1
|
Wang LH, Chen LR, Chen KH. In Vitro and Vivo Identification, Metabolism and Action of Xenoestrogens: An Overview. Int J Mol Sci 2021; 22:4013. [PMID: 33924608 PMCID: PMC8070283 DOI: 10.3390/ijms22084013] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 12/12/2022] Open
Abstract
Xenoestrogens (XEs) are substances that imitate endogenous estrogens to affect the physiologic functions of humans or other animals. As endocrine disruptors, they can be either synthetic or natural chemical compounds derived from diet, pesticides, cosmetics, plastics, plants, industrial byproducts, metals, and medications. By mimicking the chemical structure that is naturally occurring estrogen compounds, synthetic XEs, such as polychlorinated biphenyls (PCBs), bisphenol A (BPA), and diethylstilbestrol (DES), are considered the focus of a group of exogenous chemical. On the other hand, nature phytoestrogens in soybeans can also serve as XEs to exert estrogenic activities. In contrast, some XEs are not similar to estrogens in structure and can affect the physiologic functions in ways other than ER-ERE ligand routes. Studies have confirmed that even the weakly active compounds could interfere with the hormonal balance with persistency or high concentrations of XEs, thus possibly being associated with the occurrence of the reproductive tract or neuroendocrine disorders and congenital malformations. However, XEs are most likely to exert tissue-specific and non-genomic actions when estrogen concentrations are relatively low. Current research has reported that there is not only one factor affected by XEs, but opposite directions are also found on several occasions, or even different components stem from the identical endocrine pathway; thus, it is more challenging and unpredictable of the physical health. This review provides a summary of the identification, detection, metabolism, and action of XEs. However, many details of the underlying mechanisms remain unknown and warrant further investigation.
Collapse
Affiliation(s)
- Li-Hsuan Wang
- Department of Obstetrics and Gynecology, Taipei Tzu-Chi Hospital, The Buddhist Tzu-Chi Medical Foundation, Taipei 231, Taiwan;
| | - Li-Ru Chen
- Department of Physical Medicine and Rehabilitation, Mackay Memorial Hospital, Taipei 10049, Taiwan;
- Department of Mechanical Engineering, National Yang-Ming Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Kuo-Hu Chen
- Department of Obstetrics and Gynecology, Taipei Tzu-Chi Hospital, The Buddhist Tzu-Chi Medical Foundation, Taipei 231, Taiwan;
- School of Medicine, Tzu-Chi University, Hualien 970, Taiwan
| |
Collapse
|
2
|
Anderson AP, Rose E, Flanagan SP, Jones AG. The Estrogen-Responsive Transcriptome of Female Secondary Sexual Traits in the Gulf Pipefish. J Hered 2020; 111:294-306. [PMID: 32124926 DOI: 10.1093/jhered/esaa008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/24/2020] [Indexed: 01/01/2023] Open
Abstract
Sexual dimorphism often results from hormonally regulated trait differences between the sexes. In sex-role-reversed vertebrates, females often have ornaments used in mating competition that are expected to be under hormonal control. Males of the sex-role-reversed Gulf pipefish (Syngnathus scovelli) develop female-typical traits when they are exposed to estrogens. We aimed to identify genes whose expression levels changed during the development and maintenance of female-specific ornaments. We performed RNA-sequencing on skin and muscle tissue in male Gulf pipefish with and without exposure to estrogen to investigate the transcriptome of the sexually dimorphic ornament of vertical iridescent bands found in females and estrogen-exposed males. We further compared differential gene expression patterns between males and females to generate a list of genes putatively involved in the female secondary sex traits of bands and body depth. A detailed analysis of estrogen-receptor binding sites demonstrates that estrogen-regulated genes tend to have nearby cis-regulatory elements. Our results identified a number of genes that differed between the sexes and confirmed that many of these were estrogen-responsive. These estrogen-regulated genes may be involved in the arrangement of chromatophores for color patterning, as well as in the growth of muscles to achieve the greater body depth typical of females in this species. In addition, anaerobic respiration and adipose tissue could be involved in the rigors of female courtship and mating competition. Overall, this study generates a number of interesting hypotheses regarding the genetic basis of a female ornament in a sex-role-reversed pipefish.
Collapse
Affiliation(s)
| | - Emily Rose
- Department of Biology, University of Tampa, Tampa, FL
| | - Sarah P Flanagan
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Adam G Jones
- Department of Biological Sciences, University of Idaho, Moscow, ID
| |
Collapse
|
3
|
Pallares RM, Thanh NTK, Su X. Quantifying the binding between proteins and open chromatin-like DNA sequences with gold nanorods. Chem Commun (Camb) 2019; 55:15041-15044. [PMID: 31696164 DOI: 10.1039/c9cc07511a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The binding of transcription factors to DNA is one of the main mechanisms in gene regulation. While transcription factors frequently bind to unwrapped long DNA sequences known as open chromatin structures, most bioassays that study protein-DNA binding rely on short oligonucleotide probes. In this work, we develop a gold nanorod-based colorimetric assay for the binding of transcription factors to DNA in long open chromatin-like structures. After the determination of the binding affinity and stoichiometry, we explored the effect of the probe length on the assay performance and compared it to other established techniques.
Collapse
Affiliation(s)
- Roger M Pallares
- Biophysics Group, Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK.
| | | | | |
Collapse
|
4
|
Anderson AP, Jones AG. erefinder: Genome-wide detection of oestrogen response elements. Mol Ecol Resour 2019; 19:1366-1373. [PMID: 31177626 DOI: 10.1111/1755-0998.13046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 05/31/2019] [Accepted: 05/31/2019] [Indexed: 11/28/2022]
Abstract
Oestrogen response elements (EREs) are specific DNA sequences to which ligand-bound oestrogen receptors (ERs) physically bind, allowing them to act as transcription factors for target genes. Locating EREs and ER responsive regions is therefore a potentially important component of the study of oestrogen-regulated pathways. Here, we report the development of a novel software tool, erefinder, which conducts a genome-wide, sliding-window analysis of oestrogen receptor binding affinity. We demonstrate the effects of adjusting window size and highlight the program's general agreement with ChIP studies. We further provide two examples of how erefinder can be used for comparative approaches. erefinder can handle large input files, has settings to allow for broad and narrow searches, and provides the full output to allow for greater data manipulation. These features facilitate a wide range of hypothesis testing for researchers and make erefinder an excellent tool to aid in oestrogen-related research.
Collapse
Affiliation(s)
- Andrew P Anderson
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Adam G Jones
- Department of Biological Sciences, University of Idaho, Moscow, ID, USA
| |
Collapse
|
5
|
Yu Z, Guo C, Wei Y, Hashiya K, Bando T, Sugiyama H. Pip-HoGu: An Artificial Assembly with Cooperative DNA Recognition Capable of Mimicking Transcription Factor Pairs. J Am Chem Soc 2018; 140:2426-2429. [DOI: 10.1021/jacs.7b13275] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Zutao Yu
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Chuanxin Guo
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Yulei Wei
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Kaori Hashiya
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Toshikazu Bando
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Hiroshi Sugiyama
- Department
of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
- Institute for Integrated Cell-Material Sciences
(WPI-iCeMS), Kyoto University, Sakyo, Kyoto 606-8501, Japan
| |
Collapse
|
6
|
Gapsys V, de Groot BL. Alchemical Free Energy Calculations for Nucleotide Mutations in Protein–DNA Complexes. J Chem Theory Comput 2017; 13:6275-6289. [DOI: 10.1021/acs.jctc.7b00849] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vytautas Gapsys
- Computational Biomolecular
Dynamics Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Bert L. de Groot
- Computational Biomolecular
Dynamics Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| |
Collapse
|
7
|
Le Grand A, André-Leroux G, Marteil G, Duval H, Sire O, Le Tilly V. Investigating the in Vitro Thermal Stability and Conformational Flexibility of Estrogen Receptors as Potential Key Factors of Their in Vivo Activity. Biochemistry 2015; 54:3890-900. [DOI: 10.1021/acs.biochem.5b00026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adélaïde Le Grand
- Laboratoire
d’Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Gwenaëlle André-Leroux
- Institut National de la Recherche
Agronomique, UR1404, Unité de Mathématiques et Informatiques
Appliquées du Génome à l’Environnement, Domaine de Vilvert, 78352 Jouy-en-Josas, France
- Institut
Pasteur,
Unité de Microbiologie Structurale, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris, France
| | - Gaëlle Marteil
- Instituto Gulbenkian de Ciëncia, Cell Cycle
Regulation Lab, Rua da
Quinta Grande, P-2780-156 Oreias, Portugal
| | - Hélène Duval
- Laboratoire
d’Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Olivier Sire
- Laboratoire
d’Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Véronique Le Tilly
- Laboratoire
d’Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| |
Collapse
|
8
|
Le Grand A, Bouter A, Couturier A, Mulner-Lorillon O, Le Goff X, Chesnel F, Sire O, Le Tilly V. Investigation of the functional properties and subcellular localization of alpha human and rainbow trout estrogen receptors within a unique yeast cellular context. J Steroid Biochem Mol Biol 2015; 149:17-26. [PMID: 25595040 DOI: 10.1016/j.jsbmb.2015.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/26/2014] [Accepted: 01/11/2015] [Indexed: 12/22/2022]
Abstract
Estrogens are steroid hormones that play a pivotal role in growth, differentiation and function of reproductive and non-reproductive tissues, mediated through estrogen receptors (ERs). Estrogens are involved in different genomic and non-genomic cell signaling pathways which involve well-defined subcellular ER localizations. Thus, ER activity results from complex interplays between intrinsic binding properties and specific subcellular localization. Since these two factors are deeply intricate, we carried out, in a unique yeast cell context, a comparative study to better understand structure/function/subcellular distribution relationships. This was carried out by comparing two ERs: the human ER α subtype (hERα) and the short form of the α isoform of the rainbow trout ER (rtERαS). Their distinct binding properties to agonist and antagonist ligands and subcellular localizations were characterized in Saccharomyces cerevisiae yeast cells. An unexpected partial agonistic effect of ICI 182-780 was observed for rtERαS. Concomitant to distinct binding properties, distinct subcellular localizations were observed before and after ligand stimulation. Due to the unique cell context, the link between ERs intrinsic binding properties and subcellular localizations is partly unveiled and issues are hypothesized based on the role of cytoplasmic transient complexes which play a role in the ER cytoplasmic/nuclear partition, which in turn is critical for the recruitment of co-regulators in the nucleus.
