MmuEX0028109 @ mm9

Inferred from MBNL1 ortholog: The exon 7 region enhances MBNL1-MBNL1 dimerization properties

The presence of alternative ex.54nt always significantly elevated MBNL1 and MBNL2 protein levels (_2.7 and _4.0-times, respectively). There were marginal changes of the GFP-MBNL level for constructs carrying ex.36nt (_1.3-times) and ex.95nt (_0.8-times). There were no significant differences between the activities of the analyzed proteins for the majority (67%) of AS events. However, these exons might have either a positive or negative effect on some specific AS events (Figure 5A and C). Interestingly, exOFF events predominated in AS events with a negative effect of ex.36nt (95%; P = 0.002) and a positive effect of ex.95nt (90%; P = 0.010). All together, these data indicate that the presence of sequences encoded by these alternative exons can significantly modulate MBNL splicing activity, but this regulation depends strongly on the targeted RNA.