Maturation of a central brain flight circuit in Drosophila requires Fz2/Ca2+ signaling

Abstract

The final identity of a differentiated neuron is determined by multiple signaling events, including activity dependent calcium transients. Non- canonical Frizzled2 (Fz2) signaling generates calcium transients that determine neuronal polarity, neuronal migration and synapse assembly in the developing vertebrate brain. Here, we demonstrate a requirement for Fz2/Ca2+ signaling in determining the final differentiated state of a set of central brain dopaminergic neurons in Drosophila, referred to as the PAM cluster. Knockdown or inhibition of Fz2/Ca2+ signaling during maturation of the flight circuit in pupae reduces Tyrosine Hydroxylase (TH) expression in the PAM neurons and affects maintenance of flight. Thus we demonstrate that Fz2/Ca2+ transients during development serve as a pre-requisite for normal adult behavior. Our results support a neural mechanism where PAM neuron send projections to the α’ and β’ lobes of a higher brain centre, the mushroom body, and function in dopaminergic re-inforcement of flight.