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1.
Development ; 148(16)2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34343262

RESUMO

Embryonic tissues are shaped by the dynamic behaviours of their constituent cells. To understand such cell behaviours and how they evolved, new approaches are needed to map out morphogenesis across different organisms. Here, we apply a quantitative approach to learn how the notochord forms during the development of amphioxus: a basally branching chordate. Using a single-cell morphometrics pipeline, we quantify the geometries of thousands of amphioxus notochord cells, and project them into a common mathematical space, termed morphospace. In morphospace, notochord cells disperse into branching trajectories of cell shape change, revealing a dynamic interplay between cell shape change and growth that collectively contributes to tissue elongation. By spatially mapping these trajectories, we identify conspicuous regional variation, both in developmental timing and trajectory topology. Finally, we show experimentally that, unlike ascidians but like vertebrates, posterior cell division is required in amphioxus to generate full notochord length, thereby suggesting this might be an ancestral chordate trait that is secondarily lost in ascidians. Altogether, our novel approach reveals that an unexpectedly complex scheme of notochord morphogenesis might have been present in the first chordates. This article has an associated 'The people behind the papers' interview.


Assuntos
Desenvolvimento Embrionário/fisiologia , Anfioxos/embriologia , Notocorda/embriologia , Organogênese/fisiologia , Análise de Célula Única/métodos , Animais , Divisão Celular/fisiologia , Forma Celular/fisiologia , Feminino , Masculino , Modelos Teóricos , Urocordados/embriologia
2.
J Morphol ; 282(10): 1437-1454, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34233026

RESUMO

The neural tube of amniotes is formed through different mechanisms that take place in the anterior and posterior regions and involve neural plate folding or mesenchymal condensation followed by its cavitation. Meanwhile, in teleost trunk region, the neural plate forms the neural keel, while the lumen develops later. However, the data on neurulation and other morphogenetic processes in the posterior body region in Teleostei remain fragmentary. We proposed that there could be variations in the morphogenetic processes, such as cell shape changes and cell rearrangements, in the posterior region compared to the anterior one at the different stages. Here, we performed morphological and histochemical analyses of morphogenetic processes with an emphasis on neurulation in the zebrafish tail bud (TB) and posterior region. To analyze the posterior expression of sox2 and tbxta we performed whole mount in situ hybridization. We showed that the TB cells of variable shapes and orientation are tightly packed, and the neural and notochord primordia develop first. The shape of the neural primordium undergoes numerous changes as a result of cell rearrangements leading to the development of the neural rod. At the prim-6 stage, the cells of the neural primordium directly form the neural rod. The neuroepithelial cells undergo sequential shape changes. At the stage of the neural rod formation, the apical regions of triangular neuroepithelial cells of the floor plate are enriched in F-actin. The neurocoel development onset is above the apical poles of neuroepithelial cells. The expression domains of sox2 and tbxta become more restricted during the development.


Assuntos
Neurulação , Peixe-Zebra , Animais , Mesoderma , Tubo Neural , Notocorda
3.
Nat Commun ; 12(1): 3277, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34078907

RESUMO

Generating properly differentiated embryonic structures in vitro from pluripotent stem cells remains a challenge. Here we show that instruction of aggregates of mouse embryonic stem cells with an experimentally engineered morphogen signalling centre, that functions as an organizer, results in the development of embryo-like entities (embryoids). In situ hybridization, immunolabelling, cell tracking and transcriptomic analyses show that these embryoids form the three germ layers through a gastrulation process and that they exhibit a wide range of developmental structures, highly similar to neurula-stage mouse embryos. Embryoids are organized around an axial chordamesoderm, with a dorsal neural plate that displays histological properties similar to the murine embryo neuroepithelium and that folds into a neural tube patterned antero-posteriorly from the posterior midbrain to the tip of the tail. Lateral to the chordamesoderm, embryoids display somitic and intermediate mesoderm, with beating cardiac tissue anteriorly and formation of a vasculature network. Ventrally, embryoids differentiate a primitive gut tube, which is patterned both antero-posteriorly and dorso-ventrally. Altogether, embryoids provide an in vitro model of mammalian embryo that displays extensive development of germ layer derivatives and that promises to be a powerful tool for in vitro studies and disease modelling.


