as548-Mediated tight dimerization of 1–561RNA lacking SL1and PBS dimerization sites. (A) 1–561 ΔSL1RNA was incubated at 55°C in dimer buffer with a 20-fold excess of as548, asDIM oligonucleotides, or both and subjected to electrophoresis on TBE gel. The 1–561ΔSL1RNA lacks the SL1structure (deletion of nt 409–436). (B) The experiment described in A was reproduced using asΨ instead of asDIM. The asΨ oligonucleotide is complementary to nt 380–404 (Table 1) and binds to the encapsidation signal Ψ. (C) The experiment described in B was reproduced with the 1–561ΔNAR1ΔSL1RNA. This construct lacks both SL1and the 5′-304-GGCGCC-309-3′ sequence located at the 5′ end of the primer-binding site shown previously to mediate loose dimerization of 1–561 RNA (Jossinet et al. 2001; Lanchy and Lodmell 2002). Loose dimers are not expected to withstand the TBE electrophoresis.
