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. 2018 Feb 1;145(3):dev158246. doi: 10.1242/dev.158246

Fig. 5.

Fig. 5.

Sdk is localized to the dendrites of T4 and T5, but is not required for them to receive synaptic input. (A-D) Brains labeled with anti-Chp to mark photoreceptor axons (magenta) and anti-Sdk (green). (A) 24 h APF, (B) 42 h APF, (C) 55 h APF and (D) 72 h APF. Lower panels show enlargements of the distal medulla, with dotted lines marking the terminals of R7 and R8. During pupal stages, Sdk is localized to the lamina (La, arrow), to synaptic layers M3a and M10 in the medulla (M), and to Lo1 in the lobula (Lo), but is absent from the R7 and R8 growth cones. Arrowhead in A indicates glial cell bodies. (E) Diagram showing the projection patterns of identified Sdk-expressing neurons in the motion-detection pathways. (F) Adult brain showing subsets of neurons that express NP3507-GAL4, labeled with Citrine using the Flybow system. T4, T5 and C2 cell bodies (arrows) and neurites (arrowheads) are indicated. (G,G′) 55 h APF brain in which sdk RNAi is expressed in T4 and T5 with GMR42F06-GAL4, labeled with anti-Chp (magenta) and anti-Sdk (G′, green). Sdk is lost from the cell bodies in the lobula plate cortex (asterisk, compare with asterisk in C) and from the M10 and Lo1 layers, which contain the dendrites of T4 and T5, respectively. (H-I,K-L′) Adult brains, with the Lo1 layer (arrow in H) enlarged in H′,I,K-L′. (H-I) Endogenous Brp is tagged with V5 in Tm9 to label concentrations of presynaptic active zones (H′,I, green in H). Myr-tdTomato (magenta) labels the Tm9 neurons. (H,H′) sdkΔ7; (I) sdkMB05054. Brp-V5 puncta/µm2 in the Lo1 layer, counted in J (mean±s.e.m.), show no significant difference (P>0.5, t-test) between sdkΔ7 controls and mutants. n=94 sections from eight optic lobes (sdkΔ7), 110 sections from 10 optic lobes (sdkMB05054). (K-L′) GFP reconstituted from presynaptic Syb-GFP1-10 expressed in Tm9 and postsynaptic CD4-GFP11 expressed in T5 (K′,L′, green in K,L). Tm9 terminals are labeled with myr-tdTomato (magenta). (K,K′) sdkΔ7; (L,L′) sdkMB05054. The GRASP signal is taken to indicate that functional synapses are formed between Tm9 and T5 in sdk mutants. Scale bars: 20 µm.