Collapse
Affiliation(s)
- Adélaïde Le Grand
- Laboratoire d'Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Anthony Bouter
- Molecular Imaging and NanoBioTechnology, UMR 5248 CBMN, CNRS-Université Bordeaux 1-ENITAB, IECB, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Anne Couturier
- CNRS/Université de Rennes 1, Institut de Génétique & Développement de Rennes, UMR 6290, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Odile Mulner-Lorillon
- CNRS/UPMC Université Paris 06, UMR 8227 LBI2M, Traduction, Cycle Cellulaire et Développement, Station Biologique, CS 90074, 29688 Roscoff Cedex, France
| | - Xavier Le Goff
- CNRS/Université de Rennes 1, Institut de Génétique & Développement de Rennes, UMR 6290, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Franck Chesnel
- CNRS/Université de Rennes 1, Institut de Génétique & Développement de Rennes, UMR 6290, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Olivier Sire
- Laboratoire d'Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Véronique Le Tilly
- Laboratoire d'Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France.
| |
Collapse
|
9
|
Fattori J, Indolfo NDC, Campos JCLDO, Videira NB, Bridi AV, Doratioto TR, Assis MAD, Figueira ACM. Investigation of Interactions between DNA and Nuclear Receptors: A Review of the Most Used Methods. NUCLEAR RECEPTOR RESEARCH 2014. [DOI: 10.11131/2014/101090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Juliana Fattori
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| | - Nathalia de Carvalho Indolfo
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| | | | - Natália Bernardi Videira
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| | - Aline Villanova Bridi
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| | - Tábata Renée Doratioto
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| | - Michelle Alexandrino de Assis
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| | - Ana Carolina Migliorini Figueira
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), P.O. Box 6192, Campinas-SP, Brazil
| |
Collapse
|
10
|
Hudson WH, Youn C, Ortlund EA. Crystal structure of the mineralocorticoid receptor DNA binding domain in complex with DNA. PLoS One 2014; 9:e107000. [PMID: 25188500 PMCID: PMC4154765 DOI: 10.1371/journal.pone.0107000] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/12/2014] [Indexed: 01/21/2023] Open
Abstract
The steroid hormone receptors regulate important physiological functions such as reproduction, metabolism, immunity, and electrolyte balance. Mutations within steroid receptors result in endocrine disorders and can often drive cancer formation and progression. Despite the conserved three-dimensional structure shared among members of the steroid receptor family and their overlapping DNA binding preference, activation of individual steroid receptors drive unique effects on gene expression. Here, we present the first structure of the human mineralocorticoid receptor DNA binding domain, in complex with a canonical DNA response element. The overall structure is similar to the glucocorticoid receptor DNA binding domain, but small changes in the mode of DNA binding and lever arm conformation may begin to explain the differential effects on gene regulation by the mineralocorticoid and glucocorticoid receptors. In addition, we explore the structural effects of mineralocorticoid receptor DNA binding domain mutations found in type I pseudohypoaldosteronism and multiple types of cancer.
Collapse
MESH Headings
- Amino Acid Sequence
- Crystallography, X-Ray
- DNA/chemistry
- DNA/genetics
- DNA/metabolism
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- Humans
- Molecular Sequence Data
- Mutation
- Neoplasms/genetics
- Neoplasms/metabolism
- Neoplasms/pathology
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Pseudohypoaldosteronism/genetics
- Pseudohypoaldosteronism/metabolism
- Pseudohypoaldosteronism/pathology
- Receptors, Glucocorticoid/chemistry
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/metabolism
- Receptors, Mineralocorticoid/chemistry
- Receptors, Mineralocorticoid/genetics
- Receptors, Mineralocorticoid/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Alignment
- Structural Homology, Protein
Collapse
Affiliation(s)
- William H. Hudson
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Discovery and Developmental Therapeutics, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Christine Youn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Discovery and Developmental Therapeutics, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Eric A. Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Discovery and Developmental Therapeutics, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, United States of America
| |
Collapse
|
11
|
Clerte C, Declerck N, Margeat E. Competitive folding of anti-terminator/terminator hairpins monitored by single molecule FRET. Nucleic Acids Res 2013; 41:2632-43. [PMID: 23303779 PMCID: PMC3575810 DOI: 10.1093/nar/gks1315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The control of transcription termination by RNA-binding proteins that modulate RNA-structures is an important regulatory mechanism in bacteria. LicT and SacY from Bacillus subtilis prevent the premature arrest of transcription by binding to an anti-terminator RNA hairpin that overlaps an intrinsic terminator located in the 5'-mRNA leader region of the gene to be regulated. In order to investigate the molecular determinants of this anti-termination/termination balance, we have developed a fluorescence-based nucleic acids system that mimics the competition between the LicT or SacY anti-terminator targets and the overlapping terminators. Using Förster Resonance Energy Transfer on single diffusing RNA hairpins, we could monitor directly their opening or closing state, and thus investigate the effects on this equilibrium of the binding of anti-termination proteins or terminator-mimicking oligonucleotides. We show that the anti-terminator hairpins adopt spontaneously a closed structure and that their structural dynamics is mainly governed by the length of their basal stem. The induced stability of the anti-terminator hairpins determines both the affinity and specificity of the anti-termination protein binding. Finally, we show that stabilization of the anti-terminator hairpin, by an extended basal stem or anti-termination protein binding can efficiently counteract the competing effect of the terminator-mimic.
Collapse
Affiliation(s)
- Caroline Clerte
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France; INSERM U1054, 34090 Montpellier, France
| | | | | |
Collapse
|
12
|
Tools to evaluate estrogenic potency of dietary phytoestrogens:A consensus paper from the EU Thematic Network "Phytohealth" (QLKI-2002-2453). GENES AND NUTRITION 2012; 1:143-58. [PMID: 18850210 DOI: 10.1007/bf02829964] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 10/15/2006] [Indexed: 02/06/2023]
Abstract
Phytoestrogens are naturally occurring plantderived polyphenols with estrogenic potency. They are ubiquitous in diet and therefore, generally consumed. Among Europeans, the diet is rich in multiple putative phytoestrogens including flavonoids, tannins, stilbenoids, and lignans. These compounds have been suggested to provide beneficial effects on multiple menopause-related conditions as well as on development of hormone-dependent cancers, which has increased the interest in products and foods with high phytoestrogen content. However, phytoestrogens may as well have adverse estrogenicity related effects similar to any estrogen. Therefore, the assessment of estrogenic potency of dietary compounds is of critical importance. Due to the complex nature of estrogenicity, no single comprehensive test approach is available. Instead, several in vitro and in vivo assays are applied to evaluate estrogenic potency. In vitro estrogen receptor (ER) binding assays provide information on the ability of the compound to I) interact with ERs, II) bind to estrogen responsive element on promoter of the target gene as ligand-ER complex, and III) interact between the co-activator and ERs in ligand-dependent manner. In addition, transactivation assays in cells screen for ligand-induced ERmediated gene activation. Biochemical in vitro analysis can be used to test for possible effects on protein activities and E-screen assays to measure (anti)proliferative response in estrogen responsive cells. However, for assessment of estrogenicity in organs and tissues, in vivo approaches are essential. In females, the uterotrophic assay is applicable for testing ERa agonistic and antagonistic dietary compounds in immature or adult ovariectomized animals. In addition, mammary gland targeted estrogenicity can be detected as stimulated ductal elongation and altered formation of terminal end buds in immature or peripubertal animals. In males, Hershberger assay in peri-pubertal castrated rats can be used to detect (anti)androgenic/ (anti)estrogenic responses in accessory sex glands and other hormone regulated tissues. In addition to these short-term assays, sub-acute and chronic reproductive toxicity assays as well as two-generation studies can be applied for phytoestrogens to confirm their safety in long-term use. For reliable assessment of estrogenicity of dietary phytoestrogens in vivo, special emphasis should be focused on selection of the basal diet, route and doses of administration, and possible metabolic differences between the species used and humans. In conclusion, further development and standardization of the estrogenicity test methods are needed for better interpretation of both the potential benefits and risks of increasing consumption of phytoestrogens from diets and supplements.
