Regulating transcription of the key pulmonary neuroendocrine lineage driver ASCL1

BHLH转录因子ASCL1(HASH1/MASH1)是确定 肺内的神经内分泌(NE)谱系。NE细胞在肺上皮中很少见，但它们 被认为在肺发育和动态平衡过程中扮演着不同的角色。NE信元增加 在儿童和成人的许多肺部疾病中都有记录表明这一数字。ASCL1函数为 与Notch信号平衡控制祖细胞增殖和NE分化与 肺中的其他细胞类型。与ASCL1作为谱系指定因子的作用一致 在不断扩大的祖细胞群体中，ASCL1被发现是一种血统依赖的 癌基因在肺NE肿瘤中也有表达。由于这些重要功能归因于ASCL1， 以及它在发育过程中对受控时空表达的要求 肺损伤的情况，令人惊讶的是，人们对ASCL1基因的调控知之甚少 抄写。这一知识差距反映了过去在识别和识别 操纵在距离目标基因很远的地方发现的顺式调控元件(RE)，在 除了反映东北人口和低比例人口的不良文化体系的挑战外 胚胎和成人肺中NE细胞的表达。遥控器远距离控制按键 人们正在利用先进的技术发现发育基因，这些技术可以询问 操纵空间基因组。在这里，我们将利用这些技术来获得更多 需要使用新报告的协议对ASCL1的转录控制有深入的了解 人IPSCs培养肺NE细胞及其细胞培养模型的研究 高表达ASCL1的神经内分泌癌。每种型号都有其独特的优势 这使得ASCL1监管的独特方面得以揭示。目标包括确定和 二者NE分化过程中调控ASCL1的远程RES的检测功能 模特们。这些目标的成功将提供功能性的非编码调控序列 控制ASCL1的表达，并推测，NE谱系在肺发育和 动态平衡。这对于未来的项目确定分子成分是很重要的 信号复合体通过这些RE工作，以达到提供理解的目标 定义转录调控因子的关键谱系在发育和发育过程中如何被控制 疾病。

The bHLH transcription factor ASCL1 (HASH1/MASH1) is essential for specification of the neuroendocrine (NE) lineage in the lung. NE cells are rare in pulmonary epithelium but they are thought to play diverse roles during lung development and homeostasis. Increases in NE cell number have been documented in many lung diseases in children and adults. ASCL1 function is balanced with NOTCH signaling to control progenitor proliferation and NE differentiation versus other cell types in the lung. Consistent with the role of ASCL1 as a lineage-specifying factor and in expanding progenitor populations, ASCL1 has been found to be a lineage-dependent oncogene in pulmonary NE tumors as well. With these important functions attributed to ASCL1, and its requirement for controlled spatial and temporal expression during development and in conditions of lung damage, it is surprising how little is known about regulation of ASCL1 gene transcription. This gap in knowledge reflects past technical challenges in identifying and manipulating cis-regulatory elements (REs) found at large distances from the gene of interest, in addition to challenges of poor culture systems reflecting this NE population and the low fraction of NE cells in embryonic and adult lungs. REs functioning at long-distances to control key developmental genes are being discovered using advances in technologies that can interrogate and manipulate the spatial genome. Here we will exploit these technologies to gain much needed insights into transcriptional control of ASCL1 using newly reported protocols for generating pulmonary NE cells from human iPSCs and leveraging cell culture models of neuroendocrine cancer that express high levels of ASCL1. Each model has a particular strength that allows unique aspects of ASCL1 regulation to be uncovered. Aims include identifying and testing functions of long-range REs controlling ASCL1 during NE differentiation in the two models. Success in these aims will provide functional non-coding regulatory sequences controlling ASCL1 expression, and presumably, the NE lineage in lung development and homeostasis. This is important for future projects to identify molecular components of the signaling complexes working through these REs to reach the goal of providing an understanding of how a key lineage defining transcriptional regulator is controlled during development and disease.