Institute of Neuroscience, University of Oregon, Eugene, USA.
J Comp Neurol. 2021 Jun;529(9):2176-2188. doi: 10.1002/cne.25084. Epub 2020 Dec 17.
As they form, synapses go through various stages of maturation and refinement. These steps are linked to significant changes in synaptic function, potentially resulting in emergence and maturation of behavioral outputs. Synaptotagmins are calcium-sensing proteins of the synaptic vesicle exocytosis machinery, and changes in Synaptotagmin proteins at synapses have significant effects on vesicle release and synaptic function. Here, we examined the distribution of the synaptic vesicle protein Synaptotagmin 2a (Syt2a) during development of the zebrafish nervous system. Syt2a is widely distributed throughout the midbrain and hindbrain early during larval development but very weakly expressed in the forebrain. Later in development, Syt2a expression levels in the forebrain increase, particularly in regions associated with social behavior, and most intriguingly, around the time social behavior becomes apparent. We provide evidence that Syt2a localizes to synapses onto neurons implicated in social behavior in the ventral forebrain and show that Syt2a is colocalized with tyrosine hydroxylase, a biosynthetic enzyme in the dopamine pathway. Our results suggest a developmentally important role for Syt2a in maturing synapses in the forebrain, coinciding with the emergence of social behavior.
在形成过程中，突触经历了多个成熟和细化阶段。这些步骤与突触功能的重大变化有关，可能导致行为输出的出现和成熟。突触结合蛋白是突触小泡胞吐机制中的钙感应蛋白，突触中突触结合蛋白的变化对囊泡释放和突触功能有显著影响。在这里，我们研究了突触小泡蛋白突触结合蛋白 2a（Syt2a）在斑马鱼神经系统发育过程中的分布。Syt2a 在幼虫发育早期广泛分布于中脑和后脑，但在前脑中表达较弱。在发育后期，前脑中 Syt2a 的表达水平增加，特别是在与社会行为相关的区域，最引人注目的是，在社会行为变得明显的时候。我们提供的证据表明，Syt2a 定位于腹侧前脑与社会行为相关的神经元上的突触，并表明 Syt2a 与酪氨酸羟化酶共定位，酪氨酸羟化酶是多巴胺途径中的一种生物合成酶。我们的研究结果表明，Syt2a 在成熟前脑突触中具有重要的发育作用，与社会行为的出现相吻合。
