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1.
Science ; 370(6512): 113-116, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33004519

RESUMO

Animal development entails the organization of specific cell types in space and time, and spatial patterns must form in a robust manner. In the zebrafish spinal cord, neural progenitors form stereotypic patterns despite noisy morphogen signaling and large-scale cellular rearrangements during morphogenesis and growth. By directly measuring adhesion forces and preferences for three types of endogenous neural progenitors, we provide evidence for the differential adhesion model in which differences in intercellular adhesion mediate cell sorting. Cell type-specific combinatorial expression of different classes of cadherins (N-cadherin, cadherin 11, and protocadherin 19) results in homotypic preference ex vivo and patterning robustness in vivo. Furthermore, the differential adhesion code is regulated by the sonic hedgehog morphogen gradient. We propose that robust patterning during tissue morphogenesis results from interplay between adhesion-based self-organization and morphogen-directed patterning.


Assuntos
Padronização Corporal/fisiologia , Caderinas/metabolismo , Adesão Celular/fisiologia , Células-Tronco Neurais/fisiologia , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/crescimento & desenvolvimento , Animais , Padronização Corporal/genética , Caderinas/genética , Adesão Celular/genética , Medula Espinal/crescimento & desenvolvimento , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
2.
Nat Commun ; 11(1): 4399, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32879319

RESUMO

In cnidarians, axial patterning is not restricted to embryogenesis but continues throughout a prolonged life history filled with unpredictable environmental changes. How this developmental capacity copes with fluctuations of food availability and whether it recapitulates embryonic mechanisms remain poorly understood. Here we utilize the tentacles of the sea anemone Nematostella vectensis as an experimental paradigm for developmental patterning across distinct life history stages. By analyzing over 1000 growing polyps, we find that tentacle progression is stereotyped and occurs in a feeding-dependent manner. Using a combination of genetic, cellular and molecular approaches, we demonstrate that the crosstalk between Target of Rapamycin (TOR) and Fibroblast growth factor receptor b (Fgfrb) signaling in ring muscles defines tentacle primordia in fed polyps. Interestingly, Fgfrb-dependent polarized growth is observed in polyp but not embryonic tentacle primordia. These findings show an unexpected plasticity of tentacle development, and link post-embryonic body patterning with food availability.


Assuntos
Padronização Corporal , Anêmonas-do-Mar , Animais , Padronização Corporal/genética , Padronização Corporal/fisiologia , Desenvolvimento Embrionário/efeitos dos fármacos , Comportamento Alimentar , Regulação da Expressão Gênica no Desenvolvimento , Receptores de Fatores de Crescimento de Fibroblastos/genética , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo , Anêmonas-do-Mar/embriologia , Anêmonas-do-Mar/genética , Anêmonas-do-Mar/crescimento & desenvolvimento , Transdução de Sinais , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/metabolismo
3.
Proc Natl Acad Sci U S A ; 117(35): 21459-21468, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817436

RESUMO

Animal development has traditionally been viewed as an autonomous process directed by the host genome. But, in many animals, biotic and abiotic cues, like temperature and bacterial colonizers, provide signals for multiple developmental steps. Hydra offers unique features to encode these complex interactions of developmental processes with biotic and abiotic factors, and we used it here to investigate the impact of bacterial colonizers and temperature on the pattern formation process. In Hydra, formation of the head organizer involves the canonical Wnt pathway. Treatment with alsterpaullone (ALP) results in acquiring characteristics of the head organizer in the body column. Intriguingly, germfree Hydra polyps are significantly more sensitive to ALP compared to control polyps. In addition to microbes, ß-catenin-dependent pattern formation is also affected by temperature. Gene expression analyses led to the identification of two small secreted peptides, named Eco1 and Eco2, being up-regulated in the response to both Curvibacter sp., the main bacterial colonizer of Hydra, and low temperatures. Loss-of-function experiments revealed that Eco peptides are involved in the regulation of pattern formation and have an antagonistic function to Wnt signaling in Hydra.


