Alternative splicing leads to two cholinergic proteins in Caenorhabditis elegans.
The cha-1 gene of Caenorhabditis elegans encodes choline acetyl-transferase (the acetylcholine synthetic enzyme). The C. elegans unc-17 gene encodes a synaptic vesicle-associated acetylcholine transporter. The two genes thus define sequential biochemical steps in the metabolism of the neurotransmitter acetylcholine. Cloning, sequencing, and molecular analysis of the unc-17 region indicate that cha-1 and unc-17 transcripts share a 5' untranslated exon, and the rest of the unc-17 transcript is nested within the long first intron of cha-1. Thus, two proteins with related functions but with no sequences in common are produced as a result of alternative splicing of a common mRNA precursor. The structure of this transcription unit suggests a novel type of coordinate gene expression, and a temporal processing model is proposed for the regulation of cha-1 and unc-17 expression.
Alfonso
A
A
Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City 73104.
Grundahl
K
K
McManus
J R
JR
Asbury
J M
JM
Rand
J B
JB
D000483:Alleles; D017398:Alternative Splicing; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins / Q000235:genetics*; D002795:Choline O-Acetyltransferase / Q000235:genetics*; D005091:Exons; D015801:Helminth Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D015183:Restriction Mapping; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D015801:Helminth Proteins; C082365:Unc-17 protein, C elegans; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins; D002795:Choline O-Acetyltransferase