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. 2023 Feb 2;24(3):2942. doi: 10.3390/ijms24032942

Figure 1.

Figure 1

Figure 1

Schematic representation of the OPN gene and its transcripts. (A) OPN encoding gene located on human chromosome 4q22.1. The gene is 14,762 bp long and contains 7 exons. (B) OPN splice variants. The OPN primary transcript is processed by the alternative splicing resulting in at least five variants: OPN-a contains 7 exons and is known as the canonical isoform; OPN-b lacks exon 5 (green box); OPN-c lacks exon 4 (blue box); OPN-4 lacks both exon 4 and exon 5 (blue and green boxes); and OPN-5, which has an extra exon (red box), resulting from the retention of an intronic portion between exon 3 and exon 4, being the longest OPN splice variant. OPN-5 starts its translation at an alternative site located in the extra exon. (C) OPN-5 subvariants. OPN-5a is the OPN-5, as described above; OPN-5b has the extra truncated exon; OPN-5c has an additional 9 bp in the 3’ region in the extra exon (red box surrounded by a bolded black line); OPN-5d has an additional 9 bp in the 3’ region in the extra exon and deletion of exon 5; OPN-5e lacks exon 5. This Figure was partially based on information provided in previous reports [9,11,12].