Figure 9.

Kethoxal probing of the ψ-SL1 in spliced and unspliced RNAs. (A) Primer extension reactions of kethoxal modified wild-type (lanes 1–4) or Rev-spliced (lanes 5–8) RNA were carried out as described in Materials and Methods. Overall, the reactivities in this region and elsewhere in the RNA (data not shown) were similar, indicating that gross rearrangements of the RNA did not occur upon splicing. However, several nucleotides in the ψ-SL1 region did display reactivity differences as indicated. (B) Summary of the principal reactivity differences between unspliced and spliced RNAs superimposed on a secondary structure model of ψ-SL1.