yoshida-Shimoadachi, Sakyo, Kyoto 606-8501, Japan
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158
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Cotton LM, O'Bryan MK, Hinton BT. Cellular signaling by fibroblast growth factors (FGFs) and their receptors (FGFRs) in male reproduction. Endocr Rev 2008; 29:193-216. [PMID: 18216218 PMCID: PMC2528845 DOI: 10.1210/er.2007-0028] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 11/29/2007] [Indexed: 12/25/2022]
Abstract
The major function of the reproductive system is to ensure the survival of the species by passing on hereditary traits from one generation to the next. This is accomplished through the production of gametes and the generation of hormones that function in the maturation and regulation of the reproductive system. It is well established that normal development and function of the male reproductive system is mediated by endocrine and paracrine signaling pathways. Fibroblast growth factors (FGFs), their receptors (FGFRs), and signaling cascades have been implicated in a diverse range of cellular processes including: proliferation, apoptosis, cell survival, chemotaxis, cell adhesion, motility, and differentiation. The maintenance and regulation of correct FGF signaling is evident from human and mouse genetic studies which demonstrate that mutations leading to disruption of FGF signaling cause a variety of developmental disorders including dominant skeletal diseases, infertility, and cancer. Over the course of this review, we will provide evidence for differential expression of FGFs/FGFRs in the testis, male germ cells, the epididymis, the seminal vesicle, and the prostate. We will show that this signaling cascade has an important role in sperm development and maturation. Furthermore, we will demonstrate that FGF/FGFR signaling is essential for normal epididymal function and prostate development. To this end, we will provide evidence for the involvement of the FGF signaling system in the regulation and maintenance of the male reproductive system.
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Affiliation(s)
- Leanne M Cotton
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA
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159
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Zhao H, Yang T, Madakashira BP, Thiels CA, Bechtle CA, Garcia CM, Zhang H, Yu K, Ornitz DM, Beebe DC, Robinson ML. Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation. Dev Biol 2008; 318:276-88. [PMID: 18455718 DOI: 10.1016/j.ydbio.2008.03.028] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 03/14/2008] [Accepted: 03/17/2008] [Indexed: 11/19/2022]
Abstract
The vertebrate lens provides an excellent model to study the mechanisms that regulate terminal differentiation. Although fibroblast growth factors (FGFs) are thought to be important for lens cell differentiation, it is unclear which FGF receptors mediate these processes during different stages of lens development. Deletion of three FGF receptors (Fgfr1-3) early in lens development demonstrated that expression of only a single allele of Fgfr2 or Fgfr3 was sufficient for grossly normal lens development, while mice possessing only a single Fgfr1 allele developed cataracts and microphthalmia. Profound defects were observed in lenses lacking all three Fgfrs. These included lack of fiber cell elongation, abnormal proliferation in prospective lens fiber cells, reduced expression of the cell cycle inhibitors p27(kip1) and p57(kip2), increased apoptosis and aberrant or reduced expression of Prox1, Pax6, c-Maf, E-cadherin and alpha-, beta- and gamma-crystallins. Therefore, while signaling by FGF receptors is essential for lens fiber differentiation, different FGF receptors function redundantly.
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MESH Headings
- Animals
- Cell Differentiation
- Cell Enlargement
- Cyclin-Dependent Kinase Inhibitor p27/metabolism
- Cyclin-Dependent Kinase Inhibitor p57/metabolism
- Eye Abnormalities/embryology
- Fibroblast Growth Factors/metabolism
- Gene Targeting
- Homeodomain Proteins/metabolism
- Lens, Crystalline/cytology
- Lens, Crystalline/embryology
- Mice
- Mutation
- Proto-Oncogene Proteins c-maf/metabolism
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/metabolism
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/metabolism
- Signal Transduction
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Haotian Zhao
- Graduate Program in Molecular, Cellular and Developmental Biology, College of Biological Sciences, The Ohio State University, Columbus, OH 43210, USA
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160
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Bagheri-Fam S, Sim H, Bernard P, Jayakody I, Taketo MM, Scherer G, Harley VR. Loss of Fgfr2 leads to partial XY sex reversal. Dev Biol 2008; 314:71-83. [DOI: 10.1016/j.ydbio.2007.11.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 11/05/2007] [Accepted: 11/08/2007] [Indexed: 11/25/2022]
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161
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Paul EL, Badal R, Thompson DS, Magnan DR, Soucy FM, Khan IM, Haughton RA, King TR. The mouse frizzy mutation (fr) maps between D7Csu5 and D7Mit165. Exp Dermatol 2007; 17:640-4. [PMID: 18177347 DOI: 10.1111/j.1600-0625.2007.00676.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously shown that the rat fuzzy and Charles River 'hairless' mutations are defects in the same gene on rat Chr 1, and are likely orthologues of the frizzy mutation (fr) on mouse Chr 7. To test the hypothesis that these variants could result from defects in Fgfr2, we crossed fr/fr mice (from the inbred FS/EiJ strain) with mice that carry a recessive lethal mutation in Fgfr2. Mice inheriting both mutations were phenotypically normal, indicating that fr is not an allele of Fgfr2. To genetically map fr, we crossed these hybrid mice, or F(1) mice made by crossing FS/EiJ with the wild-type C57BL/6J or BALB/cBy strains, back to the FS/EiJ strain. The resulting 546 backcross progeny were typed for linked markers to position fr centromeric of Fgfr2, between D7Csu5 and D7Mit165; an interval that contains only 2.7 Mb and fewer than 70 genes. Further characterization of regional recombinants for sequence-level polymorphisms should allow sufficient refinement of fr's location to facilitate an eventual molecular assignment for this classical mutation.
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Affiliation(s)
- Emily L Paul
- Biomolecular Sciences, Central Connecticut State University, New Britain, Connecticut, USA
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162
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Britto JA. Advances in the molecular pathogenesis of craniofacial conditions. Oral Maxillofac Surg Clin North Am 2007; 16:567-86. [PMID: 18088755 DOI: 10.1016/j.coms.2004.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The impact that the understanding of fibroblast growth factor receptor (FGFR) biology and its relevance to the pathogenesis of the craniosynostoses has made cannot be underestimated. As the genetic and molecular pathology of other conditions become increasingly understood, there is much hope that robust and relevant animal models of these conditions may be generated. From these models-and in conjunction with laboratory studies in vitro-comes a real hope of improved therapeutic strategies. The future lies in increased cooperation between clinicians working in high-volume centers and basic scientists. This article decribes the results of a decade of research in which the molecular pathology of the craniosynostoses was unravelled. The understanding of the importance of FGFR mutations to the genetic etiology of craniosynostosis opened up novel studies in developmental biology in various tissues. Such studies describe the functional effects of FGFR mutations. Investigations of FGFR expression in human craniofacial development have related functional molecular studies to human craniosynostosis syndromes, which provides a link between the gene mutation and the affected child.
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Affiliation(s)
- Jonathan A Britto
- Craniofacial Centre, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London WC1N3JH, UK
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163
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Abstract
While urodele amphibians (newts and salamanders) can regenerate limbs as adults, other tetrapods (reptiles, birds and mammals) cannot and just undergo wound healing. In adult mammals such as mice and humans, the wound heals and a scar is formed after injury, while wound healing is completed without scarring in an embryonic mouse. Completion of regeneration and wound healing takes a long time in regenerative and non-regenerative limbs, respectively. However, it is the early steps that are critical for determining the extent of regenerative response after limb amputation, ranging from wound healing with scar formation, scar-free wound healing, hypomorphic limb regeneration to complete limb regeneration. In addition to the accumulation of information on gene expression during limb regeneration, functional analysis of signaling molecules has recently shown important roles of fibroblast growth factor (FGF), Wnt/beta-catenin and bone morphogenic protein (BMP)/Msx signaling. Here, the routine steps of wound healing/limb regeneration and signaling molecules specifically involved in limb regeneration are summarized. Regeneration of embryonic mouse digit tips and anuran amphibian (Xenopus) limbs shows intermediate regenerative responses between the two extremes, those of adult mammals (least regenerative) and urodele amphibians (more regenerative), providing a range of models to study the various abilities of limbs to regenerate.
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Affiliation(s)
- Hitoshi Yokoyama
- Howard Hughes Medical Institute, Department of Pharmacology, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA.
