Splice junction confirmation via mass spectrometry. The confirmation of the splice junction between exon 10 (in blue) and exon 11 (in green) for the C. elegans gene C27C12.7 encoding a dipeptidyl peptidase (DPF-2) is illustrated. (A) The unspliced DNA sequence of C27C12.7 between the end of exon 10 and the beginning of exon 11. (B) Exon 10 and exon 11 spliced together. (C) The spliced exons separated into codons. (D) The peptide sequence spanning the splice junction and the representative mass spectrum. The numbers in blue above the peptide sequence represent the C-terminal y-ions and the red numbers below the peptide sequence represent the N-terminal b-ions. (Blue) y-ions; (red) b-ions; (green) all other ions (a-ions, doubly charged ions, ions from the loss of water or ammonia, etc.).
