FIG. 5.

Nuclear export of excised intron lariats harboring TBE in Xenopus laevis oocytes. Xenopus oocyte nuclei were injected with a mixture of ³²P-labeled U6Δss and U1ΔSm RNAs transcribed in vitro and the precursor RNAs as indicated on the top. RNA samples from total oocytes (T) or cytoplasmic (C) or nuclear (N) fractions were collected 3 h after injection. Products of the splicing reaction were resolved on 10% acrylamide–7 M urea denaturing gels. The positions of the mature products and intermediates of the splicing reaction are indicated. The asterisks indicate the positions of RNA molecules that are likely to be originated by degradation of the intron lariat and of the precursor RNA. Similar results were obtained in three independent experiments.