Long-term activity of shRNA COMP knockdown was maintained over 2 weeks.

<p>COS-7 cells with shRNA 3B, 3A-A or 3A–C integrant were infected with an adenovirus expressing MT-COMP and protein lysate was collected at 2, 4, 7 and 14 days. (<b>A</b>) Western analysis of protein lysates of MT-COMP expression levels at 2, 4 and 7 days. After 14 days, appreciable amounts of COMP were not being produced (*). (<b>B</b>) Quantification of COMP protein levels from COS-7 cells expressing recombinant COMP in the absence of a shRNA was set to 100% (*a) and all other lanes were compared to this reference. Levels of β-actin were used to normalize protein loading.