|Supplementary Figure 3. Sequence requirements of the Hox/En complex.
a, EMSAs on the DMX-R1 probe using AbdA and En as indicated. An AbdA/En complex forms on the WT and X6, X7, and Hth probes, but is greatly reduced or eliminated by the Hox1w, Exds, and X5 mutations.
b, Close up view of the EMSA shown in Figure 4c. In the absence of En, AbdA/Exd/Hth, Exd/Hth/AbdA, and AbdA/Exd/Hth/AbdA complexes are observed on both wild type and x5 mutant probes. On the wild type probe (left hand panel), the addition of En results in a descrease in the amount of trimer (black arrowhead) and an increase in the amount of higher order complexes, including a complex that migrates more slowly than the AbdA/Exd/Hth/AbdA tetramer (white arrowhead). We suggest that these complexes include En/AbdA/Exd/Hth/AbdA pentamers and En/Exd/Hth/AbdA tetramers (indicated by the bracket). Importantly, none of these En-induced changes in complex formation are observed on the X5 mutant probe (right hand panel). In addition, the formation of the En/AbdA/Exd/Hth/AbdA complex is inhibited and partially supershifted (*) by the addition of anti-En antibody.