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1.
Development ; 148(13)2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34104942

RESUMO

Epithelial cilia, whether motile or primary, often display an off-center planar localization within the apical cell surface. This form of planar cell polarity (PCP) involves the asymmetric positioning of the ciliary basal body (BB). Using the monociliated epithelium of the embryonic zebrafish floor-plate, we investigated the dynamics and mechanisms of BB polarization by live imaging. BBs were highly motile, making back-and-forth movements along the antero-posterior (AP) axis and contacting both the anterior and posterior membranes. Contacts exclusively occurred at junctional Par3 patches and were often preceded by membrane digitations extending towards the BB, suggesting focused cortical pulling forces. Accordingly, BBs and Par3 patches were linked by dynamic microtubules. Later, BBs became less motile and eventually settled at posterior apical junctions enriched in Par3. BB posterior positioning followed Par3 posterior enrichment and was impaired upon Par3 depletion or disorganization of Par3 patches. In the PCP mutant vangl2, BBs were still motile but displayed poorly oriented membrane contacts that correlated with Par3 patch fragmentation and lateral spreading. Thus, we propose an unexpected function for posterior Par3 enrichment in controlling BB positioning downstream of the PCP pathway.


Assuntos
Corpos Basais/metabolismo , Proteínas de Transporte/metabolismo , Cílios/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Animais , Proteínas de Transporte/genética , Polaridade Celular , Feminino , Masculino , Proteínas de Membrana/metabolismo , Microtúbulos/metabolismo , Transcriptoma , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
2.
PLoS Biol ; 18(3): e3000640, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32163404

RESUMO

Ciliary shedding occurs from unicellular organisms to metazoans. Although required during the cell cycle and during neurogenesis, the process remains poorly understood. In all cellular models, this phenomenon occurs distal to the transition zone (TZ), suggesting conserved molecular mechanisms. The TZ module proteins (Meckel Gruber syndrome [MKS]/Nephronophtysis [NPHP]/Centrosomal protein of 290 kDa [CEP290]/Retinitis pigmentosa GTPase regulator-Interacting Protein 1-Like Protein [RPGRIP1L]) are known to cooperate to establish TZ formation and function. To determine whether they control deciliation, we studied the function of 5 of them (Transmembrane protein 107 [TMEM107], Transmembrane protein 216 [TMEM216], CEP290, RPGRIP1L, and NPHP4) in Paramecium. All proteins are recruited to the TZ of growing cilia and localize with 9-fold symmetry at the level of the most distal part of the TZ. We demonstrate that depletion of the MKS2/TMEM216 and TMEM107 proteins induces constant deciliation of some cilia, while depletion of either NPHP4, CEP290, or RPGRIP1L prevents Ca2+/EtOH deciliation. Our results constitute the first evidence for a role of conserved TZ proteins in deciliation and open new directions for understanding motile cilia physiology.


Assuntos
Cílios/metabolismo , Paramecium tetraurellia/citologia , Proteínas de Protozoários/metabolismo , Proliferação de Células , Cílios/fisiologia , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Expressão Gênica , Fusão de Membrana/genética , Paramecium tetraurellia/genética , Domínios Proteicos , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Interferência de RNA
3.
EMBO J ; 37(10)2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29650680

RESUMO

Ciliopathies are life-threatening human diseases caused by defective cilia. They can often be traced back to mutations of genes encoding transition zone (TZ) proteins demonstrating that the understanding of TZ organisation is of paramount importance. The TZ consists of multimeric protein modules that are subject to a stringent assembly hierarchy. Previous reports place Rpgrip1l at the top of the TZ assembly hierarchy in Caenorhabditis elegans By performing quantitative immunofluorescence studies in RPGRIP1L-/- mouse embryos and human embryonic cells, we recognise a different situation in vertebrates in which Rpgrip1l deficiency affects TZ assembly in a cell type-specific manner. In cell types in which the loss of Rpgrip1l alone does not affect all modules, additional truncation or removal of vertebrate-specific Rpgrip1 results in an impairment of all modules. Consequently, Rpgrip1l and Rpgrip1 synergistically ensure the TZ composition in several vertebrate cell types, revealing a higher complexity of TZ assembly in vertebrates than in invertebrates.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Cílios/fisiologia , Embrião de Mamíferos/metabolismo , Fibroblastos/metabolismo , Proteínas/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antígenos de Neoplasias , Proteínas de Transporte/fisiologia , Proteínas de Ciclo Celular , Estruturas da Membrana Celular , Células Cultivadas , Proteínas do Citoesqueleto , Embrião de Mamíferos/citologia , Fibroblastos/citologia , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Nucleares/fisiologia , Fatores de Transcrição/fisiologia
4.
PLoS Genet ; 15(1): e1007914, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30689641

