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1

Modeling of Coupled Degradation, Sorption, and Transport of 17beta-Estradiol in Undisturbed Soil  

Technology Transfer Automated Retrieval System (TEKTRAN)

The presence of 17 beta-estradiol in the environment, even at part-per trillion concentrations, may raise significant concern regarding the health of aquatic organisms. Once 17 beta-estradiol is released into the environment from human and animal sources, its fate and transport is controlled by fact...

2

The APOE4 genotype alters the response of microglia and macrophages to 17beta-estradiol.  

PubMed

The apolipoprotein E4 (APOE4) gene is a well-known risk factor for Alzheimer's disease (AD) and other neurological disorders. Post-menopausal women with AD who express at least one APOE4 gene have more severe neuropathology and worsened cognitive scores than their non-expressing counterparts. Since 17beta-estradiol down-regulates inflammation as part of its neuroprotective role, we examined the effect of 17beta-estradiol on the response of microglia to immune activation as a function of APOE genotype. Our data show that the anti-inflammatory activity of 17beta-estradiol is significantly reduced in APOE4 targeted replacement mice compared to APOE3 mice. A significant interaction between APOE genotype and the response to 17beta-estradiol was observed for NO and cytokine production by immune activated microglia. The genotype specific effect was not restricted to brain macrophages since peritoneal macrophages from APOE4 ovariectomized mice also demonstrated a significant difference in 17beta-estradiol responsiveness. ERbeta protein levels in APOE4 microglia were higher than APOE3 microglia, suggesting a difference in post-translational protein regulation in the presence of the APOE4 gene. Overall, our data indicate that the APOE genotype may be a critical component in assessing the effectiveness of 17beta-estradiol's action and may impact the neuroprotective role of 17beta-estradiol and of hormone replacement therapy on brain function when the APOE4 gene is expressed. PMID:17553597

Brown, Candice M; Choi, Emily; Xu, Qing; Vitek, Michael P; Colton, Carol A

2008-12-01

3

Influence of 17-beta-estradiol on cerebrovascular impedance during menstrual cycle in women.  

PubMed

Numerous experimental studies showed that estrogen alters diameters of cerebral arteries by modifying production of vasoactive substances. In this study, we address a question whether increased concentration of 17-beta-estradiol (E2) during a typical menstrual cycle of young, healthy women influences cerebrovascular impedance, as measured with Doppler pulsatility index (PI) in the common (CCA), internal (ICA), and external (ECA) carotid arteries using duplex Doppler sonography. PI was determined and correlated with plasma E2 concentration in 14 women (ages 23-25) throughout their menstrual cycle. The concentration of E2 increased in the follicular phase of the cycle and reached a peak of 140-300 pg/ml on days 13 and 14, whereas concentration of progesterone remained low (<1 ng/ml). Along with an increase in E2 concentration, the ICA PI decreased from its initial level on average by 11% on day 13 and by 7% on day 14 (r=-0.41, P<0.05). In contrast, the value of the ECA PI showed an increasing trend during the peak of E2 concentration. There were no significant changes in the CCA PI as well as in the systolic blood pressure, heart rate, hematocrit, and hemoglobin concentration during the menstrual cycle. Cerebral vascular impedance in young women is modulated by concentration of E2 throughout the menstrual cycle. The decrease in the ICA PI during the late follicular phase seems to be attributed to a decrease in cerebrovascular resistance. PMID:15178215

Krejza, Jaroslaw; Mariak, Zenon; Nowacka, Agnieszka; Melhem, Elias R; Babikian, Viken L

2004-06-15

4

Optimization of rate-controlled 17beta-estradiol nanoparticles for cerebral ischemia therapy.  

PubMed

The objective of this study was to prepare and evaluate rate-controlled 17beta-estradiol nanoparticles (E2-NPs), and then optimize them by central composite design (CCD) using a response surface methodology (RSM). The E2-NPs were designed for cerebral ischemia therapy and prepared by oil-in-water (o/w) emulsion by mixing E2 and phosphatidylcholine, cross-linking of the bovine serum albumin (BSA) wall material with glutaraldehyde, and subsequently creating a biodegradable coating shell with L-arginine. In two-factor, five-level CCD, the independent variables were the pH value of the aqueous phase (X1) and the amount of glutaraldehyde (X2). The optimal formulation of the E2-NPs was developed from the response equations of each fitted model. The optimal E2-NPs particle size was 92.4 +/- 1.4 nm, and its cumulative release in 4.0 h (therapeutic window for stroke) was 71.17 +/- 0.24%, with a zero-order release model of 24 h. The preparation and testing of the optimal formulation showed a good correlation between the predicted and observed values. In addition, a brain microdialysis study demonstrated that the E2-NPs had the ability to penetrate the blood-brain barrier and clearly increase and maintain the drug concentration in the brain over 12 h. Furthermore, the E2-NPs reduced brain infarct size in rats with middle cerebral artery occlusion (MCAO)-induced stroke. These results suggest that rate-controlled E2-NPs increase the efficacy of E2 for ischemic stroke therapy. PMID:24015502

Chang, Li-Ching; Cheng, Chun-Jen; Tsai, Tung-Hu; Liu, Ching-Wen; Tsai, Tong-Rong

2013-10-01

5

17beta-estradiol prevents blood-brain barrier disruption induced by VEGF.  

PubMed

We performed this study to determine how pretreatment of the ovariectomized rats with 17beta-estradiol could affect blood-brain barrier disruption caused by the vascular endothelial growth factor (VEGF), an important mediator of vascular permeability. Ovariectomized female rats aged twelve to fourteen weeks were used in the study. A 500 micro g 17beta-estradiol 21-day release pellet was implanted in the 17beta-estradiol group, and a vehicle pellet was implanted in the control group 21 days before the experiments. We performed three craniotomies under isoflurane anesthesia to expose cerebral cortices. Normal saline, 10 (- 10)M and 10 (- 9)M VEGF patches were applied on each hole for 30 min. The transfer coefficient (Ki) of (14)C-alpha-amino isobutyric acid and volume of (3)H-dextran (70,000 dalton) distribution were determined to measure the degree of BBB disruption. Ki was increased by 108 % and 138 % with 10 (- 10)M and 10 (- 9)M VEGF respectively after VEGF application in the control group (p < 0.01). However, there was no significant increase in the Ki with the VEGF application in the 17beta-estradiol group, and their values were significantly lower than the corresponding data of the control group (10 (- 10)M: - 55 %, 10 (- 9)M: - 52 %, p <0.05). The volume of dextran distribution in the control group increased by 47 % with VEGF 10 (- 9)M (p < 0.05), whereas there was no significant change in the volume of dextran distribution with VEGF application in the 17beta-estradiol group and the volume was lower than the corresponding volume of the vehicle-treated control group (10 (- 10)M: - 34 %, 10 (- 9)M: -32 %, p < 0.05). In conclusion, our study demonstrated that chronic 17beta-estradiol treatment prevented BBB disruption induced by the VEGF in the ovariectomized rats. PMID:15156404

Chi, O Z; Barsoum, S; Wen, Y; Liu, X; Weiss, H R

2004-05-01

6

Persistence and Fate of 17beta-estradiol and testosterone in agricultural soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Steroidal hormones are constantly released into the environment by man-made and natural sources. The goal of this study was to examine the persistence and fate of 17beta-estradiol and testosterone, the two primary natural hormones. Incubation experiments were conducted under aerobic and anaerobic co...

7

Distribution of estrogens, 17beta-estradiol and estrone, in Canadian municipal wastewater treatment plants.  

PubMed

The distribution of female hormones, 17beta-estradiol and estrone, was determined in effluents of 18 selected municipal treatment plants across Canada. Replicate 24-h composite samples were collected from the influent and final effluent of each treatment plant, and the removal efficiency compared to the operational characteristics of the plants. In conventional activated sludge and lagoon treatment systems, the mean concentrations of 17beta-estradiol and estrone in influent were 15.6 ng/l (range 2.4-26 ng/l) and 49 ng/l (19-78 ng/l). In final effluents, the mean concentrations of both 17beta-estradiol and estrone were reduced to 1.8 ng/l (0.2-14.7 ng/l) and 17 ng/l (1-96 ng/l), respectively. 17beta-estradiol was removed effectively, >75% and as high as 98%, in most of the conventional mechanical treatment systems with secondary treatment. The removal of estrone was much more complex with removal varying from 98% to situations where the concentrations in the effluent were elevated above that detected in the influent. The estrogenicity, measured using a transfected estrogen receptor in yeast (YES) assay, was also variable, ranging from high removal to elevations of estrogenicity in final effluent. Although the apparent removals were not statistically correlated with either hydraulic (HRT) or solid (SRT) retention times, plants or lagoons with high SRT were very effective at reducing the levels of hormones. Well-operated plants that achieved nitrification also tended to have higher removal of hormones than those that did not nitrify. Laboratory aerobic reactor experiments confirmed the rapid removal of 17beta-estradiol, estrone, and estrogenicity when exposed to sewage slurries. PMID:15589256

Servos, M R; Bennie, D T; Burnison, B K; Jurkovic, A; McInnis, R; Neheli, T; Schnell, A; Seto, P; Smyth, S A; Ternes, T A

2005-01-01

8

Regioselective 2-hydroxylation of 17{beta}-estradiol by rat cytochrome P4501B1  

SciTech Connect

Previous work demonstrated that human cytochrome P4501B1 (CYP1B1) forms predominantly 4-hydroxyestradiol (4-OHE2), a metabolite which is carcinogenic in animal models. Here, we present results from kinetic studies characterizing the formation of 4-OHE2 and 2-hydroxyestradiol (2-OHE2) by rat CYP1B1 using 17{beta}-estradiol (E2) as a substrate. K {sub m} and K {sub cat} values were estimated using the Michaelis-Menten equation. For rat CYP1B1, the apparent K {sub m} values for the formation of 4-OHE2 and 2-OHE2 were 0.61 {+-} 0.23 and 1.84 {+-} 0.73 {mu}M; the turnover numbers (K {sub cat}) were 0.23 {+-} 0.02 and 0.46 {+-} 0.05 pmol/min/pmol P450; and the catalytic efficiencies (K {sub cat}/K {sub m}) were 0.37 and 0.25, respectively. For human CYP1B1, the apparent K {sub m} values for the formation of 4-OHE2 and 2-OHE2 were 1.22 {+-} 0.25 and 1.10 {+-} 0.26; the turnover numbers were 1.23 {+-} 0.06 and 0.33 {+-} 0.02; and the catalytic efficiencies were 1.0 and 0.30, respectively. The turnover number ratio of 4- to 2-hydroxylation was 3.7 for human CYP1B1 and 0.5 for rat CYP1B1. These results indicate that, although rat CYP1B1 is a low K {sub m} E2 hydroxylase, its product ratio, unlike the human enzyme, favors 2-hydroxylation. The K {sub i} values of the inhibitor 2,4,3',5'-tetramethoxystilbene (TMS) for E2 4- and 2-hydroxylation by rat CYP1B1 were 0.69 and 0.78 {mu}M, respectively. The K {sub i} values of 7,8-benzoflavone ({alpha}-NF) for E2 4- and 2-hydroxylation by rat CYP1B1 were 0.01 and 0.02 {mu}M, respectively. The knowledge gained from this study will support the rational design of CYP1B1 inhibitors and clarify results of CYP1B1 related carcinogenesis studies performed in rats.

Rahman, Mostafizur [W. Harry Feinstone Center for Genomic Research, University of Memphis, Memphis, TN 38152 (United States); Department of Chemistry, University of Memphis, Memphis, TN 38152 (United States); Hayes Sutter, Carrie [W. Harry Feinstone Center for Genomic Research, University of Memphis, Memphis, TN 38152 (United States); Emmert, Gary L. [Department of Chemistry, University of Memphis, Memphis, TN 38152 (United States); Sutter, Thomas R. [W. Harry Feinstone Center for Genomic Research, University of Memphis, Memphis, TN 38152 (United States) and Department of Chemistry, University of Memphis, Memphis, TN 38152 (United States)]. E-mail: tsutter@memphis.edu

2006-11-01

9

Estrogen receptor alpha signaling in inflammatory leukocytes is dispensable for 17beta-estradiol-mediated inhibition of experimental autoimmune encephalomyelitis.  

PubMed

Estrogen treatment has been shown to exert a protective effect on experimental autoimmune encephalomyelitis (EAE), and is under clinical trial for multiple sclerosis. Although it is commonly assumed that estrogens exert their effect by modulating immune functions, we show in this study that 17beta-estradiol (E2) treatment can inhibit mouse EAE without affecting autoantigen-specific T cell responsiveness and type 1 cytokine production. Using mutant mice in which estrogen receptor alpha (ERalpha) has been unambiguously inactivated, we found that ERalpha was responsible for the E2-mediated inhibition of EAE. We next generated irradiation bone marrow chimeras in which ERalpha expression was selectively impaired in inflammatory T lymphocytes or was limited to the radiosensitive hemopoietic compartment. Our data show that the protective effect of E2 on clinical EAE and CNS inflammation was not dependent on ERalpha signaling in inflammatory T cells. Likewise, EAE development was not prevented by E2 treatment in chimeric mice that selectively expressed ERalpha in the systemic immune compartment. In conclusion, our data demonstrate that the beneficial effect of E2 on this autoimmune disease does not involve ERalpha signaling in blood-derived inflammatory cells, and indicate that ERalpha expressed in other tissues, such as CNS-resident microglia or endothelial cells, mediates this effect. PMID:15294957

Garidou, Lucile; Laffont, Sophie; Douin-Echinard, Victorine; Coureau, Christiane; Krust, Andrée; Chambon, Pierre; Guéry, Jean-Charles

2004-08-15

10

Regucalcin is expressed in rat mammary gland and prostate and down-regulated by 17beta-estradiol.  

PubMed

Regucalcin is involved in maintenance of calcium homeostasis due to the activation of Ca2+ pumping enzymes in the plasma membrane. It has a suppressive effect in cell proliferation, DNA and RNA synthesis, and may be associated with the abnormal cell division on tumor tissues. On the other hand both estrogens and Ca2+ are implicated in breast and prostate cancer but there are no studies focused on the expression of regucalcin in rat mammary gland or prostate. Furthermore, it is known that the expression of regucalcin in rat liver and kidney is regulated by 17beta-estradiol (E2). The aim of this study is to analyze if regucalcin is expressed in rat mammary gland and prostate and if it is regulated by E2 in these tissues. We demonstrated for the first time that regucalcin mRNA and protein are present in rat mammary gland and prostate by in situ hybridization and immunohistochemistry, respectively. Furthermore, we show by Real-time PCR that E2 down-regulates regucalcin expression in rat mammary gland and prostate. PMID:18157649

Maia, Claudio J B; Santos, Cecilia R; Schmitt, Fernando; Socorro, Sílvia

2008-04-01

11

Stimulation of growth and changes in the hepatic transcriptome by 17beta-estradiol in the yellow perch (Perca flavescens).  

PubMed

The effects of dietary 17beta-estradiol (E(2)) on growth and liver transcriptomics were investigated in the yellow perch (Perca flavescens). After a 3-mo treatment, E(2) significantly stimulated an increase in length and weight of juvenile male and female perch relative to control animals. The increase was significantly greater in females compared with males. Separate, unnormalized cDNA libraries were constructed from equal quantities of RNA from 6 male and 6 female livers of E(2)-treated and control perch, and 3,546 and 3,719 expressed sequence tags (ESTs) were obtained, respectively. To characterize E(2)-regulated transcripts, EST frequencies between libraries were calculated within contiguous sequences that were assembled from the combined ESTs of both libraries. Frequencies were also determined in EST transcript groupings produced by aligning all of the ESTs from both libraries at the nucleotide level. From these analyses, there were 28 annotated transcripts that were regulated by 75% between libraries and for which there were at least 5 ESTs of the same transcript between libraries. Regulation of a subset (14) of these transcripts was confirmed by quantitative reverse transcription-polymerase chain reaction (QPCR). Transcripts that were upregulated by E(2) included reproduction-related proteins, binding proteins, and proteases and protease inhibitors. While not part of the transcript frequency analysis, QPCR showed significant upregulation of estrogen receptor esr1 and of insulin-like growth factor I (IGF-I) in E(2) livers. E(2)-downregulated transcripts represented a variety of functional categories including components of the respiratory chain, lipid transport and metabolism, glycolysis, amino acid and nitrogen metabolism, binding proteins, a hydrolytic enzyme, and a transcriptional regulator. In perch it appears that exogenous estrogen drastically shifts liver metabolism toward the production of lipoproteins and carbohydrate binding proteins, and that the growth-promoting action may involve an increase in hepatic IGF-I production. PMID:19549814

Goetz, Frederick W; Rise, Matthew L; Rise, Marlies; Goetz, Giles W; Binkowski, Frederick; Shepherd, Brian S

2009-08-01

12

Differential effects of 17beta-estradiol and testosterone on the contractile responses of porcine coronary arteries.  

PubMed

1. We investigated the effects of short-term exposure to physiological levels of 17beta-estradiol and testosterone on vasocontractile responses in porcine coronary artery rings. 2. Concentration-response curves to endothelin-1, 5-hydroxytryptamine, the thromboxane analogue U46619 and KCl were constructed in endothelium-intact and endothelium-disrupted artery rings. 3. Thirty minutes exposure to 17beta-estradiol (1 and 30 nM) significantly attenuated vasoconstriction to endothelin-1, 5-hydroxytryptamine and U46619. Conversely, the same concentrations of testosterone significantly potentiated responses elicited by these contractile agents. These inhibitory effects of 17beta-estradiol and enhancing actions of testosterone on contractions were endothelium-independent. KCl-mediated contractions were unaffected by the presence of either sex hormones. 4. The oestrogen receptor antagonists, tamoxifen (10 microM) and ICI 182,780 (10 microM), were unable to reverse the inhibitory influence 1 nM 17beta-estradiol had on the agonist-mediated contractile responses. Similarly, the androgen receptor antagonists, flutamide (10 microM) and cyproterone acetate (10 microM), failed to affect the potentiating activities of 1 nM testosterone. The alteration in vasoconstrictive responses observed following acute exposure to either 1 nM 17beta-estradiol and 1 nM testosterone were apparent even in the presence of the protein synthesis inhibitor cycloheximide (10 microM) and the transcription inhibitor actinomycin D (10 microM). 6. In conclusion, we report a unique type of sex hormone action on the coronary vasculature. These events occur at low nanomolar concentrations of 17beta-estradiol and testosterone, are insensitive to conventional sex hormone receptor antagonists, are not blocked by de novo protein synthesis inhibitors and have rapid time-courses that are uncharacteristic of classical genomic activities. PMID:10742284

Teoh, H; Quan, A; Leung, S W; Man, R Y

2000-04-01

13

17 beta-estradiol inhibition of Leydig cell regeneration in the ethane dimethylsulfonate-treated mature rat.  

PubMed

This study was designed to determine the effects of 17 beta-estradiol (E2) on Leydig cell development in the rat. Mature (60 to 65 days old) male rats received a single intraperitoneal injection of ethane dimethylsulfonate (EDS, 100 mg/kg body weight); untreated rats served as controls. In one series of experiments, groups of EDS-treated rats also received daily injections of either E2 (25 micrograms/100 g body weight), human chorionic gonadotropin (hCG, 20 IU/day), a combination of the two, or vehicle only (EDS controls). Animals were killed on days 2, 4, 10, 16, 24, 30, and 36 after EDS treatment. In another series of experiments, groups of EDS-treated rats received daily injections of hCG and E2 during days 0 through 5, 5 through 30, or 16 through 30 after EDS treatment, and were killed on day 30. In both series of experiments, the steroidogenic capacity and hCG binding capacity of the Leydig cells were examined in short-term in vitro incubations using collagenase-dispersed interstitial cells. Testes were also prepared and examined histologically by light and electron microscopy. E2 treatment of animals during the initial 5 days after EDS administration had no effect on the regeneration of interstitial cells and Leydig cells. Treatment with E2 during days 5 to 30 post-EDS blocked the regeneration of Leydig cells and thereby significantly reduced the increase in interstitial cell numbers. Finally, when E2 treatment was delayed until 16 days post-EDS, there was no significant reduction in the regeneration of interstitial or Leydig cells. These data suggest that an important developmental process that is necessary for Leydig cell regeneration occurs between days 5 and 16 post-EDS.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1662673

Abney, T O; Myers, R B

1991-01-01

14

17beta-estradiol stimulates ascorbic acid and LHRH release from the medial basal hypothalamus in adult male rats.  

PubMed

In the present investigation, 17beta-estradiol (E(2)) and tamoxifen, an antiestrogen, were evaluated for their effects on the release of ascorbic acid (AA) and luteinizing hormone-releasing hormone (LHRH). Medial basal hypothalami (MBH) from adult male rats were incubated with graded concentrations of E(2) (10 (-9) to 10(-6) M) or a combination of E(2) (10(-7) M) and tamoxifen (10(-7) and 10(-6) M ) in 0.5 ml of Krebs Ringer bicarbonate buffer for 1 hr. AA and LHRH in the incubation medium were measured by high-performance liquid chromatography and radioimmunoassay, respectively. E(2) significantly elevated both AA and LHRH release and the minimal effective dose was 10(-7) M. A combination of E(2) (10(-7) M) and tamoxifen (10(-6) M) totally blocked E(2)-induced AA and LHRH release. The stimulatory effect of E(2) was also suppressed in the presence of N(G)-monomethyl-L-arginine, a competitive inhibitor of nitric oxide synthase (NOS), illustrating that the release is mediated by nitric oxide (NO). To further characterize the role of NO, the tissues were incubated with E(2) or a combination of E(2) + (6 anilino-5, 8-quinolinedione) LY 83583 (10(-6) and 10(-5) M), an inhibitor of NOS. LY 83583 was effective in suppressing E(2)-induced AA and LHRH release, demonstrating that the effect was mediated by cyclic GMP. Incubation of the tissues with E(2) or a combination of E(2) + 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (O.D.Q.) (10(-5) and 10(-4) M), a specific inhibitor of soluble guanylyl cyclase failed to alter AA release but significantly suppressed LHRH release. The role of a prostaglandin synthesis blocker in E(2)-induced AA and LHRH release was tested by incubating the tissues with E(2) or a combination of E(2) + indomethacin (1.8 x 10 (-7) or 1.8 x 10(-6) M). Indomethacin produced a significant decrease in E(2)-induced AA and LHRH release, suggesting that the release process required prostaglandins as an intracellular mediator. In conclusion, E(2) stimulated both AA and LHRH release and the effect was mediated by NO and prostaglandins. PMID:15388888

Karanth, Sharada; Yu, Wen H; Mastronardi, Claudio M; McCann, Samuel M

2004-10-01

15

Dual derivatization-stir bar sorptive extraction--thermal desorption--gas chromatography-mass spectrometry for determination of 17beta-estradiol in water sample.  

PubMed

A novel method for the trace analysis of 17beta-estradiol (E2) in river water sample was developed, which involved stir bar sorptive extraction (SBSE) with in situ acylation (first derivatization) and thermal desorption (TD) with quartz wool assisted (QWA) in tube silylation (second derivatization), followed by gas chromatography-mass spectrometry (GC-MS), and is called the "dual derivatization method." The optimum conditions for SBSE with in situ acylation, such as the volume of acetic acid anhydride and the extraction time, were investigated. In addition, the optimum conditions for TD with QWA in tube silylation, such as the volume of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and the TD temperature and hold time, were investigated as well. The detection limit (S/N = 3) and the quantitation limit (S/N>10) of E2 in the river water sample were 0.5 and 2 pg ml(-1) (ppt), respectively, by the dual derivatization method. In addition, the detection limit was 0.1 pg ml(-1) by using dual derivatization method with multi-shot mode. The calibration curve for E2 was linear in the range of 0.002-10 ng ml(-1) with correlation coefficients >0.999. The average recoveries of E2 (n = 6) at the concentrations of 0.05 and 1.0 ng ml(-1) from the river water sample were 93.1 (RSD: 1.4%) and 98.4% (RSD: 0.8%), respectively, with correction using the added surrogate standard, 17beta-estradiol-(13)C(4). This simple, accurate, sensitive and selective analytical method may be applicable to the determination of trace amounts of E2 in water samples. PMID:16439260

Kawaguchi, Migaku; Ito, Rie; Sakui, Norihiro; Okanouchi, Noriya; Saito, Koichi; Nakazawa, Hiroyuki

2006-02-10

16

A HOXA10 Estrogen Response Element (ERE) is Differentially Regulated by 17 Beta-estradiol and Diethylstilbestrol (DES)  

Microsoft Academic Search

The molecular mechanisms by which estrogens regulate developmental gene expression are poorly understood. While 17 beta-estradiol is normally present at high concentrations in pregnancy, exposure to the estrogen diethylstilbestrol (DES) in utero induces developmental anomalies of the female reproductive tract. HOX gene expression is altered by DES, leading to abnormal Müllerian duct differentiation. The mechanism of ligand-specific regulation of HOX

G Eda Akbas; Joon Song; Hugh S Taylor

2004-01-01

17

The influence of body condition on 17-beta estradiol levels in relation to vitellogenesis in female Vipera aspis (Reptilia, Viperidae).  

PubMed

Seventy-six wild Vipera aspis females were caught over 3 years and placed in outdoor enclosures; 39 reproduced and 37 did not. Almost all the reproductive females had a body condition index (BCI) greater than 0.70 when vitellogenesis began. Monthly blood samples were taken by cardiac puncture. The main plasma parameters of vitellogenesis were measured by spectrophotometry: total plasma calcium, phosphorus, phospholipids, cholesterol, triglycerides, proteins, and albumin. Plasma 17-beta estradiol levels were determined by RIA. Vitellogenesis started soon after hibernation in reproductive females with very high 17-beta estradiol concentrations (average of 4.00 ng/ml) and there was a marked mobilization of maternal reserves (fat bodies, liver, and vertebral bone) associated with very high values of plasma calcium, phosphorus, phospholipids, cholesterol, triglycerides, and proteins. The kinetics of the main plasma components were described throughout the vitellogenesis period (from March to early June), when all plasma parameters differed markedly between reproductive and nonreproductive females. After ovulation, the differences between the two groups of females disappeared except in the case of albumin, which remained at a very low level in reproductive females for 6 months. All nonreproductive females had low 17-beta estradiol plasma levels during vitellogenesis (average of 0.08 ng/ml) and there was no suggestion of mobilization of maternal reserves. After vitellogenesis plasma concentrations of estradiol were low in reproductive (an average of 0.08 ng/ml) and in nonreproductive animals (0.06 ng/ml). Five nonreproductive females kept in the laboratory were estrogenized by 17-beta estradiol silastic implants. The 17-beta estradiol concentrations were close to those measured in reproductive females during vitellogenesis. Maternal reserves were mobilized, with almost all metabolic parameters exhibiting the vitellogenic pattern. When the silastic implants were removed, 17-beta estradiol concentrations dropped sharply to a basal level, but the other components were maintained near the vitellogenic values for several months. In contrast to previous studies on viviparous snakes, these results suggest that in V. aspis 17-beta estradiol levels are linked strictly to vitellogenesis. PMID:8194742

Bonnet, X; Naulleau, G; Mauget, R

1994-03-01

18

Fathead minnow vitellogenin: Complementary DNA sequence and messenger RNA and protein expression after 17{beta}-estradiol treatment  

SciTech Connect

Induction of vitellogenin (VTG) in oviparous animals has been proposed as a sensitive indicator of environmental contaminants that activate the estrogen receptor. In the present study, a sensitive ribonuclease protection assay (RPA) for VTG messenger RNA (mRNA) was developed for the fathead minnow (Pimephales promelas), a species proposed for routine endocrine-disrupting chemical (EDC) screening. The utility of this method was compared with an enzyme-linked immunosorbent assay (ELISA) specific for fathead minnow VTG protein. Assessment of the two methods included kinetic characterization of the plasma VTG protein and hepatic VTG mRNA levels in male fathead minnows following intraperitoneal injections of 17{beta}-estradiol (E2) at two dose levels (0.5, 5.0 mg/kg). Initial plasma E2 concentrations were elevated in a dose-dependent manner but returned to normal levels within 2 d. Lover VTG mRNA was detected within 4 h, reached a maximum around 48 h, and returned to normal levels in about 6 d. Plasma VTG protein was detectable within 16 h of treatment reached maximum levels at about 72 h. and remained near these maximum levels for at least 18 d. While the RPA was about 1,000 times more sensitive than the ELISA, the ELISA appears superior for routine screening tests. The ELISA method is relatively simple to perform and, because males lack a clearance mechanism for VTG, the protein remains at relatively high concentrations in the plasma for an extended period of time. As part of the development of the RPA, the complementary DNA (cDNA) sequence for fathead minnow VTG was determined and the deduced amino acid sequence compared with VTG sequences for other fish species.

Korte, J.J.; Kahl, M.D.; Jensen, K.M.; Pasha, M.S.; Parks, L.G.; LeBlanc, G.A.; Ankley, G.T.

2000-04-01

19

[Effect of 17beta-estradiol on mRNA expression of Bax proapoptotic protein and DNA fragmentation level in the human adrenal cortex].  

PubMed

The effect of 17beta-estradiol on the change of proapoptotic protein Bax mRNA level and DNA laddering in human adrenal cortex tissue was studied. The adding of 17beta-estradiol to incubation medium caused a decrease of the proapoptotic protein Bax mRNA level in adrenocorticocytes by 22% in comparison with control. Hormone influence decreases the DNA fragmentation by 50%. The obtained data suggest that 17beta-estradiol caused a significant antiapoptotic effect in human adrenal cortex. PMID:19873880

Tron'ko, M D; Kovzun, O I; Hrinchenko, Ie M; Mykosha, O S

2009-01-01

20

90-day feeding and one-generation reproduction study in Crl:CD BR rats with 17 beta-estradiol.  

PubMed

Over the past several years, there has been increasing concern that chemicals and pesticides found in the environment may mimic endogenous estrogens, potentially producing adverse effects in wildlife and human populations. Because estrogenicity is one of the primary concerns, a 90-day/one-generation reproduction study with 17 beta-estradiol was designed to set dose levels for future multigenerational reproduction and combined chronic toxicity/oncogenicity studies. The purpose of these studies is to evaluate the significance of a range of responses as well as to provide benchmark data for a risk assessment for chemicals with estrogen-like activities. This 90-day/one-generation reproduction study was conducted in male and female Crl:CD BR rats using dietary concentrations of 0, 0.05, 2.5, 10, and 50 ppm 17 beta-estradiol. Endpoints were chosen in order to evaluate both subchronic and reproductive toxicity. In addition, several mechanistic/biochemical endpoints were evaluated for their usefulness in follow-up studies. In the P1 generation, dietary administration of 2.5, 10, and 50 ppm 17 beta-estradiol produced dose-dependent decreases in body weight, body weight gain, food consumption, and food efficiency. At 10 and 50 ppm 17 beta-estradiol, minimal to mild nonregenerative anemia, lymphopenia, decreased serum cholesterol (50 ppm only), and altered splenic lymphocyte subtypes were also observed in the P1 generation. Additionally, at these concentrations, there were changes in the weights of several organs. Evidence of ovarian malfunction, characterized by reduced numbers of corpora lutea and large antral follicles, was observed at 2.5 ppm 17 beta-estradiol and above. Other pathologic changes in males and females fed 10 and 50 ppm 17 beta-estradiol included centrilobular hepatocellular hypertrophy; diffuse hyperplasia of the pituitary gland; feminization of the male mammary glands; mammary gland hyperplasia in females; increased number of cystic follicles in the ovary; hypertrophy of the endometrium and endometrial glands in the uterus; degeneration of seminiferous epithelium; and atrophy of the testes and the accessory sex glands. In the reproduction portion of this study, rats fed 10 or 50 ppm 17 beta-estradiol did not produce litters. While there was no evidence that the 50 ppm treated rats mated, 33.3% of the rats fed 10 ppm mated but did not produce litters. No effects on mating and fertility indices were observed in rats fed 0.05 and 2.5 ppm 17 beta-estradiol. Pup weights at birth were statistically decreased relative to control in the groups fed 0.05 and 2.5 ppm 17 beta-estradiol. Weights of the rats in the 0.05 ppm group recovered by postnatal day 4 and remained similar to control throughout the remainder of the study. The mean gestation length of the 0.05 ppm group was slightly, albeit not statistically significantly, shorter (0.5 days) than that of the control group, which may have contributed to the decrease in birth weight of the 0.05 ppm group. In contrast, the weights of the F1 generation rats fed 2.5 ppm 17 beta-estradiol remained decreased relative to the control group throughout the study. Parental administration of 17 beta-estradiol did not alter anogenital distance in male or female pups. The onset of sexual maturation, as measured by day of preputial separation in males and day of vaginal opening in females, was delayed in male rats fed 2.5 ppm (by 8.2 days) and was hastened in female rats fed 0.05 and 2.5 ppm (by 1.6 and 8.8 days, respectively). The age at vaginal opening ranged from 26 to 37, 26 to 35, and 21 to 25 days for rats fed 0, 0.05, and 2.5 ppm 17 beta-estradiol, respectively. Hence, the range of age at vaginal opening was similar between the control and 0.05 ppm group. The organ weight and pathologic alterations observed in the adult F1 generation rats were similar to those observed in the P1 generation rats. (ABSTRACT TRUNCATED) PMID:9742652

Biegel, L B; Flaws, J A; Hirshfield, A N; O'Connor, J C; Elliott, G S; Ladics, G S; Silbergeld, E K; Van Pelt, C S; Hurtt, M E; Cook, J C; Frame, S R

1998-08-01

21

Effects of 17beta-estradiol on blood-brain barrier disruption during focal cerebral ischemia in younger and older rats.  

PubMed

This study was performed to compare the effects of 17beta-estradiol on blood-brain barrier disruption in focal cerebral ischemia between younger and older rats. Younger (three-month-old) and older (24-month-old) ovariectomized female Fischer 344 rats were studied. In one half of each age group, a 500 microg 17beta-estradiol 21-day release pellet and in another half, a vehicle pellet was implanted 21 days before the experiments. One hour after middle cerebral artery occlusion, the transfer coefficient (Ki) of 14C-alpha-aminoisobutyric acid and the volume of 3H-dextran distribution were determined to examine the degree of blood-brain barrier disruption. In all four groups, the Ki in the ischemic cortex was higher than in the corresponding contralateral cortex. There was no significant difference in the Ki in both cortices among the groups. The volume of dextran distribution of the ischemic cortex was only greater than in the corresponding contralateral cortex in the older 17beta-estradiol-treated group, and the volume of that group was greater than the younger 17beta-estradiol-treated group (4.00 +/- 1.29 VS. 2.13 +/- 0.88 ml/100 g). After analyzing the difference in Ki between the ischemic cortex and the contralateral cortex in each animal, the difference was significantly greater in the older 17beta-estradiol-treated rats than the older vehicle-treated rats (3.40 +/- 2.10 VS. 1.26 +/- 1.44 microl/g/min). In the younger rats, however, 17beta-estradiol did not significantly affect the difference. Our data showed that 17beta-estradiol treatment failed to attenuate the BBB disruption in the cerebral ischemic cortex in the older or younger Fischer 344 rats. However, our data also suggest the possibility that 17beta-estradiol could aggravate the BBB disruption in older rats. PMID:16823719

Chi, O Z; Hunter, C; Liu, X; Weiss, H R

2006-06-01

22

Rapid vascular escape of arterially injected 16alpha-radioiodo, 17beta-estradiol  

SciTech Connect

The authors undertook this study because confirmation of a rapid vascular escape and slow release back into the circulatory system suggests that arterial injection of radiohalogenated steroid receptor ligands might provide an efficacious route of administration for imaging or treatment of receptor-rich malignant tumors in peripheral tissues. The authors injected radiolabeled 16alpha-iodo, 17beta-estradiol ([I]-E) into the femoral artery of swine in a solution that contained [[sup 125]I]-E in a known ratio to [[sup 99]Tc]-labeled red blood cells. Fractions of femoral venous blood were collected at short intervals during 10 min. They looked for changes in the ratio of the radiolabeles. [[sup 99m]Tc]-labeled red blood cells are known to remain in the vascular system for an hour or more. After passage of the injectate through the capillary bed of the swine leg, a dramatic decrease of the initial [sup 125]I:[sup 99m]Tc ratio to only 10% was observed in the femoral venous blood. This ratio increased gradually during the next 10 min to approximately 30% of that in the injectate, indicating that a significant portion (approximately 90%) of the [[sup 125]I]-E was initially trapped in the limb and then slowly re-entered the vascular system. To obtain visual confirmation of the rapid vascular escape of iodo-estrogen, they injected either an imageable form of [I]-E ([[sup 123]I]-E) or [[sup 99m]Tc]-labeled red blood cells into the dorsal aorta of superovulated rabbits, whose smaller size allowed whole-body imaging. The biodistributions of these radiopharmaceuticals were surveyed continuously by real-time planar gamma imaging. A large fraction of [I]-E escapes from the vascular system during the first pass through an organ or limb, without regard to the estrogen receptor content of the tissue. 28 refs., 3 figs., 1 tab.

Scharl, A.; Holt, J.A. (Univ. of Chicago, IL (United States))

1993-03-20

23

17beta-estradiol promotes the synthesis and the secretion of annexin I in the CCRF-CEM human cell line.  

PubMed Central

AIMS: Annexin I (ANXA1), a 37kDa member of the annexin family of Ca2+-binding and phospholipid-binding proteins, is particularly abundant in various populations of peripheral blood leukocytes. Since this protein modulates the anti-inflammatory actions of the steroid hormones, the purpose of this study was to investigate the effects of the female sex steroid hormone, 17beta-estradiol (E2beta), on the synthesis and secretion of ANXA1 in the human CCRF-CEM acute lymphoblastic leukemia cell line. METHODS: Complementary reverse transcription-polymerase chain reaction and Western blot assays were performed to study the effect of E2beta on the expression of mRNA and protein ANXA1, respectively. RESULTS AND DISCUSSION: Treatment of CCRF-CEM cells with E2beta, for 30 min, stimulated the synthesis of ANXA1 mRNA molecules, and increased the cellular level of ANXA1 protein. Moreover, when the cells were incubated with E2beta under the same experimental conditions, a significant increase in the amount of ANXA1 secreted from the cells was also detected. ICI 182,780, a selective inhibitor of the intracellular estrogen receptor, had no effect on the E2beta-stimulated expression and externalisation of ANXA1. Taken together, these results indicate that E2beta induces de novo synthesis of ANXA1 and stimulates its secretion in the CCRF-CEM cell line, apparently through a mechanism independent of the intracellular estrogen receptor. PMID:11759108

Castro-Caldas, M; Duarte, C B; Carvalho, A R; Lopes, M C

2001-01-01

24

Gender-related effects of 17-{beta}-estradiol and B-hexachlorocyclohexane on liver tumor formation in medaka (Oryzias latipes)  

SciTech Connect

When medaka were acutely exposed to diethylnitrosamine (DEN), greater incidence of hepatocarcinoma was seen in female versus male fish. This is possibly related to elevated female endogenous estrogens, which increase liver weight and production of vitellogenin. To examine roles of estrogens in tumor modulation, 21-day old medaka were exposed to DEN (200 ppm for 24 hr.), then fed purified diets containing the estrogenic compound {beta}-hexachlorocyclohexane ({beta}-HCH) or 17-{beta}estradiol (E2) for 6 months. Incidences of basophilic preneoplastic foci of cellular alteration in females receiving DEN and 0.01, 0.1, or 1.0 ppm E2 were three times the incidences in similarly-treated males. Also, incidences of basophilic foci in DEN + 0.1 ppm E2 males were significantly increased over DEN-only males and were equal to incidences in DEN-only females. Liver weights and hepatosomatic indices of males given 0.1 ppm E2 were not significantly different than females fed control diet. Females fed 0.01-10.0 ppm {beta}-HCH after DEN had 4--5 times greater incidences of basophilic foci as males. Gender-related effects on kinetics of growth rates and volumes of foci are being examined.

Cooke, J.B.; Hinton, D.E. [Univ. of California, Davis, CA (United States)

1994-12-31

25

17 beta-Estradiol metabolism by hamster hepatic microsomes. Implications for the catechol-O-methyl transferase-mediated detoxication of catechol estrogens.  

PubMed

We have shown that the metabolism of 17 beta-estradiol in hamster liver microsomes is concentration-dependent. At low (< 25 microM) concentrations of 17 beta-estriol, 16 alpha-hydroxylase activity predominated, and estriol was the major metabolite. At higher concentrations (25-75 microM), 16 alpha-hydroxylation and aromatic hydroxylation at C2 contributed equally to 17 beta-estradiol metabolism. Aromatic C4-hydroxylation was maximal at 75 microM of 17 beta-estradiol and was always less than C2-hydroxylation. Dehydrogenation of the 17 beta-hydroxyl group to the ketone (estrone) was also observed, but both estrone and 2-hydroxyestrone were minor (approximately 3%) metabolites of 17 beta-estradiol, only detectable at concentrations of 50 microM and above. Catechol-O-methyl transferase (COMT) effectively converted both 2- and 4-hydroxyl-17 beta-estradiol to their corresponding monomethoxy metabolites. Effective reducing conditions are required for COMT activity, because catechol estrogens are readily oxidized to their corresponding ortho-quinones, and ascorbic acid is routinely added to assays of COMT activity. Interestingly, although ascorbic acid (1 mM) increased the recovery of 2- and 4-hydroxy-17 beta-estradiol from microsomal incubations, it decreased the recovery of the methoxy metabolites (approximately 40%). Since the enediol function of ascorbate resembles that of a catechol group, ascorbate is a substrate for COMT and probably competes with the catechol estrogens for methylation. Because previous studies describing the ability of COMT to inhibit the covalent binding of electrophilic reactive metabolites of [4-(14)C]17 beta-estradiol to microsomal protein were performed in the presence of high (100 mM) Mg2+ concentrations, we also investigated the effects of Mg2+ on 17 beta-estradiol metabolism. Concentrations of Mg2+ > 10 mM inhibited the metabolism of 17 beta-estradiol, as evidenced by i) the increased recovery of substrate; ii) a decrease in the formation of estriol, estrone, and 2-, and 4-hydroxy-17 beta-estradiol; iii) a decrease in the recovery of water-soluble metabolites when incubations were performed in the presence of glutathione (GSH) to trap the reactive electrophilic metabolites; and iv) a decrease in the amount of reactive electrophilic metabolites bound to microsomal protein. GSH also decreased the covalent binding of electrophilic metabolites of [4-(14)C]17 beta-estradiol to microsomal protein, with the concomitant formation of water-soluble metabolites. Thus, both COMT and GSH combine to limit the formation of electrophilic metabolites from 17 beta-estradiol. The relative importance of each of these pathways to the disposition of the catechol estrogens remains to be determined. PMID:8723741

Butterworth, M; Lau, S S; Monks, T J

1996-05-01

26

The role of beta 2-adrenergic vascular receptors in the peripheral vasodilation caused by 17 beta-estradiol in anesthetized pigs.  

PubMed

It has been previously shown in anesthetized pigs that intravenous infusion of 2 microg/h of 17beta-estradiol primarily dilated renal, iliac and coronary circulations, while higher doses of the hormone were required to cause vasodilation also in the mesenteric vascular bed. In the same experimental model, a tonic beta2-adrenoceptor mediated vasodilation, which could be argued to attenuate the vasodilator effect of 17beta-estradiol, has been described. The present study was planned to investigate the role of beta2-adrenergic receptors in the hemodynamic responses of renal and mesenteric vascular beds to 17beta-estradiol. Changes in flow caused by intravenous infusion of 2 microg/h of the hormone at constant heart rate and aortic blood pressure in the left renal and superior mesenteric arteries were assessed using electromagnetic flowmeters. In six pigs, infusion of 17beta-estradiol caused an increase in renal blood flow, which averaged 12.1% of the control values, without affecting mesenteric blood flow. In the same pigs, after hemodynamic variables had returned to the baseline values, blockade of beta2-adrenergic receptors with butoxamine caused an increase in aortic blood pressure and an increase in renal and mesenteric resistance. The subsequent infusion of 17beta-estradiol elicited increases in renal and mesenteric blood flow which respectively averaged 19.6% and 12.8%. Therefore, the present study in anesthetized pigs have shown that the vasodilator responses of the renal and mesenteric circulations to 17beta-estradiol were attenuated and even masked by a tonic beta2-adrenoceptor mediated vasodilation. This indicates that some vasodilator effects elicited by normally used replacement doses of the hormone may not be apparent. PMID:10574220

Molinari, C; Battaglia, A; Grossini, E; Mary, D A; Surico, N; Vacca, G

1999-01-01

27

Larval exposure to 4-nonylphenol and 17beta-estradiol affects physiological and behavioral development of seawater adaptation in Atlantic salmon smolts.  

