Fig. 2: Schematic of ATLAS transsynaptic transport and testing in vitro.
From: ATLAS: a rationally designed anterograde transsynaptic tracer
a, ATLASCre protein (VAMP2-At-BACEcs-AF-Cre) is expressed in a presynaptic starter cell and (1) targeted to synaptic vesicles by a VAMP2 domain. (2) A BACE cleavage site within the ATLAS protein is cleaved before release. (3) A peptide domain consisting of AF fused to Cre is released into the synaptic cleft and (4) subsequently binds to the extracellular domain of postsynaptic GluA1. (5) It is internalized through endocytosis and transported to the endosome. (6) AF-Cre moves to the nucleus, where Cre can catalyze the expression of a floxed reporter gene. b, Cortical neuron in culture expressing ATLASCre protein (arrow) following transfection, stained with anti-ALFA-tag (At) nanobody. Four other neurons shown (arrowheads) do not express At. c, Cre staining of the same neurons as in b including a neuron expressing ATLASCre (arrow), and four not expressing ATLASCre (arrowheads). d, GFP labeling of postsynaptic cells (arrowheads, green) following infection of AAV8-DIO-GFP. e, Combined labeling of At, GFP and Cre showing presynaptic (arrow) and postsynaptic neurons (arrowheads). Scale bars, 100 μm.
