(B) HEK293 cells were transfected with pCI SMN2 plasmid alone or in combination with plasmids encoding for RNA U1 decoy (D1), RNA U1 mismatch decoy with a variation in position +3 (D3), ExSpe U1 sm21, or AON 10–27. Total RNA was extracted and retrotranscribed with random primers. RT-PCR was performed with pCIF Fw and E8-75 Rev primers. The resulting amplified products were separated on 2% agarose gel. The identity of the bands is shown. Band intensity was quantified with ImageJ software and the percentage of exon inclusion is reported for each lane at the bottom of the gel, as mean ± SD of two different experiments.