ftz-f1 and Hr39 opposing roles on EcR expression during Drosophila mushroom body neuron remodeling

Ana Boulanger (1) , Jean-Maurice Dura (1)

1 Genetics and Development

Developmental axon pruning is a general mechanism required for maturation of neural circuits. During Drosophila metamorphosis, the larval-specific dendrites and axons of early γ neurons of the mushroom bodies are pruned and replaced by adult-specific processes. We show here that the nuclear receptor ftz-f1 is required for this pruning and has two roles: (i) to activate expression of the steroid hormone receptor EcR-B1 whose activity is essential for γ remodeling and (ii) to repress expression of Hr39, a ftz-f1 homologous gene. If inappropriately expressed in the γ neurons, HR39 inhibits normal pruning likely by competing with endogenous FTZ-F1 that results in decreased EcR-B1 expression. EcR-B1 was previously identified as a target of the TGF-β signaling pathway. Here we show that the ftz-f1/Hr39 pathway acts apparently independent from TGF-β signaling, suggesting that EcR-B1 is the target of two parallel molecular pathways acting during γ neuron remodeling.

Mots clés: Development; genetics

Ana Boulanger, Jean-Maurice Dura. ftz-f1 and Hr39 opposing roles on EcR expression during Drosophila mushroom body neuron remodeling. Nature Neuroscience, 2010, ⟨10.1038/nn.2700⟩. ⟨hal-00598184⟩