Forkhead box protein p1 is a transcriptional repressor of immune signaling in the CNS

Forkhead box protein P1 (Foxp1), a transcription factor showing highly enriched expression in the striatum, has been implicated in CNS development, but its role in the mature brain is unknown. In order to ascertain functional roles for Foxp1 in the CNS, we have identified gene targets for Foxp1 in vitro using gene expression microarrays and chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) assays. Transcriptome-wide analysis of Foxp1-transfected striatal cells revealed widespread expression changes of genes related to immune signaling, cancer, transcriptional regulation, and a curated Huntington’s disease (HD) signaling pathway. Integrating the microarray expression dataset with Foxp1 binding sequences determined from ChIP-seq analysis resulted in 75 direct targets of Foxp1, which included Foxp1 itself, which were also related to immune processes and the category “genetic disorder”. These findings demonstrate that Foxp1 is a primary transcriptional repressor of immunological-related gene expression in striatal cells. n=3 wt STHdh striatal cells and n=3 Foxp1-transfected STHdh striatal cells