| |
Fig. 4. dkk1 regulates anteroposterior patterning of neurectoderm. (A,E,I) control embryos, (B,F,J) embryos injected radially at the four-cell stage with dkk1 (C,G,K) embryos injected with anti15 Ab into the blastocoel and (D,H,L) embryos treated with 10−7 M retinoic acid (RA). In situ hybridization for BF1 and En2 (A-D), Xanf1 (E-H), and XOtx2 (I-L). Midgastrula-stage embryos (stage 15) are shown from anterior, dorsal side up.
(M) Schematic diagram of the BF1 (dark green), Xanf1 (blue), XOtx2 (violet) and En2 (yellow) expression under the treatments indicated above. Note the changes in size of the head anlage and change in the proportions between its anterior and posterior regions. (N-U) dkk1 affects forebrain at the expense of midbrain, whereas RA affects both regions. (N-U) In situ hybridization for BF1 and En2 under the treatments indicated above. Brains of stained embryos were excised from 4-day embryos and are shown from the dorsal (N-Q) and lateral (R-U) sides, anterior side up. Note the expansion of tel- and diencephalon and reduction of mesencephalon in O and S and the opposite changes in P and T. di, diencephalon; mes, mesencephalon; rh, rhomencephalon; tel, telencephalon. |
