Defining molecular pathways in monoamine circuit development using autism-related syndrome genes in zebrafish - ABSTRACT Autism Spectrum (AS) is a complex, heterogeneous condition associated with hundreds of genes. Modeling the genes that cause the changes in behavior is complex due to the need to study a large number of genes both in isolation and in combination. Syndromic conditions, like Pitt-Hopkins, Coffin-Siris, Rett, and Fragile X syndromes and others, are considered monogenic, with single causal genes linked to these syndromes. They also share features with AS, including social withdrawal, intellectual disability, sensory sensitivity, and anxiety. The involved genes act at a higher order of gene regulation, regulating several downstream processes, including additional genes and molecular pathways associated with AS. Defining which downstream molecular pathways cause changes in neural circuits and behavior could help prioritize which genes should be investigated in future research on autism-related genes. In this proposal, I propose to conduct behavioral assays, sequencing, and imaging of monoamine circuits and brain-wide changes in activity in zebrafish with mutations in genes associated with several syndromes in humans, namely the Pitt-Hopkins gene tcf4, the Coffin-Siris gene arid1b, bcl11ba, tcf7l2, ash1l, foxp1b, and hivep2a, all of which have namesake syndromes. All of these syndromes have symptoms seen in individuals with autism, including intellectual disability, seen in 1 in 3 individuals with autism. Several of these genes are also implicated in dopamine signaling, which is critical for social behaviors and processes like learning and memory. In the first aim, I will define changes in molecular pathways caused by these genes by performing bulk RNA sequencing, CUT&RUN, and Single-cell Combinatorial Indexing (sci) sequencing, and manipulating downstream direct targets of my focal genes. In aim 2, I will define effects on brain activity during a working memory task, define effects on pre- and post-synaptic structures, and define effects on circuit development. The work in this proposal will greatly enhance our understanding of common and distinct pathways altered by these syndrome-causing genes and potentially identify key pathways and circuits that should be emphasized in AS-related investigations. The findings will also set the stage for larger-scale studies, both in the broader field of modeling AS-related genes and that I can build my future lab around to investigate the molecular networks of transcription factors that underlie brain development.
