Project Summary
Development of the nervous system requires the generation of diverse neuronal types that subsequently
drastically alter their shape and physiology to form vast interconnected networks. Each process requires
precise gene regulation. Technological innovations have drastically increased the scale at which we can
distinguish neuronal identities or stages based on transcriptomics or epigenetics. However, principles guiding
post-transcriptional control of gene expression, which is essential for neural development and homeostasis, by
regulatory factors including RNA-binding proteins (RBP) and miRNAs has not been defined at a similar
systematic level. As numerous neurodegenerative disorders have been linked to impaired RBP-RNA
interactions, and there is a huge need for improved cell type engineering strategies for therapeutics, insight
into this process is critically important. I propose to use the Drosophila visual system as a model to study post-
transcriptional regulation during specification and wiring of an entire neural sensory system. Specifically, this
proposal focuses on the regulation of mRNA translational repression, which is a conserved feature of both
neuronal fate diversification and differentiation in vertebrate and invertebrates. A single-cell transcriptomic atlas
of the developing visual system, or optic lobe, was recently described which defines the transcriptome of each
neuronal type in the optic lobe throughout development. Consistent with results from other model systems,
many genes associated with terminal neuronal function were detected at transcripts in the immature neurons
well before they are functionally required, and the corresponding protein was absent for two selected genes
studied. I aim to define the scope of translational regulation in this system by first performing whole-tissue and
select cell-specific ribosome profiling of the optic lobe over development, and determine the upstream control
of this process using a combination of bioinformatics and genetics (Aim 1). Next I will tease apart the molecular
and cellular mechanism by which two genes associated with different neuron signaling pathways are repressed
at the translational level to assess how their expression is coordinated (Aim 2). Finally, I will adapt a single-cell
translation profiling technique, scRibo-STAMP, in the Drosophila visual system to profile translation of all optic
lobe neurons during specification and wiring. Combined with machine-learning based analysis, I will predict
RBP/miRNA-RNA target interactions to gain fundamental insight into how RNA regulatory networks are shaped
(Aim 3). Together this study will provide significant insights into the role of translational regulation during
formation of the nervous system relevant to both human development and health.