RESUMO

Cilia-related proteins are believed to be involved in a broad range of cellular processes. Retinitis pigmentosa GTPase regulator interacting protein 1-like (RPGRIP1L) is a ciliary protein required for ciliogenesis in many cell types, including epidermal keratinocytes. Here we report that RPGRIP1L is also involved in the maintenance of desmosomal junctions between keratinocytes. Genetically disrupting the Rpgrip1l gene in mice caused intraepidermal blistering, primarily between basal and suprabasal keratinocytes. This blistering phenotype was associated with aberrant expression patterns of desmosomal proteins, impaired desmosome ultrastructure, and compromised cell-cell adhesion in vivo and in vitro. We found that disrupting the RPGRIP1L gene in HaCaT cells, which do not form primary cilia, resulted in mislocalization of desmosomal proteins to the cytoplasm, suggesting a cilia-independent function of RPGRIP1L. Mechanistically, we found that RPGRIP1L regulates the endocytosis of desmogleins such that RPGRIP1L-knockdown not only induced spontaneous desmoglein endocytosis, as determined by AK23 labeling and biotinylation assays, but also exacerbated EGTA- or pemphigus vulgaris IgG-induced desmoglein endocytosis. Accordingly, inhibiting endocytosis with dynasore or sucrose rescued these desmosomal phenotypes. Biotinylation assays on cell surface proteins not only reinforced the role of RPGRIP1L in desmoglein endocytosis, but also suggested that RPGRIP1L may be more broadly involved in endocytosis. Thus, data obtained from this study advanced our understanding of the biological functions of RPGRIP1L by identifying its role in the cellular endocytic pathway.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Desmossomos/genética , Endocitose/genética , Animais , Adesão Celular/genética , Linhagem Celular , Desmogleínas/genética , Desmogleínas/metabolismo , Epiderme/metabolismo , Humanos , Junções Intercelulares/genética , Queratinócitos/metabolismo , Camundongos
5.
Neurobiol Dis ; 150: 105236, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33383187

RESUMO

Development of the forebrain critically depends on the Sonic Hedgehog (Shh) signaling pathway, as illustrated in humans by the frequent perturbation of this pathway in holoprosencephaly, a condition defined as a defect in the formation of midline structures of the forebrain and face. The Shh pathway requires functional primary cilia, microtubule-based organelles present on virtually every cell and acting as cellular antennae to receive and transduce diverse chemical, mechanical or light signals. The dysfunction of cilia in humans leads to inherited diseases called ciliopathies, which often affect many organs and show diverse manifestations including forebrain malformations for the most severe forms. The purpose of this review is to provide the reader with a framework to understand the developmental origin of the forebrain defects observed in severe ciliopathies with respect to perturbations of the Shh pathway. We propose that many of these defects can be interpreted as an imbalance in the ratio of activator to repressor forms of the Gli transcription factors, which are effectors of the Shh pathway. We also discuss the complexity of ciliopathies and their relationships with forebrain disorders such as holoprosencephaly or malformations of cortical development, and emphasize the need for a closer examination of forebrain defects in ciliopathies, not only through the lens of animal models but also taking advantage of the increasing potential of the research on human tissues and organoids.


Assuntos
Encéfalo/anormalidades , Cílios/genética , Ciliopatias/embriologia , Anormalidades Craniofaciais/embriologia , Proteínas Hedgehog/fisiologia , Prosencéfalo/embriologia , Anormalidades Múltiplas/embriologia , Anormalidades Múltiplas/genética , Encéfalo/embriologia , Cerebelo/anormalidades , Cerebelo/embriologia , Transtornos da Motilidade Ciliar/embriologia , Transtornos da Motilidade Ciliar/genética , Ciliopatias/genética , Anormalidades Craniofaciais/genética , Deficiências do Desenvolvimento/genética , Encefalocele/embriologia , Encefalocele/genética , Anormalidades do Olho/embriologia , Anormalidades do Olho/genética , Regulação da Expressão Gênica no Desenvolvimento , Holoprosencefalia/embriologia , Holoprosencefalia/genética , Humanos , Doenças Renais Císticas/embriologia , Doenças Renais Císticas/genética , Doenças Renais Policísticas/embriologia , Doenças Renais Policísticas/genética , Retina/anormalidades , Retina/embriologia , Retinose Pigmentar/embriologia , Retinose Pigmentar/genética , Transdução de Sinais , Proteína GLI1 em Dedos de Zinco/genética , Proteína Gli2 com Dedos de Zinco/genética , Proteína Gli3 com Dedos de Zinco/genética
6.
Genesis ; 58(1): e23340, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31571409

