Figure 2: p300 differentially regulates transcription of GFAP and Nestin genes.

U251 (A) and U87 (B & C) cells (1×10⁶) were transfected with 2 µg GFAP-Luc (A & B) or 2 µg Nestin-Luc (C) reporter constructs along with indicated amounts of p300 or empty control vector (A, B & C). Luciferase activity was measured at 72 h after transfection. (D) 2×10⁶ cells treated with 20 ng/ml of IL-6 or 100 ng/ml of EGF for 30 min and subjected to ChIP using anti-p300 or matched IgG antibodies. p300 occupancy to the GFAP promoter was determined by PCR using radio-labeled primers and product densities plotted as ‘percent of input’. U251 (E & F) and U87 (G) cells (1×10⁶) were transfected with two different p300-shRNAs (Sh#1 and Sh#3) or 2 µg empty vector along with 2µg GFAP-Luc (E) or Nestin-Luc (F & G) reporter constructs. The promoter/enhancer activity was determined at 72 h posttransfection by luciferase assay. Normalized percent luciferase values are plotted as mean ± SE (n = 3). * and ** indicate p < 0.05 and p < 0.01 respectively.