Figure 7.
Model for secondary structure-dependent splicing. (Left) Zebrafish (AC)m-(GT)n introns: 5′ ss and 3′ ss are brought closer by base-pairing of AC and GT repeats. This intronic bridging can override the requirement of U2AF2 for 3′ ss recognition. (Right) Human (GGG)m-(CCC)n introns: 16% of human introns contain multiple copies of complementary G and C triplets near 5′ ss and 3′ ss, respectively, that stabilize the intronic structure. They may bridge the splice sites and facilitate splicing as the zebrafish (AC)m-(GT)n introns.
