Figure 6.

ECM1 is a PTHrP-inducible protein in chondrogenesis. A) PTHrP elevated RNA level of ECM1 in a time-dependent manner as measured by real-time PCR. ATDC5 and C310T1/2 cells were cultured in absence or presence of PTHrP for indicated time points, and real-time PCR was performed. Experiments were carried out in biologic replicates (n = 3). B) PTHrP elevated protein level of ECM1 in a time-dependent manner assayed by Western blotting. ATDC5 cells were cultured as described in panel A, then total protein was collected and Western blotting was performed against ECM1. β-Tubulin was used as an internal control. C) Deficiency of PTHrP resulted in specific loss of ECM1 expression in growth plate cartilage (red boxes) but not bone tissue (black boxes). Tibias were collected from both WT and PTHrP KO mice, and immunohistochemistry for ECM1 was performed. Brown color indicated the expression of ECM1. Values are means ± sd. *P < 0.05 vs. PBS treatment group.