Project Summary/Abstract The contribution of individual disease-relevant genes to brain development still remains unknown. The long-term goal of our laboratory is to elucidate the intersection of molecular signaling pathways that are disrupted in neurodevelopmental disorders with those pathways that are important for specific aspects of brain development. Two members of the FOXP family of transcription factors, FOXP1 and FOXP2, have been linked to monogenetic forms of intellectual disability, autism spectrum disorders, and specific speech and language deficits. Variants in FOXP1 or FOXP2 are among the most significant genes associated with autism spectrum disorders. We previously showed that Foxp1 and Foxp2 both have significant contributions to cortical and striatal development. We linked these developmental changes via studies of gene expression, electrophysiology, and behaviors. We further identified non-cell-autonomous changes in gene expression using newly available single-cell RNA- sequencing technology. Based on these data, the central hypothesis driving this proposal is that Foxp1 and Foxp2 are key orchestrators of transcriptional signaling cascades in a cell type-specific manner that are important for neuronal function and are at risk in neurodevelopmental disorders such as autism. We propose to identify these cell type-specific contributions in the developing cortex by using rodent models through three specific aims: 1) Determine the cell type-specific gene expression programs regulated by Foxp1 in the developing cortex; 2) Determine the cell type-specific gene expression programs regulated by Foxp2 in the developing cortex; and 3) Assess the role of Foxp1 and Foxp2 in cell type-specific activity-dependent neuronal function. Together, these aims will delineate the cell type contribution of both Foxp1 and Foxp2 to cortical development. The rodent models and cell-type specific genomic datasets will aprovide insight into the basic molecular mechanisms governing normal mammalian brain development.

Project Narrative Autism spectrum disorders is the most common, heritable, childhood-onset neuropsychiatric disorder. Understanding the genes and molecules critical for normal brain development will provide insight into the etiology of autism and related developmental brain disorders. These proposed studies will identify important genes for brain development and elucidate the functional and mechanistic role of specific genes in cortical development and physiology that can be targeted for the treatment of autism and other neurodevelopmental disorders.