Assuntos
Padronização Corporal/genética , Corpos Embrioides/metabolismo , Desenvolvimento Embrionário/genética , Células-Tronco Embrionárias Murinas/metabolismo , Transdução de Sinais/genética , Animais , Ectoderma/citologia , Ectoderma/crescimento & desenvolvimento , Ectoderma/metabolismo , Embrião de Mamíferos , Corpos Embrioides/citologia , Endoderma/citologia , Endoderma/crescimento & desenvolvimento , Endoderma/metabolismo , Fator de Transcrição GATA6/genética , Fator de Transcrição GATA6/metabolismo , Gástrula/citologia , Gástrula/crescimento & desenvolvimento , Gástrula/metabolismo , Gastrulação/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas HMGB/genética , Proteínas HMGB/metabolismo , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Proteína Homeobox Nanog/genética , Proteína Homeobox Nanog/metabolismo , Tubo Neural/citologia , Tubo Neural/crescimento & desenvolvimento , Tubo Neural/metabolismo , Notocorda/citologia , Notocorda/crescimento & desenvolvimento , Notocorda/metabolismo , Fatores de Transcrição SOXF/genética , Fatores de Transcrição SOXF/metabolismo
4.
Development ; 148(18)2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34086031

RESUMO

How force generated by the morphogenesis of one tissue impacts the morphogenesis of other tissues to achieve an elongated embryo axis is not well understood. The notochord runs along the length of the somitic compartment and is flanked on either side by somites. Vacuolating notochord cells undergo a constrained expansion, increasing notochord internal pressure and driving its elongation and stiffening. Therefore, the notochord is appropriately positioned to play a role in mechanically elongating the somitic compartment. We used multi-photon cell ablation to remove specific regions of the zebrafish notochord and quantify the impact on axis elongation. We show that anterior expansion generates a force that displaces notochord cells posteriorly relative to adjacent axial tissues, contributing to the elongation of segmented tissue during post-tailbud stages. Unexpanded cells derived from progenitors at the posterior end of the notochord provide resistance to anterior notochord cell expansion, allowing for stress generation along the anterior-posterior axis. Therefore, notochord cell expansion beginning in the anterior, and addition of cells to the posterior notochord, act as temporally coordinated morphogenetic events that shape the zebrafish embryo anterior-posterior axis.


Assuntos
Embrião não Mamífero/fisiologia , Desenvolvimento Embrionário/fisiologia , Notocorda/fisiologia , Peixe-Zebra/fisiologia , Animais , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Morfogênese/fisiologia , Notocorda/metabolismo , Somitos/metabolismo , Somitos/fisiologia , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/metabolismo
5.
Genes (Basel) ; 12(3)2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809016

RESUMO

MicroRNAs are frequently clustered in the genome and polycistronically transcribed, regulating targeted genes in diverse signaling pathways. The miR-17-92 cluster is a typical miRNA cluster, playing crucial roles in the organogenesis and homeostasis of physiological processes in vertebrates. Here, we identified three miRNAs (csa-miR-92a, csa-miR-92b, and csa-miR-92c) that belonged to the miR-92 family and formed a miRNA cluster in the genome of a urochordate marine ascidian Ciona savignyi. Except for miR-92a and miR-92b, other homologs of the vertebrate miR-17-92 cluster members could not be identified in the Ciona genome. We further found that the mature sequences of urochordate miR-92 family members were highly conserved compared with the vertebrate species. The expression pattern revealed that three miR-92 family members had consistent expression levels in adult tissues and were predominantly expressed in heart and muscle tissue. We further showed that, at the embryonic and larval stages, csa-miR-92c was expressed in the notochord of embryos during 18-31 h post fertilization (hpf) by in situ hybridization. Knockout of csa-miR-92c resulted in the disorganization of notochord cells and the block of lumen coalescence in the notochord. Fibroblast growth factor (FGF), mitogen-activated protein kinase (MAPK), and wingless/integrated (Wnt)/planar cell polarity (PCP) signaling pathways might be involved in the regulatory processes, since a large number of core genes of these pathways were the predicted target genes of the miR-92 family. Taken together, we identified a miR-92 cluster in urochordate Ciona and revealed the expression patterns and the regulatory roles of its members in organogenesis. Our results provide expression and phylogenetic data on the understanding of the miR-92 miRNA cluster's function during evolution.


