Generation of truncated brain AE3 isoforms by alternate mRNA processing.
AE3 gene is a member of the AE anion exchanger gene family that is expressed primarily in brain and heart. The principal product of the AE3 gene in rodent brain, FL-AE3p, when expressed in heterologous cell lines, gives rise to chloride-dependent changes in intracellular pH consistent with its operation as an anion exchanger. We have identified two novel isoforms of mouse AE3 that are generated by tissue-specific alternate RNA processing. One of these isoforms encodes a polypeptide, 14-AE3p, that corresponds to a portion of the NH2-terminal cytoplasmic domain of AE3. 14-AE3p lacks the entire transmembrane domain that-in FL-AE3p forms the anion exchange channel. Immunoblots with antibodies to the NH2- and COOH-termini confirm that FL-AE3 and 14-AE3 are expressed in rat brain as 160 kDa and 74 kDa polypeptides, respectively. Unlike FL-AE3p, however, 14-AE3p is insoluble in non-ionic detergent, suggesting a possible association with the cytoskeleton.
Morgans
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CW
Department of Biological Sciences, Stanford University, CA 94305-5020.
Kopito
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RR
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D017920:Antiporters; D001483:Base Sequence; D001923:Brain Chemistry; D003001:Cloning, Molecular; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000096:biosynthesis; D017421:Sequence Analysis; D012995:Solubility; D014018:Tissue Distribution; D014162:Transfection
D017920:Antiporters; D008565:Membrane Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; C062002:Slc4a3 protein, mouse; C489238:Slc4a3 protein, rat