PubMed

Population declines of anadromous salmonids are attributed to anthropogenic disturbances including dams, commercial and recreational fisheries, and pollutants, such as estrogenic compounds. Nonylphenol (NP), a xenoestrogen, is widespread in the aquatic environment due to its use in agricultural, industrial, and household products. We exposed Atlantic salmon yolk-sac larvae to waterborne 10 or 100 microg L(-1) NP (NP-L or NP-H, respectively), 2 microg L(-1) 17beta-estradiol (E2), or vehicle, for 21 days to investigate their effects on smolt physiology and behavior 1 year later. NP-H caused approximately 50% mortality during exposure, 30 days after exposure, and 60 days after exposure. Mortality rates of NP-L and E2 fish were not affected until 60 days after treatment, when they were 4-fold greater than those of controls. Treatment with NP-L or E2 as yolk-sac larvae decreased gill sodium-potassium-activated adenosine triphosphatase (Na+,K(+)-ATPase) activity and seawater (SW) tolerance during smolt development, 1 year after exposure. Exposure to NP-L and E2 resulted in a latency to enter SW and reduced preference for SW approximately 2- and 5-fold, respectively. NP-L-exposed fish had 20% lower plasma insulin-like growth factor I (IGF-I) levels and 35% lower plasma triiodothyronine (T3). Plasma growth hormone and thyroxine (T4) were unaffected. Exposure to E2 did not affect plasma levels of IGF-I, GH, T3, or T4. Both treatment groups exhibited increased plasma cortisol and decreased osmoregulatory capacity in response to a handling stressor. These results suggest that early exposure to environmentally relevant concentrations of NP, and other estrogenic compounds, can cause direct and delayed mortalities and that this exposure can have long-term, "organizational" effects on life-history events in salmonids. PMID:17626455

Lerner, Darren T; Björnsson, Björn Thrandur; McCormick, Stephen D

2007-06-15

28

Modulation of 17{beta}-estradiol-induced responses in fish by cytochrome P4501A1 inducing compounds  

SciTech Connect

Some compounds which induce cytochrome P4501A1 (CYP1A1) are antiestrogenic in mammalian bioassay, and this effect is linked to aryl hydrocarbon (Ah) receptor. Liver of fish synthesizes estrogen-inducible egg yolk precursor protein vitellogenin (Vg) which is critical for oocyte maturation and ovarian development. To determine if Ah receptor-linked endocrine modulation could occur in fish liver, primary cultures of juvenile rainbow trout (Oncorhynchus mykiss) liver cells were co-administered 17{beta}-estradiol and CYP1A1 inducing compounds. Vitellogenin and albumin, estimated by ELISA measurement of concentration in the media 48 hrs after treatment, formed the basis for the test. Cellular CYP1A1 protein content and catalytic activity was estimated by ELISA and ethoxyresorufin-O-deethylase (EROD) activity assays respectively. Equivalent viability (mitochondrial dehydrogenase activity) and secretary functional capacity (albumin synthesis) were estimated and correlated with other results. In descending order, 2,3,4,7,8 pentachlorodibenzofuran (10{sup {minus}12} to 10{sup {minus}8} M) > 2,3,7,8 tetrachlorodibenzo-p-dioxin {approx_equal} 2,3,7,8 tetrachlorodibenzofuran (10{sup {minus}11} to 10{sup {minus}8} M) > {beta}-naphthoflavone (10{sup {minus}7} to 10{sup {minus}6} M) inhibited Vg synthesis in 17{beta}-estradiol treated liver cells. Potency of inhibition directly related to strength as an inducer of CYP1A1 protein. At 10-8 M, PCB congeners 77, 126, and 156 did not inhibit Vg synthesis and induced no or only moderate CYP1A1 protein. At 10-8 M, PCB congener 114, a weak CYP1A1 inducer, potentiated Vg synthesis relative to cells treated with 17{beta}-estradiol alone. This study increases their understanding of the consequences of hepatic CYP1A1 induction, forewarns of reproductive impairment of sexually maturing fishes exposed to CYP1A1 inducing compounds and argues for further, more detailed in vivo investigation.

Anderson, M.J.; Hinton, D.E. [Univ. of California, Davis, CA (United States)

1995-12-31

29

17 beta-estradiol modifies nitric oxide-sensitive guanylyl cyclase expression and down-regulates its activity in rat anterior pituitary gland.  

PubMed

Previous studies showed that 17 beta-estradiol (17 beta-E2) regulates the nitric oxide (NO)/soluble guanylyl cyclase (sGC)/cGMP pathway in many tissues. Evidence from our laboratory indicates that 17 beta-E2 disrupts the inhibitory effect of NO on prolactin release, decreasing sGC activity and affecting the cGMP pathway in anterior pituitary gland of adult ovariectomized and estrogenized rats. To ascertain the mechanisms by which 17 beta-E2 affects sGC activity, we investigated the in vivo and in vitro effects of 17 beta-E2 on sGC protein and mRNA expression in anterior pituitary gland from immature female rats. In the present work, we showed that 17 beta-E2 acute treatment exerted opposite effects on the two sGC subunits, increasing alpha1 and decreasing beta1 subunit protein and mRNA expression. This action on sGC protein expression was maximal 6-9 h after 17 beta-E2 administration. 17beta-E2 also caused the same effect on mRNA expression at earlier times. Concomitantly, 17 beta-E2 dramatically decreased sGC activity 6 and 9 h after injection. These effects were specific of 17 beta-E2, because they were not observed with the administration of other steroids such as progesterone and 17 alpha-estradiol. This inhibitory action of 17beta-E2 on sGC also required the activation of estrogen receptor (ER), because treatment with the pure ER antagonist ICI 182,780 completely blocked 17 beta-E2 action. 17 beta-E2 acute treatment caused the same effects on pituitary cells in culture. These results suggest that 17 beta-E2 exerts an acute inhibitory effect on sGC in anterior pituitary gland by down-regulating sGC beta 1 subunit and sGC activity in a specific, ER-dependent manner. PMID:16740976

Cabilla, Jimena P; Díaz, María del Carmen; Machiavelli, Leticia I; Poliandri, Ariel H; Quinteros, Fernanda A; Lasaga, Mercedes; Duvilanski, Beatriz H

2006-09-01

30

[The modelling of N-stearoylethanolamine effect of 17beta-estradiol in the organism of male rats].  

PubMed

The influence of N-stearoylethanolamine (NSE) on total 11-hydroxycorticosteroids (11-HCS) and testosterone level in the blood of male rats in normal conditions and under the action of 17beta-estradiol (400 mkg/kg of body weight during 3 days) was studied. It was shown that NSE administration per os (50 mg/kg of body weight during 7 days) to intact animals did not change the level of 11-HCS and of testosterone. The administration of NSE to estrogenized male rats decreased the elevated level of 11-HCS and normalized the amount of testosterone in blood. The correction of alterated weight of adenohypophysis and testis of estrogenized male rats compared to control can be a direct evidence of NSE-mediated modelling of the effect on hypothalamic-pituitary hormone system. The effect of NSE in the testis of estrogenized male rats inhibited the process of lipid peroxidation, caused the decrease of the amount of thiobarbituric acid reactive substances and increased the activity of superoxide dismutase and catalase. The NSE showed more expressed antioxidative effect compared to vitamin E. Taking into consideration all above mentioned data we suggested that NSE administration to male rats protected Leydig cells from damage under the increase of estrogen level. PMID:21328874

Hula, N M; Shovkun, S A; Hrinchenko, Ie M; Horid'ko, T M; Berdyshev, A H; Barbot'ko, O O; Mykosha, O S

2010-01-01

31

Simultaneous detection for three kinds of veterinary drugs: Chloramphenicol, clenbuterol and 17-beta-estradiol by high-throughput suspension array technology  

Microsoft Academic Search

Suspension array technology for simultaneous detection of three kinds of veterinary drugs, chloramphenicol (CAP), clenbuterol and 17-beta-estradiol has been developed. Conjugates of chloramphenicol and clenbuterol coupled with bovine serum albumin were synthesized and purified. Probes of suspension array were constituted by coupling the three conjugates on the fluorescent microspheres\\/beads and the microstructures of the beads’ surface were observed by scanning

Nan Liu; Pu Su; Zhixian Gao; Maoxiang Zhu; Zhihua Yang; Xiujie Pan; Yanjun Fang; Fuhuan Chao

2009-01-01

32

Maternally derived testosterone and 17beta-estradiol in the eggs of Arctic-breeding glaucous gulls in relation to persistent organic pollutants.  

PubMed

It is largely unknown if and how persistent organic pollutants (POPs) affect the transfer of maternal hormones to eggs. This occurs despite an increasing number of studies relating environmental conditions experienced by female birds at the time of egg formation to maternal hormonal effects. Here we report the concentrations of maternal testosterone, 17beta-estradiol and major classes of POPs (organochlorines, brominated flame retardants and metabolically-derived products) in the yolk of unincubated, third-laid eggs of the glaucous gull (Larus hyperboreus), a top-predator in the Arctic marine environment. Controlled for seasonal and local variation, positive correlations were found between the concentrations of certain POPs and testosterone. Contaminant-related changes in the relative concentrations of testosterone and 17beta-estradiol were also observed. In addition, yolk steroid concentrations were associated with contaminant profiles describing the proportions of different POPs present in the yolk. Eggs from nests in which two sibling eggs hatched or failed to hatch differed in POP profiles and in the relative concentrations of testosterone and 17beta-estradiol. Although the results of this correlative study need to be interpreted with caution, they suggest that contaminant-related changes in yolk steroids may occur, possibly affecting offspring performance over and above toxic effects brought about by POPs in eggs. PMID:18550446

Verboven, Nanette; Verreault, Jonathan; Letcher, Robert J; Gabrielsen, Geir W; Evans, Neil P

2008-08-01

33

Effects of 17beta-estradiol on blood-brain barrier disruption in focal ischemia during GABA(A) receptor inhibition.  

PubMed

We performed this study to determine whether gamma-aminobutyric acid (GABA(A)) receptor inhibition could reverse the effect of 17beta-estradiol on blood-brain barrier (BBB) disruption in focal cerebral ischemia. Young ovariectomized rats were implanted with a 500 microg 17beta-estradiol 21-day release pellet or with a vehicle pellet 21 days before the experiments. Forty-five minutes after middle cerebral artery (MCA) occlusion, half of each group was infused with bicuculline (a GABA(A) receptor antagonist) 1 mg/kg/min for 2 min followed by 0.1 mg/kg/min up to the end of experiments. The other half was infused with the same volume of normal saline. The transfer coefficient (Ki) of 14C-alpha-aminoisobutyric acid and the volume of 3H-dextran distribution (70,000 Daltons) were determined to measure the degree of BBB disruption one hour after MCA occlusion. In the control vehicle-treated animals, the Ki in the ischemic cortex (7.2 +/- 2.6 microl/g/min) was higher than in the contralateral cortex (2.5 +/- 1.4 microl/g/min). After bicuculline infusion, the Ki in the ischemic cortex increased (10.6 +/- 5.4 microl/g/min) although the increase was not statistically significant. In the 17beta-estradiol treated animals, the Ki in the ischemic cortex (3.8 +/- 1.6 microl/g/min) was lower than control vehicle-treated rats. With bicuculline infusion, the Ki in the ischemic cortex (14.5 +/- 6.8 microl/g/min) was markedly increased. In the non-ischemic cortex, there was no significant difference in Ki among the experimental groups. The volume of dextran distribution was not significantly different between the experimental groups in the ischemic or non-ischemic cortex. Our data suggests that part of the reason for the decreased BBB disruption in the focal ischemic area after 17beta-estradiol treatment could be due to the interaction between GABA(A) receptors and 17beta-estradiol. PMID:15952079

Chi, O Z; Hunter, C; Liu, X; Weiss, H R

2005-04-01

34

Evaluation of the primary humoral immune response following exposure of male rats to 17beta-estradiol or flutamide for 15 days.  

PubMed

There is a concern that certain industrial chemicals found in the environment may mimic or antagonize endogenous hormones and adversely affect the endocrine as well as the immune system. The objective of this study was to determine if exposure of Crl:CD (SD)BR male rats to 17beta-estradiol (17beta-E2), an estrogen receptor agonist, or flutamide (FLUT), an androgen receptor antagonist, would significantly alter the primary IgM humoral immune response to sheep red blood cells (SRBC). This study was conducted in the context of a male in vivo Tier I battery designed to identify endocrine-active compounds (EACs). The Tier I male battery consists of organ weights coupled with a comprehensive hormonal assessment. Rats were dosed by the intraperitoneal route for 15 days with vehicle or 0.001, 0.0025, 0.0075, or 0.050 mg/kg/day 17beta-E2 or 0.25, 1, 5, or 20 mg/kg/day FLUT. Six days prior to termination, selected rats were injected intravenously with SRBC for assessment of humoral immune function. Spleen cell number and spleen and thymus weights were obtained. Serum was analyzed for anti-SRBC IgM antibody by using an enzyme-linked immunosorbent assay. At 0.050 mg/kg/day 17beta-E2, mean final body and absolute thymus weights were significantly decreased to 84 and 65% of control, respectively. 17beta-E2 did not significantly alter spleen weight, spleen cell number, or the primary IgM humoral immune response to SRBC. The no-observed-adverse-effect level (NOAEL) for immune system alteration was 0.050 mg/kg/day 17beta-E2 since the decrease in absolute thymus weight was judged to be secondary to the decrements in body weight. In the Tier I male battery, responses to 17beta-E2 included decreased absolute testis and epididymis weights, decreased relative accessory sex gland unit weights, hormonal alterations (decreased serum testosterone (T), dihydrotestosterone (DHT), and luteinizing hormone (LH), and increased serum prolactin and E2 levels). The lowest-observed-adverse-effect level (LOAEL) for the reproductive indices was 0.001 mg/kg/day 17beta-E2 based on the hormonal alterations seen at this level; no NOAEL was established. Exposure to FLUT did not significantly alter mean final body, spleen, or absolute thymus weights, spleen cell number, or the primary IgM humoral immune response to SRBC. A significant increase (118% of control) in relative thymus weight was observed at 20 mg/kg/day FLUT. The NOAEL for immune system alteration was 5 mg/kg/day FLUT based on the increased relative thymus weights that were judged to be compound-related. In the Tier I male battery, responses to FLUT included decreased absolute epididymis and relative accessory sex gland unit weights and hormonal alterations (increased serum T, DHT, E2, and LH, and decreased follicle stimulating hormone levels). The LOAEL for the reproductive indices was 0.25 mg/kg/day FLUT based on the hormonal alterations seen at this level; no NOAEL was established. Based on these data, the reproductive and not the immune system appears to be the primary target organ of toxicity in young adult male rats treated with either 17beta-E2 or FLUT. PMID:9928670

Ladics, G S; Smith, C; Nicastro, S C; Loveless, S E; Cook, J C; O'Connor, J C

1998-11-01

35

Regulation of beta follicle stimulating hormone subunit RNA by 17-beta estradiol, progesterone, and inhibin in ovine pituitary cells in culture  

SciTech Connect

The molecular mechanism by which ovine follicle stimulating hormone (FSH) is negatively regulated by 17-beta estradiol, progesterone, and inhibin was investigated in vitro, using ovine pituitary cells in culture. The effects of these gonadal hormones on beta FSH RNA levels were assayed by dot blot hybridization to a specific radiolabeled cDNA probe for beta FSH RNA. This was compared to concomitant changes in FSH secretion, which were measured by radioimmunoassay, in order to determine if the alterations in beta FSH RNA could account for the changes in FSH secretion.

Phillips, C.L.

1987-01-01

36

Novel estrogens and their radical scavenging effects, iron-chelating, and total antioxidative activities: 17 alpha-substituted analogs of delta 9(11)-dehydro-17 beta-estradiol.  

PubMed

Antioxidant effects of N,N-dimethyl-p-toluidine, p-cresol, and p-(hydroxy)thioanisol 17 alpha-substituted analogs of 17 beta-estradiol and their delta 9(11)-dehydro homologs were investigated using four different in vitro models: rat synaptosomal lipid peroxidation induced by Fenton's reagent, Fe(II)-chelating activities, the formation of superoxide anion radicals, and total antioxidative activity. Whereas the classical estrogen 17 beta-estradiol as well as selected phenolic compounds was only moderately inhibiting iron-dependent lipid peroxidation and stimulating total antioxidative activity, besides delta 9(11)-dehydro-17 beta-estradiol (J 1213), novel estrogens such as C-17-oriented side chain analogs of 17 beta-estradiol (J 843, J 872, and J 897) and delta 9(11)-dehydro homologs (J 844, J 864, and J 898) directly altered the iron redox chemistry and diminished the formation of superoxide anion radicals generated by a xanthine/xanthine oxidase-dependent luminescence reaction to a great extent. These results suggest that definite modifications in the chemical structure of 17 beta-estradiol, e.g., the introduction of a delta 9(11)-double bond and/or p-cresol as well as p-(hydroxy)thioanisol C-17 substitution, may result in substantial changes in their antioxidant behavior. These compounds may be drug candidates for treating pathologies related to free radical formation. PMID:9366006

Römer, W; Oettel, M; Menzenbach, B; Droescher, P; Schwarz, S

1997-11-01

37

17Beta-estradiol protects against oxidative stress-induced cell death through the glutathione/glutaredoxin-dependent redox regulation of Akt in myocardiac H9c2 cells.  

PubMed

The GSH/glutaredoxin (GRX) system is involved in the redox regulation of certain enzyme activities, and this system protects cells from H2O2-induced apoptosis by regulating the redox state of Akt (Murata, H., Ihara, Y., Nakamura, H., Yodoi, J., Sumikawa, K., and Kondo, T. (2003) J. Biol. Chem. 278, 50226-50233). Estrogens, such as 17beta-estradiol (E2), play an important role in development, growth, and differentiation and appear to have protective effects on oxidative stress mediated by estrogen receptor alpha (ERalpha). However, the role of the ERbeta-mediated pathway in this cytoprotection and the involvement of E2 in the redox regulation are not well understood. In the present study, we demonstrated that E2 protected cardiac H9c2 cells, expressing ERbeta from H2O2-induced apoptosis concomitant with an increase in the activity of Akt. E2 induced the expression of glutaredoxin (GRX) as well as gamma-glutamylcysteine synthetase, a rate-limiting enzyme for the synthesis of GSH. Inhibitors for both gamma-glutamylcysteine synthetase and GRX and ICI182,780, a specific inhibitor of ERs, abolished the protective effect of E2 on cell survival as well as the activity of Akt, suggesting that ERbeta is involved in the cytoprotection and redox regulation by E2. Transcription of the GRX gene was enhanced by E2. The promoter activity of GRX was up-regulated by an ERbeta-dependent element. These results suggest that the GRX/GSH system is involved in the cytoprotective and genomic effects of E2 on the redox state of Akt, a pathway that is mediated, at least in part, by ERbeta. This mechanism may also play an antiapoptotic role in cancer cells during carcinogenesis or chemotherapy. PMID:16549430

Urata, Yoshishige; Ihara, Yoshito; Murata, Hiroaki; Goto, Shinji; Koji, Takehiko; Yodoi, Junji; Inoue, Satoshi; Kondo, Takahito

2006-05-12

38

Analysis of gene expression profiles in largemouth bass exposed to 17-beta-estradiol and to anthropogenic contaminants that behave as estrogens.  

PubMed

Novel molecular based methods are being developed to study changes in gene expression in wildlife exposed to anthropogenic chemicals. Gene arrays, in particular, are useful tools that can be used to simultaneously monitor hundreds to thousands of genes within a single experiment, giving an investigator the ability to determine how exposure affects multiple metabolic pathways. These methods are thought to be both sensitive and able to reveal biochemical mechanisms of action. A largemouth bass (LMB) array containing 132 genes has been designed to study the impact of gene expression in male fish exposed to 17-beta estradiol or to the compounds 4-nonylphenol (4-NP) or 1,1-dichloro-2, 2-bis (p-chlorophenyl) ethylene (p,p'-DDE). The results of these experiments demonstrate distinct gene expression patterns in LMB exposed to these compounds. PMID:14680325

Larkin, P; Sabo-Attwood, T; Kelso, J; Denslow, N D

2003-12-01

39

Effect of 17 beta-estradiol, retinoic acid and tamoxifen upon primary and transplanted thyroid tumor in B6C3F1 mice fed an iodine deficient diet.  

PubMed

This study was aimed to establish TSH dependent, transplantable thyroid tumor (TT) in B6C3F1 (BCF1) mice. In addition, transplanted TT was examined for its growth in mice given 17 beta-estradiol (E2), retinoic acid (RA), tamoxifen (TAM), T3 and T4. Both sexes of BCF1 mice were observed for 12 months under IDD and distilled water (DW), starting at 4 weeks of age. Groups of mice received an i.p. injection of radioactive iodine (131I) once at a dose of 60 mu Ci/head and/or given 0.25 mg E2 pellet s.c. One piece of induced pituitary or thyroid tumor was individually dissected aseptically and s.c. grafted under the fat pad of one site of the neck in the same strain of mice at 5 weeks of age. All mice were sacrificed between 7.5 to 13.5 months after grafting the tumors depending on the experiments. The transplantability of both pituitary and thyroid tumor was 100% in IDD mice, but TT was about 50% with a combined treatment of IDD plus E2. A supplement of thyroid hormones of T3 or T4 in mice with IDD completely inhibited the growth of in situ or grafted thyroid tumors. The growth of in situ thyroid gland was significantly promoted by the oral administration of RA in both sexes, whereas the growth of transplanted TT was significantly increased by RA in the female, but not in the male. Oral administration of TAM proved inhibitory upon in in situ and transplanted TT in the male, but not in the female. Thyroid tumor induced by IDD could grow only in mice with IDD and was partially regulated of its growth by RA and TAM. PMID:9538564

Roy, G; Nakatani, T; Goto, T; Fujimoto, N; Ito, A

1997-12-01

40

17beta-estradiol regulates constitutive nitric oxide synthase expression differentially in the myocardium in response to pressure overload.  

PubMed

Estrogens [E(2)] exert direct and indirect effects that can modulate the development of cardiac disease. However, the precise mechanisms that are involved remain undefined. Our objective was to investigate whether E(2) affected the activity and expression of constitutive nitric oxide synthase (NOS) isoforms (NOS3 and NOS1) in cardiac hypertrophy induced by thoracic aortic constriction (TAC). Ovariectomized (Ovx) and nonovariectomized Wistar rats were subjected to TAC. Ovx animals received E(2) or placebo 3 wk after surgery for 11 wk. Afterward cardiac function and degree of left ventricular hypertrophy were assessed by echocardiography. NOS activity and expression were studied by biochemical techniques. TAC led to significant left ventricular hypertrophy (>90%) irrespective of hormonal status. Cardiac performance declined more in TAC+Ovx (-20%, P < 0.015) than in the two other TAC groups [TAC and TAC+Ovx+E(2)]. Total NOS activity decreased significantly in the Ovx groups. In response to TAC, total NOS activity increased whatever the E(2) status. Specific NOS3 activity dramatically decreased in the Ovx groups (-55%, P < 0.009) and was unaltered by TAC. By using coimmunoprecipitation assays, we showed that NOS3/caveolin-1 complexes negatively regulated NOS3 activity as a function of E(2) status. On the other hand, NOS1 expression and activity were markedly increased in hypertrophied myocardium (P < 0.003), irrespective of E(2) status. This study demonstrates a differential regulation of NOS expression and activity in response to pressure overload and E(2) status, the former being mainly involved in the induction of NOS1, whereas the latter regulated NOS3 activity and in turn cardiac function. PMID:17673519

Loyer, Xavier; Damy, Thibaud; Chvojkova, Zuzana; Robidel, Estelle; Marotte, Françoise; Oliviero, Patricia; Heymes, Christophe; Samuel, Jane-Lise

2007-10-01

41

Identification of centrarchid hepcidins and evidence that 17beta-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides).  

PubMed

Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormone. Both hepcidins are predominately expressed in the liver of largemouth bass, similar to other fish and mammals. Experimental exposure of pond-raised largemouth bass to 17beta-estradiol and/or the bacteria Edwardsiella ictaluri led to distinct changes in expression of hep-1 and hep-2. Estradiol reduced the constitutive expression of hep-1 in the liver. Bacterial exposure induced expression of hep-2, suggesting that hepcidin-2 may have an antimicrobial function, and this induction was abolished by estradiol. To our knowledge, this is the first report of the regulation of hepcidin expression by estradiol in either fish or mammals. PMID:19376234

Robertson, Laura S; Iwanowicz, Luke R; Marranca, Jamie Marie

2009-06-01

42

PLASMA CLEARANCE OF VITELLOGENIN IN SHEEPSHEAD MINNOWS AFTER CESSATION OF EXPOSURE TO 17BETA-ESTRADIOL AND PARA-NONYLPHENOL  

EPA Science Inventory

Two experiments were performed to determine the rate of vitellogenin plasma accumulation and clearance in male sheepshead minnows (Cyprinodon variegatus) during and after exposure to either 17b-estradiol (E2) or para-nonylphenol (p-NP). Adult fish were continuously exposed to aqu...

43

Rainfall and tillage effects on transport of fecal bacteria and sex hormones 17beta-estradiol and testosterone from broiler litter applications to a Georgia Piedmont Ultisol.  

PubMed

Poultry litter provides nutrients for crop and pasture production; however, it also contains fecal bacteria, sex hormones (17beta-estradiol and testosterone) and antibiotic residues that may contaminate surface waters. Our objective was to quantify transport of fecal bacteria, estradiol, testosterone and antibiotic residues from a Cecil sandy loam managed since 1991 under no-till (NT) and conventional tillage (CT) to which either poultry litter (PL) or conventional fertilizer (CF) was applied based on the nitrogen needs of corn (Zea mays L) in the Southern Piedmont of NE Georgia. Simulated rainfall was applied for 60 min to 2 by 3-m field plots at a constant rate in 2004 and variable rate in 2005. Runoff was continuously measured and subsamples taken for determining flow-weighted concentrations of fecal bacteria, hormones, and antibiotic residues. Neither Salmonella, nor Campylobacter, nor antimicrobial residues were detected in litter, soil, or runoff. Differences in soil concentrations of fecal bacteria before and after rainfall simulations were observed only for Escherichia coli in the constant rainfall intensity experiment. Differences in flow-weighted concentrations were observed only for testosterone in both constant and variable intensity rainfall experiments, and were greatest for treatments that received poultry litter. Total loads of E. coli and fecal enterococci, were largest for both tillage treatments receiving poultry litter for the variable rainfall intensity. Load of testosterone was greatest for no-till plots receiving poultry litter under variable rainfall intensity. Poultry litter application rates commensurate for corn appeared to enhance only soil concentrations of E. coli, and runoff concentrations of testosterone above background levels. PMID:18571694

Jenkins, Michael B; Truman, Clint C; Siragusa, Gregory; Line, Eric; Bailey, J Stan; Frye, Jonathan; Endale, Dinku M; Franklin, Dorcas H; Schomberg, Harry H; Fisher, Dwight S; Sharpe, Ronald R

2008-09-15

44

An SPME-GC-MS method using an octadecyl silica fibre for the determination of the potential angiogenesis modulators 17beta-estradiol and 2-methoxyestradiol in culture media.  

PubMed

A simple and easily automable method based on solid-phase microextraction followed by gas chromatographic-mass spectrometric analysis was developed for the determination of two potential angiogenesis modulators 17beta-estradiol (17-BE) and 2-methoxyestradiol (2-MEOE) in culture media. Trifluoroacetic anhydride was used as the derivatising agent. A homemade octadecyl silica coating, characterised by a coating thickness of 72 +/- 10 microm and a good thermal stability until 250 degrees C, was prepared. Experimental design was used to optimise the extraction conditions in terms of derivatisation time, derivatisation temperature and time of extraction. As for method validation, lower limits of quantification of 0.17 and 0.015 microg/l for 17beta-estradiol and 2-methoxyestradiol, respectively, were obtained. Finally, the capabilities of the developed fibres were evaluated for the analysis of the investigated analytes developed by granulosa cells in culture media maintained under normoxic, hypoxic and anoxic conditions, in order to better elucidate their possible role in the angiogenic process. An increase of the production of both 17-BE and 2-MEOE in hypoxic and anoxic conditions seems to be related to the effect of oxygen deprivation. PMID:20186539

Bianchi, Federica; Mattarozzi, Monica; Careri, Maria; Mangia, Alessandro; Musci, Marilena; Grasselli, Francesca; Bussolati, Simona; Basini, Giuseppina

2010-04-01

45

Environmental Technology Verification Report for Abraxis 17ß-Estradiol (E2) Magnetic Particle Enzyme-Linked Immunosorbent Assay (ELISA) Test Kits  

EPA Science Inventory

The EPA's National Risk Management Research Laboratory (NRMRL) and its verification organization partner, Battelle, operate the Advanced Monitoring Systems (AMS) Center under ETV. The AMS Center recently evaluated the performance of the Abraxis 17(beta)-estradiol (E2) magnetic p...

46

Divergent effects of 17-{beta}-estradiol on human vascular smooth muscle and endothelial cell function diminishes TNF-{alpha}-induced neointima formation  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer TNF-{alpha} augments neointimal hyperplasia in human saphenous vein. Black-Right-Pointing-Pointer TNF-{alpha} induces detrimental effects on endothelial and smooth muscle cell function. Black-Right-Pointing-Pointer Estradiol exerts modulatory effects on TNF-induced vascular cell functions. Black-Right-Pointing-Pointer The modulatory effects of estradiol are discriminatory and cell-type specific. -- Abstract: Coronary heart disease (CHD) is a condition characterized by increased levels of proinflammatory cytokines, including tumor necrosis factor-{alpha} (TNF-{alpha}). TNF-{alpha} can induce vascular endothelial cell (EC) and smooth muscle cell (SMC) dysfunction, central events in development of neointimal lesions. The reduced incidence of CHD in young women is believed to be due to the protective effects of estradiol (E2). We therefore investigated the effects of TNF-{alpha} on human neointima formation and SMC/EC functions and any modulatory effects of E2. Saphenous vein (SV) segments were cultured in the presence of TNF-{alpha} (10 ng/ml), E2 (2.5 nM) or both in combination. Neointimal thickening was augmented by incubation with TNF-{alpha}, an effect that was abolished by co-culture with E2. TNF-{alpha} increased SV-SMC proliferation in a concentration-dependent manner that was optimal at 10 ng/ml (1.5-fold increase), and abolished by E2 at all concentrations studied (1-50 nM). Surprisingly, E2 itself at low concentrations (1 and 5 nM) stimulated SV-SMC proliferation to a level comparable to that of TNF-{alpha} alone. SV-EC migration was significantly impaired by TNF-{alpha} (42% of control), and co-culture with E2 partially restored the ability of SV-EC to migrate and repair the wound. In contrast, TNF-{alpha} increased SV-SMC migration by 1.7-fold, an effect that was completely reversed by co-incubation with E2. Finally, TNF-{alpha} potently induced ICAM-1 and VCAM-1 expression in both SV-EC and SV-SMC. However there was no modulation by E2 in either cell-type. In conclusion, TNF-{alpha} induced SV neointima formation, increased SMC proliferation and migration, impaired SV-EC migration and increased expression of adhesion molecules. E2 exerted distinct cell-type and function-specific modulation, the mechanisms underlying which are worthy of further detailed study.

Nintasen, Rungrat [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom) [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom); Multidisciplinary Cardiovascular Research Center (MCRC), University of Leeds, Leeds LS2 9JT (United Kingdom); Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University (Thailand); Riches, Kirsten; Mughal, Romana S. [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom) [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom); Multidisciplinary Cardiovascular Research Center (MCRC), University of Leeds, Leeds LS2 9JT (United Kingdom); Viriyavejakul, Parnpen; Chaisri, Urai; Maneerat, Yaowapa [Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University (Thailand)] [Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University (Thailand); Turner, Neil A. [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom) [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom); Multidisciplinary Cardiovascular Research Center (MCRC), University of Leeds, Leeds LS2 9JT (United Kingdom); Porter, Karen E., E-mail: medkep@leeds.ac.uk [Division of Cardiovascular Medicine, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom); Multidisciplinary Cardiovascular Research Center (MCRC), University of Leeds, Leeds LS2 9JT (United Kingdom)

2012-04-20

47

In vitro and immunological assessment of the estrogenic activity and concentrations of 17beta-estradiol, estrone, and ethinyl estradiol in treated effluent from 45 wastewater treatment plants in Victoria, Australia.  

PubMed

The project was conducted between May 2006 and September 2007, and involved the collection of effluent samples from 45 wastewater treatment plants (WWTPs). The 45 WWTPs included 16 lagoon-based plants and 29 with activated sludge-based processes. Permission was obtained from all the relevant water authorities to collect samples of final effluent at point of discharge to the environment, whether that was to a creek, a river, the ocean, or the land. Samples were collected on two occasions, namely, in August 2006 (winter) and late February-early March 2007 (summer), and subjected to a number of biological and chemical analyses, including toxicity tests, measurement of hormonal (estrogenic) activity using yeast-based bioassays, and measurement of specific hormonal concentrations using enzyme-linked immunosorbent assays (ELISAs). Almost all of the effluents examined showed estrogenic activity: in winter, no activity to 73 ng/l 17beta-estradiol equivalents (EEQ); and in summer, no activity to 20 ng/l EEQ. On the whole, the levels of estrogenic activity observed were comparable with the range recently reported in Australia and New Zealand using human estrogen receptor-based assays ("not detected" to approximately 10 ng/l EEQ). The low/no bioassay response was confirmed by the chemical assessment of estradiol, estrone, and ethinyl estradiol concentrations by ELISA, which returned concentrations of these compounds for the most part below 10 ng/l. PMID:20130850

Allinson, M; Shiraishi, F; Salzman, S A; Allinson, G

2010-04-01

48

FoxM1 influences embryo implantation and is regulated by 17 beta-estradiol and progesterone in mouse uteri and endometrium cells  

PubMed Central

To be a successful implantation, endometrial receptivity should be established. Forkhead box M1 (FoxM1) is described as a major oncogenic transcription factor in tumor initiation, promotion, and progression. FoxM1 regulates the expression of lots of targeted genes important to cell differentiation, proliferation and apoptosis; cell-cycle progression; and tumor angiogenesis, migration, invasion, and metastasis. According to these functions, we believe that FoxM1 should also play an essential role in embryo implantation. To test our hypothesis, we observed the expression and distribution of FoxM1 during the early pregnancy of mouse. Then, we used Immunohistochemistry to examine the expression of FoxM1 induced by E2 and/or P4 in the ovariectomized mouse uterus and human endometrium cells. This study further investigated whether FoxM1 was an important factor in the implantation. Our results showed that FoxM1 expressed in the mouse uterus during early pregnancy (Day 1 to 5). The expression of FoxM1 gradually increased along pregnancy process; FoxM1 expression could be increased by E2. On the contrary, FoxM1 expression could be decreased by P4 and E2 plus P4. We also detected the proliferation of human endometrium cells. We found that E2 might promote cells proliferation, while P4 and E2 plus P4 inhibited cells proliferation; Inhibiting FoxM1 could interfere the embryo implantation of mouse. Amplification or inhibiting of FoxM1 in JAR cells can increase or decrease the adhesion rate to Rl95-2 and HEC-1A cells separately. Our data indicate that FoxM1 might play an important role during the process of mouse embryo implantation. PMID:25400737

Xie, Yunpeng; Cui, Dan; Kong, Ying

2014-01-01

49

Reconnaissance of 17 beta-estradiol, 11-ketotestosterone, vitellogenin, and gonad histopathology in common carp of United States streams; potential for contaminant-induced endocrine disruption  

USGS Publications Warehouse

A reconnaissance of sex steroid hormones and other biomarkers in common carp was used to assess whether endocrine disruption may be occurring in fish in United States streams, to evaluate relations between endocrine disruption and contaminant levels, and to determine requirements for further studies. 17?-estradiol, 11-ketotestosterone, vitellogenin, and gonadal histopathology were measured in adult carp (usually 10--15 for each sex) at 25 sites (647 fish), representing a wide range of environmental settings typical of major regions of the nation. Fish were collected during August--December 1994, a period of gonadal maturation after spawning. Contaminants evaluated were organochlorine pesticides and polychlorinated biphenyls in tissue; phthalates, phenols, and polycyclic aromatic hydrocarbons in bed sediment; and dissolved pesticides in water. Mean site concentrations of steroid hormones spanned two orders of magnitude for both sexes. No significant regional differences in steroid hormones were detected for males, but females from the Northern and Southern Midcontinent were significantly different from other regions of the country in one or both hormones. Within all regions there were significant differences between sites in one or both hormones for both sexes. Most correlation coefficients between biomarkers and contaminants were negative. Contaminants that had significant (a=0.05) correlations with biomarkers were organochlorine pesticides, phenols, and dissolved pesticides. The strongest pattern common to both males and females was a negative correlation between the hormone ratio (E2/11-KT) and dissolved pesticides. The significant site-to-site differences in biomarkers, and the presence of significant correlations between biomarkers and contaminants, are evidence that fish in some streams may be experiencing endocrine disruption. Improved information is needed to evaluate whether endocrine disruption is actually occurring and if there are reproductive effects on individual or populations of carp or other species. Future studies should shift to more intensive study of fewer sites, including reference and contaminated sites, in order to address these additional questions.

Goodbred, Steven L.; Gilliom, Robert J.; Gross, Timothy S.; Denslow, Nancy P.; Bryant, Wade B.; Schoeb, Trenton R.

1997-01-01

50

Land-cover effects on the fate and transport of surface-applied antibiotics and 17-beta-estradiol on a sandy outwash plain, Anoka County, Minnesota, 2008–09  

USGS Publications Warehouse

A plot-scale field experiment on a sandy outwash plain in Anoka County in east-central Minnesota was used to investigate the fate and transport of two antibiotics, sulfamethazine (SMZ) and sulfamethoxazole (SMX), and a hormone, 17-beta-estradiol (17BE), in four land-cover types: bare soil, corn, hay, and prairie. The SMZ, SMX, and 17BE were applied to the surface of five plots of each land-cover type in May 2008 and again in April 2009. The cumulative application rate was 16.8 milligrams per square meter (mg/m2) for each antibiotic and 0.6 mg/m2 for 17BE. Concentrations of each chemical in plant-tissue, soil, soil-water, and groundwater samples were determined by using enzyme-linked immunosorbent assay (ELISA) kits. Soil-water and groundwater sampling events were scheduled to capture the transport of SMZ, SMX, and 17BE during two growing seasons. Soil and plant-tissue sampling events were scheduled to identify the fate of the parent chemicals of SMZ, SMX, and 17BE in these matrices after two chemical applications. Areal concentrations (mg/m2) of SMZ and SMX in soil tended to decrease in prairie plots in the 8 weeks after the second chemical application, from April 2009 to June 2009, but not in other land-cover types. During these same 8 weeks, prairie plots produced more aboveground biomass and had extracted more water from the upper 125 centimeters of the soil profile compared to all other land-cover types. Areal concentrations of SMZ and SMX in prairie plant tissue did not explain the temporal changes in areal concentrations of these chemicals in soil. The areal concentrations of SMZ and SMX in the aboveground plant tissues in June 2009 and August 2009 were much lower, generally two to three orders of magnitude, than the areal concentrations of these chemicals in soil. Pooling all treatment plot data, the median areal concentration of SMZ and SMX in plant tissues was 0.01 and 0.10 percent of the applied chemical mass compared to 22 and 12 percent in soil, respectively. Furthermore, areal concentrations of SMZ and SMX in plant-tissue samples were variable, and did not differ significantly between control and treatment plots within each land-cover type. SMZ was detected in 23 percent of soil-water samples and in 16 percent of groundwater samples collected between October 2008 and October 2009 in treatment plots, indicating that surface-applied SMZ leached below the rooting zone and reached groundwater. SMX was detected in only 1 percent of soil-water and groundwater samples during this same time period. In contrast to the antibiotics, 17BE was not reliably detected in soil samples. Additionally, ELISA-determined 17BE concentrations in plant-tissue, soil-water, and groundwater samples indicated the presence of chemicals that were not applied as part of this experiment [17BE from an external source or other chemical(s) that interfered with the 17BE ELISA kits].

Trost, Jared J.; Kiesling, Richard L.; Erickson, Melinda L.; Rose, Peter J.; Elliott, Sarah M.

2013-01-01

51

Alterations in osteoclast morphology following long-term 17beta-estradiol administration in the mouse  

PubMed Central

Background Although the role of the osteoclast in bone resorption is becoming better understood, much remains to be learned about osteoclastogenesis and the exact mechanism of action of anti-resorbing agents such as 17?-estradiol. This study investigated bone and morphologic osteoclast alterations following long-term estrogen administration to the B6D2F1 mouse. B6D2F1 mice aged 4-5 weeks were exposed to high levels of estrogen via implanted silastic tubing for at least 12 weeks; controls received empty tubing. Femurs of control and treated mice were assessed with radiology, quantitative histomorphometry and transmission electron microscopy. Results After 8 weeks of treatment, there was radiologic evidence of severe osteosclerosis and 86% of femoral marrow space was replaced with bone. After 12 weeks histologic studies of treated animals revealed that osteoclasts were positive for tartrate-resistant acid phosphatase but showed markedly abnormal ultrastructure which prevented successful bone resorption. Conclusions Findings extend our understanding of osteoclast structure and function in the mouse exposed in vivo to high doses of estrogen. Ultrastructural examination showed that osteoclasts from estrogen-treated mice were unable to seal against the bone surface and were unable to form ruffled borders. PMID:11231877

Gruber, Helen E; Puzanov, Igor J; Bennett, Michael; Kumar, Vinay; Gordon, Brian

2001-01-01

52

The chemical behavior of estrone and 17beta-estradiol in the environment  

E-print Network

to thank David Liere and all the other livestock producers that have helped me in my pursuits. vii TABLE OF CONTENTS Page 1. INTRODUCTION TO ESTROGENS OF AGRICULTURAL ORIGIN: A LITERATURE REVIEW OF EFFECTS, SOURCES.....…………………………………………………… 38 3.3. Results and Discussion.…………………………………………………… 39 viii Page 3.3.1. Equilibrium Determination……...…………………………………… 39 3.3.2. Adsorption…….....…………………………………………………… 40 3.3.3. Desorption…….....…………………………………………………… 49...

Ullman, Jeffrey Layton

2007-09-17

53

Lipocalin 2: a "sexy" adipokine that regulates 17Beta-estradiol and obesity  

Technology Transfer Automated Retrieval System (TEKTRAN)

In this article we review the findings of Guo et. al. (Endocrinology, 153: 1183-1193) that the protein, Lipocalin 2 is more highly expressed in subcutaneous adipose tissue than in gondal tissue of female mice. Of particular interest is that the paper by Guo et. al. observed that ablation of the Lip...

54

Inhibition of 17 beta-estradiol and progesterone activity in human breast and endometrial cancer cells by carbamate insecticides  

Microsoft Academic Search

Using a combination of in vitro assays we have examined the capacities of contemporary-exposure chemicals to modulate human estrogen and human progesterone receptor (hER and hPR) activity in human breast and endometrial cancer cells. The carbamate insecticides aldicarb, Baygon (propoxur), bendiocarb, carbaryl, methomyl, and oxamyl were used in this study. The carbamates alone weakly activated estrogen- or progesterone-responsive reporter genes

Diane M. Klotz; Steven F. Arnold; John A. McLachlan

1997-01-01

55

Effects of 17Beta-estradiol on cognitive performance of ovariectomized female rats exposed to 56Fe particles  

Technology Transfer Automated Retrieval System (TEKTRAN)

On exploratory class missions to other planets astronauts will be exposed to types and doses of radiation (HZE particles) that are not experienced in low earth orbit. While it is likely that the crew will consist of both male and female astronauts, there has been little research on the effects of ...

56

A metabolomics study of the inhibitory effect of 17-beta-estradiol on osteoclast proliferation and differentiation.  

PubMed

Estradiol is a major drug used clinically to alleviate osteoporosis, partly through inhibition of the activity of osteoclasts, which play a crucial role in bone resorption. So far, little is known about the effects of estradiol on osteoclast metabolism. In this study, ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC/MS)-based metabolomics strategy was used to investigate the metabolite response to 17?-estradiol in mouse osteoclast RAW264.7, a commonly used cell model for studying osteoporosis. Our results showed that the application of estradiol altered the levels of 27 intracellular metabolites, including lysophosphatidylcholines (LysoPCs), other lipids and amino acid derivants. The changes of all the 27 metabolites were observed in the study of estradiol induced osteoclast proliferation inhibition (1 ?M estradiol applied), while the changes of only 18 metabolites were observed in the study of differentiation inhibition (0.1 ?M estradiol applied). Further pathway impact analysis determined glycerophospholipid metabolism as the main potential target pathway of estradiol, which was further confirmed by LCAT (phosphatidylcholine-sterol acyltransferase) activity changes and lipid peroxidative product (MDA, methane dicarboxylic aldehyde) changes caused by estradiol. Additionally, we found that estradiol significantly decreased intracellular oxidative stress during cell proliferation but not during cell differentiation. Our study suggested that estradiol generated a highly condition-dependent influence on osteoclast metabolism. PMID:25474166

Liu, Xiaoyan; Liu, Yanqiu; Cheng, Mengchun; Zhang, Xiaozhe; Xiao, Hongbin

2015-02-20

57

The effect of 17 beta-estradiol on cholesterol in human macrophages is influenced by the lipoprotein milieu  

Technology Transfer Automated Retrieval System (TEKTRAN)

Estrogen and testosterone are thought to modulate coronary heart disease (CHD) risk. To examine how these hormones affect human macrophage cholesterol transport, a key factor in atherogenesis, we obtained monocytes from healthy male and postmenopausal female donors (age 50-70 y). Cells were allowe...

58

Parenteral 17beta-estradiol decreases fasting blood glucose levels in non-obese mice with short-term ovariectomy  

Microsoft Academic Search

AimsLong-term ovariectomy-induced metabolic changes such as insulin resistance and glucose intolerance might be caused directly by estrogen deficiency and may occur partly as secondary effects of obesity arising due to the orexigenic effects of estrogen deficiency. Long-term estrogen treatment prevented those by exerting anorexigenic and metabolic actions in ovariectomized mice. However, the effect of short-term estrogen treatment on glucose metabolism

Ju-Young Kim; Kyung-Jin Jo; Ok-Soon Kim; Byung-Joon Kim; Dong-Wook Kang; Ki-Ho Lee; Haing-Woon Baik; Min Soo Han; Seong-Kyu Lee

2010-01-01

59

PROMOTION BY 17BETA-ESTRADIOL AND BETA-HEXACHLOROCYCLOHEXANE OF HEPATOCELLULAR TUMORS IN MEDAKA, ORYZIAS LATIPES. (R825298)  

EPA Science Inventory

Abstract A feature common to many laboratory and field studies with various fish species is a higher prevalence of hepatocellular neoplasia in females than in males. During female sexual maturation, endogenous estrogens stimulate substantial increases in synthetic acti...

