Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
In the vertebrate eye, the retinal pigment epithelium (RPE) and the neural retina arise from a single layer of neuroectoderm. Factors influencing the differentiation of retinal neurons have been identified; however, little is known about molecules directing the differentiation of the RPE. Here we have found that the neurotrophin brain-derived neurotrophic factor (BDNF) plays an autocrine role in the differentiation and survival of Xenopus laevis RPE. Fluorescent in situ hybridization studies showed a precise co-expression of BDNF and its receptor trkB in the retinal neuroepithelium and actively differentiating RPE; in vitro studies demonstrated survival- and differentiation-promoting effects in serum-free explants and dissociated cultures. When a dominant negative mutant of the trkB receptor was expressed in developing embryos, severe arrest of RPE differentiation was seen with persistence of nestin- and Notch-positive neuroblasts.
Fig. 1.
Co-Localization of Notch, TrkB, and BDNF in the developing optic cup. Top panels, FISH of stage 26 Xenopus optic cups (sagittal sections, en face). In A–C, a single section was probed with cRNA antisense probes incorporating fluorescein-12-UTP (Boeringer Mannheim) for Xenopus Notch (A) or TMR-5-UTP (Molecular Probes) fluorescein isothiocianate for the kinase-containing domain of Xenopus trkB (B) andNotch plus trkB (C). D–F, FISH of stage 28 retinas (coronal sections) probed with FITC antisense riboprobes for trkB (D), RITC probes for BDNF (E), and FITC-trkB plus RITC-BDNF (F). G–J, en face views of stage 30 Xenopus retinas probed with FITC-trkB (G), RITC-BDNF (H), FITC-trkB plus RITC-BDNF (I), and FITCNotch (J). K, Bright-field exposure of a stage 32 Xenopus retina probed with FITC-trkB (L). M, Bright-field exposure of a stage 32 Xenopus retina probed with FITC-Notch (N). Scale bar, 0.1 mm.
Fig. 2.
BDNF-blocking antibody prevents RPE differentiation in vitro. A–C, Representative control stage 26 explant at days 1, 3, and 5 after plating. D–F, Representative explant cultured in the presence of 15 μg/ml BDNF antibody at days 1, 3, and 5.G–I, Represented explant cultured in the presence of 50 μg/ml BDNF antibody.
Fig. 3.
BDNF promotes RPE survival. The survival rates of dissociated RPE in the presence (black squares) or absence (white circles) of 100 ng/ml BDNF are shown.Points represent the average of eight wells. Error bars indicate SD.
Fig. 4.
Expression of the Myc-tagged TrkB mutant.A, Whole-mount immunohistochemistry of stage 32 embryos using an anti-myc antibody (9E10). At left is an embryo injected with sterile water, at right, three mutants expressing the myc-tagged trkB mutant. Scale bar, 0.1 mm.B, Immunofluorescent staining (using the 9E10 antibody) of the eyes of stage 26 embryos injected either with water (WT) or cRNA encoding the trkB mutant (TrkBMut). Scale bar, 10 μm. C, Western blot of stage 26 embryo lysates injected with either sterile water (WT) or cRNA encoding the myc-tagged trkB mutant (TrkBMut). A band at 145 kDa corresponds to the mutant trkB receptor.
ig. 5.
Retinal pigment abnormalities in dominant negative TrkB mutants. Representative photographs of the eyes of water-injected controls (A) and the trkB dominant negative mutants (B, C). D–F, Representative sections from the central retinas of cresyl violet–eosin-stained tissues. Embryos were generated simultaneously and killed at stage 45. A water-injected embryo is shown in D; mildly and severely affected embryos are seen in E and F, respectively. Scale bar, 50 μm. G, H, Immunofluorescent sections from a stage 45 water-injected control embryo (G) or mildly affected mutant (H) probed with a polyclonal antibody to CRALBP (Bunt-Milam and Saari, 1983). Arrows indicate the RPE layer. I,J, Immunofluorescent sections from stage 45 water-injected controls (I) or a severely affected mutant (J). Sections were probed with a polyclonal antibody raised against the intermediate filament nestin (Tohyama et al., 1992). K, L, Sections from a stage 45 water-injected control (K) or severely affected trkB mutant (L) probed with RITC antisense riboprobe for Xenopus Notch. Scale bar, 0.1 mm.
Artavanis-Tsakonas,
The Notch locus and the cell biology of neuroblast segregation.
1991, Pubmed
Artavanis-Tsakonas,
The Notch locus and the cell biology of neuroblast segregation.
1991,
Pubmed Austin,
Vertebrate retinal ganglion cells are selected from competent progenitors by the action of Notch.
1995,
Pubmed Bok,
The retinal pigment epithelium: a versatile partner in vision.
1993,
Pubmed Bovolenta,
Neurotrophin-3 antibodies disrupt the normal development of the chick retina.
1996,
Pubmed Brill,
Epithelial-mesenchymal conversion of dermatome progenitors requires neural tube-derived signals: characterization of the role of Neurotrophin-3.
1995,
Pubmed Bunt-Milam,
Immunocytochemical localization of two retinoid-binding proteins in vertebrate retina.
1983,
Pubmed
,
Xenbase Cepko,
Cell fate determination in the vertebrate retina.
1996,
Pubmed Coffman,
Xotch, the Xenopus homolog of Drosophila notch.