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164
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Shams I, Rohmann E, Eswarakumar VP, Lew ED, Yuzawa S, Wollnik B, Schlessinger J, Lax I. Lacrimo-auriculo-dento-digital syndrome is caused by reduced activity of the fibroblast growth factor 10 (FGF10)-FGF receptor 2 signaling pathway. Mol Cell Biol 2007; 27:6903-12. [PMID: 17682060 PMCID: PMC2099236 DOI: 10.1128/mcb.00544-07] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Lacrimo-auriculo-dento-digital (LADD) syndrome is characterized by abnormalities in lacrimal and salivary glands, in teeth, and in the distal limbs. Genetic studies have implicated heterozygous mutations in fibroblast growth factor 10 (FGF10) and in FGF receptor 2 (FGFR2) in LADD syndrome. However, it is not clear whether LADD syndrome mutations (LADD mutations) are gain- or loss-of-function mutations. In order to reveal the molecular mechanism underlying LADD syndrome, we have compared the biological properties of FGF10 LADD and FGFR2 LADD mutants to the activities of their normal counterparts. These experiments show that the biological activities of three different FGF10 LADD mutants are severely impaired by different mechanisms. Moreover, haploinsufficiency caused by defective FGF10 mutants leads to LADD syndrome. We also demonstrate that the tyrosine kinase activities of FGFR2 LADD mutants expressed in transfected cells are strongly compromised. Since tyrosine kinase activity is stimulated by ligand-induced receptor dimerization, FGFR2 LADD mutants may also exert a dominant inhibitory effect on signaling via wild-type FGFR2 expressed in the same cell. These experiments underscore the importance of signal strength in mediating biological responses and that relatively small changes in receptor signaling may influence the outcome of developmental processes in cells or organs that do not possess redundant signaling pathway.
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Affiliation(s)
- Imad Shams
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
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165
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Zakany J, Duboule D. The role of Hox genes during vertebrate limb development. Curr Opin Genet Dev 2007; 17:359-66. [PMID: 17644373 DOI: 10.1016/j.gde.2007.05.011] [Citation(s) in RCA: 290] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 05/22/2007] [Accepted: 05/31/2007] [Indexed: 01/11/2023]
Abstract
The potential role of Hox genes during vertebrate limb development was brought into focus by gene expression analyses in mice (P Dolle, JC Izpisua-Belmonte, H Falkenstein, A Renucci, D Duboule, Nature 1989, 342:767-772), at a time when limb growth and patterning were thought to depend upon two distinct and rather independent systems of coordinates; one for the anterior-to-posterior axis and the other for the proximal-to-distal axis (see D Duboule, P Dolle, EMBO J 1989, 8:1497-1505). Over the past years, the function and regulation of these genes have been addressed using both gain-of-function and loss-of-function approaches in chick and mice. The use of multiple mutations either in cis-configuration in trans-configuration or in cis/trans configurations, has confirmed that Hox genes are essential for proper limb development, where they participate in both the growth and organization of the structures. Even though their molecular mechanisms of action remain somewhat elusive, the results of these extensive genetic analyses confirm that, during the development of the limbs, the various axes cannot be considered in isolation from each other and that a more holistic view of limb development should prevail over a simple cartesian, chess grid-like approach of these complex structures. With this in mind, the functional input of Hox genes during limb growth and development can now be re-assessed.
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Affiliation(s)
- Jozsef Zakany
- National Research Centre Frontiers in Genetics, Department of Zoology and Animal Biology, University of Geneva, Sciences III, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
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166
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Woei Ng K, Speicher T, Dombrowski C, Helledie T, Haupt LM, Nurcombe V, Cool SM. Osteogenic differentiation of murine embryonic stem cells is mediated by fibroblast growth factor receptors. Stem Cells Dev 2007; 16:305-18. [PMID: 17521241 DOI: 10.1089/scd.2006.0044] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The mechanisms involved in the control of embryonic stem (ES) cell differentiation are yet to be fully elucidated. However, it has become clear that the family of fibroblast growth factors (FGFs) are centrally involved. In this study we examined the role of the FGF receptors (FGFRs 1-4) during osteogenesis in murine ES cells. Single cells were obtained after the formation of embryoid bodies, cultured on gelatin-coated plates, and coaxed to differentiate along the osteogenic lineage. Upregulation of genes was analyzed at both the transcript and protein levels using gene array, relative-quantitative PCR (RQ-PCR), and Western blotting. Deposition of a mineralized matrix was evaluated with Alizarin Red staining. An FGFR1-specific antibody was generated and used to block FGFR1 activity in mES cells during osteogenic differentiation. Upon induction of osteogenic differentiation in mES cells, all four FGFRs were clearly upregulated at both the transcript and protein levels with a number of genes known to be involved in osteogenic differentiation including bone morphogenetic proteins (BMPs), collagen I, and Runx2. Cells were also capable of depositing a mineralized matrix, confirming the commitment of these cells to the osteogenic lineage. When FGFR1 activity was blocked, a reduction in cell proliferation and a coincident upregulation of Runx2 with enhanced mineralization of cultures was observed. These results indicate that FGFRs play critical roles in cell recruitment and differentiation during the process of osteogenesis in mES cells. In particular, the data indicate that FGFR1 plays a pivotal role in osteoblast lineage determination.
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Affiliation(s)
- Kee Woei Ng
- Stem Cell and Tissue Repair Laboratory, Institute of Molecular and Cell Biology, Proteos, Singapore 138673
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167
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Hendrikse JL, Parsons TE, Hallgrímsson B. Evolvability as the proper focus of evolutionary developmental biology. Evol Dev 2007; 9:393-401. [PMID: 17651363 DOI: 10.1111/j.1525-142x.2007.00176.x] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Research conducted under the label of evolutionary developmental biology has tended to revolve around a few central issues such as modularity, integration, and canalization. Yet, as the field has grown, it has become increasingly difficult to define in terms of its central question and relation to broader evolutionary concerns. We argue that these central issues of evo-devo gain their currency from connections to a central question that defines the field, and we propose that this central question is about the nature of evolvability. However, not all research currently carried out under the label of "evo-devo" speaks to this focal concern. The aim of this article is therefore to argue for a precise formulation of evolutionary developmental biology's core question.
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Affiliation(s)
- Jesse Love Hendrikse
- Department of Philosophy, University of Calgary 2500 University Dr. NW Calgary, AB, Canada T2N 1N4
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168
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Inman KE, Downs KM. The murine allantois: emerging paradigms in development of the mammalian umbilical cord and its relation to the fetus. Genesis 2007; 45:237-58. [PMID: 17440924 DOI: 10.1002/dvg.20281] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The fertilized egg of the mammal gives rise to the embryo and its extraembryonic structures, all of which develop in intimate relation with each other. Yet, whilst the past several decades have witnessed a vast number of studies on the embryonic component of the conceptus, study of the extraembryonic tissues and their relation to the fetus have been largely ignored. The allantois, precursor tissue of the mature umbilical cord, is a universal feature of all placental mammals that establishes the vital vascular bridge between the fetus and its mother. The allantois differentiates into the umbilical blood vessels, which become secured onto the chorionic component of the placenta at one end and onto the fetus at the other. In this way, fetal blood is channeled through the umbilical cord for exchange with the mother. Despite the importance of this vascular bridge, little is known about how it is made. The aim of this review is to address current understanding of the biology of the allantois in the mouse and genetic control of its features and functions, and to highlight new paradigms concerning the developmental relationship between the fetus and its umbilical cord.
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Affiliation(s)
- Kimberly E Inman
- Department of Anatomy, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin 53706, USA
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169
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Artoni L, Moura C, Barbosa Jr E, Campos D, Pereira F, Papa P. Fator de crescimento fibroblástico básico e seus receptores em relação à atividade proliferativa na placenta bubalina em diferentes fases da gestação. ARQ BRAS MED VET ZOO 2007. [DOI: 10.1590/s0102-09352007000300009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Estudou-se a distribuição espaço-temporal do fator de crescimento fibroblástico básico (bFGF), do receptor 1 do fator de crescimento fibroblástico (FGFR1) e do receptor 2 do fator de crescimento fibroblástico (FGFR2) na placenta bubalina, correlacionando-a à proliferação celular. Para a detecção do bFGF, FGFR1, FGFR2 e antígeno Ki-67, colheram-se 12 placentas de búfalas nos terços inicial, médio e final da gestação, em abatedouros, e realizaram-se testes de imunoistoquímica. Detectou-se e avaliou-se a expressão do bFGF, do FGFR1, do FGFR2 e do antígeno Ki-67 ao longo da gestação. No compartimento fetal da placenta, observaram-se correlações positivas entre a expressão do bFGF e Ki-67, entre FGFR1 e Ki-67 e entre FGFR2 com Ki-67 (r=0,313, 0,358 e 0,384, respectivamente). No epitélio e estroma maternos observaram-se altas correlações entre FGFR1 e Ki-67 (r=0,739 e r=0,511, respectivamente). Os resultados sugerem envolvimento do bFGF, FGFR1 e FGFR2 na proliferação do trofoblasto enquanto no compartimento materno da placenta bubalina apenas o FGFR1 atuaria como modulador dessa atividade.