Collapse
|
13
|
Rotoli SM, Biswas-Fiss E, Biswas SB. Quantitative analysis of the mechanism of DNA binding by Bacillus DnaA protein. Biochimie 2012; 94:2764-75. [PMID: 22974984 DOI: 10.1016/j.biochi.2012.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 08/30/2012] [Indexed: 11/29/2022]
Abstract
DnaA protein has the sole responsibility of initiating a new round of DNA replication in prokaryotic organisms. It recognizes the origin of DNA replication, and initiates chromosomal DNA replication in the bacterial genome. In Gram-negative Escherichia coli, a large number of DnaA molecules bind to specific DNA sequences (known as DnaA boxes) in the origin of DNA replication, oriC, leading to the activation of the origin. We have cloned, expressed, and purified full-length DnaA protein in large quantity from Gram-positive pathogen Bacillus anthracis (DnaA(BA)). DnaA(BA) was a highly soluble monomeric protein making it amenable to quantitative analysis of its origin recognition mechanisms. DnaA(BA) bound DnaA boxes with widely divergent affinities in sequence and ATP-dependent manner. In the presence of ATP, the K(D) ranged from 3.8 × 10(-8) M for a specific DnaA box sequence to 4.1 × 10(-7) M for a non-specific DNA sequence and decreased significantly in the presence of ADP. Thermodynamic analyses of temperature and salt dependence of DNA binding indicated that hydrophobic (entropic) and ionic bonds contributed to the DnaA(BA)·DNA complex formation. DnaA(BA) had a DNA-dependent ATPase activity. DNA sequences acted as positive effectors and modulated the rate (V(max)) of ATP hydrolysis without any significant change in ATP binding affinity.
Collapse
Affiliation(s)
- Shawna M Rotoli
- Department of Molecular Biology, Graduate School of Biomedical Sciences, University of Medicine & Dentistry of New Jersey, 2 Medical Center Drive, Stratford, NJ 08084, USA
| | | | | |
Collapse
|
14
|
Moody AD, Miura MT, Connaghan KD, Bain DL. Thermodynamic dissection of estrogen receptor-promoter interactions reveals that steroid receptors differentially partition their self-association and promoter binding energetics. Biochemistry 2012; 51:739-49. [PMID: 22201220 DOI: 10.1021/bi2017156] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Steroid receptors define a family of ligand-activated transcription factors. Recent work has demonstrated that the receptors regulate distinct but overlapping gene networks, yet the mechanisms by which they do so remain unclear. We previously determined the microscopic binding energetics for progesterone receptor (PR) isoform assembly at promoters containing multiple response elements. We found that the two isoforms (PR-A and PR-B) share nearly identical dimerization and intrinsic DNA binding free energies but maintain large differences in cooperative free energy. Moreover, cooperativity can be modulated by monovalent ion binding and promoter layout, suggesting that differences in cooperativity might control isoform-specific promoter occupancy and thus receptor function. To determine whether cooperative binding energetics are common to other members of the steroid receptor family, we dissected the thermodynamics of estrogen receptor-α (ER-α):promoter interactions. We find that the ER-α intrinsic DNA binding free energy is identical to that of the PR isoforms. This was expected, noting that receptor DNA binding domains are highly conserved. Unexpectedly, ER-α generates negligible cooperativity-orders of magnitude less than predicted based on our studies of the PR isoforms. However, analysis of the cooperativity term suggests that it reflects a balance between highly favorable cooperative stabilization and unfavorable promoter bending. Moreover, ER-α cooperative free energy is compensated for by a large increase in dimerization free energy. Collectively, the results demonstrate that steroid receptors differentially partition not only cooperative energetics but also dimerization energetics. We speculate that this ability serves as a framework for regulating receptor-specific promoter occupancy and thus receptor-specific gene regulation.
Collapse
Affiliation(s)
- Amie D Moody
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | | | | | | |
Collapse
|
15
|
Lin PH, Chen RH, Lee CH, Chang Y, Chen CS, Chen WY. Studies of the binding mechanism between aptamers and thrombin by circular dichroism, surface plasmon resonance and isothermal titration calorimetry. Colloids Surf B Biointerfaces 2011; 88:552-8. [PMID: 21885262 DOI: 10.1016/j.colsurfb.2011.07.032] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/12/2011] [Accepted: 07/15/2011] [Indexed: 10/17/2022]
Abstract
Thrombin, a multifunctional serine protease, has both procoagulant and anticoagulant functions in human blood. Thrombin has two electropositive exosites. One is the fibrinogen-binding site and the other is the heparin-binding site. Over the past decade, two thrombin-binding aptamers (15-mer and 29-mer) were reported by SELEX technique. Recently, many studies examined the interactions between the 15-mer aptamer and thrombin extensively, but the data on the difference of these two aptamers binding to thrombin are still lacking and worth investigating for fundamental understanding. In the present study, we combined conformational data from circular dichroism (CD), kinetics and thermodynamics information from surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) to compare the binding mechanism between the two aptamers with thrombin. Special attentions were paid to the formation of G-quadruplex and the effects of ions on the aptamer conformation on the binding and the kinetics discrimination between specific and nonspecific interactions of the binding. The results indicated reasonably that the 15-mer aptamer bound to fibrinogen-binding site of thrombin using a G-quadruplex structure and was dominated by electrostatic interactions, while the 29-mer aptamer bound to heparin-binding site thrombin using a duplex structure and was driven mainly by hydrophobic effects.
Collapse
Affiliation(s)
- Po-Hsun Lin
- Institute of Systems Biology and Bioinformatics, National Central University, Jhong-Li, 320 Taiwan
| | | | | | | | | | | |
Collapse
|
16
|
Mutagenesis-based evidence for an asymmetric configuration of the ring-shaped transcription termination factor Rho. J Mol Biol 2010; 405:497-518. [PMID: 21059356 DOI: 10.1016/j.jmb.2010.11.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 09/16/2010] [Accepted: 11/01/2010] [Indexed: 11/20/2022]
Abstract
Transcription termination factor Rho is an ATP-dependent ring-shaped molecular motor that tracks along RNA to dissociate RNA-DNA duplexes and transcription complexes in its path. The Rho hexamer contains two distinct sites for interaction with RNA. The primary binding site is composed of pyrimidine-specific binding clefts that are located in the N-terminal domains and anchor Rho to transcripts at C-rich Rut (Rho utilization) sites. Components of the secondary binding site (SBS) in the C-terminal domains directly couple RNA binding to ATP hydrolysis in order to translocate RNA through the Rho ring. Published crystal structures of RNA-bound Rho display distinct architectures ('trimer-of-dimers' or asymmetric hexamer) and SBS-RNA interaction networks that suggested conflicting models of RNA "handoff" or "escort" by the Rho subunits. To probe the mechanism of mechanochemical transduction in Rho, we have mutated into alanines (or glycines) the residues that make SBS contacts with RNA in the 'trimer-of-dimers' structure supporting the "handoff" model. We find that the resulting single-point mutants have similar RNA binding affinities but exhibit significantly different ATP hydrolysis, transcription termination, and RNA-DNA unwinding activities that are more compatible with the asymmetric Rho structure than with the 'trimer-of-dimers' structure and the resulting "handoff" model. We discuss our findings in connection with specific features of the asymmetric Rho structure yet argue that a simple RNA "escort" model is insufficient to account for all experimental evidence.
Collapse
|
17
|
Control of vitellogenin genes expression by sequences derived from transposable elements in rainbow trout. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:546-54. [DOI: 10.1016/j.bbagrm.2010.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 07/05/2010] [Accepted: 07/09/2010] [Indexed: 01/24/2023]
|
18
|
Jantz D, Berg JM. Probing the DNA-binding affinity and specificity of designed zinc finger proteins. Biophys J 2010; 98:852-60. [PMID: 20197039 DOI: 10.1016/j.bpj.2009.11.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 10/30/2009] [Accepted: 11/02/2009] [Indexed: 11/17/2022] Open
Abstract
Engineered transcription factors and endonucleases based on designed Cys(2)His(2) zinc finger domains have proven to be effective tools for the directed regulation and modification of genes. The introduction of this technology into both research and clinical settings necessitates the development of rapid and accurate means of evaluating both the binding affinity and binding specificity of designed zinc finger domains. Using a fluorescence anisotropy-based DNA-binding assay, we examined the DNA-binding properties of two engineered zinc finger proteins that differ by a single amino acid. We demonstrate that the protein with the highest affinity for a particular DNA site need not be the protein that binds that site with the highest degree of specificity. Moreover, by comparing the binding characteristics of the two proteins at varying salt concentrations, we show that the ionic strength makes significant and variable contributions to both affinity and specificity. These results have significant implications for zinc finger design as they highlight the importance of considering affinity, specificity, and environmental requirements in designing a DNA-binding domain for a particular application.
Collapse
Affiliation(s)
- Derek Jantz
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | | |
Collapse
|
19
|
Krusiński T, Ożyhar A, Dobryszycki P. Dual FRET assay for detecting receptor protein interaction with DNA. Nucleic Acids Res 2010; 38:e108. [PMID: 20139421 PMCID: PMC2875001 DOI: 10.1093/nar/gkq049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 01/15/2010] [Accepted: 01/18/2010] [Indexed: 01/17/2023] Open
Abstract
We present here a new assay that is based on the idea of the molecular beacon. This assay makes it possible to investigate two proteins interacting with DNA at two binding sites that are close to each other. The effectiveness of the test depends on the exclusive binding of three DNA fragments in the presence of two proteins, and the monitoring of the process depends upon observing the quenching of two independent fluorescence donors. As a model we used the components of the heterodimeric ecdysteroid receptor proteins ultraspiracle (Usp) and ecdysone receptor (EcR) from Drosophila melanogaster and a response element from the promoter of the hsp27 gene. The response element consists of two binding sites (half-sites) for the DNA binding domains (DBDs). We have shown that protein-protein interactions mediate cooperative binding of the ecdysteroid receptor DBDs to a hsp27(pal) response element. The analysis of the microscopic dissociation constants obtained with the DMB led to the conclusion that there was increased affinity of UspDBD to the 5' half-site in the presence of EcRDBD when the 3' half-site was occupied, and increased affinity of EcRDBD to the 3' half-site when the 5' half-site was occupied.
