In Vivo Analysis of the Developing Vertebrate Retina

描述（由申请人提供）：神经系统中的突触连接是高度特异性的。在中枢神经系统的某些区域，突触特异性源于更分散的早期连接模式的重组，而在其他区域，精确的模式可能从一开始就存在。因此，神经生物学中最具挑战性和最重要的问题之一是如何在发育过程中精确地建立神经元回路。我们感兴趣的是了解神经回路是如何在脊椎动物视网膜中形成和组织的，特别是潜在的突触前和突触后细胞之间的相互作用如何在发育过程中指导这一过程。尽管从体外工作中获得了很多知识，但很明显，在体内检查这一过程将提供对建立突触特异性所发生的动态相互作用的深入了解。斑马鱼是研究视网膜回路在体内发育的理想模型。这是因为突触形成在受精后的几天内完成，斑马鱼胚胎可以保持透明，适合在突触形成和成熟的整个过程中进行体内成像。在这个应用中，我们建议将重点放在视网膜内网络的发展上。我们将确定视网膜神经节细胞的突触后树突和无突细胞的突触前末梢是如何生长和细化的，它们共同形成第一个视网膜网络，在发育过程中接触并形成突触区域，即内丛状层（IPL）。我们将结合延时体内成像技术和分子方法来阐明IPL发育的正常模式，然后将这些技术与视网膜突变体一起应用，以确定细胞间相互作用在组织该突触层中的作用。总之，这些研究的结果将进一步加深我们对视网膜内回路结构和功能发展机制的理解。

DESCRIPTION (provided by applicant): Synaptic connections in the nervous system are highly specific. In some regions of the central nervous system, synapse specificity arises from the reorganization of more diffuse, early patterns of connectivity whereas in other regions, precise patterns may be present from the very beginning. Thus, one of the most challenging and important issues in neurobiology concerns how neuronal circuits are established with precision during development. We are interested in understanding how neural circuits are formed and organized in the vertebrate retina, and in particular how interactions between potential pre- and postsynaptic cells guide this process during development. Although much knowledge has been gained from in vitro work, it is evident that examining this process in vivo will provide insight into the dynamic interactions that take place to establish synaptic specificity. The zebrafish is an ideal model for studying the in vivo development of retinal circuits. This is because synapse formation is completed within a few days after fertilization and the zebrafish embryo can be maintained transparent, making it suitable for in vivo imaging throughout the period of synapse formation and maturation. In this application, we propose to focus on the development of networks in the inner retina. We will determine how outgrowth and elaboration of the postsynaptic dendrites of retinal ganglion cells and the presynaptic terminals of amacrine cells, that together form the first retinal network, contact and form the synaptic region, the inner plexiform layer (IPL) during development. We will combine time-lapse in vivo imaging techniques with molecular approaches to elucidate the normal pattern of IPL development, and then apply these techniques together with the use of retinal mutants to ascertain the role of cell-cell interactions in organizing this synaptic layer. Together, the results of the proposed studies will further our understanding of the mechanisms underlying the structural and functional development of the inner retinal circuitry.