Regulating transcription of the key pulmonary neuroendocrine lineage driver ASCL1

bHLH转录因子ASCL 1（HASH 1/MASH 1）是细胞内特异性表达的重要因子。 神经内分泌（NE）谱系。NE细胞在肺上皮细胞中很少见，但它们是 被认为在肺发育和体内平衡过程中发挥着不同的作用。NE细胞增加 在儿童和成人的许多肺部疾病中，ASCL 1功能 与NOTCH信号传导平衡以控制祖细胞增殖和NE分化， 其他类型的细胞。与ASCL 1作为谱系特异性因子的作用一致， 在不断扩大的祖细胞群体中，发现ASCL 1是一种谱系依赖性基因， 癌基因在肺NE肿瘤中的表达。由于ASCL 1具有这些重要功能， 以及在发育过程中和发育过程中对控制空间和时间表达的要求， 在肺损伤的情况下，令人惊讶的是，人们对ASCL 1基因的调控知之甚少。 转录。这一知识差距反映了过去在确定和 操纵在距离感兴趣的基因很远的地方发现的顺式调节元件（RE）， 除了反映这一东北人口和低比例的贫困文化系统的挑战外， NE细胞在胚胎和成人肺中的分布。远程遥控器 利用先进的技术发现了发育基因， 并操纵空间基因组。在这里，我们将利用这些技术， 需要深入了解转录控制ASCL 1使用新报告的协议， 从人iPSC产生肺NE细胞，并利用 表达高水平ASCL 1的神经内分泌癌。每种型号都有其独特的优势 这使得ASCL 1调控的独特方面得以揭示。目标包括确定和 在两个人的NE分化过程中测试控制ASCL 1的远程RE的功能， 模型这些目标的成功将提供功能性非编码调控序列 控制ASCL 1的表达，并可能控制肺发育中的NE谱系， 体内平衡这对未来的项目，以确定分子组成的 信号复合物通过这些RE工作，以达到提供理解的目标， 一个关键的谱系定义转录调节因子是如何在发育过程中被控制的， 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.