(A) HEK293T cells were transfected with a negative control siRNA (siC), or one of two independent siRNAs targeting SUGP1, followed by western blotting.
(B) RT-PCR products of the cryptic 3′ss (open arrowheads) and canonical 3′ss (solid arrowheads) of the indicated genes in HEK293T cells as in (A).
(C) Each of the indicated WT (shown in green) and mutant (shown in red) minigenes was cotransfected either with expression plasmid for HA-tagged WT (W) or K700E (K) SF3B1 (left panels), or with one of two independent siRNAs targeting SUGP1 (right panels) to HEK293T cells, followed by RT-PCR of the cryptic 3′ss (open arrowheads) and canonical 3′ss (solid arrowheads) from the minigenes. As indicated, an empty vector plasmid (Vec) and a negative control siRNA (siC) were also used.
See also Figures S2 and S3.