Assuntos
Hydra/genética , Hydra/metabolismo , beta Catenina/metabolismo , Animais , Bactérias/metabolismo , Padronização Corporal/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Interação Gene-Ambiente , Hydra/fisiologia , Peptídeos/metabolismo , Temperatura , Proteínas Wnt/metabolismo , Via de Sinalização Wnt/genética , Via de Sinalização Wnt/fisiologia
4.
Dev Genes Evol ; 230(4): 305-314, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32671457

RESUMO

Crinoids are considered as the most basal extant echinoderms. They retain aboral nervous system with a nerve center, which has been degraded in the eleutherozoan echinoderms. To investigate the evolution of patterning of the nervous systems in crinoids, we examined temporal and spatial expression patterns of three neural patterning-related homeobox genes, six3, pax6, and otx, throughout the development of a feather star Anneissia japonica. These genes were involved in the patterning of endomesodermal tissues instead of the ectodermal neural tissues in the early planktonic stages. In the stages after larval attachment, the expression of these genes was mainly observed in the podia and the oral nervous systems instead of the aboral nerve center. Our results indicate the involvement of these three genes in the formation of oral nervous system in the common ancestor of the echinoderms and suggest that the aboral nerve center is not evolutionally related to the brain of other bilaterians.


Assuntos
Equinodermos/crescimento & desenvolvimento , Proteínas do Olho/metabolismo , Proteínas de Homeodomínio/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fatores de Transcrição Otx/metabolismo , Fator de Transcrição PAX6/metabolismo , Animais , Padronização Corporal/genética , Equinodermos/genética , Equinodermos/metabolismo , Evolução Molecular , Proteínas do Olho/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Proteínas de Homeodomínio/genética , Larva/genética , Larva/metabolismo , Proteínas do Tecido Nervoso/genética , Sistema Nervoso/crescimento & desenvolvimento , Sistema Nervoso/metabolismo , Neurônios , Fatores de Transcrição Otx/genética , Fator de Transcrição PAX6/genética
5.
PLoS Biol ; 18(7): e3000561, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32702011

RESUMO

Maternal ß-catenin activity is essential and critical for dorsal induction and its dorsal activation has been thoroughly studied. However, how the maternal ß-catenin activity is suppressed in the nondorsal cells remains poorly understood. Nanog is known to play a central role for maintenance of the pluripotency and maternal -zygotic transition (MZT). Here, we reveal a novel role of Nanog as a strong repressor of maternal ß-catenin signaling to safeguard the embryo against hyperactivation of maternal ß-catenin activity and hyperdorsalization. In zebrafish, knockdown of nanog at different levels led to either posteriorization or dorsalization, mimicking zygotic or maternal activation of Wnt/ß-catenin activities, and the maternal zygotic mutant of nanog (MZnanog) showed strong activation of maternal ß-catenin activity and hyperdorsalization. Although a constitutive activator-type Nanog (Vp16-Nanog, lacking the N terminal) perfectly rescued the MZT defects of MZnanog, it did not rescue the phenotypes resulting from ß-catenin signaling activation. Mechanistically, the N terminal of Nanog directly interacts with T-cell factor (TCF) and interferes with the binding of ß-catenin to TCF, thereby attenuating the transcriptional activity of ß-catenin. Therefore, our study establishes a novel role for Nanog in repressing maternal ß-catenin activity and demonstrates a transcriptional switch between ß-catenin/TCF and Nanog/TCF complexes, which safeguards the embryo from global activation of maternal ß-catenin activity.


