Elucidating the role of Ftz-f1 as a mediator of steroid hormone-dependent activity in stem cells and their progeny

项目摘要 细胞重编程的最新进展引起了人们对干细胞应用的极大兴趣。 细胞再生疗法，以取代受损或丢失的细胞。干细胞整合了多种 内在和外在的线索，以维持他们的命运和增殖能力。重要的是，这些线索 包括类固醇激素，其在儿童生长和发育、怀孕期间波动， 疾病和核激素受体，它们接收类固醇信号以调节生理 体内平衡对干细胞如何响应人体生理变化的基本认识 因此，在临床治疗中增加干细胞的使用是必要的先决条件。像 其他核激素受体信号通路，昆虫类固醇激素蜕皮激素已知， 引起依赖于环境的细胞反应;然而，这些反应是如何发生的在很大程度上是未知的。 办妥了一批核激素受体Ftz-f1是蜕皮激素的靶点，但它也是蜕皮激素分泌所必需的。 在胚胎和哺乳动物中，其他蜕皮激素靶点（即E74和E75）的最大转录反应 幼虫组织这表明Ftz-f1活性启动一些细胞对蜕皮激素的反应， 调节特定的转录途径。尽管近25年来对突变等位基因的鉴定 迄今为止，还没有研究涉及Ftz-f1在卵巢中的功能。我们的研究将测试 Ftz-f1作为卵巢中蜕皮激素信号传导的能力因子的中心假设。 果蝇卵巢中的生殖系干细胞（GSC）非常适合这些研究，因为 他们容易接近的解剖位置，对类固醇激素的敏感性，以及 基因和实验技术。我们的研究不仅会揭示关于 FTZ-F1在干细胞和生殖中的功能，但也可以作为一个新的范例， 背景依赖性类固醇激素体内信号传导研究。在我新的独立实验室里，我们将利用 果蝇遗传突变体和体内细胞特异性基因敲低，以调查是否和如何 ftz-f1调节GSC及其后代，并测试ftz-f1是否引发蜕皮激素特异性细胞 信号在目的1中，我们将研究ftz-f1在GSC分化及其分化中的作用。 后代在目标2中，我们将研究ftz-f1是否控制GSC的细胞周期及其 后代在目标3中，我们将使用遗传互作实验来确定ftz-f1是否 在功能上与蜕皮激素信号传导相互作用。鉴于果蝇和人类的相似性 类固醇激素信号，我们的研究将有助于阐明如何核激素受体差异 在体内调节环境依赖性转录途径以控制干细胞功能。

PROJECT SUMMARY Recent advances in cell reprogramming have raised considerable interest in the use of stem cells for regenerative therapies to replace damaged or lost cells. Stem cells integrate a variety of intrinsic and extrinsic cues to maintain their fate and proliferative capacity. Importantly, these cues include steroid hormones, which fluctuate during childhood growth and development, pregnancy, and disease, and nuclear hormone receptors, which receive steroid signals to regulate physiological homeostasis. A basic understanding of how stem cells respond to changes in human physiology is therefore a necessary prerequisite to the increased use of stem cells in clinical therapy. Like other nuclear hormone receptor signaling pathways, the insect steroid hormone ecdysone is known to elicit context-dependent cellular responses; however, it is largely unknown how these responses are achieved. The nuclear hormone receptor Ftz-f1 is an ecdysone target, but it is also required for the maximal transcriptional response of other ecdysone targets (namely, E74 and E75) in embryonic and larval tissues. This suggests that Ftz-f1 activity primes some cells to respond to ecdysone by up- regulating a specific transcriptional pathway. Despite the identification of mutant alleles nearly 25 years ago, no studies to date have addressed the function of Ftz-f1 in the ovary. Our studies will test the central hypothesis that Ftz-f1 acts as a competence factor for ecdysone signaling in the ovary. Germline stem cells (GSCs) in the Drosophila melanogaster ovary are well-suited for these studies, due to their easily accessible anatomical location, sensitivity to steroid hormones, and the availability of genetic and experimental techniques. Our studies will not only reveal important new information about the function of ftz-f1 in stem cells and reproduction, but can also serve as a novel paradigm for the study of context-dependent steroid hormone signaling in vivo. In my new independent lab, we will utilize Drosophila genetic mutants and in vivo cell-specific gene knockdown to investigate whether and how ftz-f1 regulates GSCs and their progeny, and test whether ftz-f1 primes specific cells for ecdysone signaling. In Aim 1, we will examine the role of ftz-f1 in the differentiation of GSCs and their progeny. In Aim 2, we will investigate whether ftz-f1 controls the cell cycle in GSCs and their progeny. In Aim 3, we will use genetic interaction experiments to determine whether ftz-f1 functionally interacts with ecdysone signaling. Given the similarity between Drosophila and human steroid hormone signaling, our study will help elucidate how nuclear hormone receptors differentially regulate context-dependent transcriptional pathways in vivo to control stem cell function.