RESUMO

CRISPR/Cas9-based strategies are widely used for genome editing in many organisms, including zebrafish. Although most applications consist in introducing double strand break (DSB)-induced mutations, it is also possible to use CRISPR/Cas9 to enhance homology directed repair (HDR) at a chosen genomic location to create knock-ins with optimally controlled precision. Here, we describe the use of CRISPR/Cas9-targeted DSB followed by HDR to generate zebrafish transgenic lines where exogenous coding sequences are added in the nefma gene, in frame with the endogenous coding sequence. The resulting knock-in embryos express the added gene (fluorescent reporter or KalTA4 transactivator) specifically in the populations of neurons that express nefma, making them convenient tools for research on these populations.


Assuntos
Técnicas de Introdução de Genes/métodos , Engenharia Genética/métodos , Animais , Animais Geneticamente Modificados/genética , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , Marcação de Genes/métodos , Genoma/genética , Recombinação Homóloga/genética , Filamentos Intermediários/genética , RNA Guia de Cinetoplastídeos/genética , Peixe-Zebra/genética
7.
J Neurosci ; 39(13): 2398-2415, 2019 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-30692221

RESUMO

Primary cilia are essential for CNS development. In the mouse, they play a critical role in patterning the spinal cord and telencephalon via the regulation of Hedgehog/Gli signaling. However, despite the frequent disruption of this signaling pathway in human forebrain malformations, the role of primary cilia in forebrain morphogenesis has been little investigated outside the telencephalon. Here we studied development of the diencephalon, hypothalamus and eyes in mutant mice in which the Ftm/Rpgrip1l ciliopathy gene is disrupted. At the end of gestation, Ftm-/- fetuses displayed anophthalmia, a reduction of the ventral hypothalamus and a disorganization of diencephalic nuclei and axonal tracts. In Ftm-/- embryos, we found that the ventral forebrain structures and the rostral thalamus were missing. Optic vesicles formed but lacked the optic cups. In Ftm-/- embryos, Sonic hedgehog (Shh) expression was virtually lost in the ventral forebrain but maintained in the zona limitans intrathalamica (ZLI), the mid-diencephalic organizer. Gli activity was severely downregulated but not lost in the ventral forebrain and in regions adjacent to the Shh-expressing ZLI. Reintroduction of the repressor form of Gli3 into the Ftm-/- background restored optic cup formation. Our data thus uncover a complex role of cilia in development of the diencephalon, hypothalamus and eyes via the region-specific control of the ratio of activator and repressor forms of the Gli transcription factors. They call for a closer examination of forebrain defects in severe ciliopathies and for a search for ciliopathy genes as modifiers in other human conditions with forebrain defects.SIGNIFICANCE STATEMENT The Hedgehog (Hh) signaling pathway is essential for proper forebrain development as illustrated by a human condition called holoprosencephaly. The Hh pathway relies on primary cilia, cellular organelles that receive and transduce extracellular signals and whose dysfunctions lead to rare inherited diseases called ciliopathies. To date, the role of cilia in the forebrain has been poorly studied outside the telencephalon. In this paper we study the role of the Ftm/Rpgrip1l ciliopathy gene in mouse forebrain development. We uncover complex functions of primary cilia in forebrain morphogenesis through region-specific modulation of the Hh pathway. Our data call for further examination of forebrain defects in ciliopathies and for a search for ciliopathy genes as modifiers in human conditions affecting forebrain development.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Hedgehog/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Prosencéfalo/embriologia , Prosencéfalo/metabolismo , Proteína Gli3 com Dedos de Zinco/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Olho/embriologia , Olho/metabolismo , Hipotálamo/embriologia , Hipotálamo/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais , Tálamo/embriologia , Tálamo/metabolismo
8.
BMC Bioinformatics ; 20(1): 470, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31521111