Collapse
Affiliation(s)
| | | | - Piotr Dobryszycki
- Wroclaw University of Technology, Faculty of Chemistry, Division of Biochemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| |
Collapse
|
20
|
Biswas-Fiss EE, Kurpad DS, Joshi K, Biswas SB. Interaction of extracellular domain 2 of the human retina-specific ATP-binding cassette transporter (ABCA4) with all-trans-retinal. J Biol Chem 2010; 285:19372-83. [PMID: 20404325 DOI: 10.1074/jbc.m110.112896] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The retina-specific ATP-binding cassette (ABC) transporter, ABCA4, is essential for transport of all-trans-retinal from the rod outer segment discs in the retina and is associated with a broad range of inherited retinal diseases, including Stargardt disease, autosomal recessive cone rod dystrophy, and fundus flavimaculatus. A unique feature of the ABCA subfamily of ABC transporters is the presence of highly conserved, long extracellular loops or domains (ECDs) with unknown function. The high degree of sequence conservation and mapped disease-associated mutations in these domains suggests an important physiological significance. Conformational analysis using CD spectroscopy of purified, recombinant ECD2 protein demonstrated that it has an ordered and stable structure composed of 27 +/- 3% alpha-helix, 20 +/- 3% beta-pleated sheet, and 53 +/- 3% coil. Significant conformational changes were observed in disease-associated mutant proteins. Using intrinsic tryptophan fluorescence emission spectrum of ECD2 polypeptide and fluorescence anisotropy, we have demonstrated that this domain specifically interacts with all-trans-retinal. Furthermore, the retinal interaction appeared preferential for the all-trans-isomer and was directly measurable through fluorescence anisotropy analysis. Our results demonstrate that the three macular degeneration-associated mutations lead to significant changes in the secondary structure of the ECD2 domain of ABCA4, as well as in its interaction with all-trans-retinal.
Collapse
Affiliation(s)
- Esther E Biswas-Fiss
- Department of Bioscience Technologies, Jefferson School of Health Professions, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
| | | | | | | |
Collapse
|
21
|
Savatier J, Jalaguier S, Ferguson ML, Cavaillès V, Royer CA. Estrogen receptor interactions and dynamics monitored in live cells by fluorescence cross-correlation spectroscopy. Biochemistry 2010; 49:772-81. [PMID: 20039662 DOI: 10.1021/bi9013006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Quantitative characterization of protein interactions in live cells remains one of the most important challenges in modern biology. In the present work we have used two-photon, two-color, fluorescence cross-correlation spectroscopy (FCCS) in transiently transfected COS-7 cells to measure the concentrations and interactions of estrogen receptor (ER) subtypes alpha and beta with one of their transcriptional coactivator proteins, TIF2, as well as heterodimerization between the two ER subtypes. Using this approach in a systematic fashion, we observed a strong ligand-dependent modulation of receptor-coactivator complexation, as well as strong protein concentration dependence for complex formation in the absence of ligand. These quantitative values for protein and complex concentrations provide the first estimates for the ER-TIF2 K(d) for the full-length proteins and in a cellular context (agonist, < approximately 6 nM; antagonist, > approximately 3 microM; unliganded, approximately 200 nM). Coexpression of the two ER subtypes revealed substantial receptor heterodimer formation. They also provide, for the first time, estimated homo- and heterodimerization constants found to be similar and in the low nanomolar range. These results underscore the importance of receptor and coregulator expression levels and stability in the tissue-dependent modulation of receptor function under normal and pathological conditions.
Collapse
Affiliation(s)
- Julien Savatier
- Centre de Biochimie Structurale, INSERM U554, and CNRS UMR5048, Université Montpellier 1 and 2, Montpellier F-34090, France
| | | | | | | | | |
Collapse
|
22
|
Figueira ACM, Lima LMTR, Lima LHF, Ranzani AT, Mule GDS, Polikarpov I. Recognition by the thyroid hormone receptor of canonical DNA response elements. Biochemistry 2010; 49:893-904. [PMID: 20025240 DOI: 10.1021/bi901282s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To shed more light on the molecular requirements for recognition of thyroid response elements (TREs) by thyroid receptors (TRs), we compared the specific aspects of DNA TRE recognition by different TR constructs. Using fluorescence anisotropy, we performed a detailed and hierarchical study of TR-TRE binding. This was done by comparing the binding affinities of three different TR constructs for four different TRE DNA elements, including palindromic sequences and direct repeats (F2, PAL, DR-1, and DR-4) as well as their interactions with nonspecific DNA sequences. The effect of MgCl(2) on suppressing of nonselective DNA binding to TR was also investigated. Furthermore, we determined the dissociation constants of the hTRbeta DBD (DNA binding domain) and hTRbeta DBD-LBD (DNA binding and ligand binding domains) for specific TREs. We found that a minimum DNA recognition peptide derived from DBD (H1TR) is sufficient for recognition and interaction with TREs, whereas scrambled DNA sequences were unrecognized. Additionally, we determined that the TR DBD binds to F2, PAL, and DR-4 with high affinity and similar K(d) values. The TR DBD-LBD recognizes all the tested TREs but binds preferentially to F2, with even higher affinity. Finally, our results demonstrate the important role played by LBDs in modulating TR-DNA binding.
Collapse
Affiliation(s)
- Ana Carolina Migliorini Figueira
- Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Av. Trabalhador Saocarlense, 400, Sao Carlos, SP, Brazil 13560-970
| | | | | | | | | | | |
Collapse
|
23
|
Tan YN, Su X, Liu ET, Thomsen JS. Gold-Nanoparticle-Based Assay for Instantaneous Detection of Nuclear Hormone Receptor−Response Elements Interactions. Anal Chem 2010; 82:2759-65. [DOI: 10.1021/ac9026498] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yen Nee Tan
- Institute of Material Research and Engineering, ASTAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, and Genome Institute of Singapore, ASTAR (Agency for Science, Technology and Research), 60 Biopolis Street, Singapore 138672
| | - Xiaodi Su
- Institute of Material Research and Engineering, ASTAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, and Genome Institute of Singapore, ASTAR (Agency for Science, Technology and Research), 60 Biopolis Street, Singapore 138672
| | - Edison T. Liu
- Institute of Material Research and Engineering, ASTAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, and Genome Institute of Singapore, ASTAR (Agency for Science, Technology and Research), 60 Biopolis Street, Singapore 138672
| | - Jane S. Thomsen
- Institute of Material Research and Engineering, ASTAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, and Genome Institute of Singapore, ASTAR (Agency for Science, Technology and Research), 60 Biopolis Street, Singapore 138672
| |
Collapse
|
24
|
Neo SJ, Su X, Thomsen JS. Surface plasmon resonance study of cooperative interactions of estrogen receptor alpha and transcriptional factor Sp1 with composite DNA elements. Anal Chem 2009; 81:3344-9. [PMID: 19331400 DOI: 10.1021/ac802543x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have applied surface plasmon resonance (SPR) spectroscopy to study the cooperative interactions of estrogen receptor alpha (ERalpha) and transcription factor Sp1 with a composite DNA element, containing an estrogen response element (ERE) half-site upstream of two adjacent Sp1 sites (+571 ERE/Sp1 composite site in promoter A of the human PR gene). Using nuclear extracts of MCF-7 breast cancer cells as sample, we have shown that Sp1 is associated with Sp1-binding sites only, whereas ERalpha can be recruited to DNA both through direct binding to the ERE half-site and/or through protein-protein interactions with DNA-bound Sp1. The ERE half-site and the proximal Sp1 site are only 4 bp apart, and our data suggests that one transcription factor bound to DNA constitutes a sterical hindrance of the accessibility of the binding site for the other transcription factor. Our data confirms previous observations that ERalpha increases the amount of Sp1 recruited to the composite binding site in a dose-dependent manner. Using recombinant proteins, we have unambiguously proved the formation of a ternary complex of ERalpha/Sp1-composite DNA, for which previously published electrophoretic mobility shift assay (EMSA) results are contradictive. With this study, we have demonstrated that the solid-liquid-phase SPR assay is a powerful alternative for studying multiprotein-DNA interactions and is superior to the EMSA experiments as it is capable of real-time measurements, can quantify the amount of protein bound, and can capture transient and weak binding interactions. The comprehensive characterization of the synergistic interactions between ERalpha-DNA, Sp1-DNA, and ERalpha-Sp1 contributes to the understanding of how ERalpha and Sp1 influence and activate gene transcription.
Collapse
Affiliation(s)
- Siew Jun Neo
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 3 Research Link, Singapore 117602
| | | | | |
Collapse
|
25
|
|
26
|
LiCata VJ, Wowor AJ. Applications of Fluorescence Anisotropy to the Study of Protein–DNA Interactions. Methods Cell Biol 2008; 84:243-62. [DOI: 10.1016/s0091-679x(07)84009-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
27
|
Equilibrium analysis of the DNA binding domain of the ultraspiracle protein interaction with the response element from the hsp27 gene promoter--the application of molecular beacon technology. J Fluoresc 2007; 18:1-10. [PMID: 18049881 DOI: 10.1007/s10895-007-0285-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 11/12/2007] [Indexed: 10/22/2022]
Abstract
Ecdysteroids initiate molting and metamorphosis in insects via a receptor which belongs to the superfamily of nuclear receptors. The ecdysone receptor consists of two proteins: the ecdysone receptor (EcR) and the ultraspiracle (Usp). The EcR-Usp dimer conducts transcription through a hsp27(pal) response element. Usp acts as an anchor orienting the whole complex on the DNA. The molecular beacon methodology was applied to detect the sequence-specific DNA of a natural hsp27 (pal) or mutated protein interaction with the DNA binding domain from the Usp. The dissociation constant, K(d), of the UspDBD-hsp27 (pal) complex was determined to be 1.42+/-0.48 nM, whereas K(d) for UspDBD(DeltaA)-hsp27(pal) was 6.6+/-0.5 nM. Mutation of Val-71 for Ala blocks formation of the protein-DNA complex in contrast to Glu-19 mutation for Ala for which K(d)=4.31+/-1.01 nM. The results obtained with the molecular beacon technology are related to those obtained by fluorescence anisotropy titrations.