Assuntos
Desenvolvimento Embrionário/genética , Proteína Homeobox Nanog/metabolismo , Transativadores/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , beta Catenina/metabolismo , Animais , Padronização Corporal/genética , Núcleo Celular/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Masculino , Mutação/genética , Proteína Homeobox Nanog/química , Proteína Homeobox Nanog/genética , Ligação Proteica , Transporte Proteico , Proteínas Repressoras/metabolismo , Transcrição Genética , Via de Sinalização Wnt/genética , Proteínas de Peixe-Zebra/química , Proteínas de Peixe-Zebra/genética , Zigoto/metabolismo
6.
Nature ; 582(7812): 410-415, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32528178

RESUMO

The body plan of the mammalian embryo is shaped through the process of gastrulation, an early developmental event that transforms an isotropic group of cells into an ensemble of tissues that is ordered with reference to three orthogonal axes1. Although model organisms have provided much insight into this process, we know very little about gastrulation in humans, owing to the difficulty of obtaining embryos at such early stages of development and the ethical and technical restrictions that limit the feasibility of observing gastrulation ex vivo2. Here we show that human embryonic stem cells can be used to generate gastruloids-three-dimensional multicellular aggregates that differentiate to form derivatives of the three germ layers organized spatiotemporally, without additional extra-embryonic tissues. Human gastruloids undergo elongation along an anteroposterior axis, and we use spatial transcriptomics to show that they exhibit patterned gene expression. This includes a signature of somitogenesis that suggests that 72-h human gastruloids show some features of Carnegie-stage-9 embryos3. Our study represents an experimentally tractable model system to reveal and examine human-specific regulatory processes that occur during axial organization in early development.


Assuntos
Padronização Corporal , Gástrula/citologia , Células-Tronco Embrionárias Humanas/citologia , Organoides/citologia , Organoides/embriologia , Somitos/citologia , Somitos/embriologia , Padronização Corporal/genética , Gástrula/embriologia , Gástrula/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Técnicas In Vitro , Organoides/metabolismo , Transdução de Sinais , Somitos/metabolismo , Transcriptoma
7.
Proc Natl Acad Sci U S A ; 117(27): 15712-15723, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32561646

RESUMO

The mechanisms used by embryos to pattern tissues across their axes has fascinated developmental biologists since the founding of embryology. Here, using single-cell technology, we interrogate complex patterning defects and define a Hedgehog (Hh)-fibroblast growth factor (FGF) signaling axis required for anterior mesoderm lineage development during gastrulation. Single-cell transcriptome analysis of Hh-deficient mesoderm revealed selective deficits in anterior mesoderm populations, culminating in defects to anterior embryonic structures, including the pharyngeal arches, heart, and anterior somites. Transcriptional profiling of Hh-deficient mesoderm during gastrulation revealed disruptions to both transcriptional patterning of the mesoderm and FGF signaling for mesoderm migration. Mesoderm-specific Fgf4/Fgf8 double-mutants recapitulated anterior mesoderm defects and Hh-dependent GLI transcription factors modulated enhancers at FGF gene loci. Cellular migration defects during gastrulation induced by Hh pathway antagonism were mitigated by the addition of FGF4 protein. These findings implicate a multicomponent signaling hierarchy activated by Hh ligands from the embryonic node and executed by FGF signals in nascent mesoderm to control anterior mesoderm patterning.


Assuntos
Fator 4 de Crescimento de Fibroblastos/genética , Fator 8 de Crescimento de Fibroblasto/genética , Gastrulação/genética , Proteína GLI1 em Dedos de Zinco/genética , Animais , Padronização Corporal/genética , Linhagem da Célula/genética , Embrião de Galinha , Fatores de Crescimento de Fibroblastos/genética , Gástrula/crescimento & desenvolvimento , Gástrula/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Proteínas Hedgehog/genética , Mesoderma/crescimento & desenvolvimento , Mesoderma/metabolismo , Camundongos , Transdução de Sinais/genética , Análise de Célula Única , Transcriptoma/genética
8.
Genes Dev ; 34(13-14): 965-972, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32467225

RESUMO

Graded transcription factors are pivotal regulators of embryonic patterning, but whether their role changes over time is unclear. A light-regulated protein degradation system was used to assay temporal dependence of the transcription factor Dorsal in dorsal-ventral axis patterning of Drosophila embryos. Surprisingly, the high-threshold target gene snail only requires Dorsal input early but not late when Dorsal levels peak. Instead, late snail expression can be supported by action of the Twist transcription factor, specifically, through one enhancer, sna.distal This study demonstrates that continuous input is not required for some Dorsal targets and downstream responses, such as twist, function as molecular ratchets.


