MMP9 and cataract: Furthermore, the analysis of TGF-β-responsive genes by RT-qPCR showed increased expression of collagen (COL1A1), fibronectin (FN1), Snail, matrix metalloproteinase 2 (MMP2), and matrix metalloproteinase 9 (MMP9) (Figure 3(b)) in the cataracts of transgenic mice as compared to nontransgenic lens samples.