Characterization of seven low incidence blood group antigens carried by erythrocyte band 3 protein

Recent studies have demonstrated that band 3 carries antigens of the Diego blood group system and have elucidated the molecular basis of several previ ously unassigned low incidence and high incidence antigens. Because the ava ilable serological data suggested that band 3 may carry additional low inci dence blood group antigens, we screened band 3 genomic DNA encoding the mem brane domain of band 3 for single-strand conformational polymorphisms. We f ound that the putative first ectoplasmic loop of band 3 carries blood group antigen ELO, 432 Arg-->Trp; the third putative loop harbors antigens Vg(a) (Van Vugt), 555 Tyr-->His, BOW 561 Pro-->Ser, Wu (Wulfsberg), 565 Gly-->Al a, and Bp(a) (Bishop), 569 Asn-->Lys; and the putative fourth ectoplasmic l oop carries antigens Hg-a (Hughes), 656 Arg-->Cys, and Mo-a (Moen), 656 Arg -->His. We studied erythrocytes from carriers of five of these blood group antigens. We found similar levels of reticulocyte mRNA corresponding to the two band 3 gene alleles, normal content and glycosylation of band 3 in the red blood cell membrane, and normal band 3-mediated sulfate influx into re d blood cells, suggesting that the mutations do not have major effect on ba nd 3 structure and function. In addition to elucidating the molecular basis of seven low incidence blood group antigens, these results help to create a more accurate structural model of band 3. (C) 1998 by The American Societ y of Hematology.