Fig. 2.

Super-resolution imaging of tripartite synapses in fixed mouse brain sections. (A) Wide-field images of astrocytic glutamate transporter GLT-1 (A1) and presynaptic protein bassoon (A2) and postsynaptic protein Homer1 (A3) in hippocampal CA1 area stratum radiatum in a fixed mouse 30 μm brain section (P160 male C57BL/6J). (B) 3D three-color dSTORM super-resolution imaging: Snapshots of molecular patterns for astrocytic GLT-1 (Alexa 647, B1), presynaptic bassoon (CF568, B2) and postsynaptic Homer1 (Atto 488, B3). The images are colour-coded according to the z position of the molecules in a 2 μm deep stack. (C) Merged image of images shown in B; GLT-1 (blue), bassoon (magenta) and Homer1 (green). Displayed are 2D projections of 3D SMLM molecular maps; label brightness reflects molecular density. (D) Close-up on the highlighted area in C; two viewing angles shown. (E) Same images as in B but as cloud representations of localised molecules with a constant diameter of 30 nm. (F) Merged image of images shown in E. (G) Close-up on the highlighted area in F; two viewing angles shown. (H) Nearest-neighbour distances (<500 nm) between synaptic molecules bassoon and Homer1 (H1). Distances of GLT-1 molecules to the center of identified synapses, bassoon or Homer1 molecules (H2). A zoomed in view of the distances up to 200 nm highlights that more GLT-1 molecules are closer to Homer1 than to bassoon or to the synapse center (H3). Scale bars = 5 μm (A-C and E-F) and 1 μm (D and G). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)