CLONING OF GLYCOPROTEIN-D CDNA, WHICH ENCODES THE MAJOR SUBUNIT OF THE DUFFY BLOOD-GROUP SYSTEM AND THE RECEPTOR FOR THE PLASMODIUM-VIVAX MALARIA PARASITE

cDNA clones encoding the major subunit of the Duffy blood group were i solated from a human bone marrow cDNA library using a PCR-amplified DN A fragment encoding an internal peptide sequence of glycoprotein D (gp D) protein. The open reading frame of the 1267-bp cDNA clone indicated that gpD protein was composed of 338 amino acids, predicting a M(r) o f 35,733, which was the same as a deglycosylated gpD protein. Portions of the predicted amino acid sequence, matched with six CNBr/pepsin pe ptides obtained from affinity-purified gpD protein. In ELISA analysis, an anti-Duffy murine monoclonal antibody reacted with a synthetic pep tide deduced from the cDNA clone. Hydropathy analysis suggested the pr esence of 9 membrane-spanning alpha-helices. In bone marrow RNA blot a nalysis, the gpD cDNA detected a 1.27-kb mRNA in Duffy-positive but no t in Duffy-negative individuals. It also identified the same size mRNA in adult kidney, adult spleen, and fetal liver; in brain, it detected a prominent 8.5-kb and a minor 2.2-kb mRNA. In Southern blot analysis , gpD cDNA identified a single gene in Duffy-positive and -negative in dividuals. Duffy-negative individuals, therefore, have the gpD gene, b ut it is not expressed in bone marrow. The same or a similar gene is a ctive in adult kidney, adult spleen, and fetal liver of Duffy-positive individuals. Whether this is true in Duffy-negative individuals remai ns to be demonstrated. A GenBank sequence search yielded a significant protein sequence homology to human and rabbit interleukin-8 receptors .