Fig. 1
From: Meta-analysis of Osteopontin splice variants in cancer
Exon arrangement and splice variants of Osteopontin. Exon 1 in silent (untranslated), the other exons are depicted as black boxes. The full-length form, OPN-a, is depicted in the top row. The alternatively spliced exons 4 and 5 generate the isoforms OPN-b, -c and -4. Uniquely, the form OPN-5 retains an extra exon (eex), located between the canonical exons 3 and 4, which conveys an alternative translation start (due to this, OPN-5 constitutes a larger protein)