Foxp1 expression in forebrain pyramidal neurons controls gene expression required for spatial learning and synaptic plasticity

Genetic perturbations of the transcription factor, Forkhead Box P1 (FOXP1), occur in patients with autism spectrum disorder who have an increased risk for comorbidity with intellectual disability. Recent work has begun to reveal an important role for Foxp1 in brain development, but the brain region-specific contribution of Foxp1 to autism and intellectual disability phenotypes has yet to be fully determined. Here, we characterize Foxp1 conditional knockout (Foxp1cKO) mice with loss of Foxp1 in the pyramidal neurons of the neocortex and the CA1/CA2 subfields of the hippocampus. Foxp1cKO mice exhibit behavioral phenotypes that are relevant to autism spectrum disorder, including hyperactivity, increased anxiety, and decreased sociability. In addition, Foxp1cKO mice have gross deficits in learning and memory tasks that are relevant to intellectual disability. Using a genome-wide approach, we identified genes differentially expressed in the hippocampus of Foxp1cKO mice that are associated with synaptic function and physiology that could represent molecular networks related to the observed behavioral deficits. Finally, we observed reduced maintenance of long-term potentiation in the CA1 subfield of these animals. Together, these data suggest that expression of Foxp1 in pyramidal neurons of the forebrain is important for regulating gene expression pathways that contribute to specific behaviors relevant to autism and intellectual disability. In particular, Foxp1 regulation of gene expression in the hippocampus appears to be crucial for normal CA1 physiology and spatial learning. We carried out RNA-sequencing on adult male mouse hippocampal tissue and neocortical tissue. We compared gene expression profiles from Foxp1cKO mice to littermate controls, using four independent replicates per genotype.