Figure 3.

A closer look at the reprogramming factors Oct4, Sox2 and Klf4. (a) Important domains of each reprogramming factor, with DNA-binding domains indicated by colored boxes, and transactivation domains underlined in red. HMG, high-mobility group; POU, helix-turn-helix. (b) Reprogramming factor DNA-binding motifs determined by de novo motif discovery. (c) Phylogenetic trees showing the evolutionary relationships between each reprogramming factor and its respective paralogs, based on sequence comparison of their DNA-binding domains. Colors highlight family members that have been tested in the reprogramming assay and are able (green) or unable (red) to mediate reprogramming [15].