CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
artículos
Título:
Thyroid hormone receptor Ò1 gene expression is increased by dexamethasone at transcriptional level in rat liver
Autor/es:
MONTESINOS MM; PELLIZAS CG; VÉLEZ ML; SUSPERREGUY S; MASINI-REPISO AM; COLEONI AH
Revista:
LIFE SCIENCES
Editorial:
Elsevier
Referencias:
Año: 2006 vol. 78 p. 2584 - 2594
ISSN:
0024-3205
Resumen:
Triiodothyronine (T3) exerts most of its effect through nuclear thyroid hormone receptors (TR) which bind mainly as heterodimers with
retinoid-X receptors (RXR) to thyroid hormone response elements (TRE) in target genes. It is well known that the synergistic interaction of T3 and
glucocorticoids has a role on the synthesis of growth hormone in rat pituitary cell lines and in the T3-induced metamorphosis in amphibians.
Glucocorticoids increased mRNAs of T3-regulated hepatic genes. Our laboratory reported increased specific metabolic actions of T3 in rat liver by
Dexamethasone (Dex) through a mechanism involving an up-regulation of the maximal binding capacity of TR.
In this study we further explored the participation of TR in the molecular mechanism of the Dex-induced increase on liver T3-specific
metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRh1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.3) exerts most of its effect through nuclear thyroid hormone receptors (TR) which bind mainly as heterodimers with
retinoid-X receptors (RXR) to thyroid hormone response elements (TRE) in target genes. It is well known that the synergistic interaction of T3 and
glucocorticoids has a role on the synthesis of growth hormone in rat pituitary cell lines and in the T3-induced metamorphosis in amphibians.
Glucocorticoids increased mRNAs of T3-regulated hepatic genes. Our laboratory reported increased specific metabolic actions of T3 in rat liver by
Dexamethasone (Dex) through a mechanism involving an up-regulation of the maximal binding capacity of TR.
In this study we further explored the participation of TR in the molecular mechanism of the Dex-induced increase on liver T3-specific
metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRh1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.3 and
glucocorticoids has a role on the synthesis of growth hormone in rat pituitary cell lines and in the T3-induced metamorphosis in amphibians.
Glucocorticoids increased mRNAs of T3-regulated hepatic genes. Our laboratory reported increased specific metabolic actions of T3 in rat liver by
Dexamethasone (Dex) through a mechanism involving an up-regulation of the maximal binding capacity of TR.
In this study we further explored the participation of TR in the molecular mechanism of the Dex-induced increase on liver T3-specific
metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRh1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.3-induced metamorphosis in amphibians.
Glucocorticoids increased mRNAs of T3-regulated hepatic genes. Our laboratory reported increased specific metabolic actions of T3 in rat liver by
Dexamethasone (Dex) through a mechanism involving an up-regulation of the maximal binding capacity of TR.
In this study we further explored the participation of TR in the molecular mechanism of the Dex-induced increase on liver T3-specific
metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRh1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.3-regulated hepatic genes. Our laboratory reported increased specific metabolic actions of T3 in rat liver by
Dexamethasone (Dex) through a mechanism involving an up-regulation of the maximal binding capacity of TR.
In this study we further explored the participation of TR in the molecular mechanism of the Dex-induced increase on liver T3-specific
metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRh1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.3-specific
metabolic action. Dex administration to adrenalectomized rats induced an increase of liver TRh1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.h1 protein and mRNA. Nuclear run-on assay
revealed that Dex up-regulated the TR gene transcriptional rate. Transfection assay in COS-7 cells indicated that Dex increased the transcriptional
activity of the TRh1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.h1 promoter. Electrophoretic mobility shift assay demonstrated that Dex induced the binding of additional proteins related to or
neighboring the DNA sequence of a glucocorticoid receptor (GR) binding (GRE) half-site in the TRh1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.h1 promoter. Evidences for an interaction of
GR on the TRh1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.h1 promoter have been obtained. Moreover, the specificity of the GR binding to GRE was determined not only by the GRE DNA
sequence, but also by the interaction of the GR with other transacting factors bound to sequences flanking the GRE.