shRNA knockdown was maintained in the presence of high levels of COMP.

<p>COS-7 cells with and without 3B shRNA integrant were infected with a DOX-inducible MT-COMP adenovirus. DOX dosage ranging from 1 ng/ml to 10 µg/ml was used. Protein lysate was collected 48 hours after adenovirus infection. (<b>A</b>) Western blot analysis of COMP expression in the absence of shRNA 3B. (<b>B</b>) Western blot analysis of COMP expression in the presence of shRNA 3B.