Effect of Apelin receptor signaling on Nodal activity during mesendoderm development

动物发育的基本过程是单个细胞（受精卵）神奇地转变为组成我们身体的大量不同类型的细胞。这个过程的第一步是干细胞的产生，干细胞将在以后制造出动物的所有细胞类型。在胚胎中，这一过程发生在原肠胚形成期间，此时有协调的细胞运动和细胞间的交流，产生我们的身体轴，并使制造动物所需的干细胞群多样化。在我的研究中，我们使用斑马鱼胚胎来研究这一过程，这是一个研究早期发育过程的绝佳模型。胚胎放置在水中，发育迅速，并且光学清晰，使我们能够观察到在原肠胚形成和干细胞生成过程中发生的所有细胞运动和分子事件。由于我们可以对这些生物进行基因改造，我们可以很容易地确定基因如何调节动物发育中的这一关键里程碑。

The fundamental process in animal development is the miraculous transition of a single cell (the fertilized egg) into the large numbers of diverse cell types that make up our bodies. One of the first steps in this process is the generation of the stem cells that will later make all the cell types of the animal. In the embryo, this process occurs during gastrulation, when there are coordinated cell movements and cell-to-cell communication that generate our body axis and diversify the stem cell populations needed to make the animal. For my research, we study this process using the zebrafish embryo, a fantastic model to examine how early development occurs. Embryos are laid in water, develop rapidly, and are optically clear, allowing us to watch all the cell movements and molecular events that happen during gastrulation and stem cell generation. As we can genetically modify these organisms, we can easily determine how genes regulate this key milestone in animal development. My lab has found that a cell surface receptor, called the Apelin Receptor (Aplnr), influences development at this key stage. In the absence of the Aplnr function, there is a deficit in formation of the precursors of the heart and digestive organs. Our work has shown that Aplnr acts during gastrulation to boost the activity of the Nodal signaling pathway. This is of great interest, as the levels of Nodal signal a cell receives are known to control what path that cell will follow (heart cell, gut cell, neuron, etc.). Aplnr therefore acts as a dial that fine-tunes how much Nodal signal is active at a key stage in development. This gives us a unique opportunity to study how cells decide to become both the right type and right amount of stem cells to allow animal development to occur. We now need to understand how the Aplnr influences Nodal signaling. In this research, we will use the zebrafish embryo to determine how Aplnr activity affects early development and production of the various cell types needed in an animal body. Ultimately, this research will provide fundamental information on how the diversity of cell types found in our bodies is generated. Further, our work will help scientists generate specific cell types required for their research, allowing precise modeling of physiology and development.