Origin and transcriptional control of the cardiac conduction system

The cardiac conduction system orchestrates the heartbeat and malfunction of its components is becoming more prevalent and can give rise to serious problems. To understand the underlying causes, further insights into the molecular mechanisms of cardiac conduction system development and function are needed. In this thesis, we 1) identified T-box transcription factor 3 (Tbx3)-positive embryonic cardiomyocytes to constitute the progenitor population of the mature cardiac conduction system, 2) interrogated the role of transcription factor Tbx3 in atrioventricular conduction system development and function, and 3) characterized several regulatory DNA elements that are regulated by Tbx3 and together control transcription of ion channel-encoding genes Scn5a (Nav_1.5), Ryr2 (Ryanodine receptor 2), and Cacna1g (Cav_3.1).