Construction of designer exons. (A) Cartoons of E, N, and S modules showing single-stranded ends used for ligation, along with the actual sequences. (B) Color-coded examples of possible designer exons (green, ESE; red, ESS; gray, neutral) along with the abbreviated notation used (E, S, N). Note that the abbreviated notation does not indicate the neutral 8-mer that lies between each E and S module and at each end. (C) Diagram of a designer exon within the test minigene used. Exon 1 is exon 1 of the Chinese hamster dhfr gene, exon 3 comprises the fused exons 4 to 6 of the dhfr gene. The 3′ and 5′ splice sites (SS) are from dhfr introns 1 and 3, respectively. (D) Z-score profile of all 8-mers in a possible designer exon (EESSEESE). The E and S modules generate salient signals over an otherwise unremarkable landscape.
