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Titolo:
HORMONAL-REGULATION OF THE CHOLESTEROL 7-ALPHA-HYDROXYLASE GENE (CYP7)
Autore:
CRESTANI M; STROUP D; CHIANG JYL;
Indirizzi:
NE OHIO UNIV,COLL MED,DEPT BIOCHEM & MOLEC PATHOL,4209 STATE ROUTE 44,POB 95 ROOTSTOWN OH 44272 NE OHIO UNIV,COLL MED,DEPT BIOCHEM & MOLEC PATHOL ROOTSTOWN OH 44272
Titolo Testata:
Journal of lipid research
fascicolo: 11, volume: 36, anno: 1995,
pagine: 2419 - 2432
SICI:
0022-2275(1995)36:11<2419:HOTC7G>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
BILE-ACID SYNTHESIS; PHOSPHOENOLPYRUVATE CARBOXYKINASE GENE; MESSENGER-RNA LEVELS; PROTEIN-KINASE-C; TRANSCRIPTIONAL REGULATION; HEPATOMA-CELLS; EXTRACELLULAR-MATRIX; ALPHA-HYDROXYLASE; RAT HEPATOCYTES; RETINOIC ACID;
Keywords:
CHOLESTEROL 7-ALPHA-HYDROXYLASE; HEPG2 CELLS; GENE REGULATION; HORMONES; 2ND MESSENGERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
67
Recensione:
Indirizzi per estratti:
Citazione:
M. Crestani et al., "HORMONAL-REGULATION OF THE CHOLESTEROL 7-ALPHA-HYDROXYLASE GENE (CYP7)", Journal of lipid research, 36(11), 1995, pp. 2419-2432

Abstract

The transcriptional regulation of the rat cholesterol 7 alpha-hydroxylase gene (CYP7) by hormones and signal transduction pathways was studied by transient transfection assay of the promoter activity. HepG2 cells were transfected with deletion mutants of the CYP7 upstream regionlinked to the luciferase reporter gene. The transcription of CYP7/luciferase chimeric genes was higher in confluent than in subconfluent cultures of HepG2 cells. Glucocorticoid receptors, in the presence of dexamethasone, up-regulated the CYP7 gene through two regions located between -3262 and -2803, and between -344 and -222, respectively. Thyroid hormones did not have any effect on the promoter activity. Insulin inhibited the promoter activity through sequences located between -344 and -222, and abolished the stimulation by dexamethasone. Hence, the insulin effect was dominant over that of glucocorticoids. Treatment of transfected HepG2 cells with phorbol 12-myristate 13-acetate (PMA), a known activator of protein kinase C (PKC), resulted in a time-dependent inhibition of the CYP7 promoter activity. The negative phorbol ester-response sequences were mapped between -344 and -222, and between -200 and -161, respectively. The CYP7 promoter activity was induced nearly Ei-fold by all-trans-retinoic acid through sequences in the region from -200 to -129. Finally, cyclic AMP and protein kinase A (PKA) stimulated the expression of the CYP7/luciferase gene through multiple sequences in the distal and proximal regions, and both positive and negative response regions were mapped. Our results revealed that the -416 fragment of the rat CYP7 gene confers the activation by glucocorticoids and retinoic acid, and inhibition by insulin, phorbol esters and cAMP. It appears that this proximal promoter may contain a pleiotropic domain that regulates the effects of multiple signals.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/10/20 alle ore 02:56:49