Figure 7.

Model for Tbx1 dosage dependent regulation of AHF genes important for OFT septation. In the model, we compare the Tbx1 mutant (left) to control embryos at E9.5. The upper left triangle represents the Tbx1 expression pattern in the AHF that will migrate into the cardiac OFT. Left panel: depicts how altered dosage of Tbx1 results in imbalanced AHF gene expression, which causes a PTA. Right panel: Tbx1 dosage in the AHF of a control embryo. We show that Tbx1 is a key regulator of gene expression for normal cardiac OFT formation resulting in a normal aorta and pulmonary trunk.