A unique gene organization for two cholinergic markers, choline acetyltransferase and a putative vesicular transporter of acetylcholine.
Choline acetyltransferase (ChAT) is the biosynthetic enzyme of acetylcholine. In mammalian tissues, it is encoded by multiple mRNAs with different 5'-ends. This diversity results from the alternative usage of three promoters and from differential splicing events. Here, we show that the first intron of the rat ChAT gene contains an open reading frame that encodes a potential vesicular acetylcholine transporter based on the following criteria. (i) The encoded protein is structurally similar to transporter proteins, the highest identity being found with the vesicular acetylcholine transporters from Torpedo and Caenorhabditis elegans (77 and 56%, respectively, in 352 amino acids). (ii) The corresponding mRNAs exhibit a cholinergic expression profile. Amplification experiments with spinal cord cDNA revealed that at least three mRNAs encode this transporter. Two contain the same 5' non-coding region as two ChAT mRNAs and, therefore, are derived from the ChAT transcription unit by alternative splicing. The third mRNA may be transcribed from an additional internal promoter.
Bejanin
S
S
Laboratoire de Génétique Moléculaire de la Neurotransmission et des Processus Neurodégénératifs, CNRS, Gif sur Yvette, France.
Cervini
R
R
Mallet
J
J
Berrard
S
S
D000109:Acetylcholine / Q000378:metabolism*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D002795:Choline O-Acetyltransferase / Q000235:genetics*; D006801:Humans; D007438:Introns; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013572:Synaptic Vesicles / Q000378:metabolism*; D014158:Transcription, Genetic; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; C493459:SLC18A3 protein, human; C493461:Slc18a3 protein, rat; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine