Figure 4. Sequence features of autonomous and non-autonomous strong enhancers.

(a) Activity of library in the presence (x-axis) or absence (y-axis) of the Rho promoter. Dark blue, strong enhancers; light blue, weak enhancers; green, inactive; red, silencers; gray, ambiguous; horizontal line, cutoff for autonomous activity. Points on the far left and/or very bottom are sequences that were present in the plasmid pool but not detected in the RNA. (b–d) Comparison of autonomous and non-autonomous strong enhancers for information content (b), predicted cone-rod homeobox (CRX) occupancy (c), and frequency of transcription factor (TF) motifs (d).