Assuntos
Ciona/crescimento & desenvolvimento , Ciona/genética , MicroRNAs/genética , Notocorda/crescimento & desenvolvimento , Urocordados/crescimento & desenvolvimento , Urocordados/genética , Animais , Polaridade Celular/genética , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento/genética , Genoma/genética , Larva/genética , Larva/crescimento & desenvolvimento , Filogenia , Transdução de Sinais/genética , Vertebrados/genética , Vertebrados/crescimento & desenvolvimento
6.
Indian J Pathol Microbiol ; 64(2): 410-412, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33851648

RESUMO

We present a case of a 48-year-old man's unexpected death affected by a relapsed clivalchordoma. After partial excision surgery of the neoplasm, he manifested 5 days later, in conditions of well-being, a sudden lethal extracranial hemorrhage from nose and mouth. The autopsy examination and the subsequent histological investigations did not allow us to clarify the exact origin of the bleeding. Based on the negativity of the accurate examinations performed, the extent of the bleeding, and the findings highlighted by the means of the nuclear magnetic resonance (NMR) carried out a few days before death, we have considered reasonable to localize the source of hemorrhage in the intrapetrous tract of the left internal carotid artery. Since this is a unique event, never previously documented, we believe that our report may be of interest to the scientific community.


Assuntos
Cordoma/cirurgia , Morte Súbita , Hemorragia/mortalidade , Choque Hemorrágico/mortalidade , Autopsia , Artéria Carótida Interna/patologia , Cordoma/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Notocorda/patologia , Base do Crânio/patologia , Base do Crânio/cirurgia
7.
Integr Comp Biol ; 61(2): 358-369, 2021 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-33881514

RESUMO

Ascidians are invertebrate chordates, with swimming chordate tadpole larvae that have distinct heads and tails. The head contains the small brain, sensory organs, including the ocellus (light) and otolith (gravity) and the presumptive endoderm, while the tail has a notochord surrounded by muscle cells and a dorsal nerve cord. One of the chordate features is a post-anal tail. Ascidian tadpoles are nonfeeding, and their tails are critical for larval locomotion. After hatching the larvae swim up toward light and are carried by the tide and ocean currents. When competent to settle, ascidian tadpole larvae swim down, away from light, to settle and metamorphose into a sessile adult. Tunicates are classified as chordates because of their chordate tadpole larvae; in contrast, the sessile adult has a U-shaped gut and very derived body plan, looking nothing like a chordate. There is one group of ascidians, the Molgulidae, where many species are known to have tailless larvae. The Swalla Lab has been studying the evolution of tailless ascidian larvae in this clade for over 30 years and has shown that tailless larvae have evolved independently several times in this clade. Comparison of the genomes of two closely related species, the tailed Molgula oculata and tailless Molgula occulta reveals much synteny, but there have been multiple insertions and deletions that have disrupted larval genes in the tailless species. Genomics and transcriptomics have previously shown that there are pseudogenes expressed in the tailless embryos, suggesting that the partial rescue of tailed features in their hybrid larvae is due to the expression of intact genes from the tailed parent. Yet surprisingly, we find that the notochord gene regulatory network is mostly intact in the tailless M. occulta, although the notochord does not converge and extend and remains as an aggregate of cells we call the "notoball." We expect that eventually many of the larval gene networks will become evolutionarily lost in tailless ascidians and the larval body plan abandoned, with eggs developing directly into an adult. Here we review the current evolutionary and developmental evidence on how the molgulids lost their tails.


