Increased Wnt/β-catenin signaling directly regulates Sox1 promoter activity during neural differentiation. (a) Schematic representation of binding sites for TCF/LEF transcription factors in a 3 kb promoter region of the Sox1 gene. Three pairs of PCR primers were designed based on potential TCF/LEF binding sites. (b) ChIP analysis of the mouse Sox1 promoter with β-catenin, TCF1, or TCF3 antibodies. β-catenin and TCF1 bound to the Sox1 promoter from day 4 during neural differentiation.