FIGURE 8.

Stacking interactions at Repeat 7 are important for binding. (A) FBF-2, highlighting the region around H454 of Repeat 7 (Wang et al. 2009b). (B) Specificity testing of FBF-2 H454 (WT) and H454A with four different RNAs. (Top left) Core elements of RNA sequences tested in the three-hybrid assay; (top right) a diagram of RNA bases (ellipses) and stacking residue (dark gray rectangle) tested. RNAs with base substitutions (gray) at +2 were analyzed for binding with FBF-2 H454 (WT) and H454A in the three-hybrid assay. The WT RNA base is indicated in uppercase on the x-axis of the bar graph and mutant RNA bases in lowercase. β-Galactosidase activity reflects strength of the interactions (Hook et al. 2005). (C) Representative EMSA of purified FBF-2 H454 (WT) and H454A with gld-1 FBEa RNA.