The Sam68-hnRNP L protein interaction does not significantly impact on splicing regulation of two known target exons. (A) Minigene pETv5 contains the CD44 variable exon v5 cloned downstream of a constitutively-active RSV promoter. (C) Minigene pcDNA3-TJP1-WT contains TJP1 exon 20 downstream of a constitutively-active CMV promoter. (A and C) Splicing events are shown by broken lines, and arrows show the location of primers for RT-PCR. (B) HEK293 cells were transfected with the pETv5 minigene (150 ng), and expression vectors for hnRNP L-GST or GFP-Sam68 (500 ng). (D) HEK293 cells were transfected with pcDNA3-TJP1-WT (150 ng), and expression vectors for hnRNP L-GST or GFP-Sam68 (500 ng). (B and D) Gel images shown are representative of at least three independent experiments, from which densitometric assessment of RT-PCR product (lower panels) was performed to obtain means +/- standard error which are plotted in the bar chart. The lane marked M shows migration of the 1 Kb plus DNA ladder (Invitrogen).