SRP485931 PRJNA1069039 GSE254224 Mice lacking Astn2 have ASD-like behaviors and altered cerebellar circuit properties Astrotactin 2 (ASTN2) is a transmembrane, neuronal protein that functions in receptor trafficking and modulates cerebellar Purkinje cell (PC) synaptic activity. We recently reported a family with a paternally inherited intragenic ASTN2 duplication, with a range of neurodevelopmental disorders, including autism spectrum disorder (ASD), learning difficulties and speech and language delay. To provide a genetic model for the role of the cerebellum in ASD-related behaviors and study ASTN2 role in cerebellar circuit function, we generated global and Purkinje cell-specific conditional Astn2 knockout (KO and cKO, respectively) mouse lines. Astn2 KO mice exhibit strong ASD-related behavioral phenotypes, including a marked decrease in separation-induced pup ultrasonic vocalization (USV) calls, increased hyperactivity and repetitive behaviors, altered social behaviors, and impaired cerebellar-dependent eyeblink conditioning. Increased hyperactivity and repetitive behaviors were also prominent in Astn2 cKO animals. By Golgi staining, Astn2 KO PCs have region-specific changes in dendritic spine density and filopodia numbers. Proteomic analysis of Astn2 KO cerebellum reveals a marked upregulation of ASTN2 family member, ASTN1, a neuron-glial adhesion protein. Immunohistochemistry and electron microscopy demonstrates a large increase in Bergmann glia volume in the molecular layer of Astn2 KO animals. Electrophysiological experiments indicate a reduced frequency of spontaneous EPSCs, as well as increased amplitudes of both spontaneous EPSCs and IPSCs in the Astn2 KO animals, suggesting that pre- and post-synaptic components of synaptic transmission are altered. Thus, ASTN2 regulates ASD-like behaviors and cerebellar circuit properties. Overall design: We crossed Astn2 WT and KO mice with Tg(Pcp2-L10a-EGFP) bacTRAP line to analyze Purkinje cell-specific gene expression changes in mice lacking ASTN2. Cerebella from WT and KO littermates were isolated at P21 and translating mRNA was isolated using the TRAP methodology. GSE254224 pubmed 38405978 pubmed 39150780