UCLA

During circuit assembly in the developing brain, neurons undergo dynamic expression of many neurotransmitter receptor (NR) subunits that are used to establish a series of postsynaptic domains. However, our understanding of the molecular logic that determines synapse composition between classes of inputs remains limited. The Drosophila central nervous system demonstrates particularly striking specificity of synapse types. Here, I report the use of new tools developed to study the localization of endogenously expressed NR subunits in sparsely distributed cells, thus offering a window into the process of synaptogenesis and the establishment of variously defined postsynaptic sites in the brain. I use a combination of genetic methods and expansion microscopy (ExM) to investigate NR localization in the fly brain at the scale of single synapses. In developmental studies, I also present evidence of temporally distinct dynamics of synapse formation that differ between NR type as well as cell type. Lastly, I explore methods to uncover mechanisms that regulate NR localization in these cells. This work describes newly advanced methods that can be leveraged to probe the molecular architecture of synapses in vivo and suggests a complex picture of how synapse formation is coordinated through differential, synapse-specific processes during development.