Fig. 5. Hormone inducible dominant-negative Sox9 construct. (A) Schematic representation of Sox9, Sox9C and Sox9C-GR fusion constructs. Sox9 lacking the transactivation domain (Sox9C) is fused to the ligand-binding domain of human glucocorticoid receptor (hGR). The HMG box is highlighted in blue, and the putative transactivation domain is underlined in red. (B) Western blot analysis of Sox9C-GR protein in extracts from Sox9C-GR-injected embryos collected at different stages. The fusion protein is expressed at similar levels at all stages (stage 10-20). This Sox9 antibody directed against the N-terminal domain of Sox9 does not allow detection of endogenous Sox9 protein (control, uninjected embryo). Tubulin is presented as a loading control.