Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros

Base de dados
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Dev Biol ; 397(1): 45-55, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25446538

RESUMO

The mechanisms regulating cell division during development of the mouse pre-implantation embryo are poorly understood. We have investigated whether bone morphogenetic protein (BMP) signaling is involved in controlling cell cycle during mouse pre-implantation development. We mapped and quantitated the dynamic activities of BMP signaling through high-resolution immunofluorescence imaging combined with a 3D segmentation method. Immunostaining for phosphorylated Smad1/5/8 shows that BMP signaling is activated in mouse embryos as early as the 4-cell stage, and becomes spatially restricted by late blastocyst stage. Perturbation of BMP signaling in preimplantation mouse embryos, whether by treatment with a small molecule inhibitor, with Noggin protein, or by overexpression of a dominant-negative BMP receptor, indicates that BMPs regulate cell cleavage up to the morula stage. These results indicate that BMP signaling is active during mouse pre-implantation development and is required for cell cleavage in preimplantation mouse embryos.


Assuntos
Blastocisto/fisiologia , Proteínas Morfogenéticas Ósseas/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Animais , Proteínas de Transporte/metabolismo , Divisão Celular , Células Cultivadas , Desenvolvimento Embrionário/genética , Células-Tronco Embrionárias/citologia , Feminino , Genes Dominantes , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Microscopia de Fluorescência , Fosforilação , Transdução de Sinais , Proteína Smad1/fisiologia , Proteína Smad5/fisiologia , Proteína Smad8/fisiologia , Fatores de Tempo
2.
PLoS One ; 7(9): e42566, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22984405

RESUMO

Cellular responses to Bmp ligands are regulated at multiple levels, both extracellularly and intracellularly. Therefore, the presence of these growth factors is not an accurate indicator of Bmp signaling activity. While a common approach to detect Bmp signaling activity is to determine the presence of phosphorylated forms of Smad1, 5 and 8 by immunostaining, this approach is time consuming and not quantitative. In order to provide a simpler readout system to examine the presence of Bmp signaling in developing animals, we developed BRE-gal mouse embryonic stem cells and a transgenic mouse line that specifically respond to Bmp ligand stimulation. Our reporter identifies specific transcriptional responses that are mediated by Smad1 and Smad4 with the Schnurri transcription factor complex binding to a conserved Bmp-Responsive Element (BRE), originally identified among Drosophila, Xenopus and human Bmp targets. Our BRE-gal mES cells specifically respond to Bmp ligands at concentrations as low as 5 ng/ml; and BRE-gal reporter mice, derived from the BRE-gal mES cells, show dynamic activity in many cellular sites, including extraembryonic structures and mammary glands, thereby making this a useful scientific tool.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Transcrição Gênica , Animais , Sequência de Bases , Sítios de Ligação , Proteínas Morfogenéticas Ósseas/farmacologia , Linhagem Celular , Embrião de Mamíferos/citologia , Embrião de Mamíferos/efeitos dos fármacos , Embrião de Mamíferos/metabolismo , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Embrionárias/metabolismo , Feminino , Gastrulação/efeitos dos fármacos , Gastrulação/genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Genes Reporter/genética , Humanos , Ligantes , Camundongos , Camundongos Transgênicos , Dados de Sequência Molecular , Gravidez , Linha Primitiva/efeitos dos fármacos , Linha Primitiva/metabolismo , Ligação Proteica/efeitos dos fármacos , Elementos de Resposta/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteínas Smad/metabolismo , Transcrição Gênica/efeitos dos fármacos
3.
PLoS One ; 7(9): e44009, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22984456