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Affiliation(s)
- L.P. Artoni
- Faculdade de Medicina Veterinária e Zootecnia
| | | | | | - D.B. Campos
- Faculdade de Medicina Veterinária e Zootecnia
| | | | - P.C. Papa
- Faculdade de Medicina Veterinária e Zootecnia
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170
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Zakany J, Zacchetti G, Duboule D. Interactions between HOXD and Gli3 genes control the limb apical ectodermal ridge via Fgf10. Dev Biol 2007; 306:883-93. [PMID: 17467687 DOI: 10.1016/j.ydbio.2007.03.517] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 03/05/2007] [Accepted: 03/26/2007] [Indexed: 10/23/2022]
Abstract
The development of the vertebrate limb is dependent upon two signaling centers, the apical ectodermal ridge (AER), which provides the underlying mesenchyme with essential growth factors, and the zone of polarizing activity (ZPA), the source of the Sonic hedgehog (SHH) product. Recent work involving gain and loss of function of Hox genes has emphasized their impact both on AER maintenance and Shh transcriptional activation. Here, we describe antagonistic interactions between posterior Hoxd genes and Gli3, suggesting that the latter product protects the AER from the deleterious effect of the formers, and we present evidence that Fgf10 is the mediator of HOX-dependent AER expansion. Furthermore, the striking similarity between some of the hereby observed Hox/Gli3-dependent morphogenetic defects and those displayed by fetuses with severely altered retinoic acid metabolism suggests a tight connection between these various pathways. The nature of these potential interactions is discussed in the context of proximal-distal growth and patterning.
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Affiliation(s)
- Jozsef Zakany
- Department of Zoology and Animal Biology and National Research Centre/Frontiers in Genetics, University of Geneva, Sciences III, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
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171
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Yokoyama H, Ogino H, Stoick-Cooper CL, Grainger RM, Moon RT. Wnt/beta-catenin signaling has an essential role in the initiation of limb regeneration. Dev Biol 2007; 306:170-8. [PMID: 17442299 PMCID: PMC2703180 DOI: 10.1016/j.ydbio.2007.03.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 03/09/2007] [Accepted: 03/09/2007] [Indexed: 10/23/2022]
Abstract
Anuran (frog) tadpoles and urodeles (newts and salamanders) are the only vertebrates capable of fully regenerating amputated limbs. During the early stages of regeneration these amphibians form a "blastema", a group of mesenchymal progenitor cells that specifically directs the regrowth of the limb. We report that wnt-3a is expressed in the apical epithelium of regenerating Xenopus laevis limb buds, at the appropriate time and place to play a role during blastema formation. To test whether Wnt/beta-catenin signaling is required for limb regeneration, we created transgenic X. laevis tadpoles that express Dickkopf-1 (Dkk1), a specific inhibitor of Wnt/beta-catenin signaling, under the control of a heat-shock promoter. Heat-shock immediately before limb amputation or during early blastema formation blocked limb regeneration but did not affect the development of contralateral, un-amputated limb buds. When the transgenic tadpoles were heat-shocked following the formation of a blastema, however, they retained the ability to regenerate partial hindlimb structures. Furthermore, heat-shock induced Dkk1 blocked fgf-8 but not fgf-10 expression in the blastema. We conclude that Wnt/beta-catenin signaling has an essential role during the early stages of limb regeneration, but is not absolutely required after blastema formation.
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Affiliation(s)
- Hitoshi Yokoyama
- Howard Hughes Medical Institute, Department of Pharmacology, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Hajime Ogino
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Cristi L. Stoick-Cooper
- Howard Hughes Medical Institute, Department of Pharmacology, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Rob M. Grainger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Randall T. Moon
- Howard Hughes Medical Institute, Department of Pharmacology, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
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172
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Beare AHM, Metcalfe AD, Ferguson MWJ. Location of injury influences the mechanisms of both regeneration and repair within the MRL/MpJ mouse. J Anat 2007; 209:547-59. [PMID: 17005026 PMCID: PMC2100365 DOI: 10.1111/j.1469-7580.2006.00641.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The adult MRL/MpJ mouse regenerates all differentiated structures after through-and-through ear punch wounding in a scar-free process. We investigated whether this regenerative capacity was also shown by skin wounds. Dorsal skin wounds were created, harvested and archived from the same animals (MRL/MpJ and C57BL/6 mice) that received through-and-through ear punch wounds. Re-epithelialization was complete in dorsal wounds in both strains by day 5 and extensive granulation tissue was present by day 14 post-wounding. By day 21, wounds from both strains contained dense amounts of collagen that healed with a scar. The average wound area, as well as alpha-smooth muscle actin expression and macrophage influx were investigated during dorsal skin wound healing and did not significantly differ between strains. Thus, MRL/MpJ mice regenerate ear wounds in a scar-free manner, but heal dorsal skin wounds by simple repair with scar formation. A significant conclusion can be drawn from these data; mechanisms of regeneration and repair can occur within the same animal, potentially utilizing similar molecules and signalling pathways that subtly diverge dependent upon the microenvironment of the injury.
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Affiliation(s)
- Alice H M Beare
- UK Centre for Tissue Engineering, Faculty of Life Sciences, University of Manchester, Manchester, UK
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173
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Papadaki C, Alexiou M, Cecena G, Verykokakis M, Bilitou A, Cross JC, Oshima RG, Mavrothalassitis G. Transcriptional repressor erf determines extraembryonic ectoderm differentiation. Mol Cell Biol 2007; 27:5201-13. [PMID: 17502352 PMCID: PMC1951951 DOI: 10.1128/mcb.02237-06] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Extraembryonic ectoderm differentiation and chorioallantoic attachment are fibroblast growth factor (FGF)- and transforming growth factor beta-regulated processes that are the first steps in the development of the placenta labyrinth and the establishment of the fetal-maternal circulation in the developing embryo. Only a small number of genes have been demonstrated to be important in trophoblast stem cell differentiation. Erf is a ubiquitously expressed Erk-regulated, ets domain transcriptional repressor expressed throughout embryonic development and adulthood. However, in the developing placenta, after 7.5 days postcoitum (dpc) its expression is restricted to the extraembryonic ectoderm, and its expression is restricted after 9.5 dpc in a subpopulation of labyrinth cells. Homozygous deletion of Erf in mice leads to a block of chorionic cell differentiation before chorioallantoic attachment, resulting in a persisting chorion layer, a persisting ectoplacental cone cavity, failure of chorioallantoic attachment, and absence of labyrinth. These defects result in embryo death by 10.5 dpc. Trophoblast stem cell lines derived from Erf(dl1/dl1) knockout blastocysts exhibit delayed differentiation and decreased expression of spongiotrophoblast markers, consistent with the persisting chorion layer, the expanded giant cell layer, and the diminished spongiotrophoblast layer observed in vivo. Our data suggest that attenuation of FGF/Erk signaling and consecutive Erf nuclear localization and function is required for extraembryonic ectoderm differentiation, ectoplacental cone cavity closure, and chorioallantoic attachment.
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Affiliation(s)
- Chara Papadaki
- Medical School, University of Crete, Voutes, Heraklion, Crete 710 03, Greece
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174
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Bates CM. Role of fibroblast growth factor receptor signaling in kidney development. Pediatr Nephrol 2007; 22:343-9. [PMID: 16932896 DOI: 10.1007/s00467-006-0239-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Accepted: 06/07/2006] [Indexed: 11/28/2022]
Abstract
Fibroblast growth factor receptors (Fgfrs) are expressed in the ureteric bud and metanephric mesenchyme of the developing kidney. Furthermore, in vitro and in vivo studies have shown that exogenous fibroblast growth factors (Fgfs) increase growth and maturation of the metanephric mesenchyme and ureteric bud. Deletion of fgf7, fgf10, and fgfr2IIIb (the receptor isoform that binds Fgf7 and Fgf10) in mice lead to smaller kidneys with fewer collecting ducts and nephrons. Overexpression of a dominant negative receptor isoform in transgenic mice has revealed more striking defects including renal aplasia or severe dysplasia. Moreover, deletion of many fgf ligands and receptors in mice results in early embryonic lethality, making it difficult to determine their roles in kidney development. Recently, conditional targeting approaches revealed that deletion of fgf8 from the metanephric mesenchyme interrupts nephron formation. Furthermore, deletion of fgfr2 from the ureteric bud resulted in both ureteric bud branching and stromal mesenchymal patterning defects. Deletion of both fgfr1 and fgfr2 in the metanephric mesenchyme resulted in renal aplasia, characterized by defects in metanephric mesenchyme formation and initial ureteric bud elongation and branching. Thus, Fgfr signaling is critical for growth and patterning of all renal lineages at early and later stages of kidney development.