Assuntos
Padronização Corporal/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Fatores de Transcrição/metabolismo , Proteína 1 Relacionada a Twist/metabolismo , Animais , Padronização Corporal/efeitos da radiação , Proteínas de Drosophila/genética , Embrião não Mamífero , Luz , Proteínas Nucleares/genética , Fosfoproteínas/genética , Proteólise/efeitos da radiação , Fatores de Transcrição da Família Snail/metabolismo , Fatores de Transcrição/genética , Proteína 1 Relacionada a Twist/genética
9.
Proc Natl Acad Sci U S A ; 117(21): 11589-11596, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32393634

RESUMO

Organisms have evolved endless morphological, physiological, and behavioral novel traits during the course of evolution. Novel traits were proposed to evolve mainly by orchestration of preexisting genes. Over the past two decades, biologists have shown that cooption of gene regulatory networks (GRNs) indeed underlies numerous evolutionary novelties. However, very little is known about the actual GRN properties that allow such redeployment. Here we have investigated the generation and evolution of the complex wing pattern of the fly Samoaia leonensis We show that the transcription factor Engrailed is recruited independently from the other players of the anterior-posterior specification network to generate a new wing pattern. We argue that partial cooption is made possible because 1) the anterior-posterior specification GRN is flexible over time in the developing wing and 2) this flexibility results from the fact that every single gene of the GRN possesses its own functional time window. We propose that the temporal flexibility of a GRN is a general prerequisite for its possible cooption during the course of evolution.


Assuntos
Drosophilidae , Regulação da Expressão Gênica no Desenvolvimento/genética , Redes Reguladoras de Genes/genética , Pigmentação/genética , Asas de Animais , Animais , Padronização Corporal/genética , Drosophilidae/genética , Drosophilidae/crescimento & desenvolvimento , Proteínas de Insetos/genética , Fatores de Transcrição/genética , Asas de Animais/anatomia & histologia , Asas de Animais/crescimento & desenvolvimento , Asas de Animais/fisiologia
10.
Gene ; 745: 144628, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32224271

RESUMO

microRNAs (miRNAs) are short, endogenous non-coding RNAs that contain approximately 18-22 nucleotides. miRNAs are involved in gene regulation by recognizing and binding the 3'UTR of target gene. In our previous data, miR-430 family showed significant differential expression modes through metamorphosis in Japanese flounder. It was speculated that miR-430a plays a key role in left-right patterning. We predicted the targets of miR-430a and gene ontology (GO) was performed. We speculated miR-430a is involved in the basal molecular function and organ development. In Japanese flounder, sqt as a target of miR-430a was enriched into heart development term. Sqt has been reported to participate in mesendoderm formation and organ development. Cardiac morphogenesis is the first asymmetric development process, which breaks left-right symmetry in bilateria. It was used as a marker to detect L-R asymmetric effects of miR-430a. Overexpression and suppression of miR-430a resulted in abnormal KV (Kupffer's vesicles) development and disordered in nodal-related expression with consequent cardiac laterality. Squint mRNA of Japanese flounder (Posqt) as a target of miR-430a was overexpressed and caused similar phenotype with miR-430a suppression group, such as longer cilia in KV and high range of clmc2 and spaw ectopic expression. Moreover, rescue experiments were performed and suggested that cardiac and KV defections, induced by overexpressing miR-430a, could be rescued by injecting Posqt mRNA. These results suggested that miR-430a regulates the development of left-right asymmetry by targeting sqt in the teleost.


