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My project uses zebrafish to test how loss of function mutations in Synaptic Ras-GTPase Activating Protein 1 (SYNGAP1) impact neural circuit function. SYNGAP1 is a component of the postsynaptic density of glutamatergic synapses and plays an essential role in receptor trafficking and synaptic strengthening allied with learning and memory. In our lab, we have generated stable syngap1ab mutant zebrafish models of ASD using CRISPR/Cas 9 genome editing. Using these models, we are quantifying ASD-relevant behaviors with the ultimate goal of delineating the neural-circuit-level mechanisms underlying those behaviors. Due to sensory-induced hyperactivity observed in humans with heterozygous SYNGAP1 loss-of-function variants, we tested syngap1ab+/-zebrafish mutants to see whether they would be similarly hyperactive in response to light and/or sound (tap) stimuli. We found that the syngap1ab+/- mutants do exhibit hyperactivity in response to both light and tap stimuli at six days post-fertilization. Our kinematic data from syngap1ab +/- larvae show a significant increase in swim velocities when tapped, and increased duration of swim bouts compared to WT larvae with no alterations associated with swim coordination. Taken together, these results suggest that possible involvement of Syngap1 in the early development of sensory-motor integration in the zebrafish.

Figure S1. Insertion mutations in zebrafish shank3 orthologues produce unique restriction maps for genotyping. Figure S2. a Transverse 5 μm section of adult WT upper intestinal tissue stained with alcian blue and Eosin B (n = 6 for WT, n = 6 for shank3abΔC +/− and n = 6 for shank3abΔC −/−). b 40x magnification shows dense plicae that extend to the point of nearly occluding the luminal space. c, d In shank3abΔC +/− upper intestinal tissue, increased counts of goblet cells (black arrowheads) suggest inflammation. e, f Homozygous shank3abΔC −/− adults also show increased goblet cell count. Table S1. Oligonucleotides used for sgRNA synthesis. Table S2. Primers used for PCR and sanger sequencing. Table S3. % bead occupancy in WT and shank3abΔC+/− larvae at 3 h post-feed. Table S4. % bead occupancy in WT and shank3abΔC+/− larvae at 6 h post-feed. Table S5. % bead occupancy in WT and shank3abΔC+/− larvae at 12 h post-feed. Table S6. % bead occupancy in WT and shank3abΔC+/− larvae at 24 h post-feed. Table S7. Upper and lower GI rate of peristaltic period (seconds between contractions). Table S8. R script for Permutation. Table S9. shank3abΔC+/− injected with either Human SHANK3 mRNA short (32T) or long (5 T) isoform, 3–24 h post feed. (DOCX 4255 kb)