FIGURE 6.

Effects of mutations of snR85 (within the 5′ pocket) on Ψ1181 formation within the 18S rRNA. (A) Schematic representations of the 5′ pocket of snR81 base-paired with 18S rRNA. Depicted are base-pairing interactions between the wild-type (a) or various mutant (b–i) 5′ pockets of snR85 and the wild-type 18S rRNA substrate sequence. Italicized letters represent mutated nucleotides. Crosses (Xs) indicate disrupted base-pairing interactions. (B) Detection of Ψs in yeast 18S rRNA using CMC-modification followed by primer-extension. Pseudouridylation of 18S rRNA was carried out in the context of wild-type (lanes 1 and 2, and lanes 17 and 18) and various mutant (lanes 3–16, and lanes 19–22) snR85 (illustrated in A, b–i). Signal corresponding to Ψ1181 is indicated. Ψ1181 formation was quantified using the formula Ψ1181/(Ψ1181 + primer). The mutants (mutant lanes) were then normalized to the wild-type control. The final pseudouridylation efficiency numbers (Ψ1181%) are shown at the top of each lane.