Table 1.

Developmental phenotypes of Id-knockout animal model

Model	Species	Cardiac Phenotype	Reference
Id1 konckdown by siRNA	Chick and mouse	Decreased endocardial epithelial-to-mesenchymal transformation	50
Id2 −/−	Mouse	Atrioventricular septal defects and membranous ventricular septal defects in Id2 null perinatal death, left bundle branch block, indicative of ventricular conduction delay in surviving mice	54, 55
Id4 −/−	Zebrafish	Retrograde blood flow at the atrioventricular canal, indicating defects in atrioventricular valve function	61
Id1 −/− Id3 −/− ; Id1 −/− Id2 −/− ; Id1 −/− Id2 +/− Id3 −/− ; Id1 +/− Id2 +/− Id3 −/−	Mouse	Ventricular septal defects, impaired ventricular trabeculation, thinning of the compact myocardium, and outflow tract atresia at E11.5 to E13.5	46
Id1 −/− Id2 −/− Id3 −/−	Mouse	Reduced heart size by 40 to 60%, defects in auriculoventricular dissociation and thinner ventricular compact layer from E9.5	46
Id1 −/− Id2 −/− Id3 −/− Id4 −/−	Mouse	Heart tube-forming region missed at cardiac crescent stages	45
Id1f/fId3−/− or Id1f/−Id3−/−; Tie2-Cre	Mouse	Fibrotic vasculature, cardiac enlargement, ventricular septal defects and decreased cardiac function	70

E embryonic day, Id inhibitor of DNA binding, siRNA small interfering RNA, Tie2 TEK receptor tyrosine kinase