The organization of the gene (EPB72) encoding the human erythrocyte band 7 integral membrane protein (protein 7.2b).

The human gene EPB72 coding for the band 7 integral membrane protein, a major protein of the erythrocyte membrane, was isolated from a genomic DNA library and characterized. Spanning approximately 30 kb, the human EPB72 gene comprises seven exons ranging from 73 to 2331 bp; intron sizes range from 970 to approximately 11,200 bp. The first exon contains the 5'-untranslated region (61 nucleotides) and the coding sequence for the N-terminal domain; the second exon encodes the hydrophobic domain, including flanking cysteine and lysine residues. Exon 7 contains the C-terminal portion and a 2-kb 3'-untranslated region. The potential promoter region contains several consensus sequences for ubiquitous transcription factors (Sp1, AP1, AP2, CP1/2, NF kappa B, CREB, Ets-1, and CACC/GT-BF) and two imperfect sequences for erythroid factors (EKLF and GATA-1), in accordance with the ubiquitous distribution of the EPB72 mRNA in different cell types. No TATA box was apparent. An inverted Alu repeat element, flanked by nonamer direct repeats, was identified within the region -913/-620, relative to the cap site. Six additional Alu repeat elements, including one monomer and one trimer, were identified within the introns and the 3'-untranslated region. Two polyadenylation signals in the 3'-noncoding region of exon 7 enable the production of two mRNA species.