Interference between DNA binding activities of AP-1 and GR transcription factors in rat thymocytes undergoing dexamethasone-induced apoptosis

Ewa Sikora, Gian Paolo Rossini, Emanuela Grassilli, Enrica Bellesia, Paolo Salomoni, Claudio Franceschi

Research output: Contribution to journalArticle

Abstract

The early molecular events of glucocorticoid-induced apoptosis have been investigated by studying glucocorticoid receptor levels, as well as binding activities to GRE and AP-1 sequences, using nuclear extracts from dexamethasone (Dex)-treated rat thymocytes. When the time-course of glucocorticoid-receptor complexes in nuclei of thymocytes was evaluated by binding studies using the tritiated ligand, we found that nuclear accumulation of radioactive complexes occurred in the first hour of incubation, and was followed by a progressive decline. This trend was confirmed by immunoblotting of nuclear proteins using a monoclonal anti-glucocorticoid receptor antibody. When the kinetics of binding activity to AP-1 and GRE sequences were studied, using nuclear extracts prepared from Dex-treated thymocytes in gel shift assays, we found peaks at 1 and 2 h after Dex treatment, and a return to basal levels in the following hours. Binding specificity was proved by competition studies using non-radioactive sequences, including mutated AP-1. Unexpectedly, however, protein binding to GRE was better competed for by AP-1 sequence than by GRE itself. Data obtained using the super gel shift assay suggested that AP-1/Jun can be responsible for the high affinity for the GRE sequence. Thus, we report here for the first time that an interference between AP-1 and GR in the binding to DNA consensus sequences -previously described in other biological systems -also occurs during apoptosis induced by glucocorticoids in lymphoid cells.

Original languageEnglish
Pages (from-to)721-732
Number of pages12
JournalActa Biochimica Polonica
Volume43
Issue number4
Publication statusPublished - 1996

Fingerprint

Transcription Factor AP-1
Thymocytes
Dexamethasone
Rats
Transcription Factors
Apoptosis
DNA
Glucocorticoid Receptors
Glucocorticoids
Assays
Gels
DNA sequences
Consensus Sequence
Biological systems
Nuclear Proteins
Immunoblotting
Protein Binding
Lymphocytes
Ligands
Kinetics

Keywords

  • AP-1
  • Apoptosis
  • GR
  • Thymocytes
  • Transcription factors

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry

Cite this

Interference between DNA binding activities of AP-1 and GR transcription factors in rat thymocytes undergoing dexamethasone-induced apoptosis. / Sikora, Ewa; Rossini, Gian Paolo; Grassilli, Emanuela; Bellesia, Enrica; Salomoni, Paolo; Franceschi, Claudio.

In: Acta Biochimica Polonica, Vol. 43, No. 4, 1996, p. 721-732.

Research output: Contribution to journalArticle

Sikora, Ewa ; Rossini, Gian Paolo ; Grassilli, Emanuela ; Bellesia, Enrica ; Salomoni, Paolo ; Franceschi, Claudio. / Interference between DNA binding activities of AP-1 and GR transcription factors in rat thymocytes undergoing dexamethasone-induced apoptosis. In: Acta Biochimica Polonica. 1996 ; Vol. 43, No. 4. pp. 721-732.
@article{20c7639cf20d4b879d513fb0b0575e53,
title = "Interference between DNA binding activities of AP-1 and GR transcription factors in rat thymocytes undergoing dexamethasone-induced apoptosis",
abstract = "The early molecular events of glucocorticoid-induced apoptosis have been investigated by studying glucocorticoid receptor levels, as well as binding activities to GRE and AP-1 sequences, using nuclear extracts from dexamethasone (Dex)-treated rat thymocytes. When the time-course of glucocorticoid-receptor complexes in nuclei of thymocytes was evaluated by binding studies using the tritiated ligand, we found that nuclear accumulation of radioactive complexes occurred in the first hour of incubation, and was followed by a progressive decline. This trend was confirmed by immunoblotting of nuclear proteins using a monoclonal anti-glucocorticoid receptor antibody. When the kinetics of binding activity to AP-1 and GRE sequences were studied, using nuclear extracts prepared from Dex-treated thymocytes in gel shift assays, we found peaks at 1 and 2 h after Dex treatment, and a return to basal levels in the following hours. Binding specificity was proved by competition studies using non-radioactive sequences, including mutated AP-1. Unexpectedly, however, protein binding to GRE was better competed for by AP-1 sequence than by GRE itself. Data obtained using the super gel shift assay suggested that AP-1/Jun can be responsible for the high affinity for the GRE sequence. Thus, we report here for the first time that an interference between AP-1 and GR in the binding to DNA consensus sequences -previously described in other biological systems -also occurs during apoptosis induced by glucocorticoids in lymphoid cells.",
keywords = "AP-1, Apoptosis, GR, Thymocytes, Transcription factors",
author = "Ewa Sikora and Rossini, {Gian Paolo} and Emanuela Grassilli and Enrica Bellesia and Paolo Salomoni and Claudio Franceschi",
year = "1996",
language = "English",
volume = "43",
pages = "721--732",
journal = "Acta Biochimica Polonica",
issn = "0001-527X",
publisher = "Acta Biochimica Polonica",
number = "4",

