1.19Hormonal controls of zebrafish post-embryonic melanocyte development

描述（由申请人提供）：这项工作的长期目标是确定脊椎动物胚胎后发育所需的遗传、细胞和内分泌机制。这一建议的重点是斑马鱼的变态，发生在受精后12-28天之间，类似于人类胎儿和新生儿的发育。在斑马鱼蜕变过程中发生的许多变化中，胚胎/早期幼虫的色素模式转变为成虫的色素模式，这一过程依赖于潜在干细胞的募集，并可能受激素控制。甲状腺激素（TH）在两栖动物和哺乳动物胚胎后发育过程中起着至关重要的作用。目的1将测试TH信号在斑马鱼体细胞和色素模式变态中的作用。这将通过使用转基因细胞系在整个鱼或特定细胞系的特定时间阻断TH信号来实现。为了研究全局内分泌介质如何影响局部细胞的规范和形态发生过程，Aim 2将测试TH信号和Wnt信号之间的相互作用，这两种信号已知对色素细胞的发育和干细胞的自我更新至关重要。这些实验将采用转基因系和其他方法来抑制或刺激这些途径，并测定途径的活性和表型结果。最后，可能还有许多其他的胚胎后发育介质，为了识别这些介质，目的3将构建一个前向遗传筛选，以筛选那些不能完全变形或在特定性状和细胞类型的变形中有缺陷的突变体。该筛选将采用基因断裂载体和转座子介导的插入突变，允许有效地识别和分析受影响的位点。这些努力将为脊椎动物胚胎后发育的机制提供重要的新见解。*脊椎动物在胚胎后期经历了广泛的变化，其中许多变化依赖于从自我更新的干细胞群体中招募分化的后代。因此，阐明干细胞和祖细胞更新和分化所需的基因、细胞行为和激素机制对于理解人类健康和许多疾病综合征和癌症都很重要。

DESCRIPTION (provided by applicant): The long-term objective of this work is to identify genetic, cellular, and endocrine mechanisms required for post-embryonic development in vertebrates. This proposal focuses on metamorphosis of the zebrafish, which occurs between 12-28 days post-fertilization, and is analogous to human fetal and neonatal development. Among the many changes that occur during zebrafish metamorphosis is the transformation of an embryonic/early larval pigment pattern into that of the adult, a process that depends on the recruitment of latent stem cells and is likely under hormonal control. As thyroid hormone (TH) is critical for amphibian metamorphosis as well as mammalian post-embryonic development. Aim 1 will test roles for TH signaling in zebrafish somatic and pigment pattern metamorphosis. This will be accomplished using transgenic lines to block TH signals at specific times either throughout the fish or in specific cell lineages. To examine how global endocrine mediators effect local cellular processes of specification and morphogenesis, Aim 2 will test for interactions between TH signals and Wnt signals that are known to be critical for pigment cell 'development as well as stem cell self-renewal. These experiments will employ transgenic lines and other approaches to inhibit or stimulate these pathways and assay pathway activity and phenotypic outcomes. Finally, there may be many additional mediators of post-embryonic development, and to identify these, aim 3 will constitute a forward genetic screen for mutants that fail to undergo metamorphosis either entirely or have defects in the metamorphosis of specific traits and cell types. This screen will employ gene-breaking vectors and transposon-mediated insertional mutagenesis, allowing the efficient identification and analysis of affected loci. Together these efforts will provide significant new insights into the mechanisms of vertebrate post-embryonic development. *Vertebrates undergo extensive changes during postembryonic stages and many of these changes depend on the recruitment of differentiated progeny from self-renewing stem cell populations. Elucidating the genes, cell behaviors and hormonal mechanisms required for stem and progenitor cell renewal and differentiation is therefore important for understanding both human health and many disease syndromes and cancers.