Gene targeting strategy for B-hDLL1 mice. The mouse Dll1 gene that encode the extracellular domain were replaced by human DLL1 counterpart gene in B-hDLL1 mice.

Strain specific analysis of DLL1 gene expression in wild-type mice and B-hDLL1 mice by RT-PCR. Mouse Dll1 mRNA was detectable in spleen of wild-type mice (+/+). Human DLL1 mRNA was detectable only in homozygous B-hDLL1 mice (H/H) but not in wild-type mice. Strain specific DLL1 expression analysis in homozygous B-hDLL1 mice by western blot. Heart tissue, spleen tissue and lung tissue were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hDLL1 mice (H/H), and analyzed by western blot with anti-hDLL1 antibody. Human DLL1 was detectable in wild-type mice and homozygous B-hDLL1 mice, as the antibody is crossly reactive with DLL1 in human and mice.