RESUMO

BACKGROUND: Neurogenesis in the murine cerebral cortex involves the coordinated divisions of two main types of progenitor cells, whose numbers, division modes and cell cycle durations set up the final neuronal output. To understand the respective roles of these factors in the neurogenesis process, we combine experimental in vivo studies with mathematical modeling and numerical simulations of the dynamics of neural progenitor cells. A special focus is put on the population of intermediate progenitors (IPs), a transit amplifying progenitor type critically involved in the size of the final neuron pool. RESULTS: A multiscale formalism describing IP dynamics allows one to track the progression of cells along the subsequent phases of the cell cycle, as well as the temporal evolution of the different cell numbers. Our model takes into account the dividing apical progenitors (AP) engaged into neurogenesis, both neurogenic and proliferative IPs, and the newborn neurons. The transfer rates from one population to another are subject to the mode of division (proliferative, or neurogenic) and may be time-varying. The model outputs are successfully fitted to experimental cell numbers from mouse embryos at different stages of cortical development, taking into account IPs and neurons, in order to adjust the numerical parameters. We provide additional information on cell kinetics, such as the mitotic and S phase indexes, and neurogenic fraction. CONCLUSIONS: Applying the model to a mouse mutant for Ftm/Rpgrip1l, a gene involved in human ciliopathies with severe brain abnormalities, reveals a shortening of the neurogenic period associated with an increased influx of newborn IPs from apical progenitors at mid-neurogenesis. Our model can be used to study other mouse mutants with cortical neurogenesis defects and can be adapted to study the importance of progenitor dynamics in cortical evolution and human diseases.


Assuntos
Córtex Cerebral/crescimento & desenvolvimento , Modelos Biológicos , Neurogênese , Animais , Ciclo Celular , Divisão Celular , Córtex Cerebral/fisiopatologia , Proteínas do Citoesqueleto , Modelos Animais de Doenças , Humanos , Camundongos , Mutação , Células-Tronco Neurais/fisiologia , Neurônios/fisiologia , Proteínas/genética
9.
Biol Cell ; 110(6): 125-136, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29698566

RESUMO

Neuronal circuits, the functional building blocks of the nervous system, assemble during development through a series of dynamic processes including the migration of neurons to their final position, the growth and navigation of axons and their synaptic connection with target cells. While the role of chemical cues in guiding neuronal migration and axonal development has been extensively analysed, the contribution of mechanical inputs, such as forces and stiffness, has received far less attention. In this article, we review the in vitro and more recent in vivo studies supporting the notion that mechanical signals are critical for multiple aspects of neuronal circuit assembly, from the emergence of axons to the formation of functional synapses. By combining live imaging approaches with tools designed to measure and manipulate the mechanical environment of neurons, the emerging field of neuromechanics will add a new paradigm in our understanding of neuronal development and potentially inspire novel regenerative therapies.


Assuntos
Sinais (Psicologia) , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Neurônios/citologia , Sinapses/fisiologia , Animais , Neurônios/metabolismo
10.
Hum Mol Genet ; 24(17): 4997-5014, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26071364

RESUMO

Agenesis of the corpus callosum (AgCC) is a frequent brain disorder found in over 80 human congenital syndromes including ciliopathies. Here, we report a severe AgCC in Ftm/Rpgrip1l knockout mouse, which provides a valuable model for Meckel-Grüber syndrome. Rpgrip1l encodes a protein of the ciliary transition zone, which is essential for ciliogenesis in several cell types in mouse including neuroepithelial cells in the developing forebrain. We show that AgCC in Rpgrip1l(-/-) mouse is associated with a disturbed location of guidepost cells in the dorsomedial telencephalon. This mislocalization results from early patterning defects and abnormal cortico-septal boundary (CSB) formation in the medial telencephalon. We demonstrate that all these defects primarily result from altered GLI3 processing. Indeed, AgCC, together with patterning defects and mispositioning of guidepost cells, is rescued by overexpressing in Rpgrip1l(-/-) embryos, the short repressor form of the GLI3 transcription factor (GLI3R), provided by the Gli3(Δ699) allele. Furthermore, Gli3(Δ699) also rescues AgCC in Rfx3(-/-) embryos deficient for the ciliogenic RFX3 transcription factor that regulates the expression of several ciliary genes. These data demonstrate that GLI3 processing is a major outcome of primary cilia function in dorsal telencephalon morphogenesis. Rescuing CC formation in two independent ciliary mutants by GLI3(Δ699) highlights the crucial role of primary cilia in maintaining the proper level of GLI3R required for morphogenesis of the CC.