1990,
Pubmed
,
Xenbase Cohen-Cory,
BDNF in the development of the visual system of Xenopus.
1994,
Pubmed
,
Xenbase Cohen-Cory,
The cellular patterns of BDNF and trkB expression suggest multiple roles for BDNF during Xenopus visual system development.
1996,
Pubmed
,
Xenbase Conover,
Neuronal deficits, not involving motor neurons, in mice lacking BDNF and/or NT4.
1995,
Pubmed Defoe,
Reattachment of retinas to cultured pigment epithelial monolayers from Xenopus laevis.
1994,
Pubmed
,
Xenbase Dorsky,
Xotch inhibits cell differentiation in the Xenopus retina.
1995,
Pubmed
,
Xenbase Eide,
Neurotrophins and their receptors--current concepts and implications for neurologic disease.
1993,
Pubmed
,
Xenbase Eide,
Naturally occurring truncated trkB receptors have dominant inhibitory effects on brain-derived neurotrophic factor signaling.
1996,
Pubmed
,
Xenbase Evan,
Isolation of monoclonal antibodies specific for human c-myc proto-oncogene product.
1985,
Pubmed
,
Xenbase Frade,
Insulin-like growth factor-I stimulates neurogenesis in chick retina by regulating expression of the alpha 6 integrin subunit.
1996,
Pubmed Hallböök,
Cellular localization of brain-derived neurotrophic factor and neurotrophin-3 mRNA expression in the early chicken embryo.
1993,
Pubmed Harris,
Two cellular inductions involved in photoreceptor determination in the Xenopus retina.
1992,
Pubmed
,
Xenbase Heitzler,
The choice of cell fate in the epidermis of Drosophila.
1991,
Pubmed Hyman,
Overlapping and distinct actions of the neurotrophins BDNF, NT-3, and NT-4/5 on cultured dopaminergic and GABAergic neurons of the ventral mesencephalon.
1994,
Pubmed Jones,
Targeted disruption of the BDNF gene perturbs brain and sensory neuron development but not motor neuron development.
1994,
Pubmed Kelley,
Retinoic acid promotes differentiation of photoreceptors in vitro.
1994,
Pubmed Klein,
Targeted disruption of the trkB neurotrophin receptor gene results in nervous system lesions and neonatal death.
1993,
Pubmed Koide,
Localization of trkB and low-affinity nerve growth factor receptor mRNA in the developing rat retina.
1995,
Pubmed Krieg,
Functional messenger RNAs are produced by SP6 in vitro transcription of cloned cDNAs.
1984,
Pubmed
,
Xenbase Laemmli,
Cleavage of structural proteins during the assembly of the head of bacteriophage T4.
1970,
Pubmed Langtimm-Sedlak,
Multiple actions of stem cell factor in neural crest cell differentiation in vitro.
1996,
Pubmed LaVail,
Multiple growth factors, cytokines, and neurotrophins rescue photoreceptors from the damaging effects of constant light.
1992,
Pubmed MacNicol,
Raf-1 kinase is essential for early Xenopus development and mediates the induction of mesoderm by FGF.
1993,
Pubmed
,
Xenbase Mitsiadis,
Neurotrophins in odontogenesis.
1995,
Pubmed Niman,
Generation of protein-reactive antibodies by short peptides is an event of high frequency: implications for the structural basis of immune recognition.
1983,
Pubmed Okazawa,
Gene regulation of trkB and trkC in the chick retina by light/darkness exposure.
1994,
Pubmed O'Keefe,
In situ hyridization.
1991,
Pubmed
,
Xenbase Park,
Growth factor-induced retinal regeneration in vivo.
1993,
Pubmed Perez,
Expression of brain-derived neurotrophic factor and of its functional receptor in neonatal and adult rat retina.
1995,
Pubmed Pérez,
Light-induced retinopathy in the albino rat in long-term studies. An immunohistochemical and quantitative approach.
1994,
Pubmed Pittack,
Basic fibroblast growth factor induces retinal pigment epithelium to generate neural retina in vitro.
1991,
Pubmed Raymond,
The retinal pigmented epithelium is required for development and maintenance of the mouse neural retina.
1995,
Pubmed Sklair-Tavron,
Opposing effects of morphine and the neurotrophins, NT-3, NT-4, and BDNF, on locus coeruleus neurons in vitro.
1995,
Pubmed Szczesny,
Light damage in rod outer segments: the effects of fixation on ultrastructural alterations.
1996,
Pubmed Tohyama,
Nestin expression in embryonic human neuroepithelium and in human neuroepithelial tumor cells.
1992,
Pubmed Tomita,
Mammalian hairy and Enhancer of split homolog 1 regulates differentiation of retinal neurons and is essential for eye morphogenesis.
1996,
Pubmed Ugolini,
TrkA, TrkB and p75 mRNA expression is developmentally regulated in the rat retina.
1995,
Pubmed Unoki,
Protection of the rat retina from ischemic injury by brain-derived neurotrophic factor, ciliary neurotrophic factor, and basic fibroblast growth factor.
1994,
Pubmed Vize,
Assays for gene function in developing Xenopus embryos.
1991,
Pubmed
,
Xenbase Wheeler,
Spatiotemporal patterns of expression of NGF and the low-affinity NGF receptor in rat embryos suggest functional roles in tissue morphogenesis and myogenesis.
1992,
Pubmed
