XB-IMG-79044
Xenbase Image ID: 79044
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Knockdown of xSmad8 Dorsalizes Xenopus Embryos. (A) Whole-mount in situ hybridization for the pan-neural marker Sox2 in an uninjected control embryo, stage 22, dorsal view. (B) Injection of xSmad8 morpholino (0.5 mM, 4 nl injected four times radially) leads to expansion of the neural plate. (C) Control embryo stained for Otx2 (forebrain and midbrain marker) and Krox20 (hindbrain, rhombomeres 3 and 5), lateral view. (D) Smad8-depleted embryos are dorsalized (anti-BMP phenotype) and show expansion of head structures. It should be mentioned here that the original depletion of Xenopus laevis Smad8 by Miyanaga et al [30] yielded a very different result, namely apoptosis via activation of caspases. However, it should be noted that their methods for depletion were different. They used DNA oligonucleotides to deplete Smad8 transcripts in oocytes that were then subjected to maternal transfer and fertilization. We used morpholino oligos (of a different sequence) injected at the 4-cell stage, and therefore the depletion of maternal transcripts must have been less extensive. This explains why we did not observe apoptosis, but instead dorsalization (anti-BMP phenotype) of the embryo. The morpholino described here provides a useful reagent for knockdown of the maternal Xenopus laevis BMP-Smad. Smad8 probably corresponds to the homolog of zebrafish Smad5 [10] and is therefore referred to below as Smad5/8. Image published in: Eivers E et al. (2009) Eivers et al. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution license
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