Gene targeting strategy for B-hDLL4 mice. The exons 2-9 of mouse Dll4 gene that encode the extracellular domain were replaced by human DLL4 exons 2-9 in B-hDLL4 mice.

Strain specific analysis of DLL4 gene expression in wild-type (WT) mice and B-hDLL4 mice by RT-PCR. Mouse Dll4 mRNA was detectable only in heart and lung of WT mice (+/+). Human DLL4 mRNA was detectable only in homozygous B-hDLL4 mice (H/H) but not in WT mice (+/+).

Western blot analysis of DLL4 protein expression in homozygous B-hDLL4 mice. Various tissue lysates were collected from wild-type C57BL/6JNifdc (+/+) mice and homozygous B-hDLL4 mice (H/H), and then analyzed by western blot with anti-DLL4 antibody (Abcam, ab176876). 40 μg total proteins were loaded for western blotting analysis. DLL4 were detectable in heart, liver, lung, kidney and cerebellum in wild-type mice and homozygous B-hDLL4 mice. The antibody was cross-reactive between human and mouse. (There is no β-actin in heart)