Fig. 3

ATF6 stimulates chondrogenesis in vitro. Comparisons of ATF6 and BMP2 in stimulations of chondrogenesis of ATDC5 cells (a–c) and C3H10T1/2 cells (d–f). Micromass cultures of ATDC5 and C3H10T1/2 cells were incubated in the absence (CTR, Ad-GFP, serves as a control) or presence of either 300 ng/ml BMP2, Ad-ATF6 (MOI = 50), or Ad-ATF6 (MOI = 50) + BMP2 for 3 or 7 days, and the mRNA levels of Col II (a, d), Col X (b, e), and MMP13 (c, f) were determined using real-time PCR. The units are arbitrary, and the normalized values were calibrated against control (CTR), here given the value of 1. The asterisk indicates significant increase or decrease from control (*p < 0.05, **p < 0.01)