Variant AE2 anion exchanger transcripts accumulate in multiple cell types in the chicken gastric epithelium

Molecular analyses have resulted in the isolation of two chicken stomach AE2 anion exchanger cDNAs, AE2-1 and AE2-2, The similar to 4.3-kilobase (kb) AE2-1 cDNA contains an open reading frame that encodes a predicted polypeptide of similar to 135 kDa that is homologous to AE2 anion exchangers from other species, The partial similar to 1.7-kb AE2-2 cDNA, which differs from the AE2-1 cDNA in two regions, would be predicted to encode an AE2 polypeptide with an alternative N-terminal cytoplasmic tail. Examination of the distribution of these variant transcripts has revealed that AE2 transcripts ranging in size from similar to 4.4 to similar to 7.3 kb accumulate in various adult tissues. However, in the stomach, the unique sequence at the 5'-end of AE2-1 is preferentially associated with transcripts that range in size from similar to 4.5 to similar to 4.9 kb, while the unique sequence at the 5'-end of AE2-2 is preferentially associated with the similar to 7.3-kb AE2 RNA species, lit situ hybridization analyses have further revealed that AE2 transcripts accumulate to very high levels within the acid-secreting epithelial cells of the profound gland in the stomach and, to a lesser extent, within the mucus-secreting cells of the superficial gland that line the stomach lumen, This result suggests that AE2 anion exchangers are involved in the regulation of intracellular pH in each of these gastric epithelial cell types.