CHICKEN OVALBUMIN UPSTREAM-PROMOTER TRANSCRIPTION FACTOR (COUP-TF) COULD ACT AS A TRANSCRIPTIONAL ACTIVATOR OR REPRESSOR OF THE MITOCHONDRIAL 3-HYDROXY-3-METHYLGLUTARYL-COA SYNTHASE GENE
Jc. Rodriguez et al., CHICKEN OVALBUMIN UPSTREAM-PROMOTER TRANSCRIPTION FACTOR (COUP-TF) COULD ACT AS A TRANSCRIPTIONAL ACTIVATOR OR REPRESSOR OF THE MITOCHONDRIAL 3-HYDROXY-3-METHYLGLUTARYL-COA SYNTHASE GENE, Biochemical journal, 326, 1997, pp. 587-592
The chicken ovalbumin upstream-promoter transcription factor (COUP-TF)
has a dual effect on the regulation of the mitochondrial 3-hydroxy-3-
methylglutaryl-CoA (HMG-CoA) synthase gene. COUP-TF could act as a tra
nscriptional activator or repressor of this gene through different DNA
sequences. COUP-TF induces expression of a reporter gene linked to th
e mitochondrial HMG-CoA synthase gene promoter in human hepatoma HepG2
cells, but represses it in a Leydig tumour cell line (R2C); in bath t
hese cell lines the expression of the mitochondrial HMG-CoA synthase g
ene mimics that of liver and testis. The activation is promoted by a f
ragment of the gene from coordinates -62 to +28, which contains a GC b
ox and a TATA box, and where no COUP-TF binding site was observed by i
n vitro DNA binding studies. On the other hand, the COUP-TF inhibitory
effect is mainly due to repression of peroxisome-proliferator-activat
ed receptor-dependent activation of the gene, interacting with the reg
ion from -104 to -92. To our knowledge this work represents the second
example of a target gene for COUP-TF I that could be either activated
or repressed by the action of this receptor through different DNA seq
uences of the same gene.