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Pei W, Feldman B. Identification of common and unique modifiers of zebrafish midline bifurcation and cyclopia. Dev Biol 2008; 326:201-11. [PMID: 19046963 DOI: 10.1016/j.ydbio.2008.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 11/10/2008] [Accepted: 11/10/2008] [Indexed: 01/26/2023]
Abstract
Loss of the zebrafish Nodal-related protein Squint causes a spectrum of phenotypes including cyclopia and midline bifurcations (MB). Here we examine MBs and their relation to cyclopia in maternal-zygotic squint (MZsqt) mutants. There is a concordance of MB with cyclopia in MZsqt embryos. Heat treatment and depletion of Hsp90a are "common" risk factors, each of which increases the incidence of both phenotypes. Midline identity is specified on both sides of MBs, and deep-layer cells are initially lacking within bifurcations, whereas enveloping layer cells are intact. Bifurcations do not appear until the completion of gastrulation and are preceded by gaps in the expression of wnt5b, an essential regulator of dorsal convergence. The incidence of early MBs and wnt5b expression defects in heated MZsqt embryos is high, but there is also substantial recovery. Wnt5b depletion increases the incidence of MB, but not cyclopia, and as such Wnt5b is a "unique" risk factor for MB. Reciprocally, depletion of Wnt11 or Hsp90b increases cyclopia only. In summary, we find that MB arises after gastrulation in regions that fail to express wnt5b, and we show that two complex dysmorphologies - MB and cyclopia - can be promoted by either common or unique risk factors.
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Affiliation(s)
- Wuhong Pei
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 9000 Rockville Pike, Building 35, Room 1B 205, Bethesda, MD 20892, USA
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2
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Schiffer NW, Broadley SA, Hirschberger T, Tavan P, Kretzschmar HA, Giese A, Haass C, Hartl FU, Schmid B. Identification of anti-prion compounds as efficient inhibitors of polyglutamine protein aggregation in a zebrafish model. J Biol Chem 2006; 282:9195-203. [PMID: 17170113 DOI: 10.1074/jbc.m607865200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several neurodegenerative diseases, including Huntington disease (HD), are associated with aberrant folding and aggregation of polyglutamine (polyQ) expansion proteins. Here we established the zebrafish, Danio rerio, as a vertebrate HD model permitting the screening for chemical suppressors of polyQ aggregation and toxicity. Upon expression in zebrafish embryos, polyQ-expanded fragments of huntingtin (htt) accumulated in large SDS-insoluble inclusions, reproducing a key feature of HD pathology. Real time monitoring of inclusion formation in the living zebrafish indicated that inclusions grow by rapid incorporation of soluble htt species. Expression of mutant htt increased the frequency of embryos with abnormal morphology and the occurrence of apoptosis. Strikingly, apoptotic cells were largely devoid of visible aggregates, suggesting that soluble oligomeric precursors may instead be responsible for toxicity. As in nonvertebrate polyQ disease models, the molecular chaperones, Hsp40 and Hsp70, suppressed both polyQ aggregation and toxicity. Using the newly established zebrafish model, two compounds of the N'-benzylidene-benzohydrazide class directed against mammalian prion proved to be potent inhibitors of polyQ aggregation, consistent with a common structural mechanism of aggregation for prion and polyQ disease proteins.
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Affiliation(s)
- Niclas W Schiffer
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
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3
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Seidahmed MZ, Shaheed MM, Abdulbasit OB, Al Dohami H, Babiker M, Abdullah MA, Abomelha AM. A case of methotrexate embryopathy with holoprosencephaly, expanding the phenotype. ACTA ACUST UNITED AC 2006; 76:138-42. [PMID: 16470853 DOI: 10.1002/bdra.20199] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Methotrexate (MTX) embryopathy was described nearly 50 years ago, when this agent began to be used as a cancer treatment and abortifacient. In this report we describe a case with typical features of MTX syndrome together with new features to expand the phenotype. CASE A 29-year-old woman decided to terminate her unwanted pregnancy because of ill health, as she had conceived soon after her last delivery by cesarian section. At 6 weeks of gestation, she took 2.5 mg of MTX 3 times a day for 7 days. The pregnancy termination failed, and the pregnancy was carried to term. A female infant was delivered who was growth retarded and had characteristic features of MTX embryopathy in addition to holoprosencephaly and other brain malformations, facial hypertrichosis, and long eyelashes--features that have not hitherto been described. CONCLUSIONS We report the first case of holoprosencephaly in association with MTX exposure during the first 6 weeks of gestation. Physicians and the public should be aware of the effects of MTX on the fetus during pregnancy.