60

Estradiol-Induced Object Memory Consolidation in Middle-Aged Female Mice Requires Dorsal Hippocampal Extracellular Signal-Regulated Kinase and Phosphatidylinositol 3-Kinase Activation  

E-print Network

We previously demonstrated that dorsal hippocampal extracellular signal-regulated kinase (ERK) activation is necessary for 17?[beta]-estradiol (E2[E subscript 2]) to enhance novel object recognition in young ovariectomized ...

Lewis, Michael C.

61

Modulation of vitellogenin synthesis through estrogen receptor beta-1 in goldfish (Carassius auratus) juveniles exposed to 17-{beta} estradiol and nonylphenol  

SciTech Connect

Many synthetic chemicals, termed xenoestrogens, have been shown to interact as agonists with the estrogen receptor (ER) to elicit biological responses similar to those of natural hormones. To date, the regulation of vitellogenesis in oviparous vertebrates has been widely used for evaluation of estrogenic effects. Therefore, Carassius auratus juveniles were chosen as a fish model for studying the effects of estradiol-17{beta} and different concentrations (10{sup -6} and 10{sup -7} M) of 4-nonylphenol (4-NP) on the expression of liver ER{beta}-1 subtype; plasma vitellogenin and sex steroids (androgens and estradiol-17{beta}) were also evaluated together with the bioaccumulation process, through mass-spectrometry. C. auratus is a species widespread in the aquatic environment and, on the toxicological point of view, can be considered a good 'sentinel' species. Juveniles of goldfish were maintained in tanks with only tap water or water with different concentrations (10{sup -6} and 10{sup -7} M) of 4-nonylphenol (4-NP), or 10{sup -7} M of estradiol-17{beta}. After 3 weeks of treatment, animals were anesthetized within 5 min after capture, and blood was immediately collected into heparinized syringes by cardiac puncture and stored at -70 deg. C; the gonads were fixed, then frozen and stored at -70 deg. C; the whole fish, liver, and muscle tissues were harvested and immediately stored at -70 deg. C for molecular biology experiments and bioaccumulation measurements. The estrogenic effects of 4-NP were evidenced by the presence of plasma vitellogenin in juveniles exposed both to estradiol-17{beta} and the two doses of 4-NP; moreover, exposure to 4-NP also increased aromatization of androgens, as suggested by decreasing androgens and increasing estradiol-17{beta} plasma levels. The changes of these parameters were in agreement with the increasing transcriptional rate of ER{beta}-1 mRNA in the liver, demonstrating that both estradiol-17{beta} and 4-NP modulate the vitellogenin rate through interaction with the ER{beta}-1 subtype. The present study also suggests that 4-NP at the concentration of 10{sup -6} M bioaccumulates in the liver.

Soverchia, L. [Dipartimento di Medicina Sperimentale e Sanita Pubblica, Universita degli Studi di Camerino, via Scalzino 3, 62032 Camerino (Monaco) (Italy); Ruggeri, B. [Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Universita degli Studi di Camerino, via Camerini 2, 62032 Camerino (Monaco) (Italy); Palermo, F. [Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Universita degli Studi di Camerino, via Camerini 2, 62032 Camerino (Monaco) (Italy); Mosconi, G. [Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Universita degli Studi di Camerino, via Camerini 2, 62032 Camerino (Monaco) (Italy); Cardinaletti, G. [Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Universita degli Studi di Camerino, via Camerini 2, 62032 Camerino (Monaco) (Italy); Scortichini, G. [Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale', Campo Boario, 64100 Teramo (Italy); Gatti, G. [Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale', Campo Boario, 64100 Teramo (Italy); Polzonetti-Magni, A.M. [Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Universita degli Studi di Camerino, via Camerini 2, 62032 Camerino (Monaco) (Italy)]. E-mail: alberta.polzonetti@unicam.it

2005-12-15

62

17beta Estradiol Inhibits Apoptosis in MCF7 Cells, Inducing bcl-2 Expression via Two Estrogen-Responsive Elements Present in the Coding Sequence  

Microsoft Academic Search

We have found that 17b-estradiol induces bcl-2 transcription in human breast cancer MCF-7 cells. To identify cis-acting elements involved in this regulation, we have analyzed hormone responsiveness of transiently transfected reporter constructs containing the bcl-2 major promoter (P1). Hormone inducibility was observed only when either of two sequences, located within the bcl-2 coding region and showing one and two mutations

BRUNO PERILLO; ANNARITA SASSO; CIRO ABBONDANZA; GIUSEPPE PALUMBO

2000-01-01

63

DETERMINING THE SENSITIVE DEVELOPMENTAL STAGES OF INTERSEX INDUCTION IN MEDAKA (ORYZIAS LATIPES) EXPOSED TO 17 BETA-ESTRADIOL OR TESTOSTERONE. (R825298)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

64

A Computational Model of the Hypothalamic-pituitary-gonadal Axis in Male Fathead Minnows Exposed to 17 | *alpha* | -ethinylestradiol and 17 | *beta* | -estradiol  

EPA Science Inventory

Estrogenic chemicals in the aquatic environment have been shown to cause a variety of reproductive anomalies in fish including full sex reversal, intersex, and altered population sex ratios. Two estrogens found in the aquatic environment, 17-ethinylestradiol and 17â-estradiol, h...

65

SPE-LC/ESI/MS: a simple and reproducible method for detection and quantification of 17beta-estradiol in aqueous samples  

Technology Transfer Automated Retrieval System (TEKTRAN)

Steroid estrogens contained in wastewater discharge from sewage treatment plants and agricultural run-off can alter endocrine function in exposed wildlife at part per trillion (ng/L) levels. Detection and quantification of estrogens in the environment at these levels pose numerous analytical challen...

66

Mammary gland morphology and gene expression differ in female rats treated with 17 beta-estradiol or fed soy protein isolate  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soy foods have been suggested to have both positive health benefits and potentially adverse effects as a result of their content of phytoestrogens. However, studies on the estrogenicity of soy foods are lacking. Here we directly compared the effects of soy protein isolate (SPI), the protein in soy i...

67

DNA ARRAYS TO MONITOR GENE EXPRESSION IN RAT BLOOD AND UTERUS FOLLOWING 17BETA-ESTRADIOL EXPOSURE: BIOMONITORING ENVIRONMENTAL EFFECTS USING SURROGATE TISSUES  

EPA Science Inventory

We propose that gene expression changes in accessible tissues such as blood often reflect those in inaccessible tissues, thus offering a convenient biomonitoring method to provide insight into the effects of environmental toxicants on such tissues. In this pilot study, gene expre...

68

Pathogenic infection confounds induction of the estrogenic biomarker vitellogenin in rainbow trout  

Technology Transfer Automated Retrieval System (TEKTRAN)

To examine the behavior of the estrogenic biomarker vitellogenin (VTG) under the combined impact of estrogens and pathogens, parasite-infected or noninfected rainbow trout were exposed to two doses of 17 beta-estradiol (E2). Infected and E2-exposed fish showed significantly lower hepatic VTG mRNA le...

69

Sorption, fate, and transport of endogenous steroid hormones in soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

The natural hormones 17 beta-estradiol (E2) and testosterone (T) are present in animal manures that are applied to agricultural land as fertilizer and, potentially, may act as endocrine disruptors. Laboratory incubation, batch, and column experiments have been conducted on a series of soils and wer...

70

The E(2) particle  

SciTech Connect

Recently it has been advocated [A. G. Cohen and S. L. Glashow, Phys. Rev. Lett. 97, 021601 (2006)] that for describing nature within the minimal symmetry requirement, certain subgroups of the Lorentz group may play a fundamental role. One such group is E(2) which induces a Lie algebraic noncommutative spacetime [M. M. Sheikh-Jabbari and A. Tureanu, Phys. Rev. Lett. 101, 261601 (2008); arXiv:0811.3670] where translation invariance is not fully maintained. We have constructed a consistent structure of noncommutative phase space for this system, and furthermore we have studied an appropriate point particle action on it. Interestingly, the Einstein dispersion relation p{sup 2}=m{sup 2} remains intact. The model is constructed by exploiting a dual canonical phase space following the scheme developed by us earlier [S. Ghosh and P. Pal, Phys. Rev. D 75, 105021 (2007)].

Ghosh, Subir; Pal, Probir [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 Barrackpore Trunk Road, Kolkata 700108 (India); Physics Department, Uluberia College, Uluberia, Howrah 711315 (India) and S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata-700098 (India)

2009-12-15

71

26 CFR 1.367(e)-2 - Distributions described in section 367(e)(2).  

Code of Federal Regulations, 2010 CFR

...Revenue 4 2010-04-01 2010-04-01 false Distributions described in section 367(e)(2). 1.367(e)-2 Section 1.367(e)-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED)...

2010-04-01

72

DNA-damage response control of E2F7 and E2F8  

Microsoft Academic Search

Here, we report that the two recently identified E2F subunits, E2F7 and E2F8, are induced in cells treated with DNA-damaging agents where they have an important role in dictating the outcome of the DNA-damage response. The DNA-damage-dependent induction coincides with the binding of E2F7 and E2F8 to the promoters of certain E2F-responsive genes, most notably that of the E2F1 gene,

L Panagiotis Zalmas; Xiujie Zhao; Anne L Graham; Rebecca Fisher; Carmel Reilly; Amanda S Coutts; Nicholas B La Thangue

2008-01-01

73

E2F-8: an E2F family member with a similar organization of DNA-binding domains to E2F-7  

Microsoft Academic Search

E2F is a family of transcription factors implicated in cell cycle control. To understand the role of E2F in controlling cell cycle progression, it is necessary to clarify the breadth of the E2F family. To date, seven E2F subunits have been identified. We report here the characterization of a new E2F subunit, E2F-8, which resembles the organization of E2F-7 in

Nicola Logan; Anne Graham; Xuijie Zhao; Rebecca Fisher; Baidehi Maiti; Gustavo Leone; Nicholas B La Thangue

2005-01-01

74

26 CFR 1.367(e)-2 - Distributions described in section 367(e)(2).  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Distributions described in section 367(e)(2...Corporation § 1.367(e)-2 Distributions described in section 367(e)(2...recognition by a corporation on its distribution of property to a foreign...

2012-04-01

75

26 CFR 1.367(e)-2 - Distributions described in section 367(e)(2).  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Distributions described in section 367(e)(2...Corporation § 1.367(e)-2 Distributions described in section 367(e)(2...recognition by a corporation on its distribution of property to a foreign...

2013-04-01

76

26 CFR 1.367(e)-2 - Distributions described in section 367(e)(2).  

...2014-04-01 2014-04-01 false Distributions described in section 367(e)(2...Corporation § 1.367(e)-2 Distributions described in section 367(e)(2...recognition by a corporation on its distribution of property to a foreign...

2014-04-01

77

Different modulation of steroidogenesis and prostaglandin production in frog ovary in vitro by ACE and ANG II.  

PubMed

Our aim was to study the role of angiotensin-converting enzyme (ACE) and angiotensin II (ANG II) on ovarian steroidogenesis and prostaglandin production of amphibian. Hormonal effects of ACE, ACE inhibitors, synthetic bullfrog angiotensin I (ANG I), and [Val5]ANG II were compared on frog ovaries of postreproductive and prereproductive periods. Very high ACE activity was found in ovary of water frog (Rana esculenta) compared with other frog tissues, and this activity was inhibited by the typical ACE inhibitors, captopril and lisinopril. Frog ovary tissue in postreproductive and prereproductive periods was incubated in vitro in the presence of ACE (2.5 mU/ml), captopril (0.1 mM), lisinopril (0.1 mM), [Val5]ANG II (1 microM), and synthetic bullfrog ANG I (1 microM). Production of 17 beta-estradiol, progesterone, androgens, and prostaglandins E2 and F2 alpha was determined. The data showed a modulation of 17 beta-estradiol, progesterone, and prostaglandin E2 production by ovary ACE; on the other hand, [Val5]ANG II modulated the production of progesterone and prostaglandin F2 alpha, whereas androgen production was not influenced. The present in vitro studies suggest the existence of two pathways independently regulated by ACE and ANG II modulating ovarian steroidogenesis and prostaglandin production. PMID:9435665

Bramucci, M; Miano, A; Gobbetti, A; Zerani, M; Quassinti, L; Maccari, E; Murri, O; Amici, D

1997-12-01

78

Regulation of mitochondrial respiratory chain structure and function by estrogens/estrogen receptors and potential physiological/pathophysiological implications.  

PubMed

It is well known that the biological and carcinogenic effects of 17beta-estradiol (E2) are mediated via nuclear estrogen receptors (ERs) by regulating nuclear gene expression. Several rapid, non-nuclear genomic effects of E2 are mediated via plasma membrane-bound ERs. In addition, there is accumulating evidence suggesting that mitochondria are also important targets for the action of estrogens and ERs. This review summarized the studies on the effects of estrogens via ERs on mitochondrial structure and function. The potential physiological and pathophysiological implications of deficiency and/or overabundance of these E2/ER-mediated mitochondrial effects in stimulation of cell proliferation, inhibition of apoptosis, E2-mediated cardiovascular and neuroprotective effects in target cells are also discussed. PMID:16169101

Chen, Jin-Qiang; Yager, James D; Russo, Jose

2005-10-30

79

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

E2I EPRI Assessment Offshore Wave Energy Conversion Devices Report: E2I EPRI WP ­ 004 ­ US ­ Rev 1 #12;E2I EPRI Assessment - Offshore Wave Energy Conversion Devices Table of Contents Introduction Assessment - Offshore Wave Energy Conversion Devices Introduction E2I EPRI is leading a U.S. nationwide

80

Mouse Development with a Single E2F Activator  

PubMed Central

The E2F family is conserved from C. elegans to mammals with some family members having transcription activation functions and others having repressor functions1, 2. Whereas C. elegans3 and Drosophila melanogaster4, 5 have a single E2F activator and repressor proteins, mammals evolved to have at least three activator and five repressor proteins1, 2, 6. Why such genetic complexity evolved in mammals is not known. To begin to evaluate this genetic complexity, we targeted the inactivation of the entire subset of activators, E2f1, E2f2, E2f3a and E2f3b, singly or in combination in mice. We demonstrate that E2f3a is sufficient to support mouse embryonic and postnatal development. Remarkably, expression of E2f3b or E2f1 from the E2f3a locus (E2f3a3bki; E2f3a1ki) suppressed all the postnatal phenotypes associated with the inactivation of E2f3a. We conclude that there is significant functional redundancy among activators and that the specific requirement for E2f3a during postnatal development is dictated by regulatory sequences governing its selective spatiotemporal expression and not by its intrinsic protein functions. These findings provide a molecular basis for the observed specificity among E2F activators during development. PMID:18594513

Tsai, Shih-Yin; Opavsky, Rene; Sharma, Nidhi; Wu, Lizhao; Naidu, Shan; Nolan, Eric; Feria-Arias, Enrique; Timmers, Cynthia; Opavska, Jana; de Bruin, Alain; Chong, Jean-Leon; Trikha, Prashant; Fernandez, Soledad A.; Stromberg, Paul; Rosol, Thomas J.; Leone, Gustavo

2010-01-01

81

Estradiol prevents olfactory dysfunction induced by A-? 25–35 injection in hippocampus  

PubMed Central

Background Some neurodegenerative diseases, such as Alzheimer and Parkinson, present an olfactory impairment in early stages, and sometimes even before the clinical symptoms begin. In this study, we assess the role of CA1 hippocampus (structure highly affected in Alzheimer disease) subfield in the rats’ olfactory behavior, and the neuroprotective effect of 17 beta estradiol (E2) against the oxidative stress produced by the injection of amyloid beta 25–35. Results 162 Wistar rats were ovariectomized and two weeks after injected with 2 ?l of amyloid beta 25–35 (A-?25–35) in CA1 subfield. Olfactory behavior was evaluated with a social recognition test, odor discrimination, and search tests. Oxidative stress was evaluated with FOX assay and Western Blot against 4-HNE, Fluoro Jade staining was made to quantify degenerated neurons; all these evaluations were performed 24 h, 8 or 15 days after A-?25–35 injection. Three additional groups treated with 17 beta estradiol (E2) were also evaluated. The injection of A-?25–35 produced an olfactory impairment 24 h and 8 days after, whereas a partial recovery of the olfactory behavior was observed at 15 days. A complete prevention of the olfactory impairment was observed with the administration of E2 two weeks before the amyloid injection (A-?25–35 24 h?+?E2) and one or two weeks after (groups 8 A-? +E2 and 15 A-? +E2 days, respectively); a decrease of the oxidative stress and neurodegeneration were also observed. Conclusions Our finding shows that CA1 hippocampus subfield plays an important role in the olfactory behavior of the rat. The oxidative stress generated by the administration of A-?25–35 is enough to produce an olfactory impairment. This can be prevented with the administration of E2 before and after amyloid injection. This suggests a possible therapeutic use of estradiol in Alzheimer’s disease. PMID:24059981

2013-01-01

82

Wogonin inhibits inducible prostaglandin E 2 production in macrophages  

Microsoft Academic Search

Effects of 5,7-dihydroxy-8-methoxyflavone (wogonin) on cyclooxygenase-2 (COX-2)-mediated prostaglandin E2 production in macrophages were investigated. Stimulation with lipopolysaccharide (LPS; 1 ?g\\/ml) greatly increased prostaglandin E2 production in RAW 264.7 murine macrophages. The stimulated prostaglandin E2 production was abolished in the presence of indomethacin (1 ?M) or cycloheximide (2 ?M), suggesting that the increased production of prostaglandin E2 by LPS reflects the

Ichiro Wakabayashi; Kenichi Yasui

2000-01-01

83

Developing a Biosensor for Estrogens in Water Samples: Study ofthe Real-time Response of Live Cells of the Estrogen-sensitive YeastStrain RMY/ER-ERE using Fluorescence Microscopy  

SciTech Connect

Using a fluorescein di-{beta}-D-galactopyranoside (FDG) substrate we show that in live cells of an estrogen-sensitive yeast strain RMY/ER-ERE with human estrogen receptor (ER{alpha}) gene and the lacZ gene which encodes {beta}-galactosidase, the uptake of 17 {beta}-estradiol (E2) and the subsequent production of {beta}-galactosidase enzyme occur quite rapidly, with maximal enzyme-catalyzed product formation evident after about 30 minutes of exposure to E2. This finding which agrees with the well-known rates of enzyme-catalyzed reactions could have implications for shortening the duration of environmental sample screening and monitoring regimes using yeast-based estrogen assays, and the development of biosensors for environmental estrogens to complement quantification methods.

Wozei, E.; Hermanowicz, S.W.; Holman, H-Y.N.

2005-07-13

84

Epidemiology of Endometrial Cancer Consortium (E2C2)  

Cancer.gov

The Epidemiology of Endometrial Cancer Consortium (E2C2) is an NCI-supported consortium dedicated to studying the etiology of this common cancer through collaboration among investigators. The overall objective of E2C2 is to build on resources from existing studies by combining data across studies in order to advance our understanding of the etiology of this disease.

85

Cloning and characterization of E2F6, a novel member of the E2F transcription factor family  

E-print Network

The E2F family of proteins plays a critical role in the regulation of genes that are essential for progression through the cell-cycle. Based upon sequence homology and functional properties, the E2F group can be subdivided ...

Trimarchi, Jeffrey Michael, 1970-

2002-01-01

86

E2F and microRNA regulation of angiogenesis  

PubMed Central

E2F family of transcription factors are best known for regulating genes involved in cell cycle control, cell proliferation, tumorigenesis, and apoptosis. Recent evidences have revealed their critical involvement in modulating cellular response to hypoxia and ischemia in a variety of physiological and pathological processes. Of particular interest are findings that E2Fs act as both regulators and targets of microRNAs that govern hypoxic/ischemic angiogenesis. This review focuses on the crosstalk between E2Fs and microRNAs that have been shown to participate in the regulation of angiogenesis, hypoxia response and ischemic disease. PMID:22200034

Biyashev, Dauren; Qin, Gangjian

2011-01-01

87

E2F6 in axial skeletal development and gliosis  

E-print Network

E2F transcription factors were originally identified as regulators of cell cycle and cellular proliferation. In vivo mouse models have uncovered novel roles for these proteins in different developmental processes. This ...

Friesenhahn, Laurie Beth

2008-01-01

88

Loss of dE2F compromises mitochondrial function  

PubMed Central

SUMMARY E2F/DP transcription factors regulate cell proliferation and apoptosis. Here, we investigated the mechanism of the resistance of Drosophilad DP mutants to irradiation-induced apoptosis. Contrary to the prevailing view, this is not due to an inability to induce the apoptotic transcriptional program, since we show that this program is induced, but rather due to a mitochondrial dysfunction of dDP mutants. We attribute this defect to E2F/DP-dependent control of expression of mitochondria associated genes. Genetic attenuation of several of these E2F/DP targets mimics the dDP mutant mitochondrial phenotype and protects from irradiation-induced apoptosis. Significantly, the role of E2F/DP in the regulation of mitochondrial function is conserved between flies and humans. Thus, our results uncovered a role of E2F/DP in the regulation of mitochondrial function and demonstrate that this aspect of E2F regulation is critical for the normal induction of apoptosis in response to irradiation. PMID:24286825

Ambrus, Aaron M; Islam, Abul BMMK; Holmes, Katherine B.; Moon, Nam Sung; Lopez-Bigas, Nuria; Benevolenskaya, Elizaveta V; Frolov, Maxim V

2013-01-01

89

Loss of HPV16 E2 Protein Expression Without Disruption of the E2 ORF Correlates with Carcinogenic Progression  

PubMed Central

Integration of the viral DNA in the cellular genome has been suggested to be critical in carcinogenic progression of HPV-associated cervical neoplasia. This event can be accompanied by disruption of the open reading frame (ORF) encoding the E2 repressor, thus leading to transcriptional up-regulation of the E6 and E7 viral oncogenes. At this stage, it is unclear whether disruption of the E2 ORF is mandatory for carcinogenic progression. We measured E2 RNA and protein expression in clinical samples of various grades of HPV16-associated cervical neoplasia and compared it with the status of the viral genome. RNA extracted from paraffin embedded tissues was hybridized to specific probes and quantified by the NanoString technology. Protein expression was appreciated by immunohistochemistry and the status of viral DNA was determined by in situ hybridization, all performed on serial sections of the same samples. E2 protein was found highly expressed in CIN1, CIN2 lesions where the HPV DNA was highly replicative, while it was decreased in more advanced grade lesions where replication is decreased or lost (CIN3 and SCC). In contrast, E2 transcripts could be elevated even in conditions of no or low expression of the protein, as found in the Caski cell line. Our data demonstrate that integration of the viral DNA in the cellular genome does not always lead to disruption of the E2 ORF and drastic reduction of E2 transcripts, while in contrast, expression of the E2 protein is always drastically reduced. PMID:23341852

Xue, Yuezhen; Lim, Diana; Zhi, Liang; He, Pingping; Abastado, Jean-Pierre; Thierry, Françoise

2012-01-01

90

B (e 2 ;21+?01+) value in 90Kr  

NASA Astrophysics Data System (ADS)

A smooth onset of collectivity in 88 ,92 ,94 ,96Kr has been determined from reported B (E 2 ;21+?01+) and E (21+) values. This is in contrast to the sudden onset in even-even Zr, Mo, and Sr isotopes. Our objective was to complete the systematics by determining the B (E 2 ;21+?01+) value in 90Kr, which was produced by cold-neutron-induced fission of 235U . The lifetime of the 21+ state in 90Kr was measured via the electronic ? -? timing technique using the EXILL and FATIMA spectrometers. Based on the measured mean lifetime of ? = 15(10) ps, the B (E 2 ;21+?01+) value of 13 -5+26 W.u. in 90Kr is determined for the first time and the smooth onset of deformation in the even-even Kr isotopes beyond neutron number N =50 is confirmed.

Régis, J.-M.; Jolie, J.; Saed-Samii, N.; Warr, N.; Pfeiffer, M.; Blanc, A.; Jentschel, M.; Köster, U.; Mutti, P.; Soldner, T.; Simpson, G. S.; Drouet, F.; Vancraeyenest, A.; de France, G.; Clément, E.; Stezowski, O.; Ur, C. A.; Urban, W.; Regan, P. H.; Podolyák, Zs.; Larijani, C.; Townsley, C.; Carroll, R.; Wilson, E.; Fraile, L. M.; Mach, H.; Paziy, V.; Olaizola, B.; Vedia, V.; Bruce, A. M.; Roberts, O. J.; Smith, J. F.; Kröll, T.; Hartig, A.-L.; Ignatov, A.; Ilieva, S.; Thürauf, M.; Lalkovski, S.; Ivanova, D.; Kisyov, S.; Korten, W.; Salsac, M.-D.; Zieli?ska, M.; M?rginean, N.; Ghit?, D. G.; Lic?, R.; Petrache, C. M.; Astier, A.; Leguillon, R.

2014-12-01

91

Estradiol in vivo regulation of brain mitochondrial proteome.  

PubMed

We used a combined proteomic and functional biochemical approach to determine the overall impact of 17beta-estradiol (E2) on mitochondrial protein expression and function. To elucidate mitochondrial pathways activated by E2 in brain, two-dimensional (2D) gel electrophoresis was conducted to screen the mitoproteome. Ovariectomized adult female rats were treated with a single injection of E2. After 24 h of E2 exposure, mitochondria were purified from brain and 2D analysis and liquid chromatography-tandem mass spectrometry protein identification were conducted. Results of proteomic analyses indicated that of the 499 protein spots detected by image analysis, a total of 66 protein spots had a twofold or greater change in expression. Of these, 28 proteins were increased in expression after E2 treatment whereas 38 proteins were decreased in expression relative to control. E2 regulated key metabolic enzymes including pyruvate dehydrogenase, aconitase, and ATP-synthase. To confirm that E2-inducible changes in protein expression translated into functional consequences, we determined the impact of E2 on the enzymatic activity of the mitochondrial electron transport chain. In vivo, E2 treatment enhanced brain mitochondrial efficiency as evidenced by increased respiratory control ratio, elevated cytochrome-c oxidase activity and expression while simultaneously reducing free radical generation in brain. Results of these analyses provide insights into E2 mechanisms of regulating brain mitochondria, which have the potential for sustaining neurological health and prevention of neurodegenerative diseases associated with mitochondrial dysfunction such as Alzheimer's disease. PMID:18094246

Nilsen, Jon; Irwin, Ronald W; Gallaher, Timothy K; Brinton, Roberta Diaz

2007-12-19

92

Estrogen-mediated suppression of cytochrome P4501A (CYP1A) expression in rainbow trout hepatocytes: role of estrogen receptor.  

PubMed

Hepatic CYP1A expression in fish can be modulated by the female sex hormone, 17beta-estradiol (E2), however neither the mechanism of E2 suppression of CYP1A nor the capacity for hormonal regulation to overcome CYP1A induction by xenobiotics are known. The present study investigates for the first time in fish if the estrogen receptor (ER) is involved in the suppressive action of E2 on CYP1A gene expression. The study further examines, if the E2 effect is able to overcome xenobiotic induction of CYP1A. As experimental model, in vitro cultures of rainbow trout, Oncorhynchus mykiss, hepatocytes were used. The effect of E2 on CYP1A was assessed by measuring the CYP1A-associated 7-ethoxyresorufin-O-deethylase (EROD) enzyme activity, and CYP1A mRNA contents. E2 at non-cytotoxic concentrations caused a significant time- and concentration-dependent decline of basal but not of induced hepatic EROD activities. The inhibitory action of E2 on basal CYP1A was also evident at the mRNA level. The presence of the ER antagonist tamoxifen abolished the inhibitory action of E2 on CYP1A expression. The results from these in vitro experiments provide evidence (a) that the ER is involved in the suppressive action of E2 on CYP1A, and (b) that E2 inhibitory action does not overcome xenobiotic induction of CYP1A. PMID:11714484

Navas, J M; Segner, H

2001-12-21

93

Cervical ripening with intravaginal prostaglandin E2 gel  

Microsoft Academic Search

We describe a technique of administering prostaglandin E2 (PGE2) in a viscous cellulose gel into the vagina to ripen the unfavourable cervix in patients requiring induction of labour. A total of 168 primigravidae were studied, of whom 102 received 2 mg PGE2 in 2% gel and 66 received 5 mg PGE2 in 4% gel. In the latter group, the state

I Z MacKenzie; M P Embrey

1977-01-01

94

ENVIRONMENTAL EFFECTS OF DREDGING AND DISPOSAL (E2-D2)  

EPA Science Inventory

US Army Corps of Engineers public web site for the "Environmental Effects of Dredging and Disposal" ("E2-D2") searchable database of published reports and studies about environmental impacts associated with dredging and disposal operations. Many of the reports and studies are ava...

95

E-2C Loads Calibration in DFRC Flight Loads Lab  

NASA Technical Reports Server (NTRS)

Objectives: a) Safely and efficiently perform structural load tests on NAVAIR E-2C aircraft to calibrate strain gage instrumentation installed by NAVAIR; b) Collect load test data and derive loads equations for use in NAVAIR flight tests; and c) Assist flight test team with use of loads equations measurements at PAX River.

Schuster, Lawrence S.

2008-01-01

96

Low-energy behavior of E 2 strength functions  

NASA Astrophysics Data System (ADS)

Electric quadrupole strength functions have been deduced from averages of a large number of E 2 transition strengths calculated within the shell model for the nuclides 94Mo and 95Mo. These strength functions are at variance with phenomenological approximations as provided by the Reference Input Parameter Library RIPL-3 for calculations of reaction rates on the basis of the statistical model.

Schwengner, R.

2014-12-01

97

A structurally unique E2-binding domain activates ubiquitination by the ERAD E2, Ubc7p, through multiple mechanisms.  

PubMed

Cue1p is an integral component of yeast endoplasmic reticulum (ER)-associated degradation (ERAD) ubiquitin ligase (E3) complexes. It tethers the ERAD ubiquitin-conjugating enzyme (E2), Ubc7p, to the ER and prevents its degradation, and also activates Ubc7p via unknown mechanisms. We have now determined the crystal structure of the Ubc7p-binding region (U7BR) of Cue1p with Ubc7p. The U7BR is a unique E2-binding domain that includes three ?-helices that interact extensively with the "backside" of Ubc7p. Residues essential for E2 binding are also required for activation of Ubc7p and for ERAD. We establish that the U7BR stimulates both RING-independent and RING-dependent ubiquitin transfer from Ubc7p. Moreover, the U7BR enhances ubiquitin-activating enzyme (E1)-mediated charging of Ubc7p with ubiquitin. This demonstrates that an essential component of E3 complexes can simultaneously bind to E2 and enhance its loading with ubiquitin. These findings provide mechanistic insights into how ubiquitination can be stimulated. PMID:23665230

Metzger, Meredith B; Liang, Yu-He; Das, Ranabir; Mariano, Jennifer; Li, Shengjian; Li, Jess; Kostova, Zlatka; Byrd, R Andrew; Ji, Xinhua; Weissman, Allan M

2013-05-23

98

Prostaglandin E 2 stimulates ion transport in prairie dog gallbladder  

Microsoft Academic Search

The effects of prostaglandins, and specifically prostaglandin E2, on gallbladder ion transport were examined in the prairie dog. Gallbladders were mounted in an Ussing chamber and baseline short-circuit current, potential difference, and tissue resistance were measured. Addition of arachidonic acid (10-4 M, mucosal surface) produced sustained elevations in short-circuit current and potential difference (P-6 M) resulted in a significant (P2

Kimberly Saunders-Kirkwood; Joe A. Cates; Joel J. Roslyn

1993-01-01

99

Advanced Stirling Convertor (ASC-E2) Characterization Testing  

NASA Technical Reports Server (NTRS)

Testing has been conducted on Advanced Stirling Convertor (ASC-E2) convertors at NASA Glenn Research Center in support of the Advanced Stirling Radioisotope Generator (ASRG) Project. This testing has been conducted to understand sensitivities of convertor parameters due to environmental and operational changes during operation of the ASRG in missions to space. This paper summarizes test results and explains in terms of operation of the ASRG during space missions.

Williams, Zachary D.; Oriti, Salvatore M.

2012-01-01

100

Multicilin drives centriole biogenesis via E2f proteins  

PubMed Central

Multiciliate cells employ hundreds of motile cilia to produce fluid flow, which they nucleate and extend by first assembling hundreds of centrioles. In most cells, entry into the cell cycle allows centrioles to undergo a single round of duplication, but in differentiating multiciliate cells, massive centriole assembly occurs in G0 by a process initiated by a small coiled-coil protein, Multicilin. Here we show that Multicilin acts by forming a ternary complex with E2f4 or E2f5 and Dp1 that binds and activates most of the genes required for centriole biogenesis, while other cell cycle genes remain off. This complex also promotes the deuterosome pathway of centriole biogenesis by activating the expression of deup1 but not its paralog, cep63. Finally, we show that this complex is disabled by mutations in human Multicilin that cause a severe congenital mucociliary clearance disorder due to reduced generation of multiple cilia. By coopting the E2f regulation of cell cycle genes, Multicilin drives massive centriole assembly in epithelial progenitors in a manner required for multiciliate cell differentiation. PMID:24934224

Ma, Lina; Quigley, Ian; Omran, Heymut; Kintner, Chris

2014-01-01

101

Prolactin and aging: X-irradiated and estrogen-induced rat mammary tumorigenesis  

SciTech Connect

Both sexes of inbred WF rats at either 8 or 28-60 weeks of age were exposed to 200 rad whole-body radiation, 2.5 or 5.0 mg 17 beta-estradiol (E2), or both agents The female rats treated with E2 alone or with both X-rays and E2 at 8 weeks of age showed a high incidence of mammary carcinomas (MCA), a large increase in pituitary weight, and a rise in serum prolactin (PRL) levels. However, the same treatments to males did not induce MCA despite a moderate increase in both pituitary weight and serum PRL. Ovariectomy prior to E2 treatment failed to modify the occurrence of MCA or pituitary tumors. When X-rays and E2 were given to female rats at 28-60 weeks of age, pituitary weight, serum PRL levels, and the incidence of MCA were unaffected. When the E2 pellet was kept for the first 24 weeks and withdrawn during the last 12 weeks, the incidence of MCA, pituitary weight, and serum PRL was low. It was concluded that: 1) the pituitary glands of young female rats were susceptible to E2 treatment but were insensitive in older females, and 2) the occurrence of MCA in female rats appeared to be promoted by elevated PRL levels secreted by E2-induced pituitary tumors. Mammary tissue of male rats was less sensitive to PRL levels in the development of MCA.

Ito, A.; Naito, M.; Watanabe, H.; Yokoro, K.

1984-07-01

102

Imperial College London EEE 1L1 Autumn 2009 E2.2 Analogue Electronics E2.2 Analogue Electronics  

E-print Network

Imperial College London ­ EEE 1L1 Autumn 2009 E2.2 Analogue Electronics E2.2 Analogue Electronics Autumn 2009 E2.2 Analogue Electronics What analogue electronics is · Engineering, i.e. the analysis, Instrumentation, ... · Areas of human activity: Industrial, Consumer, Biomedical, ... #12;Imperial College London

Papavassiliou, Christos

103

Intro Unicorns/Tools Trustees Audits E2E v H2E EBE+ E2E to Hand-to-Eye  

E-print Network

Intro Unicorns/Tools Trustees Audits E2E v H2E EBE+ E2E + H2E E2E to Hand-to-Eye Verifiability be malicious · Allies not random, just erratic, uncompliant, befuddled, lazy, malicious (cf J.P. Clark's law

Stark, Philip B.

104

Estrogen Levels in House Wren (Troglodytes aedon) Egg Yolks  

Microsoft Academic Search

Estrogen, when present in early embryonic development, regulates sexual differentiation in the avian nestling and adult. In this study, I developed a procedure to extract and quantify levels (by radioimmunoassay) of the estrogen, 17[beta]-estradiol, in house wren (Troglodytes aedon) egg yolk. Levels of 17[beta]-estradiol found in one clutch of eggs increased with the order of laying, indicating female house wrens

V. BrookWaggoner

1996-01-01

105

Estrogen inhibits ATR signaling to cell cycle checkpoints and DNA repair.  

PubMed

DNA damage activates the ataxia telangiectasia-mutated and Rad3-related (ATR) kinase signal cascade. How this system is restrained is not understood. We find that in estrogen receptor (ER)-positive breast cancer cells, UV or ionizing radiation and hydroxyurea rapidly activate ATR-dependent phosphorylation of endogenous p53 and Chk1. 17-beta-estradiol (E(2)) substantially blocks ATR activity via plasma membrane-localized ERalpha. E(2)/ER reduces the enhanced association of ATR andTopBP1 proteins that follows DNA damage and strongly correlates to ATR activity. E(2) inhibits ATR activation through rapid PI3K/AKT signaling: AKT phosphorylates TopBP1 at Serine 1159, thereby preventing the enhanced association of ATR with TopBP1 after DNA damage. E(2) also inhibits Claspin:Chk1 protein association via AKT phosphorylation of Chk1, preventing Chk1 signaling to the G2/M checkpoint. ATR-phosphorylation of p53 induces p21 transcription, prevented by E(2)/ER. E(2) delays the assembly and prolongs the resolution of gammaH2AX and Rad51 nuclear foci and delays DNA repair. E(2)/ER also increases the chromosomal damage seen from cell exposure to IR. Therefore, the restraint of ATR cascade activation may be a novel estrogen action relevant to breast cancer. PMID:19477925

Pedram, Ali; Razandi, Mahnaz; Evinger, Albert J; Lee, Eva; Levin, Ellis R

2009-07-01

106

Estradiol uptake, toxicity, metabolism, and adverse effects on cadmium-treated amphibian embryos.  

PubMed Central

The exposure of Bufo arenarum embryos to 25 micromol/L 17beta-estradiol (E2) resulted in 100% lethality within 48 hr, whereas 10 micromol//L E2 was the no observed effect concentration value for short-term chronic (7 days) exposure. The toxicity profile curves show that lethal effects were proportional to the E2 concentration and the time of exposure. The E2 uptake resulted in 20.1 ng E2/mg embryo at 8 hr posttreatment, but 67.3% of this value was achieved during the first 30 min of incubation with this estrogen. Regarding metabolism, the embryos synthesize estrone (E1) from E2 by means of 17beta-hydroxysteroid dehydrogenase. Simultaneous treatments of Bufo arenarum embryos with 1 mg/L Cd2+ and 0.1, 1, or 10 micromol/L E2 enhanced the lethality exerted by cadmium in 76.7, 80, and 83.3% of embryos, respectively. The results indicate that estrogenic endocrine disruptors could have an adverse effect on amphibian embryos and enhance the toxic effect of Cd on amphibian embryos. This study points to the possibility of using the AMPHITOX test as a screening method for potential endocrine disruption as well as the combined effects of chemical mixtures. PMID:15175173

Fridman, Osvaldo; Corró, Lucrecia; Herkovits, Jorge

2004-01-01

107

Comparison of the protective effect of melatonin with other antioxidants in the hamster kidney model of estradiol-induced DNA damage.  

PubMed

17beta-Estradiol (E(2)) is a known carcinogen. Estrogen induction of tumors in hamster kidney is a model of estrogen-related carcinogenesis. Melatonin is a well-known antioxidant, free radical scavenger and oncostatic agent. Changes in the levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), an index of DNA damage, were measured in kidneys, liver and testes from hamsters treated with E(2) (75mg/kg b.w.) and collected 5h later. Potential protective effects of melatonin, N-acetylserotonin (NAS), indole-3-propionic acid (IPA) and ascorbic acid (AA) against E(2)-induced DNA damage were tested. The antioxidants were applied in equimolar doses of 64.5 micromol/kg b.w., 2 and 0.5h before and 2 and 4h after E(2) treatment. E(2) treatment caused a significant increase in 8-oxodGuo levels in kidneys, but did not influence significantly the oxidation of guanine bases in liver and testes. Melatonin, IPA and AA, but not NAS, completely prevented E(2)-induced DNA damage in hamster kidneys. It is concluded that melatonin, IPA and AA may be effective in protecting against E(2)-related DNA damage and, consequently, carcinogenesis. PMID:11239965

Karbownik, M; Reiter, R J; Cabrera, J; Garcia, J J

2001-03-01

108

Astro-E2 Magnesium Diboride High Current Leads  

SciTech Connect

The recent discovery of superconducting properties in MgB2 and rapid development of small diameter steel-clad wires has opened up the possibility of enhancing the design of the baseline Astro-E2 high current lead assembly. Replacing YBCO filaments with MgB2 wires and modifying the heat sink location can give much higher margins against quench from temperature oscillations of the 4 K heat sink, although with some overall thermal penalty. The design and performance of a new lead assembly during flight qualification is discussed, with emphasis on thermal, structural, and electrical test results.

Panek, J.S.; Tuttle, J.G.; Marrero, V.; Mustafi, S.; Edmonds, R.; Gray, A.; Riall, S. [Cryogenics and Fluids Branch/Code 552, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2004-06-23

109

Astro-E2 Magnesium Diboride High Current Leads  

NASA Technical Reports Server (NTRS)

The recent discovery of superconducting properties in MgB_2 and rapid development of small diameter steel-clad wires has opened up the possibility of enhancing the design of the baseline Astro-E2 high current lead assembly. Replacing YBCO filaments with MgB_2 wires and modifying the heat sink location can give much higher margins against quench from temperature oscillations of the 4 K heat sink, although wih some overall thermal penalty. The design and performance of a new lead assembly during flight qualification is discussed, with emphasis on thermal, structural, and electrical test results.

Panek, J. S.; Tuttle, J. G.; Riall, S.; Mustafi, S.; Gray, A.; Edmonds, R.; Marrero, V.

2003-01-01

110

E2F6 negatively regulates ultraviolet-induced apoptosis via modulation of BRCA1  

Microsoft Academic Search

E2F6 is believed to repress E2F-responsive genes and therefore plays an important role in cell-cycle regulation. However, the role of E2F6 in the control of apoptosis remains unknown. We show here that the expression of E2F6 was downregulated with a concurrent increase in BRCA1 mRNA and cleaved protein during ultraviolet (UV)-induced apoptosis in human embryonic kidney 293 cells. Moreover, E2F6

W-W Yang; Z-H Wang; Y Zhu; H-T Yang

2007-01-01

111

Effect of lignans isolated from Hernandia nymphaeifolia on estrogenic compounds-induced calcium mobilization in human neutrophils.  

PubMed

The effect of five lignans isolated from Hernandia nymphaeifolia on estrogenic compounds (17beta-estradiol, tamoxifen and clomiphene)-induced Ca(2+) mobilization in human neutrophils was investigated. The five lignans were epi-yangambin, epi-magnolin, epi-aschantin, deoxypodophyllotoxin and yatein. In Ca(2+)-containing medium, the lignans (50-100 microM) inhibited 10 microM 17beta-estradiol- and 5 microM tamoxifen-induced increases in intracellular free Ca(2+) levels ([Ca(2+)](i)) without changing 25 microM clomiphene-induced [Ca(2+)](i) increase. 17beta-estradiol and tamoxifen increased [Ca(2+)](i) by causing Ca(2+) influx and Ca(2+) release because their responses were partly reduced by removing extracellular Ca(2+). In contrast, clomiphene solely induced Ca(2+) release. The effect of the lignans on these two Ca(2+) movement pathways underlying 17beta-estradiol- and tamoxifen-induced [Ca(2+)](i) increases was explored. All the lignans (50-100 microM) inhibited 10 microM 17beta-estradiol-and 5 microM tamoxifen-induced Ca(2+) release, and 17beta-estradiol-induced Ca(2+) influx. However, only 100 microM epi-aschantin was able to reduce tamoxifen-induced Ca(2+) influx while the other lignans had no effect. Collectively, this study shows that the lignans altered estrogenic compounds-induced Ca(2+) signaling in human neutrophils in a multiple manner. PMID:12008094

Chao, Yu-Ying; Jan, Chung-Ren; Ko, Ying-Chin; Chen, Jih-Jung; Jiann, Bang Ping; Lu, Yih-Chau; Chen, Wei-Chung; Su, Warren; Chen, Ih-Sheng

2002-05-17

112

Novel link between E2F1 and Smac/DIABLO: proapoptotic Smac/DIABLO is transcriptionally upregulated by E2F1  

PubMed Central

Deregulated expression of E2F1 not only promotes S-phase entry but also induces apoptosis. Although it has been well documented that E2F1 is able to induce p53-dependent apoptosis via raising ARF activity, the mechanism by which E2F induces p53-independent apoptosis remains unclear. Here we report that E2F1 can directly bind to and activate the promoter of Smac/DIABLO, a mitochondrial proapoptotic gene, through the E2F1-binding sites BS2 (?542 ? ?535 bp) and BS3 (?200 ? ?193 bp). BS2 and BS3 appear to be utilized in combination rather than singly by E2F1 in activation of Smac/DIABLO. Activation of BS2 and BS3 are E2F1-specific, since neither E2F2 nor E2F3 is able to activate BS2 or BS3. Using the H1299 ER-E2F1 cell line where E2F1 activity can be conditionally induced, E2F1 has been shown to upregulate the Smac/DIABLO expression at both mRNA and protein levels upon 4-hydroxytamoxifen treatment, resulting in an enhanced mitochondria-mediated apoptosis. Reversely, reducing the Smac/DIABLO expression by RNA interference significantly diminishes apoptosis induced by E2F1. These results may suggest a novel mechanism by which E2F1 promotes p53-independent apoptosis through directly regulating its downstream mitochondrial apoptosis-inducing factors, such as Smac/DIABLO. PMID:16617145

Xie, Wei; Jiang, Peng; Miao, Lin; Zhao, Ying; Zhimin, Zhai; Qing, Li; Zhu, Wei-guo; Wu, Mian

2006-01-01

113

17?-estradiol regulates giant vesicle formation via estrogen receptor-alpha in human breast cancer cells  

PubMed Central

A significant proportion of the genes regulated by 17-beta-estradiol (E2) via estrogen receptor alpha (ER?) have roles in vesicle trafficking in breast cancer. Intracellular vesicle trafficking and extracellular vesicles have important roles in tumourigenesis. Here we report the discovery of giant (3-42?m) intracellular and extracellular vesicles (GVs) and the role of E2 on vesicle formation in breast cancer (BC) cell lines using three independent live cell imaging techniques. Large diameter vesicles, GVs were also identified in a patient-derived xenograft BC model, and in invasive breast carcinoma tissue. ER?-positive (MCF-7 and T47D) BC cell lines demonstrated a significant increase in GV formation after stimulation with E2 which was reversed by tamoxifen. ER?-negative (MDA-MB-231 and MDA-MB-468) BC cell lines produced GVs independently of E2 and tamoxifen. These results indicate the existence of both intracellular and extracellular vesicles with considerably larger dimensions than generally recognised with BC cells and suggest that the GVs are regulated by E2 via ER? in ER?-positive BC but by E2-independent mechanisms in ER-ve BC. PMID:24931391

Wright, Paul K; Jones, Sarah Bowen; Ardern, Nicholas; Ward, Rebecca; Clarke, Robert B; Sotgia, Federica; Lisanti, Michael P; Landberg, Goran; Lamb, Rebecca

2014-01-01

114

Structure-function relationship of estrogen receptor alpha and beta: impact on human health.  

