Fig. 5. Misexpression of Hoxa3 in the rostral hindbrain. (A) Flat mount of mouse hindbrain (E10.5) in situ hybridised for mouse Hoxa3. (B,C) Dorsal view of a chick head electroporated on the left side with tauGFP/Hoxa3 at stage 10 and incubated until E4, showing co-localisation of GFP fluorescence (B) and in situ hybridisation for Hoxa3 (C). (D-I) Flat mounts of E4 chick hindbrains electroporated at stage 12 (D-G) or 17 (H,I) with Hoxa3/tauGFP, and in situ hybridised for Hb9. Double-headed arrow indicates Hb9 induction. E and F are higher magnifications of D and G, respectively. (I) Same embryo as H following immunostaining for GFP protein to show the area of electroporation. Note that at stage 17 no Hb9 induction was observed following electroporation of tauGFP/Hoxa3. (J,K) Flat mounts of the same E6 chick hindbrain electroporated with human HOXB3/tauGFP at stage 11, in situ hybridised for Hb9 (J) and immunostained for GFP (K). Note that no induction of Hb9 was observed. Scale bar: 580 µm for A-C; 420 µm for D,G; 250 µm for E,F; 300 µm for H,I; 500 µm for J,K.