RESUMO
The sea urchin larval skeleton offers a simple model for formation of developmental patterns. The calcium carbonate skeleton is secreted by primary mesenchyme cells (PMCs) in response to largely unknown patterning cues expressed by the ectoderm. To discover novel ectodermal cues, we performed an unbiased RNA-Seq-based screen and functionally tested candidates; we thereby identified several novel skeletal patterning cues. Among these, we show that SLC26a2/7 is a ventrally expressed sulfate transporter that promotes a ventral accumulation of sulfated proteoglycans, which is required for ventral PMC positioning and skeletal patterning. We show that the effects of SLC perturbation are mimicked by manipulation of either external sulfate levels or proteoglycan sulfation. These results identify novel skeletal patterning genes and demonstrate that ventral proteoglycan sulfation serves as a positional cue for sea urchin skeletal patterning.
Assuntos
Padronização Corporal/genética , Proteoglicanas/metabolismo , Ouriços-do-Mar/embriologia , Ouriços-do-Mar/genética , Análise de Sequência de RNA/métodos , Sulfatos/metabolismo , Animais , Padronização Corporal/efeitos dos fármacos , Proteínas de Transporte de Cátions/metabolismo , Diferenciação Celular/efeitos dos fármacos , Ectoderma/efeitos dos fármacos , Ectoderma/enzimologia , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Mesoderma/citologia , Modelos Biológicos , Níquel/toxicidade , Ouriços-do-Mar/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Recently, we demonstrated that the microRNA 424(322)/503 [miR-424(322)/503] cluster is transcriptionally controlled by transforming growth factor ß (TGF-ß) in the mammary epithelium. Induction of this microRNA cluster impacts mammary epithelium fate by regulating apoptosis and insulin-like growth factor 1 (IGF1) signaling. Here, we expanded our finding to demonstrate that miR-424(322)/503 is an integral component of the cell cycle arrest mediated by TGF-ß. Mechanistically, we showed that after TGF-ß exposure, increased levels of miR-424(322)/503 reduce the expression of the cell cycle regulator CDC25A. miR-424(322)/503-dependent posttranscriptional downregulation of CDC25A cooperates with previously described transcriptional repression of the CDC25A promoter and proteasome-mediated degradation to reduce the levels of CDC25A expression and to induce cell cycle arrest. We also provide evidence that the TGF-ß/miR-424(322)/503 axis is part of the mechanism that regulates the proliferation of hormone receptor-positive (HR(+)) mammary epithelial cells in vivo.
Assuntos
Glândulas Mamárias Humanas/crescimento & desenvolvimento , MicroRNAs/genética , Fator de Crescimento Transformador beta/metabolismo , Fosfatases cdc25/biossíntese , Animais , Apoptose/genética , Linhagem Celular , Proliferação de Células/genética , Regulação para Baixo , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular/genética , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/crescimento & desenvolvimento , Glândulas Mamárias Humanas/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/biossíntese , Regiões Promotoras Genéticas , Pirazóis/farmacologia , Pirróis/farmacologia , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Transcrição Gênica , Fator de Crescimento Transformador beta/antagonistas & inibidores , Fosfatases cdc25/genéticaRESUMO
Chromatin regulators have recently emerged as key players in the control of tissue development and tumorigenesis. One specific chromatin regulator, the Polycomb complex, has been shown to regulate the identity of embryonic stem cells, but its role in controlling fates of multipotent progenitors in developing tissues is still largely unknown. Recent findings have revealed that this complex plays a critical role in control of skin stem cell renewal and differentiation. Moreover, the expression of Polycomb complex components is often aberrant in skin diseases, including skin cancers. This review will detail recent findings on Polycomb control of skin and highlight critical unknown questions.