PubMed

17Beta-estradiol (E2) controls many aspects of human physiology, including development, reproduction and homeostasis, through regulation of the transcriptional activity of its cognate receptors (ERs). The crystal structures of ERs with agonists and antagonists and the use of transgenic animals have revealed much about how hormone binding influences ER conformation(s) and how this conformation(s), in turn, influences the interaction of ERs with co-activators or co-repressors and hence determines ER binding to DNA and cellular outcomes. This information has helped to shed light on the connection between E2 and the development or progression of numerous diseases. Current therapeutic strategy in the treatment of E2-related pathologies relies on the modulation of ER trancriptional activity by anti-estrogens; however, data accumulated during the last five years reveal that ER activities are not only restricted to the nucleus. ERs are very mobile proteins continuously shuttling between protein targets located within various cellular compartments (e.g., membrane, nucleus). This allows E2 to generate different and synergic signal transduction pathways (i.e., non-genomic and genomic) which provide plasticity for cell response to E2. Understanding the structural basis and the molecular mechanisms by which ER transduce E2 signals in target cells will allow to create new pharmacologic therapies aimed at the treatment of a variety of human diseases affecting the cardiovascular system, the reproductive system, the skeletal system, the nervous system, the mammary gland, and many others. PMID:16914190

Ascenzi, Paolo; Bocedi, Alessio; Marino, Maria

2006-08-01

115

Time course of the estradiol-dependent induction of oxytocin receptor binding in the ventromedial hypothalamic nucleus of the rat  

SciTech Connect

Oxytocin (OT) transmission is involved in the steroid-dependent display of sexual receptivity in rats. One of the biochemical processes stimulated by the ovarian steroid 17 beta-estradiol (E2) that is relevant to reproduction is the induction of OT receptor binding in the ventromedial hypothalamic nucleus (VMN). The purpose of these experiments was to determine if E2-induced changes in OT receptor binding in the VMN occur within a time frame relevant to cyclic changes in ovarian steroid secretion. OT receptor binding was measured in the VMN of ovariectomized rats implanted for 0-96 h with E2-containing Silastic capsules. The rate of decay of OT receptor binding was measured in another group of animals 6-48 h after capsule removal. Receptors were labeled with the specific OT receptor antagonist ({sup 125}I)d(CH2)5(Tyr(Me)2,Thr4,Tyr-NH2(9))OVT, and binding was measured with quantitative autoradiographic methods. In addition, plasma E2 levels and uterine weights were assessed in animals from each treatment condition. Significant increases in E2-dependent OT receptor binding and uterine weight occurred within 24 h of steroid treatment. After E2 withdrawal, OT receptor binding and uterine weight decreased significantly within 24 h. These results are consistent with the hypothesis that steroid modulation of OT receptor binding is necessary for the induction of sexual receptivity.

Johnson, A.E.; Ball, G.F.; Coirini, H.; Harbaugh, C.R.; McEwen, B.S.; Insel, T.R. (National Institute of Mental Health, Poolesville, MD (USA))

1989-09-01

116

Estradiol affects liver mitochondrial function in ovariectomized and tamoxifen-treated ovariectomized female rats  

SciTech Connect

Given the tremendous importance of mitochondria to basic cellular functions as well as the critical role of mitochondrial impairment in a vast number of disorders, a compelling question is whether 17{beta}-estradiol (E2) modulates mitochondrial function. To answer this question we exposed isolated liver mitochondria to E2. Three groups of rat females were used: control, ovariectomized and ovariectomized treated with tamoxifen. Tamoxifen has antiestrogenic effects in the breast tissue and is the standard endocrine treatment for women with breast cancer. However, under certain circumstances and in certain tissues, tamoxifen can also exert estrogenic agonist properties. We observed that at basal conditions, ovariectomy and tamoxifen treatment do not induce any statistical alteration in oxidative phosphorylation system and respiratory chain parameters. Furthermore, tamoxifen treatment increases the capacity of mitochondria to accumulate Ca{sup 2+} delaying the opening of the permeability transition pore. The presence of 25 {mu}M E2 impairs respiration and oxidative phosphorylation system these effects being similar in all groups of animals studied. Curiously, E2 protects against lipid peroxidation and increases the production of H{sub 2}O{sub 2} in energized mitochondria of control females. Our results indicate that E2 has in general deleterious effects that lead to mitochondrial impairment. Since mitochondrial dysfunction is a triggering event of cell degeneration and death, the use of exogenous E2 must be carefully considered.

Moreira, Paula I. [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal); Institute of Physiology, Faculty of Medicine, University of Coimbra, 3005-504 Coimbra (Portugal); Custodio, Jose B.A. [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal); Institute of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3005-504 Coimbra (Portugal); Nunes, Elsa [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal); Institute of Physiology, Faculty of Medicine, University of Coimbra, 3005-504 Coimbra (Portugal); Moreno, Antonio [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal); Department of Zoology, Faculty of Sciences and Technology, University of Coimbra, 3005-504 Coimbra (Portugal); Institute of Marine Research, University of Coimbra, 3005-504 Coimbra (Portugal); Seica, Raquel [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal); Institute of Physiology, Faculty of Medicine, University of Coimbra, 3005-504 Coimbra (Portugal); Oliveira, Catarina R. [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal); Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3005-504 Coimbra (Portugal); Santos, Maria S. [Center for Neuroscience and Cell Biology, University of Coimbra, 3005-504 Coimbra (Portugal) and Department of Zoology, Faculty of Sciences and Technology, University of Coimbra, 3005-504 Coimbra (Portugal)]. E-mail: mssantos@ci.uc.pt

2007-05-15

117

HER2/Neu tumorigenesis and metastasis is regulated by E2F activator transcription factors.  

PubMed

HER2/Neu is amplified and overexpressed in a large proportion of human breast cancers, but the signaling pathways that contribute to tumor development and metastatic progression are not completely understood. Using gene expression data and pathway signatures, we predicted a role for activator E2F transcription factors in Neu-induced tumors. This was genetically tested by interbreeding Neu transgenics with knockouts of the three activator E2Fs. Loss of any E2F delayed Neu-induced tumor onset. E2F1 loss accelerated tumor growth, while E2F2 and E2F3 loss did not. Strikingly, it was observed that loss of E2F1 or E2F2 significantly reduced the metastatic capacity of the tumor and this was associated with a reduction in circulating tumor cells in the E2F2 knockout. Gene expression analysis between the tumors in the various E2F-mutant backgrounds revealed that there was extensive compensation by other E2F family members in the individual knockouts, underscoring the importance of the E2Fs in HER2/Neu-induced tumors. Extension to HER2-positive (HER2+) human breast cancer revealed a number of HER2+ subtypes based on E2F activity with differences in relapse-free survival times. Taken together, these data demonstrate that the E2F transcription factors are integral to HER2+ tumor development and progression. PMID:24362522

Andrechek, E R

2015-01-01

118

Search for methyl carbamate in W51e2  

NASA Astrophysics Data System (ADS)

Complex organic molecules containing up to 10 atoms have been detected in several hot molecular clouds such as Orion or SgrB2. Glycine (NH2CH2COOH), the simplest amino acid, has been extensively searched in hot cores and in molecular outflows but has not been firmly detected yet. Using the 30m IRAM antenna at Pico Veleta, we have searched for the methyl carbamate (NH2COOCH3), the isomere of glycine, in the hot molecular cloud W51e2 and in the intermediate mass protostar IRAS21391+58502. This molecule, if present in molecular clouds, should be more favorable to detect than glycine thanks to its strong dipole moment. This poster presents the results from these observations.

Demyk, Karine; Wlodarczak, Georges; Dartois, Emmanuel

2004-12-01

119

Triply differential (e,2e) studies of phenol  

NASA Astrophysics Data System (ADS)

We have measured (e,2e) triple differential cross sections (TDCS) for the electron-impact ionisation of phenol with coplanar asymmetrical kinematics for an incident electron energy of 250 eV. Experimental measurements of the angular distribution of the slow outgoing electrons at 20 eV are obtained when the incident electron scatters through angles of -5°, -10°, and -15°, respectively. The TDCS data are compared with calculations performed within the molecular 3-body distorted wave model. In this case, a mixed level of agreement, that was dependent on the kinematical condition being probed, was observed between the theoretical and experimental results in the binary peak region. The experimental intensity of the recoil features under all kinematical conditions was relatively small, but was still largely underestimated by the theoretical calculations.

da Silva, G. B.; Neves, R. F. C.; Chiari, L.; Jones, D. B.; Ali, E.; Madison, D. H.; Ning, C. G.; Nixon, K. L.; Lopes, M. C. A.; Brunger, M. J.

2014-09-01

120

(e, 2e) processes on Ne, Ar and Xe targets  

NASA Astrophysics Data System (ADS)

Recently, there have been several attempts to explain the features of triple differential cross section (TDCS) for the (e, 2e) processes on inert targets Ne, Ar and Xe but there are still certain discrepancies in theoretical results and measurements, which require more theoretical efforts to understand the collision dynamics of these targets. We present in this paper the results of our modified distorted wave Born approximation (DWBA) calculation of TDCS for the ionization of Ne (2p), Ar (3p) and Xe (5p) targets. We modify the standard DWBA formalism by including the correlation-polarization potential (which is function of electron density) and compare our computed results with the available experimental and theoretical data. We observe that the polarization potential is able to improve the agreement with experimental results.

Purohit, G.; Patidar, Vinod; Sud, K. K.

2010-06-01

121

Three body effects in low energy (e,2e) processes  

SciTech Connect

Within the last two years a number of highly refined measurements have been performed on H targets which have yielded accurate absolute data for a range of energies and geometries and it would appear that the experimental situation for this, the simplest of atomic targets is now resolved. The theoretical situation is however far from satisfactory and in this paper we will analysis some of the main approaches and characterize their strengths and their weaknesses. We have developed a numerical method which allows us to evaluate triple differential cross sections (TDCS) using the most complex position dependent analytic ansatz wave function and we will present results, using this for low energy (e,2e) processes. We will see that this approach fails when incident channel effects, such as target polarization are likely to be strong.

Rasch, J. [Institut de Physique, Laboratoire de Physique Moleculaire et des Collisions, Technopole Metz 2000, Rue Arago (France); Whelan, Colm T. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge, CB3 9EW (United Kingdom)

1999-06-10

122

Triply differential (e,2e) studies of phenol.  

PubMed

We have measured (e,2e) triple differential cross sections (TDCS) for the electron-impact ionisation of phenol with coplanar asymmetrical kinematics for an incident electron energy of 250 eV. Experimental measurements of the angular distribution of the slow outgoing electrons at 20 eV are obtained when the incident electron scatters through angles of -5°, -10°, and -15°, respectively. The TDCS data are compared with calculations performed within the molecular 3-body distorted wave model. In this case, a mixed level of agreement, that was dependent on the kinematical condition being probed, was observed between the theoretical and experimental results in the binary peak region. The experimental intensity of the recoil features under all kinematical conditions was relatively small, but was still largely underestimated by the theoretical calculations. PMID:25273437

da Silva, G B; Neves, R F C; Chiari, L; Jones, D B; Ali, E; Madison, D H; Ning, C G; Nixon, K L; Lopes, M C A; Brunger, M J

2014-09-28

123

Dynamical (e,2e) studies of tetrahydrofurfuryl alcohol  

NASA Astrophysics Data System (ADS)

Cross section data for electron scattering from DNA are important for modelling radiation damage in biological systems. Triply differential cross sections for the electron impact ionization of the highest occupied outer valence orbital of tetrahydrofurfuryl alcohol, which can be considered as an analogue to the deoxyribose backbone molecule in DNA, have been measured using the (e,2e) technique. The measurements have been performed with coplanar asymmetric kinematics at an incident electron energy of 250 eV, an ejected electron energy of 20 eV, and at scattered electron angles of -5°, -10°, and -15°. Experimental results are compared with corresponding theoretical calculations performed using the molecular 3-body distorted wave model. Some important differences are observed between the experiment and calculations.

Bellm, S. M.; Builth-Williams, J. D.; Jones, D. B.; Chaluvadi, Hari; Madison, D. H.; Ning, C. G.; Wang, F.; Ma, X. G.; Lohmann, B.; Brunger, M. J.

2012-06-01

124

Extending PT symmetry from Heisenberg algebra to E2 algebra  

E-print Network

The E2 algebra has three elements, J, u, and v, which satisfy the commutation relations [u,J]=iv, [v,J]=-iu, [u,v]=0. We can construct the Hamiltonian H=J^2+gu, where g is a real parameter, from these elements. This Hamiltonian is Hermitian and consequently it has real eigenvalues. However, we can also construct the PT-symmetric and non-Hermitian Hamiltonian H=J^2+igu, where again g is real. As in the case of PT-symmetric Hamiltonians constructed from the elements x and p of the Heisenberg algebra, there are two regions in parameter space for this PT-symmetric Hamiltonian, a region of unbroken PT symmetry in which all the eigenvalues are real and a region of broken PT symmetry in which some of the eigenvalues are complex. The two regions are separated by a critical value of g.

Carl M. Bender; R. J. Kalveks

2010-09-16

125

DNA-binding and trans-activation properties of Drosophila E2F and DP proteins.  

PubMed Central

The temporal activation of E2F transcriptional activity appears to be an important component of the mechanisms that prepare mammalian cells for DNA replication. Regulation of E2F activity appears to be a highly complex process, and the dissection of the E2F pathway will be greatly facilitated by the ability to use genetic approaches. We report the isolation of two Drosophila genes that can stimulate E2F-dependent transcription in Drosophila cells. One of these genes, dE2F, contains three domains that are highly conserved in the human homologs E2F-1, E2F-2, and E2F-3. Interestingly, one of these domains is highly homologous to the retinoblastoma protein (RB)-binding sequences of human E2F genes. The other gene, dDP, is closely related to the human DP-1 and DP-2 genes. We demonstrate that dDP and dE2F interact and cooperate to give sequence-specific DNA binding and optimal trans-activation. These features suggest that endogenous Drosophila E2F, like human E2F, may be composed of heterodimers and may be regulated by RB-like proteins. The isolation of these genes will provide important reagents for the genetic analysis of the E2F pathway. Images PMID:8022787

Dynlacht, B D; Brook, A; Dembski, M; Yenush, L; Dyson, N

1994-01-01

126

The influence of metabolism on the genotoxicity of catechol estrogens in three cultured cell lines.  

PubMed

The 2- and 4-hydroxy metabolites of 17beta-estradiol (E2) and estrone (E1) are important for E2-mediated carcinogenesis due to the formation of genotoxic ortho-quinone metabolites. To assess the importance of metabolic conjugation for their genotoxicity, the DNA strand-breaking activity of the four catechol estrogens was determined in three cell lines with different activities of catechol-O-methyltransferase (COMT) and UDP-glucuronosyltransferase (UGT). Most DNA strand breaks were observed in V79 cells, which lack these metabolic activities. 2- and 4-hydroxy-E2 were 2.5 times more genotoxic than 2- and 4-hydroxy-E1. MCF-7 cells exhibit COMT activity, and the incidence of DNA strand breaks decreased with increasing methylation; only the 4-hydroxy metabolites of E1 and E2, which were poor substrates of COMT, exhibited low genotoxicity. HepG2 cells converted the catechol and methoxy metabolites of E2 to the respective E1 metabolites by 17beta-hydroxysteroid dehydrogenase (HSD). Moreover, methylation and glucuronidation took place. Only 4-hydroxy-E1 elicited a weak genotoxic response in these cells. The extensive metabolism in HepG2 cells is proposed to account for the failure of catechol estrogens to induce DNA strand breaks. Thus, metabolism by COMT and UGT and, to a minor extent, by HSD is a major determinant for the genotoxicity of catechol estrogens in target cells. PMID:18618478

Gerstner, Silke; Glasemann, Dörte; Pfeiffer, Erika; Metzler, Manfred

2008-07-01

127

Global identification of genes regulated by estrogen signaling and demethylation in MCF-7 breast cancer cells  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Estrogen signaling and demethylation can both control gene expression in breast cancers. Black-Right-Pointing-Pointer Cross-talk between these mechanisms is investigated in human MCF-7 breast cancer cells. Black-Right-Pointing-Pointer 137 genes are influenced by both 17{beta}-estradiol and demethylating agent 5-aza-2 Prime -deoxycytidine. Black-Right-Pointing-Pointer A set of genes is identified as targets of both estrogen signaling and demethylation. Black-Right-Pointing-Pointer There is no direct molecular interplay of mediators of estrogen and epigenetic signaling. -- Abstract: Estrogen signaling and epigenetic modifications, in particular DNA methylation, are involved in regulation of gene expression in breast cancers. Here we investigated a potential regulatory cross-talk between these two pathways by identifying their common target genes and exploring underlying molecular mechanisms in human MCF-7 breast cancer cells. Gene expression profiling revealed that the expression of approximately 140 genes was influenced by both 17{beta}-estradiol (E2) and a demethylating agent 5-aza-2 Prime -deoxycytidine (DAC). Gene ontology (GO) analysis suggests that these genes are involved in intracellular signaling cascades, regulation of cell proliferation and apoptosis. Based on previously reported association with breast cancer, estrogen signaling and/or DNA methylation, CpG island prediction and GO analysis, we selected six genes (BTG3, FHL2, PMAIP1, BTG2, CDKN1A and TGFB2) for further analysis. Tamoxifen reverses the effect of E2 on the expression of all selected genes, suggesting that they are direct targets of estrogen receptor. Furthermore, DAC treatment reactivates the expression of all selected genes in a dose-dependent manner. Promoter CpG island methylation status analysis revealed that only the promoters of BTG3 and FHL2 genes are methylated, with DAC inducing demethylation, suggesting DNA methylation directs repression of these genes in MCF-7 cells. In a further analysis of the potential interplay between estrogen signaling and DNA methylation, E2 treatment showed no effect on the methylation status of these promoters. Additionally, we show that the ER{alpha} recruitment occurs at the FHL2 promoter in an E2- and DAC-independent fashion. In conclusion, we identified a set of genes regulated by both estrogen signaling and DNA methylation. However, our data does not support a direct molecular interplay of mediators of estrogen and epigenetic signaling at promoters of regulated genes.

Putnik, Milica, E-mail: milica.putnik@ki.se [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden)] [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden); Zhao, Chunyan, E-mail: chunyan.zhao@ki.se [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden)] [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden); Gustafsson, Jan-Ake, E-mail: jan-ake.gustafsson@ki.se [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden) [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden); Department of Biology and Biochemistry, Science and Engineering Research Center Bldg, University of Houston, Houston, TX 77204-5056 (United States); Dahlman-Wright, Karin, E-mail: karin.dahlman-wright@ki.se [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden)] [Department of Biosciences and Nutrition, Novum, Karolinska Institutet, Huddinge S-14183 (Sweden)

2012-09-14

128

17 CFR 270.6e-2 - Exemptions for certain variable life insurance separate accounts.  

Code of Federal Regulations, 2011 CFR

...false Exemptions for certain variable life insurance separate accounts. 270.6e-2...6e-2 Exemptions for certain variable life insurance separate accounts. ...account is established and maintained by a life insurance company pursuant to the...

2011-04-01

129

17 CFR 270.6e-2 - Exemptions for certain variable life insurance separate accounts.  

Code of Federal Regulations, 2012 CFR

...false Exemptions for certain variable life insurance separate accounts. 270.6e-2...6e-2 Exemptions for certain variable life insurance separate accounts. ...account is established and maintained by a life insurance company pursuant to the...

2012-04-01

130

17 CFR 270.6e-2 - Exemptions for certain variable life insurance separate accounts.  

...false Exemptions for certain variable life insurance separate accounts. 270.6e-2...6e-2 Exemptions for certain variable life insurance separate accounts. ...account is established and maintained by a life insurance company pursuant to the...

2014-04-01

131

17 CFR 270.6e-2 - Exemptions for certain variable life insurance separate accounts.  

Code of Federal Regulations, 2010 CFR

...false Exemptions for certain variable life insurance separate accounts. 270.6e-2...6e-2 Exemptions for certain variable life insurance separate accounts. ...account is established and maintained by a life insurance company pursuant to the...

2010-04-01

132

17 CFR 270.6e-2 - Exemptions for certain variable life insurance separate accounts.  

Code of Federal Regulations, 2013 CFR

...false Exemptions for certain variable life insurance separate accounts. 270.6e-2...6e-2 Exemptions for certain variable life insurance separate accounts. ...account is established and maintained by a life insurance company pursuant to the...

2013-04-01

133

Molecular Links between the E2 Envelope Glycoprotein and Nucleocapsid Core in Sindbis Virus  

E-print Network

as alarming outbreaks of Chikungunya highlight the threat of global travel and underscore the need to better, amino acids; cdE1, cytoplasmic domain of E1; cdE2, cytoplasmic domain of E2; CHIKV, Chikungunya virus

Baker, Timothy S.

134

The role of E2f4 in cell cycle exit and bone development  

E-print Network

Members of the E2F family of transcription factors are critical downstream effectors of the pocket protein family and mediate the regulation of genes required for cellular proliferation. The repressive E2Fs act in association ...

Miller, Emily S. (Emily Sun Young)

2009-01-01

135

Yeast-expressed classical swine fever virus glycoprotein E2 induces a protective immune response  

Microsoft Academic Search

Classical swine fever (CSF) is an economically important swine disease worldwide. The glycoprotein E2 of classical swine fever virus (CSFV) is a viral antigen that can induce a protective immune response against CSF. A recombinant E2 protein was constructed using the yeast Pichia pastoris expression system and evaluated for its vaccine efficacy. The yeast-expressed E2 (yE2) was shown to have

Guang-Jan Lin; Ting-Yu Liu; Yu-Yao Tseng; Zeng-Weng Chen; Chia-Chin You; Shih-Ling Hsuan; Maw-Sheng Chien; Chienjin Huang

2009-01-01

136

In vivo delivery of bovine viral diahorrea virus, E2 protein using hollow mesoporous silica nanoparticles  

NASA Astrophysics Data System (ADS)

Our work focuses on the application of mesoporous silica nanoparticles as a combined delivery vehicle and adjuvant for vaccine applications. Here we present results using the viral protein, E2, from bovine viral diarrhoea virus (BVDV). BVDV infection occurs in the target species of cattle and sheep herds worldwide and is therefore of economic importance. E2 is a major immunogenic determinant of BVDV and is an ideal candidate for the development of a subunit based nanovaccine using mesoporous silica nanoparticles. Hollow type mesoporous silica nanoparticles with surface amino functionalisation (termed HMSA) were characterised and assessed for adsorption and desorption of E2. A codon-optimised version of the E2 protein (termed Opti-E2) was produced in Escherichia coli. HMSA (120 nm) had an adsorption capacity of 80 ?g Opti-E2 per mg HMSA and once bound E2 did not dissociate from the HMSA. Immunisation studies in mice with a 20 ?g dose of E2 adsorbed to 250 ?g HMSA was compared to immunisation with Opti-E2 (50 ?g) together with the traditional adjuvant Quillaja saponaria Molina tree saponins (QuilA, 10 ?g). The humoral responses with the Opti-E2/HMSA nanovaccine although slightly lower than those obtained for the Opti-E2 + QuilA group demonstrated that HMSA particles are an effective adjuvant that stimulated E2-specific antibody responses. Importantly the cell-mediated immune responses were consistently high in all mice immunised with Opti-E2/HMSA nanovaccine formulation. Therefore we have shown the Opti-E2/HMSA nanoformulation acts as an excellent adjuvant that gives both T-helper 1 and T-helper 2 mediated responses in a small animal model. This study has provided proof-of-concept towards the development of an E2 subunit nanoparticle based vaccine.Our work focuses on the application of mesoporous silica nanoparticles as a combined delivery vehicle and adjuvant for vaccine applications. Here we present results using the viral protein, E2, from bovine viral diarrhoea virus (BVDV). BVDV infection occurs in the target species of cattle and sheep herds worldwide and is therefore of economic importance. E2 is a major immunogenic determinant of BVDV and is an ideal candidate for the development of a subunit based nanovaccine using mesoporous silica nanoparticles. Hollow type mesoporous silica nanoparticles with surface amino functionalisation (termed HMSA) were characterised and assessed for adsorption and desorption of E2. A codon-optimised version of the E2 protein (termed Opti-E2) was produced in Escherichia coli. HMSA (120 nm) had an adsorption capacity of 80 ?g Opti-E2 per mg HMSA and once bound E2 did not dissociate from the HMSA. Immunisation studies in mice with a 20 ?g dose of E2 adsorbed to 250 ?g HMSA was compared to immunisation with Opti-E2 (50 ?g) together with the traditional adjuvant Quillaja saponaria Molina tree saponins (QuilA, 10 ?g). The humoral responses with the Opti-E2/HMSA nanovaccine although slightly lower than those obtained for the Opti-E2 + QuilA group demonstrated that HMSA particles are an effective adjuvant that stimulated E2-specific antibody responses. Importantly the cell-mediated immune responses were consistently high in all mice immunised with Opti-E2/HMSA nanovaccine formulation. Therefore we have shown the Opti-E2/HMSA nanoformulation acts as an excellent adjuvant that gives both T-helper 1 and T-helper 2 mediated responses in a small animal model. This study has provided proof-of-concept towards the development of an E2 subunit nanoparticle based vaccine. Electronic supplementary information (ESI) available: Desorption studies of Opti-E2 bound HMSA. See DOI: 10.1039/c4nr01202j

Mahony, D.; Cavallaro, A. S.; Mody, K. T.; Xiong, L.; Mahony, T. J.; Qiao, S. Z.; Mitter, N.

2014-05-01

137

Prostaglandin E2-induced inflammation: Relevance of prostaglandin E receptors.  

PubMed

Prostaglandin E2 (PGE2) is one of the most typical lipid mediators produced from arachidonic acid (AA) by cyclooxygenase (COX) as the rate-limiting enzyme, and acts on four kinds of receptor subtypes (EP1-EP4) to elicit its diverse actions including pyrexia, pain sensation, and inflammation. Recently, the molecular mechanisms underlying the PGE2 actions mediated by each EP subtype have been elucidated by studies using mice deficient in each EP subtype as well as several compounds highly selective to each EP subtype, and their findings now enable us to discuss how PGE2 initiates and exacerbates inflammation at the molecular level. Here, we review the recent advances in PGE2 receptor research by focusing on the activation of mast cells via the EP3 receptor and the control of helper T cells via the EP2/4 receptor, which are the molecular mechanisms involved in PGE2-induced inflammation that had been unknown for many years. We also discuss the roles of PGE2 in acute inflammation and inflammatory disorders, and the usefulness of anti-inflammatory therapies that target EP receptors. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: Analysis and biological relevance". PMID:25038274

Kawahara, Kohichi; Hohjoh, Hirofumi; Inazumi, Tomoaki; Tsuchiya, Soken; Sugimoto, Yukihiko

2014-07-17

138

STS-70 Launch - Nikon E-2 Digital Image  

NASA Technical Reports Server (NTRS)

This test images was taken with a Nikon E-2 Digital Imaging System camera and are provided courtesy of Nikon (GIF 450x450 JPEG 1280x1000): The second Shuttle launch in 16 days hurtles off the pad into a sweltering summer sky. The unstable weather typical to Florida in the summertime didn't have a chance to coalesce and impact this morning's launch window, and the Space Shuttle Discovery began its planned seven-day, 22-hour flight on Mission STS-70 from Launch Pad 39B at 9:41:55.078 a.m. EDT, just seconds off schedule. On board for Discovery's 21st spaceflight are a crew of five: Commander Terence 'Tom' Henricks; Pilot Kevin R. Kregel; and Mission Specialists Nancy Jane Currie, Donald A. Thomas and Mary Ellen Weber. The crew's primary objective during the 70th Shuttle flight is to deploy the Tracking and Data Relay Satellite (TDRS-G), which will join a constellation of other TDRS spacecraft already on orbit. TDRS-G is destined to become an on- orbit, fully operational 'ready reserve' satellite, available along with one other ready reserve TDRS spacecraft to back up the two primary TDRS satellites positions, TDRS East over the Atlantic Ocean and TDRS West over the Pacific. Assured capability of the TDRS communications network is essential for linking Earth-orbiting spacecraft such as the Shuttle and the Hubble Space Telescope with the ground.

1995-01-01

139

STS-70 Launch - Nikon E-2 Digital Image  

NASA Technical Reports Server (NTRS)

This test image was taken with a Nikon E-2 Digital Imaging System camera and are provided courtesy of Nikon (GIF 450x450 JPEG 1280x1000): The second Shuttle launch in 16 days hurtles off the pad into a sweltering summer sky. The unstable weather typical to Florida in the summertime didn't have a chance to coalesce and impact this morning's launch window, and the Space Shuttle Discovery began its planned seven-day, 22-hour flight on Mission STS-70 from Launch Pad 39B at 9:41:55.078 a.m. EDT, just seconds off schedule. On board for Discovery's 21st spaceflight are a crew of five: Commander Terence 'Tom' Henricks; Pilot Kevin R. Kregel; and Mission Specialists Nancy Jane Currie, Donald A. Thomas and Mary Ellen Weber. The crew's primary objective during the 70th Shuttle flight is to deploy the Tracking and Data Relay Satellite (TDRS-G), which will join a constellation of other TDRS spacecraft already on orbit. TDRS-G is destined to become an on- orbit, fully operational 'ready reserve' satellite, available along with one other ready reserve TDRS spacecraft to back up the two primary TDRS satellites positions, TDRS East over the Atlantic Ocean and TDRS West over the Pacific. Assured capability of the TDRS communications network is essential for linking Earth-orbiting spacecraft such as the Shuttle and the Hubble Space Telescope with the ground.

1995-01-01

140

Prostaglandin E2 Prevents Disuse-Induced Cortical Bone Loss  

NASA Technical Reports Server (NTRS)

The object of this study was to determine whether prostaglandin E2 (PGE2) can prevent disuse (underloaded)-induced cortical bone loss as well as add extra bone to underloaded bones. Thirteen-month-old retired female Sprague-Dawley breeders served as controls or were subjected to simultaneous right hindlimb immobilization by bandaging and daily subcutaneous doses of 0, 1, 3, or 6 mg PGE2/kg/d for two and six weeks. Histomorphometric analyses were performed on double-fluorescent labeled undecalcified tibial shaft sections (proximal to the tibiofibular junction). Disuse-induced cortical bone loss occurred by enlarging the marrow cavity and increasing intracortical porosity. PGE2 treatment of disuse shafts further increased intracortical porosity above that in disuse alone controls. This bone loss was counteracted by enhancement of periosteal and corticoendosteal bone formation. Stimulation of periosteal and corticoendosteal bone formation slightly enlarged the total tissue (cross-sectional) area and inhibited marrow cavity enlargement. These PGE2-induced activities netted the same percentage of cortical bone with a different distribution than the beginning and age related controls. These findings indicate the PGE2-induced increase in bone formation compensated for the disuse and PGE2-induced bone loss, and thus prevented immobilization induced bone loss.

Jee, Webster S. S.; Akamine, T.; Ke, Hua Zhu; Li, Xiao Jian; Tang, L. Y.; Zeng, Q. Q.

1992-01-01

141

Magnesium Ions Enhance the Transfer of Human Papillomavirus E2 Protein from Non-specific to  

E-print Network

Magnesium Ions Enhance the Transfer of Human Papillomavirus E2 Protein from Non University of Bristol, Bristol BS8 1TD, UK The human papillomavirus 16 E2 protein binds to four speci®c DNA how E2 is able to direct human papillomavirus transcription and DNA replica- tion in intact cells

Gaston, Kevin

142

The function of E2F6 in the Polycomb complex  

E-print Network

The E2F family of transcription factors are known cell cycle regulators that function at the G1/S transition. Unlike other E2Fs, E2F6 does not activate transcription and is not regulated by pocket protein binding. Instead, ...

Courel, María F. (María Federica)

2005-01-01

143

E2F Activators Signal and Maintain Centrosome Amplification in Breast Cancer Cells  

PubMed Central

Centrosomes ensure accurate chromosome segregation by directing spindle bipolarity. Loss of centrosome regulation results in centrosome amplification, multipolar mitosis and aneuploidy. Since centrosome amplification is common in premalignant lesions and breast tumors, it is proposed to play a central role in breast tumorigenesis, a hypothesis that remains to be tested. The coordination between the cell and centrosome cycles is of paramount importance to maintain normal centrosome numbers, and the E2Fs may be responsible for regulating these cycles. However, the role of E2F activators in centrosome amplification is unclear. Because E2Fs are deregulated in Her2+ cells displaying centrosome amplification, we addressed whether they signal this abnormal process. Knockdown of E2F1 or E2F3 in Her2+ cells decreased centrosome amplification without significantly affecting cell cycle progression, whereas the overexpression of E2F1, E2F2, or E2F3 increased centrosome amplification in MCF10A mammary epithelial cells. Our results revealed that E2Fs affect the expression of proteins, including Nek2 and Plk4, known to influence the cell/centrosome cycles and mitosis. Downregulation of E2F3 resulted in cell death and delays/blocks in cytokinesis, which was reversed by Nek2 overexpression. Nek2 overexpression enhanced centrosome amplification in Her2+ breast cancer cells silenced for E2F3, revealing a role for the E2F activators in maintaining centrosome amplification in part through Nek2. PMID:24797070

Lee, Mi-Young; Moreno, Carlos S.

2014-01-01

144

Intestinal hyperplasia induced by simian virus 40 large tumor antigen requires E2F2.  

PubMed

The simian virus 40 large T antigen contributes to neoplastic transformation, in part, by targeting the Rb family of tumor suppressors. There are three known Rb proteins, pRb, p130, and p107, all of which block the cell cycle by preventing the transcription of genes regulated by the E2F family of transcription factors. T antigen interacts directly with Rb proteins and disrupts Rb-E2F complexes both in vitro and in cultured cells. Consequently, T antigen is thought to inhibit transcriptional repression by the Rb family proteins by disrupting their interaction with E2F proteins, thus allowing E2F-dependent transcription and the expression of cellular genes needed for entry into S phase. This model predicts that active E2F-dependent transcription is required for T-antigen-induced transformation. To test this hypothesis, we have examined the status of Rb-E2F complexes in murine enterocytes. Previous studies have shown that T antigen drives enterocytes into S phase, resulting in intestinal hyperplasia, and that the induction of enterocyte proliferation requires T-antigen binding to Rb proteins. In this paper, we show that normal growth-arrested enterocytes contain p130-E2F4 complexes and that T-antigen expression destroys these complexes, most likely by stimulating p130 degradation. Furthermore, unlike their normal counterparts, enterocytes expressing T antigen contain abundant levels of E2F2 and E2F3a. Concomitantly, T-antigen-induced intestinal proliferation is reduced in mice lacking either E2F2 alone or both E2F2 and E2F3a, but not in mice lacking E2F1. These studies support a model in which T antigen eliminates Rb-E2F repressive complexes so that specific activator E2Fs can drive S-phase entry. PMID:17855529

Sáenz-Robles, M Teresa; Markovics, Jennifer A; Chong, Jean-Leon; Opavsky, Rene; Whitehead, Robert H; Leone, Gustavo; Pipas, James M

2007-12-01

145

DNA Damage Signals through Differentially Modified E2F1 Molecules To Induce Apoptosis  

PubMed Central

E2F transcription can lead to cell proliferation or apoptosis, indicating that E2Fs control opposing functions. In a similar manner, DNA double-strand breaks can signal to induce cell cycle arrest or apoptosis. Specifically, pRB is activated following DNA damage, allowing it to bind to E2Fs and block transcription at cell cycle promoters; however, E2F1 is simultaneously activated, leading to transcription at proapoptotic promoters. We examined this paradoxical control of E2F transcription by studying how E2F1's interaction with pRB is regulated following DNA damage. Our work reveals that DNA damage signals create multiple forms of E2F1 that contain mutually exclusive posttranslational modifications. Specifically, E2F1 phospho-serine 364 is found only in complex with pRB, while E2F1 phosphorylation at serine 31 and acetylation function to create a pRB-free form of E2F1. Both pRB-bound and pRB-free modifications on E2F1 are essential for the activation of TA-p73 and the maximal induction of apoptosis. Chromatin immunoprecipitation demonstrated that E2F1 phosphorylated on serine 364 is also present at proapoptotic gene promoters during the induction of apoptosis. This indicates that distinct populations of E2F1 are organized in response to DNA damage signaling. Surprisingly, these complexes act in parallel to activate transcription of proapoptotic genes. Our data suggest that DNA damage signals alter pRB and E2F1 to engage them in functions leading to apoptotic induction that are distinct from pRB-E2F regulation in cell cycle control. PMID:22184068

Carnevale, Jasmyne; Palander, Oliva; Seifried, Laurie A.

2012-01-01

146

Evaluation of Emerging Contaminants of Concern at the South District Wastewater Treatment Plant Based on Seasonal Events, Miami-Dade County, Florida, 2004  

USGS Publications Warehouse

The Comprehensive Everglades Restoration Plan has identified highly treated wastewater as a possible water source for the restoration of natural water flows and hydroperiods in selected coastal areas, including the Biscayne Bay coastal wetlands. One potential source of reclaimed wastewater for the Biscayne Bay coastal wetlands is the effluent from the South District Wastewater Treatment Plant in southern Miami-Dade County. The U.S. Geological Survey, in cooperation with the Comprehensive Everglades Restoration Plan Wastewater Reuse Technology Pilot Project Delivery Team, initiated a study to assess the presence of emerging contaminants of concern in the South District Wastewater Treatment Plant influent and effluent using current wastewater-treatment methods. As part of the study, 24-hour composite and discrete samples were collected at six locations (influent at plants 1 and 2, effluent pump, reuse train, chlorine dioxide unit, and ultraviolet pilot unit) at the plant during: (1) a dry-season, low-flow event on March 2-3, 2004, with an average inflow rate of 83.7 million gallons per day; (2) a wet-season, average-flow event on July 20-21, 2004, with an average inflow rate of 89.7 million gallons per day; and (3) high-rate disinfection tests on October 5 and 20, 2004, with average flow rates of 84.1 and 119.6 million gallons per day, respectively. During these four sampling events, 26, 27, 29, and 35 constituents were detected, respectively. The following transformations in concentration were determined in the waste stream: -100 to 180 percent at the effluent pump and -100 to 85 percent at the reuse train on March 2-3, 2004, and -100 to 1,609 percent at the effluent pump and -100 to 832 percent at the reuse train on July 20-21, 2004; -100 to -37 percent at the effluent pump, -100 to -62 percent at the reuse train, -100 to -56 percent at the chlorine dioxide unit, and -100 to -40 percent at the ultraviolet pilot unit on October 5, 2004; and -100 to -4 percent at the effluent pump, -100 to 17 percent at the reuse train, -100 to -40 percent at the chlorine dioxide unit, and -100 to -14 percent at the ultraviolet pilot unit on October 20, 2004. Samples were tested for detection of household and industrial (organic) wastewater compounds, pharmaceutical compounds, antibiotic compounds, and hormones in influent. Two 'known' endocrine disrupting compounds?17 beta-estradiol (E2) and diethoxynonylphenol? and four 'suspected' endocrine-disrupting compounds?1,4-dichlorobenzene, benzophenone, tris(2-chloroethyl) phosphate, and tris(dichloroisopropyl) phosphate?were detected during these sampling events. Phenanthrene and indole showed the greatest concentration ranges and highest concentrations for the organic wastewater compounds. Acetaminophen showed the greatest concentration range and highest concentration, and warfarin showed the smallest concentration range for the pharmaceutical compounds. Sulfamethoxazole (a sulfonamide) showed the greatest concentration range and highest concentration, and sulfathiozole (also a sulfonamide) showed the smallest concentration range for the antibiotic compounds. Two hormones, 17 beta-estradiol (E2) and estrone (E1), were detected in influent. Samples were also tested for detection of organic wastewater compounds, pharmaceutical compounds, antibiotic compounds, and hormones in effluent. Indole showed the greatest concentration range and highest concentration, and triphenyl phosphate showed the smallest concentration range for the organic wastewater compounds. Dehydronifedipine showed the greatest concentration range and highest concentration, and warfarin had the smallest concentration range for the pharmaceutical compounds. Anhydro-erythromycin (a macrolide degradation product) showed the greatest concentration range, and sulfadiazine (a sulfonamide) and tetracycline showed the lowest concentration ranges for the antibiotic compounds. One hormone, 17 beta-estradiol (E2), was det

Lietz, Arthur C.; Meyer, Michael T.

2006-01-01

147

Estrogen enhances susceptibility to experimental autoimmune myasthenia gravis by promoting type 1-polarized immune responses.  

PubMed

Myasthenia gravis (MG) is an organ-specific autoimmune disease caused in most cases by autoantibodies against the nicotinic acetylcholine receptor (AChR). It is now well documented that many autoimmune diseases, including MG, are more prevalent in women than in men, and that fluctuations in disease severity occur during pregnancy. These observations raise the question of the potential role of sex hormones, such as estrogens, as mediators of sex differences in autoimmunity. In the present study, we have analyzed the effect of 17beta-estradiol (E2) on the pathogenesis of experimental autoimmune myasthenia gravis (EAMG), an animal model of MG. We show that treatment with E2 before Ag priming is necessary and sufficient to promote AChR-specific Th1 cell expansion in vivo. This time-limited exposure to E2 enhances the production of anti-AChR IgG2a(b) (specific for b allotype; e.g., B6) and IgG2b, but not IgG1, and significantly increases the severity of EAMG in mice. Interestingly, the E2-mediated augmentation in AChR-specific Th1 response correlates with an enhanced production of IL-12 by splenic APCs through the recruitment of CD8alpha(+) dendritic cells. These data provide the first evidence that estrogen enhances EAMG, and sheds some light on the role of sex hormones in immune responses and susceptibility to autoimmune disease in women. PMID:16210608

Delpy, Laurent; Douin-Echinard, Victorine; Garidou, Lucile; Bruand, Corinne; Saoudi, Abdelhadi; Guéry, Jean-Charles

2005-10-15

148

Modulation of the cytosolic androgen receptor in striated muscle by sex steroids  

NASA Technical Reports Server (NTRS)

The effects of orchiectomy (GDX) and of subsequent administration of testosterone propionate (TP) or 17(beta)-estradiol (E2) on the maximum binding (Bmax) and apparent Kd of the cytosolic androgen receptor in levator ani (LA) and skeletal muscles of adult male Sprague-Dawley rats are investigated experimentally. The results are presented in graphs and discussed. In LA, BMAX is found to rise from a control level of 2.5 fmol/mg protein to 280, 600, 478, and 133 percent of control at 12 h, 14 d, 30 d, and 44 d after GDX, respectively, while Kd increased only insignificantly (from 680 to 960 fM); Bmax is held at control levels for 6 h by cycloheximide given at GDX, is unaffected by TP given at 30 d, and is further increased (by 480 percent at 44 d) by administration of E2 at 30 d. Bmax in skeletal muscles is found to increase to 139, 212, 220, and 158 percent of control at 12 h, 14 d, 30 d, and 44 d, respectively; Bmax is returned to control at 44 d by TP at 30 d but is not affected by E2. The effect of E2 in LA is attributed to either induction of the cytosolic receptor or a decreased rate of receptor degradation.

Rance, N. E.; Max, S. R.

1984-01-01

149

The apolipoprotein E ?2 allele and decline in episodic memory  

PubMed Central

Objectives: The apolipoprotein E (apoE) ?4 allele is related to decline in multiple cognitive domains, especially episodic memory, but the effect of the ?2 allele on change in different forms of cognitive function has been difficult to establish. Methods: Participants are from the Religious Orders Study. At baseline, they were at least 65 years old and free of clinical evidence of dementia. For up to eight years, they underwent annual clinical evaluations that included detailed cognitive function assessment from which previously established summary measures of episodic memory, semantic memory, working memory, perceptual speed, and visuospatial ability were derived. Growth curve models were used to assess change in each measure and its relation to apoE genotype, controlling for age, sex, education, and baseline level of cognition. Follow up data were available in 669 persons (98% of those eligible). We treated those with the ?3/3 genotype as the reference group (n=425), which was contrasted with ?2 (?2/2, ?2/3; n=86), and ?4 (?3/4, ?4/4; n=158) subgroups. Results: Rate of episodic memory change in the three subgroups significantly differed, with an average annual increase of 0.016 units in the ?2 subgroup and annual decreases of 0.022 units in those with ?3/3 and of 0.073 units in the ?4 subgroup. The ?2 subgroup did not differ from those with ?3/3 in rate of decline in other cognitive systems. The ?4 subgroup declined more rapidly than those with ?3/3 in semantic memory and perceptual speed but not in working memory or visuospatial ability. Conclusion: Possession of one or more apoE ?2 alleles is associated with reduced decline in episodic memory in older persons. PMID:12438469

Wilson, R; Bienias, J; Berry-Kravis, E; Evans, D; Bennett, D

2002-01-01

150

Functional Replacement of the Mouse E2A Gene with a Human HEB cDNA  

PubMed Central

The mammalian E2A, HEB, and E2-2 genes encode a unique class of basic helix-loop-helix (bHLH) transcription factors that are evolutionarily conserved and essential for embryonic and postnatal development. While the structural and functional similarities among the gene products are well demonstrated, it is not clear why deletion of E2A, but not HEB or E2-2, leads to a complete arrest in B-lymphocyte development. To understand the molecular basis of the functional specificity between E2A and HEB/E2-2 in mammalian development, we generated and tested a panel of E2A knockin mutations including subtle mutations in the E12 and E47 exons and substitution of both E12 and E47 exons with a human HEB cDNA. We find that the alternatively spliced E12 and E47 bHLH proteins of the E2A gene play similar and additive roles in supporting B lymphopoiesis. Further, we find that HEB driven by the endogenous E2A promoter can functionally replace E2A in supporting B-cell commitment and differentiation toward completion. Finally, the postnatal lethality associated with E2A disruption is fully rescued by the addition of HEB. This study suggests that the functional divergence among E12, E47, and HEB in different cell types is partially defined by the context of gene expression. PMID:9584174

Zhuang, Yuan; Barndt, Robert J.; Pan, Lihua; Kelley, Robert; Dai, Meifang

1998-01-01

151

Immunogenicity of recombinant BCGs expressing predicted antigenic epitopes of bovine viral diarrhea virus E2 gene.  

