KIDD BLOOD-GROUP AND UREA TRANSPORT FUNCTION OF HUMAN ERYTHROCYTES ARE CARRIED BY THE SAME PROTEIN

The gene encoding the urea transporter of human erythrocytes (HUT11 cl one) has been cloned recently (Olives, B,, Neau, P,, Bailly, P,, Hedig er, M. A., Rousselet, G,, Cartron, J, P,, and Ripoche, P, (1994) J, Bi ol, Chem, 269, 31649-31652), Now, this gene has been assigned to chrom osome 18q12-q21 by in situ hybridization, as also found for the Kidd ( Jk) blood group locus, In coupled transcription-translation assays, th e HUT11 cDNA directed the synthesis of a 36-kDa protein which was immu noprecipitated by a human anti-Jk(3) antibody produced by immunized Jk (a-b-) donors whose red cells lack Kidd antigens, The anti-Jk(3) antib ody also immunoprecipitated a protein material of 46-60 kDa from all r ed cell membranes, except those from Jk(a-b-) cells, After N-glycanase digestion the 46-60-kDa component was reduced to 36 kDa, A rabbit ant ibody raised against the predicted NH,-terminal amino-acids of the HUT 11 protein reacted on immunoblots with a 46-60-kDa component present i n all human erythrocytes except those from Jk(a-b-) individuals, Jk(a- b-) red cells lack the Kidd/urea transport protein and have a selectiv e defect of the urea transport capacity, but a normal water permeabili ty and aquaporin-associated Colton blood group antigens, These finding s indicate that the erythrocyte urea transporter is encoded by the Kid d locus and may have implications for the biology of urea transporters and their tissue specific regulation.