Differential cholecystokinin brain/gut transcription initiation in the rat: evidence for brain-specific start sites.
Brain/gut cholecystokinin (CCK) has well-established translational and post-translational differences. By contrast, CCK transcription regulation is reported to be the same in brain and gut. Accordingly, the rat CCK gene has been evaluated for differential brain/gut transcription initiation. Using the 5'-flanking region of the rat CCK gene, DNase I protection assays were performed. We evaluated reporter constructs deleted of the conventional transcription start site in cell culture. Finally, brain and gut mRNA was evaluated using both a reverse transcription serial primer polymerase chain reaction assay as well as rapid amplification of cDNA ends (RACE) analysis. TFIID protein protects against DNase I digestion between -177 and -196 bp. In tissue culture, spontaneous 5'-flanking region transcription initiation occurs until deletion proceeds upstream of -140 bp. RACE analysis performed on mRNA from the rat brain identifies heretofore undescribed transcription initiation at -43 bp 5' as well as at +1,212 (in exon II). These alternative transcription initiation sites are utilized in brain, but not gut. The rat CCK gene has alternative 5'-flanking region transcription initiation sites. These alternative sites are utilized only in the brain. These data may provide insights into how brain and gut respond to their differing physiological demands.
Katsel
P L
PL
Laboratory of Molecular Surgical Research, VAMC Bronx, NY 10468, USA.
Greenstein
R J
RJ
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002766:Cholecystokinin / Q000096:biosynthesis* / Q000235:genetics; D003001:Cloning, Molecular; D017930:Genes, Reporter; D007421:Intestine, Small / Q000378:metabolism*; D008156:Luciferases / Q000096:biosynthesis; D016297:Mutagenesis, Site-Directed; D009928:Organ Specificity; D010911:Pituitary Neoplasms; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
D011993:Recombinant Fusion Proteins; D002766:Cholecystokinin; D008156:Luciferases