Assuntos
Padronização Corporal/genética , Proteínas de Peixes/genética , Linguado/genética , Regulação da Expressão Gênica no Desenvolvimento , MicroRNAs/metabolismo , Animais , Embrião não Mamífero , Linguado/crescimento & desenvolvimento , Coração/crescimento & desenvolvimento , Metamorfose Biológica , Peixe-Zebra
11.
PLoS Comput Biol ; 16(4): e1007750, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32251432

RESUMO

In multicellular organisms, the timing and placement of gene expression in a developing tissue assigns the fate of each cell in the embryo in order for a uniform field of cells to differentiate into a reproducible pattern of organs and tissues. This positional information is often achieved through the action of spatial gradients of morphogens. Spatial patterns of gene expression are paradoxically robust to variations in morphogen dosage, given that, by definition, gene expression must be sensitive to morphogen concentration. In this work we investigate the robustness of the Dorsal/NF-κB signaling module with respect to perturbations to the dosage of maternally-expressed dorsal mRNA. The Dorsal morphogen gradient patterns the dorsal-ventral axis of the early Drosophila embryo, and we found that an empirical description of the Dorsal gradient is highly sensitive to maternal dorsal dosage. In contrast, we found experimentally that gene expression patterns are highly robust. Although the components of this signaling module have been characterized in detail, how their function is integrated to produce robust gene expression patterns to variations in the dorsal maternal dosage is still unclear. Therefore, we analyzed a mechanistic model of the Dorsal signaling module and found that Cactus, a cytoplasmic inhibitor for Dorsal, must be present in the nucleus for the system to be robust. Furthermore, active Toll, the receptor that dissociates Cactus from Dorsal, must be saturated. Finally, the vast majority of robust descriptions of the system require facilitated diffusion of Dorsal by Cactus. Each of these three recently-discovered mechanisms of the Dorsal module are critical for robustness. These mechanisms synergistically contribute to changing the amplitude and shape of the active Dorsal gradient, which is required for robust gene expression. Our work highlights the need for quantitative understanding of biophysical mechanisms of morphogen gradients in order to understand emergent phenotypes, such as robustness.


Assuntos
Padronização Corporal/genética , Proteínas de Drosophila/genética , Proteínas Nucleares/genética , Fosfoproteínas/genética , Fatores de Transcrição/genética , Animais , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Proteínas de Ligação a DNA/metabolismo , Drosophila/embriologia , Drosophila/genética , Proteínas de Drosophila/metabolismo , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Morfogênese/genética , NF-kappa B/metabolismo , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo
12.
PLoS Genet ; 16(4): e1008652, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32267837

RESUMO

Forward genetic screens remain at the forefront of biology as an unbiased approach for discovering and elucidating gene function at the organismal and molecular level. Past mutagenesis screens targeting maternal-effect genes identified a broad spectrum of phenotypes ranging from defects in oocyte development to embryonic patterning. However, earlier vertebrate screens did not reach saturation, anticipated classes of phenotypes were not uncovered, and technological limitations made it difficult to pinpoint the causal gene. In this study, we performed a chemically-induced maternal-effect mutagenesis screen in zebrafish and identified eight distinct mutants specifically affecting the cleavage stage of development and one cleavage stage mutant that is also male sterile. The cleavage-stage phenotypes fell into three separate classes: developmental arrest proximal to the mid blastula transition (MBT), irregular cleavage, and cytokinesis mutants. We mapped each mutation to narrow genetic intervals and determined the molecular basis for two of the developmental arrest mutants, and a mutation causing male sterility and a maternal-effect mutant phenotype. One developmental arrest mutant gene encodes a maternal specific Stem Loop Binding Protein, which is required to maintain maternal histone levels. The other developmental arrest mutant encodes a maternal-specific subunit of the Minichromosome Maintenance Protein Complex, which is essential for maintaining normal chromosome integrity in the early blastomeres. Finally, we identify a hypomorphic allele of Polo-like kinase-1 (Plk-1), which results in a male sterile and maternal-effect phenotype. Collectively, these mutants expand our molecular-genetic understanding of the maternal regulation of early embryonic development in vertebrates.


