Figure 4.

Ptbp2 binding upstream of alternative exons silences exon inclusion in vivo. Examples of high-density BC2 CLIP tag clusters predicting Ptbp2 action to repress exon inclusion. (A) Distribution of Ptbp2 CLIP tags to the Stam2 gene. Tag density is represented by a histogram where the black line indicates a CLIP tag density of 10 overlapping tags. (B) Zoom-in view of a high-density Ptbp2 CLIP cluster immediately upstream of the Ptbp2-dependent Stam2 alternative exon. (C) RT–PCR confirmation of aberrant (increased) splicing of Stam2 exon 2 in Ptbp2-null brains compared with wild-type littermate controls. (D) Distribution of Ptbp2 CLIP tags to the Actn1 gene. (E) Zoom-in view of Ptbp2 binding in the intron flanking the alternative NM and SM exons. (F) RT–PCR confirmation of a role for Ptbp2 in the regulation of Actn1 NM/SM splicing.