Cooperative and antagonistic roles for Irx3 and Irx5 in cardiac morphogenesis and postnatal physiology. Mus musculus

Analysis of the roles of Irx3 and Irx5 transcription factors in mouse heart development and postnatal heart function. Results show that show that Irx3 and Irx5 have redundant function in the in the endocardium to regulate atrioventricular canal morphogenesis and outflow tract formation. A postnatal deletion of Irx3 and Irx5 surprisingly results in a restoration of the repolarization gradient that is altered in Irx5 mutant hearts, suggesting a model whereby postnatal Irx3 activity is normally repressed by Irx5. Overall design: 4 genotypes were analyzed: Irx5+/- (3 samples), Irx3-/-;Irx5+/- (4 samples), Irx5-/- (3 samples), Irx5-/-;Irx3-/- (4 samples). The Irx5+/- samples are the reference.