Xenbase Image ID: 79951

Fig. 1. Late blastula expression of Siamois is not sufficient to promote anterior development. (A,B) Embryos were injected at the four-cell stage with 20 pg/blastomere (bl) Siamois mRNA. (C,D) Embryos were injected at the four-cell stage with 100 pg/bl CSKA-Siamois plasmid DNA. In (B,D), cross-sections were counterstained with hematoxylin/eosin. Note that embryos injected with CSKA-Siamois plasmid DNA did not develop a head (100% of negative cases) but occasionally developed a notochord (50% of positive cases). (E) RNAse protection analysis of animal explants injected with the indicated amount of RNAs or 100 pg/bl CSKA-Siamois plasmid DNA at the two-cell stage. Animal caps (20 per probe) were dissected at stage 9 and incubated up to stage 28. The absence of mesoderm in the explants was assessed by the lack of muscle actin specific signal. FGFR1 expression served as a loading control. Siamois RNA but not DNA induced the anterior markers XCG1 (cement gland) and otx2 (forebrain/midbrain) as well as the neural cell adhesion marker N-CAM in a manner comparable to the neural inducer noggin (Nog). Siamois did not induce the en2 (midbrain/hindbrain boundary) and Hoxb9 (spinal cord) markers. Image published in: Kodjabachian L and Lemaire P (2001) Copyright © 2001. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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