FIGURE 1.

Both BBF2H7 and Sox9 are expressed in resting chondrocytes and proliferating chondrocytes, but not in hypertrophic chondrocytes. A and B, in situ hybridization of (A) Bbf2h7 and (B) Sox9 in the serial sections of tibia at E18.5 mice. Both Bbf2h7 and Sox9 were expressed in resting chondrocytes and proliferating chondrocytes, but not in hypertrophic chondrocytes in the developing cartilage. RZ: resting zone, PZ: proliferating zone, HZ: hypertrophic zone. Bars: 100 μm. C, Western blotting of BBF2H7 in mesenchymal stem cells maintained in micromass culture for the indicated days. Note that the expressions of BBF2H7, Sox9 and its target Col2 were transiently up-regulated on days 3 and 6 with a subsequent reduction. In contrast, the expression of Col10, a hypertrophic chondrocyte marker, was induced on day 9.