PubMed

To develop a vaccine to prevent diseases caused by Mycobacterium tuberculosis and bovine viral diarrhea virus (BVDV) simultaneously, recombinant Bacillus Calmette-Guerin (rBCG) vaccines expressing different regions of the BVDV E2 gene were constructed. Using DNASTAR 6.0 software, potential antigenic epitopes were predicted, and six regions were chosen to generate recombinant plasmids with the pMV361 vector (pMV361-E2-1, pMV361-E2-2, pMV361-E2-3, pMV361-E2-4, pMV361-E2-5 and pMV361-E2-6, respectively). The recombinant plasmids were transformed into BCG, and protein expression was thermally induced at 45?°C. Mice were immunized with 5 × 10(6) CFU/200 µL of each rBCG strain. Compared with other groups, BVDV E2 specific antibody titers were higher in mice immunized with rBCG-E2-6. Ratios and numbers of CD4+, CD8+ and IL-12 expressing spleen lymphocytes of the rBCG-E2-6 group also were higher than those of other groups. Thus, the rBCG-E2-6 vaccine showed the highest immunogenicity of all groups based on the humoral and cellular responses to vaccination. PMID:25135492

Liu, Dongxu; Lu, Huijun; Shi, Kun; Su, Fengyan; Li, Jianming; Du, Rui

2014-10-01

152

Inhibition of mesangial cell proliferation by E2F decoy oligodeoxynucleotide in vitro and in vivo.  

PubMed Central

The transcription factor E2F coordinately activates several cell cycle-regulatory genes. We attempted to inhibit the proliferation of mesangial cells in vitro and in vivo by inhibiting E2F activity using a 25-bp decoy oligodeoxynucleotide that contained consensus E2F binding site sequence (E2F-decoy) as a competitive inhibitor. The decoy's effect on human mesangial cell proliferation was evaluated by [3H]thymidine incorporation. The E2F decoy inhibited proliferation in a concentration-dependent manner, whereas a mismatch control oligodeoxynucleotide had little effect. Electrophoretic mobility shift assays demonstrated that the decoy's inhibitory effect was due to the binding of the decoy oligodeoxynucleotide to E2F. The effect of the E2F decoy was then tested in a rat anti-Thy 1.1 glomerulonephritis model. The E2F decoy oligodeoxynucleotide was introduced into the left kidney 36 h after the induction of glomerulonephritis. The administration of E2F decoy suppressed the proliferation of mesangial cells by 71%. Furthermore, treatment with the E2F decoy inhibited the glomerular expression of proliferating cell nuclear antigen at the protein level as well as the mRNA level. These findings indicate that decoy oligonucleotides can suppress the activity of the transcription factor E2F, and may thus have a potential in treating glomerulonephritis. PMID:9616230

Maeshima, Y; Kashihara, N; Yasuda, T; Sugiyama, H; Sekikawa, T; Okamoto, K; Kanao, K; Watanabe, Y; Kanwar, Y S; Makino, H

1998-01-01

153

Regulation of human genome expression and RNA splicing by human papillomavirus 16 E2 protein.  

PubMed

Human papillomavirus 16 (HPV16) is causative in human cancer. The E2 protein regulates transcription from and replication of the viral genome; the role of E2 in regulating the host genome has been less well studied. We have expressed HPV16 E2 (E2) stably in U2OS cells; these cells tolerate E2 expression well and gene expression analysis identified 74 genes showing differential expression specific to E2. Analysis of published gene expression data sets during cervical cancer progression identified 20 of the genes as being altered in a similar direction as the E2 specific genes. In addition, E2 altered the splicing of many genes implicated in cancer and cell motility. The E2 expressing cells showed no alteration in cell growth but were altered in cell motility, consistent with the E2 induced altered splicing predicted to affect this cellular function. The results present a model system for investigating E2 regulation of the host genome. PMID:25129434

Gauson, Elaine J; Windle, Brad; Donaldson, Mary M; Caffarel, Maria M; Dornan, Edward S; Coleman, Nicholas; Herzyk, Pawel; Henderson, Scott C; Wang, Xu; Morgan, Iain M

2014-11-01

154

EGFR Signaling Inhibits E2F1-Induced Apoptosis in Vivo: Implications for Cancer Therapy  

NSDL National Science Digital Library

The retinoblastoma tumor suppressor (RB) restricts cell proliferation by regulating members of the E2F family of transcription factors. In human tumors RB is often inactivated, resulting in aberrant E2F-dependent transcription and uncontrolled proliferation. One of the E2F proteins, E2F1, can also induce apoptosis. The extent of E2F1-induced apoptosis is known to be tissue- and cell-specific, but until now, it has been unclear what variables determine cellular sensitivity to E2F1-induced apoptosis in vivo. A recent study reveals epidermal growth factor receptor (EGFR) signaling to be one such variable, as EGFR signaling cooperates with RB in inhibiting E2F1-induced apoptosis. This finding raises the possibility that therapeutic manipulation of EGFR signaling may specifically trigger the death of cancer cells with inactive RB, thereby enabling "targeted" cancer treatments.

Doron Ginsberg (Bar Ilan University; Mina and Everard Goodman Faculty of Life Science REV)

2007-01-30

155

APC/CCdc20 targets E2F1 for degradation in prometaphase  

PubMed Central

The mechanisms that control E2F-1 activity are complex. We previously showed that Chk1 and Chk2 are required for E2F1 stabilization and p73 target gene induction following DNA damage. To gain further insight into the processes regulating E2F1 protein stability, we focused our investigation on the mechanisms responsible for regulating E2F1 turnover. Here we show that E2F1 is a substrate of the anaphase-promoting complex or cyclosome (APC/C), a ubiquitin ligase that plays an important role in cell cycle progression. Ectopic expression of the APC/C activators Cdh1 and Cdc20 reduced the levels of co-expressed E2F-1 protein. Co-expression of DP1 with E2F1 blocked APC/C-induced E2F1 degradation, suggesting that the E2F1/DP1 heterodimer is protected from APC/C regulation. Following Cdc20 knockdown, E2F1 levels increased and remained stable in extracts over a time course, indicating that APC/CCdc20 is a primary regulator of E2F1 stability in vivo. Moreover, cell synchronization experiments showed that siRNA directed against Cdc20 induced an accumulation of E2F1 protein in prometaphase cells. These data suggest that APC/CCdc20 specifically targets E2F1 for degradation in early mitosis and reveal a novel mechanism for limiting free E2F1 levels in cells, failure of which may compromise cell survival and/or homeostasis. PMID:20948288

Peart, Melissa J; Poyurovsky, Masha V; Kass, Elizabeth M; Urist, Marshall; Verschuren, Emmy W; Summers, Matthew K; Jackson, Peter K

2010-01-01

156

Loop 7 of E2 Enzymes: An Ancestral Conserved Functional Motif Involved in the E2-Mediated Steps of the Ubiquitination Cascade  

PubMed Central

The ubiquitin (Ub) system controls almost every aspect of eukaryotic cell biology. Protein ubiquitination depends on the sequential action of three classes of enzymes (E1, E2 and E3). E2 Ub-conjugating enzymes have a central role in the ubiquitination pathway, interacting with both E1 and E3, and influencing the ultimate fate of the substrates. Several E2s are characterized by an extended acidic insertion in loop 7 (L7), which if mutated is known to impair the proper E2-related functions. In the present contribution, we show that acidic loop is a conserved ancestral motif in E2s, relying on the presence of alternate hydrophobic and acidic residues. Moreover, the dynamic properties of a subset of family 3 E2s, as well as their binary and ternary complexes with Ub and the cognate E3, have been investigated. Here we provide a model of L7 role in the different steps of the ubiquitination cascade of family 3 E2s. The L7 hydrophobic residues turned out to be the main determinant for the stabilization of the E2 inactive conformations by a tight network of interactions in the catalytic cleft. Moreover, phosphorylation is known from previous studies to promote E2 competent conformations for Ub charging, inducing electrostatic repulsion and acting on the L7 acidic residues. Here we show that these active conformations are stabilized by a network of hydrophobic interactions between L7 and L4, the latter being a conserved interface for E3-recruitment in several E2s. In the successive steps, L7 conserved acidic residues also provide an interaction interface for both Ub and the Rbx1 RING subdomain of the cognate E3. Our data therefore suggest a crucial role for L7 of family 3 E2s in all the E2-mediated steps of the ubiquitination cascade. Its different functions are exploited thank to its conserved hydrophobic and acidic residues in a finely orchestrate mechanism. PMID:22815819

Papaleo, Elena; Casiraghi, Nicola; Arrigoni, Alberto; Vanoni, Marco; Coccetti, Paola; De Gioia, Luca

2012-01-01

157

Regulation of E2F1-induced apoptosis by poly(ADP-ribosyl)ation.  

PubMed

The transcription factor adenovirus E2 promoter-binding factor (E2F)-1 normally enhances cell-cycle progression, but it also induces apoptosis under certain conditions, including DNA damage and serum deprivation. Although DNA damage facilitates the phosphorylation and stabilization of E2F1 to trigger apoptosis, how serum starvation renders cells vulnerable to E2F1-induced apoptosis remains unclear. Because poly(ADP-ribose) polymerase 1 (PARP1), a nuclear enzyme essential for genomic stability and chromatin remodeling, interacts directly with E2F1, we investigated the effects of PARP1 on E2F1-mediated functions in the presence and absence of serum. PARP1 attenuation, which increased E2F1 transactivation, induced G2/M cell-cycle arrest under normal growth conditions, but enhanced E2F1-induced apoptosis in serum-starved cells. Interestingly, basal PARP1 activity was sufficient to modify E2F1 by poly(ADP-ribosyl)ation, which stabilized the interaction between E2F1 and the BIN1 tumor suppressor in the nucleus. Accordingly, BIN1 acted as an RB1-independent E2F1 corepressor. Because E2F1 directly activates the BIN1 gene promoter, BIN1 curbed E2F1 activity through a negative-feedback mechanism. Conversely, when the BIN1-E2F1 interaction was abolished by PARP1 suppression, E2F1 continuously increased BIN1 levels. This is functionally germane, as PARP1-depletion-associated G2/M arrest was reversed by the transfection of BIN1 siRNA. Moreover, PARP-inhibitor-associated anti-transformation activity was compromised by the coexpression of dominant-negative BIN1. Because serum starvation massively reduced the E2F1 poly(ADP-ribosyl)ation, we conclude that the release of BIN1 from hypo-poly(ADP-ribosyl)ated E2F1 is a mechanism by which serum starvation promotes E2F1-induced apoptosis. PMID:25257171

Kumari, A; Iwasaki, T; Pyndiah, S; Cassimere, E K; Palani, C D; Sakamuro, D

2015-02-01

158

Amplification of the E2F1 transcription factor gene in the HEL erythroleukemia cell line  

SciTech Connect

The E2F transcription factor plays an important regulatory role in cell proliferation, mediating the expression of genes whose products are essential for inducing resting cells to enter the cell cycle and synthesize DNA. To investigate the possible involvement of E2F in hematopoietic malignancies, we isolated genomic clones encompassing the human E2F1 gene. We then used fluorescence in situ hybridization to localize E2F1 to human chromosome 20q11, telomeric to the p107 locus, a gene whose product is related to the retinoblastoma gene product (pRb). This finding contrasts with the 1p36 and 6q22 chromosomal locations previously assigned E2F2 and E2F3, two additional members of the E2F family. Although deletions or structural rearrangements of E2F1 were not detected in 14 primary acute leukemia or myelodysplasia samples with structural abnormalities of chromosome 20q11, the gene was amplified and overexpressed in HEL erythroleukemia cells and translocated to other chromosomes in several established human leukemia cell lines. This study provides the first evidence of gene amplification involving a member of the E2F family of transcription factors. We propose that E2F1 overexpression in erythroid progenitors may stimulate abnormal cell proliferation by overriding negative regulatory signals mediated by tumor suppressor proteins such as pRb. 76 refs., 5 figs., 2 tabs.

Saito, M.; Valentine, M.B.; Look, A.T. [St. Jude Children`s Research Hosptial, Memphis, TN (United States)] [and others] [St. Jude Children`s Research Hosptial, Memphis, TN (United States); and others

1995-01-01

159

Transcriptional regulation of human RANK ligand gene expression by E2F1  

SciTech Connect

Receptor activator of nuclear factor kappa B ligand (RANKL) is a critical osteoclastogenic factor involved in the regulation of bone resorption, immune function, the development of mammary gland and cardiovascular system. To understand the transcriptional regulation of RANKL, we amplified and characterized a 1890 bp 5'-flanking sequence of human RANKL gene (-1782 bp to +108 bp relative to the transcription start site). Using a series of deletion mutations of the 1890 bp RANKL promoter, we identified a 72 bp region (-172 to -100 bp) mediating RANKL basal transcriptional activity. Sequence analysis revealed a putative E2F binding site within this 72 bp region in the human RANKL promoter. Overexpression of E2F1 increased RANKL promoter activity, while down-regulation of E2F1 expression by small interfering RNA decreased RANKL promoter activity. RT-PCR and enzyme linked immunosorbent assays (ELISA) further demonstrated that E2F1 induced the expression of RANKL. Electrophoretic gel mobility shift assays (EMSA) and antibody competition assays confirmed that E2F1 proteins bind to the consensus E2F binding site in the RANKL promoter. Mutation of the E2F consensus binding site in the RANKL promoter profoundly reduced the basal promoter activity and abolished the transcriptional modulation of RANKL by E2F1. These results suggest that E2F1 plays an important role in regulating RANKL transcription through binding to the E2F consensus binding site.

Hu Yan [Department of Stress Biology, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Sun Meng [Department of Urology and Cancer Center, University of California at Davis, School of Medicine, 4860 Y Street, Suite 3500, Sacramento, CA 95817 (United States); Graduate Program of Pharmacology and Toxicology, University of California at Davis, Sacramento, CA 95817 (United States); Nadiminty, Nagalakshmi; Lou Wei [Department of Urology and Cancer Center, University of California at Davis, School of Medicine, 4860 Y Street, Suite 3500, Sacramento, CA 95817 (United States); Pinder, Elaine [Department of Urology and Cancer Center, University of California at Davis, School of Medicine, 4860 Y Street, Suite 3500, Sacramento, CA 95817 (United States); Graduate Program of Pharmacology and Toxicology, University of California at Davis, Sacramento, CA 95817 (United States); Gao, Allen C. [Department of Urology and Cancer Center, University of California at Davis, School of Medicine, 4860 Y Street, Suite 3500, Sacramento, CA 95817 (United States); Graduate Program of Pharmacology and Toxicology, University of California at Davis, Sacramento, CA 95817 (United States)], E-mail: acgao@ucdavis.edu

2008-06-06

160

Skp2 suppresses apoptosis in Rb1-deficient tumours by limiting E2F1 activity.  

PubMed

One mechanism of tumour suppression by pRb is repressing E2F1. Hence, E2f1 deletion diminishes tumorigenesis following Rb1 loss. However, E2F1 promotes both proliferation and apoptosis. It therefore remains unclear how de-repressed E2F1 promotes tumorigenesis. Another mechanism of pRb function is repressing Skp2 to elevate p27 to arrest proliferation. However, Skp2 deletion induced apoptosis, not proliferation arrest, in Rb1-deficient pituitary tumorigenesis. Here we show that Rb1 deletion induces higher expression of E2F1 target genes in the absence of Skp2. E2F1 binds less cyclin A but more target promoters when Rb1 is deleted with Skp2 knockout or p27T187A knockin, suggesting that stabilized p27 prevents cyclin A from binding and inhibiting E2F1. In Rb1-deficient pituitary tumorigenesis, Skp2 deletion or p27T187A mutation converts E2F1's role from proliferative to apoptotic. These findings delineate a pRb-Skp2-p27-cyclin A-E2F1 pathway that determines whether E2F1 is proliferative or apoptotic in Rb1-deficient tumorigenesis. PMID:24632684

Lu, Zhonglei; Bauzon, Frederick; Fu, Hao; Cui, Jinhua; Zhao, Hongling; Nakayama, Keiko; Nakayama, Keiich I; Zhu, Liang

2014-01-01

161

Differential involvement of E2A-corepressor interactions in distinct leukemogenic pathways.  

PubMed

E2A is a member of the E-protein family of transcription factors. Previous studies have reported context-dependent regulation of E2A-dependent transcription. For example, whereas the E2A portion of the E2A-Pbx1 leukemia fusion protein mediates robust transcriptional activation in t(1;19) acute lymphoblastic leukemia, the transcriptional activity of wild-type E2A is silenced by high levels of corepressors, such as the AML1-ETO fusion protein in t(8;21) acute myeloid leukemia and ETO-2 in hematopoietic cells. Here, we show that, unlike the HEB E-protein, the activation domain 1 (AD1) of E2A has specifically reduced corepressor interaction due to E2A-specific amino acid changes in the p300/CBP and ETO target motif. Replacing E2A-AD1 with HEB-AD1 abolished the ability of E2A-Pbx1 to activate target genes and to induce cell transformation. On the other hand, the weak E2A-AD1-corepressor interaction imposes a critical importance on another ETO-interacting domain, downstream ETO-interacting sequence (DES), for corepressor-mediated repression. Deletion of DES abrogates silencing of E2A activity by AML1-ETO in t(8;21) leukemia cells or by ETO-2 in normal hematopoietic cells. Our results reveal an E2A-specific mechanism important for its context-dependent activation and repression function, and provide the first evidence for the differential involvement of E2A-corepressor interactions in distinct leukemogenic pathways. PMID:24064250

Gow, Chien-Hung; Guo, Chun; Wang, David; Hu, Qiande; Zhang, Jinsong

2014-01-01

162

Sertoli-Leydig cell tumors: hormonal profile after dynamic test with GnRH analogue: triptorelin represents a useful tool to evaluate tumoral hyperandrogenism.  

PubMed

Abstract We report the case of a 15-year-old woman with signs of hyperandrogenism affected by a Sertoli-Leydig cell tumor (SLCT). In our patient, blood analysis showed a high testosterone (T) level (T: 8.53?nmol/L; nv?17-beta estradiol (E2) and T, from 2 to 18 times higher than healthy women. When we compared our patient with healthy men, we differently observed a comparable response of T. The response of our patient was also comparable with that observed in the PCOS group for E2. During the post-surgical follow up, the GnRH-analogue test of our patient showed a response of OHP, T, and E2 comparable with that of the PCOS group. The GnRH-analogue test is a useful tool to characterize steroidogenesis in SLCT. PMID:25299229

Turra, J; Granzotto, M; Gallea, M; Faggian, D; Conte, L; Litta, P; Vettor, R; Mioni, R

2015-01-01

163

Lack of activity of cadmium in in vitro estrogenicity assays.  

PubMed

Prompted by reports about strong estrogenic effects of cadmium, attempts were made to reproduce these observations using the yeast estrogen screen (YES) and the E-Screen assays. For the first time, possible activation of the Src/MAPK pathway was also investigated. In the YES, only a slight activation (10% of a maximal effect) of the estrogen receptor alpha (ERalpha) was observed at cadmium concentrations between 5 x 10(-7) M and 5 x 10(-6) M. In the E-Screen assay, carried out by two laboratories, the heavy metal was without observable cell proliferative effects when tested in the range between 6 x 10(-11) M and 1 x 10(-5) M. However, in both assays, cadmium led to a reduction of the effects of 17beta-estradiol (E2). Treatment of MCF-7 human breast cancer cells with 1 x 10(-7) M cadmium failed to induce phosphorylation of Src and the MAP kinases Erk1 and Erk2-effects shown to occur with E2 and epidermal growth factor (EGF). In summary, we were unable to confirm the strong estrogenicity of cadmium reported recently by a number of laboratories. This apparent absence of effects in our hands is not due to a lack of uptake of the metal or to effective protection against cadmium by high levels of glutathione or metallothionein, since toxicity and an antagonism of E2 responses were observed both in the YES and the E-Screen. PMID:16716372

Silva, Elisabete; Lopez-Espinosa, Maria José; Molina-Molina, José-Manuel; Fernández, Marieta; Olea, Nicolas; Kortenkamp, Andreas

2006-10-01

164

Effects of postoperative adjuvant chemotherapy and radiotherapy on ovarian function in women undergoing treatment for soft tissue sarcoma  

SciTech Connect

Ovarian function was evaluated in 11 women 16 to 43 years of age at treatment who received doxorubicin, cyclophosphamide, and high doses of methotrexate with or without radiotherapy in adjuvant therapy of soft tissue sarcoma. Five women (16-33 yr old) who received chemotherapy alone or combined with radiotherapy only at sites distant from the ovaries (chest wall, thigh, and leg) had minimal menstrual irregularities or temporary cessation of menses during therapy; cyclic menses returned promptly after therapy. Gonadotropin levels (expressed as means +/- SD (follicle-stimulating hormone (FSH), 10 +/- 5 mlU/ml; luteinizing hormone (LH), 10 +/- 4 mlU/ml) and 17 beta-estradiol (E2) levels (means +/- SD, 208 +/- 147 pg/ml) were normal. By contrast, 4 older women (ages 36-43 yr) who received similar treatment developed persistent amenorrhea with postmenopausal levels of gonadotropin (FSH, 108 +/- 29 mlU/ml; LH, 72 +/- 19 mlU/ml) and E2 (19 +/- 8 pg/ml). Two additional women (ages 21 and 39 yr) who received radiation (7,000 rad) to the pelvis plus chemotherapy developed prompt cessation of menses and became functional castrates (FSH, 77 and 80 mlU/ml; LH, 40 and 58 mlU/ml; E2, 10 and 19 pg/ml). However, this result would be expected from the radiation dose alone. The data demonstrated that ovarian dysfunction may follow the use of doxorubicin, cyclophosphamide, and high doses of methotrexate and that the injury is age related.

Shamberger, R.C.; Sherins, R.J.; Ziegler, J.L.; Glatstein, E.; Rosenberg, S.A.

1981-12-01

165

Effect of sex hormones on human T cell activation by concanavalin A.  

PubMed

The effect of sex hormones on concanavalin A (Con A)-activated human T cells was studied. We show that neither 17 beta-estradiol (E2) nor progesterone, in concentrations of up to 10(-6) M, alters the proliferative response of peripheral-blood mononuclear cells (PBMC) of healthy postmenopausal women. Furthermore, the hormones had no effect on the composition of T cell populations and on the expression of activation markers. We extended our study to a unique T cell population that is characterized by the ability to form rosettes with human erythrocytes, following Con A activation (designated autorosette-forming cells; ARFC) and known to manifest suppressive activity. Indeed, the in vitro addition of E2 (neither progesterone nor testosterone) to Con A-stimulated PBMC brought an about 2- to 4-fold increase in the frequency of ARFC. Tamoxifen, an antiestrogen drug, reduced the frequency of estrogen-stimulated ARFC to the original low level. Furthermore, the inhibitory effect of growth medium from ARFC cultures originally stimulated with Con A + E2 was found to be higher than that of ARFC cultures originally stimulated with Con A alone. PMID:2057020

Yron, I; Langer, A; Weinstein, T; Sahar, E; Lidor, Y; Pardo, Y; Katz, I; Shohat, L; Kalechman, Y; Ovadia, J

1991-01-01

166

Effect of polar day on plasma profiles of melatonin, testosterone, and estradiol in high-Arctic Lapland Longspurs.  

PubMed

In polar habitats, continuous daylight (polar day) can prevail for many weeks or months around the summer solstice. In the laboratory, continuous light conditions impair or disrupt circadian rhythms in many animals. To determine whether circadian rhythms are disrupted under natural polar day conditions in a species that is only a summer resident in polar regions we analyzed diel rhythms in plasma concentrations of melatonin, testosterone (T), and 17-beta estradiol (E(2)) during the summer solstice in Arctic-breeding Lapland Longspurs (Calcarius lapponicus). We compared these profiles to those of conspecifics housed in outdoor aviaries at a mid-latitude site in Seattle, Washington, during spring, summer, fall, and winter. Under polar day conditions plasma melatonin concentrations of Lapland Longspurs were strongly suppressed, but still showed a significant diel rhythm. Likewise, plasma T in males, and E(2) in females, showed significant diel changes in Arctic birds. Lapland Longspurs housed at mid-latitude in Seattle showed high-amplitude melatonin cycles at all times of the year, and the duration of the nightly melatonin secretion was positively correlated with the duration of the dark phase. We found no diel changes in plasma T in Seattle males in May, but Seattle females showed significant day/night differences in plasma E(2) in May. The data suggest that even under polar day conditions diel rhythms can persist. The maintenance of hormone rhythms could provide a physiological basis to reports of rhythmic behavior in many birds during the Arctic summer. PMID:11944971

Hau, Michaela; Romero, L Michael; Brawn, Jeff D; Van't Hof, Thomas J

2002-03-01

167

Estrogen receptor alpha is a major contributor to estrogen-mediated fetal testis dysgenesis and cryptorchidism.  

PubMed

Failure of the testes to descend into the scrotum (cryptorchidism) is one of the most common birth defects in humans. In utero exposure to estrogens, such as 17beta-estradiol (E2) or the synthetic estrogen diethylstilbestrol (DES), down-regulates insulin-like 3 (Insl3) expression in embryonic Leydig cells, which in turn results in cryptorchidism in mice. To identify the molecular mechanism whereby xenoestrogens block Insl3 gene transcription, we performed a microarray analysis of wild-type or estrogen receptor (ER) alpha-mutant testes exposed in utero to pharmacological doses of E2 or DES. Six and 31 genes were respectively down-regulated and up-regulated by estrogen exposure (> or =4-fold). All six genes down-regulated by estrogen exposure, including Insl3 and the steroidogenic genes steroidogenic acute regulatory protein and cytochrome P450 17alpha-hydroxylase/17,20-lyase, were done so by an ERalpha-dependent mechanism. In contrast, up-regulation was mediated either by ERalpha for 12 genes or by an independent mechanism for the 19 remaining genes. Finally, we show that Insl3 gene expression and testicular descent were not affected by in utero exposure to E2 or DES in ERalpha mutant mice, whereas absence of ERbeta did not influence the effect of these estrogens. Collectively, these data demonstrate that xenoestrogens inhibit the endocrine functions of fetal Leydig cells through an ERalpha-dependent mechanism. PMID:17673513

Cederroth, Christopher R; Schaad, Olivier; Descombes, Patrick; Chambon, Pierre; Vassalli, Jean-Dominique; Nef, Serge

2007-11-01

168

Metabolism of testosterone by human granulosa cells in culture: influence of follicle-stimulating hormone and luteinizing hormone  

SciTech Connect

Human granulosa cells were isolated from follicles (8 to 15 mm) and cultivated for 24 hours in the presence or absence of follicle-stimulating hormone (NIH-FSH-HS-1, 1 microgram/ml) and luteinizing hormone (NIAMDD-hLH-1, 1 microgram/ml). Testosterone -4-14C was added subsequently to all cultures for 4-, 6-, and 24-hour periods. Of the seven metabolites of testosterone studied, 17 beta-estradiol (E2) and estrone (E1) were the major products. In all patients, levels of E2 were three to ten times higher than those of E1. Production of E2, but not E1, was stimulated by either follicle-stimulating hormone (FSH) or luteinizing hormone (LH). The cells of the largest follicle (15 mm) showed greater response to LH than to FSH. Production of the other C19 and C18 metabolites was very low or negligible. These results further suggest that FSH regulates the aromatization of testosterone in human granulosa cells, and that LH may have the same effect on the matured follicle during the preovulatory period.

Moon, Y.S.; Duleba, A.; Leung, P.C.; Gomel, V.

1982-03-15

169

A novel E2F binding protein with Myc-type HLH motif stimulates E2F-dependent transcription by forming a heterodimer  

Microsoft Academic Search

The human embryonal carcinoma cells NEC14 can be induced to differentiate morphologically by the addition of 10?2 M N, N?-hexamethylene-bis-acetamide and cease to grow in several days. Transcription factors of the E2F\\/DP family have been shown to be closely related to the regulation of cell proliferation. To analyse cellular proteins which interact with E2F in NEC14 cells, cDNA clones encoding

Mitsuhiro Suzuki; Satoshi Okuyama; Satoru Okamoto; Kenna Shirasuna; Takuma Nakajima; Takahisa Hachiya; Hiroshi Nojima; Souei Sekiya; Kinichiro Oda

1998-01-01

170

Ratio B(E2, 4\\rightarrow2 )/B(E2, 2\\rightarrow 0) in Even-Even Nuclei:Apparent Anomalous Behavior of the Chromium Isotopes  

E-print Network

We consider the ratio RE4 = B(E2,4\\rightarrow2 )/B(E2,2\\rightarrow 0) for the lowest 2^{+} and 4^{+} states in even-even nuclei. In the rotatonal and vibrational models and the shell model calculations here considered, RE4 is greater than one, however empirically, using adopted values from NNDC for ^{48}Cr and ^{50} Cr this ratio is less than one.

Hertz-Kintish, Daniel

2014-01-01

171

Ratio B(E2, 4\\rightarrow2)/B(E2, 2\\rightarrow 0) in Even-Even Nuclei:Apparent Anomalous Behavior of the Chromium Isotopes  

E-print Network

We consider the ratio RE4 = B(E2,4\\rightarrow2)/B(E2,2\\rightarrow 0) for the lowest 2^{+} and 4^{+} states in even-even nuclei. In the rotatonal and vibrational models and the shell model calculations here considered, RE4 is greater than one, however empirically, using adopted values from NNDC for ^{48}Cr and ^{50} Cr this ratio is less than one.

Daniel Hertz-Kintish; Larry Zamick

2014-08-01

172

Interaction of the 72-kilodalton human cytomegalovirus IE1 gene product with E2F1 coincides with E2F-dependent activation of dihydrofolate reductase transcription.  

PubMed Central

Three polypeptides are produced from the major immediate-early (IE) region of human cytomegalovirus by alternative splicing. The IE gene products regulate subsequent viral and cellular gene expression. We previously reported that cotransfection of a genomic clone of the major IE region stimulated transient expression of chloramphenicol acetyltransferase driven by the dihydrofolate reductase (DHFR) promoter and that an intact E2F site was required for the trans activation (M. Wade, T. F. Kowalik, M. Mudryj, E.-S. Huang, and J. C. Azizkhan, Mol. Cell. Biol. 12:4364-4374, 1992). With the availability of cDNA clones for the individual major IE proteins, we sought to determine which of these proteins exerted this effect and whether the IE protein(s) interacted with E2F. In this study, we use cotransfection to demonstrate that the 55- and 86-kDa major IE proteins from the IE2 region can each moderately trans activate the DHFR promoter and that the 72-kDa IE1 protein stimulates DHFR transcription to a much higher level. Furthermore, trans activation through the 72-kDa IE1 protein is in part E2F dependent, while activation by the 55- and 86-kDa IE proteins is E2F independent. We also demonstrate by in vitro pull-down assays that the 72-kDa IE1 protein can specifically interact with the DNA binding domain of E2F1 (amino acids 88 to 191) in the presence of nuclear extract. Moreover, antibodies to either E2F1 or IE72 will immunoprecipitate both E2F and IE72 from cells that stably express IE72, and antibody to E2F1 will immunoprecipitate IE72 from normal human fibroblast cells infected with human cytomegalovirus. PMID:7494286

Margolis, M J; Pajovic, S; Wong, E L; Wade, M; Jupp, R; Nelson, J A; Azizkhan, J C

1995-01-01

173

Inhibition of E2F-mediated transcription by p202.  

PubMed Central

Many of the antimicrobial, immunomodulatory and cell growth inhibitory activities of the interferons are mediated by interferon-inducible proteins. Earlier we characterized an interferon-inducible murine protein, p202, whose expression in transfected cells inhibits cell proliferation and which can form a complex with retinoblastoma protein (pRb). Here we report that in transfected cells expression of p202 inhibits E2F-stimulated transcription of a reporter gene and of endogenous genes. Inhibition of the transcriptional activity of E2F by p202 does not depend on fully functional pRb and is correlated with inhibition of the sequence-specific DNA binding of E2F. p202 interacts with the transcription factor E2F (E2F-1/DP-1) in vitro and in vivo. Inhibition of E2F activity by p202 may contribute to growth inhibition by the interferons. Images PMID:8896460

Choubey, D; Li, S J; Datta, B; Gutterman, J U; Lengyel, P

1996-01-01

174

The transcriptional coregulator RIP140 represses E2F1 activity and discriminates breast cancer subtypes  

PubMed Central

Purpose Receptor interacting protein of 140 kDa (RIP140) is a transcriptional cofactor for nuclear receptors involved in reproduction and energy homeostasis. Our aim was to investigate its role in the regulation of E2F1 activity and target genes, both in breast cancer cell lines and in tumor biopsies. Experimental Design GST pull-down assays, coimmunoprecipitation experiments and ChIP analysis were used to evidence interaction between RIP140 and E2F1. The effects of RIP140 expression on E2F1 activity were determined using transient transfection and quantification of E2F-target mRNAs by RT-QPCR. The effect on cell cycle was assessed by FACS analysis on cells overexpressing GFP-tagged RIP140. A tumor microarray data set was used to investigate the expression of RIP140 and E2F1-target genes in 170 breast cancer patients. Results We first evidenced the complex interaction between the RIP140 and E2F1 and showed that RIP140 represses E2F1 transactivation on various transiently transfected E2F-target promoters and inhibits the expression of several E2F1-target genes (such as CCNE1 and CCNB2). In agreement with a role for RIP140 in the control of E2F activity, we demonstrate that increasing RIP140 levels results in a reduction in the proportion of cells in S phase in various human cell lines. Finally, analysis of human breast cancers demonstrates that low RIP140 mRNA expression was associated with high E2F1-target gene levels and basal-like tumors. Conclusion This study demonstrates that RIP140 is a regulator of the E2F pathway which discriminates luminal- and basal-like tumors, emphasizing the importance of these regulations for a clinical cancer phenotype. PMID:20410059

Docquier, Aurélie; Harmand, Pierre-Olivier; Fritsch, Samuel; Chanrion, Maia; Darbon, Jean-Marie; Cavailles, Vincent

2010-01-01

175

Functional processing and secretion of Chikungunya virus E1 and E2 glycoproteins in insect cells  

PubMed Central

Background Chikungunya virus (CHIKV) is a mosquito-borne, arthrogenic Alphavirus that causes large epidemics in Africa, South-East Asia and India. Recently, CHIKV has been transmitted to humans in Southern Europe by invading and now established Asian tiger mosquitoes. To study the processing of envelope proteins E1 and E2 and to develop a CHIKV subunit vaccine, C-terminally his-tagged E1 and E2 envelope glycoproteins were produced at high levels in insect cells with baculovirus vectors using their native signal peptides located in CHIKV 6K and E3, respectively. Results Expression in the presence of either tunicamycin or furin inhibitor showed that a substantial portion of recombinant intracellular E1 and precursor E3E2 was glycosylated, but that a smaller fraction of E3E2 was processed by furin into mature E3 and E2. Deletion of the C-terminal transmembrane domains of E1 and E2 enabled secretion of furin-cleaved, fully processed E1 and E2 subunits, which could then be efficiently purified from cell culture fluid via metal affinity chromatography. Confocal laser scanning microscopy on living baculovirus-infected Sf21 cells revealed that full-length E1 and E2 translocated to the plasma membrane, suggesting similar posttranslational processing of E1 and E2, as in a natural CHIKV infection. Baculovirus-directed expression of E1 displayed fusogenic activity as concluded from syncytia formation. CHIKV-E2 was able to induce neutralizing antibodies in rabbits. Conclusions Chikungunya virus glycoproteins could be functionally expressed at high levels in insect cells and are properly glycosylated and cleaved by furin. The ability of purified, secreted CHIKV-E2 to induce neutralizing antibodies in rabbits underscores the potential use of E2 in a subunit vaccine to prevent CHIKV infections. PMID:21762510

2011-01-01

176

Polymorphic genetic characterization of E2 gene of bovine viral diarrhea virus in China.  

PubMed

Bovine viral diarrhea virus (BVDV) is one of the wide distributed pathogenic viruses of livestock and wild animals worldwide. E2 glycoprotein is a major structural component of the BVDV virion and plays a key role in viral attachment to host cells and inducing immune responses against viral infection. In order to gain detailed information of the E2 coding region of BVDV circulating in China, 46 positive samples were tested by RT-PCR for the E2 coding region. The 1122 nt nucleotide sequences of full-length E2 were harvested and analyzed. The results suggested that full-length E2 was an ideal target for BVDV genotyping and divided the domestic BVDV isolates into 9 subgenotypes, namely BVDV-1a, -1b1, -1c, -1d, -1o, -1m, -1p, -1q and BVDV-2a, showing great diversity. The difference of nonsynonymous and synonymous substitution rates (dN-dS) inferred both positive and purifying selection of the E2. However, combination of positive and purifying selection at different points indicated purifying selection within the complete E2. Protein properties analysis based on glycosylation sites and epitope prediction demonstrated that the biological character of E2 among individual BVDV subgenotype was similar, but may alter due to amino acid changes. For the first time, the comprehensive collection of E2 sequences of Chinese BVDV isolates was elucidated, which would provide information for future vaccine design and BVD control in China. PMID:25465669

Lang, Yifei; Gao, Shandian; Du, Junzheng; Shao, Junjun; Cong, Guozheng; Lin, Tong; Zhao, Furong; Liu, Lihong; Chang, Huiyun

2014-12-01

177

Arginine methylation-dependent reader-writer interplay governs growth control by E2F-1  

PubMed Central

Summary The mechanisms that underlie and dictate the different biological outcomes of E2F-1 activity have yet to be elucidated. We describe the residue-specific methylation of E2F-1 by the asymmetric dimethylating protein arginine methyltransferase (PRMT) 1 and symmetric dimethylating PRMT5, and relate the marks to different functional consequences of E2F-1 activity. Methylation by PRMT1 hinders methylation by PRMT5, which augments E2F-1-dependent apoptosis, whereas PRMT5-dependent methylation favours proliferation by antagonising methylation by PRMT1. The ability of E2F-1 to prompt apoptosis in DNA damaged cells coincides with enhanced PRMT1 methylation. In contrast, cyclin A binding to E2F-1 impedes PRMT1 methylation and augments PRMT5 methylation, thus ensuring that E2F-1 is locked into its cell cycle progression mode. The Tudor domain protein p100-TSN reads the symmetric methylation mark, and binding of p100-TSN down-regulates E2F-1 apoptotic activity. Our results define an exquisite level of precision in the reader-writer interplay that governs the biological outcome of E2F-1 activity. PMID:24076217

Zheng, Shunsheng; Moehlenbrink, Jutta; Lu, Yi-Chien; Zalmas, Lykourgos-Panagiotis; Sagum, Cari A.; Carr, Simon; McGouran, Joanna F.; Alexander, Leila; Fedorov, Oleg; Munro, Shonagh; Kessler, Benedikt; Bedford, Mark T.; Yu, Qiang; La Thangue, Nicholas B.

2014-01-01

178

Regulation of transcription factor E2F3a and its clinical relevance in ovarian cancer.  

PubMed

Recently we showed an integral epidermal growth factor receptor (EGFR)-E2F3a signaling path, in which E2F3a was found to be essential in EGFR-mediated proliferation in ovarian cancer cells. The present work evaluates the clinical relevance of this novel axis and of E2F3a itself in a large set of 130 ovarian cancer specimens. For this purpose E2F3a and its counterpart, E2F3b, were measured by RT-PCR and activated EGFR was assessed by immunohistochemistry. When compared with healthy control tissue, both E2F3 isoforms were overexpressed in the cancers, but only E2F3a expression correlated with tumor stage (?=0.349, P=0.0001) and residual disease (?=0.254, P=0.004). Univariate survival analyses showed E2F3a and activated EGFR to be associated with poor PFS and OS. Furthermore, a strong, positive correlation between activated EGFR and E2F3a expression was shown (P=0.0001). We further identified two EGFR-independent mechanisms that regulate E2F3a expression, namely one, acting by promoter methylation of miR-34a, which by its physical interaction with E2F3a transcripts causes their degradation, and the second based on 6p22 gene locus amplification. MiRIDIAN-based knockdown and induction of miR-34a evidenced a direct regulatory link between miR-34a and E2F3a, and the tumor-suppressive character of miR-34a was documented by its association with improved survival. Although, 6p22 gene locus amplification was detected in a significant number of ovarian cancer specimens, 6p22 ploidy was not relevant in predicting survival. In Cox regression analysis, E2F3a, but not activated EGFR or miR-34a expression, retained independent prognostic significance (PFS: hazards ratio 3.785 (1.326-9.840), P=0.013; OS: hazards ratio 4.651 (1.189-15.572), P=0.013). These clinical findings highlight the relevance of E2F3a in the biology of ovarian cancer. Moreover, identification of EGFR-independent mechanisms in E2F3a control can be helpful in explaining the non-responsiveness of therapeutic EGFR targeting in ovarian cancer. PMID:21516127

Reimer, D; Hubalek, M; Kiefel, H; Riedle, S; Skvortsov, S; Erdel, M; Hofstetter, G; Concin, N; Fiegl, H; Müller-Holzner, E; Marth, C; Altevogt, P; Zeimet, A G

2011-09-22

179

Prostaglandin E2 levels and platelet function are different in cord blood compared to adults.  

PubMed

Neonatal platelets support primary haemostasis and thrombin generation as well as adult platelets, despite observable hypoaggregability in vitro. High prostaglandin E2 levels at accouchement could account for inhibited platelet function via the EP4 receptor. We set out to determine prostaglandin E2 plasma levels in cord blood of healthy neonates and evaluate the impact of prostaglandin E2 on platelet function in adult and cord blood samples. Prostaglandin E2 plasma levels were measured in cord blood and venous adult blood using GC-MS. Impact of prostaglandin E2 on platelet aggregation was measured by spiking cord blood and adult samples. Contributions of EP3 and EP4 receptors were evaluated using respective antagonists. Intracellular cAMP concentrations were measured using a commercial ELISA-kit. Prostaglandin E2 plasma levels were substantially higher in cord blood than in adult samples. Spiking with prostaglandin E2 resulted in a slight but consistent reduction of platelet aggregation in adult blood, but response to PGE2 was blunted in cord blood samples. Aggregation response of spiked adult samples was still higher than with non-spiked cord blood samples. Blockage of EP4 receptors resulted in improved platelet aggregation in adult platelets upon prostaglandin E2 spiking, while aggregation in cord blood samples remained unaltered. Intracellular cAMP concentrations after preincubation with prostaglandin E2 were only increased in adult samples. In conclusion, very high prostaglandin E2 concentrations in cord blood affect platelet function. This effect may partially explain neonatal platelet hypoaggregability. Peak levels of prostaglandin E2 can potentially protect against birth stress-induced platelet activation. PMID:25118631

Schlagenhauf, A; Haidl, H; Leschnik, B; Leis, H-J; Heinemann, A; Muntean, W

2015-01-01

180

E2F-1:DP-1 induces p53 and overrides survival factors to trigger apoptosis.  

