Modulation of CLK1 exon 4 splicing by tagged SR proteins. (A) Representation of the alternative splicing unit of CLK1 exon 4. The position of primers used for end point RT-PCR is indicated. (B) HCT116 cells transfected with the HA-SR plasmids were tested for HA-SR expression by immunoblotting with an anti-HA antibody. (C) End point RT-PCR was carried out to monitor endogenous CLK1 exon 4 inclusion. PSI values obtained for each sample were compared with the HA-EMPTY plasmid to obtain ΔPSI values, which are represented in the graph. Statistical significance was evaluated using multiple t-test analysis (GraphPad Prism software, version 10.2.2). (*) P < 0.05, (**) P < 0.01, and (***) P < 0.001. Gel triplicates for each sample displaying the RT-PCR reactions are shown in Supplemental Figure S1A.