RESUMO

Insights into Bone morphogenetic protein (Bmp) functions during forebrain development have been limited by a lack of Bmp signaling readouts. Here we used a novel Bmp signaling reporter ("BRE-gal" mice) to study Bmp signaling in the dorsal telencephalon. At early stages, BRE-gal expression was restricted to the dorsal telencephalic midline. At later stages, strong BRE-gal expression occurred in neurons of the marginal zone and dentate gyrus. Comparisons to nuclear phospho-Smad1/5/8 (pSmad) and Msx1 indicated that BRE-gal expression occurred exclusively in neural cells with high-level Bmp signaling. BRE-gal responsiveness to Bmps was confirmed in reporter-negative cortical cells cultured with Bmp4, and both in vivo and in vitro, BRE-gal expression was switch-like, or ultrasensitive. In the early dorsal telencephalon, BRE-gal expression negatively correlated with the cortical selector gene Lhx2, indicating a BRE-gal expression border that coincides with the cortex-hem boundary. However, in Lhx2 null chimeras, neither BRE-gal nor nuclear pSmad increases were observed in ectopic hem cells. These findings establish BRE-gal as an ultrasensitive reporter of Bmp signaling in the dorsal telencephalon, imply that hem fate can be specified at different Bmp signaling intensities, and suggest that Lhx2 primarily regulates the responses to--rather than the intensity of--Bmp signaling in dorsal telencephalic cells.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Linhagem da Célula , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Genes Reporter/genética , Transdução de Sinais , Animais , Animais Recém-Nascidos , Proteína Morfogenética Óssea 4/metabolismo , Proteínas Morfogenéticas Ósseas/genética , Diferenciação Celular , Córtex Cerebral/metabolismo , Hipocampo/citologia , Hipocampo/embriologia , Fator de Transcrição MSX1/metabolismo , Camundongos , Neurônios/citologia , Neurônios/metabolismo , Especificidade de Órgãos , Fosforilação , Proteínas Smad/metabolismo , beta-Galactosidase/metabolismo
4.
J Exp Zool B Mol Dev Evol ; 308(5): 679-91, 2007 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-17724731

RESUMO

Transcription factor AP2 (Tfap2) genes play essential roles in development of the epidermis and migratory cells of the neural crest (NC) in vertebrate embryos. These transcriptional activators are among the earliest genes expressed in the ectoderm and specify fates within the epidermis/crest through both direct and indirect mechanisms. The Tfap2 family arose from a single ancestral gene in a chordate ancestor that underwent gene duplication to give up to five family members in living vertebrates. This coincided with the acquisition of important roles in NC development by Tfap2 genes suggesting that this gene family was important in ectodermal evolution and possibly in the origin of NC. Here, we show that a zebrafish tfap2c is expressed in the nonneural ectoderm during early development and functions redundantly with tfap2a in NC specification. In zebrafish embryos depleted of both tfap2a and tfap2c, NC cells are virtually eliminated. Cell transplantation experiments indicate that tfap2c functions cell-autonomously in NC specification. Cells of the enveloping layer, which forms a temporary skin layer surrounding the ectoderm, also fail to differentiate or to express appropriate keratins in tfap2c deficient embryos. The role of Tfap2 genes in epidermal and NC development is considered here in the broader context of ectodermal evolution. Distinct, tissue-specific functions for Tfap2 genes in different vertebrates may reflect subfunctionalisation of an ancestral gene that consequently led to the gain of novel roles for different subfamily members in patterning the epidermis and NC.


Assuntos
Ectoderma/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/genética , Crista Neural/embriologia , Fator de Transcrição AP-2/fisiologia , Peixe-Zebra/embriologia , Sequência de Aminoácidos , Animais , Cordados/genética , Primers do DNA/química , Embrião não Mamífero/embriologia , Perfilação da Expressão Gênica/veterinária , Queratinas/biossíntese , Queratinas/efeitos dos fármacos , Dados de Sequência Molecular , Família Multigênica/fisiologia , Filogenia , Análise de Sequência de Proteína/veterinária , Fator de Transcrição AP-2/biossíntese , Fator de Transcrição AP-2/genética , Fator de Transcrição AP-2/farmacologia , Proteínas de Xenopus/farmacologia , Proteínas de Peixe-Zebra/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA