Updated project metadata. Our study shows that deletion of the alternative splicing regulator PQBP1 in striatal progenitors resulted in defective striatal development due to impaired neurogenesis of spiny projection neurons (SPNs). Therefore, we further reveal that PQBP1 associated with components in splicing machinery by LC-MS/MS. These findings identify PQBP1 as a novel regulator in balancing striatal progenitor proliferation and differentiation.