(B) Expression fold changes (ecdysone inducibility) versus measurements without ecdysone and grouped by native core promoter sequences. The colors refer to different core promoter architectures. Three types of line are used to indicate the expression fold change with no increase (y = x; solid line), 2-fold increase (y = x + 1; dotted line) and 4-fold increase (y = x + 2; dashed line). Red vertical dashed line: log2 basal expressions = 2. 