WT- and MT-COMP expression is decreased in a dose-dependent manner in COS7 cells cotransfected with increasing amounts of Ribo56 plasmid. COS7 cells were cotransfected with 250 ng of either pWT-COMP or pMT-COMP and increasing amounts of pRibo56. RNA and cellular protein were harvested 72 h after transfection. (A) Total RNA (7 μg) was subjected to Northern analysis using radiolabeled probes specific for COMP and human GAPDH (loading control). Representative autoradiographs (N = 6) are shown above, while normalization of COMP mRNA knockdown is displayed in the bar graph. COS7 cells expressing only COMP (0×) were normalized to 1. Error bars represent the standard error of sample means (SEM), and P < 0.05 was considered significant (*). (B) Protein (30 μg) was subjected to Western analysis of three independent experiments with pMT-COMP using antibodies specific for COMP and β-actin (loading control). Shown are the resulting autoradiographs and bar graph normalization of the results.
