Figure 1.

A schematic representation of the MMP9 gene and protein organization. The exons are indicated by the numbered grey rectangles. The 5′-untranslated and 3′-untranslated regions (UTR) are indicated by white boxes. The 5′-flanking region includes relative positions of key transcription factor binding sites. The domain structure of the MMP9 protein starts from a signal peptide (lilac square), followed by a propeptide (blue rectangle). An O-glycosylated (OG) domain (red rectangle) is located between a catalytic domain and a hemopexin (PEX) domain (green rectangle); it comprises a zinc-binding active-site motif (Zn) and tree fibronectin-like (Fn II-like) repeats.