Assuntos
Divisão Celular/genética , Desenvolvimento Embrionário/genética , Herança Materna/genética , Mutação , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Alelos , Animais , Blástula/citologia , Blástula/embriologia , Blástula/metabolismo , Padronização Corporal/genética , Núcleo Celular , Citocinese/genética , Feminino , Infertilidade Masculina/genética , Masculino , Mutagênese , Fenótipo , Proteínas de Peixe-Zebra/genética
13.
Development ; 147(6)2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32179574

RESUMO

Precise temporal coordination of signaling processes is pivotal for cellular differentiation during embryonic development. A vast number of secreted molecules are produced and released by cells and tissues, and travel in the extracellular space. Whether they induce a signaling pathway and instruct cell fate, however, depends on a complex network of regulatory mechanisms, which are often not well understood. The conserved bilateral left-right asymmetrically formed habenulae of the zebrafish are an excellent model for investigating how signaling control facilitates the generation of defined neuronal populations. Wnt signaling is required for habenular neuron type specification, asymmetry and axonal connectivity. The temporal regulation of this pathway and the players involved have, however, have remained unclear. We find that tightly regulated temporal restriction of Wnt signaling activity in habenular precursor cells is crucial for the diversity and asymmetry of habenular neuron populations. We suggest a feedback mechanism whereby the tumor suppressor Wnt inhibitory factor Wif1 controls the Wnt dynamics in the environment of habenular precursor cells. This mechanism might be common to other cell types, including tumor cells.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Padronização Corporal/genética , Habenula/embriologia , Neurogênese/genética , Neurônios/fisiologia , Proteínas Repressoras/fisiologia , Via de Sinalização Wnt/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Animais Geneticamente Modificados , Encéfalo/citologia , Encéfalo/embriologia , Diferenciação Celular/genética , Linhagem da Célula/genética , Dominância Cerebral/genética , Embrião não Mamífero , Habenula/metabolismo , Neurogênese/fisiologia , Neurônios/citologia , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
14.
Development ; 147(5)2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32161062

RESUMO

The modulation of mechanical tension is important for sculpturing tissues during animal development, yet how mechanical tension is controlled remains poorly understood. In Drosophila wing discs, the local reduction of mechanical tension at basal cell edges results in basal relaxation and the formation of an epithelial fold. Here, we show that Wingless, which is expressed next to this fold, promotes basal cell edge tension to suppress the formation of this fold. Ectopic expression of Wingless blocks fold formation, whereas the depletion of Wingless increases fold depth. Moreover, local depletion of Wingless in a region where Wingless signal transduction is normally high results in ectopic fold formation. The depletion of Wingless also results in decreased basal cell edge tension and basal cell area relaxation. Conversely, the activation of Wingless signal transduction leads to increased basal cell edge tension and basal cell area constriction. Our results identify the Wingless signal transduction pathway as a crucial modulator of mechanical tension that is important for proper wing disc morphogenesis.


Assuntos
Padronização Corporal/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/embriologia , Morfogênese/genética , Asas de Animais/embriologia , Proteína Wnt1/genética , Animais , Padronização Corporal/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/genética , Transdução de Sinais/genética , Estresse Mecânico
15.
Development ; 147(3)2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32014863

RESUMO

Cardiopharyngeal mesoderm (CPM) gives rise to muscles of the head and heart. Using genetic lineage analysis in mice, we show that CPM develops into a broad range of pharyngeal structures and cell types encompassing musculoskeletal and connective tissues. We demonstrate that CPM contributes to medial pharyngeal skeletal and connective tissues associated with both branchiomeric and somite-derived neck muscles. CPM and neural crest cells (NCC) make complementary mediolateral contributions to pharyngeal structures, in a distribution established in the early embryo. We further show that biallelic expression of the CPM regulatory gene Tbx1, haploinsufficient in 22q11.2 deletion syndrome patients, is required for the correct patterning of muscles with CPM-derived connective tissue. Our results suggest that CPM plays a patterning role during muscle development, similar to that of NCC during craniofacial myogenesis. The broad lineage contributions of CPM to pharyngeal structures provide new insights into congenital disorders and evolution of the mammalian pharynx.


