Cloning of the multipartite promoter of the sodium-calcium exchanger gene NCX1 and characterization of its activity in vascular smooth muscle cells.
The sodium-calcium exchange activity is mediated by proteins encoded in a small gene family, of which the gene NCX1 is ubiquitously expressed in mammalian tissues. In this study, the multipartite promoter of this gene was analyzed in the human and rat genomes by means of DNA cloning, reverse transcriptase-polymerase chain reaction, and transient transfection of fusion constructs with the firefly luciferase gene into cultured rat aortic smooth muscle cells. The gene-proximal promoter, located 30 kilobase pairs (kb) away from the first coding exon 2, has features of a GC-rich housekeeping promoter and is apparently always active; in specific tissues, however, it is augmented by one or two additional promoters, located either within 1.5 kb upstream of it, or 35 kb upstream. The gene proximal promoter shows the highest activity in aortic smooth muscle cells. In mammalian species transcripts from all three promoters undergo splicing via an intermediate, containing two noncoding exons, of which the downstream one is normally not present in the terminal splicing product.
Scheller
T
T
Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8092 Zürich, Switzerland.
Kraev
A
A
Skinner
S
S
Carafoli
E
E
D017398:Alternative Splicing; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D005091:Exons; D017930:Genes, Reporter; D006801:Humans; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D053499:Plasma Membrane Calcium-Transporting ATPases; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D016415:Sequence Alignment; D019831:Sodium-Calcium Exchanger / Q000235:genetics* / Q000378:metabolism
D027682:Cation Transport Proteins; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D053499:Plasma Membrane Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases