Imaging the formation of an hematopoietic niche

干细胞对于组织的动态平衡是必不可少的，并且通常定位于控制其组织内环境的特定的小生境。 功能。通过这种方式，利基环境几乎控制着干细胞动力学的所有方面，而干细胞动力学是组织必不可少的特性。 维修。最近的研究表明，精确的蜂窝架构对于利基市场来说很重要 与它控制的干细胞进行忠实的交流。一个主要问题是，该领域还没有完全理解 组织中的生态位最初是如何形成的，也不是导致一组细胞产生 一个有效的利基市场，也不知道该组织如何影响干细胞调控。我们的实验室最近取得了重大进展 这类问题的研究进展对睾丸的影响很大。特别是，我们使用实时成像来定义 果蝇性腺生态位组装的动态步骤。这些观察结果直接导致了一系列 实验揭示了对这个利基的组装的机械理解。 昆虫的造血与我们的先天免疫系统非常相似，使用了几个重要的保守因素 用于指定巨噬细胞样细胞和抗微生物产生细胞。这些免疫细胞的祖细胞是 由一个名为后部信号中心(PSC)的利基控制。其他人使用固定胚胎和 终点分析表明，PSC是从一个细胞团衍生出来的，该细胞团必须迁移以获得其应有的功能 定位并开始作为一个利基市场发挥作用。支持利基细胞如何导航到正确的位置和组装 进入一个实用的利基市场是未知的。我们建议在这里开发工具来解决这些问题。 我们将建立工具，在早期对PSC进行谱系标记-足以在体内可视化其构建。这 包括构建转基因品系，使其具有空间和时间光遗传控制能力。 标记和实时可视化。这些相同的工具将使后续实验能够揭示 生态位组装的潜在机制。我们还将描述PSC细胞的转录图景 目的：寻找有助于研究PSC形态发生的新标记。 总的来说，我们的方法应该为我们提供试剂和初步结果，以支持 直接涉及基本机制的实质性、长期赠款提案。

Stem cells are necessary for tissue homeostasis, and are often localized to specialized niches that control their function. In this manner, niches control virtually all aspects of stem cell dynamics, properties essential to tissue maintenance. Recent work has shown that precise cellular architecture is important in order for a niche to communicate with fidelity to the stem cells it controls. A major issue is that the field does not fully understand how niches are initially formed in a tissue, nor the key cell biological steps that cause a group of cells to create an effective niche, nor how that organization impacts stem cell regulation. Our lab recently made significant advances on such questions working on the testis niche. In particular we used live-imaging to define the dynamic steps in Drosophila gonadal niche assembly. These observations led directly to a series of experiments revealing a mechanistic understanding of the assembly of this niche. Insect hematopoiesis closely parallels our innate immune system, using several conserved factors important for specifying macrophage-like and anti-microbial-producing cells. The progenitors for these immune cells are controlled by a niche called the Posterior Signaling Center (PSC). Work of others using fixed embryos and end-point analysis showed that the PSC is derived from a cell cluster that must migrate to take up its proper position and begin functional as a niche. How the pro-niche cells navigate to the correct position and assemble into a functional niche is unknown. We propose here to develop tools to address these questions. We will build tools to lineage-label the PSC at an early-enough stage to visualize its construction in vivo. This includes the construction of transgenic lines that should confer spatial and temporal optogenetic control for labeling and real-time visualization. These same tools would enable follow-up experiments to expore the mechanisms underlying niche assembly. We will additionally profile the transcriptional landscape of PSC cells in order to identify new markers aiding investigation of PSC morphogenesis. Collectively, our approaches should provide us with the reagents and preliminary results to support a substantive, longer-term grant proposal addressing underlying mechanisms directly.