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FIG 3. Double-sided injection of a dominant inhibitory tinman construction eliminates the cellular movements associated with heart formation. Histological sections through the heart region of control and experimental stage 30 embryos assayed for TnIc expression. (A) Control embryo showing expression of TnIc in the developing heart tube. The myocardial layer has completely separated from the overlying endoderm and the underlying somatic mesoderm layers. The myocardial tube surrounds endothelial cells that will later form the endocardium. (B) Experimental embryo injected with 125 pg of Nkx2-5 LP mRNA on each side. No detectable expression of the myocardial marker TnIc is visible. In addition, there is no visible delamination of the tissue layers and no evidence of heart tube formation. |
