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Fig. 5. Expansion of Shh and FoxA2 expressing domains in MO-injected embryos. Four-cell stage Xenopus embryos were injected with 20 ng of control MO (A,D,G,J,M), with 20 ng of DHCR7 MOs alone (B,E,H,K,N) or with 500 pg of DHCR7 rescue mRNA (C,F,I,L,O). Whole-mount in situ hybridization of the tailbud stage embryos microinjected with DHCR7-MOs shows expansion of floor plate as marked by FoxA2 (A-C) and Shh (D-O) expression. (B,E) DHCR7 MOs injected embryos expand FoxA2 and Shh expression domains in frontal nasal region, branchial arches and anterior gut endoderm. (M-O) Transverse sections of embryos indicated in D,E. (K) Ectopic expression of Shh was detected in the notochord region of DHCR7 MO injected embryos (40%, n=28). ave, anterior ventral endoderm; ba, branchial arches; fl, floor plate (arrowheads); fnr, frontonasal region; age, presumptive anterior gut endoderm. White arrowheads indicate ectopic Shh expression. |
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Fig. 6. Neural patterning modulated by DHCR7. (A) Schema of unilateral injection experiment. Eight-cell stage Xenopus embryos were unilaterally (right side) microinjected with 20 ng of control MO (B,E,H) or 20ng of DHCR7 MOs alone (C,F,I) or with 500 pg of DHCR7 rescue mRNA (D,G,J). Transverse section of whole-mount in situ hybridization of the tailbud stage embryos microinjected with DHCR7-MOs shows ventralization of neural tube as marked by Shh (B-D), Nkx2.2 (E-G), FoxA2 and Dbx1 (H-J) expression. Arrowheads indicate the dorsal expression limit of the indicated markers. (K) Summary of ventralization of neural tube by loss of DHCR7. |
