Extended Data Fig. 3: Synapse formation in the visual system depends on PSINA.
From: A discrete neuronal population coordinates brain-wide developmental activity
a. Table comparing control synapse counts in cells with sparse synaptic density across EM and light microscopy studies. Values are mean synapse count ± SD, with sample size in parentheses. b–g. Left: representative micrographs of R8 (B), L1 (C), L4 (D), L5 (E), Dm9 (F), and Tm9 (G) neurons in control (left set) and trpγ (right set) animals with cell membranes (myr::tdTOM, magenta in merged) and presynaptic sites (BRP-V5, cyan in merged) labeled. Right: Brp puncta counts by layer in heterozygous control (black, n=18-61 per cell type) and trpγ (orange, n=26-65 per cell type) animals. Points indicate individual cells. Box-and-whiskers mark 5th, 25th, 50th, 75th, and 95th percentiles. *, p<0.05; **, p<0.01; ***, p<0.001 by Welch’s t-test following Shapiro-Wilk test. h. Brp puncta counts in Trpγ heterozygotes (black, n=18 for Dm9, n=30 for Tm9), trpγ nulls (orange, n=24 for Dm9, n=30 for Tm9), or trpγ nulls with Trpγ-D expressed in Trpγ+ cells (cyan, n=24 for Dm9, n=30 for Tm9). Boxplots as in B-G. *, p<0.05; **, p<0.01; ***, p<0.001 by Tukey’s post-hoc test following ANOVA for multiple groups. i. Brp puncta counts in control (black, n = 24) or trpγ null (orange, n = 30) L5 clones generated by MARCM. Boxplots as in B-G. *, p<0.05; **, p<0.01; ***, p<0.001 by Welch’s t-test following Shapiro-Wilk test. j. Average Brp puncta through development in control (black, n=64-88 per timepoint) or animals with PSINA blocked with pan-neuronally expressed TNT (magenta, n=35-68 per timepoint). Presynaptic sites assessed at 60, 72, and 84 hAPF. Error bars, SD.