Assuntos
Evolução Biológica , Larva/anatomia & histologia , Cauda , Urocordados , Animais , Notocorda , Urocordados/anatomia & histologia
8.
Artigo em Inglês | MEDLINE | ID: mdl-33529709

RESUMO

A dithiocarbamate (DTC) fungicide, propineb, affects thyroid function and exerts immunotoxicity, cytotoxicity, and neurotoxicity in humans. Long-term exposure to propineb is associated with carcinogenicity, teratogenicity, malfunction of the reproductive system, and abnormalities in vital signs during organ development. However, there is no evidence of acute toxicity attributable to propineb in zebrafish. Therefore, in the present study, we assessed the toxicity of propineb in zebrafish by studying its adverse effects on embryo development, angiogenesis, and notochord development. Embryos with propineb exposure developed morphological and physiological defects and in larvae, apoptosis and notochord defects were induced in the early development stage. Transgenic fli1:eGFP zebrafish exposed to propineb showed abnormal larval development with defects in angiogenesis and deformed vasculature. Propineb induced irreversible damage to the neural development of embryos and neurogenic defects in developing zebrafish in transgenic olig2:dsRED zebrafish. These results show that exposure to propineb triggers abnormalities in different organ systems of zebrafish and suggests the physiological complexity of the response to propineb.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Fungicidas Industriais/toxicidade , Peixe-Zebra/embriologia , Zineb/análogos & derivados , Animais , Neovascularização Fisiológica/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Notocorda/efeitos dos fármacos , Zineb/toxicidade
9.
PLoS Genet ; 17(1): e1009305, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33465083

RESUMO

Many genes are regulated by two or more enhancers that drive similar expression patterns. Evolutionary theory suggests that these seemingly redundant enhancers must have functionally important differences. In the simple ascidian chordate Ciona, the transcription factor Brachyury is induced exclusively in the presumptive notochord downstream of lineage specific regulators and FGF-responsive Ets family transcription factors. Here we exploit the ability to finely titrate FGF signaling activity via the MAPK pathway using the MEK inhibitor U0126 to quantify the dependence of transcription driven by different Brachyury reporter constructs on this direct upstream regulator. We find that the more powerful promoter-adjacent proximal enhancer and a weaker distal enhancer have fundamentally different dose-response relationships to MAPK inhibition. The Distal enhancer is more sensitive to MAPK inhibition but shows a less cooperative response, whereas the Proximal enhancer is less sensitive and more cooperative. A longer construct containing both enhancers has a complex dose-response curve that supports the idea that the proximal and distal enhancers are moderately super-additive. We show that the overall expression loss from intermediate doses of U0126 is not only a function of the fraction of cells expressing these reporters, but also involves graded decreases in expression at the single-cell level. Expression of the endogenous gene shows a comparable dose-response relationship to the full length reporter, and we find that different notochord founder cells are differentially sensitive to MAPK inhibition. Together, these results indicate that although the two Brachyury enhancers have qualitatively similar expression patterns, they respond to FGF in quantitatively different ways and act together to drive high levels of Brachyury expression with a characteristic input/output relationship. This indicates that they are fundamentally not equivalent genetic elements.


Assuntos
Ciona intestinalis/genética , Elementos Facilitadores Genéticos/genética , Proteínas Fetais/genética , Fatores de Crescimento de Fibroblastos/genética , Proteínas com Domínio T/genética , Sequência de Aminoácidos/genética , Animais , Ciona intestinalis/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/genética , Sistema de Sinalização das MAP Quinases/genética , Notocorda/crescimento & desenvolvimento , Notocorda/metabolismo , Regiões Promotoras Genéticas/genética , Fatores de Transcrição/genética
10.
Development ; 148(3)2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33419874

RESUMO

The notochord is a defining feature of the chordates. The transcription factor Brachyury (Bra) is a key regulator of notochord fate but here we show that it is not a unitary master regulator in the model chordate Ciona Ectopic Bra expression only partially reprograms other cell types to a notochord-like transcriptional profile and a subset of notochord-enriched genes is unaffected by CRISPR Bra disruption. We identify Foxa.a and Mnx as potential co-regulators, and find that combinatorial cocktails are more effective at reprogramming other cell types than Bra alone. We reassess the network relationships between Bra, Foxa.a and other components of the notochord gene regulatory network, and find that Foxa.a expression in the notochord is regulated by vegetal FGF signaling. It is a direct activator of Bra expression and has a binding motif that is significantly enriched in the regulatory regions of notochord-enriched genes. These and other results indicate that Bra and Foxa.a act together in a regulatory network dominated by positive feed-forward interactions, with neither being a classically defined master regulator.


