FIGURE 7.

Mbnl1 and SR proteins act independently to promote exon 11 inclusion. A, linker scanning LS2 or LS5 mutant minigene constructs were cotransfected with the Mbnl1 protein expression vector into HepG2 (upper panel) and HEK293 (lower panel) cells. hIRΔ164 deletion mutant was cotransfected with the SRp20 protein expression vector. Spliced products were analyzed as before. The mean percentage exon 11 inclusion (% IR-B ± S.D., n = 3) is shown. Asterisks indicate statistical significance (p < 0.05) versus empty vector control. N.D., not detectable. B, total cellular protein was extracted from Fao, HepG2, and HEK293 cells. Equal amounts of protein were loaded and immunoblotted for Mbnl1 and CUG-BP1. Blot was reprobed with β-tubulin as a loading control.