Assuntos
Tecido Conjuntivo/embriologia , Desenvolvimento Muscular/genética , Faringe/embriologia , Somitos/fisiologia , Animais , Padronização Corporal/genética , Linhagem da Célula/genética , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Camundongos Transgênicos , Crista Neural/metabolismo , Faringe/citologia , Somitos/citologia , Proteínas com Domínio T/metabolismo
16.
Development ; 147(6)2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32098764

RESUMO

Neocortex development during embryonic stages requires the precise control of mRNA metabolism. Human antigen R (HuR) is a well-studied mRNA-binding protein that regulates mRNA metabolism, and it is highly expressed in the neocortex during developmental stages. Deletion of HuR does not impair neural progenitor cell proliferation or differentiation, but it disturbs the laminar structure of the neocortex. We report that HuR is expressed in postmitotic projection neurons during mouse brain development. Specifically, depletion of HuR in these neurons led to a mislocalization of CDP+ neurons in deeper layers of the cortex. Time-lapse microscopy showed that HuR was required for the promotion of cell motility in migrating neurons. PCR array identified profilin 1 (Pfn1) mRNA as a major binding partner of HuR in neurons. HuR positively mediated the stability of Pfn1 mRNA and influenced actin polymerization. Overexpression of Pfn1 successfully rescued the migration defects of HuR-deleted neurons. Our data reveal a post-transcriptional mechanism that maintains actin dynamics during neuronal migration.


Assuntos
Movimento Celular , Proteína Semelhante a ELAV 1/fisiologia , Neurônios/fisiologia , RNA Mensageiro/metabolismo , Animais , Padronização Corporal/genética , Movimento Celular/genética , Células Cultivadas , Embrião de Mamíferos , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células-Tronco Neurais/fisiologia , Neurogênese/genética , Gravidez , Profilinas/fisiologia , Processamento Pós-Transcricional do RNA/genética
17.
Development ; 147(6)2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32094115

RESUMO

Segmentation of the vertebrate hindbrain leads to the formation of rhombomeres, each with a distinct anteroposterior identity. Specialised boundary cells form at segment borders that act as a source or regulator of neuronal differentiation. In zebrafish, there is spatial patterning of neurogenesis in which non-neurogenic zones form at boundaries and segment centres, in part mediated by Fgf20 signalling. To further understand the control of neurogenesis, we have carried out single cell RNA sequencing of the zebrafish hindbrain at three different stages of patterning. Analyses of the data reveal known and novel markers of distinct hindbrain segments, of cell types along the dorsoventral axis, and of the transition of progenitors to neuronal differentiation. We find major shifts in the transcriptome of progenitors and of differentiating cells between the different stages analysed. Supervised clustering with markers of boundary cells and segment centres, together with RNA-seq analysis of Fgf-regulated genes, has revealed new candidate regulators of cell differentiation in the hindbrain. These data provide a valuable resource for functional investigations of the patterning of neurogenesis and the transition of progenitors to neuronal differentiation.


Assuntos
Padronização Corporal/genética , Rombencéfalo/embriologia , Rombencéfalo/metabolismo , Transcriptoma/fisiologia , Peixe-Zebra , Animais , Animais Geneticamente Modificados , Atlas como Assunto , Diferenciação Celular/genética , Embrião não Mamífero , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Redes Reguladoras de Genes , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Neurônios/citologia , Neurônios/fisiologia , Análise de Célula Única/métodos , Distribuição Tecidual , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
18.
Curr Biol ; 30(2): 254-263.e2, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-31928872

RESUMO

Regeneration involves regulating tissue proportionality across considerable size ranges through unknown mechanisms. In planarians, which scale reversibly over 40× through regeneration, we identify the Striatin-interacting phosphatase and kinase (STRIPAK) complex as a potent negative regulator of axis length. Inhibition of two proteins in the STRIPAK complex, mob4 and striatin, dramatically increased posterior length, through expansion of a posterior wnt1+ signaling center within midline muscle cells. wnt1 was required for tail expansion after mob4 inhibition and dynamically reestablishes proportionality after amputation in normal animals, indicating STRIPAK represses Wnt signaling for scaling. Regulation of wnt1 expansion was stem cell dependent, demonstrating that control of signaling-center production through stem cell differentiation underlies proportional growth in adult regenerative tissue.