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MESH Headings
- Animals
- Fibroblast Growth Factors/pharmacology
- Kidney/abnormalities
- Kidney/embryology
- Kidney/metabolism
- Mice
- Mice, Knockout
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/physiology
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/physiology
- Receptors, Fibroblast Growth Factor/drug effects
- Receptors, Fibroblast Growth Factor/genetics
- Receptors, Fibroblast Growth Factor/metabolism
- Receptors, Fibroblast Growth Factor/physiology
- Signal Transduction
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Affiliation(s)
- Carlton M Bates
- Center for Cell and Developmental Biology, Columbus Children's Research Institute, 700 Children's Drive, Columbus, OH 43205, USA.
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175
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Eswarakumar VP, Schlessinger J. Skeletal overgrowth is mediated by deficiency in a specific isoform of fibroblast growth factor receptor 3. Proc Natl Acad Sci U S A 2007; 104:3937-42. [PMID: 17360456 PMCID: PMC1820687 DOI: 10.1073/pnas.0700012104] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Fibroblast growth factor receptor 3 (FGFR3) plays an important role in the control of chondrocyte proliferation and differentiation, a process critical for normal development of the skeleton. To reveal the contributions of the epithelial Fgfr3b isoform and the mesenchymal Fgfr3c isoform to skeletal overgrowth seen in mice, in which both isoforms have been inactivated (Fgf3c(-/-) mice), we have generated mice in which each of the two Fgfr3 isoforms has been selectively inactivated. Whereas no apparent phenotype was detected in Fgfr3b(-/-) mice, strong stimulation of chondrocyte proliferation in the growth plates of Fgf3c(-/-) mice caused dramatic skeletal overgrowth and other skeletal abnormalities resembling the phenotype of mice deficient in both Fgfr3 isoforms. In addition, Fgfr3c(-/-) mice exhibited decreased bone mineral density in the cortical and trabecular bone, whereas the bone mineral density of Fgfr3b(-/-) mice resembled that of WT mice. These experiments demonstrated that the mesenchymal Fgfr3c isoform is responsible for controlling chondrocyte proliferation and differentiation that mediate normal skeletal development, whereas the epithelial Fgfr3b isoform does not contribute toward this process.
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Affiliation(s)
| | - Joseph Schlessinger
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520
- *To whom correspondence should be addressed at:
Department of Pharmacology, Yale University School of Medicine, P.O. Box 208066, New Haven, CT 06520-8066. E-mail:
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176
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Kuslak SL, Marker PC. Fibroblast growth factor receptor signaling through MEK-ERK is required for prostate bud induction. Differentiation 2007; 75:638-51. [PMID: 17309601 DOI: 10.1111/j.1432-0436.2006.00161.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The urogenital sinus (UGS) is specified as prostate in mice around embryonic day 15.5 as indicated by expression of the transcription factor Nkx3.1. Shortly thereafter, growth of epithelial buds into the UGS mesenchyme initiates prostatic morphogenesis. A comparison of male and female UGSs in vivo demonstrated sexually dimorphic expression of branching morphogenesis regulatory genes coincident with epithelial budding including Bmp7, Gli1, Gli2, Fgf10, Ptch1, and Shh. A comparison of UGSs grown with or without testosterone in serum-free organ cultures showed that some, but not all sexually dimorphic differences observed during prostate bud induction, were effectively modeled in vitro. Organ cultures were then used to investigate the role of fibroblast growth factor receptor (FGFR) signaling during prostatic induction. Blocking FGFR activation with PD173074 showed that activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in the UGS is dependent on FGFR signaling. Furthermore, inhibiting either FGFR activation with PD173074 or ERK1/2 activation with UO126 blocked all morphogenesis, proliferation, and gene expression changes induced by androgens in the UGS. These data reveal a previously unknown role for ERK1/2 during prostate bud induction. They also show that signaling by FGFRs through ERK1/2 is required for androgen-induced budding morphogenesis, proliferation, and gene expression during prostate bud induction.
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Affiliation(s)
- Sheri L Kuslak
- Department of Genetics, Cell Biology and Development, University of Minnesota Comprehensive Cancer Center, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN 55455, USA
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177
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Kojima T, Chang JH, Azar DT. Proangiogenic role of ephrinB1/EphB1 in basic fibroblast growth factor-induced corneal angiogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:764-73. [PMID: 17255342 PMCID: PMC1851865 DOI: 10.2353/ajpath.2007.060487] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/25/2006] [Indexed: 11/20/2022]
Abstract
Corneal neovascularization is a vision-threatening condition caused by various ocular pathological conditions. The aim of this study was to evaluate the function of the ephrin ligands and Eph receptors in vitro and in vivo in corneal angiogenesis in a mouse model. The Eph tyrosine kinase receptors and their ligands, ephrins, are expressed on the cell surface. The functions of Eph and ephrins have been shown to regulate axonal guidance, segmentation, cell migration, and angiogenesis. Understanding the roles of Eph and ephrin in corneal angiogenesis may provide a therapeutic intervention for the treatment of angiogenesis-related disorders. Immunohistochemical studies demonstrated that ephrinB1 and EphB1 were expressed in basic fibroblast growth factor (bFGF)-induced vascularized corneas. EphB1 was specifically colocalized with vascular endothelial marker CD31 surrounded by type IV collagen. EphrinB1 was expressed in corneal-resident keratocytes and neutrophils. Recombinant ephrinB1-Fc, which induces EphB receptor activation, enhanced bFGF-induced tube formation in an in vitro aortic ring assay and promoted bFGF-induced corneal angiogenesis in vivo in a corneal pocket assay. Synergistically enhanced and sustained activation of extracellular signal-regulated kinase was noted in vascular endothelial cell lines after stimulation with ephrin B1 and bFGF combinations. These results suggest that ephrinB1 plays a synergistic role in corneal neovascularization.
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Affiliation(s)
- Takashi Kojima
- Department of Ophthalmology, Massachusetts Eyue and Ear Infirmary, and the Schepens Eye Research Institute, Harvard Medical School, Boston, MA, USA
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178
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Popławski NJ, Swat M, Gens JS, Glazier JA. Adhesion between cells, diffusion of growth factors, and elasticity of the AER produce the paddle shape of the chick limb. PHYSICA A 2007; 373:521-532. [PMID: 18167520 PMCID: PMC2168394 DOI: 10.1016/j.physa.2006.05.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A central question in developmental biology is how cells interact to organize into tissues? In this paper, we study the role of mesenchyme-ectoderm interaction in the growing chick limb bud using Glazier and Graner's cellular Potts model, a grid-based stochastic framework designed to simulate cell interactions and movement. We simulate cellular mechanisms including cell adhesion, growth, and division and diffusion of morphogens, to show that differential adhesion between the cells, diffusion of growth factors through the extracellular matrix, and the elastic properties of the apical ectodermal ridge together can produce the proper shape of the limb bud.
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Affiliation(s)
- Nikodem J Popławski
- Biocomplexity Institute and Department of Physics, Indiana University, 727 East Third Street, Swain Hall West 117, Bloomington, IN 47405-7105, USA
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179
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AMARNATH D, LI X, KATO Y, TSUNODA Y. Gene Expression in Individual Bovine Somatic Cell Cloned Embryos at the 8-cell and Blastocyst Stages of Preimplantation Development. J Reprod Dev 2007; 53:1247-63. [DOI: 10.1262/jrd.19096] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Dasari AMARNATH
- Laboratory of Animal Reproduction, College of Agriculture, Kinki University
| | - Xiangping LI
- Laboratory of Animal Reproduction, College of Agriculture, Kinki University
| | - Yoko KATO
- Laboratory of Animal Reproduction, College of Agriculture, Kinki University
| | - Yukio TSUNODA
- Laboratory of Animal Reproduction, College of Agriculture, Kinki University
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180
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Eswarakumar VP, Özcan F, Lew ED, Bae JH, Tomé F, Booth CJ, Adams DJ, Lax I, Schlessinger J. Attenuation of signaling pathways stimulated by pathologically activated FGF-receptor 2 mutants prevents craniosynostosis. Proc Natl Acad Sci U S A 2006; 103:18603-8. [PMID: 17132737 PMCID: PMC1693709 DOI: 10.1073/pnas.0609157103] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Craniosynostosis, the fusion of one or more of the sutures of the skull vault before the brain completes its growth, is a common (1 in 2,500 births) craniofacial abnormality, approximately 20% of which occurrences are caused by gain-of-function mutations in FGF receptors (FGFRs). We describe a genetic and pharmacological approach for the treatment of a murine model system of Crouzon-like craniosynostosis induced by a dominant mutation in Fgfr2c. Using genetically modified mice, we demonstrate that premature fusion of sutures mediated by Crouzon-like activated Fgfr2c mutant is prevented by attenuation of signaling pathways by selective uncoupling between the docking protein Frs2alpha and activated Fgfr2c, resulting in normal skull development. We also demonstrate that attenuation of Fgfr signaling in a calvaria organ culture with an Fgfr inhibitor prevents premature fusion of sutures without adversely affecting calvaria development. These experiments show that attenuation of FGFR signaling by pharmacological intervention could be applied for the treatment of craniosynostosis or other severe bone disorders caused by mutations in FGFRs that currently have no treatment.
