The minigene STREX splicing construct pDUPST1

(A) The STREX insert replaces DUP4-1 sequences between the ApaI and BglII sites. The CMV promoter, primer extension primer DUP1 (arrows), exons (boxes), introns (lines), and regulatory elements are indicated. They transfected this plasmid into HEK cells with or without a plasmid expressing active forms of CaMK to test for the effect of the kinase on alternative splicing of the STREX exon. (B) Primer extension assay with CaMK IV. M, nucleotide size marker; mock transfection (lane 1); 4-1, pDUP4-1 (lane 2); pDUPST1 (lane 3); IV, pDUPST1 cotransfected with a plasmid expressing CaMK IV-dCT (lane 4). The sizes of the spliced and unspliced forms are indicated on the right side of the figure. Asterisk indicates apparently early terminated products from unspliced mRNA.