XB-IMG-41546
Xenbase Image ID: 41546
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Fig. 2. Meis3 restores posterior neural cell fates in the absence of canonical Wnt signaling. (A) In situ hybridization of mid-late neurula embryos injected at the one-cell stage with Dkk1 mRNA (35 pg; b,e,h,k,n) or, additionally, with Meis3 (0.25 ng) and β-gal (25 pg) mRNAs into one blastomere at the two-cell stage (c,f,i,l,o). All embryos are viewed dorsally, and oriented with anterior at the top, posterior at the bottom. The Meis3-injected side is on the right, as traced by the light blue/bright pink X-Gal staining. Dashed lines indicate the dorsal midline; bars indicate the posterior limits of gene expression on either side of the embryo. c′, i′, l′ and o′, show more clearly the signal in embryos treated as in c, i, l and o, respectively, but with no β-gal. XAG1 and XAnf1 expression undergoes robust posterior expansion in Dkk1 embryos (b, 113/115 embryos; e, 30/30 embryos), which is inhibited by Meis3 co-expression (c,c′, 73/81 embryos; f, 32/39 embryos). Posterior neural marker expression, Krox20, N-Tub and FoxD3, is inhibited in Dkk1 embryos (h, 78/80 embryos; k, 40/41 embryos; n, 51/52 embryos), but is strongly rescued by Meis3 co-expression (i,i′, 90/106 embryos; l,l′, 43/62 embryos; o,o′, 36/63 embryos). (B) In situ hybridization of mid-late neurula embryos injected at the one-cell stage with either Wnt3a-MO (50-60 ng; b,e,h,k,n), or, separately, with both Wnt3a-MO (50-60 ng) and Meis3 mRNA (0.5 ng; c,f,i,l,o). XAnf1 expression is posteriorly expanded in Wnt3a-morphants (b, 31/31 embryos), and suppressed by Meis3 co-expression (c, 55/55 embryos). Expression of the posterior neural markers Krox20, HoxB3, N-Tub and FoxD3 is inhibited in Wnt3a-morphants (e, 31/33 embryos; h, 31/31 embryos; k, 51/52 embryos; n, 50/51 embryos), but rescued by Meis3 co-expression (f, 29/33 embryos; i, 10/29 embryos; l, 22/39 embryos; o, 11/38 embryos). (C) In situ hybridization of late gastrula-early neurula siblings of embryos in A. All embryos are viewed dorsally, and oriented with anterior at the top, posterior at the bottom. The Meis3 injected side is on the right (bright pink X-Gal staining). Dashed lines and bars are as in A. Panels c′, f′, i′, embryos treated as in c, f, i, respectively, but with no β-gal. Otx2 expression undergoes robust posterior expansion in Dkk1 embryos (b, 49/51 embryos), which is inhibited by Meis3 co-expression (c,c′, 48/64 embryos). Expression of the posterior neural markers HoxD1 and Gbx2 is inhibited in Dkk1 embryos (e, 53/53 embryos; h, 51/53 embryos), but is strongly rescued by Meis3 co-expression (f,f′, 58/72 embryos; i,i′, 41/64 embryos). (D) Morphology of mid-late neurula embryos injected at the one-cell stage with either Wnt3a-MO (b, 70 ng), or Meis3 mRNA (c, 0.7 ng), or both (d). Neural folding and convergence extension is inhibited in Wnt3a morphants (b, 60/64 embryos); Meis3 co-expression rescued this phenotype (d, 48/49 embryos). Image published in: Elkouby YM et al. (2010) Copyright © 2010. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View |