Expression of cytoskeletal protein 4.1 during avian erythroid cellular maturation.

We have isolated a cDNA clone encoding part of protein 4.1, an integral component of the erythrocyte cytoskeleton. The recombinant was isolated by immunological screening of a chicken erythroid lambda gt11 cDNA library using a monoclonal antibody directed against protein 4.1. DNA blot analysis shows that the gene is present as a single copy per haploid chicken genome, while RNA blot analysis reveals the presence of a single mRNA of 7 kilobases in reticulocytes. Message of the same size (in reduced amounts) is also present in an erythroleukemic cell line transformed by avian erythroblastosis virus and is also present in vastly reduced quantities in nonerythroid hemopoietic cells. Immunoblotting and immunofluorescence experiments show that a subset of the chicken 4.1 variant proteins is preferentially expressed during in vitro differentiation of chicken erythroleukemic cells. These data indicate that the gene is both actively transcribed and translated during early erythroid cellular maturation.