Larger Image Fig. S5. Wnt2/2b/β-catenin/Tcf activity is required for Xenopus lung specification. (A) Embryos were injected in one dorsal-vegetal blastomere at the four/eight-cell stage with RNA encoding a hormone-inducible dominant-negative Tcf3 (GR-dNTcf3), which blocks β-catenin/Tcf-responsive transcription (Wnt LOF). Between stages 28 and 35, embryos were treated with or without 1 µM dexamethasone (dex) to activate the GR-dNTcf3. In situ hybridization at stage 35 shows that nkx2.1, but not wnt2b or osr2 expression, is regulated by Tcf. (B) Osr1/2-MO embryos do not express either wnt2 or wnt2b. (C) Wnt2/2b are redundantly required for nkx2.1 expression. X. tropicalis embryos were injected at the four/eight-cell stage in both dorsal-vegetal blastomeres with 20 ng each Wnt2-MO + Wnt2b-MO or 40 ng control MO and assayed at stage 35 for the indicated genes or at stage 42 gut tubes were isolated and assayed for sftpc. Numbers of embryos with the shown phenotype are indicated. Abbreviations: lpm, lateral plate mesoderm; fg, foregut. Image published in: Rankin SA et al. (2012) Copyright © 2012. 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.
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