Assuntos
Ciona/genética , Ciona/metabolismo , Proteínas Fetais/genética , Proteínas Fetais/metabolismo , Notocorda/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Animais , Ciona intestinalis/genética , Ciona intestinalis/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Redes Reguladoras de Genes , Notocorda/crescimento & desenvolvimento , Transativadores , Fatores de Transcrição/metabolismo
11.
Anat Rec (Hoboken) ; 304(8): 1629-1649, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33155751

RESUMO

While it is well known that the notochord of bony fishes changes over developmental time, less is known about how it varies across different body regions. In the development of the Atlantic salmon, Salmo salar L., cranial and caudal ends of the notochord are overlaid by the formation of the bony elements of the neurocranium and caudal fin, respectively. To investigate, we describe how the notochord of the cranium and caudal fin changes from embryo to spawning adult, using light microscopy, SEM, TEM, dissection, and CT scanning. The differences are dramatic. In contrast to the abdominal and caudal regions, at the ends of the notochord vertebrae never develop. While the cranial notochord builds a tapering, unsegmented cone of chordal bone, the urostylic notochordal sheath never ossifies: adjacent, irregular bony elements form from the endoskeleton of the caudal fin. As development progresses, two previously undescribed processes occur. First, the bony cone of the cranial notochord, and its internal chordocytes, are degraded by chordoclasts, an undescribed function of the clastic cell type. Second, the sheath of the urostylic notochord creates transverse septae that partly traverse the lumen in an irregular pattern. By the adult stage, the cranial notochord is gone. In contrast, the urostylic notochord in adults is robust, reinforced with septae, covered by irregularly shaped pieces of cellular bone, and capped with an opistural cartilage that develops from the sheath of the urostylic notochord. A previously undescribed muscle, with its origin on the opistural cartilage, inserts on the lepidotrich ventral to it.


Assuntos
Nadadeiras de Animais/embriologia , Notocorda/embriologia , Salmo salar/embriologia , Crânio/embriologia , Nadadeiras de Animais/crescimento & desenvolvimento , Animais , Notocorda/crescimento & desenvolvimento , Salmo salar/crescimento & desenvolvimento , Crânio/crescimento & desenvolvimento
12.
Mol Med Rep ; 23(2)2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33355376

RESUMO

The degeneration of intervertebral disc (IVD) tissue, initiated following the disappearance of notochordal cells (NCs), is characterized by the decreased number of nucleus pulposus (NP) cells (NPCs) and extracellular matrix. Transplanting proper cells into the IVD may sustain cell numbers, resulting in the synthesis of new matrix; this represents a minimally invasive regenerative therapy. However, the lack of cells with a correct phenotype severely hampers the development of regenerative therapy. The present study aimed to investigate whether porcine NC­rich NP tissue stimulates bone marrow­derived mesenchymal stem cell (BM­MSC) differentiation toward NC­like cells, which possess promising regenerative ability, for the treatment of disc degeneration diseases. BM­MSCs were successfully isolated from porcine femurs and tibiae, which expressed CD90 and CD105 markers and did not express CD45. Differentiation induction experiments revealed that the isolated cells had osteogenic and adipogenic differentiation potential. When co­cultured with NC­rich NP tissue, the BM­MSCs successfully differentiated into NC­like cells. Cell morphological analysis revealed that the cells exhibited an altered morphology, from a shuttle­like to a circular one, and the expression of NC marker genes, including brachyury, keratin­8, and keratin­18, was enhanced, and the cells exhibited the ability to generate aggrecan and collagen II. Taken together, the findings of the present study demonstrated that the primarily isolated and cultured BM­MSCs may be stimulated to differentiate into NC­like cells by porcine NC­rich NP explants, potentially providing an ideal cell source for regenerative therapies for disc degeneration diseases.