Collapse
|
28
|
Determination of estrogen presence in water by SPR using estrogen receptor dimerization. Anal Bioanal Chem 2007; 390:873-83. [DOI: 10.1007/s00216-007-1725-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 09/26/2007] [Accepted: 10/25/2007] [Indexed: 10/22/2022]
|
29
|
Peh WYX, Reimhult E, Teh HF, Thomsen JS, Su X. Understanding ligand binding effects on the conformation of estrogen receptor alpha-DNA complexes: a combinational quartz crystal microbalance with dissipation and surface plasmon resonance study. Biophys J 2007; 92:4415-23. [PMID: 17384075 PMCID: PMC1877774 DOI: 10.1529/biophysj.106.099382] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Estrogen receptors are ligand-activated transcription factors that regulate gene expression by binding to specific DNA sequences. To date, the effect of ligands on the conformation of estrogen receptor alpha (ERalpha)-DNA complex remains a poorly understood issue. In our study, we are introducing the quartz crystal microbalance with dissipation monitoring (QCM-D) as a new alternative to study the conformational differences in protein-DNA complexes. Specifically, we have used QCM-D, in combination with surface plasmon resonance (SPR) spectroscopy, to monitor the binding of ERalpha to a specific DNA (estrogen response element, ERE) and a nonspecific DNA in the presence of either the agonist ligand, 17b-estradiol, the partial antagonist ligand, 4-hydroxytamoxifen, or vehicle alone. Both with presence and absence of ligand, the specific ERalpha-ERE complexes are observed to adopt a more compact conformation compared to nonspecific complexes. This observation is well correlated to the biophysical changes occurring during protein-DNA interaction shown by past structural and mechanism studies. Notably, pretreatment of ERalpha with E2 and 4OHT affects not only the viscoelasticity and conformation of the protein-DNA complex but also ERalpha binding capacity to immobilized ERE. These results affirm that ligands have remarkable effects on ERalpha-DNA complexes. Understanding these effects will provide insight into how ligand binding promotes subsequent events required for gene transcription.
Collapse
Affiliation(s)
- Wendy Y X Peh
- Institute of Materials Research and Engineering, Singapore 117602
| | | | | | | | | |
Collapse
|
30
|
Furukawa T, Bai CX, Kaihara A, Ozaki E, Kawano T, Nakaya Y, Awais M, Sato M, Umezawa Y, Kurokawa J. Ginsenoside Re, a main phytosterol of Panax ginseng, activates cardiac potassium channels via a nongenomic pathway of sex hormones. Mol Pharmacol 2006; 70:1916-24. [PMID: 16985185 DOI: 10.1124/mol.106.028134] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ginseng root is one of the most popular herbs throughout the world and is believed to be a panacea and to promote longevity. It has been used as a medicine to protect against cardiac ischemia, a major cause of death in the West. We have previously demonstrated that ginsenoside Re, a main phytosterol of Panax ginseng, inhibits Ca(2+) accumulation in mitochondria during cardiac ischemia/reperfusion, which is attributable to nitric oxide (NO)-induced Ca(2+) channel inhibition and K(+) channel activation in cardiac myocytes. In this study, we provide compelling evidence that ginsenoside Re activates endothelial NO synthase (eNOS) to release NO, resulting in activation of the slowly activating delayed rectifier K(+) current. The eNOS activation occurs via a nongenomic pathway of each of androgen receptor, estrogen receptor-alpha, and progesterone receptor, in which c-Src, phosphoinositide 3-kinase, Akt, and eNOS are sequentially activated. However, ginsenoside Re does not stimulate proliferation of androgen-responsive LNCaP cells and estrogen-responsive MCF-7 cells, implying that ginsenoside Re does not activate a genomic pathway of sex hormone receptors. Fluorescence resonance energy transfer experiments with a probe, SCCoR (single cell coactivator recruitment), indicate that the lack of genomic action is attributable to failure of coactivator recruitment. Thus, ginsenoside Re acts as a specific agonist for the nongenomic pathway of sex steroid receptors, and NO released from activated eNOS underlies cardiac K(+) channel activation and protection against ischemia-reperfusion injury.
Collapse
Affiliation(s)
- Tetsushi Furukawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Su X, Lin CY, O'Shea SJ, Teh HF, Peh WYX, Thomsen JS. Combinational Application of Surface Plasmon Resonance Spectroscopy and Quartz Crystal Microbalance for Studying Nuclear Hormone Receptor−Response Element Interactions. Anal Chem 2006; 78:5552-8. [PMID: 16878895 DOI: 10.1021/ac0606103] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conventional methodologies for studying protein-DNA complexes, such as electrophoretic mobility shift assays (EMSAs), lack the real-time sensitivity and precision to accurately characterize the complex dynamics of interactions between transcription factors and their binding sites. To better understand the interactions between estrogen receptor (ER) subtypes and the estrogen response elements (EREs), we employed surface plasmon resonance (SPR) spectroscopy and quartz crystal microbalance with dissipation measurement (QCM-D) and made the following observations: (1) base substitutions in ERE half-sites reduced binding affinity for both ERalpha and ERbeta, (2) ERalpha has a higher sequence specificity than ERbeta or there were more nonspecific interactions between ERbeta and control DNA, and (3) ERalpha bound ERE as dimers and ERbeta bound as tetramers. These findings highlight intrinsic differences in DNA-binding properties between receptor subtypes, which are not apparent based on the high degree of conservation (96% identity) in their DNA-binding domains and results from EMSA studies. With this study, we demonstrate the potential of utilizing SPR and QCM in combination for a comprehensive characterization of ER-DNA interactions, including sequence-dependent binding mechanisms and structural differences in ERalpha-DNA and ERbeta-DNA complexes.
Collapse
Affiliation(s)
- Xiaodi Su
- Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602.
| | | | | | | | | | | |
Collapse
|
32
|
Heneghan AF, Connaghan-Jones KD, Miura MT, Bain DL. Cooperative DNA binding by the B-isoform of human progesterone receptor: thermodynamic analysis reveals strongly favorable and unfavorable contributions to assembly. Biochemistry 2006; 45:3285-96. [PMID: 16519523 PMCID: PMC2505112 DOI: 10.1021/bi052046g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Progesterone receptors (PR) play critical roles in eukaryotic gene regulation, yet the mechanisms by which they assemble at multisite promoters are poorly understood. Here we present a thermodynamic analysis of the interactions of the PR B-isoform (PR-B) with promoters containing either one or two progesterone response elements (PREs). Utilizing quantitative footprinting, we have resolved the microscopic energetics of PR-B binding, including cooperativity terms. The results of this analysis challenge a number of assumptions found in traditional models of receptor function. First, PR-B interactions at a single PRE can be equally well described by mechanisms invoking either the receptor monomer or the dimer as the active DNA binding species. If, as is commonly accepted, PR-B interacts with response elements only as a preformed dimer, then its intrinsic binding affinity is not the typically observed nanomolar but is rather picomolar. This high affinity binding is opposed, however, by a large energetic penalty. The penalty presumably pays for costly structural rearrangements of the receptor dimer and/or response element that are needed to form the protein-DNA complex. If PR-B assembles at a single response element via successive monomer binding reactions, then this penalty minimizes cooperative interactions between adjacent monomers. When binding to two response elements, the receptor exhibits strong intersite cooperativity. Although this phenomenon has been observed before, the present work demonstrates that the energetics reach levels seen in highly cooperative systems such as lambda cI repressor. This first quantitative dissection of cooperative receptor-promoter interactions suggests that PR-B function is more complex than traditionally envisioned.
Collapse
Affiliation(s)
- Aaron F Heneghan
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, 4200 East 9th Avenue, Denver, Colorado 80262, USA
| | | | | | | |
Collapse
|
33
|
Morozov AV, Havranek JJ, Baker D, Siggia ED. Protein-DNA binding specificity predictions with structural models. Nucleic Acids Res 2005; 33:5781-98. [PMID: 16246914 PMCID: PMC1270944 DOI: 10.1093/nar/gki875] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Protein-DNA interactions play a central role in transcriptional regulation and other biological processes. Investigating the mechanism of binding affinity and specificity in protein-DNA complexes is thus an important goal. Here we develop a simple physical energy function, which uses electrostatics, solvation, hydrogen bonds and atom-packing terms to model direct readout and sequence-specific DNA conformational energy to model indirect readout of DNA sequence by the bound protein. The predictive capability of the model is tested against another model based only on the knowledge of the consensus sequence and the number of contacts between amino acids and DNA bases. Both models are used to carry out predictions of protein-DNA binding affinities which are then compared with experimental measurements. The nearly additive nature of protein-DNA interaction energies in our model allows us to construct position-specific weight matrices by computing base pair probabilities independently for each position in the binding site. Our approach is less data intensive than knowledge-based models of protein-DNA interactions, and is not limited to any specific family of transcription factors. However, native structures of protein-DNA complexes or their close homologs are required as input to the model. Use of homology modeling can significantly increase the extent of our approach, making it a useful tool for studying regulatory pathways in many organisms and cell types.