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4
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Wolf G. The function of cholesterol in embryogenesis. J Nutr Biochem 2005; 10:188-92. [PMID: 15539288 DOI: 10.1016/s0955-2863(98)00102-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/1998] [Accepted: 12/08/1998] [Indexed: 11/20/2022]
Abstract
Cholesterol is critical in embryonic development. Inhibition of cholesterol synthesis in experimental animals has caused a birth defect called holoprosencephaly (HPE), which is evidenced by cyclopia (one eye in the middle of the face), monorhinia (protruding single nose above the eye), absence of the pituitary gland, and central nervous system (CNS) abnormalities. In humans, an inherited defect in the cholesterol-synthesizing enzyme 7-dehydrocholesterol reductase depletes cholesterol and results in human HPE, termed Smith-Lemli-Opitz syndrome. In its most severe form, the syndrome leads to cyclopia, monorhinia, and lack of separation of cerebral hemispheres. The cause of the syndrome is a defect in a protein coded by the gene Sonic hedgehog (SHH). The protein SHH is expressed in the notochord of the CNS in the early embryo and is activated by being cleaved autocatalytically, with simultaneous covalent attachment of cholesterol to the N-terminal fragment, which is secreted by cells of the mesoderm layer, signaling the establishment of the neural midline cells. Thus, cholesterol is essential for proper signaling in the development of the normal embryo.
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Affiliation(s)
- G Wolf
- Department of Nutritional Sciences, University of California, Berkeley, CA 94720, USA
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Carvan MJ, Loucks E, Weber DN, Williams FE. Ethanol effects on the developing zebrafish: neurobehavior and skeletal morphogenesis. Neurotoxicol Teratol 2005; 26:757-68. [PMID: 15451040 DOI: 10.1016/j.ntt.2004.06.016] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Exposure to ethanol during development can lead to a constellation of congenital anomalies, resulting in prenatal and postnatal failure to thrive, central nervous system (CNS) deficits, and a number of patterning defects that lead to defects in the cardiovascular system, facial structures, and limbs. The cellular, biochemical, and molecular mechanisms by which ethanol exerts its developmental toxicity and the genes that influence sensitivity to developmental ethanol exposure have yet to be discovered, despite being one of the more common nongenetic causes of birth defects. The zebrafish undergoes much the same patterning and morphogenesis as other vertebrate embryos do--including humans--that are distinct and cannot be studied in invertebrates. Developmental processes in zebrafish are affected by ethanol exposure in a dose-dependent manner, resulting in learning and memory deficits, cell death in the CNS, skeletal dysmorphogenesis, and alterations in startle reflex responses. Interestingly, significant ethanol effects on learning and behavioral endpoints occurred at concentrations well below those that induced cell death in the CNS. This work provides the foundation for identifying genes and pathways involved in developmental alcohol toxicity in vertebrates, leading to a more complete mechanistic understanding of fetal alcohol disorders in humans.
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MESH Headings
- Alcohol-Induced Disorders, Nervous System/pathology
- Alcohol-Induced Disorders, Nervous System/physiopathology
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Bone and Bones/abnormalities
- Bone and Bones/drug effects
- Cell Death/drug effects
- Cell Death/genetics
- Craniofacial Abnormalities/chemically induced
- Craniofacial Abnormalities/pathology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Embryo, Nonmammalian/abnormalities
- Embryo, Nonmammalian/drug effects
- Ethanol/toxicity
- Larva/drug effects
- Larva/growth & development
- Learning Disabilities/chemically induced
- Learning Disabilities/physiopathology
- Memory Disorders/chemically induced
- Memory Disorders/physiopathology
- Reflex, Startle/drug effects
- Reflex, Startle/genetics
- Zebrafish/abnormalities
- Zebrafish/growth & development
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Affiliation(s)
- Michael J Carvan
- Great Lakes WATER Institute, University of Wisconsin-Milwaukee, 600 E. Greenfield Avenue, Milwaukee, WI 53204, USA.
