title: Glycophorin A requirement for expression of O-linked antigens on the erythrocyte membrane.
abstract: BACKGROUND
  Glycophorin A (GPA) has a large number of sialic acid-containing oligosaccharide chains. GPA is highly conserved among vertebrates, mice with a GPA deletion have not been reported and GPA's physiologic role remains uncertain.
  
  
  RESULTS
  GPA-/- homozygotes were obtained by intercrossing GPA+/- heterozygotes based on Mendelian genetics. The amount of O-linked oligosaccharide chains in the erythrocyte membrane of GPA-/- mice decreased to 60% compared to that of the wild-type mice. Flow cytometry and Western blot analysis revealed that the TER antigen that is associated with GPA on the erythrocyte membrane was totally abrogated from the cell surface in GPA-/- mice. Several glycoproteins that were detected with peanut agglutinin (PNA), a lectin that recognizes O-linked oligosaccharide chains, were absent from the GPA-/- erythrocyte membrane. Erythrocytes lacking GPA were more sensitive to hypo-osmotic stress than wild-type erythrocyte.
  
  
  CONCLUSIONS
  GPA-/- mice show apparently normal phenotypes at least during the early generations. The disappearance of many glycoproteins recognized by PNA lectin on the GPA-/- erythrocyte membrane proteins suggests that GPA has an essential role in the expression of O-linked antigens on the erythrocyte membrane protein. These interactions of GPA and other glycoproteins may contribute to maintaining the physical strength of the erythrocyte membrane.
authors.affiliation: Department of Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Nagisa
authors.initials: N
authors.lastname: Arimitsu
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Akimitsu
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kotani
authors.forename: Seiichi
authors.initials: S
authors.lastname: Takasaki
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kina
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hamamoto
authors.forename: Koushirou
authors.initials: K
authors.lastname: Kamura
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sekimizu
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006021:Glycophorins / Q000235:genetics / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009844:Oligosaccharides / Q000032:analysis / Q000737:chemistry; D009997:Osmotic Pressure
chemical_list: D000941:Antigens; D006021:Glycophorins; D008562:Membrane Glycoproteins; D009844:Oligosaccharides