Characterization of the mouse Rh blood group gene

The Rh blood group system is of clinical importance in blood transfusion an d as the cause of hemolytic disease of the newborn. Other than their role a s carriers of Rh antigens, very little is known about the function of the R h polypeptides. As a first step to generate an animal model system in which to study the structure and function of Rh, and to extend the phylogenetic analysis of RH genes, the Rh homologue from Mus musculus was characterized. Comparison of RH from humans and mice revealed 71 and 58% sequence identit y at the nucleotide and amino acid levels, respectively. Mouse Rh mRNA enco des a protein which is 1 amino acid longer (418 aa) than that of human (417 aa). Rh protein was detected in mouse erythrocyte membranes and was compar able in size to human Rh. Mouse erythrocytes do not show serologic reactivi ty with human Rh antibodies, probably because the greatest divergence betwe en the mouse and the human genes was seen in the predicted extracellular lo ops, while the transmembrane regions were more conserved. The mouse RH locu s consists of only one gene, which is important for future genetic manipula tion and which also indicates that the RH gene duplication seen in humans h as occurred since the mammalian radiation. (C) 1999 Academic Press.