• BMP9 is a secreted protein and after binding to its receptors, SMAD family transcription factors were recruited and activated, leading to gene expression.
• Homozygous mice expressed the human BMP9 and developed normally.
• This model is useful in studying the role of BMP9 in liver fibrosis.

Strain specific analysis of BMP9 mRNA expression in wild-type C57BL/6N mice and homozygous B-hBMP9 mice by RT-PCR. Liver RNA were isolated from wild-type C57BL/6N mice (+/+) and homozygous B-hBMP9 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human BMP9 primers. Mouse Bmp9 mRNA was detectable only in wild-type C57BL/6N mice. Human BMP9 mRNA was detectable only in homozygous B-hBMP9 mice but not in wild-type mice. 

Western blot analysis of BMP9 protein expression in homozygous B-hBMP9 mice. Plasma and serum were collected from wild-type C57BL/6N mice (+/+) and homozygous B-hBMP9 mice (H/H), (male, 7-week-old, n=2) and then analyzed by western blot with anti-BMP9 antibody (Abcam, ab207318). 20 μg total proteins were loaded for western blotting analysis. The antibody used showed cross-recognition for mouse and human BMP9.