Identification of regulatory sequences and protein-binding sites in the liver-type promoter of a gene encoding 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase.
The liver-type and muscle-type isozymes of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase are encoded by one gene that uses two alternative promoters. We have identified cis-acting sequences and protein-binding sites on the liver-type promoter. Transfection assays with deleted promoters showed that maximal promoter activity is contained within 360 bp upstream of the cap site. DNase I footprinting experiments with liver and spleen nuclear extracts and with purified proteins revealed several protein-binding sites in this region. These included four binding sites for nuclear factor I, one site that contains an octamer consensus but showed a liver-specific footprint pattern, two liver-specific protein-binding sites, and one poly(dG)-containing binding site. Transfection of cells of hepatic origin suggested that all these sites except one are involved in transcriptional regulation. The region between -360 and -2663 contained an element that functioned as a silencer in a nonhepatic cell line. We conclude that in liver transcription from the liver-type promoter of the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene is controlled by ubiquitous and tissue-specific factors and involves activating and derepressing mechanisms.
Lemaigre
F P
FP
Hormone and Metabolic Research Unit, Louvain University Medical School, Brussels, Belgium.
Durviaux
S M
SM
Rousseau
G G
GG
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002872:Chromosome Deletion; D003850:Deoxyribonuclease I; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D025481:Phosphofructokinase-2; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics*; D010770:Phosphotransferases / Q000235:genetics*; D011401:Promoter Regions, Genetic; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014162:Transfection
D009687:Nuclear Proteins; D010770:Phosphotransferases; D025481:Phosphofructokinase-2; D003850:Deoxyribonuclease I; D010744:Phosphoric Monoester Hydrolases