Sry and Nr5a1 bound at the TES enhancer upstream of the Sox9 gene (Sekido and Lovell-Badge 2008) and other enhancers (Gonen et al. 2017) activate transcription of Sox9 (Kidokoro et al. 2005, Sekido and Lovell-Badge 2008, Matoba et al. 2008, Gonen et al. 2017). Later in development, expression of Sry ceases and Sox9 activates expression of its own gene (Sekido and Lovell-Badge 2008). Dmrt1, itself directly activated by Sox9, also directly activates Sox9 (Matson et al. 2011, Lindeman et al. 2015). Fgf9 acting through Fgfr2 and Prostaglandin D2 activate Sox9 through less well characterized mechanisms (Kim et al. 2006).