During animal development, neurons selectively remove superfluous synaptic connections, strengthen key synapses, and optimize neural circuits in the brain, which is a core mechanism for fine-tuning the development of the nervous system. Drosophila class IV dendritic arborization (C4da) sensory neurons undergo dendrite-specific pruning during development. Nevertheless, the cell-autonomous inhibitory mechanisms of dendritic pruning in C4da neurons are largely unknown. Here, we discovered Ribbon (Rib), a nuclear BTB-domain protein, whose malfunction in C4da neurons causes a precocious occurrence of dendritic pruning. Our study further shows that the regulation of dendritic pruning by Rib is dependent on Akt/Tor signaling. Moreover, actin polymerization factors and exocyst complex subunits are also involved in repressing dendritic pruning and function as downstream effectors of Rib and Akt/Tor signaling. Overall, the present study reveals a cell-autonomous inhibitory mechanism of Rib in dendritic pruning, with a perspective to provide new insights into neurodevelopment and the pathogenesis of relevant neurological disorders.
Wang et al. (Thu,) studied this question.