PubMed Central

The E2F DNA binding activity consists of a heterodimer between E2F and DP family proteins, and these interactions are required for association of E2F proteins with pRb and the pRb-related proteins p107 and p130, which modulate E2F transcriptional activities. E2F-1 expression is sufficient to release fibroblasts from G0 and induce entry into S phase, yet it also initiates apoptosis. To investigate the mechanisms of E2F-induced apoptosis, we utilized interleukin-3 (IL-3)-dependent 32D.3 myeloid cells, a model of hematopoietic progenitor programmed cell death. In the absence of IL-3, E2F-1 alone was sufficient to induce apoptosis, and p53 levels were diminished. DP-1 alone was not sufficient to induce cell cycle progression or alter rates of death following IL-3 withdrawal. However, overexpression of both E2F-1 and DP-1 led to the rapid death of cells even in the presence of survival factors. In the presence of IL-3, levels of endogenous wild-type p53 increased in response to E2F-1, and coexpression of DP-1 further augmented p53 levels. These results provide evidence that E2F is a functional link between the tumor suppressors p53 and pRb. However, induction of p53 alone was not sufficient to trigger apoptosis, suggesting that the ability of E2F to override survival factors involves additional effectors. PMID:8524253

Hiebert, S W; Packham, G; Strom, D K; Haffner, R; Oren, M; Zambetti, G; Cleveland, J L

1995-01-01

181

The First Human Epitope Map of the Alphaviral E1 and E2 Proteins Reveals a New E2 Epitope with Significant Virus Neutralizing Activity  

PubMed Central

Background Venezuelan equine encephalitis virus (VEEV) is responsible for VEE epidemics that occur in South and Central America and the U.S. The VEEV envelope contains two glycoproteins E1 (mediates cell membrane fusion) and E2 (binds receptor and elicits virus neutralizing antibodies). Previously we constructed E1 and E2 epitope maps using murine monoclonal antibodies (mMAbs). Six E2 epitopes (E2c,d,e,f,g,h) bound VEEV-neutralizing antibody and mapped to amino acids (aa) 182–207. Nothing is known about the human antibody repertoire to VEEV or epitopes that engage human virus-neutralizing antibodies. There is no specific treatment for VEE; however virus-neutralizing mMAbs are potent protective and therapeutic agents for mice challenged with VEEV by either peripheral or aerosol routes. Therefore, fully human MAbs (hMAbs) with virus-neutralizing activity should be useful for prevention or clinical treatment of human VEE. Methods We used phage-display to isolate VEEV-specific hFabs from human bone marrow donors. These hFabs were characterized by sequencing, specificity testing, VEEV subtype cross-reactivity using indirect ELISA, and in vitro virus neutralization capacity. One E2-specific neutralizing hFAb, F5n, was converted into IgG, and its binding site was identified using competitive ELISA with mMAbs and by preparing and sequencing antibody neutralization-escape variants. Findings Using 11 VEEV-reactive hFabs we constructed the first human epitope map for the alphaviral surface proteins E1 and E2. We identified an important neutralization-associated epitope unique to the human immune response, E2 aa115–119. Using a 9 Å resolution cryo-electron microscopy map of the Sindbis virus E2 protein, we showed the probable surface location of this human VEEV epitope. Conclusions The VEEV-neutralizing capacity of the hMAb F5 nIgG is similar to that exhibited by the humanized mMAb Hy4 IgG. The Hy4 IgG has been shown to limit VEEV infection in mice both prophylactically and therapeutically. Administration of a cocktail of F5n and Hy4 IgGs, which bind to different E2 epitopes, could provide enhanced prophylaxis or immunotherapy for VEEV, while reducing the possibility of generating possibly harmful virus neutralization-escape variants in vivo. PMID:20644615

Hunt, Ann R.; Frederickson, Shana; Maruyama, Toshiaki; Roehrig, John T.; Blair, Carol D.

2010-01-01

182

Altered subcellular distribution of estrogen receptor alpha is implicated in estradiol-induced dual regulation of insulin signaling in 3T3-L1 adipocytes.  

PubMed

We investigated the mechanisms by which estrogen alters insulin signaling in 3T3-L1 adipocytes. Treatment with 17beta-estradiol (E2) did not affect insulin-induced tyrosine phosphorylation of insulin receptor. E2 enhanced insulin-induced tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), IRS-1/p85 association, phosphorylation of Akt, and 2-deoxyglucose uptake at 10(-8) m, but inhibited these effects at 10(-5) m. A concentration of 10(-5) m E2 enhanced insulin-induced phosphorylation of IRS-1 at Ser(307), which was abolished by treatment with a c-Jun NH(2)-terminal kinase inhibitor. In addition, the effect of E2 was abrogated by pretreatment with a specific estrogen receptor antagonist, ICI182,780. Membrane-impermeable E2, E2-BSA, did not affect the insulin-induced phosphorylation of Akt at 10(-8) m, but inhibited it at 10(-5) m. Furthermore, E2 decreased the amount of estrogen receptor alpha at the plasma membrane at 10(-8) m, but increased it at 10(-5) m. In contrast, the subcellular distribution of estrogen receptor beta was not altered by the treatment. These results indicate that E2 affects the metabolic action of insulin in a concentration-specific manner, that high concentrations of E2 inhibit insulin signaling by modulating phosphorylation of IRS-1 at Ser(307) via a c-Jun NH(2)-terminal kinase-dependent pathway, and that the subcellular redistribution of estrogen receptor alpha in response to E2 may explain the dual effect of E2. PMID:16269459

Nagira, Kiyofumi; Sasaoka, Toshiyasu; Wada, Tsutomu; Fukui, Kazuhito; Ikubo, Mariko; Hori, Satoko; Tsuneki, Hiroshi; Saito, Shigeru; Kobayashi, Masashi

2006-02-01

183

Naloxone acts as an antagonist of estrogen receptor activity in MCF-7 cells.  

PubMed

Estrogen promotes the growth of breast cancer via estrogen receptors (ER). Earlier studies showed that the opioid receptor antagonist naloxone inhibits MCF-7 breast cancer growth in mice. We examined the cellular and molecular mechanism of naloxone antagonism of ERalpha activity in human MCF-7 cells. Naloxone (100 nmol/L) inhibited 17beta-estradiol (E2)-induced (10 nmol/L) MCF-7 cell proliferation by 65% and mitogen-activated protein kinase/extracellular signal-regulated kinase phosphorylation. Naloxone blocked the E2-induced activation of ERalpha, with 85% inhibition after 5 minutes and 100% recovery after 60 minutes. This assay is based on quantitation of E2-activated nuclear ERalpha binding to the immobilized coactivator peptide. A significant decrease in E2-induced ERalpha transactivation was observed in the presence of naloxone in the estrogen response element-luciferase reporter assay (P < 0.05, E2 versus E2 + naloxone). Naloxone also blocked E2-induced down-regulation of ERalpha mRNA at 30 minutes and 6 hours. Although naloxone inhibits ERalpha activity directly, it also induces a cross-talk between mu-opioid receptor (MOR) and ERalpha. Immunoprecipitates with anti-MOR antibody showed the presence of ERalpha in cells incubated with E2 in the presence of naloxone but not in cells incubated with E2 or naloxone alone. Higher amounts of ERalpha associated with MOR after 60 minutes compared with 10 minutes of incubation. Naloxone inhibited E2-bovine serum albumin-FITC binding to plasma membrane-associated ERalpha and also inhibited the direct binding of [3H]E2 to ERalpha. Thus, naloxone modulates ERalpha activity directly as well as indirectly via MOR. This study suggests that naloxone-like compounds can be developed as novel therapeutic molecules for breast cancer therapy. PMID:16546975

Farooqui, Mariya; Geng, Zhen H; Stephenson, Elliot J; Zaveri, Nurulain; Yee, Douglas; Gupta, Kalpna

2006-03-01

184

76 FR 52667 - International Conference on Harmonisation; Guidance on E2F Development Safety Update Report...  

Federal Register 2010, 2011, 2012, 2013

...Guidance on E2F Development Safety Update Report...Availability AGENCY: Food and Drug Administration...SUMMARY: The Food and Drug Administration...entitled ``E2F Development Safety Update Report...Communication, Outreach and Development (HFM-40), Center...Evaluation and Research, Food and Drug...

2011-08-23

185

17 CFR 270.30e-2 - Reports to shareholders of unit investment trusts.  

Code of Federal Regulations, 2010 CFR

...shareholders of unit investment trusts. 270.30e-2 ...30e-2 Commodity and Securities Exchanges SECURITIES...shareholders of unit investment trusts. (a) At least...registered unit investment trust substantially all the assets of which consist of securities issued by a...

2010-04-01

186

17 CFR 270.30e-2 - Reports to shareholders of unit investment trusts.  

Code of Federal Regulations, 2013 CFR

...shareholders of unit investment trusts. 270.30e-2 ...30e-2 Commodity and Securities Exchanges SECURITIES...shareholders of unit investment trusts. (a) At least...registered unit investment trust substantially all the assets of which consist of securities issued by a...

2013-04-01

187

17 CFR 270.30e-2 - Reports to shareholders of unit investment trusts.  

Code of Federal Regulations, 2012 CFR

...shareholders of unit investment trusts. 270.30e-2 ...30e-2 Commodity and Securities Exchanges SECURITIES...shareholders of unit investment trusts. (a) At least...registered unit investment trust substantially all the assets of which consist of securities issued by a...

2012-04-01

188

17 CFR 270.30e-2 - Reports to shareholders of unit investment trusts.  

...shareholders of unit investment trusts. 270.30e-2 ...30e-2 Commodity and Securities Exchanges SECURITIES...shareholders of unit investment trusts. (a) At least...registered unit investment trust substantially all the assets of which consist of securities issued by a...

2014-04-01

189

17 CFR 270.30e-2 - Reports to shareholders of unit investment trusts.  

Code of Federal Regulations, 2011 CFR

...shareholders of unit investment trusts. 270.30e-2 ...30e-2 Commodity and Securities Exchanges SECURITIES...shareholders of unit investment trusts. (a) At least...registered unit investment trust substantially all the assets of which consist of securities issued by a...

2011-04-01

190

The recognition of local DNA conformation by the human papillomavirus type 6 E2 protein  

E-print Network

The recognition of local DNA conformation by the human papillomavirus type 6 E2 protein Elizabeth; Accepted June 16, 2006 ABSTRACT The E2 proteins are transcription/replication factors from papillomaviruses. Human papillomaviruses (HPVs) can be broadly divided in two groups; low- risk HPV subtypes cause benign

Gaston, Kevin

191

p53 represses human papillomavirus type 16 DNA replication via the viral E2 protein  

Microsoft Academic Search

BACKGROUND: Human papillomavirus (HPV) DNA replication can be inhibited by the cellular tumour suppressor protein p53. However, the mechanism through which p53 inhibits viral replication and the role that this might play in the HPV life cycle are not known. The papillomavirus E2 protein is required for efficient HPV DNA replication and also regulates viral gene expression. E2 represses transcription

Craig Brown; Anna M Kowalczyk; Ewan R Taylor; Iain M Morgan; Kevin Gaston

2008-01-01

192

NRIP enhances HPV gene expression via interaction with either GR or E2  

SciTech Connect

We previously identified a gene, nuclear receptor-interaction protein (NRIP), which functions as a transcription cofactor in glucocorticoid receptor (GR) and human papillomavirus E2 (HPV E2)-driven gene expression. Here, we comprehensively evaluated the role of NRIP in HPV-16 gene expression. NRIP acts as a transcription cofactor to enhance GR-regulated HPV-16 gene expression in the presence of hormone. NRIP also can form complex with E2 that caused NRIP-induced HPV gene expression via E2-binding sites in a hormone-independent manner. Furthermore, NRIP can associate with GR and E2 to form tri-protein complex to activate HPV gene expression via GRE, not the E2-binding site, in a hormone-dependent manner. These results indicate that NRIP and GR are viral E2-binding proteins and that NRIP regulates HPV gene expression via GRE and/or E2 binding site in the HPV promoter in a hormone-dependent or independent manner, respectively.

Chang, Szu-Wei; Lu, Pei-Yu; Guo, Jih-Huong [Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China)] [Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Tsai, Tzung-Chieh [Department of Microbiology and Immunology, National Chiayi University, Chiayi 600-04, Taiwan (China)] [Department of Microbiology and Immunology, National Chiayi University, Chiayi 600-04, Taiwan (China); Tsao, Yeou-Ping [Department of Ophthalmology, Mackay Memorial Hospital, Taipei 104, Taiwan (China)] [Department of Ophthalmology, Mackay Memorial Hospital, Taipei 104, Taiwan (China); Chen, Show-Li, E-mail: showlic@ha.mc.ntu.edu.tw [Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China)] [Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China)

2012-02-05

193

Complete Genome Sequence of the Autographa californica Multiple Nucleopolyhedrovirus Strain E2  

PubMed Central

Many vectors that are commonly used in the baculovirus/insect cell system (BICS) are derived from the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) strain E2. To facilitate work with these vectors, we sequenced the E2 genome, compared it to that of the AcMNPV C6 strain, and found that they are very similar overall. PMID:25502662

Maghodia, Ajay B.; Jarvis, Donald L.

2014-01-01

194

E2F Inhibition Synergizes with Paclitaxel in Lung Cancer Cell Lines  

PubMed Central

The CDK/Rb/E2F pathway is commonly disrupted in lung cancer, and thus, it is predicted that blocking the E2F pathway would have therapeutic potential. To test this hypothesis, we have examined the activity of HLM006474 (a small molecule pan-E2F inhibitor) in lung cancer cell lines as a single agent and in combination with other compounds. HLM006474 reduces the viability of both SCLC and NSCLC lines with a biological IC50 that varies between 15 and 75 µM, but with no significant difference between the groups. Combination of HLM006474 with cisplatin and gemcitabine demonstrate little synergy; however, HLM006474 synergizes with paclitaxel. Surprisingly, we discovered that brief treatment of cells with HLM006474 led to an increase of E2F3 protein levels (due to de-repression of these promoter sites). Since paclitaxel sensitivity has been shown to correlate with E2F3 levels, we hypothesized that HLM006474 synergy with paclitaxel may be mediated by transient induction of E2F3. To test this, H1299 cells were depleted of E2F3a and E2F3b with siRNA and treated with paclitaxel. Assays of proliferation showed that both siRNAs significantly reduced paclitaxel sensitivity, as expected. Taken together, these results suggest that HLM006474 may have efficacy in lung cancer and may be useful in combination with taxanes. PMID:24831239

Kurtyka, Courtney A.; Chen, Lu; Cress, W. Douglas

2014-01-01

195

Conserved interaction of the papillomavirus E2 transcriptional activator proteins with human and yeast TFIIB proteins.  

PubMed Central

Papillomavirus early gene expression is regulated by the virus gene-encoded E2 proteins. The best-characterized E2 protein, encoded by bovine papillomavirus type 1 (BPV-1), has been shown to interact with basal transcription factor IIB (TFIIB) and the TATA binding protein basal transcription factor (N. M. Rank and P. F. Lambert, J. Virol. 69:6323-6334, 1995). We demonstrate that the potent E2 transcriptional activator protein encoded by a gene of human PV type 16 also interacts with TFIIB in vitro. Moreover, a direct comparison of domains within human TFIIB (hTFIIB) required for VP16 and BPV-1 E2 indicates that these acidic activators interact with hTFIIB in a qualitatively similar manner. Our mapping experiments identify hTFIIB interaction domains within the amino-terminal activation domain of BPV-1 E2. Finally, we demonstrate in vitro interaction between Saccharomyces cerevisiae TFIIB and BPV-1 E2, an observation that is consistent with the importance of the E2-TFIIB interaction for BPV-1 E2 transactivation in both systems. PMID:9311902

Benson, J D; Lawande, R; Howley, P M

1997-01-01

196

Complete Genome Sequence of the Autographa californica Multiple Nucleopolyhedrovirus Strain E2.  

PubMed

Many vectors that are commonly used in the baculovirus/insect cell system (BICS) are derived from the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) strain E2. To facilitate work with these vectors, we sequenced the E2 genome, compared it to that of the AcMNPV C6 strain, and found that they are very similar overall. PMID:25502662

Maghodia, Ajay B; Jarvis, Donald L; Geisler, Christoph

2014-01-01

197

Multimodal regulation of E2F1 gene expression by progestins.  

PubMed

An analysis of mRNA expression in T47D breast cancer cells treated with the synthetic progestin R5020 revealed a subset of progesterone receptor (PR) target genes that are enriched for E2F binding sites. Following up on this observation, we determined that PR-B acts in both direct and indirect manners to positively upregulate E2F1 expression in T47D cells. The direct effects of PR on E2F1 expression were confirmed by chromatin immunoprecipitation (ChIP) analysis, which indicated that the agonist-bound receptor was recruited to several enhancer elements proximal to the E2F1 transcript. However, we also noted that cycloheximide partially inhibits R5020 induction of E2F1 expression, indicating that the ligand-dependent actions of PR on this gene may involve additional indirect regulatory pathways. In support of this hypothesis, we demonstrated that treatment with R5020 significantly increases both hyperphosphorylation of Rb and recruitment of E2F1 to its own promoter, thus activating a positive feedback loop that further amplifies its transcription. Furthermore, we established that PR-mediated induction of Krüppel-like factor 15 (KLF15), which can bind to GC-rich DNA within the E2F1 promoter, is required for maximal induction of E2F1 expression by progestins. Taken together, these results suggest a new paradigm for multimodal regulation of target gene expression by PR. PMID:20123965

Wade, Hilary E; Kobayashi, Sakiko; Eaton, Matthew L; Jansen, Michelle S; Lobenhofer, Edward K; Lupien, Mathieu; Geistlinger, Timothy R; Zhu, Wencheng; Nevins, Joseph R; Brown, Myles; Otteson, Deborah C; McDonnell, Donald P

2010-04-01

198

Effects of estrogen and gender on cataractogenesis induced by high-LET radiation  

SciTech Connect

Planning for long-duration manned lunar and interplanetary missions requires an understanding of radiation-induced cataractogenesis. Previously, it was demonstrated that low-linear energy transfer (LET) irradiation with 10 Gy of {sup 60}Co {gamma} rays resulted in an increased incidence of cataracts in male rats compared to female rats. This gender difference was not due to differences in estrogen, since male rats treated with the major secreted estrogen 17-{beta}-estradiol (E2) showed an identical increase compared to untreated males. We now compare the incidence and rate of progression of cataracts induced by high-LET radiation in male and female Sprague-Dawley rats. Rats received a single dose of 1 Gy of 600 MeV {sup 56}Fe ions. Lens opacification was measured at 2-4 week intervals with a slit lamp. The incidence and rate of progression of radiation-induced cataracts was significantly increased in the animals in which estrogen was available from endogenous or exogenous sources. Male rats with E2 capsules implanted had significantly higher rates of progression compared to male rats with empty capsules implanted (P = 0.025) but not compared to the intact female rats. These results contrast with data obtained after low-LET irradiation and suggest the possibility that the different types of damage caused by high- and low-LET radiation may be influenced differentially by steroid sex hormones.

Henderson, M.A.; Rusek, A.; Valluri, S.; Garrett, J.; Lopez, J.; Caperell-Grant, A.; Mendonca, M.; Bigsby, R.; Dynlacht, J.

2010-02-01

199

Estrogenic endocrine disruptive components interfere with calcium handling and differentiation of human trophoblast cells.  

PubMed

During development, calcium (Ca) is actively transported by placental trophoblasts to meet fetal nutritional and the skeletal mineralization needs. Maternal exposure to estrogenic pesticides, such as 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT) and methoxychlor (MTC), has been shown to result in reproductive disorders and/or abnormal fetal development. In this study, we have examined the effects of exposure of trophoblastic cells to MTC and DTT, in comparison to 17beta-estradiol (E2) and diethylstilbestrol (DES), to test the hypothesis that cellular Ca handling is a target for these endocrine disruptive components. Treatment with DDT, MTC, DES, or E2 increased cellular Ca uptake, and the expression of trophoblast-specific human Ca binding protein (HCaBP) was down-regulated by both MTC and DDT. Treatment with MTC, DDT, and DES inhibited cell proliferation, induced apoptosis, and suppressed expression of several trophoblast differentiation marker genes. These effects were reversed by overexpression of metallothionein IIa, a gene highly responsive to cadmium and other metals. These results strongly suggest that trophoblast Ca handling functions are endocrinally modulated, and that their alteration by candidate endocrine disruptors, such as MTC and DDT, constitutes a possible pathway of the harmful effects of these components on fetal development. PMID:12858341

Derfoul, A; Lin, F J; Awumey, E M; Kolodzeski, T; Hall, D J; Tuan, R S

2003-07-01

200

Reproductive disruption in fish downstream from an estrogenic wastewater effluent.  

PubMed

To assess the impact of an estrogenic wastewater treatment plant (WWTP) effluent on fish reproduction, white suckers (Catostomus commersoni) were collected from immediately upstream and downstream (effluent site) of the city of Boulder, CO, WWTP outfall. Gonadal intersex, altered sex ratios, reduced gonad size, disrupted ovarian and testicular histopathology, and vitellogenin induction consistent with exposure to estrogenic wastewater contaminants were identified in white suckers downstream from the WWTP outfall and not at the upstream site. The sex ratio was female-biased at the effluent site in both the fall of 2003 and the spring of 2004; the frequency of males at the effluent site (17-21%) was half that of the upstream site (36-46%). Intersex white suckers comprised 18-22% of the population at the effluent site. Intersex fish were not found at the upstream site. Chemical analyses determined that the WWTP effluent contained a complex mixture of endocrine-active chemicals, including 17beta-estradiol (E2) 17alpha-ethynylestradiol, alkylphenols, and bisphenol A resulting in an estimated total estrogen equivalence of up to 31 ng E2 L(-1). These results indicate that the reproductive potential of native fishes may be compromised in wastewater-dominated streams. PMID:18522126

Vajda, Alan M; Barber, Larry B; Gray, James L; Lopez, Elena M; Woodling, John D; Norris, David O

2008-05-01

201

In vivo visual reporter system for detection of estrogen-like substances by transgenic medaka.  

PubMed

Detection of endocrine disrupting chemicals, in particular, environmental estrogens with living organisms, has many advantages if compared to chemical analysis. The screening of novel pollutants with meaningful endpoints, the integration of uptake, bioconcentration, and excretion as well as the evaluation of endocrine disrupting effects with respect to toxicity require in vivo biotests for estrogen-like substances (ELSs). Critical disadvantages of whole organism biotests are their low sensitivity and the need for laborious and time-consuming work. To overcome these problems, we have developed a transgenic medaka strain harboring the green fluorescence protein (GFP) gene driven by choriogenin H gene regulatory elements. Choriogenin H is an egg envelope protein induced by estrogens in the liver. With yolk sac larvae of this strain, GFP induction in liver was observed 24 h after onset of aqueous exposure to 0.63 nM 17beta-estradiol (E2), 0.34 nM ethynylestradiol, or 14.8 nM estrone. Furthermore, concentrated sewage treatment effluent induced GFP expression. Comparison of E2 equivalents estimated by GFP-induction in transgenic medaka, a YES assay, and GC/MS showed detection limits in the same order of magnitude. These results indicated that the sensitivity of the transgenic medaka strain was sufficient for application as an alternative model in monitoring environmental water samples for ELSs. PMID:15884374

Kurauchi, Kanta; Nakaguchi, Yoshitsugu; Tsutsumi, Makiko; Hori, Hirosi; Kurihara, Ryo; Hashimoto, Shinya; Ohnuma, Ryoko; Yamamoto, Yoshikazu; Matsuoka, Sumiko; Kawai, Shin'Ichiro; Hirata, Takashi; Kinoshita, Masato

2005-04-15

202

Profiles of sex steroids, fecundity, and spawning of the curimatã-pacu Prochilodus argenteus in the São Francisco River, downstream from the Três Marias Dam, Southeastern Brazil.  

PubMed

The present study evaluated for the first time sex steroid profiles and fecundity in females of Prochilodus argenteus from two sections of the São Francisco River Brazil, downstream from the Três Marias Dam, which influences characteristics of their water habitat. The model species in the study, P. argenteus, is an important commercial and recreational species in Brazil. In the region closest to the dam (section 1), females did not reach final oocyte maturation, failed to spawn, and displayed lesser circulating concentrations of testosterone, 17(-hydroxyprogesterone (17(-P) and 17beta-estradiol (E2) than those farther downstream of the dam (section 2). The endocrine and fecundity deficiencies probably are attributed to lower water temperature and oxygen concentration in (section 1). The follicular atresia rate in the region closest to the dam (26%) was greater than those fish captured farther downstream of the dam (13%), after the Abaeté River (section 2). Variations in testosterone, E2 and 17(-P concentrations in section 2, followed gonadal maturation which are typical features of species which have seasonal reproduction, group-synchronous oocyte development, and are single batch spawners such as P. argenteus. Results document the first evidence of endocrine and reproductive dysfunctions caused by inadequate water conditions in a wild population of the migratory species P. argenteus in the São Francisco River, downstream from the Três Marias dam. PMID:19683404

Arantes, Fábio P; Santos, Helio B; Rizzo, Elizete; Sato, Yoshimi; Bazzoli, Nilo

2010-04-01

203

Molecular epidemiology of breast cancer: a review.  

PubMed

The standard paradigm providing a general mechanistic explanation for the association of cumulative, excessive oestrogen exposure and breast cancer risk is that the proliferative stimulus provided by 17 beta-estradiol (E2) leads to the appearance of spontaneous mutations. Thus, the key contribution of E2 is the stimulation of breast epithelial cell proliferation. However, mounting evidence supports a complimentary pathway involving direct (oestrogen-quinone DNA adducts) and indirect (oxidative DNA damage via redox cycling) genotoxicity originating from oestrogen metabolites. While mutations in high penetrance genes such as BRCA1, BRCA2 and p53 confer a high risk for an individual, they represent a low overall attributable risk due to low allele frequencies in the population. On the other hand, mutations in phases I and II enzyme genes involved in xenobiotic and endobiotic metabolism, including genes encoding CYP1A1, N-acetyltransferase 2 and glutathione-S-transferase (GST) isoforms M1 (null), T1 (null), and P1 (low-activity allele), might confer a low relative cancer risk for an individual. However, because these mutations seem to be common among individuals, they represent a high attributable risk category of genes. The intent of this review is to examine current literature on the molecular epidemiology of breast cancer with emphasis on the role of polymorphisms in high and low penetrance genes on susceptibility to breast cancer. PMID:15055143

Okobia, M N; Bunker, C H

2003-12-01

204

The G protein-coupled receptor GPR30 mediates the proliferative and invasive effects induced by hydroxytamoxifen in endometrial cancer cells  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We assessed hydroxytamoxifen (OHT) effects in two endometrial cancer cell lines. Black-Right-Pointing-Pointer GPR30 mediates the proliferative effects induced by OHT. Black-Right-Pointing-Pointer GPR30 mediates the invasive effects induced by OHT. Black-Right-Pointing-Pointer GPR30 expression was up-regulated by OHT in endometrial cancer cell line. -- Abstract: The selective ER modulator tamoxifen (TAM) is the most widely used ER antagonist for treatment of women with hormone-dependent breast tumor. However, long-term treatment is associated with an increased risk of endometrial cancer. The aim of the present study was to demonstrate new insight into the role of G-protein coupled receptor 30 (GPR30) in the activity of TAM, which promoted endometrial cancer. In endometrial cancer cell lines ISHIKAWA and KLE, the potential of 4-hydroxytamoxifen (OHT), the active metabolite of TAM, 17{beta}-estradiol (E2) and G1, a non-steroidal GPR30-specific agonist to promote cell proliferation and invasion was evaluated. All agents above induced high proliferative and invasive effects, while the down-regulation of GPR30 or the interruption of MAPK signal pathway partly or completely prevented the action of the regent. Moreover, the RNA and protein expression of GPR30 was up-regulated by G1, E2 or OHT in both cell lines. The present study provided a new insight into the mechanism involved in the agonistic activity exerted by TAM in the uterus.

Du, Gui-Qiang; Zhou, Long; Chen, Xiao-Yue [Department of Obstetrics and Gynecology, The International Peace Maternity and Child Health Hospital of the China Welfare Institute Affiliated to Shanghai Jiao Tong University, 910, Hengshan Road, Shanghai (China)] [Department of Obstetrics and Gynecology, The International Peace Maternity and Child Health Hospital of the China Welfare Institute Affiliated to Shanghai Jiao Tong University, 910, Hengshan Road, Shanghai (China); Wan, Xiao-Ping, E-mail: wanxiaoping61@126.com [Department of Obstetrics and Gynecology, The International Peace Maternity and Child Health Hospital of the China Welfare Institute Affiliated to Shanghai Jiao Tong University, 910, Hengshan Road, Shanghai (China)] [Department of Obstetrics and Gynecology, The International Peace Maternity and Child Health Hospital of the China Welfare Institute Affiliated to Shanghai Jiao Tong University, 910, Hengshan Road, Shanghai (China); He, Yin-Yan [Department of Obstetrics and Gynecology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai (China)] [Department of Obstetrics and Gynecology, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai (China)

2012-04-06

205

Nitric oxide sensitive-guanylyl cyclase subunit expression changes during estrous cycle in anterior pituitary glands.  

PubMed

17beta-estradiol (E2) exerts inhibitory actions on the nitric oxide pathway in rat adult pituitary glands. Previously, we reported that in vivo E2 acute treatment had opposite effects on soluble guanylyl cyclase (sGC) subunits, increasing alpha1- and decreasing beta1-subunit protein and mRNA expression and decreasing sGC activity in immature rats. Here we studied the E2 effect on sGC protein and mRNA expression in anterior pituitary gland from adult female rats to address whether the maturation of the hypothalamus-pituitary axis influences its effects and to corroborate whether these effects occur in physiological conditions such as during estrous cycle. E2 administration causes the same effect on sGC as seen in immature rats, and these effects are estrogen receptor dependent. These results suggest that E2 is the main effector of these changes. Since the sGC alpha-subunit increases while the sGC activity decreases, we studied if other less active isoforms of the sGC alpha-subunit are expressed. Here we show for the first time that sGCalpha2 and sGCalpha2 inhibitory (alpha2i) isoforms are expressed in this gland, but only sGCalpha2i mRNA increased after E2 acute treatment. Finally, to test whether E2 effects take place under a physiological condition, sGC subunit expression was monitored over estrous cycle. sGCalpha1, -beta1, and -alpha2i fluctuate along estrous cycle, and these changes are directly related with E2 level fluctuations rather than to NO level variations. These findings show that E2 physiologically regulates sGC expression and highlight a novel mechanism by which E2 downregulates sGC activity in rat anterior pituitary gland. PMID:19141686

Cabilla, Jimena P; Ronchetti, Sonia A; Nudler, Silvana I; Miler, Eliana A; Quinteros, Fernanda A; Duvilanski, Beatriz H

2009-04-01

206

Direct visualization of Agrobacterium-delivered VirE2 in recipient cells  

PubMed Central

Agrobacterium tumefaciens is a natural genetic engineer widely used to deliver DNA into various recipients, including plant, yeast and fungal cells. The bacterium can transfer single-stranded DNA molecules (T–DNAs) and bacterial virulence proteins, including VirE2. However, neither the DNA nor the protein molecules have ever been directly visualized after the delivery. In this report, we adopted a split-GFP approach: the small GFP fragment (GFP11) was inserted into VirE2 at a permissive site to create the VirE2-GFP11 fusion, which was expressed in A. tumefaciens; and the large fragment (GFP1–10) was expressed in recipient cells. Upon delivery of VirE2-GFP11 into the recipient cells, GFP fluorescence signals were visualized. VirE2-GFP11 was functional like VirE2; the GFP fusion movement could indicate the trafficking of Agrobacterium-delivered VirE2. As the natural host, all plant cells seen under a microscope received the VirE2 protein in a leaf-infiltration assay; most of VirE2 moved at a speed of 1.3–3.1 ?m sec?1 in a nearly linear direction, suggesting an active trafficking process. Inside plant cells, VirE2-GFP formed filamentous structures of different lengths, even in the absence of T-DNA. As a non-natural host recipient, 51% of yeast cells received VirE2, which did not move inside yeast. All plant cells seen under a microscope transiently expressed the Agrobacterium-delivered transgene, but only 0.2% yeast cells expressed the transgene. This indicates that Agrobacterium is a more efficient vector for protein delivery than T-DNA transformation for a non-natural host recipient: VirE2 trafficking is a limiting factor for the genetic transformation of a non-natural host recipient. The split-GFP approach could enable the real-time visualization of VirE2 trafficking inside recipient cells. PMID:24299048

Li, Xiaoyang; Yang, Qinghua; Tu, Haitao; Lim, Zijie; Pan, Shen Q

2014-01-01

207

Specific estrogen-induced cell proliferation of cultured Syrian hamster renal proximal tubular cells in serum-free chemically defined media  

SciTech Connect

It has long been recognized that the renal proximal tubular epithelium of the hamster is a bona fide estrogen target tissue. The effect of estrogens on the growth of proximal tubule cell explants and dissociated single cells derived from these explant outgrowths has been studied in culture. Renal tubular cells were grown on a PF-HR-9 basement membrane under serum-free chemically defined culture conditions. At 7-14 days in culture, cell number was enhanced 3-fold in the presence of either 17{beta}-estradiol or diethylstilbestrol. A similar 3-fold increase in cell number was also seen at 1 nM 17{beta}-estradiol in subcultured dissociated single tubular cells derived from hamster renal tubular explant outgrowths at 21 days in culture. Concomitant exposure of tamoxifen at 3-fold molar excess in culture completely abolished the increase in cell number seen with 17{beta}-estradiol. The proliferation effect of estrogens on proximal tubular cell growth appears to be species specific since 17{beta}-estradiol did not alter the growth of either rat or guinea pig proximal tubules in culture. In addition, at 7-10 days in culture in the presence of 17{beta}-estradiol, ({sup 3}H)thymidine labeling of hamster tubular cells was enhanced 3-fold. These results clearly indicate that estrogens can directly induce primary epithelial cell proliferation at physiologic concentrations and provide strong additional evidence for an important hormonal role in the neoplastic transformation of the hamster kidney.

Oberley, T.D.; Lauchner, L.J.; Pugh, T.D.; Gonzalez, A.; Goldfarb, S. (Univ. of Wisconsin Medical School, Madison (USA)); Li, S.A.; Li, J.J. (Univ. of Minnesota Medical School, Minneapolis (USA))

1989-03-01

208

p45 NF-E2 regulates expression of thromboxane synthase in megakaryocytes.  

PubMed Central

Transcription factor p45 NF-E2 is highly expressed in the erythroid and megakaryocytic lineages. Although p45 recognizes regulatory regions of several erythroid genes, mice deficient for this protein display only mild dyserythropoiesis but have abnormal megakaryocytes and lack circulating platelets. A number of megakaryocytic marker genes have been extensively studied, but none of them is regulated by NF-E2. To find target genes for p45 NF-E2 in megakaryopoiesis, we used an in vivo immunoselection assay: genomic fragments bound to p45 NF-E2 in the chromatin of a megakaryocytic cell line were immunoprecipitated with an anti-p45 antiserum and cloned. One of these fragments belongs to the second intron of the thromboxane synthase gene (TXS). We demonstrate that the TXS gene, which is mainly expressed in megakaryocytes, is indeed directly regulated by p45 NF-E2. First, its promoter contains a functional NF-E2 binding site; second, the intronic NF-E2 binding site is located within a chromatin-dependent enhancer element; third, p45-null murine megakaryocytes do not express detectable TXS mRNA, although TXS expression can be detected in other cells. These data, and the structure of the TXS promoter and enhancer, suggest that TXS belongs to a distinct subgroup of genes involved in platelet formation and function. PMID:9312024

Deveaux, S; Cohen-Kaminsky, S; Shivdasani, R A; Andrews, N C; Filipe, A; Kuzniak, I; Orkin, S H; Roméo, P H; Mignotte, V

1997-01-01

209

The RIP140 Gene Is a Transcriptional Target of E2F1  

PubMed Central

RIP140 is a transcriptional coregulator involved in energy homeostasis and ovulation which is controlled at the transcriptional level by several nuclear receptors. We demonstrate here that RIP140 is a novel target gene of the E2F1 transcription factor. Bioinformatics analysis, gel shift assay, and chromatin immunoprecipitation demonstrate that the RIP140 promoter contains bona fide E2F response elements. In transiently transfected MCF-7 breast cancer cells, the RIP140 promoter is transactivated by overexpression of E2F1/DP1. Interestingly, RIP140 mRNA is finely regulated during cell cycle progression (5-fold increase at the G1/S and G2/M transitions). The positive regulation by E2F1 requires sequences located in the proximal region of the promoter (?73/+167), involves Sp1 transcription factors, and undergoes a negative feedback control by RIP140. Finally, we show that E2F1 participates in the induction of RIP140 expression during adipocyte differentiation. Altogether, this work identifies the RIP140 gene as a new transcriptional target of E2F1 which may explain some of the effect of E2F1 in both cancer and metabolic diseases. PMID:22629304

Docquier, Aurélie; Augereau, Patrick; Lapierre, Marion; Harmand, Pierre-Olivier; Badia, Eric; Annicotte, Jean-Sébastien; Fajas, Lluis; Cavaillès, Vincent

2012-01-01

210

E2F3 plays an essential role in cardiac development and function  

PubMed Central

The E2F transcription factors are key downstream targets of the retinoblastoma protein tumor suppressor. They are known to regulate the expression of genes that control fundamental biological processes including cellular proliferation, apoptosis and differentiation. However, considerable questions remain about the precise roles of the individual E2F family members. This study shows that E2F3 is essential for normal cardiac development. E2F3-loss impairs the proliferative capacity of the embryonic myocardium and most E2f3?/? mice die in utero or perinatally with hypoplastic ventricular walls and/or severe atrial and ventricular septal defects. A small fraction of the E2f3?/? neonates have hearts that appear grossly normal and they initially survive. However, these animals develop ultrastructural defects in the cardiac muscle and ultimately die as a result of congestive heart failure. These data demonstrate a clear link between E2F3’s role in the proliferative capacity of the myocardium and cardiac function during both development and adulthood. PMID:19029823

King, Jennifer C.; Moskowitz, Ivan P. G.; Burgon, Patrick G.; Ahmad, Ferhaan; Stone, James R.; Seidman, Jonathan G.; Lees, Jacqueline A.

2009-01-01

211

Repression of androgen receptor transcription through the E2F1/DNMT1 axis.  

PubMed

Although androgen receptor (AR) function has been extensively studied, regulation of the AR gene itself has been much less characterized. In this study, we observed a dramatic reduction in the expression of androgen receptor mRNA and protein in hyperproliferative prostate epithelium of keratin 5 promoter driven E2F1 transgenic mice. To confirm an inhibitory function for E2F1 on AR transcription, we showed that E2F1 inhibited the transcription of endogenous AR mRNA, subsequent AR protein, and AR promoter activity in both human and mouse epithelial cells. E2F1 also inhibited androgen-stimulated activation of two AR target gene promoters. To elucidate the molecular mechanism of E2F-mediated inhibition of AR, we evaluated the effects of two functional E2F1 mutants on AR promoter activity and found that the transactivation domain appears to mediate E2F1 repression of the AR promoter. Because DNMT1 is a functional intermediate of E2F1 we examined DNMT1 function in AR repression. Repression of endogenous AR in normal human prostate epithelial cells was relieved by DNMT1 shRNA knock down. DNMT1 was shown to be physically associated within the AR minimal promoter located 22 bps from the transcription start site; however, methylation remained unchanged at the promoter regardless of DNMT1 expression. Taken together, our results suggest that DNMT1 operates either as a functional intermediary or in cooperation with E2F1 inhibiting AR gene expression in a methylation independent manner. PMID:21966451

Valdez, Conrad David; Davis, Joanne N; Odeh, Hana M; Layfield, Tristan L; Cousineau, Craig S; Berton, Thomas R; Johnson, David G; Wojno, Kirk J; Day, Mark L

2011-01-01

212

Materials characterization activities for %E2%80%9CTake Our Sons&Daughters to Work Day%E2%80%9D 2013.  

SciTech Connect

We created interactive demonstration activities for Take Our Daughters&Sons to Work Day (TODSTWD) 2013 in order to promote general interest in chemistry and also generate awareness of the type of work our laboratories can perform. %E2%80%9CCurious about Mars Rover Curiosity?%E2%80%9D performed an elemental analysis on rocks brought to our lab using the same technique utilized on the planet Mars by the NASA robotic explorer Curiosity. %E2%80%9CFood is Chemistry?%E2%80%9D utilized a mass spectrometer to measure, in seconds, each participant's breath in order to identify the food item consumed for the activity. A total of over 130 children participated in these activities over a 3 hour block, and feedback was positive. This document reports the materials (including handouts), experimental procedures, and lessons learned so that future demonstrations can benefit from the baseline work performed. We also present example results used to prepare the Food activity and example results collected during the Curiosity demo.

Mowry, Curtis Dale; Pimentel, Adam S.; Sparks, Elizabeth Schares; Hanlon, Brittany Paula

2013-09-01

213

B(E2) Evaluation for 01+?21+ Transitions in Even-Even Nuclei  

NASA Astrophysics Data System (ADS)

A collaborative study by Brookhaven-McMaster-Central Michigan is underway to evaluate B(E2)? for 01+?21+ transitions. This work is a continuation of a previous USNDP evaluation and has been motivated by a large number of recent measurements and nuclear theory developments. It includes an extended compilation, data evaluation procedures and shell model calculations. The subset of B(E2)? recommended values for nuclei of relevance to the double-beta decay problem is presented, and evaluation policies of experimental data and systematics are discussed. Future plans for completion of the B(E2;01+?21+) evaluation project are also described.

Pritychenko, B.; Birch, M.; Horoi, M.; Singh, B.

2014-06-01

214

v o l u m e 2 n o . 2 113 2011 International Mycological Association  

E-print Network

ARTICLE v o l u m e 2 · n o . 2 113 © 2011 International Mycological Association You are free the mycological community get ridofthelegacyofdualnomenclatureandArticle59without nomenclatural chaos? Two

215

40 CFR Figure E-2 to Subpart E of... - Product Manufacturing Checklist  

Code of Federal Regulations, 2010 CFR

... Protection of Environment 5 2010-07-01 2010-07-01 false Product Manufacturing Checklist E Figure E-2 to Subpart E of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

2010-07-01

216

The role of E2F4 in the growth suppressive properties of the retinoblastoma protein  

E-print Network

The growth suppressive functions of the retinoblastoma protein (pRB), the first identified tumor suppressor, are considerably mediated through the repression of the E2F transcription factors. Functional inactivation of ...

Lee, Eunice Y. (Eunice Yoon)

2005-01-01

217

E2F1 regulates p53R2 gene expression in p53-deficient cells.  

PubMed

The p53R2 gene encoding a small subunit of the ribonucleotide reductase has been identified as a p53-inducible gene. Although this gene is discovered as a target for p53 family proteins, the mechanism underlying p53R2 induction by DNA damage in p53-defiencient cells remains to be elucidated. In this study, we demonstrate that transcription factor E2F1 regulates the p53R2 gene expression in p53-deficient cells. We found that p53R2 was a target for E2F1 in DNA damage response (DDR), because ectopic expression of E2F1 in HCT116-p53(-/-) cells resulted in the increase of p53R2 mRNA and protein expression, and silencing E2F1 diminished its basic expression. Combination of luciferase reporter assay with overexpression or knockdown of E2F1 revealed that E2F1 directly activates the p53R2 gene. Chromatin immunoprecipitation (ChIP) assay showed E2F1 directly bound to the site (TTTGGCGG) at position -684 to -677 of the promoter under E2F1 overexpression or adriamycin (ADR) exposure. Moreover, silencing p53R2 could enhance apoptotic cell death in both HCT116-p53(-/-) and HCT116-p53(+/+) compared to ADR exposure, indicating that p53R2 may protect cancer cell from ADR-induced apoptosis. Together, we have identified a new role of E2F1 in the regulation of p53R2 expression in DDR, and silencing p53R2 may sensitize cancer cells to ADR-induced apoptosis. Our data support the notion that p53R2 is a potential target for cancer therapy. The involvement of E2F1-dependent p53R2 activation in DDR will provide further insight into the induction of p53R2 in p53-deficient cells. These data also give us a deeper understanding of E2F1 role in DDR. PMID:25312903

Qi, Jun-Juan; Liu, Ling; Cao, Ji-Xiang; An, Guo-Shun; Li, Shu-Yan; Li, Gang; Jia, Hong-Ti; Ni, Ju-Hua

2015-01-01

218

Mre11 Complex and DNA Replication: Linkage to E2F and Sites of DNA Synthesis  

Microsoft Academic Search

We show that the Mre11 complex associates with E2F family members via the Nbs1 N terminus. This asso- ciation and Nbs1 phosphorylation are correlated with S-phase checkpoint proficiency, whereas neither is suf- ficient individually for checkpoint activation. The Nbs1 E2F interaction occurred near the Epstein-Barr virus origin of replication as well as near a chromosomal replication origin in the c-myc

RICHARD S. MASER; OLGA K. MIRZOEVA; JULIE WELLS; HEIDI OLIVARES; BRET R. WILLIAMS; ROBERT A. ZINKEL; PEGGY J. FARNHAM; JOHN H. J. PETRINI

2001-01-01

219

p53 and E2F-1 Cooperate to Mediate Apoptosis  

Microsoft Academic Search

The tumor-suppressor protein p53 appears to function at the G_1 phase of the cell cycle as a checkpoint in response to DNA damage. Mutations in the p53 gene lead to an increased rate of genomic instability and tumorigenesis. The E2F-1 transcription factor is a protein partner of the retinoblastoma-susceptibility gene product, RB. E2F-1 appears to function as a positive regulator

Xiangwei Wu; Arnold J. Levine

1994-01-01

220

Regression of Human Papillomavirus Intraepithelial Lesions Is Induced by MVA E2 Therapeutic Vaccine.  

PubMed

Abstract Human papilloma viruses can induce warts, condylomas, and other intraepithelial cervical lesions that can progress to cancer. Cervical cancer is a serious problem in developing countries because early detection is difficult, and thus proper early treatment is many times missing. In this phase III clinical trial, we evaluated the potential use of MVA E2 recombinant vaccinia virus to treat intraepithelial lesions associated with papillomavirus infection. A total of 1176 female and 180 male patients with intraepithelial lesions were studied. They were injected with 10(7) MVA E2 virus particles directly into their uterus, urethra, vulva, or anus. Patients were monitored by colposcopy and cytology. Immune response was determined by measuring the antibody titer against MVA E2 virus and by analyzing the cytotoxic activity against cancer cells bearing papillomavirus DNA. Papillomavirus was determined by the Hybrid Capture method or by polymerase chain reaction analysis. By histology, 1051 (89.3%) female patients showed complete elimination of lesions after treatment with MVA E2. In 28 (2.4%) female patients, the lesion was reduced to CIN 1. Another 97 (8.3%) female patients presented isolated koilocytes after treatment. In men, all lesions were completely eliminated. All MVA E2-treated patients developed antibodies against the MVA E2 vaccine and generated a specific cytotoxic response against papilloma-transformed cells. Papillomavirus DNA was not detected after treatment in 83% of total patients treated. MVA E2 did not generate any apparent side effects. These data suggest that therapeutic vaccination with MVA E2 vaccine is an excellent candidate to stimulate the immune system and generate regression in intraepithelial lesions when applied locally. PMID:25275724

Rosales, Ricardo; López-Contreras, Mario; Rosales, Carlos; Magallanes-Molina, Jose-Roberto; Gonzalez-Vergara, Roberto; Arroyo-Cazarez, Jose Martin; Ricardez-Arenas, Antonio; Del Follo-Valencia, Armando; Padilla-Arriaga, Santiago; Guerrero, Miriam Veronica; Pirez, Miguel Angel; Arellano-Fiore, Claudia; Villarreal, Freddy

2014-12-01

221

Mitotic Kinesin-Like Protein 2 Binds and Colocalizes with Papillomavirus E2 during Mitosis  

Microsoft Academic Search

MKlp2 is a kinesin-like motor protein of the central mitotic spindle required for completion of cytokinesis. Papillomavirus E2 is a sequence specific DNA binding protein that regulates viral transcription and replica- tion and is responsible for partitioning viral episomes into daughter cells during cell division. We demonstrate that MKlp2 specifically associates with the E2 protein during mitosis. Using chromatin immunoprecipitation,

Ting Yu; Yu-Cai Peng; Elliot J. Androphy

2007-01-01

222

Noncanonical E2 Variant-Independent Function of UBC13 in Promoting Checkpoint Protein Assembly  

Microsoft Academic Search

The E2 ubiquitin-conjugating enzyme UBC13 plays pivotal roles in diverse biological processes. Recent studies have elucidated that UBC13, in concert with the E3 ubiquitin ligase RNF8, propagates the DNA damage signal via a ubiquitylation-dependent signaling pathway. However, mechanistically how UBC13 mediates its role in promoting checkpoint protein assembly and its genetic requirement for E2 variants remain elusive. Here we provide

Michael S. Y. Huen; Jun Huang; Jingsong Yuan; Masahiro Yamamoto; Shizuo Akira; Carolyn Ashley; Wei Xiao; Junjie Chen

2008-01-01

223

The E1-E2 center in gallium arsenide is the divacancy.  

