Identification of SRSF2 as the main splicing factor responsible for FIX exon 5 recognition.

(A) Effect of overexpression of a panel of splicing factors on the splicing pattern in the FIX exon 5 wild-type and mutant minigenes (V107V and R116R). Minigenes were transfected in HeLa cells alone (NT) or with the indicated splicing factors and the splicing pattern evaluated by RT-PCR. The identity of the amplified bands with inclusion or exclusion of exon 5 is indicated. (B) Silencing of SRSF2 reduces the percentage of exon 5 inclusion in wild-type minigene. siRNA treated (+) and control HeLa cells (-) were transfected with wt minigenes and the resulting splicing pattern evaluated by RT-PCR. (C) Relative expression level of SRSF2 RNA, analyzed by qRT-PCR in siSRSF2 and control (si Luc) Hela cells. All data in the three panels represent the average of 3 replicates with error bars indicating SD.