Figure 6. Linking of Sp3 with AFAP1L1 by siRNA experiments.

(A) The specificity of siRNA. U2OS cells were treated with siRNA targeting Sp1, Sp3, or Sp4 for 48 h, and the expression of these genes as well as the AFAP1L1 gene was analyzed by PCR. Two different siRNAs targeting the Sp1 and Sp3 genes were designed and used. β-actin was used as a control. (B) Down-regulation of AFAP1L1 expression by siRNA targeting the Sp3 gene at the mRNA level. U2OS cells were treated with siRNAs targeting each gene for 48 h and the expression of AFAP1L1 was analyzed by qPCR and indicated as fold changes relative to that in untreated cells. (C) Down-regulation of AFAP1L1 expression by siRNA targeting the Sp3 gene at the protein level. U2OS cells were treated with siRNA targeting each gene for 72 h and proteins were extracted and used for Western blotting. β-tubulin was used as a control.