Figure 3.

Intragenic trans-splicing reactions. A. Inverse RT-PCR experiments were performed for all investigated genes. Two oligonucleotides - pointing into opposite directions - were designed that specifically bind to a single exon located upstream of the bcr's. Subsequent RT-PCR experiments were performed using cDNAs of healthy volunteers. B. For all investigated genes, intragenic trans-splicing products were identified, cut-out from the gel, cloned and se-quenced. Left lane in all panel: size marker; Right lane in all panels: intragenic trans-splicing products (a-q). C. Sequence analyses of PCR species a-q revealed the exon-exon-fusions of all intragenic trans-splicing products (lower dashes between single exons indicate correctly spliced exon-exon boundaries in the identified trans-spliced transcripts. Exons designated with additional letters (e.g. Ex1b) are cryptic exons normally not used during regular splicing.