RESUMO
During tissue morphogenesis and differentiation, cells must self-renew while contemporaneously generating daughters that contribute to the growing tissue. How tissues achieve this precise balance between proliferation and differentiation is, in most instances, poorly understood. This is in part due to the difficulties in dissociating the mechanisms that underlie tissue patterning from those that regulate proliferation. In the migrating posterior lateral line primordium (PLLP), proliferation is predominantly localised to the leading zone. As cells emerge from this zone, they periodically organise into rosettes that subsequently dissociate from the primordium and differentiate as neuromasts. Despite this reiterative loss of cells, the primordium maintains its size through regenerative cell proliferation until it reaches the tail. In this study, we identify a null mutation in the Wnt-pathway transcription factor Lef1 and show that its activity is required to maintain proliferation in the progenitor pool of cells that sustains the PLLP as it undergoes migration, morphogenesis and differentiation. In absence of Lef1, the leading zone becomes depleted of cells during its migration leading to the collapse of the primordium into a couple of terminal neuromasts. We show that this behaviour resembles the process by which the PLLP normally ends its migration, suggesting that suppression of Wnt signalling is required for termination of neuromast production in the tail. Our data support a model in which Lef1 sustains proliferation of leading zone progenitors, maintaining the primordium size and defining neuromast deposition rate.
Assuntos
Proliferação de Células , Homeostase/genética , Sistema da Linha Lateral/embriologia , Fatores de Transcrição/fisiologia , Proteínas Wnt/fisiologia , Proteínas de Peixe-Zebra/fisiologia , beta Catenina/fisiologia , Nadadeiras de Animais/embriologia , Nadadeiras de Animais/crescimento & desenvolvimento , Nadadeiras de Animais/metabolismo , Animais , Animais Geneticamente Modificados , Padronização Corporal/genética , Diferenciação Celular/genética , Embrião não Mamífero , Homeostase/fisiologia , Sistema da Linha Lateral/metabolismo , Masculino , Morfogênese/genética , Morfogênese/fisiologia , Mutação/fisiologia , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , beta Catenina/genética , beta Catenina/metabolismoRESUMO
Reactive oxygen species (ROS) function in a range of physiological processes such as growth, metabolism and signaling, and also have a pathological role. Recent research highlighted the requirement for ROS generated by dual oxidase (DUOX) in host-defence responses in innate immunity and inflammatory disorders such as inflammatory bowel disease (IBD), but in vivo evidence to support this has, to date, been lacking. In order to investigate the involvement of Duox in gut immunity, we characterized the zebrafish ortholog of the human DUOX genes. Zebrafish duox is highly expressed in intestinal epithelial cells. Knockdown of Duox impaired larval capacity to control enteric Salmonella infection.