Figure 7.

Rescue of splicing to SMN exon 7 by oligonucleotide 1 in vitro after mutation of GAA motifs. SMN2 is the normal substrate used for in vitro assays; ESE-M is an otherwise identical transcript in which the GAA repeats in exon 7 had been mutated and nucleotide 6 had been converted to the SMN1 nucleotide C. The pre-mRNA is the upper band in the triplet adjacent to the diagram of the pre-mRNA; the inclusion and exclusion mRNA isoforms are also marked. The oligonucleotides shown were used at 100 and 250 nM, as shown. Increased splicing to exon 7 is associated with increased intensities of a higher band corresponding to mRNA in which the second but not the first intron has been spliced, as noted previously (15).