Figure 9

Co-occurring pairs act synergistically to promote splicing. (a) Splicing of Hb2 exons in transient transfection experiments. The inset diagram is a schematic view of the minigene used. The central exon used to gauge inclusion was exon 2 of the human beta globin gene, including its splice site sequences. Five co-occurring pairs from the UpDp class were tested by inserting two tandem pentamers upstream and/or downstream of the exon. The pairs were: 1, TCCCT_GGAGG; 2, CCCCT_AGGGA; 3, TTTCT_TGGTG; 4, TTTCT_GGTGG; and 5, CGCCG_CGCGC. We also tested two neutral tandem pentamer motifs (N1 and N2) chosen not to resemble any known splicing motifs nor to create such by their insertion nor to create any significantly correlated motif pairs when inserted. U, upstream position; D, downstream position. (b) Splicing of WT1-5 exons (exon 5 of the Wilm's tumor gene 1). As (a) but with exon 5 of the Wilm's tumor gene as the central exon, and a different neutral control sequence, N3. (c) Diagram of the central exon region of exon body swapped minigenes. (d) Splicing of minigene transcripts with exon body swapped exons. Three co-occurring pairs from the UpDp class of alternative exon sets were also tested in this context. The three pairs were: A1, TGGGG:CTGGG; A2, CAGTG:CTTCT; A3, GGGCG:GCGCG. Note that splicing here is measured by percent skipping rather than inclusion. (e) Synergy index (SI) of tested pairs. A negative SI signifies synergy, a positive SI signifies anti-synergy and an SI of zero indicates a lack of synergy. Error bars are the standard error of the mean.