The MJ7/18 monoclonal antibody specifically binds to mouse CD105 (also known as endoglin) which is a homodimer of 90-kDa subunits and is predominantly expressed on vascular endothelial cells. High levels of mouse endoglin mRNA have been reported to be detectable in the ovary, uterus, NCTC-2071 fibroblasts, and to a lesser extent, in heart, muscle and stromal cells in connective tissue of various organs. Endoglin has been reported to play an essential role in embryonic angiogenesis. Both mouse and human endoglin display strong amino-acid sequence homology to the transmembrane and cytoplasmic regions of the type III TGF-ß receptor.