Photoreceptor-derived activin promotes dendritic termination and restricts the receptive fields of first-order interneurons in Drosophila.

摘要: How neurons form appropriately sized dendritic fields to encounter their presynaptic partners is poorly understood. The Drosophila medulla organized in layers and columns innervated by neuron dendrites photoreceptor axons. Here, we show that three types of projection (Tm) extend stereotyped directions distinct within a single column for processing retinotopic information. In contrast, the Dm8 amacrine wide field receive ∼16 R7 inputs. R7- R8-derived Activin selectively restricts respective postsynaptic partners, Tm20, size appropriate functions. Canonical signaling promotes termination without affecting routing direction or layer. Tm20 lacking expanded aberrantly synapsed with neighboring photoreceptors. We suggest afferent-derived regulates ensure synaptic partnership.