Human genetic and genomic studies have supported a strong causal role ofSHANK3deficiency in autism spectrum disorder (ASD). However, the molecular mechanism underlyingSHANK3deficiency resulting in ASD is not fully understood. Recently, the zebrafish has become an attractive organism to model ASD because of its high efficiency of genetic manipulation and robust behavioral phenotypes. The orthologous gene to humanSHANK3is duplicated in the zebrafish genome and has two homologs,shank3aandshank3b. Previous studies have reportedshank3morphants in zebrafish using the morpholino method. Here, we report the generation and characterization ofshank3bmutant zebrafish in larval and adult stages using the CRISPR/Cas9 genome editing technique.
CRISPR/Cas9 was applied to generate ashank3bloss-of-function mutation (shank3b
-/-
) in zebrafish. A series of morphological measurements, behavioral tests, and molecular analyses were performed to systematically characterize the behavioral and molecular changes inshank3bmutant zebrafish.
shank3b
-/-
zebrafish exhibited abnormal morphology in early development. They showed reduced locomotor activity both as larvae and adults, reduced social interaction and time spent near conspecifics, and significant repetitive swimming behaviors. Additionally, the levels of both postsynaptic homer1 and presynaptic synaptophysin were significantly reduced in the adult brain ofshank3b-deficient zebrafish.
We generated the first inheritableshank3bmutant zebrafish model using CRISPR/Cas9 gene editing approach.shank3b-/-zebrafish displayed robust autism-like behaviors and altered levels of the synaptic proteins homer1 and synaptophysin. The versatility of zebrafish as a model for studying neurodevelopment and conducting drug screening will likely have a significant contribution to future studies of humanSHANK3function and ASD.