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Yan YL, Willoughby J, Liu D, Crump JG, Wilson C, Miller CT, Singer A, Kimmel C, Westerfield M, Postlethwait JH. A pair of Sox: distinct and overlapping functions of zebrafish sox9 co-orthologs in craniofacial and pectoral fin development. Development 2005; 132:1069-83. [PMID: 15689370 DOI: 10.1242/dev.01674] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Understanding how developmental systems evolve after genome amplification is important for discerning the origins of vertebrate novelties, including neural crest, placodes, cartilage and bone. Sox9 is important for the development of these features, and zebrafish has two co-orthologs of tetrapod SOX9 stemming from an ancient genome duplication event in the lineage of ray-fin fish. We have used a genotype-driven screen to isolate a mutation deleting sox9b function, and investigated its phenotype and genetic interactions with a sox9a null mutation. Analysis of mutant phenotypes strongly supports the interpretation that ancestral gene functions partitioned spatially and temporally between Sox9 co-orthologs. Distinct subsets of the craniofacial skeleton, otic placode and pectoral appendage express each gene, and are defective in each single mutant. The double mutant phenotype is additive or synergistic. Ears are somewhat reduced in each single mutant but are mostly absent in the double mutant. Loss-of-function animals from mutations and morpholino injections, and gain-of-function animals injected with sox9a and sox9b mRNAs showed that sox9 helps regulate other early crest genes, including foxd3, sox10, snai1b and crestin, as well as the cartilage gene col2a1 and the bone gene runx2a; however, tfap2a was nearly unchanged in mutants. Chondrocytes failed to stack in sox9a mutants, failed to attain proper numbers in sox9b mutants and failed in both morphogenetic processes in double mutants. Pleiotropy can cause mutations in single copy tetrapod genes, such as Sox9, to block development early and obscure later gene functions. By contrast, subfunction partitioning between zebrafish co-orthologs of tetrapod genes, such as sox9a and sox9b, can relax pleiotropy and reveal both early and late developmental gene functions.
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Affiliation(s)
- Yi-Lin Yan
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
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7
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Haffner C, Haass C. The Biochemical and Genetic Odyssey to the Function of a Nicastrin-Like Protein. NEURODEGENER DIS 2004; 1:192-5. [PMID: 16908989 DOI: 10.1159/000080985] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Gamma-secretase is a high-molecular-weight protein complex required for the proteolytic processing of various transmembrane proteins including the Alzheimer's disease-associated amyloid precursor protein and the signaling receptor Notch. One of the gamma-secretase complex components is the type I transmembrane protein nicastrin. Here we review the odyssey to a cyclopic fish, which at the end allowed the functional analysis of nicalin, a novel member of the nicastrin protein family. This 60-kDa protein is part of a previously unknown membrane protein complex unrelated to gamma-secretase and binds to Nomo (Nodal modulator, previously known as pM5), a novel 130-kDa transmembrane protein. Both proteins are highly conserved in metazoans and show almost identical tissue distribution in humans. Functional studies in zebrafish embryos and cultured human cells revealed that nicalin and Nomo collaborate to antagonize the Nodal/TGFbeta signaling pathway. Thus, nicastrin and nicalin are both associated with protein complexes involved in cell fate decisions during early embryonic development.
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Affiliation(s)
- Christof Haffner
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf Butenandt Institute, Ludwig Maximilians University, Munich, Germany.