}

TY - JOUR

T1 - Interference between DNA binding activities of AP-1 and GR transcription factors in rat thymocytes undergoing dexamethasone-induced apoptosis

AU - Sikora, Ewa

AU - Rossini, Gian Paolo

AU - Grassilli, Emanuela

AU - Bellesia, Enrica

AU - Salomoni, Paolo

AU - Franceschi, Claudio

PY - 1996

Y1 - 1996

N2 - The early molecular events of glucocorticoid-induced apoptosis have been investigated by studying glucocorticoid receptor levels, as well as binding activities to GRE and AP-1 sequences, using nuclear extracts from dexamethasone (Dex)-treated rat thymocytes. When the time-course of glucocorticoid-receptor complexes in nuclei of thymocytes was evaluated by binding studies using the tritiated ligand, we found that nuclear accumulation of radioactive complexes occurred in the first hour of incubation, and was followed by a progressive decline. This trend was confirmed by immunoblotting of nuclear proteins using a monoclonal anti-glucocorticoid receptor antibody. When the kinetics of binding activity to AP-1 and GRE sequences were studied, using nuclear extracts prepared from Dex-treated thymocytes in gel shift assays, we found peaks at 1 and 2 h after Dex treatment, and a return to basal levels in the following hours. Binding specificity was proved by competition studies using non-radioactive sequences, including mutated AP-1. Unexpectedly, however, protein binding to GRE was better competed for by AP-1 sequence than by GRE itself. Data obtained using the super gel shift assay suggested that AP-1/Jun can be responsible for the high affinity for the GRE sequence. Thus, we report here for the first time that an interference between AP-1 and GR in the binding to DNA consensus sequences -previously described in other biological systems -also occurs during apoptosis induced by glucocorticoids in lymphoid cells.

AB - The early molecular events of glucocorticoid-induced apoptosis have been investigated by studying glucocorticoid receptor levels, as well as binding activities to GRE and AP-1 sequences, using nuclear extracts from dexamethasone (Dex)-treated rat thymocytes. When the time-course of glucocorticoid-receptor complexes in nuclei of thymocytes was evaluated by binding studies using the tritiated ligand, we found that nuclear accumulation of radioactive complexes occurred in the first hour of incubation, and was followed by a progressive decline. This trend was confirmed by immunoblotting of nuclear proteins using a monoclonal anti-glucocorticoid receptor antibody. When the kinetics of binding activity to AP-1 and GRE sequences were studied, using nuclear extracts prepared from Dex-treated thymocytes in gel shift assays, we found peaks at 1 and 2 h after Dex treatment, and a return to basal levels in the following hours. Binding specificity was proved by competition studies using non-radioactive sequences, including mutated AP-1. Unexpectedly, however, protein binding to GRE was better competed for by AP-1 sequence than by GRE itself. Data obtained using the super gel shift assay suggested that AP-1/Jun can be responsible for the high affinity for the GRE sequence. Thus, we report here for the first time that an interference between AP-1 and GR in the binding to DNA consensus sequences -previously described in other biological systems -also occurs during apoptosis induced by glucocorticoids in lymphoid cells.

KW - AP-1

KW - Apoptosis

KW - GR

KW - Thymocytes

KW - Transcription factors

UR - http://www.scopus.com/inward/record.url?scp=0030334735&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030334735&partnerID=8YFLogxK

M3 - Article

C2 - 9104510

AN - SCOPUS:0030334735

VL - 43

SP - 721

EP - 732

JO - Acta Biochimica Polonica

JF - Acta Biochimica Polonica

SN - 0001-527X

IS - 4

ER -