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. Author manuscript; available in PMC: 2014 Jul 15.
Published in final edited form as: Osteoarthritis Cartilage. 2011 Jul 29;19(10):1246–1253. doi: 10.1016/j.joca.2011.07.011

Fig. 1. Induction of COMP expression precedes that of Col2a1.

Fig. 1

(A) COMP mRNA is expressed before Col2a1 during chondrogenesis of BMSC pellet culture. Total RNA was isolated from primary human BMSC cultured as high-density pellet in chondrogenic media containing TGF-β1 for 3, 7, or 14 days. The mRNA expression levels of the COMP and Col2a1 were measured using quantitative RT-PCR and normalized to GAPDH. The values shown for each gene at a given time points were fold-induction relative to un-induced BMSC at day 0 (mean with 95% CI, n = 3). A CT value of >40 PCR cycle was deemed undetectable. *Student’s t-test comparing day 0 to day 3 (P = 0.0425), day 7 (P = 0.004), and day 14 (P < 0.0001). (B) COMP protein is detected earlier than Col2a1 during chondrogenesis. Human primary BMSC grown in pellet culture were treated with or without TGF-β1 for the indicated time points. The amounts of COMP and Col2a1 proteins recovered from cells and their associated extracellular matrix were detected by Western blot.