Expression of the
erythrocyte anion exchanger band 3, and
ankyrin and
spectrin, two
cytoskeletal proteins of the red blood cell membrane, was studied by immunofluorescence using: 1) smears of human bone marrow from healthy donors and from a patient with
erythroleukemia, 2) human red blood cell precursors grown in cell culture, and 3) murine
erythroleukemia cells grown in cell culture. Double immunostaining with
antibodies to band 3 in combination with
spectrin or
ankyrin revealed that these
proteins become expressed synchronously during normal human erythropoiesis. In contrast, both murine
erythroleukemia cells (induced by
fibronectin and
dimethyl sulfoxide to differentiate in vitro) and erythroblasts from a patient suffering from
erythroleukemia displayed distinct asynchronicity in expression of these
proteins, ie,
ankyrin and
spectrin were synthesized first, followed by band 3 at a later stage of erythroid development. After the onset of band 3 expression in human
erythroleukemia cells, an increase of membrane-associated fluorescence was detectable for both
ankyrin and
spectrin, supporting the general view that band 3 promotes assembly of the membrane cytoskeleton. These findings indicate that the current concept of a sequential expression of
spectrin/
ankyrin and band 3 is valid only for
erythroleukemia cells or transformed erythropoietic cell lines but does not occur in normal erythropoiesis, during which these
proteins become expressed simultaneously.