Figure 1.

HIF-1α regulates YY1 transcriptional activation by direct interaction with its promotor. (A) Three potential binding sites for the transcription factor HIF-1α obtained after bioinformatics analysis using two online servers, JASPAR and TRANSFACT, are displayed. The region from −2000 to +350 bp in the YY1 gene was analyzed for Transcription Start Site (TSS). A weight matrix obtained from the JASPAR database for the transcription factor HIF-1α is displayed. (B) Putative binding HIF-1α sites in the YY1 promoter that are involved in regulating expression. Transfection assays were performed using the PC3 cell line to assess the effects of directed mutagenesis at each of the YY1 binding sequences, located at sites −622 bp, −592 bp and +199 in the promoter region of the YY1 gene. The schematic shows each of the mutated sites, and the graph indicates normalized luciferase reporter gene expression levels obtained by measuring β-galactosidase via co-transfection with a reporter gene plasmid; fold changes are reported. The results are representative of three independent experiments (one-way ANOVA, * p < 0.005, ** p < 0.001). (C) ChIP was conducted for each potential HIF-1α binding site in the YY1 promoter. The results show that HIF-1α binds the promoter region of YY1. Results of three independent experiments are shown.