Fig. 3. XHRT1, esr9, esr10, Xhairy1 and Xhairy2b are responsive to Notch signaling in the pronephric mesoderm (arrowheads). Whole-mount in situ analysis of stage 23-30 embryos injected with hGR/Su(H)/Ank or Su(H)DBM mRNA. The inducible construct was activated at stage 18. (A, parts a-t) Control and injected sides of embryos, anterior right. Note the posterior expansion of the expression of the different bHLH-O genes on the injected side of hGR/Su(H)/Ank-injected embryos (arrowheads). Note the inhibition of their expression in Su(H)DBM-injected embryos (arrowheads). Except in d,f,h and j, the injected side is revealed by ß-gal staining (red). (B, parts a-e) Transversal sections of the embryos shown in b,d,f,h,j at the level indicated. Note that the strongest esr9, esr10 and XHRT1 ectopic staining is detected in the lateral part of the intermediate mesoderm, while Xhairy1 and Xhairy2b expression is found in both layers (arrowheads). Xhairy2b is also strongly activated in the ectoderm (arrow). (B, part f) Transversal sections in stage 23 embryos in the posterior portion of the pronephros showing that XHRT1 ectopic expression in response to activation of Notch is already detected at that stage in both layers. (B, part g) Transversal section in the posterior portion of the pronephros of stage 23 embryos stained with xWT1. Ectopic staining of xWT1 is restricted to the medial layer.