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Affiliation(s)
| | | | | | | | - F. Tomé
- *Department of Pharmacology and
| | - C. J. Booth
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520; and
| | - D. J. Adams
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT 06030
| | - I. Lax
- *Department of Pharmacology and
| | - J. Schlessinger
- *Department of Pharmacology and
- To whom correspondence should be addressed. E-mail:
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181
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Nakazawa F, Nagai H, Shin M, Sheng G. Negative regulation of primitive hematopoiesis by the FGF signaling pathway. Blood 2006; 108:3335-43. [PMID: 16888091 DOI: 10.1182/blood-2006-05-021386] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
AbstractHematopoiesis is controlled by multiple signaling molecules during embryonic and postnatal development. The function of the fibroblast growth factor (FGF) pathway in this process is unclear. Here we show that FGF plays a key role in the regulation of primitive hematopoiesis in chicks. Using hemoglobin mRNA expression as a sensitive marker, we demonstrate that timing of blood differentiation can be separated from that of initial mesoderm patterning and subsequent migration. High FGF activity inhibits primitive blood differentiation and promotes endothelial cell fate. Conversely, inhibition of FGFR activity leads to ectopic blood formation and down-regulation of endothelial markers. Expression and functional analyses indicate that FGFR2 is the key receptor mediating these effects. The FGF pathway regulates primitive hematopoiesis by modulating Gata1 expression level and activity. We propose that the FGF pathway mediates repression of globin gene expression and that its removal is essential before terminal differentiation can occur.
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Affiliation(s)
- Fumie Nakazawa
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
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182
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Blak AA, Naserke T, Saarimäki-Vire J, Peltopuro P, Giraldo-Velasquez M, Vogt Weisenhorn DM, Prakash N, Sendtner M, Partanen J, Wurst W. Fgfr2 and Fgfr3 are not required for patterning and maintenance of the midbrain and anterior hindbrain. Dev Biol 2006; 303:231-43. [PMID: 17150206 DOI: 10.1016/j.ydbio.2006.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Revised: 10/12/2006] [Accepted: 11/06/2006] [Indexed: 11/16/2022]
Abstract
The mid-/hindbrain organizer (MHO) is characterized by the expression of a network of genes, which controls the patterning and development of the prospective midbrain and anterior hindbrain. One key molecule acting at the MHO is the fibroblast growth factor (Fgf) 8. Ectopic expression of Fgf8 induces genes that are normally expressed at the mid-/hindbrain boundary followed by the induction of midbrain and anterior hindbrain structures. Inactivation of the Fgf receptor (Fgfr) 1 gene, which was thought to be the primary transducer of the Fgf8 signal at the MHO, in the mid-/hindbrain region, leads to a deletion of dorsal structures of the mid-/hindbrain region, whereas ventral tissues are less severely affected. This suggests that other Fgfrs might be responsible for ventral mid-/hindbrain region development. Here we report the analysis of Fgfr2 conditional knockout mice, lacking the Fgfr2 in the mid-/hindbrain region and of Fgfr3 knockout mice with respect to the mid-/hindbrain region. In both homozygous mouse mutants, patterning of the mid-/hindbrain region is not altered, neuronal populations develop normal and are maintained into adulthood. This analysis shows that the Fgfr2 and the Fgfr3 on their own are dispensable for the development of the mid-/hindbrain region. We suggest functional redundancy of Fgf receptors in the mid-/hindbrain region.
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Affiliation(s)
- Alexandra A Blak
- GSF-National Research Center for Environment and Health, Institute of Developmental Genetics, Ingolstadter Landstrasse 1, 85764 Neuherberg, Germany
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183
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Abstract
Since the days of Hans Spemann, the ocular lens has served as one of the most important developmental systems for elucidating fundamental processes of induction and differentiation. More recently, studies in the lens have contributed significantly to our understanding of cell cycle regulation and apoptosis. Over 20 years of accumulated evidence using several different vertebrate species has suggested that fibroblast growth factors (FGFs) and/or fibroblast growth factor receptors (FGFRs) play a key role in lens development. FGFR signaling has been implicated in lens induction, lens cell proliferation and survival, lens fiber differentiation and lens regeneration. Here we will review and discuss historical and recent evidence suggesting that (FGFR) signaling plays a vital and universal role in multiple aspects of lens development.
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184
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Abstract
The ureteric bud (UB) is an outgrowth of the Wolffian duct, which undergoes a complex process of growth, branching, and remodeling, to eventually give rise to the entire urinary collecting system during kidney development. Understanding the mechanisms that control this process is a fascinating problem in basic developmental biology, and also has considerable medical significance. Over the past decade, there has been significant progress in our understanding of renal branching morphogenesis and its regulation, and this review focuses on several areas in which there have been recent advances. The first section deals with the normal process of UB branching morphogenesis, and methods that have been developed to better observe and describe it. The next section discusses a number of experimental methodologies, both established and novel, that make kidney development in the mouse a powerful and attractive experimental system. The third section discusses some of the cellular processes that are likely to underlie UB branching morphogenesis, as well as recent data on cell lineages within the growing UB. The fourth section summarizes our understanding of the roles of two groups of growth factors that appear to be particularly important for the regulation of UB outgrowth and branching: GDNF and FGFs, which stimulate this process via tyrosine kinase receptors, and members of the TGFbeta family, including BMP4 and Activin A, which generally inhibit UB formation and branching.
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Affiliation(s)
- Frank Costantini
- Department of Genetics and Development, Columbia University Medical Center, 701 W. 168th St. New York, NY 10032, USA.
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185
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Cross JC, Nakano H, Natale DRC, Simmons DG, Watson ED. Branching morphogenesis during development of placental villi. Differentiation 2006; 74:393-401. [PMID: 16916377 DOI: 10.1111/j.1432-0436.2006.00103.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The placenta forms a complex interface between the mother and fetus during development that is designed for efficient nutrient exchange. A large surface area is created by extensive branching morphogenesis of the trophoblast-derived epithelium to create a villous network, called the labyrinth in rodents. These villi are subsequently vascularized with an elaborate capillary network. Morphogenesis begins with selection of a subset of trophoblast cells in the basal layer of the chorion that express the Gcm1 transcription factor. These cells leave the cell cycle and undergo cell shape changes that initiate a process of involution to create primary villi into which fetal blood vessels grow. Much less is known about the regulation of subsequent events in branching, certainly compared with other organs. However, over 60 different mouse mutants have defects during later labyrinth development. Some of these mutant genes encode components of signaling pathways such as the fibroblast growth factor and Wnt pathways that play evolutionarily conserved roles in other branched organs, These mutants represent a still largely untapped resource as most of them have not been studied in detail in relation to placental morphogenesis.
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Affiliation(s)
- James C Cross
- Department of Biochemistry & Molecular Biology, University of Calgary, HSC Room 2279, 3330 Hospital Drive NW, Calgary AB, Canada T2N 4N1.
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186
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Coumoul X, Deng CX. RNAi in mice: a promising approach to decipher gene functions in vivo. Biochimie 2006; 88:637-43. [PMID: 16426724 DOI: 10.1016/j.biochi.2005.11.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Accepted: 11/29/2005] [Indexed: 10/25/2022]
Abstract
RNA interference (RNAi) is a simple and powerful tool widely used to study gene functions in many species. Vector-based systems using RNA polymerase III promoters have been developed to achieve stable expression of small interfering RNA (siRNA) or small hairpin RNA (shRNA) in mammalian cells. Recent investigations demonstrated that when, combined with the Cre-loxP system, the vector-based RNAi can be used to achieve conditional or tissue specific knockdown of endogenous genes with high efficiency in mice. Here, we review these recent progresses and discuss the advantages, limitations and future development of this emerging technology.
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Affiliation(s)
- Xavier Coumoul
- INSERM UMR-S 490, Unite de Toxicologie Moléculaire, 45, rue des Saints-Pères, 75270 Paris cedex 06, France.
