Figure 1.

Activities of 54 variable length TALE activators targeted to the endogenous human VEGF-A gene. (a) Schematic depicting the human VEGF-A promoter region. The transcription startpoint is indicated with a black arrow and previously published DNase I hypersensitive regions¹³ are shown as grey bars. The DNase I hypersensitive region located between positions +400 to +650 relative to the transcription start site has been expanded, with red arrows indicating the locations and orientations of the 26 bp sites bound by the longest length TALE-activator (harboring 24.5 TAL effector repeats) in each set. (b) Activation of VEGF-A protein expression in 293 cells by 54 variable-length TALE activators. Cells were transfected in triplicate with plasmids encoding each TALE-activator and then assayed as described in Methods. Mean fold-activation values are shown with error bars representing standard errors of the mean. All activators tested (except the 14.5-repeat activator from set 7) induced fold-activation of VEGF-A expression to a value significantly greater than 1, as determined by a one-sided, paired t-test (P < 0.05).