Gene targeting strategy for B-hUPA mice. The full coding region of mouse Upa was replaced by human UPA coding region in B-hUPA mice.

Strain specific analysis of UPA gene expression in wild-type mice and B-hUPA mice by RT-PCR and western blot. (A) Mouse Upa mRNA was detectable in kidney of wild-type mice (+/+). Human UPA mRNA was detectable only in homozygous B-hUPA mice (H/H) but not in wild-type mice. (B) Liver and kidney tissues were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hUPA mice (H/H), and analyzed by western blot with anti-UPA antibody. UPA was detectable in wild-type C57BL/6 mice (+/+) and homozygous B-hUPA mice (H/H), as evidenced by cross-reactivity of antibody against mouse and human UPA proteins.