Kelly LE , Nekkalapudi S , El-Hodiri HM .

EY015480 NEI NIH HHS , R01 EY015480-03 NEI NIH HHS , R01 EY015480-01 NEI NIH HHS , R01 EY015480-02 NEI NIH HHS , R01 EY015480-02S1 NEI NIH HHS , R01 EY015480-04 NEI NIH HHS , R01 EY015480-05 NEI NIH HHS , R01 EY015480 NEI NIH HHS

Fig. 2. FoxN4 is expressed in developing eye fields, brain, and retinal progenitor cells. (A–J) Detection of FoxN4 (A–E) and Rx (F–I) expression in neural plate (st 16-A,F), neural tube (st 19-B,G) and tailbud (st 25-C,H; st 31-D,E,I) embryos by wholemount in situ hybridization (WISH) using antisense riboprobes. Arrow in I denotes pineal gland. (E) high magnification view of pronephric area from an embryo similar to that shown in D (box) but subjected to reduced proteinase K treatment and prolonged color reaction. (J) Comparison of FoxN4 and Rx expression in a st 19 embryo visualized by double in situ hybridization using antisense probes for FoxN4 (turquoise color) and Rx (magenta color). Arrowhead denotes region of Rx single staining. J′: digital enlargement of left eye region in J to more clearly show Rx expression (arrowhead). (K–N) Analysis of FoxN4 expression in the developing brain of whole Xenopus embryos at neural tube and tailbud, at indicated stages. (O–T) Analysis of FoxN4 (O–S) and Rx (T) expression in sections obtained from paraffin-embedded fixed embryos at early tadpole stages. Arrowheads in R, T indicate the tips of the CMZ. Abbreviations: C, cement gland; CMZ (bracket), ciliary marginal zone; E, eye; FB, forebrain; HB, hindbrain; L, lens; MB, midbrain; O, olfactory bulb/placode/organ; R, retina.

Fig. 3. Expression of X. laevis FoxN4 in the tadpole brain. Visualization of FoxN4 expression in isolated tadpole brains by WISH. Brains were isolated from fixed st 45 tadpoles and subjected to WISH using antisense riboprobes for FoxN4 (A–C), Lhx2 (D,E), Lhx5 (F,G), or Lhx9 (H,I) as indicated. Brain regions are labeled (abbreviations are explained in box). (A,D,F,H) dorsal views; (B,E,G,I) lateral views; (C) ventral views. (J) Simultaneous visualization of FoxN4 (turquoise) and Lhx9 (magenta) expression in the region of prosomere 2 by double in situ hybridization performed using an isolated st 45 tadpole brain. (J′) Section of brain shown in J. (K–M) Sections of isolated tadpole brains subjected to WISH using FoxN4 (K,L) or Lhx5 (M) antisense riboprobes. (N) In situ hybridization performed on a sectioned st 41 tadpole probed with an antisense Sox2 riboprobe. Red lines in B, G, and J indicate planes of section shown in panels J′, K, L, and M.

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