Fig. 4. Increased transcriptional activity and selective gene response in Timp3^–/– MECs. (A) -catenin transcriptional activity was measured using pTOPFLASH/pFOPFLASH luciferase reporter assay and was significantly higher in both Timp3^–/– MEFs (^*P=0.001; , WT; , Timp3^–/–) and Timp3^–/– MECs (^**P=0.01) compared with their respective WT controls. Relative light unit values were normalized against a -galactosidase transfection control. (B,C) Expression of -catenin target genes was assessed by TaqMan real-time PCR and are normalized to 18S RNA values for each sample. (B) Ccnd1 mRNA level was significantly lower in both Timp3^–/– MEFs (^*P=0.05) and Timp3^–/– MECs (^**P=0.002). (C) Mmp7 mRNA level was significantly increased only in Timp3^–/– MECs (^*P=0.005). Two-tailed, Student's t-test was performed to assess statistical significance between WT and Timp3^–/–. Values are expressed as mean ± s.e.m. of three independent experiments.