FIGURE 4.

Oct4 is associated with the SOX2 enhancer region to up-regulate expression levels of Sox2 in glioma-initiating cells. A, effects of Oct4 knockdown on expression of Sox2. Amounts of Sox2 protein were determined after treatment with control (NC) or Oct4 siRNA #1 duplex for 24 h. α-Tubulin was used as a loading control. B, association of Oct4 with the SOX2 enhancer region. ChIP analysis was performed using TGS-01 cells (“Sphere”) and matched “Differentiated” cells. Eluted DNAs were subjected to conventional RT-PCR. The first intron of hypoxanthine phosphoribosyltransferase 1 (HPRT1) was used as a negative control. Input: 1%. C, levels of expression of Oct4 protein in “Sphere” cells and “Differentiated” cells. α-Tubulin was used as a loading control.