Anion transporter: highly cell-type-specific expression of distinct polypeptides and transcripts in erythroid and nonerythroid cells
Affinity-purified antibodies and cDNA probes specific for the chicken erythrocyte anion transporter (also referred to as band 3) have been used to demonstrate that this protein is expressed in a highly cell- type-specific manner in the avian kidney. Indirect immunofluorescence analysis indicates that this polypeptide is present in only a small subset of total kidney cells and is predominantly localized to the proximal convoluted tubule of this organ. Chicken erythrocytes synthesize and accumulate two structurally and serologically related band 3 polypeptides. The polypeptide that accumulates in kidney membranes has an apparent molecular weight greater than either of its erythroid counterparts. This diversity is also reflected at the RNA level, as the single band 3 mRNA species detected during various stages of erythroid development is distinct in size from that found in kidney cells. Genomic DNA blot analysis suggests that both the erythroid and kidney band 3 RNAs arise from a single gene. Furthermore, of the adult tissues we have examined that are known to express ankyrin and spectrin polypeptides, only kidney accumulates detectable levels of the band 3 mRNA and polypeptide. These observations suggest that a subset of kidney cells use an anion transport mechanism analogous to that of erythrocytes and that band 3 is expressed in a noncoordinate manner with other components of the erythroid membrane skeleton in nonerythroid cells.
Additional Information© 1985 by The Rockefeller University Press. RUP grants the public the non-exclusive right to copy, distribute, or display the Work under a Creative Commons Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ and http://creativecommons.org/licenses/by-nc-sa/3.0/legalcode. Received for publication 30 January 1985, and in revised form 15 February 1985. We thank Dr. W. James Nelson for providing the purified avian erythrocyte band 3 protein used for peptide mapping, and Dr. J. Robinson and Dr. Nelson for their advice regarding two-dimensional peptide mapping. We appreciate helpful discussions with Dr. B. Wold, Dr. Y. Capetanaki, and J. Ngai during the course of this work, and we are grateful to Dr. Y. Capetanaki and J. Ngai for their comments on the manuscript. Ilga Lielausis and Adriana Cortenbach provided expert technical assistance. This work was supported by grants from the National Institutes of Health, the National Sciences Foundation, and the Muscular Dystrophy Association of America. J.V. Cox was supported by a postdoctoral fellowship from the Muscular Dystrophy Association of America, and R.T. Moon by a postdoctoral fellowship from the American Cancer Society and a grant from the Procter and Gamble Company to the Division of Biology. E. Lazarides was the recipient of a Research Career Development Award.
Published - COXjcb85.pdf