Collapse
Affiliation(s)
- Alexandre V Morozov
- Center for Studies in Physics and Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
| | | | | | | |
Collapse
|
34
|
Bourdoncle A, Labesse G, Margueron R, Castet A, Cavaillès V, Royer CA. The Nuclear Receptor Coactivator PGC-1α Exhibits Modes of Interaction with the Estrogen Receptor Distinct From those of SRC-1. J Mol Biol 2005; 347:921-34. [PMID: 15784253 DOI: 10.1016/j.jmb.2005.01.048] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 01/19/2005] [Accepted: 01/20/2005] [Indexed: 11/29/2022]
Abstract
Estrogen receptor (ER) function is mediated by multi-domain co-regulator proteins. A fluorescently labelled fragment of the human PGC-1alpha co-regulator (residues 91-408) bearing the two motifs most strongly implicated in interactions with nuclear receptors (NR box2 and NR box3), was used to characterize in vitro binding of PGC-1alpha to ER. Anisotropy measurements revealed that the affinity of this PGC-1alpha fragment for human ERalpha and beta was fairly strong in the presence of estradiol (approximately 5 nM), and that unlike a similar fragment of SRC-1 (570-780), PGC-191-408 exhibited ligand-independent interactions with ER, particularly with ERbeta (Kd approximately 30 nM). Competition experiments of the complex between ERalpha and fluorescently labelled PGC-1 91-408 with unlabelled SRC-1 570-780 showed that PGC-1 91-408 was an efficient competitor of SRC-1 570-780, while the inverse was not true, underscoring their distinct modes of binding. The anisotropy data provide strong evidence for a ternary complex between ERalpha, SRC-1 570-780 and PGC-1 91-408. GST-pull-down experiments with deletion mutants of ERalpha revealed that the constitutive binding of PGC-1 91-408 requires the presence of the linker domain between the DNA binding and ligand binding domains (DBD and LBD). Homology modeling studies of the different regions of full length PGC-1alpha confirmed the lack of compact tertiary structure of the N-terminal region bearing the NR box motifs, and suggested a slightly different mode of interaction compared to the NR box motifs of SRC-1. They also provided reasonable structural models for the coiled-coil dimerization motif at residues 633-675, as well as the C-terminal putative RNA binding domain, raising important questions concerning the stoichiometry of its complex with the nuclear receptors.
Collapse
Affiliation(s)
- Anne Bourdoncle
- INSERM U554 Centre de Biochimie Structurale, 29 rue de Navacelles 34090, Montpellier Cedex, France.
| | | | | | | | | | | |
Collapse
|
35
|
Wang SY, Ahn BS, Harris R, Nordeen SK, Shapiro DJ. Fluorescence anisotropy microplate assay for analysis of steroid receptor-DNA interactions. Biotechniques 2005; 37:807-8, 810-7. [PMID: 15560136 DOI: 10.2144/04375rr01] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To analyze the interactions of steroid/nuclear hormone receptors with their DNA response elements, we used ultra low-volume microplates to develop a simple and rapid fluorescence anisotropy assay. The novel fluorescence anisotropy microplate assay (FAMA) was applied to the binding of estrogen and progesterone receptors (ER and PR, respectively) to their respective DNA response elements. The FAMA offers exceptional flexibility in its ability to test a variety of binding conditions and DNA response elements in real time. This assay can differentiate between, and quantitate, sequence-specific and nonspecific binding of receptors to DNA and offers the possibility of true solution analysis of the interaction of coregulators with the estrogen response element (ERE)-ER complex. To test suitability for screening large compound libraries, we demonstrated that the FAMA generates stable signals for more than 4 hours, is insensitive to inhibition by dimethyl sulfoxide (DMSO), and works well in 384-well plates. We analyzed inhibition of receptor-DNA interaction by several zinc chelators and demonstrated zinc dependence and a generally higher sensitivity to inhibition for PR-progesterone response element (PRE) interactions than for ER-ERE interactions. The FAMA is the first system suitable for screening large compound libraries to identify novel compounds that antagonize (or stimulate) binding of steroid receptors to their DNA response elements.
Collapse
|
36
|
Lima LMTR, Silva JL. Positive contribution of hydration on DNA binding by E2c protein from papillomavirus. J Biol Chem 2004; 279:47968-74. [PMID: 15361525 DOI: 10.1074/jbc.m407696200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Protein-nucleic acid interactions are responsible for the regulation of key biological events such as genomic transcription and recombination and viral replication. However, the recognition mechanisms involved in these processes are not completely understood. Here, we investigate the dominant forces involved in protein-protein and protein-DNA interactions for the 80-amino-acid C-terminal domain of the E2 protein (E2c) from human papillomavirus (HPV-16). The E2c protein is a homodimer that specifically binds to double-stranded DNA containing the consensus sequence ACCG-N(4)-CGGT, where N is any nucleotide. DNA binding affinity is reduced by lowering water chemical potential, accompanied by an increase in cooperativity. Wyman linkage relations between affinity and water chemical potential indicate that 11 additional water molecules are bound in the formation of the complex between E2c and DNA. Salt dissociation isotherms showed that 10 counterions are released upon association, even at low water activity, indicating that this latter variable does not change the electrostatic component of the interaction. Further analysis demonstrates a strong dependence of cooperativity of binding on the protein concentration. Altogether, these results reveal a novel binding pathway in which the consolidated complex may achieve its final form via a monomer-DNA intermediate, which favors the binding of a second monomer. This molecular mechanism reveals the contributions of multiple conformers in a tight virus genome modulation that seems to be important in the cell infection scenario.
Collapse
Affiliation(s)
- Luis Maurício T R Lima
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, Bss34, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil.
| | | |
Collapse
|
37
|
Biswas SB, Flowers S, Biswas-Fiss EE. Quantitative analysis of nucleotide modulation of DNA binding by DnaC protein of Escherichia coli. Biochem J 2004; 379:553-62. [PMID: 14715083 PMCID: PMC1224104 DOI: 10.1042/bj20031255] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Revised: 12/20/2003] [Accepted: 01/09/2004] [Indexed: 11/17/2022]
Abstract
In this study, we have presented the first report of Escherichia coli DnaC protein binding to ssDNA (single stranded DNA) in an apparent hexameric form. DnaC protein transfers DnaB helicase onto a nascent chromosomal DNA replication fork at oriC, the origin of E. coli DNA replication. In eukaryotes, Cdc6 protein may play a similar role in the DNA helicase loading in the replication fork during replication initiation at the origin. We have analysed the DNA-binding properties of DnaC protein and a quantitative analysis of the nucleotide regulation of DnaC-DNA and DnaC-DnaB interactions using fluorescence anisotropy and affinity sensor analysis. DnaC protein bound to ssDNA with low to moderate affinity and the affinity was strictly modulated by nucleotides. DnaC bound ssDNA in the complete absence of nucleotides. The DNA-binding affinity was significantly increased in the presence of ATP, but not ATP[S]. In the presence of ADP, the binding affinity decreased approximately fifty-fold. Both anisotropy and biosensor analyses demonstrated that with DnaC protein, ATP facilitated ssDNA binding, whereas ADP facilitated its dissociation from ssDNA, which is a characteristic of an ATP/ADP switch. Both ssDNA and nucleotides modulate DnaB6*DnaC6 complex formation, which has significant implications in DnaC protein function. Based on the thermodynamic data provided in this study, we have proposed a mechanism of DnaB loading on to ssDNA by DnaC protein.
Collapse
Affiliation(s)
- Subhasis B Biswas
- Department of Molecular Biology, School of Medicine, Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Stratford, NJ 08084, USA.
| | | | | |
Collapse
|
38
|
Margeat E, Bourdoncle A, Margueron R, Poujol N, Cavaillès V, Royer C. Ligands differentially modulate the protein interactions of the human estrogen receptors alpha and beta. J Mol Biol 2003; 326:77-92. [PMID: 12547192 DOI: 10.1016/s0022-2836(02)01355-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The interactions of human estrogen receptor subtypes ERalpha and ERbeta with DNA and a 210 amino acid residue fragment of the coactivator protein SRC-1 bearing three nuclear receptor interaction motifs were investigated quantitatively using fluorescence anisotropy in the presence of agonist and antagonist ligands. ERalpha and ERbeta were found to bind in a similar manner to DNA, and both salt and temperature affected the affinity and/or stoichiometry of these interactions. The agonist ligands estradiol, estrone and estriol did not modify the binding of ERalpha to the fluorescein-labeled target estrogen response element. However, in the case of ERbeta, these ligands led to the formation of some higher-order protein-DNA complexes and a small decrease in affinity. The partial agonist 4-hydroxytamoxifen had little effect on either ER subtype, whereas the pure antagonist ICI 182,780 led to the cooperative formation of protein-DNA complexes of higher order than dimer, as further demonstrated by competition experiments and gel mobility-shift assays. In addition to DNA binding, the interaction of both ER subtypes with the Alexa488-labeled SRC-1 coactivator fragment was investigated by fluorescence anisotropy. The agonist ligands estrone, estradiol, estriol, genistein and ethynyl estradiol exhibited distinct capacities for inducing the recruitment of SRC-1 that were not correlated with their affinity for the receptor. Moreover, estrone and genistein exhibited subtype specificity in that they induced SRC-1 recruitment to ERbeta with much higher efficiency than in the case of ERalpha. The differential coactivator recruitment capacities of the ER agonists and their receptor subtype coactivator recruitment specificity may be linked to the molecular structure of the agonists with respect to their interactions with a specific histidine residue located at the back of the ligand-binding pocket. Altogether, these quantitative in vitro studies of ER interactions reveal the complex energetic and stoichiometric consequences of changes in the chemical structures of these proteins and their ligands.
