Fig. 3

Increased CREB binding to CRE in GDNF enhancer II in GBM cells. a The binding of CREB to CRE in GDNF enhancer II in U251 cells as measured by in vitro EMSA. b The binding of CREB to CRE in GDNF silencer II and the effect of DNA methylation on the binding of CREB to CRE in GDNF silencer II in U251 cells as measured by in vitro EMSA. c The binding of CREB to CRE in different cis-acting elements of GDNF promoter II in U251 and NHA cells (n = 1), as assessed by ChIP-seq. The upper panel displays the peak value of CREB binding to part sequence (including the complete promoter II and part gene body of GDNF gene) in chromosome 5. The area demarcated with a dotted line denotes the 1154 bp fragment containing two CREs. The red and green boxes indicates the 50-bp region around CRE in enhancer II and silencer II, respectively; the peaks in the boxes indicate the binding signal of CREB to the regions; and the small blue box indicates the location of a portion of GDNF (n = 1). d, e The binding of CREB to CRE in different cis-acting elements of GDNF promoter II. f The relative binding to enhancer II in U251, U343, and NHA cells as determined by ChIP-PCR. Relative binding of CREB to enhancer II = binding of CREB to enhancer II/binding of CREB to silencer II (n = 3). All data except in (c) are mean ± SD. *P < 0.05; **P < 0.01