Transcriptional regulation of multiciliate cell differentiation

描述(申请人提供)：在许多器官系统中，投射出数百个跳动的纤毛的细胞，称为多纤毛细胞，产生强劲的液体流动，沿着管腔表面运输生物材料。多纤毛细胞存在于呼吸道和生殖道以及脑室，它们产生的流量对人类健康具有重大影响。尽管它们很重要，但在不同的上皮细胞中形成这些细胞的发育机制仍然未知。具体地说，多纤毛细胞的分化很可能受转录密码的控制，而转录密码是形成这种细胞类型所必需的，但人们对这种密码的性质知之甚少。为了解决这个问题，拟议中的实验重点放在一种新发现的基因上，称为Multiclin。在初步实验中，基于其在多纤毛细胞中的高度限制性表达而被鉴定，但在形成多纤毛细胞的其他器官中也有表达。在功能测试中，Multicin是形成多纤毛细胞所必需的，更显著的是，当在胚胎的其他区域错误表达时，会诱导异位多纤毛细胞的形成。Multiclin编码一个小蛋白，具有两个功能所需的结构域：一个中心卷曲结构域，类似于细胞周期调节因子中发现的结构域，以及第二个转录活动所需的C末端结构域。因此，拟议的实验将确定Multiclin是否通过调节细胞周期进程和激活多纤毛细胞分化所需的基因表达来促进多纤毛细胞的形成。此外，为了诱导多纤毛细胞分化，Multiclin促进锚定数百个纤毛所需的基底的大规模组装。通过促进多纤毛细胞特有的中心粒组装的新途径，可以利用Multiclin来深入了解这一鲜为人知的过程。因此，对Multiclin的分析结果将提供有关转录和细胞生物学事件的新信息，这些事件允许上皮祖细胞转变为多纤毛细胞。这些信息可能会加快从诱导干细胞或胚胎干细胞产生多纤毛细胞的方法的设计进展，以及通过转分化促进来自其他细胞类型的再生过程中多纤毛细胞的形成。 公共卫生相关性：多纤毛细胞通过在脑、肺和生殖道中产生液体流动，在人类健康中发挥重要作用，但在胚胎发育过程中调节这些细胞形成的机制尚不清楚。为了研究这些机制，拟议的研究将集中在一种名为Multiclin的新基因上，这种基因对于促进多纤毛细胞的形成既是必要的，也是充分的。分析Multiclin的功能将有助于诊断和治疗影响纤毛上皮细胞的人类疾病，如原发纤毛运动障碍和Kartegener综合征时出现的纤毛缺陷。

DESCRIPTION (provided by applicant): In many organ systems, cells projecting hundreds of beating cilia, called multiciliate cells, produce a vigorous fluid flow that transports biological materials along luminal surfaces. Multiciliate cells populate the respiratory and reproductive tracts, and the ventricles of the brain, and the flow they produce has significant implications for human health. Despite their importance, the developmental mechanisms that underlie the formation of these cells in diverse epithelia are still unknown. Specifically, multiciliate cell differentiation is likely to be under the control of a transcriptional code that is required for this cell type to form, but little is known about the nature of this code. To address this issue, the proposed experiments focus on a newly discovered gene, called Multicilin. Multicilin was identified in preliminary experiments based on its highly restricted expression in multiciliate cells in X. laevis embryos, but is also expressed in other organs that form multiciliate cells. In functional tests, Multicilin is required for multiciliate cells to form, and more remarkably will induce the formation of ectopic multiciliate cells when misexpressed in other regions of the embryo. Multicilin encodes a small protein with two domains required for function: a central coiled-coil domain similar to the one found in the cell cycle regulator, Geminin, and a second C-terminal domain required for transcriptional activity. Thus, the proposed experiments will determine whether Multicilin promotes the formation of multiciliate cells by both modulating cell cycle progression and by activating gene expression required for multiciliate cell differentiation. In addition, in order to induce multiciliate cell differentiation, Multicilin promotes the large-scale assembly of basal bodies required to anchor hundreds of cilia. By promoting novel pathways of centriole assembly that are unique to multiciliate cells, Multicilin can be exploited to gain insight into this poorly understood process. Thus, the results from the analysis of Multicilin will provide new information about the transcriptional and cell biological events that allow epithelial progenitors to turn into multiciliate cells. This information will likely speed progress in devising approaches to generate multiciliate cells from stem cells, either induced or embryonic, and for promoting the formation of multiciliate cells from other cell types during regeneration via transdifferentiation. PUBLIC HEALTH RELEVANCE: Multiciliate cells play important roles in human health by generating fluid flow in the brain, lung and reproductive tract, but the mechanisms that mediate the formation of these cells during embryogenesis are poorly understood. To study these mechanisms, the proposed research will focus on a new gene, called Multicilin, which is both necessary and sufficient to promote multiciliate cell formation. Analyzing Multicilin function will aid in the diagnosis and treatment of human disease that affect ciliated epithelia, such as the ciliary defects that occurs during primary ciliary dyskinesia and Kartegener's syndrome.