Assuntos
Células da Medula Óssea/metabolismo , Diferenciação Celular , Células-Tronco Mesenquimais/metabolismo , Notocorda/metabolismo , Núcleo Pulposo/metabolismo , Animais , Células da Medula Óssea/citologia , Masculino , Células-Tronco Mesenquimais/citologia , Notocorda/citologia , Núcleo Pulposo/citologia , Suínos
13.
Development ; 147(24)2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33361090

RESUMO

Ventral bending of the embryonic tail within the chorion is an evolutionarily conserved morphogenetic event in both invertebrates and vertebrates. However, the complexity of the anatomical structure of vertebrate embryos makes it difficult to experimentally identify the mechanisms underlying embryonic folding. This study investigated the mechanisms underlying embryonic tail bending in chordates. To further understand the mechanical role of each tissue, we also developed a physical model with experimentally measured parameters to simulate embryonic tail bending. Actomyosin asymmetrically accumulated at the ventral side of the notochord, and cell proliferation of the dorsal tail epidermis was faster than that in the ventral counterpart during embryonic tail bending. Genetic disruption of actomyosin activity and inhibition of cell proliferation dorsally caused abnormal tail bending, indicating that both asymmetrical actomyosin contractility in the notochord and the discrepancy of epidermis cell proliferation are required for tail bending. In addition, asymmetrical notochord contractility was sufficient to drive embryonic tail bending, whereas differential epidermis proliferation was a passive response to mechanical forces. These findings showed that asymmetrical notochord contractility coordinates with differential epidermis proliferation mechanisms to drive embryonic tail bending.This article has an associated 'The people behind the papers' interview.


Assuntos
Actomiosina/genética , Morfogênese/genética , Cauda/crescimento & desenvolvimento , Actomiosina/metabolismo , Animais , Proliferação de Células/genética , Ciona/embriologia , Ciona/genética , Ciona/crescimento & desenvolvimento , Células Epiteliais/metabolismo , Contração Muscular/fisiologia , Notocorda/embriologia , Notocorda/crescimento & desenvolvimento , Cauda/embriologia
14.
Development ; 147(22)2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33051257

RESUMO

The notochord drives longitudinal growth of the body axis by convergent extension, a highly conserved developmental process that depends on non-canonical Wnt/planar cell polarity (PCP) signaling. However, the role of cell-matrix interactions mediated by integrins in the development of the notochord is unclear. We developed transgenic Cre mice, in which the ß1 integrin gene (Itgb1) is ablated at E8.0 in the notochord only or in the notochord and tail bud. These Itgb1 conditional mutants display misaligned, malformed vertebral bodies, hemi-vertebrae and truncated tails. From early somite stages, the notochord was interrupted and displaced in these mutants. Convergent extension of the notochord was impaired with defective cell movement. Treatment of E7.25 wild-type embryos with anti-ß1 integrin blocking antibodies, to target node pit cells, disrupted asymmetric localization of VANGL2. Our study implicates pivotal roles of ß1 integrin for the establishment of PCP and convergent extension of the developing notochord, its structural integrity and positioning, thereby ensuring development of the nucleus pulposus and the proper alignment of vertebral bodies and intervertebral discs. Failure of this control may contribute to human congenital spine malformations.


Assuntos
Movimento Celular , Integrina beta1/metabolismo , Disco Intervertebral/embriologia , Notocorda/embriologia , Coluna Vertebral/embriologia , Via de Sinalização Wnt , Animais , Integrina beta1/genética , Disco Intervertebral/citologia , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Notocorda/citologia , Coluna Vertebral/citologia
15.
Development ; 147(21)2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33023886

RESUMO

The vertebrate body plan is characterized by the presence of a segmented spine along its main axis. Here, we examine the current understanding of how the axial tissues that are formed during embryonic development give rise to the adult spine and summarize recent advances in the field, largely focused on recent studies in zebrafish, with comparisons to amniotes where appropriate. We discuss recent work illuminating the genetics and biological mechanisms mediating extension and straightening of the body axis during development, and highlight open questions. We specifically focus on the processes of notochord development and cerebrospinal fluid physiology, and how defects in those processes may lead to scoliosis.


