scholarly journals Colocalization and Ligand-Dependent Discrete Distribution of the Estrogen Receptor (ER)α and ERβ

2002 ◽  
Vol 16 (10) ◽  
pp. 2215-2230 ◽  
Author(s):  
Ken-ichi Matsuda ◽  
Ikuo Ochiai ◽  
Mayumi Nishi ◽  
Mitsuhiro Kawata
Keyword(s):  
Estrogen Receptor ◽  
Dna Binding ◽  
Time Course ◽  
Structural Changes ◽  
Fluorescent Protein ◽  
Cluster Formation ◽  
Discrete Distribution ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Similar Time

Abstract To investigate the relationships between the loci expressing functions of estrogen receptor (ER)α and that of ERβ, we analyzed the subnuclear distribution of ERα and ERβ in response to ligand in single living cells using fusion proteins labeled with different spectral variants of green fluorescent protein. Upon activation with ligand treatment, fluorescent protein-tagged (FP)-ERβ redistributed from a diffuse to discrete pattern within the nucleus, showing a similar time course as FP-ERα, and colocalized with FP-ERα in the same discrete cluster. Analysis using deletion mutants of ERα suggested that the ligand-dependent redistribution of ERα might occur through a large part of the receptor including at least the latter part of activation function (AF)-1, the DNA binding domain, nuclear matrix binding domain, and AF-2/ligand binding domain. In addition, a single AF-1 region within ERα homodimer, or a single DNA binding domain as well as AF-1 region within the ERα/ERβ heterodimer, could be sufficient for the cluster formation. More than half of the discrete clusters of FP-ERα and FP-ERβ were colocalized with hyperacetylated histone H4 and a component of the chromatin remodeling complex, Brg-1, indicating that ERs clusters might be involved in structural changes of chromatin.

scholarly journals Functional domains of interferon regulatory factor I (IRF-1)

1998 ◽  
Vol 335 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Fred SCHAPER ◽  
Sabine KIRCHHOFF ◽  
Guido POSERN ◽  
Mario KÖSTER ◽  
André OUMARD ◽  
...  
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Consensus Sequence ◽  
Binding Domain ◽  
Functional Domains ◽  
Dna Binding Domain ◽  
Transcriptional Activation Domain

Interferon (IFN) regulatory factors (IRFs) are a family of transcription factors among which are IRF-1, IRF-2, and IFN consensus sequence binding protein (ICSBP). These factors share sequence homology in the N-terminal DNA-binding domain. IRF-1 and IRF-2 are further related and have additional homologous sequences within their C-termini. Whereas IRF-2 and ICSBP are identified as transcriptional repressors, IRF-1 is an activator. In the present work, the identification of functional domains in murine IRF-1 with regard to DNA-binding, nuclear translocation, heterodimerization with ICSBP and transcriptional activation are demonstrated. The minimal DNA-binding domain requires the N-terminal 124 amino acids plus an arbitrary C-terminal extension. By using mutants of IRF-1 fusion proteins with green fluorescent protein and monitoring their distribution in living cells, a nuclear location signal (NLS) was identified and found to be sufficient for nuclear translocation. Heterodimerization was confirmed by a two-hybrid system adapted to mammalian cells. The heterodimerization domain in IRF-1 was defined by studies in vitroand was shown to be homologous with a sequence in IRF-2, suggesting that IRF-2 also heterodimerizes with ICSBP through this sequence. An acidic domain in IRF-1 was found to be required and to be sufficient for transactivation. Epitope mapping of IRF-1 showed that regions within the NLS, the heterodimerization domain and the transcriptional activation domain are exposed for possible contacts with interacting proteins.

Binding of the estrogen receptor DNA-binding domain to the estrogen response element induces DNA bending

1992 ◽  
Vol 12 (5) ◽  
pp. 2037-2042
Author(s):  
A M Nardulli ◽  
D J Shapiro
Keyword(s):  
Estrogen Receptor ◽  
Dna Binding ◽  
Dna Bending ◽  
Binding Domain ◽  
Estrogen Response Element ◽  
Dna Binding Domain ◽  
Mobility Shift ◽  
Response Element ◽  
Estrogen Response ◽  
Dna Fragment

We have used circular permutation analysis to determine whether binding of purified Xenopus laevis estrogen receptor DNA-binding domain (DBD) to a DNA fragment containing an estrogen response element (ERE) causes the DNA to bend. Gel mobility shift assays showed that DBD-DNA complexes formed with fragments containing more centrally located EREs migrated more slowly than complexes formed with fragments containing EREs near the ends of the DNA. DNA bending standards were used to determine that the degree of bending induced by binding of the DBD to an ERE was approximately 34 degrees. A 1.55-fold increase in the degree of bending was observed when two EREs were present in the DNA fragment. These in vitro studies suggest that interaction of nuclear receptors with their hormone response elements in vivo may result in an altered DNA conformation.

scholarly journals Prebending the estrogen response element destabilizes binding of the estrogen receptor DNA binding domain.

