retroLEAP: rAAV-based retrograde trans-synaptic labeling, expression and perturbation

Abstract Identifying and manipulating synaptically connected neurons across brain regions remains a core challenge in understanding complex nervous systems. RetroLEAP is a novel approach for retro grade trans-synaptic L abelling, E xpression A nd P erturbation. GFP-dependent recombinase (Flp-DOG) detects trans-synaptic transfer of GFP-tetanus toxin heavy chain fusion protein (GFP-TTC) and activates expression of any gene of interest in synaptically connected cells. RetroLEAP overcomes existing limitations, is non-toxic, highly flexible, efficient, sensitive and easy to implement.