Fig. 8. Misexpression of Fez or Fezl affects rostro-caudal polarity in the diencephalon. Misexpression of Fezl (A-Q) or Fez (R-U) by the 2.7 kbp Fezl enhancer/promoter (Fezl2.7p-Fezl-IRES-Venus, Fezl2.7p-Fez-IRES-Venus), or Fezl by the FM enhancer of the Otx2 gene and mouse Hsp68 promoter (Otx2FM-Hsp68-Fezl-IRES-Venus, V,W) affected the diencephalon subdivisions. Exogenous Fezl expression was monitored by the expression of Venus attached to an IRES (Fig. 7) (fluorescence images, A,D,G,J,L,O,R,T,V). E9.5 embryos were analyzed by whole-mount in situ hybridization with Foxg1 and Irx1 (B,C,S,W). E10.5 embryos were analyzed by in situ hybridization with Tcf4 (E,F,U) or Shh (H,I,K). Sagittal sections of E12.5 embryos were analyzed with Dlx1 or Gbx2 probes (M,N,P,Q). (C,F,I,N,Q) Control non-transgenic embryos. Expression of Foxg1 in the telencephalon was not affected (caudal limit marked by arrows), but the rostral limit of Irx1 expression (marked by arrowheads) was shifted caudally in Fezl2.7p-Fezl-IRES-Venus (B), Fezl2.7p-Fez-IRES-Venus (S) and Otx2FM-Hsp68-Fezl-IRES-Venus embryos (W), compared with the control (C). Tcf4-high expression domain in the thalamus and prethalamus was strongly reduced in the Fezl2.7p-Fezl-IRES-Venus (E) and Fezl2.7p-Fez-IRES-Venus (U) embryos. Shh expression in the ZLI (arrows) and ventral diencephalon was reduced (H, n=2/4), or Shh expression in the ZLI was shifted caudally (K, n=2/4) in the Fezl2.7p-Fezl-IRES-Venus embryos, compared with control (I). Dlx1 expression in the prethalamus was expanded caudally when the exogenous Fezl-IRES-Venus was strongly expressed (M, n=1/2). Gbx2 expression in the thalamus was strongly reduced in the Fezl2.7p-Fezl-IRES-Venus embryos (P, n=2/3).