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187
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Newman EA, Muh SJ, Hovhannisyan RH, Warzecha CC, Jones RB, McKeehan WL, Carstens RP. Identification of RNA-binding proteins that regulate FGFR2 splicing through the use of sensitive and specific dual color fluorescence minigene assays. RNA (NEW YORK, N.Y.) 2006; 12:1129-41. [PMID: 16603716 PMCID: PMC1464843 DOI: 10.1261/rna.34906] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Accepted: 02/16/2006] [Indexed: 05/04/2023]
Abstract
We have developed a series of fluorescent splicing reporter minigenes for the establishment of cell-based screens to identify splicing regulatory proteins. A key technical advance in the application of these reporters was the use of two different fluorescent proteins: EGFP and monomeric Red Fluorescent Protein (mRFP). Through establishment of stable cell lines expressing such dual color fluorescent reporters, these minigenes can be used to perform enhanced screens for splicing regulatory proteins. As an example of such applications we generated fluorescent minigenes that can be used to determine the splicing of mutually exclusive FGFR2 exons IIIb and IIIc by flow cytometry. One minigene contained a coding sequence for EGFP whose translation was dependent on splicing of exon IIIb, whereas a second minigene required exon IIIc splicing for translation of an mRFP coding sequence. Stable incorporation of both minigenes into cells that express endogenous FGFR2-IIIb or FGFR2-IIIc resulted in EGFP or mRFP fluorescence, respectively. Cells stably transfected with both minigenes were used to screen a panel of cDNAs encoding known splicing regulatory proteins, and several were identified that induced a switch in splicing that could be detected specifically by an increase in green, but not red, fluorescence. We further demonstrated additional minigenes that can be used in dual color fluorescent screens for identification of splicing regulatory proteins that function through specific intronic splicing enhancer elements (ISEs). The methods and minigene designs described here should be adaptable for broader applications in identification of factors and mechanisms involved in alternative splicing of numerous other gene transcripts.
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Affiliation(s)
- Emily A Newman
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
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188
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Jacob AL, Smith C, Partanen J, Ornitz DM. Fibroblast growth factor receptor 1 signaling in the osteo-chondrogenic cell lineage regulates sequential steps of osteoblast maturation. Dev Biol 2006; 296:315-28. [PMID: 16815385 PMCID: PMC2077084 DOI: 10.1016/j.ydbio.2006.05.031] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 05/02/2006] [Accepted: 05/23/2006] [Indexed: 12/29/2022]
Abstract
Mutations in fibroblast growth factor receptors (Fgfrs) 1-3 cause skeletal disease syndromes in humans. Although these Fgfrs are expressed at various stages of chondrocyte and osteoblast development, their function in specific skeletal cell types is poorly understood. Using conditional inactivation of Fgfr1 in osteo-chondrocyte progenitor cells and in differentiated osteoblasts, we provide evidence that FGFR1 signaling is important for different stages of osteoblast maturation. Examination of osteogenic markers showed that inactivation of FGFR1 in osteo-chondro-progenitor cells delayed osteoblast differentiation, but that inactivation of FGFR1 in differentiated osteoblasts accelerated differentiation. In vitro osteoblast cultures recapitulated the in vivo effect of FGFR1 on stage-specific osteoblast maturation. In immature osteoblasts, FGFR1 deficiency increased proliferation and delayed differentiation and matrix mineralization, whereas in differentiated osteoblasts, FGFR1 deficiency enhanced mineralization. Furthermore, FGFR1 deficiency in differentiated osteoblasts resulted in increased expression of Fgfr3, a molecule that regulates the activity of differentiated osteoblasts. Mice lacking Fgfr1, either in progenitor cells or in differentiated osteoblasts, showed increased bone mass as adults. These data demonstrate that signaling through FGFR1 in osteoblasts is necessary to maintain the balance between bone formation and remodeling through a direct effect on osteoblast maturation.
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MESH Headings
- Animals
- Bone and Bones/abnormalities
- Bone and Bones/embryology
- Bone and Bones/enzymology
- Cell Differentiation/genetics
- Cell Differentiation/physiology
- Cell Lineage/genetics
- Cell Lineage/physiology
- Cells, Cultured
- Chondrocytes/cytology
- Chondrocytes/enzymology
- Chondrocytes/physiology
- Hypertrophy/genetics
- Mice
- Mice, Knockout
- Mice, Transgenic
- Osteoblasts/cytology
- Osteoblasts/enzymology
- Osteoblasts/physiology
- Receptor, Fibroblast Growth Factor, Type 1/biosynthesis
- Receptor, Fibroblast Growth Factor, Type 1/deficiency
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/physiology
- Signal Transduction/genetics
- Signal Transduction/physiology
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Affiliation(s)
- Anne L. Jacob
- Department of Molecular Biology and Pharmacology, Washington University Medical School, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Craig Smith
- Department of Molecular Biology and Pharmacology, Washington University Medical School, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Juha Partanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - David M. Ornitz
- Department of Molecular Biology and Pharmacology, Washington University Medical School, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
- * Corresponding author. E-mail address: (D.M. Ornitz)
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189
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Arima T, Hata K, Tanaka S, Kusumi M, Li E, Kato K, Shiota K, Sasaki H, Wake N. Loss of the maternal imprint in Dnmt3Lmat-/- mice leads to a differentiation defect in the extraembryonic tissue. Dev Biol 2006; 297:361-73. [PMID: 16920095 DOI: 10.1016/j.ydbio.2006.05.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 05/01/2006] [Accepted: 05/03/2006] [Indexed: 10/24/2022]
Abstract
DNA methylation of the genome is essential for mammalian development and plays crucial roles in a variety of biological processes including genomic imprinting. Although the DNA methyltransferase 3-like (Dnmt3L) protein lacks DNA methylase activity, it is thought to establish the maternal imprint in combination with the functional DNA methyltransferases. Oogenesis apparently proceeds normally in female mice homozygous for a targeted deletion of Dnmt3L, but their heterozygous offspring (Dnmt3L(mat-/-)) die before midgestation due to an imprinting defect. In this study, we show that Dnmt3L is required for the establishment of maternal methylation imprints both in the embryos and the placentae and that the placentae of these embryos develop abnormally. There is a defect in the formation of the labyrinth, reduced formation of the spongiotrophoblast layer, excess trophoblast giant cells and insufficient attachment between the chorion layer and the ectoplacental cone. In addition, we demonstrate arrest of proliferation of the extraembryonic tissue without apoptosis in vivo and a disturbance of the cell fate of Dnmt3L(mat-/-) trophoblastic stem cells in vitro. Furthermore, we report that DNA methylation during oogenesis is essential for the establishment of imprinting Mash2. These findings provide evidence that not only is DNA methylation required for the appropriate maternal imprint in the placenta but that the appropriate imprint is absolutely required for vertebrate placentation.
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Affiliation(s)
- Takahiro Arima
- Department of Molecular Genetics, Division of Molecular and Cell Therapeutics, Medical Institute of Bioregulation, Kyusyu University, Beppu, Oita 874-0838, Japan.
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190
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del Moral PM, De Langhe SP, Sala FG, Veltmaat JM, Tefft D, Wang K, Warburton D, Bellusci S. Differential role of FGF9 on epithelium and mesenchyme in mouse embryonic lung. Dev Biol 2006; 293:77-89. [PMID: 16494859 DOI: 10.1016/j.ydbio.2006.01.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 11/23/2005] [Accepted: 01/23/2006] [Indexed: 12/31/2022]
Abstract
Mesothelial Fibroblast Growth Factor 9 (Fgf9) has been demonstrated by inactivation studies in mouse to be critical for the proliferation of the mesenchyme. We now show that Fgf9 is also expressed at significant levels in the distal epithelium from the mid-pseudoglandular stages. Using mesenchymal-free lung endoderm culture, we show that FGF9 triggers the proliferation of the distal epithelium leading to the formation of a cyst-like structure. On embryonic Fgfr2b-/- lungs, FGF9 induces proliferation of the mesenchyme but fails to trigger a similar effect on the epithelium, therefore involving the FGFR2b receptor in the proliferative response of the epithelium to FGF9. While FGF9 inhibits the differentiation of the mesenchyme, the epithelium appears to differentiate normally. At the molecular level, FGF9 up-regulates Fgf10 expression in the mesenchyme likely via increased expression of Tbx4 and 5 and controls the transcription of Hedgehog targets Ptc and Gli-1 in a Hedgehog-independent manner. We also show that FGF9 inhibits the activation of the canonical Wnt pathway in the epithelium by increasing Dkk1 expression, a canonical Wnt antagonist. Our work shows for the first time that FGF9 acts on the epithelium involving FGFR2b to control its proliferation but not its differentiation and contributes to the regulation of canonical Wnt signaling in the epithelium.
