FIGURE 2.

U2 and U12 dependence of β1-2 and Δβ1-5 RNA splicing. In vitro splicing reactions containing radiolabeled β1-2 (lanes 2–4) or Δβ1-5 RNA (lanes 5–7). Splicing reactions were carried out for 1.5 h in 50% Hela nuclear extract, and splice products were separated on 8% polyacrylamide gels containing 8 M urea, and splice products were visualized by autoradiography. Reactions in lanes 3 and 6 contained 2 μM Anti-U2 2′ O-methyl oligonucleotide and 2 μM anti-U12 2′ O-methyl oligonucleotide was added to lanes 4 and 7. Oligonucleotides were added to HeLa nuclear extract and preincubated under splicng conditions for 20 min prior to addition of splicing substrates. A 100-nt DNA ladder (New England Biolabs) was 5′ radiolabeled and used as a size marker in lane 1. The prominent band is 500 nucleotides in length.