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Titolo:
DIFFERENTIAL-EFFECTS OF A TOPOISOMERASE-I INHIBITOR ON DIOXIN INDUCIBILITY AND HIGH-LEVEL EXPRESSION OF THE CYTOCHROME P450IA1 GENE
Autore:
GRADIN K; TOFTGARD R; BERGHARD A;
Indirizzi:
KAROLINSKA INST,NOVUM,DEPT BIOSCI,CTR NUTR & TOXICOL S-14157 HUDDINGESWEDEN
Titolo Testata:
Molecular pharmacology
fascicolo: 4, volume: 48, anno: 1995,
pagine: 610 - 615
SICI:
0026-895X(1995)48:4<610:DOATIO>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
RNA POLYMERASE-II; AH-RECEPTOR; TRANSCRIPTION FACTOR; P-450C GENE; DNA; MECHANISM; REPRESSION; ACTIVATION; INDUCTION; CLONING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
43
Recensione:
Indirizzi per estratti:
Citazione:
K. Gradin et al., "DIFFERENTIAL-EFFECTS OF A TOPOISOMERASE-I INHIBITOR ON DIOXIN INDUCIBILITY AND HIGH-LEVEL EXPRESSION OF THE CYTOCHROME P450IA1 GENE", Molecular pharmacology, 48(4), 1995, pp. 610-615

Abstract

The basic helix-loop-helix containing dioxin receptor mediates dioxinsignal transduction. The ligand-activated receptor complex binds to specific sequences termed xenobiotic response elements and regulates transcription of target genes such as the gene for cytochrome P450IA1. This study demonstrates that induction of cytochrome P450IA1 and P450IB1 gene expression by a dioxin receptor ligand is repressed by camptothecin, an inhibitor of the topoisomerase I enzyme. However, a transiently transfected reporter construct under control of an xenobiotic response element-containing promoter was not affected by the topoisomerase inhibitor. In agreement with this observation, ligand-dependent activation of the dioxin receptor to its DNA-binding form is not altered by camptothecin as analyzed by electrophoretic mobility shift assay. Moreover, the inhibitory effect of camptothecin cannot be exerted once theP450IA1 gene has been activated. These results imply that topoisomerase I activity is necessary for the primary P450IA1 induction response,possibly involving dioxin-dependent alterations in chromatin structure of the P450IA1 promoter.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 17:42:38