Assuntos
Cílios/metabolismo , Corpo Caloso/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Agenesia do Corpo Caloso/embriologia , Agenesia do Corpo Caloso/genética , Agenesia do Corpo Caloso/metabolismo , Animais , Padronização Corporal/genética , Transtornos da Motilidade Ciliar/genética , Transtornos da Motilidade Ciliar/metabolismo , Corpo Caloso/enzimologia , Corpo Caloso/patologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Encefalocele/genética , Encefalocele/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Knockout , Mutação , Neocórtex/embriologia , Neocórtex/metabolismo , Neocórtex/patologia , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Doenças Renais Policísticas/genética , Doenças Renais Policísticas/metabolismo , Fatores de Transcrição de Fator Regulador X , Retinose Pigmentar , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteína Gli3 com Dedos de Zinco
11.
Dev Biol ; 401(1): 25-36, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25541234

RESUMO

Key to morphogenesis is the orchestration of cell movements in the embryo, which requires fine-tuned adhesive interactions between cells and their close environment. The neural crest paradigm has provided important insights into how adhesion dynamics control epithelium-to-mesenchyme transition and mesenchymal cell migration. Much less is known about cranial placodes, patches of ectodermal cells that generate essential parts of vertebrate sensory organs and ganglia. In this review, we summarise the known functions of adhesion molecules in cranial placode morphogenesis, and discuss potential novel implications of adhesive interactions in this crucial developmental process. The great repertoire of placodal cell behaviours offers new avenues for exploring the multiple roles of adhesion complexes in epithelial remodelling, collective migration and neuronal movements.


Assuntos
Adesão Celular/fisiologia , Movimento Celular/fisiologia , Ectoderma/embriologia , Desenvolvimento Embrionário/fisiologia , Epitélio/embriologia , Modelos Biológicos , Morfogênese/fisiologia , Crânio/embriologia , Animais , Matriz Extracelular/fisiologia , Humanos , Crânio/citologia
12.
Nat Genet ; 39(7): 875-81, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17558409

RESUMO

Cerebello-oculo-renal syndrome (CORS), also called Joubert syndrome type B, and Meckel (MKS) syndrome belong to the group of developmental autosomal recessive disorders that are associated with primary cilium dysfunction. Using SNP mapping, we identified missense and truncating mutations in RPGRIP1L (KIAA1005) in both CORS and MKS, and we show that inactivation of the mouse ortholog Rpgrip1l (Ftm) recapitulates the cerebral, renal and hepatic defects of CORS and MKS. In addition, we show that RPGRIP1L colocalizes at the basal body and centrosomes with the protein products of both NPHP6 and NPHP4, known genes associated with MKS, CORS and nephronophthisis (a related renal disorder and ciliopathy). In addition, the RPGRIP1L missense mutations found in CORS individuals diminishes the interaction between RPGRIP1L and nephrocystin-4. Our findings show that mutations in RPGRIP1L can cause the multiorgan phenotypic abnormalities found in CORS or MKS, which therefore represent a continuum of the same underlying disorder.


Assuntos
Doenças Cerebelares/genética , Transtornos da Motilidade Ciliar/genética , Encefalocele/genética , Oftalmopatias/genética , Nefropatias/genética , Proteínas/genética , Animais , Criança , Proteínas do Citoesqueleto , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Camundongos Mutantes , Mutação Puntual , Síndrome
13.
J Neurosci ; 33(40): 15726-34, 2013 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-24089481

RESUMO

Although mRNA was once thought to be excluded from the axonal compartment, the existence of protein synthesis in growing or regenerating axons in culture is now generally accepted. However, its extent and functional importance remain a subject of intense investigation. Furthermore, unambiguous evidence of mRNA axonal transport and local translation in vivo, in the context of a whole developing organism is still lacking. Here, we provide direct evidence of the presence of mRNAs of the tubb5, nefma, and stmnb2 genes in several types of axons in the developing zebrafish (Danio rerio) embryo, with frequent accumulation at the growth cone. We further show that axonal localization of mRNA is a specific property of a subset of genes, as mRNAs of the huc and neurod genes, abundantly expressed in neurons, were not found in axons. We set up a reporter system in which the 3' untranslated region (UTR) of candidate mRNA, fused to a fluorescent protein coding sequence, was expressed in isolated neurons of the zebrafish embryo. Using this reporter, we identified in the 3'UTR of tubb5 mRNA a motif necessary and sufficient for axonal localization. Our work thus establishes the zebrafish as a model system to study axonal transport in a whole developing vertebrate organism, provides an experimental frame to assay this transport in vivo and to study its mechanisms, and identifies a new zipcode involved in axonal mRNA localization.