Collapse
Affiliation(s)
- Emmanuel Margeat
- Centre de Biochimie Structurale, INSERM U554, CNRS UMR5048, 29, rue de Navacelles, 34090, Cedex, Montpellier, France
| | | | | | | | | | | |
Collapse
|
39
|
Abstract
The coexistence of ERalpha and ERbeta suggests that active receptor complexes are present as homo- or heterodimers. In addition each of three forms of active receptors may trigger different cellular responses. A real-time biosensor based on surface plasmon resonance was used as instrument to determine binding kinetics of homo- and heterodimerization of estrogen receptor alpha and beta. Partially purified full-length estrogen receptor alpha was expressed intracellularly as a C-terminal fusion to a hexa-histidine tag using the baculovirus-expression system. Purified estrogen receptor alpha and beta without tags were used as partners in the dimerization process. An association rate constant of 3.6 x 10(3) to 1.5 x 10(4)M(-1)s(-1) for the homodimer formation of ERalpha and 5.7 x 10(3) to 1.5 x 10(4)M(-1)s(-1) for the heterodimer formation was found assuming a pseudo first-order reaction kinetic. The equilibrium dissociation constant for homodimerization of ERalpha was 2.2 x 10(-8) to 5.4 x 10(-8) and 1.8 x 10(-8) to 2.6 x 10(-8)M for the heterodimer formation. The homo- and heterodimer formation was characterized by a slow association kinetics and kinetic rate constants were within the same range.
Collapse
Affiliation(s)
- Elisabeth Jisa
- Institute of Applied Microbiology, University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | | |
Collapse
|
40
|
Mueller SO. Overview of in vitro tools to assess the estrogenic and antiestrogenic activity of phytoestrogens. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 777:155-65. [PMID: 12270209 DOI: 10.1016/s1570-0232(02)00282-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
There is an intense discussion in the scientific and even more so in the public community as well as regulatory agencies about the potential benefits or detrimental effects of plant-derived compounds that may affect the endocrine system, especially estrogen signaling pathways. These so-called phytoestrogens are found in the normal western diet and predominantly in an eastern or soy-based diet and the potency of the isolated compounds to interact with the known receptors for estrogen varies tremendously. The estrogen receptors, ER alpha and ER beta, mediate the effects of endogenous estrogens, i.e. regulation of reproductive function, tissue development, cell proliferation and differentiation. In this review, in vitro test systems available to date for the screening of estrogenic and antiestrogenic activity including mechanism-based assays are described. The potency of phytoestrogens determined using these in vitro assays are compared with the potency of endogenous estrogens and results obtained in vitro are compared with effects in vivo. Finally, the impact of in vitro assays to determine estrogenicity on human hazard assessment is discussed as well as other non ER-mediated mechanisms that may contribute to potential beneficial or adverse effects of phytoestrogens in man.
Collapse
Affiliation(s)
- Stefan O Mueller
- Merck KGaA, Molecular Toxicology, Frankfurter Strasse 250, 64293, Darmstadt, Germany.
| |
Collapse
|
41
|
Vogel SK, Schulz A, Rippe K. Binding affinity of Escherichia coli RNA polymerase*sigma54 holoenzyme for the glnAp2, nifH and nifL promoters. Nucleic Acids Res 2002; 30:4094-101. [PMID: 12235394 PMCID: PMC137104 DOI: 10.1093/nar/gkf519] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Escherichia coli RNA polymerase associated with the sigma54 factor (RNAP*sigma54) is a holoenzyme form that transcribes a special class of promoters not recognized by the standard RNA polymerase*sigma70 com plex. Promoters for RNAP*sigma54 vary in their overall 'strength' and show differences in their response to the presence of DNA curvature between enhancer and promoter. In order to examine whether these effects are related to the promoter affinity, we have determined the equilibrium dissociation constant K(d) for the binding of RNAP*sigma54 to the three promoters glnAp2, nifH and nifL. Binding studies were conducted by monitoring the changes in fluorescence anisotropy upon titrating RNAP*sigma54 to carboxyrhodamine-labeled DNA duplexes. For the glnAp2 and nifH promoters similar values of K(d) = 0.94 +/- 0.55 nM and K(d) = 0.85 +/- 0.30 nM were determined at physiological ionic strength, while the nifL promoter displayed a significantly weaker affinity with K(d) = 8.5 +/- 1.9 nM. The logarithmic dependence of K(d) on the ionic strength I was -Deltalog(K(d))/Deltalog(I) = 6.1 +/- 0.5 for the glnAp2, 5.2 +/- 1.2 for the nifH and 2.1 +/- 0.1 for the nifL promoter. This suggests that the polymerase can form fewer ion pairs with the nifL promoter, which would account for its weaker binding affinity.
Collapse
Affiliation(s)
- Sabine K Vogel
- Deutsches Krebsforschungszentrum, Biophysik der Makromoleküle (H0500), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
| | | | | |
Collapse
|
42
|
Suárez T, Biswas SB, Biswas EE. Biochemical defects in retina-specific human ATP binding cassette transporter nucleotide binding domain 1 mutants associated with macular degeneration. J Biol Chem 2002; 277:21759-67. [PMID: 11919200 DOI: 10.1074/jbc.m202053200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The retina-specific human ABC transporter (ABCR) functions in the retinal transport system and has been implicated in several inherited visual diseases, including Stargardt disease, fundus flavimaculatus, cone-rod dystrophy, and age-related macular degeneration. We have previously described a general ribonucleotidase activity of the first nucleotide binding domain (NBD1) of human ABCR (Biswas, E. E. (2001) Biochemistry 40, 8181-8187). In this communication, we present a quantitative study analyzing the effects of certain disease-associated mutations, Gly-863 --> Ala, Pro-940 --> Arg, and Arg-943 --> Gln on the nucleotide binding, and general ribonucleotidase activities of this domain. NBD1 proteins, harboring these mutations, were created through in vitro site-specific mutagenesis and expressed in Escherichia coli. Results of the enzyme-kinetic studies indicated that these mutations altered the ATPase and CTPase activities of NBD1. The G863A and P940R mutations were found to have significant attenuation of the rates of nucleotide hydrolysis and binding affinities. On the other hand, the R943Q mutation had small, but detectable reduction in its nucleotidase activity and nucleotide binding affinity. We have measured the nucleotide binding affinities of NBD1 protein and its mutants quantitatively by fluorescence anisotropy changes during protein binding to ethenoadenosine ATP (epsilonATP), a fluorescent ATP analogue. We have correlated the dissociation constant (K(D)) and the rates of nucleotide hydrolysis (V(max)) of NBD1 and its mutants with the available genetic data for these mutations.
Collapse
Affiliation(s)
- Tatiana Suárez
- Department of Laboratory Sciences, Program in Biotechnology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | | | | |
Collapse
|
43
|
Baud S, Margeat E, Lumbroso S, Paris F, Sultan C, Royer C, Poujol N. Equilibrium binding assays reveal the elevated stoichiometry and salt dependence of the interaction between full-length human sex-determining region on the Y chromosome (SRY) and DNA. J Biol Chem 2002; 277:18404-10. [PMID: 11877434 DOI: 10.1074/jbc.m112366200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In an effort to better define the molecular mechanism of the functional specificity of human sex-determining region on the Y chromosome (SRY), we have carried out equilibrium binding assays to study the interaction of the full-length bacterial-expressed protein with a DNA response element derived from the CD3epsilon gene enhancer. These assays are based on the observation of the fluorescence anisotropy of a fluorescein moiety covalently bound to the target oligonucleotide. The low anisotropy value due to the fast tumbling of the free oligonucleotide in solution increases substantially upon binding the protein to the labeled target DNA. Our results indicate that the full-length human wild-type SRY (SRY(WT)) forms a complex of high stoichiometry with its target DNA. Moreover, we have demonstrated a strong salt dependence of both the affinity and specificity of the interaction. We have also addressed the DNA bending properties of full-length human SRY(WT) in solution by fluorescence resonance energy transfer and revealed that maximal bending is achieved with a protein to DNA ratio significantly higher than the classical 1:1. Oligomerization thus appears, at least in vitro, to be tightly coupled to SRY-DNA interactions. Alteration of protein-protein interactions observed for the mutant protein SRY(Y129N), identified in a patient presenting with 46,XY sex reversal, suggests that oligomerization may play an important role in vivo as well.
Collapse
Affiliation(s)
- Stephanie Baud
- Centre de Biochimie Structurale, UMR INSERM 554, CNRS 5048, Université Montpellier I, 29 rue de Navacelles, 34090 Montpellier, France
| | | | | | | | | | | | | |
Collapse
|
44
|
Yi P, Driscoll MD, Huang J, Bhagat S, Hilf R, Bambara RA, Muyan M. The effects of estrogen-responsive element- and ligand-induced structural changes on the recruitment of cofactors and transcriptional responses by ER alpha and ER beta. Mol Endocrinol 2002; 16:674-93. [PMID: 11923465 DOI: 10.1210/mend.16.4.0810] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Estrogen signaling is mediated by ER alpha and -beta. ERs are converted from an inactive form to a transcriptionally active state through conformational changes induced by ligand and estrogen-responsive element (ERE) sequences. We show here that ER alpha and ER beta bind to an ERE independently from ER ligands. We found that although the binding affinity of ER beta for an ERE is 2-fold lower than that of ER alpha, both ERs use the same nucleotides for DNA contacts. We show that both EREs and ligands are independent modulators of ER conformation. Specifically, the ERE primarily determines the receptor-DNA affinity, whereas the structure of the ER ligand dictates the affinity of ER for particular cofactors. We found that the ligand-dependent cofactor transcriptional intermediary factor-2, through a distinct surface, also interacts with ER alpha preferentially and independently of ligand. The extent of interaction, however, is dependent upon the ER-ERE affinity. In transfected cells, ER alpha is more transcriptionally active than ER beta. The ERE sequence, however, determines the potency of gene induction when either ER subtype binds to an agonist. Antagonists prevent ERs from inducing transcription independently from ERE sequences. Thus, ERE- and ligand-induced structural changes are independent determinants for the recruitment of cofactors and transcriptional responses. The ability of ER alpha to differentially recruit a cofactor could contribute to ER subtype-specific gene responses.