1997 ◽  
Vol 17 (6) ◽  
pp. 3173-3180 ◽  
Author(s):  
J Kim ◽  
G de Haan ◽  
A M Nardulli ◽  
D J Shapiro
Keyword(s):  
Estrogen Receptor ◽  
Transcription Factor ◽  
Dna Binding ◽  
Minor Groove ◽  
Dna Topology ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Eukaryotic Transcription ◽  
Estrogen Response ◽  
Direct Demonstration

Binding of many eukaryotic transcription regulatory proteins to their DNA recognition sequences results in conformational changes in DNA. To test the effect of altering DNA topology by prebending a transcription factor binding site, we examined the interaction of the estrogen receptor (ER) DNA binding domain (DBD) with prebent estrogen response elements (EREs). When the ERE in minicircle DNA was prebent toward the major groove, which is in the same direction as the ER-induced DNA bend, there was no significant effect on ER DBD binding relative to the linear counterparts. However, when the ERE was bent toward the minor groove, in a direction that opposes the ER-induced DNA bend, there was a four- to eightfold reduction in ER DBD binding. Since reduced binding was also observed with the ERE in nicked circles, the reduction in binding was not due to torsional force induced by binding of ER DBD to the prebent ERE in covalently closed minicircles. To determine the mechanism responsible for reduced binding to the prebent ERE, we examined the effect of prebending the ERE on the association and dissociation of the ER DBD. Binding of the ER DBD to ERE-containing minicircles was rapid when the EREs were prebent toward either the major or minor groove of the DNA (k(on) of 9.9 x 10(6) to 1.7 x 10(7) M(-1) s(-1)). Prebending the ERE toward the minor groove resulted in an increase in k(off) of four- to fivefold. Increased dissociation of the ER DBD from the ERE is, therefore, the major factor responsible for reduced binding of the ER DBD to an ERE prebent toward the minor groove. These data provide the first direct demonstration that the interaction of a eukaryotic transcription factor with its recognition sequence can be strongly influenced by altering DNA topology through prebending the DNA.

scholarly journals Phosphorylation of Human Estrogen Receptor α by Protein Kinase A Regulates Dimerization

1999 ◽  
Vol 19 (2) ◽  
pp. 1002-1015 ◽  
Author(s):  
Dongsheng Chen ◽  
Paul E. Pace ◽  
R. Charles Coombes ◽  
Simak Ali
Keyword(s):  
Estrogen Receptor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Ligand Binding ◽  
Protein Kinase A ◽  
Estrogen Receptor Α ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Ici 182,780 ◽  
Kinase A

ABSTRACT Phosphorylation provides an important mechanism by which transcription factor activity is regulated. Estrogen receptor α (ERα) is phosphorylated on multiple sites, and stimulation of a number of growth factor receptors and/or protein kinases leads to ligand-independent and/or synergistic increase in transcriptional activation by ERα in the presence of estrogen. Here we show that ERα is phosphorylated by protein kinase A (PKA) on serine-236 within the DNA binding domain. Mutation of serine-236 to glutamic acid prevents DNA binding by inhibiting dimerization by ERα, whereas mutation to alanine has little effect on DNA binding or dimerization. Furthermore, PKA overexpression or activation of endogenous PKA inhibits dimerization in the absence of ligand. This inhibition is overcome by the addition of 17β-estradiol or the partial agonist 4-hydroxy tamoxifen. Interestingly, treatment with the complete antagonist ICI 182,780 does not overcome the inhibitory effect of PKA activation. Our results indicate that in the absence of ligand ERα forms dimers through interaction between DNA binding domains and that dimerization mediated by the ligand binding domain only occurs upon ligand binding but that the complete antagonist ICI 182,780 prevents dimerization through the ligand-binding domain. Heterodimer formation between ERα and ERβ is similarly affected by PKA phosphorylation of serine 236 of ERα. However, 4-hydroxytamoxifen is unable to overcome inhibition of dimerization by PKA. Thus, phosphorylation of ERα in the DNA binding domain provides a mechanism by which dimerization and thereby DNA binding by the estrogen receptor is regulated.

scholarly journals Dynamic Cell Type Specificity of SRC-1 Coactivator in Modulating Uterine Progesterone Receptor Function in Mice

2005 ◽  
Vol 25 (18) ◽  
pp. 8150-8165 ◽  
Author(s):  
Sang Jun Han ◽  
Jaewook Jeong ◽  
Francesco J. DeMayo ◽  
Jianming Xu ◽  
Sophia Y. Tsai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Progesterone Receptor ◽  
Gene Transcription ◽  
Fluorescent Protein ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Female Reproduction ◽  
Functional Relationships ◽  
A Cell

ABSTRACT Regulation of gene transcription by the progesterone receptor (PR) in cooperation with coactivator/corepressor complexes coordinates crucial processes in female reproduction. To investigate functional relationships between PR and steroid receptor coactivators (SRCs) in distinct cell types of uterine tissue during gene transcription, we generated a new transgenic mouse model utilizing a Progesterone Receptor Activity Indicator (PRAI) system that could monitor PR activity in vivo. The PRAI system consists of a modified PR bacterial artificial chromosome (BAC) clone in which the DNA binding domain of the PR was replaced with the yeast Gal4 DNA binding domain. A humanized green fluorescent protein (hrGFP) reporter controlled by the Upstream Activating Sequences for the Gal4 gene (UASG) was inserted in tandem with the modified PR gene. Expression of hrGFP in the uterus demonstrated that the PRAI animal model faithfully replicated PR signaling under various endocrine states. Bigenic PRAI-SRC-1−/− mice revealed that SRC-1 modulates PR activity in the uterus in a cell-specific fashion and is involved in PR gene activation in stroma and myometrium of the uterus in response to estrogen and progesterone. In contrast, SRC-1 was involved in the down-regulation of PR target gene expression in the luminal and glandular epithelial compartments of the uterus after chronic progesterone treatment. Finally, we dissected the means by which SRC-1 dynamically regulates PR activity in each uterine cell compartment and demonstrated that it involves the differential ability of SRC-1 to modulate expression levels of distinct coactivators, corepressors, and PR in a cell-specific fashion.

Sign in / Sign up

Export Citation Format

Share Document