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Affiliation(s)
- Pierre-Marie del Moral
- Developmental Biology Program, Saban Research Institute of Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
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191
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Yang W, Klaman LD, Chen B, Araki T, Harada H, Thomas SM, George EL, Neel BG. An Shp2/SFK/Ras/Erk signaling pathway controls trophoblast stem cell survival. Dev Cell 2006; 10:317-27. [PMID: 16516835 DOI: 10.1016/j.devcel.2006.01.002] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 12/28/2005] [Accepted: 01/05/2006] [Indexed: 11/18/2022]
Abstract
Little is known about how growth factors control tissue stem cell survival and proliferation. We analyzed mice with a null mutation of Shp2 (Ptpn11), a key component of receptor tyrosine kinase signaling. Null embryos die peri-implantation, much earlier than mice that express an Shp2 truncation. Shp2 null blastocysts initially develop normally, but they subsequently exhibit inner cell mass death, diminished numbers of trophoblast giant cells, and failure to yield trophoblast stem (TS) cell lines. Molecular markers reveal that the trophoblast lineage, which requires fibroblast growth factor-4 (FGF4), is specified but fails to expand normally. Moreover, deletion of Shp2 in TS cells causes rapid apoptosis. We show that Shp2 is required for FGF4-evoked activation of the Src/Ras/Erk pathway that culminates in phosphorylation and destabilization of the proapoptotic protein Bim. Bim depletion substantially blocks apoptosis and significantly restores Shp2 null TS cell proliferation, thereby establishing a key mechanism by which FGF4 controls stem cell survival.
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Affiliation(s)
- Wentian Yang
- Cancer Biology Program, Division of Hematology/Oncology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
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192
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Abstract
The Fgf signalling pathway is highly conserved in evolution and plays crucial roles in development. In the craniofacial region, it is involved in almost all structure development from early patterning to growth regulation. In craniofacial skeletogenesis, the Fgf signal pathway plays important roles in suture and synchondrosis regulation. Mutations of FGF receptors relate to syndromatic and non-syndromatic craniosynostosis. The Fgf10/Fgfr2b signal loop is critical for palatogenesis and submandibular gland formation. Perturbation of the Fgf signal is a possible mechanism of palatal cleft. Fgf10 haploinsufficiency has been identified as the cause of autosomal dominant aplasia of lacrimal and salivary glands. The Fgf signal is also a key regulator of tooth formation: in the absence of Fgfr2b tooth development is arrested at the bud stage. Fgfr4 has recently been identified as the key signal mediator in myogenesis. In this review, these aspects are discussed in detail with a focus on the most recent advances.
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Affiliation(s)
- X Nie
- Section of Anatomy and Cell Biology, Department of Biomedicine, University of Bergen, Bergen, Norway.
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193
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Morin-Kensicki EM, Boone BN, Howell M, Stonebraker JR, Teed J, Alb JG, Magnuson TR, O'Neal W, Milgram SL. Defects in yolk sac vasculogenesis, chorioallantoic fusion, and embryonic axis elongation in mice with targeted disruption of Yap65. Mol Cell Biol 2006; 26:77-87. [PMID: 16354681 PMCID: PMC1317614 DOI: 10.1128/mcb.26.1.77-87.2006] [Citation(s) in RCA: 316] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
YAP is a multifunctional adapter protein and transcriptional coactivator with several binding partners well described in vitro and in cell culture. To explore in vivo requirements for YAP, we generated mice carrying a targeted disruption of the Yap gene. Homozygosity for the Yap(tm1Smil) allele (Yap-/-) caused developmental arrest around E8.5. Phenotypic characterization revealed a requirement for YAP in yolk sac vasculogenesis. Yolk sac endothelial and erythrocyte precursors were specified as shown by histology, PECAM1 immunostaining, and alpha globin expression. Nonetheless, development of an organized yolk sac vascular plexus failed in Yap-/- embryos. In striking contrast, vasculogenesis proceeded in both the allantois and the embryo proper. Mutant embryos showed patterned gene expression domains along the anteroposterior neuraxis, midline, and streak/tailbud. Despite this evidence of proper patterning and tissue specification, Yap-/- embryos showed developmental perturbations that included a notably shortened body axis, convoluted anterior neuroepithelium, caudal dysgenesis, and failure of chorioallantoic fusion. These results reveal a vital requirement for YAP in the developmental processes of yolk sac vasculogenesis, chorioallantoic attachment, and embryonic axis elongation.
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Affiliation(s)
- Elizabeth M Morin-Kensicki
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, USA.
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194
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Moon AM, Guris DL, Seo JH, Li L, Hammond J, Talbot A, Imamoto A. Crkl deficiency disrupts Fgf8 signaling in a mouse model of 22q11 deletion syndromes. Dev Cell 2006; 10:71-80. [PMID: 16399079 PMCID: PMC1780033 DOI: 10.1016/j.devcel.2005.12.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Revised: 11/17/2005] [Accepted: 12/06/2005] [Indexed: 10/25/2022]
Abstract
Deletions on chromosome 22q11.21 disrupt pharyngeal and cardiac development and cause DiGeorge and related human syndromes. CRKL (CRK-Like) lies within 22q11.21, and Crkl-/- mice have phenotypic features of 22q11 deletion (del22q11) syndromes. While human FGF8 does not localize to 22q11, deficiency of Fgf8 also generates many features of del22q11 syndrome in mice. Since Fgf8 signals via receptor-type tyrosine kinases, and Crk family adaptor proteins transduce intracellular signals downstream of tyrosine kinases, we investigated whether Crkl mediates Fgf8 signaling. In addition to discovering genetic interactions between Crkl and Fgf8 during morphogenesis of structures affected in del22q11 syndrome, we found that Fgf8 induces tyrosine phosphorylation of FgfRs 1 and 2 and their binding to Crkl. Crkl is required for normal cellular responses to Fgf8, including survival and migration, Erk activation, and target gene expression. These findings provide mechanistic insight into disrupted intercellular interactions in the pathogenesis of malformations seen in del22q11 syndrome.
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MESH Headings
- Animals
- Apoptosis
- Blotting, Western/methods
- Bone and Bones/embryology
- Bone and Bones/metabolism
- Cardiovascular System/embryology
- Cardiovascular System/metabolism
- Cell Count/methods
- Cells, Cultured
- Chemotactic Factors/metabolism
- Chromosomes, Human, Pair 22
- DiGeorge Syndrome/genetics
- DiGeorge Syndrome/metabolism
- Disease Models, Animal
- Embryo, Mammalian
- Enzyme Activation
- Fibroblast Growth Factor 8/metabolism
- Fluorescent Antibody Technique/methods
- Gene Deletion
- Gene Expression Regulation, Developmental/genetics
- Genotype
- Humans
- Mice
- Mice, Knockout
- Models, Biological
- Neural Crest/metabolism
- Pharynx/embryology
- Pharynx/metabolism
- Phenotype
- Proto-Oncogene Proteins c-crk/deficiency
- Receptors, Fibroblast Growth Factor/metabolism
- Signal Transduction/physiology
- Time Factors
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Affiliation(s)
- Anne M Moon
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA.
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195
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Poladia DP, Kish K, Kutay B, Hains D, Kegg H, Zhao H, Bates CM. Role of fibroblast growth factor receptors 1 and 2 in the metanephric mesenchyme. Dev Biol 2006; 291:325-39. [PMID: 16442091 DOI: 10.1016/j.ydbio.2005.12.034] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 11/21/2005] [Accepted: 12/16/2005] [Indexed: 10/25/2022]
Abstract
To determine the importance of fibroblast growth factor receptors (fgfrs) 1 and 2 in the metanephric mesenchyme, we generated conditional knockout mice (fgfr(Mes-/-)). Fgfr1(Mes-/-) and fgfr2(Mes-/-) mice develop normal-appearing kidneys. Deletion of both receptors (fgfr1/2(Mes-/-)) results in renal aplasia. Fgfr1/2(Mes-/-) mice develop a ureteric bud (and occasionally an ectopic bud) that does not elongate or branch, and the mice do not develop an obvious metanephric mesenchyme. By in situ hybridization, regions of mutant mesenchyme near the ureteric bud(s) express Eya1 and Six1, but not Six2, Sall1, or Pax2, while the ureteric bud expresses Ret and Pax2 normally. Abnormally high rates of apoptosis and relatively low rates of proliferation are present in mutant mesenchyme dorsal to the mutant ureteric bud at embryonic day (E) 10.5, while mutant ureteric bud tissues undergo high rates of apoptosis by E11.5. Thus, fgfr1 and fgfr2 together are critical for normal formation of metanephric mesenchyme. While the ureteric bud(s) initiates, it does not elongate or branch infgfr1/2(Mes-/-) mice. In metanephric mesenchymal rudiments, fgfr1 and fgfr2 appear to function downstream of Eya1 and Six1, but upstream of Six2, Sall1, and Pax2. Finally, this is the first example of renal aplasia in a conditional knockout model.
