Xenbase Image ID: 24379

Fig. 2. Localized expression of Wnts induces a polar AP neural pattern at long range in animal caps. (A) Experimental design: at the eight-cell stage, albino embryos were injected with 0.25 ng/blastomere noggin mRNA and pigmented embryos were injected with Xwnt3A mRNA (B) or pCSKA-Xwnt8 (C) into the four animal blastomeres. Animal caps were explanted at late blastula stage and sandwiched to yield pigmented/unpigmented conjugates. The conjugates were cultured until control siblings reached stage 15 and marker gene expression was analysed by in situ hybridization. Between 12-40 conjugates were analysed in B,C, of which representative samples are shown with albino halves of the conjugates always pointing to the top. (B) Animal cap conjugates from uninjected or Noggin-injected albino embryos and pigmented embryos injected with nil, 0.1 (+) or 1 ng/blastomere (++) Xwnt3A mRNA were analysed for the expression of Bf1, En2 and Krox20 as indicated. Note that in d′′ an organized AP pattern is generated with the more posterior Krox20 closer to the pigmented cap than En2. (C) Animal cap conjugates from uninjected or Noggin-injected albino embryos and pigmented embryos which were uninjected or injected with 0.05 ng/blastomere pCSKA-Xwnt8 were analysed for the expression of Bf1 and En2 by in situ hybridization. Image published in: Kiecker C and Niehrs C (2001) Copyright © 2001. 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

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