Figure 2.

Neonatal mice with smooth muscle-specific Jag-1 gene deletion exhibit patent ductus arteriosus. A conditional, Cre-responsive Jag-1 allele was crossed to the SM22α-Cre strain (TagIn-Cre) as described (Feng et al., 2010). To visualize the outflow tract and ductus arteriosus, the left ventricles of control littermate (A) and Jag-1 smooth muscle deletion (B) neonatal mice were injected with silicone rubber injection compound (tinted yellow). While the ductus arteriosus closed normally in the control mouse, it remained patent (open) in the Jag-1 smooth muscle deletion mouse. Associated defects in VSMC differentiation were also observed. DA, ductus arteriosus; LC, left carotid artery; LSC, left subclavian artery; RC, right carotid artery; RSC, right subclavian artery.