CDNA STRUCTURE, TISSUE-SPECIFIC EXPRESSION, AND CHROMOSOMAL LOCALIZATION OF THE MURINE BAND 7.2B GENE

Band 7.2b is an integral phosphoprotein absent from the erythrocyte me mbranes of patients with hydrocytosis, an autosomal, dominantly inheri ted, hemolytic anemia characterized by stomatocytic red blood cells wi th abnormal permeability to Na+ and K+. The role of this protein in th e erythrocyte membrane is not well understood. To gain additional insi ght into the structure and function of this protein, we have cloned th e murine band 7.2b cDNA and studied its tissue-specific expression. 2, 873 bp of cDNA with an open reading frame of 852 bp were isolated. Thi s fragment encodes a protein of 284 amino acids with a predicted molec ular weight of 31 kD. The band 7.2b gene had a wide pattern of express ion, with high levels of mRNA in heart, liver, skeletal muscle, and te stis and low levels in lung, brain, and spleen. Using fluorescent in s itu hybridization, the murine band 7.2b gene was mapped to chromosome 2, at the border of the distal region of 2B and proximal region of C1, syntenic to 9q33-q34, the location of the human homologue. Models of the predicted protein structure showed a short NH2-terminal head, a st rongly hydrophobic 28-amino acid stretch presumably encoding a single membrane-spanning domain, and a large domain composed of beta sheet an d alpha helix. Database searching showed no significant homology of ot her known proteins to murine or human band 7,2b. (C) 1995 by The Ameri can Society of Hematology.