Assuntos
Padronização Corporal , Vertebrados/embriologia , Animais , Morfogênese , Notocorda/embriologia , Escoliose/embriologia , Escoliose/patologia , Coluna Vertebral/anormalidades , Coluna Vertebral/embriologia , Coluna Vertebral/patologia
17.
Environ Toxicol Pharmacol ; 80: 103504, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980526

RESUMO

Toxicological effects of butylparaben (BuP) and ethylparaben (EtP) on zebrafish (Danio rerio) early-life stages are not well established. The present study evaluated, using zebrafish embryos and larvae, the toxicity of BuP and EtP through benchmark dose (BMD) approach. BuP was more toxic than EtP to zebrafish larvae. In fact, Lethal Concentration 50 (LC50) values at 96 h post-fertilization (hpf) for BuP and EtP were 2.34 mg/L and 20.86 mg/L, respectively. Indeed, BMD confidence interval (lower bound (BMDL) - upper bound (BMDU) was 0.91-1.92 mg/L for BuP and 10.8-17.4 mg/L for EtP. Zebrafish embryos exposed to 1 mg/L, 2.5 mg/L of BuP and 5 mg/L, 10 mg/L, 20 mg/L, 30 mg/L of EtP showed several developmental abnormalities and teratological effects compared to negative control. Exposed zebrafish developed reduced heartbeat, reduction in blood circulation, blood stasis, pericardial edema, deformed notochord and misshaped yolk sac. Embryos exposed to the highest concentrations of the chemicals (2.5 mg/L of BuP, 10 mg/L, 20 mg/L and 30 mg/L of EtP) showed the developmental abnormalities at 48 hpf while those treated with 1 mg/L of BuP and 10 mg/L of EtP reported behavioral changes at 72 hpf, including trembling of head, pectoral fins and spinal cord. This research identified the lethal and sublethal effects of BuP and EtP in zebrafish early-life stages and could be helpful to elucidate the developmental pathways of toxicity of parabens.


Assuntos
Parabenos/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/anormalidades , Animais , Comportamento Animal/efeitos dos fármacos , Circulação Sanguínea/efeitos dos fármacos , Edema/induzido quimicamente , Embrião não Mamífero/anormalidades , Embrião não Mamífero/efeitos dos fármacos , Feminino , Hemostasia/efeitos dos fármacos , Larva/efeitos dos fármacos , Dose Letal Mediana , Masculino , Notocorda/anormalidades , Notocorda/efeitos dos fármacos , Pericárdio/efeitos dos fármacos , Pericárdio/patologia , Saco Vitelino/anormalidades , Saco Vitelino/efeitos dos fármacos
18.
Mol Genet Genomic Med ; 8(10): e1375, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32738032

RESUMO

BACKGROUND: The Oculo-Auriculo-Vertebral Spectrum (OAVS) or Goldenhar Syndrome is an embryonic developmental disorder characterized by hemifacial microsomia associated with auricular, ocular and vertebral malformations. The clinical heterogeneity of this spectrum and its incomplete penetrance limited the molecular diagnosis. In this study, we describe a novel causative gene, ZYG11B. METHODS: A sporadic case of OAVS was analyzed by whole exome sequencing in trio strategy. The identified candidate gene, ZYG11B, was screened in 143 patients by next generation sequencing. Overexpression and immunofluorescence of wild-type and mutated ZYG11B forms were performed in Hela cells. Moreover, morpholinos were used for transient knockdown of its homologue in zebrafish embryo. RESULTS: A nonsense de novo heterozygous variant in ZYG11B, (NM_024646, c.1609G>T, p.Glu537*) was identified in a single OAVS patient. This variant leads in vitro to a truncated protein whose subcellular localization is altered. Transient knockdown of the zebrafish homologue gene confirmed its role in craniofacial cartilages architecture and in notochord development. Moreover, ZYG11B expression regulates a cartilage master regulator, SOX6, and is regulated by Retinoic Acid, a known developmental toxic molecule leading to clinical features of OAVS. CONCLUSION: Based on genetic, cellular and animal model data, we proposed ZYG11B as a novel rare causative gene for OAVS.