PubMed

Based on defect energy levels computed from first-principles calculations, it is shown the E1-E2 center in irradiated GaAs cannot be due to an isolated arsenic vacancy. The only simple intrinsic defect with levels compatible with E1 and E2 is the divacancy. The arsenic monovacancy is reassigned to the E3 center in irradiated GaAs. These new assignments are shown to reconcile a number of seemingly contradictory experimental observations. PMID:25634829

Schultz, Peter A

2015-02-25

224

Distribution of E2 strength in 28Si below 50 MeV excitation energy  

Microsoft Academic Search

Inelastic electron scattering in 28Si between 4 and 50 MeV excitation energy reveals two concentrations of E2 strength in the continuum. One is between 15 and 20 MeV, with a peak at 17 MeV, and can be identified with the giant quadrupole resonance in the ground state oblate well. A broad distribution of E2 strength between 22 and 42 MeV

R. Pitthan; F. R. Buskirk; J. N. Dyer; E. E. Hunter; G. Pozinsky

1979-01-01

225

Activation of BPV-1 replication in vitro by the transcription factor E2  

NASA Astrophysics Data System (ADS)

Soluble extracts from uninfected murine cells supplemented with purified viral E1 and E2 proteins support the replication of exogenously added papilloma virus DNA. The E2 transactivator stimulates the binding of the E1 replication protein to the minimal origin of replication and activates DNA replication. These results support the concept that transcription factors have a direct role in the initiation of DNA replication in eukaryotes by participating in the assembly of a complex at the origin of replication.

Yang, Liu; Li, Rong; Mohr, Ian J.; Clark, Robin; Botchan, Michael R.

1991-10-01

226

Mitogenic Sonic hedgehog signaling drives E2F1-dependent lipogenesis in progenitor cells and Medulloblastoma  

PubMed Central

Deregulation of the Rb/E2F tumor suppressor complex and aberrantion of Sonic hedgehog (Shh) signaling are documented across the spectrum of human malignancies. Exaggerated de novo lipid synthesis is also found in certain highly proliferative, aggressive tumors. Here, we show that in Shh-driven medulloblastomas, Rb is inactivated and E2F1 is up-regulated, promoting lipogenesis. Extensive lipid accumulation and elevated levels of the lipogenic enzyme FASN mark those tumors. In primary cerebellar granule neuron precursors (CGNPs), proposed Shh-associated medulloblastoma cells-of-origin, Shh signaling triggers E2F1 and FASN expression while suppressing fatty acid oxidation (FAO), in a Smoothened-dependent manner. In the developing cerebellum, E2F1 and FASN co-localize in proliferating CGNPs. In vivo and in vitro, E2F1 is required for FASN expression and CGNP proliferation, and E2F1 knockdown impairs Shh-mediated FAO inhibition. Pharmacologic blockade of Rb inactivation and/or lipogenesis inhibits CGNP proliferation, drives medulloblastoma cell death, and extends survival of medulloblastoma-bearing animals in vivo. These findings identify a novel mechanism through which Shh signaling links cell cycle progression to lipid synthesis, through E2F1-dependent regulation of lipogenic enzymes. These findings pertinent to the etiology of tumor metabolism also underscore the key role of the Shh?E2F1?FASN axis in regulating de novo lipid synthesis in cancers, and as such its value as a global therapeutic target in hedgehog-dependent and/or Rb-inactivated tumors. PMID:20890301

Bhatia, Bobby; Hsieh, Michael; Kenney, Anna Marie; Nahlé, Zaher

2010-01-01

227

Mitogenic Sonic hedgehog signaling drives E2F1-dependent lipogenesis in progenitor cells and medulloblastoma  

Microsoft Academic Search

Deregulation of the Rb\\/E2F tumor suppressor complex and aberrantion of Sonic hedgehog (Shh) signaling are documented across the spectrum of human malignancies. Exaggerated de novo lipid synthesis is also found in certain highly proliferative, aggressive tumors. Here, we show that in Shh-driven medulloblastomas, Rb is inactivated and E2F1 is upregulated, promoting lipogenesis. Extensive lipid accumulation and elevated levels of the

B Bhatia; M Hsieh; A M Kenney; Z Nahlé

2011-01-01

228

Sequence Determinants of E2-E6AP Binding Affinity and Specificity  

PubMed Central

The conjugation of ubiquitin to substrates requires a series of enzymatic reactions consisting of an activating enzyme (E1), conjugating enzymes (E2) and ligases (E3). Tagging the appropriate substrate with ubiquitin is achieved by specific E2-E3 and E3-substrate interactions. E6AP, a member of the HECT family of E3s, has been previously shown to bind and function with the E2s UbcH7 and UbcH8. To decipher the sequence determinants of this specificity we have developed a quantitative E2-E3 binding assay based on fluorescence polarization and used this assay to measure the affinity of wild type and mutant E2–E6AP interactions. Alanine scanning of the E6AP–UbcH7 binding interface identified 4 side chains on UbcH7 and 6 side chains on E6AP that contribute more than 1 kcal /mol to the binding free energy. Two of the hot spot residues from UbcH7 (K96 and K100) are conserved in UbcH8 but vary across other E2s. To determine if these are key specificity determining residues, we attempted to induce a tighter association between the E2 UbcH5b and E6AP by mutating the corresponding positions in UbcH5b to lysines. Surprisingly, the mutations had little effect, but rather a mutation at UbcH7 position 4, which is not at a hot spot on the UbcH7–E6AP interface, significantly strengthened UbcH5bs affinity for E6AP. This result indicates that E2-E3 binding specificities are a function of both favorable interactions that promote binding, and unfavorable interactions that prevent binding with unwanted partners. PMID:17433363

Eletr, Ziad M; Kuhlman, Brian

2007-01-01

229

Analysis of the papillomavirus E2 and bromodomain protein Brd4 interaction using bimolecular fluorescence complementation.  

PubMed

The human papillomavirus (HPV) vaccines effectively protect against new infections of up to four HPV subtypes. However, these vaccines are not protective against many other clinically relevant HPV subtypes and are ineffective at treating established HPV infections. There is therefore a significant need for antiviral treatments for persistent HPV infections. A promising anti-HPV drug target is the interaction between the HPV E2 protein and cellular bromodomain-containing protein 4 (Brd4) since this protein complex mediates several processes important for the viral life cycle including viral genome maintenance, replication, and transcription. Using bimolecular fluorescence complementation (BiFC) technology, we demonstrate the E2 and Brd4 interaction on both interphase chromatin and mitotic chromosomes throughout mitosis. The E2-Brd4 BiFC was significantly diminished by mutating the Brd4 binding sites in E2 or by a dominant negative inhibitor of the E2-Brd4 interaction, demonstrating the potential of BiFC for identifying inhibitors of this important virus-host interaction. Importantly, when Brd4 was released from chromatin using the bromodomain inhibitor JQ1(+), the E2-Brd4 interacting complex relocated into foci that no longer associate with mitotic chromosomes, pointing to JQ1(+) as a promising antiviral inhibitor of HPV genome maintenance during HPV persistent infection. PMID:24205059

Helfer, Christine M; Wang, Ranran; You, Jianxin

2013-01-01

230

The HPV E2-Host Protein-Protein Interactions: A Complex Hijacking of the Cellular Network  

PubMed Central

Over 100 genotypes of human papillomaviruses (HPVs) have been identified as being responsible for unapparent infections or for lesions ranging from benign skin or genital warts to cancer. The pathogenesis of HPV results from complex relationships between viral and host factors, driven in particular by the interplay between the host proteome and the early viral proteins. The E2 protein regulates the transcription, the replication as well as the mitotic segregation of the viral genome through the recruitment of host cell factors to the HPV regulatory region. It is thereby a pivotal factor for the productive viral life cycle and for viral persistence, a major risk factor for cancer development. In addition, the E2 proteins have been shown to engage numerous interactions through which they play important roles in modulating the host cell. Such E2 activities are probably contributing to create cell conditions appropriate for the successive stages of the viral life cycle, and some of these activities have been demonstrated only for the oncogenic high-risk HPV. The recent mapping of E2-host protein-protein interactions with 12 genotypes representative of HPV diversity has shed some light on the large complexity of the host cell hijacking and on its diversity according to viral genotypes. This article reviews the functions of E2 as they emerge from the E2/host proteome interplay, taking into account the large-scale comparative interactomic study. PMID:23341853

Muller, Mandy; Demeret, Caroline

2012-01-01

231

Identification of Aptamer-Binding Sites in Hepatitis C Virus Envelope Glycoprotein E2  

PubMed Central

Hepatitis C Virus (HCV) encodes two envelope glycoproteins, E1 and E2. Our previous work selected a specific aptamer ZE2, which could bind to E2 with high affinity, with a great potential for developing new molecular probes as an early diagnostic reagents or therapeutic drugs targeting HCV. In this study, the binding sites between E2 and aptamer ZE2 were further explored. E2 was truncated to 15 peptides (P1 to P15) and these peptides were used to detect the affinity with ZE2 by ELISA respectively. The peptide with high affinity was then further truncated, detected and compared with six kinds of HCV genotypes. The basic amino acid in 500 aa bound to ZE2 with high affinity, while acidic amino acid in 501 aa reduced the reaction between E2 and ZE2. The results showed the 500 aa and 501 aa of E2 were the key sites that bound to ZE2. PMID:25648186

Chen, Fan; Chen, Si-Chong; Zhou, Jing; Chen, Zhi-De; Chen, Fang

2015-01-01

232

Enhancers and trans-acting E2 transcriptional factors of papillomaviruses.  

PubMed Central

The upstream regulatory regions of human papillomavirus (HPV) types 1, 6b, 7, 11, 16, and 18, bovine papillomavirus type 1, and cottontail rabbit papillomavirus were cloned into transcriptional enhancer assay plasmids which carry the simian virus 40 early promoter lacking its own enhancer and the bacterial gene encoding chloramphenicol acetyltransferase (EC 2.3.1.28) (CAT). Enhancer activity, reflected by CAT gene expression, was detected in all of the upstream regulatory regions tested only when the recombinants were cotransfected with plasmids which express an intact E2 open reading frame of HPV types 1 and 11 or bovine papillomavirus type 1. Each E2 protein stimulated the enhancer from the same virus and, to somewhat lesser degrees, also those from the heterologous viruses. Hence, the enhancer and the E2 protein are functionally conserved among papillomaviruses. There was some nonreciprocity in the extent of trans-activation in heterologous E2-enhancer interactions. Primer extension analyses demonstrated that the E2 proteins increased the abundance of CAT gene mRNA. Tandem multiplication of the HPV type 11 enhancer sequence dramatically increased its response to E2 stimulation; this is possibly relevant to the pathogenicity of papillomaviruses. Images PMID:3037119

Hirochika, H; Broker, T R; Chow, L T

1987-01-01

233

Molecular Links between the E2 Envelope Glycoprotein and Nucleocapsid Core in Sindbis Virus  

PubMed Central

A three-dimensional reconstruction of Sindbis virus at 7.0 Å resolution presented here provides a detailed view of the virion structure and includes structural evidence for key interactions that occur between the capsid protein (CP) and transmembrane (TM) glycoproteins E1 and E2. Based on crystal structures of component proteins and homology modeling, we constructed a nearly complete, pseudo-atomic model of the virus. Notably, this includes identification of the 33-residue cytoplasmic domain of E2 (cdE2), which follows a path from the E2 TM helix to the CP where it enters and exits the CP hydrophobic pocket and then folds back to contact the viral membrane. Modeling analysis identified three major contact regions between cdE2 and CP, and the roles of specific residues were probed by molecular genetics. This identified R393 and E395 of cdE2 and Y162 and K252 of CP as critical for virus assembly. The N-termini of the CPs form a contiguous network that interconnects 12 pentameric and 30 hexameric CP capsomers. A single glycoprotein spike cross-links three neighboring CP capsomers as might occur during initiation of virus budding. PMID:22001018

Tang, Jinghua; Jose, Joyce; Chipman, Paul; Zhang, Wei; Kuhn, Richard J.; Baker, Timothy S.

2012-01-01

234

Regulation of the vascular endothelial growth factor (VEGF) receptor Flk-1/KDR by estradiol through VEGF in uterus.  

PubMed

The induction of vascular endothelial growth factor (VEGF) expression by 17beta-estradiol (E(2)) in many target cells, including epithelial cells, fibroblasts and smooth muscle cells, suggests a role for this hormone in the modulation of angiogenesis and vascular permeability. We have already described a cyclic increase in Flk-1/KDR-expressing capillaries in the human endometrium during the proliferative and mid-secretory phases, strongly suggestive of an E(2) effect on Flk-1/KDR expression in the endometrial capillaries. However, it is unclear whether these processes are due to a direct effect of E(2) on endothelial cells. Using immunohistochemistry, we report an increase in Flk-1/KDR expression in endometrial capillaries of ovariectomized mice treated with E(2), or both E(2) and progesterone. This process is mediated through estrogen receptor (ER) activation. In vitro experiments using quantitative RT-PCR analysis demonstrate that Flk-1/KDR expression was not regulated by E(2) in human endothelial cells from the microcirculation (HMEC-1) or macrocirculation (HUVEC), even in endothelial cells overexpressing ERalpha or ERbeta after ER-mediated adenovirus infection. In contrast, Flk-1/KDR expression was up-regulated by VEGF itself, in a time- and dose-dependent manner, with the maximal response at 10 ng/ml. Thus, we suggest that E(2) up-regulates Flk-1/KDR expression in vivo in endothelial cells mainly through the modulation of VEGF by a paracrine mechanism. It is currently unknown whether or not the endothelial origin might account for differences in the E(2)-modulation of VEGF receptor expression, particularly in relation to the vascular bed of sex steroid-responsive tissues. PMID:16394178

Hervé, M A J; Meduri, G; Petit, F G; Domet, T S; Lazennec, G; Mourah, S; Perrot-Applanat, M

2006-01-01

235

The effects of a constitutive expression of transforming growth factor-alpha on the growth of MCF-7 human breast cancer cells in vitro and in vivo.  

PubMed

It has been suggested that transforming growth factor-alpha (TGF-alpha) is a mitogenic autocrine growth factor for human breast cancer cells, responsible for mediating the mitogenic effects of 17 beta-estradiol (E2) in responsive cells. To test this hypothesis we have introduced eukaryotic expression vectors directing the expression of TGF-alpha mRNA into E2-responsive MCF-7 human breast cancer cells. Transfected cells produce levels of TGF-alpha equivalent to or greater than those produced by both E2-stimulated MCF-7 cells and hormone-independent MDA-MB-231 cells. One transfected clone (H8) secretes sufficient TGF-alpha to fully down-regulate EGF-R expression. However, both of the transfected clones that constitutively secrete elevated levels of TGF-alpha (A8 and H8) respond to E2 stimulation in vitro by increasing the rate of cellular proliferation and inducing PGR synthesis. The basal proliferative capacity of H8 and A8 cells is equivalent to that of the parental cells and to cells transfected only with the G418 (neomycin) resistance gene. Furthermore, the TGF-alpha cDNA-transfected clones do not form tumors in ovariectomized athymic nude mice without E2 supplementation. Thus, the precise role of TGF-alpha in mediating either the in vivo or the in vitro mitogenic effects of E2 in MCF-7 human breast cancer cells remains unclear. While TGF-alpha expression may be essential, it is not sufficient alone to induce the fully E2-independent phenotype. Thus, TGF-alpha may function in combination with other E2-induced growth factors to control breast cancer proliferation and tumorigenesis. PMID:2710138

Clarke, R; Brünner, N; Katz, D; Glanz, P; Dickson, R B; Lippman, M E; Kern, F G

1989-02-01

236

Venous thrombosis and changes of hemostatic variables during cross-sex hormone treatment in transsexual people.  

PubMed

The incidence of venous thrombosis associated with estrogen treatment in male-to-female (M-->F) transsexuals is considerably higher with administration of oral ethinyl estradiol (EE) than with transdermal (td) 17-beta-estradiol (E(2)). To find an explanation for the different thrombotic risks of oral EE and td E(2) use, we compared the effects of treatment of M-->F transsexuals with cyproterone acetate (CPA) only, and with CPA in combination with td E(2), oral EE, or oral E(2) on a number of hemostatic variables [activated protein C (APC) resistance and plasma levels of protein S, protein C, and prothombin], all of which are documented risk factors for venous thrombosis. APC resistance was determined by quantification of the effect of APC on the amount of thrombin generated during tissue factor-initiated coagulation; plasma levels of total and free protein S were determined by standard ELISA; and levels of prothrombin and protein C were determined with functional assays after complete activation of the zymogens with specific snake venom proteases. CPA-only, td-E(2)+CPA, or oral-E(2)+CPA treatment produced rather small effects on hemostatic variables, whereas oral EE treatment resulted in a large increase in APC resistance from 1.2 +/- 0.8 to 4.1 +/- 1 (P < 0.001), a moderate increase in plasma protein C (9%; P = 0.012), and a large decrease in both total and free plasma protein S (30%; P < 0.005). The large differential effect of oral EE and oral E(2) indicates that the prothrombotic effect of EE is due to its molecular structure rather than to a first-pass liver effect (which they share). Moreover, these differences may explain why M-->F transsexuals treated with oral EE are exposed to a higher thrombotic risk than transsexuals treated with td E(2). Testosterone administration to female-to-male transsexuals had an antithrombotic effect. PMID:14671159

Toorians, A W F T; Thomassen, M C L G D; Zweegman, S; Magdeleyns, E J P; Tans, G; Gooren, L J G; Rosing, J

2003-12-01

237

Effect of photoperiod on endocrine profiles and vitellogenin expression in European eels Anguilla anguilla during artificially induced ovarian development.  

PubMed

The aim of this work was to determine the effects of dark and light conditions on the E2, testosterone and thyroid hormones levels and on the gene expression levels (vitellogenin 1, vitellogenin 2, and estradiol receptor one) in European eels (Anguilla anguilla) during ovarian development induced by increasing doses of carp pituitary extracts (CPEs). The subjects were divided into 2 groups: 14-hour light:10-hour dark (Light Group) and 24-hour darkness (Dark Group). All the eels received intramuscular injections with CPE at a dosage of 10 mg/kg body weight (BW) once a week for the first 3 weeks, 20 mg/kg BW fourth-sixth week, 30 mg/kg BW seventh-ninth week, and 40 mg/kg up to the end of the experiment (13th week). Vitellogenin and estradiol receptor expression levels did not show significant differences between the two housing conditions whereas in both groups vitellogenin mRNA increased starting from first CPE injection. Testosterone and 17-beta estradiol plasma levels were significantly greater in the Dark Group compared with the Light Group starting from the ninth and the 13th week, respectively. These results suggest that darkness could be a useful variable for standardizing gonadal maturation in eels kept in captivity. PMID:25459031

Parmeggiani, A; Govoni, N; Zannoni, A; Di Biase, A; Sirri, R; Forni, M; Mandelli, M; Mordenti, O

2015-03-01

238

Development of in vivo and in vitro assays to evaluate the physiological effects of environmental estrogens in fish  

SciTech Connect

There are many reports of environmental chemicals that may act as estrogens by binding to the nuclear 17-{beta} estradiol (E{sub 2}) receptor. Experiments were conducted to evaluate whether the plant sterol {beta}-sitosterol and the detergent nonylphenol interact with hepatic estrogen receptors in fish. These compounds are estrogenic in mammals and are found in treated industrial and municipal sewage waters and in pulp and paper mill effluents. Specific high affinity binding sites were characterized in rainbow trout. Nonylphenol and sitosterol were found to have relative affinities of 0.009 and 0.0001 compared to E{sub 2}. To determine if these compounds act as E{sub 2} agonists, their ability to induce estrogen dependent processes was monitored. Induction of estrogen receptors is a common E{sub 2} dependent effect. While other groups have shown in other systems that induction of hepatic E2 receptor levels was estrogen dependent, the authors found that E{sub 2} did not increase E{sub 2} binding in goldfish. However, using isolated goldfish hepatocytes cells, E{sub 2}, sitosterol and nonylphenol induced vitellogenin production. Current studies are aimed at evaluating the structure and activity relationships of these compounds responsible for causing E{sub 2} binding and vitellogenin inductions. Other means to evaluate E{sub 2} binding in goldfish liver are also being investigated.

Tremblay, L.; Yao, Z.; Kraak, G. Van Der [Univ. of Guelph, Ontario (Canada). Dept. of Zoology

1995-12-31

239

Hyaluronic acid prevents immunosuppressive drug-induced ovarian damage via up-regulating PGRMC1 expression  

PubMed Central

Chemotherapy treatment in women can frequently cause damage to the ovaries, which may lead to primary ovarian insufficiency (POI). In this study, we assessed the preventative effects of hyaluronic acid (HA) in immunosuppressive drug-induced POI-like rat models and investigated the possible mechanisms. We found that HA, which was reduced in primary and immunosuppressant-induced POI patients, could protect the immunosuppressant-induced damage to granulosa cells (GCs) in vitro. Then we found that HA blocked the tripterygium glycosides (TG) induced POI-like presentations in rats, including delayed or irregular estrous cycles, reduced 17 beta-estradiol(E2) concentration, decreased number of follicles, destruction of follicle structure, and damage of reproductive ability. Furthermore, we investigated the mechanisms of HA prevention effects on POI, which was associated with promotion of GC proliferation and PGRMC1 expression. In conclusion, HA prevents chemotherapy-induced ovarian damage by promoting PGRMC1 in GCs. This study may provide a new strategy for prevention and treatment of POI. PMID:25558795

Zhao, Guangfeng; Yan, Guijun; Cheng, Jie; Zhou, Xue; Fang, Ting; Sun, Haixiang; Hou, Yayi; Hu, Yali

2015-01-01

240

Plasma androgen correlation, EROD induction, reduced condition factor, and the occurrence of organochlorine pollutants in reproductively immature white sturgeon (Acipenser transmontanus) from the Columbia River, USA.  

PubMed

White sturgeon (Acipenser transmontanus) support an active fishery in the Columbia River, but there is poor reproductive success within the impounded sections. The poor reproductive success has been attributed to hydroelectric development; however, water pollution could be a significant factor. White sturgeon plasma, liver, and gonad samples were collected from four Columbia River locations and a California aquaculture facility. Total length and weight of the fish were measured, and plasma samples were analyzed for testosterone (T), 11-ketotestosterone (KT), 17 beta-estradiol (E2), and vitellogenin. Liver samples were analyzed for chlorinated pesticides and polychlorinated biphenyls, ethoxyresorufin-O-deethylase (EROD) activity and histopathology. Gonads were examined histologically to assess sexual maturity and characterize any lesions. Significant differences by location existed for p,p'-DDE, EROD activity, and condition factor. Plasma T was negatively correlated with p,p'-DDE in males and females, and plasma KT was negatively correlated in males. These data indicate that pollutants could be adversely affecting white sturgeon in the Columbia River basin. PMID:11462142

Foster, E P; Fitzpatrick, M S; Feist, G W; Schreck, C B; Yates, J; Spitsbergen, J M; Heidel, J R

2001-08-01

241

Sex hormones and neuropathology in elderly men: the HAAS.  

PubMed

Experimental studies suggest 17-beta estradiol (E2) and testosterone (T) may have neuroprotective properties that are associated with Alzheimer's and vascular pathology. However, there are limited studies correlating steroid hormones with autopsy findings in humans. In this community-based autopsy study of elderly men (n=232) participating in the Honolulu Asia Aging Study, we found a significant decrease of neurofibrillary tangles in the highest tertile of free serum estradiol [IRR=0.43 (0.3-0.7)] after controlling for age at blood draw, interval from blood draw until death, ApoE allele, and socio-demographic health factors. Higher Free-T levels were associated with a two-fold increased risk for micro infarcts [IRR=2.2; 95% CI (1.2-4.1)]. There was no association between sex hormones and amyloid plaques or cerebral amyloid angiopathy. This community-based autopsy study suggests that peripheral levels of sex hormones are associated with neurofibrillary tangles and micro-infarcts, but not with other neuropathologic markers of brain disease in elderly men. PMID:16500732

Strozyk, Dorothea; White, Lon R; Petrovitch, Helen; Geerlings, Mirjam I; Remaley, Alan T; Launer, Lenore J

2007-01-01

242

Phenolic A ring requirement for the neuroprotective effects of steroids.  

PubMed

Estrogens are reported to reduce the incidence of Alzheimer's disease and 17beta-estradiol (betaE2), the potent, naturally occurring estrogen, exerts neuroprotective effects in a variety of in vivo and in vitro model systems. The present study elucidates the structural requirements of steroids and related compounds for neuroprotectivity at low nM doses. All estrogens tested with an intact phenolic A ring protected SK-N-SH neuroblastoma cells from the toxic effects of serum-deprivation. All 3-O-methyl ether cogeners tested were inactive indicating the importance of a phenolic A ring. The diphenolic estrogen mimic diethylstilbesterol (DES) was neuroprotective and retention of a single phenolic function was sufficient to retain neuroprotective activity. The di-O-methyl ether of DES was inactive. The following steroids which lack a phenolic A ring were also inactive: testosterone; dihydrotestosterone; progesterone; corticosterone; prednisolone; 6 alpha-methylprednisolone; aldosterone; and cholesterol. Finally, phenol, lipophilic phenols, and tetrahydronapthol were inactive. These results suggest that a phenolic A ring and at least three rings of the steroid nucleus are necessary for the neuroprotective activity of estrogens. PMID:9459189

Green, P S; Gordon, K; Simpkins, J W

1997-01-01

243

Structure-function analysis of hepatitis C virus envelope glycoproteins E1 and E2.  

PubMed

Hepatitis C virus (HCV) is the leading cause of chronic liver disease in humans. The envelope proteins of HCV are potential candidates for vaccine development. The absence of three-dimensional (3D) structures for the functional domain of HCV envelope proteins [E1.E2] monomer complex has hindered overall understanding of the virus infection, and also structure-based drug design initiatives. In this study, we report a 3D model containing both E1 and E2 proteins of HCV using the recently published structure of the core domain of HCV E2 and the functional part of E1, and investigate immunogenic implications of the model. HCV [E1.E2] molecule is modeled by using aa205-319 of E1 to aa421-716 of E2. Published experimental data were used to further refine the [E1.E2] model. Based on the model, we predict 77 exposed residues and several antigenic sites within the [E1.E2] that could serve as vaccine epitopes. This study identifies eight peptides which have antigenic propensity and have two or more sequentially exposed amino acids and 12 singular sites are under negative selection pressure that can serve as vaccine or therapeutic targets. Our special interest is 285FLVGQLFTFSPRRHW299 which has five negatively selected sites (L286, V287, G288, T292, and G303) with three of them sequential and four amino acids exposed (F285, L286, T292, and R296). This peptide in the E1 protein maps to dengue envelope vaccine target identified previously by our group. Our model provides for the first time an overall view of both the HCV envelope proteins thereby allowing researchers explore structure-based drug design approaches. PMID:25245635

Nayak, Aparajita; Pattabiraman, Nagarajan; Fadra, Numrah; Goldman, Radoslav; Kosakovsky Pond, Sergei L; Mazumder, Raja

2014-10-15

244

Prenatal in vivo bulbourethral gland development is not affected by prostaglandin E2 inhibition.  

PubMed

Investigation of bulbourethral gland (BUG) development is useful to study genitourinary (GU) tract growth and differentiation. Understanding GU tract growth and differentiation is relevant to testing the hypothesis that the initial lesion of human benign prostatic hyperplasia involves focal re-expression of inductive processes in the periurethral region of the prostatic transitional zone. Prostaglandins play a role in regulating growth and morphogenesis of different organ systems. Previous reports have proposed that prostaglandin E2 (PgE2) mediates the masculinizing effects of testosterone in the developing neonatal male GU tract. We have previously shown that androgens lower rather than raise BUG PgE2 levels. Further studies led us to conclude that PgE2 does not play a major role in postnatal BUG growth and morphogenesis in vitro. In order to investigate the possible role of PgE2 in prenatal BUG development, indomethacin (INDO, 1.0 mg/kg- day, subcutaneously) was administered to pregnant BALB/c mice on gestational days 12-18. Control pregnant mice were either untreated or injected with dimethylsulfoxide vehicle. Anogenital distances were measured within 12 hours after birth in male and female offspring on day 19. In male neonatal mice, BUGs were examined histologically and PgE2 levels were measured by radioimmunoassay in BUGs and whole genital tracts. We observed no significant morphological differences in INDO-exposed BUGs compared to controls. No significant differences in mean anogenital distances of INDO-exposed male offspring or controls were detected. Mean anogenital distances of female offspring were similar in the three respective groups. Mean BUG PgE2 levels in INDO-exposed neonates were significantly lower (P < 0.05) than in untreated neonates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7768753

Little, J S; Goode, R L; Neubauer, B L

1995-01-01

245

Usability of Fag e 2 ImmunoCAP in the diagnosis of buckwheat allergy.  

PubMed

Currently, the detection of crude buckwheat extract-specific IgE by ImmunoCAP (f11) (Phadia AB, Uppsala, Sweden) is widely used to diagnose buckwheat allergy. However, the results of this test do not always correlate with the development of allergic symptoms. This study aimed to evaluate the diagnostic usefulness of specific IgE antibody titers for the major buckwheat allergens Fag e 1 and Fag e 2. Specific IgE antibodies were determined using the ImmunoCAP method for native Fag e 1 and Fag e 2, recombinant Fag e 1 and Fag e 2, and crude buckwheat extract (f11) in 10 buckwheat allergy patients, 14 atopic dermatitis patients, and 15 healthy subjects. All buckwheat allergy patients showed positive results for native Fag e 1- and Fag e 2-specific IgE tests and for ImmunoCAP (f11). In contrast, the rates of atopic dermatitis patients with positive results for native Fag e 1- and Fag e 2-specific IgE tests were 64.2% (9/14) and 57.1% (8/14), respectively. The sensitivities of the test using recombinant proteins were lower than those of the test using native proteins. The area under the curve (AUC) as determined by receiver operating characteristic (ROC) curve analysis was the largest for the native Fag e 2-specific IgE test (0.967), with a sensitivity of 90% and a specificity of 89.6% (cut-off: 2.74 kUa/L). Thus, the native Fag e 2-specific IgE antibody titer obtained using the ImmunoCAP method is more reliable than the buckwheat ImmunoCAP (f11) value for predicting buckwheat allergy. PMID:21461893

Tohgi, Kimiko; Kohno, Kunie; Takahashi, Hitoshi; Matsuo, Hiroaki; Nakayama, Satoshi; Morita, Eishin

2011-11-01

246

The Viral E8^E2C Repressor Limits Productive Replication of Human Papillomavirus 16  

PubMed Central

Productive replication of human papillomavirus type 16 (HPV16) occurs only in differentiated keratinocyte cells. In addition to the viral E2 activator protein, HPV16 and related HPV types express transcripts coding for an E8^E2C fusion protein, which limits genome replication in undifferentiated keratinocytes. To address E8^E2C's role in productive replication of HPV16, stable keratinocyte cell lines containing wild-type (wt), E8^E2C knockout (E8?), or E8 KWK mutant (mt) genomes, in which conserved E8 residues were inactivated, were established. Copy numbers of E8? and E8 KWK mt genomes and amounts of early and late viral transcripts were greatly increased compared to those for the wt in undifferentiated keratinocytes, suggesting that HPV16 E8^E2C activities are highly dependent upon the E8 part. Upon differentiation in organotypic cultures, E8 mt genomes displayed higher early viral transcript levels, but no changes in cellular differentiation or virus-induced cellular DNA replication in suprabasal cells were observed. E8 mt genomes were amplified to higher copy numbers and showed increased L1 transcripts compared to wt genomes. Furthermore, the number of cells expressing the viral late protein E4 or L1 or amplifying viral genomes was greatly increased in E8 mt cell lines. In wild-type cells, E8^E2C transcript levels did not decrease by differentiation. Our data indicate that the E8^E2C repressor limits viral transcription and replication throughout the complete life cycle of HPV16. PMID:24198405

Straub, Elke; Dreer, Marcel; Fertey, Jasmin; Iftner, Thomas

2014-01-01

247

Knockdown of E2F2 inhibits tumorigenicity, but preserves stemness of human embryonic stem cells.  

PubMed

Tumorigenicity of human pluripotent stem cells is a major threat limiting their application in cell therapy protocols. It remains unclear, however, whether suppression of tumorigenic potential can be achieved without critically affecting pluripotency. A previous study has identified hyperexpressed genes in cancer stem cells, among which is E2F2, a gene involved in malignant transformation and stem cell self-renewal. Here we tested whether E2F2 knockdown would affect the proliferative capacity and tumorigenicity of human embryonic stem cells (hESC). Transient E2F2 silencing in hESC significantly inhibited expression of the proto-oncogenes BMI1 and HMGA1, in addition to proliferation of hESC, indicated by a higher proportion of cells in G1, fewer cells in G2/M phase, and a reduced capacity to generate hESC colonies in vitro. Nonetheless, E2F2-silenced cells kept expression of typical pluripotency markers and displayed differentiation capacity in vitro. More importantly, E2F2 knockdown in hESC significantly inhibited tumor growth in vivo, which was considerably smaller than tumors generated from control hESC, although displaying typical teratoma traits, a major indicator of pluripotency retention in E2F2-silenced cells. These results suggest that E2F2 knockdown can inhibit hESC proliferation and tumorigenicity without significantly harming stemness, providing a rationale to future protocols aiming at minimizing risks related to therapeutic application of cells and/or products derived from human pluripotent cells. PMID:24446828

Suzuki, Daniela Emi; Nakahata, Adriana Miti; Okamoto, Oswaldo Keith

2014-06-01

248

77 FR 21782 - International Conference on Harmonisation; Draft Guidance for Industry on E2C(R2) Periodic...  

Federal Register 2010, 2011, 2012, 2013

...guidances, ``E2C Clinical Safety Data Management: Periodic Safety Update...Addendum to E2C Clinical Safety Data Management: Periodic Safety Update...regulatory authorities, automated data mining techniques, more attention to...

2012-04-11

249

Membrane-initiated actions of estradiol (E2) in the regulation of LH secretion in ovariectomized (OVX) ewes  

PubMed Central

Background We demonstrated that E2 conjugated to BSA (E2BSA) induces a rapid membrane-initiated inhibition of LH secretion followed hours later by a slight increase in LH secretion. Whether these actions of E2BSA are restricted to the pituitary gland and whether the membrane-initiated pathway of E2BSA contributes to the up-regulation of the number of GnRH receptors during the positive feedback effect of E2 were evaluated here. We have shown that the suppression of LH secretion induced by E2 and E2BSA is the result of a decreased responsiveness of the pituitary gland to GnRH. In this study we further tested the ability of E2BSA to decrease the responsiveness of the pituitary gland to GnRH under the paradigm of the preovulatory surge of LH induced by E2. Methods For the first experiment GnRH and LH secretions were determined in samples of pituitary portal and jugular blood, respectively, in ewes treated with 12 mg E2BSA. In the second experiment, the number of GnRH receptors was quantified in ewes 12 h after administration of 25 micrograms E2 (the expected time for the increase in the number of GnRH receptors and the positive feedback effect of E2 in LH secretion) or 12 mg E2BSA. In the third experiment, the preovulatory-like surge of LH was characterized in ewes injected with 25 micrograms E2 alone or followed 8 h later (before the beginning of the LH surge) with 60 mg E2BSA. Results a) the decrease in LH secretion induced by E2BSA was not accompanied by changes in the pulsatile pattern of GnRH, b) E2BSA increased the number of GnRH receptors, and c) the presence of E2BSA in E2-treated ewes delayed the onset, reduced the length, and decreased the amount of LH released during the preovulatory surge of LH. Conclusions a) the rapid suppression of LH secretion induced by E2BSA is mediated only via a direct action on the pituitary gland, b) E2 acting via a membrane-initiated pathway contributes to increase the number of GnRH receptors and, c) administration of E2BSA near the beginning of the pre-ovulatory surge of LH delays and reduces the magnitude of the surge. PMID:20459750

2010-01-01

250

Interaction of the Papillomavirus E8?E2C Protein with the Cellular CHD6 Protein Contributes to Transcriptional Repression? †  

PubMed Central

Expression of the E6 and E7 oncogenes of high-risk human papillomaviruses (HPV) is controlled by cellular transcription factors and by viral E2 and E8?E2C proteins, which are both derived from the HPV E2 gene. Both proteins bind to and repress the HPV E6/E7 promoter. Promoter inhibition has been suggested to be due to binding site competition with cellular transcription factors and to interactions of different cellular transcription modulators with the different amino termini of E2 and E8?E2C. We have now identified the cellular chromodomain helicase DNA binding domain 6 protein (CHD6) as a novel interactor with HPV31 E8?E2C by using yeast two-hybrid screening. Pull-down and coimmunoprecipitation assays indicate that CHD6 interacts with the HPV31 E8?E2C protein via the E2C domain. This interaction is conserved, as it occurs also with the E8?E2C proteins expressed by HPV16 and -18 and with the HPV31 E2 protein. Both RNA knockdown experiments and mutational analyses of the E2C domain suggest that binding of CHD6 to E8?E2C contributes to the transcriptional repression of the HPV E6/E7 oncogene promoter. We provide evidence that CHD6 is also involved in transcriptional repression but not activation by E2. Taken together our results indicate that the E2C domain not only mediates specific DNA binding but also has an additional role in transcriptional repression by recruitment of the CHD6 protein. This suggests that repression of the E6/E7 promoter by E2 and E8?E2C involves multiple interactions with host cell proteins through different protein domains. PMID:20631145

Fertey, Jasmin; Ammermann, Ingo; Winkler, Michael; Stöger, Reinhard; Iftner, Thomas; Stubenrauch, Frank

2010-01-01

251

Interaction of the papillomavirus E8--E2C protein with the cellular CHD6 protein contributes to transcriptional repression.  

PubMed

Expression of the E6 and E7 oncogenes of high-risk human papillomaviruses (HPV) is controlled by cellular transcription factors and by viral E2 and E8--E2C proteins, which are both derived from the HPV E2 gene. Both proteins bind to and repress the HPV E6/E7 promoter. Promoter inhibition has been suggested to be due to binding site competition with cellular transcription factors and to interactions of different cellular transcription modulators with the different amino termini of E2 and E8--E2C. We have now identified the cellular chromodomain helicase DNA binding domain 6 protein (CHD6) as a novel interactor with HPV31 E8--E2C by using yeast two-hybrid screening. Pull-down and coimmunoprecipitation assays indicate that CHD6 interacts with the HPV31 E8--E2C protein via the E2C domain. This interaction is conserved, as it occurs also with the E8--E2C proteins expressed by HPV16 and -18 and with the HPV31 E2 protein. Both RNA knockdown experiments and mutational analyses of the E2C domain suggest that binding of CHD6 to E8--E2C contributes to the transcriptional repression of the HPV E6/E7 oncogene promoter. We provide evidence that CHD6 is also involved in transcriptional repression but not activation by E2. Taken together our results indicate that the E2C domain not only mediates specific DNA binding but also has an additional role in transcriptional repression by recruitment of the CHD6 protein. This suggests that repression of the E6/E7 promoter by E2 and E8--E2C involves multiple interactions with host cell proteins through different protein domains. PMID:20631145

Fertey, Jasmin; Ammermann, Ingo; Winkler, Michael; Stöger, Reinhard; Iftner, Thomas; Stubenrauch, Frank

2010-09-01

252

ModelE2-TOMAS development and evaluation using aerosol optical depths, mass and number concentrations  

NASA Astrophysics Data System (ADS)

The TwO-Moment Aerosol Sectional microphysics model (TOMAS) has been integrated into the state-of-the-art general circulation model, GISS ModelE2. TOMAS has the flexibility to select a size resolution as well as the lower size cutoff. A computationally efficient version of TOMAS is used here, which has 15 size bins covering 3 nm to 10 ?m aerosol dry diameter. For each bin, it simulates the total aerosol number concentration and mass concentrations of sulphate, pure elementary carbon (hydrophobic), mixed elemental carbon (hydrophilic), hydrophobic organic matter, hydrophilic organic matter, sea salt, mineral dust, ammonium, and aerosol-associated water. This paper provides a detailed description of the ModelE2-TOMAS model and evaluates the model against various observations including aerosol precursor gas concentrations, aerosol mass and number concentrations, and aerosol optical depths. Additionally, global budgets in ModelE2-TOMAS are compared with those of other global aerosol models, and the TOMAS model is compared to the default aerosol model in ModelE2, which is a bulk aerosol model. Overall, the ModelE2-TOMAS predictions are within the range of other global aerosol model predictions, and the model has a reasonable agreement with observations of sulphur species and other aerosol components as well as aerosol optical depth. However, ModelE2-TOMAS (as well as the bulk aerosol model) cannot capture the observed vertical distribution of sulphur dioxide over the Pacific Ocean possibly due to overly strong convective transport. The TOMAS model successfully captures observed aerosol number concentrations and cloud condensation nuclei concentrations. Anthropogenic aerosol burdens in the bulk aerosol model running in the same host model as TOMAS (ModelE2) differ by a few percent to a factor of 2 regionally, mainly due to differences in aerosol processes including deposition, cloud processing, and emission parameterizations. Larger differences are found for naturally emitted aerosols such as sea salt and mineral dust. With TOMAS, ModelE2 has three different aerosol models (the bulk aerosol model and modal-based aerosol microphysics model, MATRIX) and allows exploration of the uncertainties associated with aerosol modelling within the same host model, NASA GISS ModelE2.

Lee, Y. H.; Adams, P. J.; Shindell, D. T.

2014-09-01

253

E2F-1 overexpression inhibits human gastric cancer MGC-803 cell growth in vivo  

PubMed Central

AIM: To evaluate the influence of E2F-1 on the growth of human gastric cancer (GC) cells in vivo and the mechanism involved. METHODS: E2F-1 recombinant lentiviral vectors were injected into xenograft tumors of MGC-803 cells in nude mice, and then tumor growth was investigated. Overexpression of transcription factor E2F-1 was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting analysis. Apoptosis rates were determined using a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. Expression levels of certain cell cycle regulators and apoptosis-related proteins, such as Bax, survivin, Bcl-2, cyclin D1, S-phase kinase-associated protein 2, and c-Myc were examined by Western blotting and RT-PCR. RESULTS: Xenograft tumors of MGC-803 cells in nude mice injected with E2F-1 recombinant lentiviral vectors stably overexpressed the E2F-1 gene as measured by semi-quantitative RT-PCR (relative mRNA expression: 0.10 ± 0.02 vs 0.05 ± 0.02 for control vector and 0.06 ± 0.03 for no infection; both P < 0.01) and Western blotting (relative protein expression: 1.90 ± 0.05 vs 1.10 ± 0.03 in control vector infected and 1.11 ± 0.02 for no infection; both P < 0.01). The growth-curve of tumor volumes revealed that infection with E2F-1 recombinant lentiviral vectors significantly inhibited the growth of human GC xenografts (2.81 ± 1.02 vs 6.18 ± 1.15 in control vector infected and 5.87 ± 1.23 with no infection; both P < 0.05) at 15 d after treatment. TUNEL analysis demonstrated that E2F-1 overexpression promoted tumor cell apoptosis (18.6% ± 2.3% vs 6.7% ± 1.2% in control vector infected 6.3% ± 1.2% for no infection; both P < 0.05). Furthermore, lentiviral vector-mediated E2F-1 overexpression increased the expression of Bax and suppressed survivin, Bcl-2, cyclin D1, Skp2, and c-Myc expression in tumor tissue. CONCLUSION: E2F-1 inhibits growth of GC cells via regulating multiple signaling pathways, and may play an important role in targeted therapy for GC. PMID:25593464

Wei, Wei-Yuan; Yan, Lin-Hai; Wang, Xiao-Tong; Li, Lei; Cao, Wen-Long; Zhang, Xiao-Shi; Zhan, Ze-Xu; Yu, Han; Xie, Yu-Bo; Xiao, Qiang

2015-01-01

254

The cellular bromodomain protein Brd4 has multiple functions in E2-mediated papillomavirus transcription activation.  

