Abstract
Background: Glycophorin A (GPA) has a large number of sialic acidโcontaining 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^โ/โ^ homozygotes were obtained by intercrossing GPA^+/โ^ heterozygotes based on Mendelian genetics. The amount of Oโlinked oligosaccharide chains in the erythrocyte membrane of GPA^โ/โ^ mice decreased to 60% compared to that of the wildโtype 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^โ/โ^ mice. Several glycoproteins that were detected with peanut agglutinin (PNA), a lectin that recognizes Oโlinked oligosaccharide chains, were absent from the GPA^โ/โ^ erythrocyte membrane. Erythrocytes lacking GPA were more sensitive to hypoโosmotic stress than wildโtype erythrocyte.
Conclusions: GPA^โ/โ^ mice show apparently normal phenotypes at least during the early generations. The disappearance of many glycoproteins recognized by PNA lectin on the GPA^โ/โ^ erythrocyte membrane proteins suggests that GPA has an essential role in the expression of Oโlinked antigens on the erythrocyte membrane protein. These interactions of GPA and other glycoproteins may contribute to maintaining the physical strength of the erythrocyte membrane.