Assuntos
Proteínas de Ciclo Celular/genética , Síndrome de Goldenhar/genética , Adolescente , Animais , Proteínas de Ciclo Celular/metabolismo , Códon sem Sentido , Exoma , Síndrome de Goldenhar/metabolismo , Síndrome de Goldenhar/patologia , Células HeLa , Heterozigoto , Humanos , Masculino , Notocorda/embriologia , Notocorda/metabolismo , Fatores de Transcrição SOXD/genética , Fatores de Transcrição SOXD/metabolismo , Tretinoína/metabolismo , Peixe-Zebra
19.
Int J Dev Biol ; 64(1-2-3): 45-57, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32659017

RESUMO

The chick embryo ectoblast was examined for a possible relationship between the state of neural competence and cell population growth. It was found that although ectoblast cells with doubling times ranging between 5 to 20 h exhibit neural competence, the extent of neutralization induced by the Hensen's node depends on the duration of the cell cycle; the longer the doubling time of the competent ectoblast, the stronger the induction and the greater the induced neural tissue. Neural induction in the competent ectoblast occurs in at least two steps: the first lasts for 1-2 h of direct contact with the inducing Hensen's node graft; a contact for another 2 h with even a non-inducing post-nodal fragment is essential to consolidate neutralization. Hensen's node graft induces mitotic activity in the competent ectoblast in contact. Teratogens which inhibit cell population growth, development and blastoderm expansion in chick embryo gastrula cause concomitant caudalization of the embryonic axis. We confirm Yamada's hypothesis that dorsalization is under positive mitogenic control, whereas caudalization is controlled by a negative cell cycle regulation. Reverse transcripts of chick gastrula mRNA were cloned in pBR322. Colony hybridization with cDNA made against chicken yolk RNA showed positive clones. Thus chicken yolk contains maternal mRNAs. cDNA made against mRNA extracted from stage 10 foreheads was hybridized with RNA from stage 1 to 13 embryos, 19 day lens and egg yolk. The hybridization signal, which was low between stages 1 to 7, increased between stages 10-13 and decreased thereafter. Forehead cDNA also hybridized to yolk RNA. Thus, maternal RNA sequences are present in the early chick embryo. During lens development, epithelial cells retain proliferative activity and their progeny reaching a stationary phase join the fibre area and contribute to the growth of fibre cells. The rate of transfer from epithelium to fibre regulates the rate of programmed cell death of the non-dividing differentiated lens fibre cells.


Assuntos
Apoptose , Blastoderma/embriologia , Diferenciação Celular , Processos de Crescimento Celular , Cristalino/patologia , Morfogênese , Notocorda/embriologia , Animais , Embrião de Galinha , Galinhas
20.
Dev Biol ; 465(1): 1-10, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32628936

RESUMO

Protein phosphatases regulate a wide array of proteins through post-translational modification and are required for a plethora of intracellular events in eukaryotes. While some core components of the protein phosphatase complexes are well characterized, many subunits of these large complexes remain unstudied. Here we characterize a loss-of-function allele of the protein phosphatase 1 regulatory subunit 35 (Ppp1r35) gene. Homozygous mouse embryos lacking Ppp1r35 are developmental delayed beginning at embryonic day (E) 7.5 and have obvious morphological defects at later stages. Mutants fail to initiate turning and do not progress beyond the size or staging of normal E8.5 embryos. Consistent with recent in vitro studies linking PPP1R35 with the microcephaly protein Rotatin and with a role in centrosome formation, we show that Ppp1r35 mutant embryos lack primary cilia. Histological and molecular analysis of Ppp1r35 mutants revealed that notochord development is irregular and discontinuous and consistent with a role in primary cilia, that the floor plate of the neural tube is not specified. Similar to other mutant embryos with defects in centriole function, Ppp1r35 mutants displayed increased cell death that is prevalent in the neural tube and an increased number of proliferative cells in prometaphase. We hypothesize that loss of Ppp1r35 function abrogates centriole homeostasis, resulting in a failure to produce functional primary cilia, cell death and cell cycle delay/stalling that leads to developmental failure. Taken together, these results highlight the essential function of Ppp1r35 during early mammalian development and implicate this gene as a candidate for human microcephaly.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Ciclo Celular , Cílios/metabolismo , Notocorda/enzimologia , Organogênese , Animais , Proteínas de Ciclo Celular/genética , Cílios/genética , Camundongos , Camundongos Knockout
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