Figure 3.

Mutant human COMP accumulates in the rER of mouse chondrocytes. Growth plates from MT-COMP (A–C), WT-COMP (D–F) and C57BL/6 (G–I) mice at 1 month were fed 100 ng/ml of DOX and were immunostained for COMP (green) and CRT (red) as described in the methods and the images were merged. CRT is a resident ER chaperone protein and the COMP antibody recognizes both transgenic human COMP and endogenous mouse COMP. Mice expressing MT-COMP show intracellular retention of COMP co-localizing with CRT indicating that they are in the rER of the growth plate chondrocytes (C). No co-localization is observed with WT-COMP and CRT (F). Scale bar = 20 μmol/L.