Freshly isolated RPE sheets from ERKOα (lane 2), ERKOβ (lane 4) and their respective wildtype littermates (lanes 1 and 3) were subjected to zymography (A) and reverse zymography (B) as described in methods. Both pro (upper arrowhead, 68kDa) and active MMP-2 (lower arrowhead, 62kDa) increased in ERKOα RPE sheets compared to littermate controls and to ERKOβ sheets. TIMP-1 (upper arrowhead, 30kDa), 3 (middle band, 24kDa) or 2 (lower arrowhead, 28kDa) did not differ. n=2 eyes/group. The experiment was repeated two times on separate mice. M=standard.