Structure and Organization of the Murine Band 3 Gene

The Band 3 protein mediates the reversible exchange of chloride and bicarbonate anions across the plasma membrane of erythrocytes, and probably, certain epithelial cells. It also serves to anchor the spectrin cytoskeleton to the plasma membrane via its association with ankyrin. We have isolated and largely sequenced the 17-kilobase murine Band 3 gene. We show that this gene is present in a single copy in the mouse genome and have identified and mapped the 19 intervening sequences. The locations of the intron/exon junctions in the Band 3 mRNA correlate with predicted structural features of the erythrocyte Band 3 protein structure and membrane topology. One of the introns within this gene contains a single copy of a murine Alu-type high dispersed sequence, in addition to several unusual tandemly repeated sequences.