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Novel form of L‐aromatic amino acid decarboxylase mRNA in rat antral mucosa
Author(s) -
Djali PK,
Dimaline R,
Dockray GJ
Publication year - 1998
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1998.sp004143
Subject(s) - antrum , aromatic l amino acid decarboxylase , messenger rna , chemistry , biochemistry , medicine , microbiology and biotechnology , biology , enzyme , stomach , gene
Gut endocrine cells possess the capacity to take up and decarboxylate biogenic amine precursors. Decarboxylation is mediated by aromatic L‐amino acid decarboxylase (AADC) which is encoded by mRNAs differing in their 5' untranslated regions (UTR) depending on the usage of alternative first exons, 1a and 1b, each with its own acceptor site (−13 and −8 bases relative to the translation start site, respectively). We describe here a novel splice variant of exon 1a‐AADC mRNA in rat antral mucosa. Both exon 1a and 1b mRNAs were expressed in rat antral mucosa, but the 1a form was spliced into the acceptor site usually associated with exon 1b (−8). An enteroendocrine cell line (STC‐1) expressed exon 1a or exon 1b mRNAs spliced into the ‐8 acceptor site of exon 2. Transient transfection of a range of cell lines with reporter constructs revealed that all three 5' UTRs efficiently supported expression of the Luciferase reporter. There is therefore a novel, functional 57' UTR of AADC mRNA in rat antral mucosa; alternative AADC splice variants could provide the capacity for control at the level of mRNA translation.