Collapse
Affiliation(s)
- Ping Yi
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Shchelkunova TA, Rubtsov PM, Levina IS, Kamerntsky AV, Smirnov AN. Pregna-D'-pentarane structure influences progesterone receptor affinity for DNA. Steroids 2002; 67:323-32. [PMID: 11958787 DOI: 10.1016/s0039-128x(01)00188-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electrophoretic mobility shift assay was used to determine whether pregna-D'-pentaranes allow progesterone receptor (PR) from rat uterine cytosol to bind hormone response element (HRE)-containing oligonucleotide duplexes and to measure the affinity of this interaction. The formation of DNA-protein complexes in low salt medium was progesterone-related ligand-, temperature-, and PR-dependent, and specific for HRE. The highest affinity of PR to DNA (equilibrium K(a) = 0.420 +/- 0.185 nM(-1)) was found in the presence of the partial agonist/antagonist RU486, while the lowest affinity (K(a) = 0.074 +/- 0.013 nM(-1)) was demonstrated with the full agonist 6alpha-methyl-16alpha,17alpha-cyclohexanoprogesterone. With the exception of the strong full agonist R5020, there was a tendency toward correlation between the induced lower affinity of PR for DNA in the context of tyrosine aminotransferase HRE and the full agonistic activity of tested compounds.
Collapse
Affiliation(s)
- T A Shchelkunova
- Lab. of Endocrinology, School of Biology, Moscow Lomonosov State University, Lenin Hills 1/12, 119899 Moscow, Russia
| | | | | | | | | |
Collapse
|
46
|
Jones G, Wozniak M, Chu Y, Dhar S, Jones D. Juvenile hormone III-dependent conformational changes of the nuclear receptor ultraspiracle. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2001; 32:33-49. [PMID: 11719067 DOI: 10.1016/s0965-1748(01)00077-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The identification of potential endogenous or synthetic ligands for orphan receptors in the steroid receptor superfamily is important both for discerning endogenous regulatory pathways and for designing receptor inhibitors. The insect nuclear receptor Ultraspiracle (USP), an ortholog of vertebrate RXR, has long been treated as an orphan receptor. We have tested here the fit of terpenoid ligands to the JH III-binding site of monomeric and homo-oligomeric USP from Drosophila melanogaster (dUSP). dUSP specifically bound juvenile hormone III (JH III), but not control farnesol or JH III acid, and also specifically changed in conformation upon binding of JH III in a fluorescence binding assay. Juvenile hormone III binding caused intramolecular changes in receptor conformation, and stabilized the receptor's dimeric/oligomeric quaternary structure. In both a radiometric competition assay and the fluorescence binding assay the synthetic JH III agonist methoprene specifically competed with JH III for binding to dUSP, the first demonstration of specific binding of a biologically active JH III analog to an insect nuclear receptor. The recombinant dUSP bound with specificity to a DR12 hormone response element in a gel shift assay. The same DR12 element conferred enhanced transcriptional responsiveness of a transfected juvenile hormone esterase core promoter to treatment of transfected cells with JH III, but not to treatment with retinoic acid or T3. The activity of JH III or JH III-like structures, but not structures without JH III biological activity, to bind specifically to dUSP and activate its conformational change, provide evidence of a terpenoid endogenous ligand for Ultraspiracle, and offer the prospect that synthetic, terpenoid structures may be discovered that can agonize or antagonize USP function in vivo.
Collapse
Affiliation(s)
- G Jones
- School of Biological Sciences, University of Kentucky, Lexington, KY 40506, USA
| | | | | | | | | |
Collapse
|
47
|
Tyulmenkov VV, Klinge CM. A mathematical approach to predict the affinity of estrogen receptors alpha and beta binding to DNA. Mol Cell Endocrinol 2001; 182:109-19. [PMID: 11500244 DOI: 10.1016/s0303-7207(01)00508-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Estrogen receptors alpha and beta (ERalpha and ERbeta) bind to specific DNA sequences, estrogen response elements (EREs), usually located in the promoters of estrogen-regulated genes. The consensus ERE contains two inverted repeats of the 5'-AGGTCA-3' half-site (1/2 ERE) separated by three base pairs (bp). Many estrogen-responsive gene promoters contain one or more direct repeats (DR) of 1/2 ERE. Here, we examined the affinity of ERalpha and ERbeta binding and estradiol (E(2))-induced transactivation from select EREs and DRs. The affinity of ERalpha and ERbeta binding to imperfect EREs in vitro can be predicted from equations using the number of 1/2 EREs and the number of (AT)-(GC) bp substitutions within the 15-bp candidate ERE sequence as independent variables. Transactivation by ERalpha and ERbeta correlates with the affinity of ER-ERE binding with the exception of ERalpha from two low-affinity EREs. The equations developed here can be used to screen the promoters of estrogen-responsive genes for candidate ERE sequences.
Collapse
Affiliation(s)
- V V Tyulmenkov
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | | |
Collapse
|
48
|
Abstract
The estrogen receptor (ER) is a ligand-activated enhancer protein that is a member of the steroid/nuclear receptor superfamily. Two genes encode mammalian ER: ERalpha and ERbeta. ER binds to specific DNA sequences called estrogen response elements (EREs) with high affinity and transactivates gene expression in response to estradiol (E(2)). The purpose of this review is to summarize how natural and synthetic variations in the ERE sequence impact the affinity of ER-ERE binding and E(2)-induced transcriptional activity. Surprisingly, although the consensus ERE sequence was delineated in 1989, there are only seven natural EREs for which both ERalpha binding affinity and transcriptional activation have been examined. Even less information is available regarding how variations in ERE sequence impact ERbeta binding and transcriptional activity. Review of data from our own laboratory and those in the literature indicate that ERalpha binding affinity does not relate linearly with E(2)-induced transcriptional activation. We suggest that the reasons for this discord include cellular amounts of coactivators and adaptor proteins that play roles both in ER binding and transcriptional activation; phosphorylation of ER and other proteins involved in transcriptional activation; and sequence-specific and protein-induced alterations in chromatin architecture.
Collapse
Affiliation(s)
- C M Klinge
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
| |
Collapse
|
49
|
Worthington MT, Pelo J, Luo RQ. Cloning of random oligonucleotides to create single-insert plasmid libraries. Anal Biochem 2001; 294:169-75. [PMID: 11444813 DOI: 10.1006/abio.2001.5162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Random double-stranded oligonucleotides are useful reagents to identify the optimal binding sites for DNA-binding proteins, such as transcriptional activators. Some applications require ligation of random oligonucleotides to form plasmid-based libraries such as the yeast one-hybrid system, where the activation of a cloned DNA sequence from a library of random DNA-binding sequences activates a reporter gene. Current theories do not account for the low efficiencies of oligonucleotide-based plasmid library construction methods. We developed a technique to clone single oligonucleotides into plasmid vectors with high efficiency that predictably results in only one oligonucleotide insert per colony and used this method to clone a yeast one-hybrid library. This method, either as presented or with modifications, should be suitable for any situation where high-efficiency cloning of single oligonucleotide inserts is desired.
Collapse
Affiliation(s)
- M T Worthington
- The Digestive Health Research Center, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908, USA.
| | | | | |
Collapse
|
50
|
Szatkowski Ozers M, Hill JJ, Ervin K, Royer CA, Gorski J. The dissociation rate of estrogen receptor alpha from the consensus estrogen response element. Mol Cell Endocrinol 2001; 175:101-9. [PMID: 11325520 DOI: 10.1016/s0303-7207(01)00395-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The rate of dissociation of recombinant, purified human estrogen receptor alpha (ERalpha) from a fluorescein-labeled DNA containing the consensus vitellogenin ERE sequence (F-vitERE) was determined in real time using fluorescence anisotropy. The complex of estradiol-occupied ERalpha with F-vitERE had an apparent dissociation rate of 1.48+/-0.06x10(-2) s(-1) and a half-life of 46.6 s at room temperature. The dissociation rate was characterized by a single exponential decay, suggesting that ER dissociates from the DNA as a preformed dimer, rather than as two individual monomers. The association rate of estradiol-occupied ERalpha for the F-vitERE was calculated as 7x10(6) M(-1) s(-1) based on the dissociation rate measured and previous determinations of the equilibrium dissociation constant (Kd) in similar assay conditions (Ozers et al., 1997). In buffer containing various concentrations of salt, the rate of dissociation of estradiol-occupied ERalpha from F-vitERE was accelerated by increasing salt concentrations. Compared to estradiol-occupied ERalpha, the rate of dissociation of unoccupied ERalpha from the F-vitERE was very similar, indicating that estradiol occupancy does not affect the dissociation rate of ERalpha from the ERE.
Collapse
Affiliation(s)
- M Szatkowski Ozers
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | | | | | | | | |
Collapse
|