Figure 3.

The analysis of Lhx9 expression in the control and mutant hearts. (A-B). Lhx9 gene expression is up-regulated in the Fog2 mutant hearts. (A). A comparative real-time PCR analysis of the total (Lhx9α/β) expression in the E11.5 and E13.5 control and Fog2 mutant hearts. (B). A comparative analysis of Lhx9 and Lhx2 gene expression in E13.5 control and Fog2 mutant hearts; Lhx9 expression is examined with α- and β isoform-specific primers. Lhx genes' expression is normalized to the Gapdh gene expression level; the fold changes (y axis) are shown; relative expression in the wild-type sample is normalized to be 1.0. (C-H). Whole-mount staining of the E11.5 (C-D), E12.5 (E-F) and E13.5 (G-H) hearts with an anti-Lhx9α/β RNA probe. Both ventral (C, E, G) and dorsal (D, F, H) views are shown; the wild-type sample is always on the left. In the wild-type E11.5 heart (C-D) ventricles, the atrioventricular groove (arrow) and the outflow tract are weakly positive for Lhx9 expression, while in the Fog2 null heart, Lhx9 expression is strongly enhanced. By E12.5 (E-F) and especially by E13.5 (G-H) Lhx9 expression appears almost extinguished in the control heart, while the Fog2 mutant sample remains strongly positive for Lhx9 expression. The scale bar is 200 μM.