Signaling interactions underlying Fusion at the Primary palate

项目总结/摘要 在胚胎发育的早期，三个面部突起合并形成一个连续的鞋面 嘴唇这个多步骤的过程往往失败，导致唇裂的新生儿约1/700。我们知道核聚变会失败 如果双折射不朝向彼此生长，但如果双折射接触后， 表面细胞不能到达邻近突出的表面细胞，然后与之混合。 显然，表面细胞的这些动态行为（伸出，然后混合）是紧密相关的。 控制，因为我们只看到这些行为的面部一致性应该融合（例如，形成 上唇），而不是其他地方（例如舌头到口腔顶部）。但是我们不知道 这些动态行为受到调节。我们最近使用单细胞RNA测序来了解 参与融合的不同细胞的特征，包括给予融合的转录因子。 细胞的身份，信号蛋白，使他们能够相互沟通和细胞骨架 这些元素指导它们的动态（或不那么动态）行为。从这些数据中我们发现， 仅在融合区发现特殊的表面（基底上皮）细胞群。这些细胞具有 独特的信号特征，以及独特的细胞骨架动力学程序。我们假设他们的 信号特征开启相邻细胞的动态行为以启动并随后传播融合。作为 因此，我们预测调节这些信号应该调节融合的效率。为了验证这些想法 我们将开发同时可视化信号，细胞身份和动态行为（细胞）的方法， 延伸部）在融合期间固定整个小鼠面部。我们还将开发培养面部的方法， 这样我们就可以在母亲之外的真实的时间里研究这个过程。最后，我们将操纵信号 我们是否可以调节融合的效率。通过这种方式，我们希望定义 参与融合的细胞群，指导其独特行为的遗传程序， 协调和调节融合的信号相互作用。如果我们成功了， 调节融合效率的途径，可以开发为治疗靶点的途径， 干预措施，以减少新生儿唇裂的发病率。

Project Summary/Abstract Early in embryonic development three facial prominences come together and fuse to form a continuous upper lip. This multistep process often fails, leading to cleft lip in ~1/700 newborn infants. We know that fusion will fail if the prominences do not grow towards each other, but it can also fail after the prominences touch if the surface cells fail to reach out to and then intermingle with the surface cells of the neighboring prominence. Apparently these dynamic behaviors of surface cells (reaching out and then intermingling) are tightly controlled, because we only see these behaviors where facial prominences should be fusing (e.g. to form the upper lip) and not elsewhere (e.g. the tongue to the roof of the mouth). However we know nothing about how these dynamic behaviors are regulated. We have recently used single cell RNA sequencing to learn the characteristics of the different cells that participate in fusion, including the transcription factors that give the cells their identity, the signaling proteins that permit them to communicate with each other and the cytoskeleton elements that direct their dynamic (or not so dynamic) behaviors. From these data we have discovered that a special population of surface (basal epithelial) cells are found only at the fusion zone. These cells have a unique signaling signature, as well as a unique program for cytoskeletal dynamics. We hypothesize that their signaling signature turns on dynamic behaviors of adjacent cells to initiate and then propagate fusion. As a corollary, we predict that modulating these signals should modulate the efficiency of fusion. To test these ideas we will develop methods for simultaneously visualizing signaling, cell identity and dynamic behaviors (cellular extensions) in fixed whole mouse faces during fusion. We will also develop methods for culturing faces during fusion so that we can study the process in real time, outside of the mother. Finally, we will manipulate signaling in these explants to ask whether we can modulate the efficiency of fusion. In this way, we expect to define the cell populations that participate in fusion, the genetic programs that direct their unique behaviors and the signaling interactions that coordinate and regulate fusion. If we are successful, we will identify signaling pathways that regulate the efficiency of fusion, pathways that could be developed as targets for therapeutic interventions to reduce the incidence of cleft lip in newborn infants.