Transcriptional regulation of multiciliate cell differentiation

描述（由申请人提供）：在许多器官系统中，突出数百个跳动的纤毛的细胞，称为多纤毛细胞，产生强烈的流体流动，沿着腔体表面运输生物材料。多纤毛虫细胞分布在呼吸道、生殖道和脑室中，它们产生的流动对人类健康有重大影响。尽管它们很重要，但在不同上皮细胞中形成这些细胞的发育机制仍然未知。具体来说，多纤体细胞的分化很可能是在这种细胞类型形成所需的转录代码的控制下，但对这种代码的性质知之甚少。为了解决这个问题，拟议中的实验集中在一种新发现的基因上，称为Multicilin。在初步的实验中，我们根据其在X. laevis胚胎多纤体细胞中高度受限的表达，确定了Multicilin，但在形成多纤体细胞的其他器官中也有表达。在功能测试中，多纤毛虫细胞的形成需要多纤毛虫蛋白，更显著的是，当多纤毛虫细胞在胚胎的其他部位错误表达时，会诱导异位多纤毛虫细胞的形成。Multicilin编码一种小蛋白，其功能需要两个结构域：一个中心卷曲结构域，类似于细胞周期调节剂Geminin中发现的结构域，第二个c端结构域用于转录活性。因此，拟议的实验将确定Multicilin是否通过调节细胞周期进程和激活多纤毛虫细胞分化所需的基因表达来促进多纤毛虫细胞的形成。此外，为了诱导多纤毛细胞分化，Multicilin促进了锚定数百根纤毛所需的基底体的大规模组装。通过促进多纤毛虫细胞独特的中心粒组装的新途径，Multicilin可以被利用来深入了解这一鲜为人知的过程。因此，对Multicilin的分析结果将提供有关允许上皮祖细胞转变为多纤体细胞的转录和细胞生物学事件的新信息。这一信息可能会加速设计从干细胞（无论是诱导的还是胚胎的）中产生多纤毛虫细胞的方法，以及在再生过程中通过转分化促进其他细胞类型的多纤毛虫细胞的形成。

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.