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. Author manuscript; available in PMC: 2011 Oct 1.
Published in final edited form as: Pediatr Res. 2010 Oct;68(4):275–280. doi: 10.1203/PDR.0b013e3181ee0028

Figure 3.

Figure 3

SA node patterning is abnormal in e11.5 Zic3 null embryos. A-C. Molecular characterization in a wild type embryo. In (A) Hcn4 expression delineates the SA node, positioned above the right atrium. B. High power view of SA node visualized in (A), demonstrating Hcn4 staining of a wedge shaped area of tissue. Nkx2.5 is excluded from this region (arrow) but is expressed in the surrounding myocardium in (C). D-F. Zic3 null embryo with abnormal anterior-posterior positioning of the ventricles and misalignment of the atria. The abnormally elongated SA node region is indicated by presence of Hcn4 staining (D, E, arrow) and lack of Nkx2.5 staining (F). G-I. Zic3 null embryo with dextrocardia and common ventricle. Strong bilateral Hcn4 staining was observed above the atria (G, H), and Nkx2.5 staining was absent (I). Scale bars in A, D, G are 0.5 mm. Scale bars in B, C, E, F, H, I are 100 μm.