Gene targeting strategy for B-hRSPO1 mice. The exons 4-6 of mouse Rspo1 gene that encode the full-length protein were replaced by human RSPO1 exons 5-7 in B-hRSPO1 mice.

Strain specific analysis of RSPO1 gene expression in wild-type C57BL/6 mice and B-hRSPO1 mice by RT-PCR. Mouse Rspo1 mRNA was detectable in kidney of wild-type C57BL/6 mice (+/+). Human RSPO1 mRNA was detectable only in homozygous B-hRSPO1 mice (H/H) but not in wild-type C57BL/6 mice.

Strain specific analysis of RSPO1 expression in wild-type C57BL/6 mice and B-hRSPO1 mice by western blot. Liver tissue was collected from wild-type C57BL/6 mice (+/+) and homozygous B-hRSPO1 mice (H/H), and then analyzed by western blot with anti-RSPO1 antibody. RSPO1 was detectable in the liver of B-hRSPO1 mice and wild-type mice, as the antibody is cross-recognize both human and mouse RSPO1.