Assuntos
Axônios/metabolismo , Cones de Crescimento/metabolismo , Neurônios/metabolismo , Transporte de RNA/fisiologia , RNA Mensageiro/metabolismo , Peixe-Zebra/metabolismo , Animais , Transporte Axonal/fisiologia , Proteínas de Neurofilamentos/genética , Proteínas de Neurofilamentos/metabolismo , Estatmina/genética , Estatmina/metabolismo , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
14.
Development ; 138(10): 2079-88, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21490064

RESUMO

Primary cilia have essential functions in vertebrate development and signaling. However, little is known about cilia function in brain morphogenesis, a process that is severely affected in human ciliopathies. Here, we study telencephalic morphogenesis in a mouse mutant for the ciliopathy gene Ftm (Rpgrip1l). We show that the olfactory bulbs are present in an ectopic location in the telencephalon of Ftm(-/-) fetuses and do not display morphological outgrowth at the end of gestation. Investigating the developmental origin of this defect, we have established that E12.5 Ftm(-/-) telencephalic neuroepithelial cells lack primary cilia. Moreover, in the anterior telencephalon, the subpallium is expanded at the expense of the pallium, a phenotype reminiscent of Gli3 mutants. This phenotype indeed correlates with a decreased production of the short form of the Gli3 protein. Introduction of a Gli3 mutant allele encoding the short form of Gli3 into Ftm mutants rescues both telencephalic patterning and olfactory bulb morphogenesis, despite the persistence of cilia defects. Together, our results show that olfactory bulb morphogenesis depends on primary cilia and that the essential role of cilia in this process is to produce processed Gli3R required for developmental patterning. Our analysis thus provides the first in vivo demonstration that primary cilia control a developmental process via production of the short, repressor form of Gli3. Moreover, our findings shed light on the developmental origin of olfactory bulb agenesis and of other brain morphogenetic defects found in human diseases affecting the primary cilium.


Assuntos
Cílios/fisiologia , Fatores de Transcrição Kruppel-Like/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Telencéfalo/embriologia , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Sequência de Bases , Padronização Corporal , Diferenciação Celular , Primers do DNA/genética , Feminino , Humanos , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Mutantes , Microscopia Eletrônica de Varredura , Morfogênese , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação , Proteínas do Tecido Nervoso/genética , Bulbo Olfatório/citologia , Bulbo Olfatório/embriologia , Bulbo Olfatório/metabolismo , Gravidez , Processamento de Proteína Pós-Traducional , Células Receptoras Sensoriais/citologia , Telencéfalo/citologia , Telencéfalo/metabolismo , Proteína Gli3 com Dedos de Zinco
15.
Hum Mol Genet ; 20(13): 2611-27, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21498478

RESUMO

Nephronophthisis is a hereditary nephropathy characterized by interstitial fibrosis and cyst formation. It is caused by mutations in NPHP genes encoding the ciliary proteins, nephrocystins. In this paper, we investigate the function of nephrocystin-4, the product of the nphp4 gene, in vivo by morpholino-mediated knockdown in zebrafish and in vitro in mammalian kidney cells. Depletion of nephrocystin-4 results in convergence and extension defects, impaired laterality, retinal anomalies and pronephric cysts associated with alterations in early cloacal morphogenesis. These defects are accompanied by abnormal ciliogenesis in the cloaca and in the laterality organ. We show that nephrocystin-4 is required for the elongation of the caudal pronephric primordium and for the regulation of cell rearrangements during cloaca morphogenesis. Moreover, depletion of either inversin, the product of the nphp2 gene, or of the Wnt-planar cell polarity (PCP) pathway component prickle2 increases the proportion of cyst formation in nphp4-depleted embryos. Nephrocystin-4 represses the Wnt-ß-catenin pathway in the zebrafish cloaca and in mammalian kidney cells in culture. In these cells, nephrocystin-4 interacts with inversin and dishevelled, and regulates dishevelled stability and subcellular localization. Our data point to a function of nephrocystin-4 in a tight regulation of the Wnt-ß-catenin and Wnt-PCP pathways, in particular during morphogenesis of the zebrafish pronephros. Moreover, they highlight common signalling functions for inversin and nephrocystin-4, suggesting that these two nephrocystins are involved in common physiopathological mechanisms.


