FIGURE 7.

Antisense oligonucleotide directed against SL1induces Ψ-dependent tight dimerization of 1–561 RNA and vice versa. (A) Representation of the Ψ –SL1region and antisense oligonucleotides used in this experiment. The two palindromic sequences involved in dimerization are boxed. asΨ and asSL1antisense oligonucleotides binding sites are represented by thick lines. (B) 1–561 RNA was incubated in dimer buffer at 55°C without or with a 20-fold molar excess of asΨ, asSL1, or both oligonucleotides, and subjected to TBE electrophoresis. (C, D) Partitioning of asΨ or asSL1oligonucleotides in monomer or dimer species of 1–561RNA. The experiment described in B was repeated with one of the oligonucleotides radioactively labeled and present in a small amount and the other present in a 20-fold molar excess. In C, the gel is visualized with ethidium bromide and in D, the same dried gel is visualized by phosphorimager analysis to visualize the radioactivity associated with the labeled oligonucleotide.