Upper, diagram of the exons (boxes) and introns (horizontal lines) of the splicing reporter mini-gene DUP175ST and its CaRRE1 in the upstream 3′-splice site of STREX (heavy line). In reporters L1 or L1m, the CaRRE1 was replaced with the hnRNP L high affinity CA repeats (L1) or low affinity sequence (L1m). Arrowheads, locations of PCR primers. Lower, an agarose gel of RT-PCR products from RNA samples of HEK293T cells co-transfected with each of the above splicing reporters and kinase-dead mutant (IVm) or constitutively active CaMKIV (IV), with average percentages (±S.D.) of exon inclusion under each lane, exon-included or -excluded products indicated to the right, and molecular size makers (M) to the indicated to the left. NC, PCR negative control. *, likely product from pre-mRNA. **, a cryptic 3′-splice product from 65 nt downstream in the middle exon.