The synaptic connectivity of the sLNvs with clock and non-clock cells undergoes circadian structural remodeling

DEPETRIS-CHAUVIN, A.; GOROSTIZA, E.A.; PÍREZ, N.; FRENKEL, L.; CERIANI, M.F.

Big Sky

Conferencia; Society for Research on Biological Rhythms Meeting; 2014

Society for Research on Biological Rhythms

Our lab has previously reported that sLNvs neurons, the central pacemaker in Drosophila, undergo circadian remodeling of their dorsal axonal projections, and we have put forward the hypothesis that this structural plasticity provides the substrate for the circadian control of activity and connectivity of the PDF circuit. Here we show that this remodeling implies daily changes in presynaptic markers of active zones, opening the possibility that the connectivity is indeed changing daily. To map this connectivity, we employed a membrane-tethered splitGFP strategy, which revealed that PDF axons contact different synaptic partners along the day, extending the impact of core pacemaker neurons to circuits outside of the circadian network. Within circadian clusters, a restricted subset of lateral dorsal neurons contact the sLNv axonal termini in a time-of-day-dependent manner. To test the hypothesis that the circadian structural remodeling is capable of affecting the synaptic output of PDF neurons we are currently performing live whole brain optical imaging experiments to corroborate if the synaptic partners identified through GRASP are indeed functional. Combining two binary expression systems (e.g. GAL4/UAS and lexA/lexAop) we will specifically activate PDF neurons and monitor the putative post synaptic partners by means of a protein-encoded reporter of neuronal activity. This strategy will enable us to map the connectivity of the circadian network.