ZFIN Image: Gauvrit et al., 2022, Figure 2

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Figure Caption

Figure 2 Overview of molecular pathways in the mammalian cardiac conduction system. The sinoatrial node (SAN, green) develops from Tbx18⁺, Nkx2-5^low progenitor cells. Nkx2-5 represses expression of Tbx3 and Isl1 to establish the boundary between the SAN and atrial cardiomyocytes. SAN precursor cell differentiation is marked by expression of Tbx3, Isl1, Shox2, and Hcn4. Pitx2 represses SAN development on the left side of the sinus venosus by repressing this transcriptional network. The Tbx5 (activator) and Pitx2 (repressor) regulatory loop regulates atrial conduction genes. Relative Tbx3/Tbx5 dosage determines specification of the conduction system. The atrioventricular node (AVN, blue) acts as a secondary pacemaker, and is characterized by slow conduction that is patterned by low levels of Tbx5 and high levels of Tbx3. A fast conduction state in the ventricular conduction system (VCS, pink) is specified by higher levels of Tbx5 and low Tbx3.

Acknowledgments

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