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Postlethwait J, Amores A, Cresko W, Singer A, Yan YL. Subfunction partitioning, the teleost radiation and the annotation of the human genome. Trends Genet 2004; 20:481-90. [PMID: 15363902 DOI: 10.1016/j.tig.2004.08.001] [Citation(s) in RCA: 334] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Half of all vertebrate species are teleost fish. What accounts for this explosion of biodiversity? Recent evidence and advances in evolutionary theory suggest that genomic features could have played a significant role in the teleost radiation. This review examines evidence for an ancient whole-genome duplication (tetraploidization) event that probably occurred just before the teleost radiation. The partitioning of ancestral subfunctions between gene copies arising from this duplication could have contributed to the genetic isolation of populations, to lineage-specific diversification of developmental programs, and ultimately to phenotypic variation among teleost fish. Beyond its importance for understanding mechanisms that generate biodiversity, the partitioning of subfunctions between teleost co-orthologs of human genes can facilitate the identification of tissue-specific conserved noncoding regions and can simplify the analysis of ancestral gene functions obscured by pleiotropy or haploinsufficiency. Applying these principles on a genomic scale can accelerate the functional annotation of the human genome and understanding of the roles of human genes in health and disease.
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Affiliation(s)
- John Postlethwait
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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Haffner C, Frauli M, Topp S, Irmler M, Hofmann K, Regula JT, Bally-Cuif L, Haass C. Nicalin and its binding partner Nomo are novel Nodal signaling antagonists. EMBO J 2004; 23:3041-50. [PMID: 15257293 PMCID: PMC514924 DOI: 10.1038/sj.emboj.7600307] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Accepted: 06/08/2004] [Indexed: 12/20/2022] Open
Abstract
Nodals are signaling factors of the transforming growth factor-beta (TGFbeta) superfamily with a key role in vertebrate development. They control a variety of cell fate decisions required for the establishment of the embryonic body plan. We have identified two highly conserved transmembrane proteins, Nicalin and Nomo (Nodal modulator, previously known as pM5), as novel antagonists of Nodal signaling. Nicalin is distantly related to Nicastrin, a component of the Alzheimer's disease-associated gamma-secretase, and forms a complex with Nomo. Ectopic expression of both proteins in zebrafish embryos causes cyclopia, a phenotype that can arise from a defect in mesendoderm patterning mediated by the Nodal signaling pathway. Accordingly, downregulation of Nomo resulted in an increase in anterior axial mesendoderm and the development of an enlarged hatching gland. Inhibition of Nodal signaling by ectopic expression of Lefty was rescued by reducing Nomo levels. Furthermore, Nodal- as well as Activin-induced signaling was inhibited by Nicalin and Nomo in a cell-based reporter assay. Our data demonstrate that the Nicalin/Nomo complex antagonizes Nodal signaling during mesendodermal patterning in zebrafish.
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Affiliation(s)
- Christof Haffner
- Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Adolf-Butenandt-Institute, Ludwig-Maximilians-University, Munich, Germany
- Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Adolf-Butenandt-Institute, Ludwig-Maximilians-University, Schillerstr. 44, 80336 Munich, Germany. Tel.: +49 89 5996 484; Fax: +49 89 5996 415; E-mail:
| | - Mélanie Frauli
- Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Adolf-Butenandt-Institute, Ludwig-Maximilians-University, Munich, Germany
| | - Stephanie Topp
- Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Adolf-Butenandt-Institute, Ludwig-Maximilians-University, Munich, Germany
- Zebrafish Neurogenetics Research Group, Department of Virology, Technical University-Munich, Munich, Germany
- GSF-National Research Center for Environment and Health, Institute of Developmental Genetics, Neuherberg, Germany
| | - Martin Irmler
- Bioinformatics Group, MEMOREC Biotech GmbH, Cologne, Germany
| | - Kay Hofmann
- Bioinformatics Group, MEMOREC Biotech GmbH, Cologne, Germany
| | - Jörg T Regula
- Adolf-Butenandt-Institute, Protein Analysis Unit, Ludwig-Maximilians-University, Munich, Germany
| | - Laure Bally-Cuif
- Zebrafish Neurogenetics Research Group, Department of Virology, Technical University-Munich, Munich, Germany
- GSF-National Research Center for Environment and Health, Institute of Developmental Genetics, Neuherberg, Germany
| | - Christian Haass
- Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Adolf-Butenandt-Institute, Ludwig-Maximilians-University, Munich, Germany
- Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Adolf-Butenandt-Institute, Ludwig-Maximilians-University, Schillerstr. 44, 80336 Munich, Germany. Tel.: +49 89 5996 474; Fax: +49 89 5996 415; E-mail:
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10
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Watanabe M, Rebbert ML, Andreazzoli M, Takahashi N, Toyama R, Zimmerman S, Whitman M, Dawid IB. Regulation of the Lim-1 gene is mediated through conserved FAST-1/FoxH1 sites in the first intron. Dev Dyn 2002; 225:448-56. [PMID: 12454922 DOI: 10.1002/dvdy.10176] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Lim-1 gene encodes a LIM-homeodomain transcription factor that is highly conserved among vertebrates and is required for successful gastrulation and head formation. The expression of this gene in the mesoderm of the gastrula is known to require an activin/nodal signal. Earlier studies have shown that the Xenopus Lim-1 (Xlim-1) gene contains an activin response element (ARE) in its first intron, which cooperates with an activin-unresponsive upstream promoter in the regulation of the gene. Here, we show that the Xlim-1 ARE contains a cluster of FAST-1/FoxH1 and Smad4 recognition sites; such sites have been shown to mediate activin/nodal responses in other genes. By using reporter constructs with mutated FAST-1/FoxH1 sites and FAST-1/FoxH1 protein chimeras, we show that the regulation of Xlim-1 by activin depends on FAST-1/FoxH1 function. Comparative studies on the zebrafish lim1 gene indicate the presence of FoxH1 sites in the first intron of this gene and provide evidence for the requirement for FoxH1 function in its regulation. These results illuminate the conserved nature of the transcriptional regulation of the Lim-1 gene in different vertebrate animals.
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Affiliation(s)
- Minoru Watanabe
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
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11
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Ming JE, Muenke M. Multiple hits during early embryonic development: digenic diseases and holoprosencephaly. Am J Hum Genet 2002; 71:1017-32. [PMID: 12395298 PMCID: PMC385082 DOI: 10.1086/344412] [Citation(s) in RCA: 258] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2002] [Accepted: 08/20/2002] [Indexed: 01/16/2023] Open
Affiliation(s)
- Jeffrey E. Ming
- Division of Human Genetics and Molecular Biology, Department of Pediatrics, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia; and Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda
| | - Maximilian Muenke
- Division of Human Genetics and Molecular Biology, Department of Pediatrics, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia; and Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda
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12
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Shanmugalingam S, Houart C, Picker A, Reifers F, Macdonald R, Barth A, Griffin K, Brand M, Wilson SW. Ace/Fgf8 is required for forebrain commissure formation and patterning of the telencephalon. Development 2000; 127:2549-61. [PMID: 10821754 DOI: 10.1242/dev.127.12.2549] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fibroblast growth factors (Fgfs) form a large family of secreted signalling proteins that have a wide variety of roles during embryonic development. Within the central nervous system (CNS) Fgf8 is implicated in patterning neural tissue adjacent to the midbrain-hindbrain boundary. However, the roles of Fgfs in CNS tissue rostral to the midbrain are less clear. Here we examine the patterning of the forebrain in zebrafish embryos that lack functional Fgf8/Ace. We find that Ace is required for the development of midline structures in the forebrain. In the absence of Ace activity, midline cells fail to adopt their normal morphology and exhibit altered patterns of gene expression. This disruption to midline tissue leads to severe commissural axon pathway defects, including misprojections from the eye to ectopic ipsilateral and contralateral targets. Ace is also required for the differentiation of the basal telencephalon and several populations of putative telencephalic neurons but not for overall regional patterning of forebrain derivatives. Finally, we show that ace expression co-localises with anterior neural plate cells that have previously been shown to have forebrain patterning activity. Removal of these cells leads to a failure in induction of ace expression indicating that loss of Ace activity may contribute to the phenotypes observed when anterior neural plate cells are ablated. However, as ace mutant neural plate cells still retain at least some inductive activity, then other signals must also be produced by the anterior margin of the neural plate.
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Affiliation(s)
- S Shanmugalingam
- Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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