Fig. 7: PRC2 core components contributed to Utx depletion-mediated anabolic chondrocytic activity.

Gene track illustrating limited H3K27me3 chromatin occupation at regulator loci and promoter regions of Ezh2, Eed, and Suz12 genes in UtxKO chondrocytes (red) as compared to WT cells (blue) (a). Utx loss repressed the H3K27me3 enrichment at the Ezh2 promoter but increased that at the Eed and Suz12 promoters (b). It increased abundance of Ezh2, but reduced that of Eed, Suz12, and H3K27me3 (c). Evident Ezh2 immunostaining and weak Eed2 and Suz12 immunoactivity in UtxKO cartilage (d), scale bar, 10 μm. Forced Eed or Suz12 expression increased H3K27me3 levels (e, f) and H3K27me3 occupancy at the Sox9 promoter (g). Chondrocytic marker gene expression (h) and ECM production (i, j scale bar, 500 μm) in UtxKO chondrocytes were suppressed by forced expression of both components. Cells were transfected with Eed or Suz12 expression vectors or empty vectors. RT-PCR was conducted upon transfection for 24 h. Micromass for Alcian blue staining were incubated for 7 days. Cell cultures were harvested from three mice and experiments were repeated three times. Data are expressed as mean ± standard errors. *P < 0.05; **P < 0.001.