Assuntos
Padronização Corporal/genética , Diferenciação Celular/genética , Proteínas de Helminto/genética , Planárias/genética , Células-Tronco/citologia , Via de Sinalização Wnt/fisiologia , Animais , Proteínas de Helminto/metabolismo , Planárias/citologia , Planárias/crescimento & desenvolvimento , Planárias/metabolismo
19.
Sci Adv ; 6(2): eaax9852, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31950080

RESUMO

Holoprosencephaly (HPE) is a congenital forebrain defect often associated with embryonic lethality and lifelong disabilities. Currently, therapeutic and diagnostic options are limited by lack of knowledge of potential disease-causing mutations. We have identified a new mutation in the PRDM15 gene (C844Y) associated with a syndromic form of HPE in multiple families. We demonstrate that C844Y is a loss-of-function mutation impairing PRDM15 transcriptional activity. Genetic deletion of murine Prdm15 causes anterior/posterior (A/P) patterning defects and recapitulates the brain malformations observed in patients. Mechanistically, PRDM15 regulates the transcription of key effectors of the NOTCH and WNT/PCP pathways to preserve early midline structures in the developing embryo. Analysis of a large cohort of patients with HPE revealed potentially damaging mutations in several regulators of both pathways. Our findings uncover an unexpected link between NOTCH and WNT/PCP signaling and A/P patterning and set the stage for the identification of new HPE candidate genes.


Assuntos
Polaridade Celular , Proteínas de Ligação a DNA/genética , Holoprosencefalia/genética , Mutação com Perda de Função/genética , Receptores Notch/metabolismo , Fatores de Transcrição/genética , Via de Sinalização Wnt , Animais , Padronização Corporal/genética , Encéfalo/anormalidades , Encéfalo/embriologia , Polaridade Celular/genética , Estudos de Coortes , Embrião de Mamíferos/anormalidades , Embrião de Mamíferos/metabolismo , Feminino , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos , Placa Neural/metabolismo , Gravidez , Transcrição Genética , Dedos de Zinco
20.
Development ; 147(3)2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31964774

RESUMO

Sonic hedgehog (Shh) signal transduction specifies ventral cell fates in the neural tube and is mediated by the Gli transcription factors that play both activator (GliA) and repressor (GliR) roles. Cilia are essential for Shh signal transduction and the ciliary phosphatidylinositol phosphatase Inpp5e is linked to Shh regulation. In the course of a forward genetic screen for recessive mouse mutants, we identified a functional null allele of inositol polyphosphate-5-phosphatase E (Inpp5e), ridge top (rdg), with expanded ventral neural cell fates at E10.5. By E12.5, Inpp5erdg/rdg embryos displayed normal neural patterning and this correction over time required Gli3, the predominant repressor in neural patterning. Inpp5erdg function largely depended on the presence of cilia and on smoothened, the obligate transducer of Shh signaling, indicating that Inpp5e functions within the cilium to regulate the pathway. These data indicate that Inpp5e plays a more complicated role in Shh signaling than previously appreciated. We propose that Inpp5e attenuates Shh signaling in the neural tube through regulation of the relative timing of GliA and GliR production, which is important in understanding how the duration of Shh signaling regulates neural tube patterning.


Assuntos
Cílios/metabolismo , Proteínas Hedgehog/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Transdução de Sinais/genética , Alelos , Animais , Padronização Corporal/genética , Embrião de Mamíferos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Tubo Neural/metabolismo , Monoéster Fosfórico Hidrolases/genética , Receptor Smoothened/genética , Receptor Smoothened/metabolismo , Proteína Gli3 com Dedos de Zinco/genética , Proteína Gli3 com Dedos de Zinco/metabolismo
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