Functional characterization of the rat gamma-glutamyl transpeptidase promoter that is expressed in transformed rat liver epithelial cells.
In the rat the gamma-glutamyl transpeptidase (GGT) gene codes for at least four different messenger RNAs (mRNA I to mRNA IV) which differ only in their 5' untranslated regions and are transcribed from a single copy gene in a tissue-specific manner. In the liver GGT expression is up-regulated in transformed cells. To understand the induction mechanisms of GGT activity by transformation, we previously cloned the 5' region of the rat GGT gene which contains the 5' untranslated leader sequence for mRNA I. In the present study, using transfection and reporter gene assays, I have demonstrated that (1) the sequence from positions -369 to +226 drives a relatively strong promoter activity in C5 and AKG cell lines, transformed rat liver epithelial cells, but a very weak one in RLE-228 cells, a normal rat liver epithelial cell line; and (2) removal of the region between -418 and -369 increases CAT activity more than 10-fold in RLE-228, C5 and AKG cells, and the DNA fragment spanning nucleotides -761 to -292 significantly reduces CAT activity driven by the adenine phosphoribosyl transferase (APRT) promoter in RLE-228 cells.
Park
J H
JH
Department of Biology, Changwon National University, Korea. parkjh@sarim.changwon.ac.kr
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D005809:Genes, Regulator / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D022781:Hepatocytes / Q000378:metabolism*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D017384:Sequence Deletion; D005723:gamma-Glutamyltransferase / Q000235:genetics* / Q000378:metabolism
D015500:Chloramphenicol O-Acetyltransferase; D005723:gamma-Glutamyltransferase