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Choline acetyltransferase and the vesicular transporter of acetylcholine: A unique gene organization
The Latest in Synaptic Transmission
POSTER
367
3
C H O L I N E A C E T Y L T R A N S F E R A S E AND T H E V E S I C U L A R T R A N S P O R T E R OF A C E T Y L C H O L I N E : A U N I Q U E G E N E O R G A N I Z A T I O N .
Riccardo Cervini, St6phane Bejanin, Jacques Mallet and SIivie Berrard. Laboratoire de G6n6tique Mol6culaire de la Neurotransmission et des Processus Neurod6g6n6ratifs, C.N.R.S., 1 Avenue de la Terrasse, F91198 Gif sur Yvette Cedex, France.
Mammalian choline acetyltransferase (CHAT), the biosynthetic enzyme of acetylcholine, is encoded by multiple mRNAs with different 5' ends. This diversity results from the alternative usage of three promoters and from differential splicing events within the 5' non-coding region. Analysis of the first intron of the rat ChAT gene revealed that it contains an open reading frame which encodes a potential vesicular acetylcholine transporter (rVAT). This transporter is encoded by at least three different mRNAs. Two of them are produced from a ChAT promoter, are generated by alternative splicing and share a common 5'-exon with one ChAT mRNA. The third mRNA species may be synthesized from an additional internal promoter. The ChAT and rVAT gene organization is unique since both coding sequences lie in the same transcriptional orientation and both products are required to express the cholinergic phenotype. This structural organization may not be uncommon and may have implications for the coordinated expression of ChAT and rVAT genes.
POSTER
367
3
C H O L I N E A C E T Y L T R A N S F E R A S E AND T H E V E S I C U L A R T R A N S P O R T E R OF A C E T Y L C H O L I N E : A U N I Q U E G E N E O R G A N I Z A T I O N .
Riccardo Cervini, St6phane Bejanin, Jacques Mallet and SIivie Berrard. Laboratoire de G6n6tique Mol6culaire de la Neurotransmission et des Processus Neurod6g6n6ratifs, C.N.R.S., 1 Avenue de la Terrasse, F91198 Gif sur Yvette Cedex, France.
Mammalian choline acetyltransferase (CHAT), the biosynthetic enzyme of acetylcholine, is encoded by multiple mRNAs with different 5' ends. This diversity results from the alternative usage of three promoters and from differential splicing events within the 5' non-coding region. Analysis of the first intron of the rat ChAT gene revealed that it contains an open reading frame which encodes a potential vesicular acetylcholine transporter (rVAT). This transporter is encoded by at least three different mRNAs. Two of them are produced from a ChAT promoter, are generated by alternative splicing and share a common 5'-exon with one ChAT mRNA. The third mRNA species may be synthesized from an additional internal promoter. The ChAT and rVAT gene organization is unique since both coding sequences lie in the same transcriptional orientation and both products are required to express the cholinergic phenotype. This structural organization may not be uncommon and may have implications for the coordinated expression of ChAT and rVAT genes.