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Chicken ovalbumin upstream promoter-transcription factor II, a new partner of the glucose response element of the L-type pyruvate kinase gene, acts as an inhibitor of the glucose response.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 1999 Oct 01; Vol. 274 (40), pp. 28385-94. - Publication Year :
- 1999
-
Abstract
- Transcription of the L-type pyruvate kinase (L-PK) gene is induced by glucose in the presence of insulin and repressed by glucagon via cyclic AMP. The DNA regulatory sequence responsible for mediating glucose and cyclic AMP responses, called glucose response element (GlRE), consists of two degenerated E boxes spaced by 5 base pairs and is able to bind basic helix-loop-helix/leucine zipper proteins, in particular the upstream stimulatory factors (USFs). From ex vivo and in vivo experiments, it appears that USFs are required for correct response of the L-PK gene to glucose, but their expression and binding activity are not known to be regulated by glucose. A genetic screen in yeast has allowed us to identify a novel transcriptional factor binding to the GlRE, i.e. the chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII). Binding of COUP-TFII to the GlRE was confirmed by electrophoretic mobility shift assays, and COUP-TFII-containing complexes were detectable in liver nuclear extracts. Neither abundance nor binding activity of COUP-TFII appeared to be significantly regulated by diets. In footprinting experiments, two COUP-TFII-binding sites overlapping the E boxes were detected. Overexpression of COUP-TFII abrogated the USF-dependent transactivation of an artificial GlRE-dependent promoter in COS cells and the glucose responsiveness of the L-PK promoter in hepatocytes in primary culture. In addition, a mutated GlRE with increased affinity for USF and very low affinity for COUP-TFII conferred a dramatically decreased glucose responsiveness on the L-PK promoter in hepatocytes in primary culture by increasing activity of the reporter gene in low glucose condition. We propose that COUP-TFII could be a negative regulatory component of the glucose sensor complex assembled on the GlRE of the L-PK gene and most likely of other glucose-responsive genes as well.
- Subjects :
- Animals
Base Sequence
COS Cells
COUP Transcription Factor II
COUP Transcription Factors
Cell Nucleus metabolism
Chickens
Cloning, Molecular
DNA Primers
DNA-Binding Proteins genetics
Diet
Glucose antagonists & inhibitors
Liver metabolism
Mice
Promoter Regions, Genetic
Protein Binding
Rats
Repressor Proteins genetics
Repressor Proteins metabolism
Saccharomyces cerevisiae genetics
Transcription Factors genetics
Transcription, Genetic
Upstream Stimulatory Factors
DNA-Binding Proteins metabolism
Glucose metabolism
Pyruvate Kinase genetics
Receptors, Steroid
Transcription Factors metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 274
- Issue :
- 40
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 10497199
- Full Text :
- https://doi.org/10.1074/jbc.274.40.28385