• EFEMP1 encodes EGF-containing fibulin-like extracellular matrix protein 1, an extracellular glycoprotein expressed in the basement membrane of epithelial and endothelial cells, and is expressed in various tissues throughout the body, including the retina.
• The exons 1-11 of mouse Efemp1 gene that encode the whole molecule, including promoter, 5’UTR and 3’UTR were replaced by human counterparts in B-hEFEMP1 mice. The human EFEMP1 expression was driven by human EFEMP1 promoter, while mouse Efemp1 gene transcription and translation will be disrupted.
• Human EFEMP1 was detected in eyeball, uterus, skin and lung of B-hEFEMP1 mice but not wild-type C57BL/6 mice.
• Human EFEMP1 mRNA was exclusively detectable in homozygous B-hEFEMP1 mice but not in wild-type mice.

Gene targeting strategy for B-hefemp1 mice. The exons 1-11 of mouse Efemp1 gene that encode the whole molecule, including promoter, 5’UTR and 3’UTR were replaced by human counterparts in B-hEFEMP1 mice. The human EFEMP1 expression was driven by human EFEMP1 promoter, while mouse Efemp1 gene transcription and translation will be disrupted.

Strain specific analysis of EFEMP1 mRNA expression in wild-type C57BL/6 mice and B-hEFEMP1 mice by RT-PCR. Skin RNA were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hEFEMP1 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human EFEMP1 primers. Mouse Efemp1 mRNA was only detectable in wild-type mice. Human EFEMP1 mRNA was exclusively detectable in homozygous B-hEFEMP1 mice but not in wild-type mice.

Western blot analysis of EFEMP1 protein expression in homozygous B-hEFEMP1 mice. Various tissue lysates were collected from wild-type C57BL/6 mice (+/+) (Male, 6-week-old, n=1) and homozygous B-hEFEMP1 mice (H/H) (Male, 6-week-old, n=1), and then analyzed by western blot with anti-human EFEMP1 antibody (abcam, ab256457). 40 μg total proteins were loaded for western blotting analysis. Human EFEMP1 was detected in eyeball, uterus, skin and lung of B-hEFEMP1 mice but not wild-type C57BL/6 mice.