FIGURE 6.

Mutation of the P6.1 hairpin loop sequence interferes with RNA complex formation between P6.1 and RNA33–147. (A) U7C and G9C introduce mutations at bases that are variable across vertebrate telomerase RNAs (Chen et al. 2000). RNA complex formation is observed, but at levels much lower than with wild-type P6.1 (wt), indicating that the RNA–RNA interaction is much weaker in the presence of the mutated hairpin. (B) G10C and U8C introduce mutations at 100% conserved bases and also show greatly reduced complex formation. The hairpin with mutation U8C dimerizes under nondenaturing conditions, indicated by bands with mobility between the free RNA and the complexed RNAs. (C) Mutation at P6.1 position G10 disrupts formation of the RNA–RNA complex. (D) A base-paired stem is required for interaction. RNA44–57 is 5′-end labeled. Mutant hairpin B does not form complex whereas hairpin C, with a restored stem, is able to interact with the template.