COMP mRNA expression is decreased in a dose-dependent manner in primary PSACH chondrocytes with three different COMP mutations infected with increasing MOIs of adenovirus expressing Ribo56. PSACH chondrocytes heterozygous for WT COMP and one of three COMP mutations (D469del, G427E, or D511Y) were isolated as previously described and were infected with increasing MOIs of AdRibo56. RNA was collected after 96 h. Total RNA (7 μg) was subjected to Northern analysis using radiolabeled probes specific for COMP and human GAPDH (loading control). Representative autoradiographs (N = 3) are shown above, while normalization of COMP mRNA knockdown is displayed in the bar graph. COMP expression in uninfected cells (0×) was normalized to 1. Error bars represent the SEM, and P < 0.05 was considered significant. (*) P ≤ 0.01 versus wild type; (#) P ≤ 0.01 versus D469del; (§) P ≤ 0.01 versus G427E.