Assuntos
Morfogênese/genética , Transdução de Sinais/genética , Proteínas Wnt/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Animais Geneticamente Modificados , Apoptose/genética , Linhagem Celular , Cílios/genética , Cílios/patologia , Proteínas Desgrenhadas , Cães , Células HEK293 , Humanos , Mitose/genética , Fenótipo , Fosfoproteínas/metabolismo , Ligação Proteica/genética , Estabilidade Proteica , Transporte Proteico/genética , Proteínas de Peixe-Zebra/genética , beta Catenina/metabolismo
16.
Haematologica ; 97(3): 379-87, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22058212

RESUMO

BACKGROUND: The nucleoporin gene NUP98 is rearranged in more than 27 chromosomal abnormalities observed in childhood and adult, de novo and therapy-related acute leukemias of myeloid and T-lymphoid origins, resulting in the creation of fusion genes and the expression of chimeric proteins. We report here the functional analysis of the NUP98-coiled-coil domain-containing protein 28A (NUP98-CCDC28A) fusion protein, expressed as the consequence of a recurrent t(6;11)(q24.1;p15.5) translocation. DESIGN AND METHODS: To gain insight into the function of the native CCDC28A gene, we collected information on any differential expression of CCDC28A among normal hematologic cell types and within subgroups of acute leukemia. To assess the in vivo effects of the NUP98-CCDC28A fusion, NUP98-CCDC28A or full length CCDC28A were retrovirally transduced into primary murine bone marrow cells and transduced cells were next transplanted into sub-lethally irradiated recipient mice. RESULTS: Our in silico analyses supported a contribution of CCDC28A to discrete stages of murine hematopoietic development. They also suggested selective enrichment of CCDC28A in the French-American-British M6 class of human acute leukemia. Primary murine hematopoietic progenitor cells transduced with NUP98-CCDC28A generated a fully penetrant and transplantable myeloproliferative neoplasm-like myeloid leukemia and induced selective expansion of granulocyte/macrophage progenitors in the bone marrow of transplanted recipients, showing that NUP98-CCDC28A promotes the proliferative capacity and self-renewal potential of myeloid progenitors. In addition, the transformation mediated by NUP98-CCDC28A was not associated with deregulation of the Hoxa-Meis1 pathway, a feature shared by a diverse set of NUP98 fusions. CONCLUSIONS: Our results demonstrate that the recurrent NUP98-CCDC28A is an oncogene that induces a rapid and transplantable myeloid neoplasm in recipient mice. They also provide additional evidence for an alternative leukemogenic mechanism for NUP98 oncogenes.


Assuntos
Complexo de Proteínas Formadoras de Poros Nucleares/genética , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteínas/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Células da Medula Óssea/metabolismo , Transplante de Medula Óssea , Núcleo Celular/metabolismo , Proliferação de Células , Cromossomos Humanos Par 11 , Cromossomos Humanos Par 6 , Expressão Gênica , Células Progenitoras de Granulócitos e Macrófagos/patologia , Proteínas de Homeodomínio/metabolismo , Humanos , Imunofenotipagem , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Proteína Meis1 , Transtornos Mieloproliferativos/genética , Transtornos Mieloproliferativos/metabolismo , Transtornos Mieloproliferativos/mortalidade , Proteínas de Neoplasias/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Isoformas de Proteínas/genética , Transporte Proteico , Proteínas/metabolismo , Alinhamento de Sequência , Translocação Genética
17.
Nat Neurosci ; 11(3): 277-84, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18297065

RESUMO

Neural stem cells that continue to produce neurons are retained in the adult hippocampal dentate gyrus. The mechanisms by which embryonic neural progenitors expand and transform into postnatal neural stem cells, an essential process for the continual production of neurons throughout life, remain unknown. We found that radial astrocytes, the postnatal progenitors in the dentate gyrus, failed to develop after embryonic ablation of ciliary genes or Smoothened (Smo), an essential component for Sonic hedgehog (Shh) signaling. Postnatal dentate neurogenesis failed in these mutant mice, and the dentate gyrus became severely hypotrophic. In contrast, expression of a constitutively active Smo (SmoM2-YFP) resulted in a marked expansion of the dentate gyrus. Double-mutant analyses suggested that both wild-type Smo and SmoM2-YFP function through the primary cilia. We conclude that Shh signaling, acting through the primary cilia, has a critical role in the expansion and establishment of postnatal hippocampal progenitors.


