JNK signaling coordinates with ecdysone signaling to promote dendrite pruning of Drosophila sensory neurons

Abstract

Developmental pruning of axons and dendrites is critical for the formation of precise neuronal connections, but the mechanisms underlying developmental pruning are not fully understood. Here we investigated the function of JNK signaling in dendrite pruning using Drosophila class IV dendritic arborization (c4da) neurons as a model. We found that loss of JNK or its canonical downstream effectors d-Jun or d-Fos led to dendrite pruning defects in c4da neurons. Interestingly, our data showed that JNK activity in c4da neurons remained constant from larval to pupal stages but the expression of d-Fos was specifically activated by ecdysone receptor B1 (EcRB1) at early pupal stages, suggesting that ecdysone signaling provides a temporal control for the regulation of dendrite pruning by JNK signaling. Thus, our work not only identified a novel pathway involved in dendrite pruning and a new downstream target of EcRB1 in c4da neurons, but also revealed that JNK and Ecdysone signaling coordinate to promote dendrite pruning.