Signaling interactions underlying Fusion at the Primary palate

项目摘要/摘要 在胚胎发育的早期，三个面部隆起聚集在一起，融合成一个连续的上端 利普。这种多步骤手术经常失败，导致约1/700的新生儿发生唇裂。我们知道核聚变会失败 如果日冕不朝向彼此增长，但在日冕接触后也可能失效，如果 表面细胞不能接触到邻近日冕的表面细胞，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)是紧密联系在一起的 控制，因为我们只看到面部突起应该融合的这些行为(例如，形成 上嘴唇)，而不是其他地方(例如，舌头到口顶)。然而，我们对此一无所知 这些动态行为是受监管的。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 细胞的身份、允许它们相互通信的信号蛋白以及细胞骨架 控制其动态(或非动态)行为的元素。从这些数据中我们发现， 仅在融合区发现特殊数量的表面(基底上皮)细胞。这些细胞有一个 独特的信号签名，以及细胞骨架动力学的独特程序。我们假设他们的 信号特征开启相邻细胞的动态行为，启动并传播融合。作为一名 因此，我们预测，对这些信号的调制应该会调节融合的效率。为了检验这些想法 我们将开发同时可视化信号、细胞身份和动态行为(细胞 扩展)在融合过程中固定的整个鼠标面部。我们还将开发培养人脸的方法 融合，这样我们就可以实时研究母亲之外的过程。最后，我们将操作信号 在这些外植体中询问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 参与融合的细胞群体，指导它们独特行为的遗传程序，以及 协调和调节融合的信号相互作用。如果我们成功了，我们将识别信号 调节融合效率的途径，可以作为治疗靶点的途径 降低新生儿唇裂发生率的干预措施。

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.