Assuntos
Diferenciação Celular/genética , Cílios/metabolismo , Proteínas Hedgehog/metabolismo , Hipocampo/embriologia , Hipocampo/crescimento & desenvolvimento , Células-Tronco/metabolismo , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Astrócitos/citologia , Astrócitos/metabolismo , Proliferação de Células , Células Cultivadas , Cílios/ultraestrutura , Giro Denteado/citologia , Giro Denteado/embriologia , Giro Denteado/crescimento & desenvolvimento , Proteínas Hedgehog/genética , Hipocampo/citologia , Cinesinas/genética , Cinesinas/metabolismo , Camundongos , Camundongos Knockout , Camundongos Mutantes Neurológicos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/genética , Receptor Smoothened , Células-Tronco/ultraestrutura
18.
Mol Biol Cell ; 32(8): 675-689, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33625872

RESUMO

A range of severe human diseases called ciliopathies is caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme, and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localize to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Antígenos de Neoplasias/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cílios/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Animais , Antígenos de Neoplasias/fisiologia , Axonema/metabolismo , Corpos Basais/metabolismo , Proteínas de Ciclo Celular/fisiologia , Centríolos/metabolismo , Cílios/fisiologia , Ciliopatias/metabolismo , Ciliopatias/fisiopatologia , Proteínas do Citoesqueleto/fisiologia , Células HEK293 , Humanos , Camundongos , Mutação , Células NIH 3T3 , Transdução de Sinais
19.
Dev Biol ; 327(2): 566-77, 2009 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-19152797

RESUMO

Patterning of the vertebrate hindbrain involves a segmentation process leading to the formation of seven rhombomeres along the antero-posterior axis. While recent studies have shed light on the mechanisms underlying progressive subdivision of the posterior hindbrain into individual rhombomeres, the early events involved in anterior hindbrain patterning are still largely unknown. In this paper we demonstrate that two zebrafish Iroquois transcription factors, Irx7 and Irx1b, are required for the proper formation and specification of rhombomeres 1 to 4 and, in particular, for krox20 activation in r3. We also show that Irx7 functionally interacts with Meis factors to activate the expression of anterior hindbrain markers, such as hoxb1a, hoxa2 and krox20, ectopically in the anterior neural plate. Then, focusing on krox20 expression, we show that the effect of Irx7 and Meis1.1 is mediated by element C, a conserved cis-regulatory element involved in krox20 activation in the hindbrain. Together, our data point to an essential function of Iroquois transcription factors in krox20 activation and, more generally, in anterior hindbrain specification.


Assuntos
Padronização Corporal/fisiologia , Proteína 2 de Resposta de Crescimento Precoce/metabolismo , Proteínas de Homeodomínio/metabolismo , Rombencéfalo , Fatores de Transcrição/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra , Animais , Biomarcadores/metabolismo , Proteína 2 de Resposta de Crescimento Precoce/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Hibridização In Situ , Proteína Meis1 , Placa Neural/anatomia & histologia , Placa Neural/fisiologia , Elementos Reguladores de Transcrição , Rombencéfalo/anatomia & histologia , Rombencéfalo/embriologia , Fatores de Transcrição/genética , Peixe-Zebra/anatomia & histologia , Peixe-Zebra/embriologia , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética
20.
Sci Adv ; 6(36)2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32917588

RESUMO

The primary cilium (PC) is a small centrosome-assembled organelle, protruding from the surface of most eukaryotic cells. It plays a key role in cell migration, but the underlying mechanisms are unknown. Here, we show that the PC regulates neuronal migration via cyclic adenosine 3'-5' monosphosphate (cAMP) production activating centrosomal protein kinase A (PKA). Biosensor live imaging revealed a periodic cAMP hotspot at the centrosome of embryonic, postnatal, and adult migrating neurons. Genetic ablation of the PC, or knockdown of ciliary adenylate cyclase 3, caused hotspot disappearance and migratory defects, with defective centrosome dynamics and altered nucleokinesis. Delocalization of PKA from the centrosome phenocopied the migratory defects. Our results show that the PC and centrosome form a single cAMP signaling unit dynamically regulating migration, further highlighting the centrosome as a signaling hub.


Assuntos
Adenosina , Cílios , Adenosina/metabolismo , Movimento Celular , Centrossomo/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo
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