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Affiliation(s)
- Deepali Pitre Poladia
- Center for Cell and Vascular Biology, Columbus Children's Research Institute, 700 Children's Drive, Columbus, OH 43205, USA
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196
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Havens BA, Rodgers B, Mina M. Tissue-specific expression of Fgfr2b and Fgfr2c isoforms, Fgf10 and Fgf9 in the developing chick mandible. Arch Oral Biol 2006; 51:134-45. [PMID: 16105644 DOI: 10.1016/j.archoralbio.2005.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 06/06/2005] [Accepted: 06/08/2005] [Indexed: 10/25/2022]
Abstract
Experimental evidence has demonstrated the importance of FGF signalling in morphogenesis of the mandibular processes. FGFs transmit their signals through four tyrosine kinase transmembrane receptors (FGFRs). Alternative splicing in FGFRs including FGFR2 generates different isoforms that exhibit different ligand-specificities, exclusive tissue distributions and specific biological functions. Despite extensive information regarding the isoform-specific patterns of expression Fgfr2c and Fgfr2b during morphogenesis of many organs, a comparative analysis of these specific isoforms in the chick mandible has not been reported. To better understand the function of FGFR2 in mandibular morphogenesis, we have analysed the expression Fgfr2b, Fgfr2c and their putative ligands Fgf10 and Fgf9, in the developing chick mandibular processes by in situ hybridisation and RT-PCR. Our observations show that Fgfr2b was primarily expressed in the mandibular epithelium while Fgfr2c was expressed in the mandibular mesenchyme including Meckel's cartilage. Fgf9 and Fgf10 were expressed in a variety of craniofacial regions including the mandibular epithelium and mesenchyme respectively. The temporal and spatial distributions of Fgfr2b, Fgfr2c, Fgf10 and Fgf9 in the developing mandible reported in this study make them attractive candidates for involvement in epithelial-mesenchymal signalling interactions that are known to be necessary for proper mandibular outgrowth and morphogenesis.
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Affiliation(s)
- Bruce A Havens
- Departments of Orthodontics, School of Dental Medicine, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, USA
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197
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Zhong W, Wang QT, Sun T, Wang F, Liu J, Leach R, Johnson A, Puscheck EE, Rappolee DA. FGF Ligand Family mRNA Expression Profile for Mouse Preimplantation Embryos, Early Gestation Human Placenta, and Mouse Trophoblast Stem Cells. Mol Reprod Dev 2006; 73:540-50. [PMID: 16470835 DOI: 10.1002/mrd.20417] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Signaling by fibroblast growth factor (FGF) is essential is for trophoblast stem (TS) cells and preimplantation embryos. FGF4 provides essential signaling, but the expression of the complete set of 23 FGF family members has not been analyzed. Here, semi-quantitative RT-PCR and microarray analyses were used to define expression of all FGF ligand mRNA. RT-PCR was done for developmentally important FGF subfamilies, FGF10/FGF22 and FGF8/FGF17/FGF18 as well as FGF11. FGF4 and FGF18 are detected at highest levels by RT-PCR and microarrays. FGF10 was detected at low levels in both assays. FGF11 was detected at moderate levels by microarray, but not by RT-PCR. FGF17 was detected at low levels by array and moderate levels by RT-PCR. FGF8 and FGF22 were detected by RT-PCR, but not by microarrays during late cleavage divisions. FGF8, FGF5, and FGF9 were detected in the oocyte by microarray. FGF2, FGF3, and FGF7 were not detected by RT-PCR or microarrays and FGF13, FGF14, and FGF23 were not detected by microarray. Since a major role of FGF is to maintain TS cells, we tested human and mouse placental cell lines and early gestation human placenta for expression of FGF ligands. Expression in mouse TS cells was compared with preimplantation embryos, and human placental cell line expression was compared with human placenta, to infer which ligands are expressed in placental lineage vs. other cell lineages. The data suggest that human and mouse placenta share FGF18 and its high expression suggests preimplantation and early placental function.
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Affiliation(s)
- W Zhong
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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198
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Abstract
Fibroblast growth factor 23 (FGF23) is a circulating factor that plays critical roles in phosphate and vitamin D metabolism, as evidenced by the fact that FGF23 missense mutations cause autosomal dominant hypophosphatemic rickets (ADHR). Autosomal dominant hypophosphatemic rickets is characterized by hypophosphatemia with inappropriately normal 1,25-dihydroxyvitamin D concentrations, as well as bone pain, fracture and rickets. This phenotype parallels that of patients with tumor induced osteomalacia (TIO), X-linked hypophosphatemic rickets (XLH), and fibrous dysplasia (FD), in whom elevated serum FGF23 levels are often observed. The fibroblast growth factor receptors (FGFR1-4) play key roles in skeletal development, as well as in normal metabolic processes. Several FGFR isoforms that potentially mediate the activity of FGF23 have been implicated. In the short term, these findings will lead to further understanding of FGF23 function, and potentially in the long term, to targeted therapies in disorders of hypo- and hyperphosphatemia that involve FGF23.
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Affiliation(s)
- Xijie Yu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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199
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Dessimoz J, Opoka R, Kordich JJ, Grapin-Botton A, Wells JM. FGF signaling is necessary for establishing gut tube domains along the anterior-posterior axis in vivo. Mech Dev 2005; 123:42-55. [PMID: 16326079 DOI: 10.1016/j.mod.2005.10.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 10/11/2005] [Accepted: 10/12/2005] [Indexed: 01/25/2023]
Abstract
At the end of gastrulation in avians and mammals, the endoderm germ layer is an undetermined sheet of cells. Over the next 24-48 h, endoderm forms a primitive tube and becomes regionally specified along the anterior-posterior axis. Fgf4 is expressed in gastrulation and somite stage embryos in the vicinity of posterior endoderm that gives rise to the posterior gut. Moreover, the posterior endoderm adjacent to Fgf4-expressing mesoderm expresses the FGF-target genes Sprouty1 and 2 suggesting that endoderm respond to an FGF signal in vivo. Here, we report the first evidence suggesting that FGF4-mediated signaling is required for establishing gut tube domains along the A-P axis in vivo. At the gastrula stage, exposing endoderm to recombinant FGF4 protein results in an anterior shift in the Pdx1 and CdxB expression domains. These expression domains remain sensitive to FGF4 levels throughout early somite stages. Additionally, FGF4 represses the anterior endoderm markers Hex1 and Nkx2.1 and disrupts foregut morphogenesis. FGF signaling directly patterns endoderm and not via a secondary induction from another germ layer, as shown by expression of dominant-active FGFR1 specifically in endoderm, which results in ectopic anterior expression of Pdx1. Loss-of-function studies using the FGF receptor antagonist SU5402 demonstrate that FGF signaling is necessary for establishing midgut gene expression and for maintaining gene expression boundaries between the midgut and hindgut from gastrulation through somitogenesis. Moreover, FGF signaling in the primitive streak is necessary to restrict Hex1 expression to anterior endoderm. These data show that FGF signaling is critical for patterning the gut tube by promoting posterior and inhibiting anterior endoderm cell fate.
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Affiliation(s)
- Jessica Dessimoz
- ISREC, Chemin des Boveresses 155, CH1066, Epalinges/Lausanne, Switzerland
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200
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Bonaventure J, Silve C. Dysplasies osseuses héréditaires et voies de signalisation associées aux récepteurs FGFR3 et PTHR1. Med Sci (Paris) 2005; 21:954-61. [PMID: 16274647 DOI: 10.1051/medsci/20052111954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Skeletal development is a highly sophisticated process involving, as a first step, migration and condensation of mesenchymal cells into osteoprogenitor cells. These cells further differentiate into chondrocytes and osteoblasts through multiple differentiation stages requiring a set of specific transcriptional factors. Defective endochondral ossification in human is associated with a large number of inherited skeletal dysplasias caused by mutations in genes encoding extracellular matrix components, growth factors and their receptors, signaling molecules and transcription factors. This review summarizes some of the recent findings on a series of chondrodysplasias caused by mutations in FGFR3 and PTHR1, two receptors expressed in the cartilage growth plate and mediating two main signaling pathways. Data from human diseases and relevant animal models provide new clues for understanding how signaling molecules and their interaction with key transcription factors control and regulate the development and growth of long bones.
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MESH Headings
- Animals
- Cell Differentiation/genetics
- Cell Differentiation/physiology
- Chondrogenesis/genetics
- Chondrogenesis/physiology
- Fibroblast Growth Factor 3/physiology
- Growth Plate/pathology
- Humans
- Mesoderm/cytology
- Models, Animal
- Models, Genetic
- Mutation
- Osteochondrodysplasias/genetics
- Osteochondrodysplasias/physiopathology
- Osteogenesis/genetics
- Osteogenesis/physiology
- Parathyroid Hormone/physiology
- Receptor, Fibroblast Growth Factor, Type 3/deficiency
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/physiology
- Receptor, Parathyroid Hormone, Type 1
- Receptors, Parathyroid Hormone/deficiency
- Receptors, Parathyroid Hormone/genetics
- Receptors, Parathyroid Hormone/physiology
- Signal Transduction/genetics
- Signal Transduction/physiology
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Affiliation(s)
- Jacky Bonaventure
- CNRS UMR 146, Institut Curie, Bâtiment 110, Centre Universitaire Paris Sud, 91405 Orsay, France
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