PubMed

The cellular bromodomain protein Brd4 functions in multiple processes of the papillomavirus life cycle, including viral replication, genome maintenance, and gene transcription through its interaction with the viral protein, E2. However, the mechanisms by which E2 and Brd4 activate viral transcription are still not completely understood. In this study, we show that recruitment of positive transcription elongation factor b (P-TEFb), a functional interaction partner of Brd4 in transcription activation, is important for E2's transcription activation activity. Furthermore, chromatin immunoprecipitation (ChIP) analyses demonstrate that P-TEFb is recruited to the actual papillomavirus episomes. We also show that E2's interaction with cellular chromatin through Brd4 correlates with its papillomavirus transcription activation function since JQ1(+), a bromodomain inhibitor that efficiently dissociates E2-Brd4 complexes from chromatin, potently reduces papillomavirus transcription. Our study identifies a specific function of Brd4 in papillomavirus gene transcription and highlights the potential use of bromodomain inhibitors as a method to disrupt the human papillomavirus (HPV) life cycle. PMID:25140737

Helfer, Christine M; Yan, Junpeng; You, Jianxin

2014-08-01

255

Identification of E2F1 as a positive transcriptional regulator for {delta}-catenin  

SciTech Connect

{delta}-Catenin is upregulated in human carcinomas. However, little is known about the potential transcriptional factors that regulate {delta}-catenin expression in cancer. Using a human {delta}-catenin reporter system, we have screened several nuclear signaling modulators to test whether they can affect {delta}-catenin transcription. Among {beta}-catenin/LEF-1, Notch1, and E2F1, E2F1 dramatically increased {delta}-catenin-luciferase activities while {beta}-catenin/LEF-1 induced only a marginal increase. Rb suppressed the upregulation of {delta}-catenin-luciferase activities induced by E2F1 but did not interact with {delta}-catenin. RT-PCR and Western blot analyses in 4 different prostate cancer cell lines revealed that regulation of {delta}-catenin expression is controlled mainly at the transcriptional level. Interestingly, the effects of E2F1 on {delta}-catenin expression were observed only in human cancer cells expressing abundant endogenous {delta}-catenin. These studies identify E2F1 as a positive transcriptional regulator for {delta}-catenin, but further suggest the presence of strong negative regulator(s) for {delta}-catenin in prostate cancer cells with minimal endogenous {delta}-catenin expression.

Kim, Kwonseop [Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, 600 Moye Street, Greenville, NC 27834 (United States); College of Pharmacy and Research Institute of Drug development, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Oh, Minsoo; Ki, Hyunkyoung [College of Pharmacy and Research Institute of Drug development, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Wang Tao; Bareiss, Sonja [Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, 600 Moye Street, Greenville, NC 27834 (United States); Fini, M. Elizabeth. [Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136 (United States); Li Dawei [Department of Pathology, Harvard Medical School, Boston, MA 20115 (United States); Lu Qun [Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, 600 Moye Street, Greenville, NC 27834 (United States)], E-mail: luq@ecu.edu

2008-05-02

256

Quantitative autoradiographic localization of prostaglandin E2 binding sites in monkey diencephalon.  

PubMed

Quantitative autoradiography was performed to investigate the mapping of prostaglandin E2 binding sites in the Macaca fuscata fuscata diencephalon. Autoradiographs were prepared by incubation of 10-micron-thick serial frozen sections with 3H-prostaglandin E2 and were processed by using a rotating drum-scanner and a computer-assisted image-processing system with 3H-microscales as standards. The localization of prostaglandin E2 binding sites was remarkably discrete in the diencephalon. The highest concentrations were found in the median and medial preoptic areas, supramammilary nucleus of the hypothalamus, and centromedian nucleus of the thalamus. High density was observed in the medial and dorsal hypothalamic areas; paraventricular, anterior, dorsomedial, and infundibular nuclei of the hypothalamus; and in the anteroventral, periventricular, paraventricular, laterodorsal, and habenular nuclei of the thalamus. The distribution correlates well with the known effects of prostaglandin E2 and may also give us useful clues in unveiling the novel role of prostaglandin E2 in a variety of brain functions. PMID:3164357

Watanabe, Y; Watanabe, Y; Hayaishi, O

1988-06-01

257

E2-RING expansion of the NEDD8 cascade confers specificity to cullin modification  

SciTech Connect

Ubiquitin and ubiquitin-like proteins (UBLs) are directed to targets by cascades of E1, E2, and E3 enzymes. The largest ubiquitin E3 subclass consists of cullin-RING ligases (CRLs), which contain one each of several cullins (CUL1, -2, -3, -4, or -5) and RING proteins (RBX1 or -2). CRLs are activated by ligation of the UBL NEDD8 to a conserved cullin lysine. How is cullin NEDD8ylation specificity established? Here we report that, like UBE2M (also known as UBC12), the previously uncharacterized E2 UBE2F is a NEDD8-conjugating enzyme in vitro and in vivo. Biochemical and structural analyses indicate how plasticity of hydrophobic E1-E2 interactions and E1 conformational flexibility allow one E1 to charge multiple E2s. The E2s have distinct functions, with UBE2M/RBX1 and UBE2F/RBX2 displaying different target cullin specificities. Together, these studies reveal the molecular basis for and functional importance of hierarchical expansion of the NEDD8 conjugation system in establishing selective CRL activation.

Huang, D.T.; Ayrault, O.; Hunt, H.W.; Taherbhoy, A.M.; Duda, D.M.; Scott, D.C.; Borg, L.A.; Neale, G.; Murray, P.J.; Roussel, M.F.; Schulman, B.A.; (SJCH)

2009-03-27

258

The E2F3—Oncomir 1 axis is activated in Wilms Tumor  

PubMed Central

Oncomir-1 is an oncogenic cluster of microRNAs located on chromosome 13. Previous in vitro studies demonstrated that it is transcriptionally regulated by the transcription factor E2F3. In this report we combine expression profiling of both messenger RNA (mRNA) and micro RNAs (miRNA) in Wilms tumor (WT) samples to provide the first evidence that the E2F3—Oncomir 1 axis, previously identified in cell culture, is deregulated in primary human tumors. Analysis of RNA expression signatures demonstrated that an E2F3 gene signature was activated in all Wilms tumor samples analyzed, in contrast to other kidney tumors. This finding was validated by immunohistochemistry (IHC) on the protein level. Expression of E2F3 was lowest in early stage tumors, and highest in metastatic tissue. Expression profiling of miRNAs in WT showed that expression of each measured member of the Oncomir-1 family was highest in WT relative to other kidney tumor subtypes. Quantitative polymerase chain reaction (PCR) confirmed that these microRNAs were overexpressed in Wilms tumor relative to normal kidney tissue. These results suggest that the E2F3—Oncomir-1 axis is activated in Wilms tumor. Our study also demonstrates the utility of integrated genomics combining gene signature analysis with miRNA expression profiling to identify protein-miRNA interactions that are perturbed in disease states. PMID:18519660

Kort, Eric J.; Farber, Leslie; Tretiakova, Maria; Petillo, David; Furge, Kyle A.; Yang, Ximing J.; Cornelius, Albert; Teh, Bin T.

2008-01-01

259

Enhanced osteoblast proliferation and collagen gene expression by estradiol  

SciTech Connect

Estrogens play a crucial role in the development of postmenopausal osteoporosis. However, the mechanism by which estrogens exert their effects on bone is unknown. To examine possible direct effects of 17{beta}-estradiol on bone-forming cells, the authors used pure rat osteoblast-like cells in vitro as a model. Osteoblast-like cells prepared from calvaria of newborn rats were cultured serum-free in methylcellulose-containing medium for 21 days. Osteoblast-like cells proliferate selectively into clonally derived cell clusters of spherical morphorlogy. 17{beta}-Estradiol at concentrations of 0.1 nM and 1 nM enhanced osteoblast-like cell proliferation by 41% and 68% above vehicle-treated controls. The biologically inactive stereoisomer 17{alpha}-estradiol (same concentrations) had no effect. Moreover, the antiestrogen tamoxifen abolished the stimulation of osteoblast-like cell proliferation by 17{beta}-estradiol. After 21 days of culture, RNA was prepared and analyzed in a dot-hybridization assay for the abundance of pro{alpha}1(I) collagen mRNA. Steady-state mRNA levels were increased in cultures treated with 17{beta}-estradiol in a dose-dependent manner with maximal stimulation at 1 nM and 10 nM. At the same concentrations, the percentage of synthesized protein (labeled by ({sup 3}H)proline pulse) that was digestible by collagenase was increased, indicating that 17{beta}-estradiol acts as pretranslational levels to enhance synthesis of bone collagen. These data show that the osteoblast is a direct target for 17{beta}-estradiol.

Ernest, M.; Schmid, Ch.; Froesch, E.R. (University Hospital of Zurich (Switzerland))

1988-04-01

260

Degradation of estrogenic hormones in a silt loam soil.  

PubMed

Estrogenic hormones are endocrine-disrupting compounds, which disrupt the endocrine system function of animals and humans by mimicking and/or antagonizing endogenous hormones. With the application of sludge biosolid and animal manure as alternative fertilizers in agricultural lands, estrogens enter the soil and become an environmental concern. The degradation kinetics of 17beta-estradiol, an estrogenic hormone of major concern, in a silt loam soil were investigated in this study. It was found that 17beta-estradiol degraded rapidly in nonsterilized soil with a half-life of 0.17 day. The degradation rate constant was proportional to the percentage of nonsterilized soil, indicating that microorganisms are directly responsible for the rapid degradation of 17beta-estradiol in soil. The half-life of 17beta-estradiol in 20% nonsterilized soil was slightly shortened from 1.3 to 0.69 day with the increase of soil moisture from 10 to 20% and was greatly decreased from 4.9 to 0.92 day with the increase of temperature from 15 to 25 degrees C. The coexistence of 40 micromol kg (-1) sulfadimethoxine, a veterinary antibiotic, decreased the degradation rate constant of 17beta-estradiol from 0.750 +/- 0.038 to 0.492 +/- 0.016 day (-1). The degradation kinetics of another three estrogenic hormones, including 17alpha-estradiol, estrone, and estriol, were also investigated and compared. Estrone was identified as a degradation product of 17beta-estradiol and the most persistent hormone among the four investigated estrogens. Estriol was observed in the degradation of estrone and 17alpha-estradiol. PMID:18778070

Xuan, Richeng; Blassengale, Alma A; Wang, Qiquan

2008-10-01

261

B(E2) Predictions for Even-Even Nuclei in the Differential Equation Model  

E-print Network

We use the recently developed Differential Equation Model for the reduced electric quadrupole transition probability B(E2) for predicting its values for a wide range of even-even nuclides almost throughout the nuclear landscape from Neon to Californium. This is made possible as the principal equation in the model, namely, the differential equation connecting the B(E2) value of a given nucleus with its derivatives with respect to neutron and proton numbers provides two different recursion relations, each connecting three different neighboring even-even nuclei from lower to higher mass numbers and vice-verse. These relations helped us to extrapolate from known to unknown terrain of the B(E2) landscape and thereby facilitate its predictions throughout.

R. C. Nayak; S. Pattnaik

2014-05-13

262

(e, 2e) triple differential cross sections of Ca atoms at low energies  

NASA Astrophysics Data System (ADS)

Recently, several theoretical studies (Hitawala et al 2008 J. Phys. B: At. Mol. Opt. Phys. 41 035205; Khajuria and Deshmukh 2008 Phys. Rev. A 78 024702; Chauhan et al 2005 Phys. Rev. A 71 032708) have been reported to analyze the measurements of triple differential cross section (TDCS) for (e, 2e) processes on Ca (4s2) atom in coplanar geometry (Murray 2005 Phys. Rev. A 72 062711). In this paper, the (e, 2e) TDCS of the Ca atom has been revisited with the inclusion of correlation-polarization potential and post-collision interaction in the distorted wave Born approximation formalism. We note that the present attempt significantly improves the understanding of (e, 2e) processes at low energies on Ca atom. Still there are several discrepancies between the experimental and theoretical results that require more theoretical attempts to explain them properly.

Purohit, G.; Patidar, Vinod; Sud, K. K.

2009-12-01

263

Developmental silencing and independency from E2F of apoptotic gene expression in postmitotic tissues.  

PubMed

The involvement of caspases in postmitotic cell death is controversial. Here we report that adult brain and heart are devoid of many key pro-apoptotic proteins due to a progressive postnatal silencing event involving a reduction of their transcript levels. E2F has been shown to control cell cycle progression and to be transcriptional activator of apoptotic genes. However, our data demonstrate that apoptotic gene expression in heart, brain and liver, as well as cardiac and neuronal apoptotic gene silencing during development, are E2F-independent events. Therefore, the genes regulating caspase-dependent cell death are expressed in embryonic organs in an E2F-independent manner and a developmental-related silencing event represses these genes in postmitotic adult tissues. PMID:18037375

Zhang, Jisheng; Bahi, Núria; Zubiaga, Ana M; Comella, Joan X; Llovera, Marta; Sanchis, Daniel

2007-12-22

264

The Amyloid Precursor Protein (APP) Does Not Have a Ferroxidase Site in Its E2 Domain  

PubMed Central

The ubiquitous 24-meric iron-storage protein ferritin and multicopper oxidases such as ceruloplasmin or hephaestin catalyze oxidation of Fe(II) to Fe(III), using molecular oxygen as oxidant. The ferroxidase activity of these proteins is essential for cellular iron homeostasis. It has been reported that the amyloid precursor protein (APP) also has ferroxidase activity. The activity is assigned to a ferroxidase site in the E2 domain of APP. A synthetic 22-residue peptide that carries the putative ferroxidase site of E2 domain (FD1 peptide) has been claimed to encompass the same activity. We previously tested the ferroxidase activity of the synthetic FD1 peptide but we did not observe any activity above the background oxidation of Fe(II) by molecular oxygen. Here we used isothermal titration calorimetry to study Zn(II) and Fe(II) binding to the natural E2 domain of APP, and we employed the transferrin assay and oxygen consumption measurements to test the ferroxidase activity of the E2 domain. We found that this domain neither in the presence nor in the absence of the E1 domain binds Fe(II) and it is not able to catalyze the oxidation of Fe(II). Binding of Cu(II) to the E2 domain did not induce ferroxidase activity contrary to the presence of redox active Cu(II) centers in ceruloplasmin or hephaestin. Thus, we conclude that E2 or E1 domains of APP do not have ferroxidase activity and that the potential involvement of APP as a ferroxidase in the pathology of Alzheimer’s disease must be re-evaluated. PMID:23977245

Honarmand Ebrahimi, Kourosh; Dienemann, Christian; Hoefgen, Sandra; Than, Manuel E.; Hagedoorn, Peter-Leon; Hagen, Wilfred R.

2013-01-01

265

Novel explanation of charmoniumlike structure in e+e-??(2S)?+?-  

NASA Astrophysics Data System (ADS)

We first present a nonresonant description to charmoniumlike structure Y(4360) in the ?(2S)?+?- invariant mass spectrum of the e+e-??(2S)?+?- process. The Y(4360) structure is depicted well by the interference effect of the production amplitudes of e+e-??(2S)?+?- via the intermediate charmonia ?(4160)/?(4415) and direct e+e- annihilation into ?(2S)?+?-. This fact shows that Y(4360) is not a genuine resonance, which naturally explains why Y(4360) was only reported in its hidden-charm decay channel ?(2S)?+?- and was not observed in the exclusive open-charm decay channel or R-value scan.

Chen, Dian-Yong; He, Jun; Liu, Xiang

2011-04-01

266

Energy-momentum density of graphite by (e,2e) spectroscopy  

SciTech Connect

The energy-resolved electron momentum density of graphite has been measured along a series of well-defined directions using (e,2e) spectroscopy. This is the first measurement of this kind, to our knowledge, performed on a single-crystal target with a thoroughly controlled orientation which clearly demonstrates the different nature of the {sigma} and {pi} bands in graphite. Good agreement between the calculated density and the measured one is found, further establishing the fact that (e,2e) spectroscopy yields more direct and complete information on the valence electronic structure than any other method. {copyright} {ital 1997} {ital The American Physical Society}

Vos, M.; Fang, Z.; Canney, S.; Kheifets, A.; McCarthy, I.E. [Electronic Structure of Materials Centre, Flinders University of South Australia, GPO Box 2100, Adelaide 5001 (Australia)] [Electronic Structure of Materials Centre, Flinders University of South Australia, GPO Box 2100, Adelaide 5001 (Australia); Weigold, E. [Institute of Advanced Studies, the Australian National University, Canberra 0200 (Australia)] [Institute of Advanced Studies, the Australian National University, Canberra 0200 (Australia)

1997-07-01

267

Positioning reduction in the real-time phase of Chang'E-2 satellite  

NASA Astrophysics Data System (ADS)

The precision of VLBI tracking delays and the positioning reduction results during the real-time tracking phase of the Chang'E-2 satellite are statistically analyzed. The application of the positioning reduction to the real-time monitoring of pivotal arcs of the Chang'E-2 satellite is discussed. The technical specifications of the tests of tracking and control systems in X-band are estimated and evaluated via the positioning reduction method. Useful methodology and software are prepared and practical experience in engineering and technology is accumulated for the follow-up lunar and deep space explorations of China.

Li, JinLing; Liu, Li; Zheng, WeiMin; Sun, ZhongMiao

2012-02-01

268

Second-order Born effect in coplanar doubly symmetric (e,2e) collisions for sodium  

NASA Astrophysics Data System (ADS)

The second-order distorted wave Born approximation (DWBA) method is employed to investigate the triple differential cross sections (TDCS) of coplanar doubly symmetric (e,2e) collisions for alkali target sodium at excess energies of 6-60 eV. Comparing with the first-order DWBA calculations, the inclusion of second-order Born term in the scattering amplitude improves the degree of agreement with experiments, especially for backward scattering region of TDCS. This indicates the present second-order Born term is capable to give a reasonable correction to DWBA model in studying coplanar symmetric (e,2e) problems in low and intermediate energy range.

Wang, Yang; Jiao, Liguang; Zhou, Yajun

2012-06-01

269

Pleiotropic effects of Prostaglandin E2 in hematopoiesis; Prostaglandin E2 and other eicosanoids regulate hematopoietic stem and progenitor cell function  

PubMed Central

Eicosanoids have been implicated in the physiological regulation of hematopoiesis with pleiotropic effects on hematopoietic stem cells and various classes of lineage restricted progenitor cells. Herein we review the effects of eicosanoids on hematopoiesis, focusing on new findings implicating prostaglandin E2 in enhancing hematopoietic stem cell engraftment by enhancing stem cell homing, survival and self-renewal. We also describe a role for cannabinoids in hematopoiesis. Lastly, we discuss the yin and yang of various eicosanoids in modulating hematopoietic stem and progenitor cell functions and summarize potential strategies to take advantage of these effects for therapeutic benefit for hematopoietic stem cell transplantation. PMID:21722751

Pelus, Louis M.; Hoggatt, Jonathan

2011-01-01

270

Early estrogen treatment of female zebra finches masculinizes the brain pathway for learned vocalizations.  

PubMed

Telencephalic nucleus HVC and its two efferent targets, RA and X, play essential roles in the production of complex, learned vocalizations in the male zebra finch. Normal females do not produce these learned vocalizations; HVC, RA, and X are small in volume, and HVC and RA are not synaptically connected. We have shown that estrogen treatment during development causes females to learn and produce male-like vocalizations. This article describes the neural masculinization of these E2 females, replicating and extending the work of others. Female zebra finches were treated with 17 beta-estradiol (E2) at hatching, at 14-22 days of age, or as adults. In adulthood, the volumes of nucleus RA and area X were measured and the efferent projections of nucleus HVC examined using the anterograde tracer PHA-L. Early, sustained E2 treatment caused the greatest increase in the volume of RA and X, the innervation of RA and X by HVC axons, and the masculinization of auditory responses of cells in RA. Treatments that lasted for a shorter period or started later in development resulted in different patterns of partial brain masculinization. E2 treatment in adulthood had no effect on the volume of RA or X or their innervation by HVC. Bilateral lesions of the tracheosyringeal nerves or of HVC had the same effects on the male-typical vocalizations produced by E2 females as they do on the vocalizations produced by males. These results demonstrate that the neural masculinization of telencephalic nuclei induced by E2 treatment sets up a functional circuit in females similar to one in males that enables the learning and production of complex vocalizations. PMID:1765783

Simpson, H B; Vicario, D S

1991-10-01

271

Estrogen and pure antiestrogen fulvestrant (ICI 182 780) augment cell-matrigel adhesion of MCF-7 breast cancer cells through a novel G protein coupled estrogen receptor (GPR30)-to-calpain signaling axis.  

PubMed

Fulvestrant (ICI 182 780, ICI) has been used in treating patients with hormone-sensitive breast cancer, yet initial or acquired resistance to endocrine therapies frequently arises and, in particular, cancer recurs as metastasis. We demonstrate here that both 17-beta-estradiol (E2) and ICI enhance cell adhesion to matrigel in MCF-7 breast cancer cells, with increased autolysis of calpain 1 (large subunit) and proteolysis of focal adhesion kinase (FAK), indicating calpain activation. Additionally, either E2 or ICI induced down-regulation of estrogen receptor ? without affecting G protein coupled estrogen receptor 30 (GPR30) expression. Interestingly, GPR30 agonist G1 triggered calpain 1 autolysis but not calpain 2, whereas ER agonist diethylstilbestrol caused no apparent calpain autolysis. Furthermore, the actions of E2 and ICI on calpain and cell adhesion were tremendously suppressed by G15, or knockdown of GPR30. E2 and ICI also induced phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2), and suppression of ERK1/2 phosphorylation by U0126 profoundly impeded calpain activation triggered by estrogenic and antiestrogenic stimulations indicating implication of ERK1/2 in the GPR30-mediated action. Lastly, the E2- or ICI-induced cell adhesion was dramatically impaired by calpain-specific inhibitors, ALLN or calpeptin, suggesting requirement of calpain in the GPR30-associated action. These data show that enhanced cell adhesion by E2 and ICI occurs via a novel GPR30-ERK1/2-calpain pathway. Our results indicate that targeting the GPR30 signaling may be a potential strategy to reduce metastasis and improve the efficacy of antiestrogens in treatment of advanced breast cancer. PMID:24440569

Chen, Yan; Li, Zheng; He, Yan; Shang, Dandan; Pan, Jigang; Wang, Hongmei; Chen, Huamei; Zhu, Zhuxia; Wan, Lei; Wang, Xudong

2014-03-01

272

Tumor suppressor TAp73 gene specifically responds to deregulated E2F activity in human normal fibroblasts.  

PubMed

Discrimination of oncogenic growth signals from normal growth signals is crucial for tumor suppression. The transcription factor E2F, the main target of pRB, plays central role in cell proliferation by activating growth-promoting genes. E2F also plays an important role in tumor suppression by activating growth-suppressive genes such as pro-apoptotic genes. The regulatory mechanism of the latter genes is not known in detail, especially in response to normal and oncogenic growth signals. E2F is physiologically activated by growth stimulation through phosphorylation of pRB. In contrast, upon dysfunction of pRB, a major oncogenic change, E2F is activated out of control by pRB, generating deregulated E2F activity. We show here that the tumor suppressor TAp73 gene, which can induce apoptosis independently of p53, responds to deregulated E2F activity, but not to physiological E2F activity induced by growth stimulation in human normal fibroblasts. We identified E2F-responsive elements (ERE73s) in TAp73 promoter that can specifically sense deregulated E2F activity. Moreover, RB1-deficient cancer cell lines harbored deregulated E2F activity that activated ERE73s and the TAp73 gene, which were suppressed by re-introduction of pRB. These results underscore the important role of deregulated E2F in activation of the TAp73 gene, a component of major intrinsic tumor suppressor pathways. PMID:22702391

Ozono, Eiko; Komori, Hideyuki; Iwanaga, Ritsuko; Tanaka, Tatsuya; Sakae, Takahiro; Kitamura, Hodaka; Yamaoka, Shoji; Ohtani, Kiyoshi

2012-08-01

273

Viral-mediated noisy gene expression reveals biphasic E2f1 response to MYC  

PubMed Central

Gene expression mediated by viral vectors is subject to cell-to-cell variability, which limits the accuracy of gene delivery. When coupled with single-cell measurements, however, such variability provides an efficient means to quantify signaling dynamics in mammalian cells. Here, we illustrate the utility of this approach by mapping the E2f1 response to MYC, serum stimulation, or both. Our results revealed an underappreciated mode of gene regulation: E2f1 expression first increased then decreased as MYC input increased. This biphasic pattern was also reflected in other nodes of the network including the miR-17-92 micro RNA cluster and p19Arf. A mathematical model of the network successfully predicted modulation of the biphasic E2F response by serum and a CDK inhibitor. In addition to demonstrating how noise can be exploited to probe signaling dynamics, our results reveal how coordination of the MYC/RB/E2F pathway enables dynamic discrimination of aberrant and normal levels of growth stimulation. PMID:21292160

Wong, Jeffrey V.; Yao, Guang; Nevins, Joseph R.; You, Lingchong

2011-01-01

274

Hepatitis C Virus Envelope Glycoprotein E2 Glycans Modulate Entry, CD81 Binding, and Neutralization?  

PubMed Central

Hepatitis C virus (HCV) is a major human pathogen that causes serious liver disease, including cirrhosis and hepatocellular carcinoma. The primary target cells of HCV are hepatocytes, and entry is restricted by interactions of the envelope glycoproteins, E1 and E2, with cellular receptors. E1 and E2 form noncovalently linked heterodimers and are heavily glycosylated. Glycans contribute to protein folding and transport as well as protein function. In addition, glycans associated with viral envelopes mask important functional domains from the immune system and attenuate viral immunogenicity. Here, we explored the role of N- and O-linked glycans on E2, which is the receptor binding subunit of the HCV envelope. We identified a number of glycans that are critical for viral entry. Importantly, we showed that the removal of several glycans significantly increased the inhibition of entry by sera from HCV-positive individuals. Only some of the glycans that affected entry and neutralization were also important for CD81 binding. Our results show that HCV envelope-associated glycans play a crucial role in masking functionally important regions of E2 and suggest a new strategy for eliciting highly neutralizing antibodies against this virus. PMID:17507469

Falkowska, Emilia; Kajumo, Francis; Garcia, Edie; Reinus, John; Dragic, Tatjana

2007-01-01

275

Intramolecular diffraction in (e, 2e) reactions of CX4 (X=F, Cl, Br)  

NASA Astrophysics Data System (ADS)

The remarkable discrepancies between the experimental momentum distributions and the calculated distributions within the plane wave impulse approximation (PWIA) were observed in (e, 2e) reaction of CF4, CCl4, and CBr4. The discrepancies evidently depend on the impact energy of electrons. One possible explanation is the intramolecular diffraction.

Ning, Chuangang; Zhu, Jingsheng; Deng, Jingkang; Miao, Yurun

2014-04-01

276

HUMAN T CELL RESPONSES TO HPV 16 E2 GENERATED WITH MONOCYTE-DERIVED DENDRITIC CELLS  

E-print Network

Persistent infection with human papillomavirus (HPV) type 16 has been implicated in the etiology of cervical-associated dis- eases. © 2001 Wiley-Liss, Inc. Key words: human papillomavirus (HPV); E2 protein; dendritic cells neoplasia (CIN); cervical cancer; vaccines Persistent infection with oncogenic human papillomaviruses (HPV

Gaston, Kevin

277

EARLY ELEMENTARY SCIENCE PARTNERSHIP (E2SP) THREE-YEAR SUMMATIVE REPORT  

E-print Network

students' science comprehension and achievement. Program Description The Early Elementary Science to which the E2SP reached its goals, the Center for Elementary Mathematics and Science Education (CEMSE and Museum Educators (MEs) log data across the program's duration support questionnaire findings that teacher

Patterson, Bruce D.

278

Environment to Environment (E2E) Communication Systems for Collaborative Work  

E-print Network

, USA ABSTRACT E2E is an initiative to harness the power of the World Wide Web (WWW) along. Moreover, various forms of interactions can be supported through the capabilities provided by the Web with the development and popularity of the World Wide Web. Internet based communication approaches have begun to make

Reif, Rafael

279

The E2 Domains of APP and APLP1 Share a Conserved Mode of Dimerization  

SciTech Connect

Amyloid precursor protein (APP) is genetically linked to Alzheimer's disease. APP is a type I membrane protein, and its oligomeric structure is potentially important because this property may play a role in its function or affect the processing of the precursor by the secretases to generate amyloid {beta}-peptide. Several independent studies have shown that APP can form dimers in the cell, but how it dimerizes remains controversial. At least three regions of the precursor, including a centrally located and conserved domain called E2, have been proposed to contribute to dimerization. Here we report two new crystal structures of E2, one from APP and the other from APLP1, a mammalian APP homologue. Comparison with an earlier APP structure, which was determined in a different space group, shows that the E2 domains share a conserved and antiparallel mode of dimerization. Biophysical measurements in solution show that heparin binding induces E2 dimerization. The 2.1 {angstrom} resolution electron density map also reveals phosphate ions that are bound to the protein surface. Mutational analysis shows that protein residues interacting with the phosphate ions are also involved in heparin binding. The locations of two of these residues, Arg-369 and His-433, at the dimeric interface suggest a mechanism for heparin-induced protein dimerization.

S Lee; Y Xue; J Hulbert; Y Wang; X Liu; B Demeler; Y Ha

2011-12-31

280

J U N E 2 8 , 2 010 NATIONAL SPACE POLICY  

E-print Network

J U N E 2 8 , 2 010 NATIONAL SPACE POLICY of the UNITED STATES of AMERICA #12 . As the leading space-faring nation, the United States is committed to addressing these challenges responsibility . The United States, therefore, calls on all nat

Rathbun, Julie A.

281

Dietary lipids, prostaglandin E 2 levels, and tooth movement in alveolar bone of rats  

Microsoft Academic Search

Summary A previous study showed that certain dietary lipids can alter arachidonic acid concentrations in alveolar bone. Because arachidonic acid is a precursor of prostaglandin (PG) E2, which is known to play an important role in orthodontic tooth movement, the purpose of the present study was to determine the effect of dietary lipids on PGE2 levels and tooth movement. Two

Petros P. Kokkinos; Robert Shaye; Bassima S. Alam; Syed Q. Alam

1993-01-01

282

Isoscalar E0, E1, and E2 strength in Ca-40  

E-print Network

The giant resonance region from 10 particles at small angles including 0 degrees. Strength corresponding to 97 +/- 11%, 108 +/- 12%, and 62 + 10-20 % of the isoscalar E0, E2, and E1 sum rules, respectively, was identified with centroids of 19...

Youngblood, David H.; Lui, YW; Clark, HL.

2001-01-01

283

Antigen-induced non-specific suppressor factor in sheep efferent lymph is prostaglandin E2.  

PubMed Central

Efferent lymph from the popliteal node of sheep challenged with antigen was found to suppress the in vitro transformation of sheep peripheral blood lymphocytes to a variety of antigens. The suppressor factor appeared 6-20 hr after challenged of the node and was shown to be prostaglandin E2, probably complexed to albumin. PMID:7251050

Hopkins, J; McConnell, I; Raniwalla, J

1981-01-01

284

1 | J u n e 2 0 1 1 RReessoouurrcceess ffoorr EEnngglliisshh LLaanngguuaaggee LLeeaarrnneerrss  

E-print Network

Bell, William. Death Wind PS8553.E53 D42 Mac, Carrie. Charmed PS8625.A23 C43 Murdoch, Patricia second language" or esl Example of keyword search to find multimedia: video? and ("english language search to the Education Library. Video: Every teacher a #12;3 | J u n e 2 0 1 1 video? and ("english

Graham, Nick

285

The nuclear factor ?B inhibitor (E)-2-fluoro-4?-methoxystilbene inhibits firefly luciferase  

PubMed Central

Photinus pyralis (firefly) luciferase is widely used as a reporter system to monitor alterations in gene promoter and/or signalling pathway activities in vitro. The enzyme catalyses the formation of oxyluciferin from D-luciferin in an ATP-consuming reaction involving photon emission. The purpose of the present study was to characterize the luciferase-inhibiting potential of (E)-2-fluoro-4?-methoxystilbene, which is known as a potent inhibitor of the NF-?B (nuclear factor ?B) signalling pathway that is used to modulate the NF-?B signalling pathway in vitro. Results show that (E)-2-fluoro-4?-methoxystilbene effectively inhibits firefly luciferase activity in cell lysates and living cells in a non-competitive manner with respect to the luciferase substrates D-luciferin and ATP. By contrast, the compound has no effect on Renilla and Gaussia luciferases. The mechanism of firefly luciferase inhibition by (E)-2-fluoro-4?-methoxystilbene, as well as its potency is comparable to its structure analogue resveratrol. The in vitro use of trans-stilbenes such as (E)-2-fluoro-4?-methoxystilbene or resveratrol compromises firefly luciferase reporter assays as well as ATP/luciferase-based cell viability assays. PMID:22789175

Braeuning, Albert; Vetter, Silvia

2012-01-01

286

The nuclear factor ?B inhibitor (E)-2-fluoro-4'-methoxystilbene inhibits firefly luciferase.  

PubMed

Photinus pyralis (firefly) luciferase is widely used as a reporter system to monitor alterations in gene promoter and/or signalling pathway activities in vitro. The enzyme catalyses the formation of oxyluciferin from D-luciferin in an ATP-consuming reaction involving photon emission. The purpose of the present study was to characterize the luciferase-inhibiting potential of (E)-2-fluoro-4'-methoxystilbene, which is known as a potent inhibitor of the NF-?B (nuclear factor ?B) signalling pathway that is used to modulate the NF-?B signalling pathway in vitro. Results show that (E)-2-fluoro-4'-methoxystilbene effectively inhibits firefly luciferase activity in cell lysates and living cells in a non-competitive manner with respect to the luciferase substrates D-luciferin and ATP. By contrast, the compound has no effect on Renilla and Gaussia luciferases. The mechanism of firefly luciferase inhibition by (E)-2-fluoro-4'-methoxystilbene, as well as its potency is comparable to its structure analogue resveratrol. The in vitro use of trans-stilbenes such as (E)-2-fluoro-4'-methoxystilbene or resveratrol compromises firefly luciferase reporter assays as well as ATP/luciferase-based cell viability assays. PMID:22789175

Braeuning, Albert; Vetter, Silvia

2012-12-01

287

Dynamic Tensile Testing of Kevlar 49 Fabrics ; Barzin Mobasher, Ph.D., P.E.2  

E-print Network

Dynamic Tensile Testing of Kevlar 49 Fabrics Deju Zhu1 ; Barzin Mobasher, Ph.D., P.E.2 of strain. Kevlar-49 fabrics were tested in tension within a strain-rate range of 25 to 170 sÃ?1 using a high nature of Kevlar-49 fabric results in large displacements and shape changes during tests. Noncontacting

Mobasher, Barzin

288

F-box protein Skp2: a novel transcriptional target of E2F  

PubMed Central

The F-box-containing protein Skp2 plays a critical role in coordinating the G1/S transition and progression through the S phase of the mammalian cell cycle. Skp2 is overexpressed in a broad spectrum of human cancers and the expression level correlates with tumor malignancy. However, the Skp2 gene is neither amplified nor rearranged in most human cancers and the underlying mechanism of Skp2 overexpression remains poorly understood. We show here that the Skp2 gene contains a functional E2F response element (hSRE2). Ectopic expression of E2F1 induces expression of the endogenous Skp2 gene in human fibroblast cells, whereas antisense-mediated knockdown of E2F1 in human tumor cell lines reduces expression of endogenous Skp2 gene. The hSRE2 element not only participates in activation of Skp2 promoter function during normal cell cycle progression into S phase, it is also required for the high-level Skp2 gene expression in many human tumor cell lines. These results reveal Skp2 as a novel target for E2F regulation that is disrupted in several human tumor cell lines. PMID:16331253

Zhang, L; Wang, C

2006-01-01

289

Cell Reports A Genetic Screen Identifies TCF3/E2A  

E-print Network

target gene CDKN1A (p21), an in- hibitor of cell-cycle progression, versus BBC3 (PUMA), a key mediator of apoptosis. Our screen identified numerous factors whose depletion cre- ates an imbalance in the p21:PUMA re- pressing PUMA across cancer cell types of multiple origins. Accordingly, TCF3/E2A depletion

290

An Intronic microRNA Links Rb/E2F and EGFR Signaling  

PubMed Central

The importance of microRNAs in the regulation of various aspects of biology and disease is well recognized. However, what remains largely unappreciated is that a significant number of miRNAs are embedded within and are often co-expressed with protein-coding host genes. Such a configuration raises the possibility of a functional interaction between a miRNA and the gene it resides in. This is exemplified by the Drosophila melanogaster dE2f1 gene that harbors two miRNAs, mir-11 and mir-998, within its last intron. miR-11 was demonstrated to limit the proapoptotic function of dE2F1 by repressing cell death genes that are directly regulated by dE2F1, however the biological role of miR-998 was unknown. Here we show that one of the functions of miR-998 is to suppress dE2F1-dependent cell death specifically in rbf mutants by elevating EGFR signaling. Mechanistically, miR-998 operates by repressing dCbl, a negative regulator of EGFR signaling. Significantly, dCbl is a critical target of miR-998 since dCbl phenocopies the effects of miR-998 on dE2f1-dependent apoptosis in rbf mutants. Importantly, this regulation is conserved, as the miR-998 seed family member miR-29 repressed c-Cbl, and enhanced MAPK activity and wound healing in mammalian cells. Therefore, the two intronic miRNAs embedded in the dE2f1 gene limit the apoptotic function of dE2f1, but operate in different contexts and act through distinct mechanisms. These results also illustrate that examining an intronic miRNA in the context of its host's function can be valuable in elucidating the biological function of the miRNA, and provide new information about the regulation of the host gene itself. PMID:25058496

Truscott, Mary; Islam, Abul B. M. M. K.; Lightfoot, James; López-Bigas, Núria; Frolov, Maxim V.

2014-01-01

291

Single Cell Analysis to locate the Restriction Point with respect to E2F Expression  

NASA Astrophysics Data System (ADS)

The restriction point is a G1-phase checkpoint that regulates passage through the cell cycle and is misregulated in all known types of cancer. The Rb-E2F switch is thought to be one of the most relevant molecular mechanisms which regulate the restriction point in mammalian cells. However, recent experiments have brought the timing of the restriction point into question. In previous studies, cells were analyzed as populations and this prevented an accurate determination of the restriction point. By creating and analyzing an E2F-GFP reporter in single cells, we can pinpoint the timing of E2F activation and determine whether it coincides with the restriction point. Using calcium phosphate and Fugene,we transfected human embryonic kidney (293T) cells with a CMV-GFP plasmid and an E2F-GFP reporter. Based on our results, it appears that calcium phosphate is more effective than Fugene at transfecting mammalian cells. The calcium phosphate transfection had 9.59% more fluorescent cells than Fugene. However, this result only occurred with the CMV-GFP plasmid and not the E2F-GFP reporter, which was not properly expressed in human embryonic kidney (293T) cells. We will continue troubleshooting to fix this reporter as we proceed with our research. Once the reporter is properly cloned, we will transfect it into retinal pigmented epithelial (RPE1-hTERT) cells using the calcium phosphate method. RPE1-hTERT cells are an immortalized with telomerase and are more close to normal cells than tumor-derived cell lines. Through this research we will better comprehend commitment to the mammalian cell cycle.

Pimienta, R.; Johnson, A.

2011-12-01

292

VirE2: A Unique ssDNA-Compacting Molecular Machine  

PubMed Central

The translocation of single-stranded DNA (ssDNA) across membranes of two cells is a fundamental biological process occurring in both bacterial conjugation and Agrobacterium pathogenesis. Whereas bacterial conjugation spreads antibiotic resistance, Agrobacterium facilitates efficient interkingdom transfer of ssDNA from its cytoplasm to the host plant cell nucleus. These processes rely on the Type IV secretion system (T4SS), an active multiprotein channel spanning the bacterial inner and outer membranes. T4SSs export specific proteins, among them relaxases, which covalently bind to the 5' end of the translocated ssDNA and mediate ssDNA export. In Agrobacterium tumefaciens, another exported protein—VirE2—enhances ssDNA transfer efficiency 2000-fold. VirE2 binds cooperatively to the transferred ssDNA (T-DNA) and forms a compact helical structure, mediating T-DNA import into the host cell nucleus. We demonstrated—using single-molecule techniques—that by cooperatively binding to ssDNA, VirE2 proteins act as a powerful molecular machine. VirE2 actively pulls ssDNA and is capable of working against 50-pN loads without the need for external energy sources. Combining biochemical and cell biology data, we suggest that, in vivo, VirE2 binding to ssDNA allows an efficient import and pulling of ssDNA into the host. These findings provide a new insight into the ssDNA translocation mechanism from the recipient cell perspective. Efficient translocation only relies on the presence of ssDNA binding proteins in the recipient cell that compacts ssDNA upon binding. This facilitated transfer could hence be a more general ssDNA import mechanism also occurring in bacterial conjugation and DNA uptake processes. PMID:18303950

Jacob, Susan; Engel, Andreas; Hegner, Martin

2008-01-01

293

Selective roles of E2Fs for ErbB2- and Myc-mediated mammary tumorigenesis.  

PubMed

Previous studies have demonstrated that cyclin D1, an upstream regulator of the Rb/E2F pathway, is an essential component of the ErbB2/Ras (but not the Wnt/Myc) oncogenic pathway in the mammary epithelium. However, the role of specific E2fs for ErbB2/Ras-mediated mammary tumorigenesis remains unknown. Here, we show that in the majority of mouse and human primary mammary carcinomas with ErbB2/HER2 overexpression, E2f3a is up-regulated, raising the possibility that E2F3a is a critical effector of the ErbB2 oncogenic signaling pathway in the mammary gland. We examined the consequence of ablating individual E2fs in mice on ErbB2-triggered mammary tumorigenesis in comparison to a comparable Myc-driven mammary tumor model. We found that loss of E2f1 or E2f3 led to a significant delay in tumor onset in both oncogenic models, whereas loss of E2f2 accelerated mammary tumorigenesis driven by Myc-overexpression. Furthermore, southern blot analysis of final tumors derived from conditionally deleted E2f3(-/loxP) mammary glands revealed that there is a selection against E2f3(-/-) cells from developing mammary carcinomas, and that such selection pressure is higher in the presence of ErbB2 activation than in the presence of Myc activation. Taken together, our data suggest oncogenic activities of E2F1 and E2F3 in ErbB2- or Myc-triggered mammary tumorigenesis, and a tumor suppressor role of E2F2 in Myc-mediated mammary tumorigenesis. PMID:24276244

Wu, L; de Bruin, A; Wang, H; Simmons, T; Cleghorn, W; Goldenberg, L E; Sites, E; Sandy, A; Trimboli, A; Fernandez, S A; Eng, C; Shapiro, C; Leone, G

2015-01-01

294

Api5 Contributes to E2F1 Control of the G1/S Cell Cycle Phase Transition  

PubMed Central

Background The E2f transcription factor family has a pivotal role in controlling the cell fate in general, and in particular cancer development, by regulating the expression of several genes required for S phase entry and progression through the cell cycle. It has become clear that the transcriptional activation of at least one member of the family, E2F1, can also induce apoptosis. An appropriate balance of positive and negative regulators appears to be necessary to modulate E2F1 transcriptional activity, and thus cell fate. Methodology/Principal Findings In this report, we show that Api5, already known as a regulator of E2F1 induced-apoptosis, is required for the E2F1 transcriptional activation of G1/S transition genes, and consequently, for cell cycle progression and cell proliferation. Api5 appears to be a cell cycle regulated protein. Removal of Api5 reduces cyclin E, cyclin A, cyclin D1 and Cdk2 levels, causing G1 cell cycle arrest and cell cycle delay. Luciferase assays established that Api5 directly regulates the expression of several G1/S genes under E2F1 control. Using protein/protein and protein/DNA immunoprecipitation studies, we demonstrate that Api5, even if not physically interacting with E2F1, contributes positively to E2F1 transcriptional activity by increasing E2F1 binding to its target promoters, through an indirect mechanism. Conclusion/Significance The results described here support the pivotal role of cell cycle related proteins, that like E2F1, may act as tumor suppressors or as proto-oncogenes during cancer development, depending on the behavior of their positive and negative regulators. According to our findings, Api5 contributes to E2F1 transcriptional activation of cell cycle-associated genes by facilitating E2F1 recruitment onto its target promoters and thus E2F1 target gene transcription. PMID:23940755

Garcia-Jove Navarro, Marina; Basset, Céline; Arcondéguy, Tania; Touriol, Christian; Perez, Guillaume; Prats, Hervé; Lacazette, Eric

2013-01-01

295

ERbeta shifts from mitochondria to nucleus during estrogen-induced neoplastic transformation of human breast epithelial cells and is involved in estrogen-induced synthesis of mitochondrial respiratory chain proteins.  

PubMed

Both estrogen receptors (ER) alpha (ERalpha) and beta (ERbeta) are localized in the nucleus, plasma membrane, and mitochondria, where they mediate the different physiological effects of estrogens. It has been observed that the relative subcellular localization of ERs is altered in several cancer cells. We have demonstrated that MCF-10F cells, the immortal and non-tumorigenic human breast epithelial cells (HBEC) that are ERalpha-negative and ERbeta-positive, are transformed in vitro by 17beta-estradiol (E(2)), generating highly invasive cells that are tumorigenic in severe combined immunodeficient mice. E(2)-transformed MCF-10F (trMCF) cells exhibit progressive loss of ductulogenesis, invasive (bsMCF) and tumorigenic (caMCF) phenotypes. Immunolocalization of ERbeta by confocal fluorescent microscopy and electron microscopy revealed that ERbeta is predominantly localized in mitochondria of MCF-10F and trMCF cells. Silencing ERbeta expression with ERbeta-specific small interference RNA (siRNA-ERbeta) markedly diminishes both nuclear and mitochondrial ERbeta in MCF-10F cells. The ERbeta shifts from its predominant localization in the mitochondria of MCF-10F and trMCF cells to the nucleus of bsMCF cells, becoming predominantly nuclear in caMCF cells. Furthermore, we demonstrated that the mitochondrial ERbeta in MCF-10F cells is involved in E(2)-induced expression of mitochondrial DNA (mtDNA)-encoded respiratory chain (MRC) proteins. This is the first report of an association of changes in the subcellular localization of ERbeta with various stages of E(2)-induced transformation of HBEC and a functional role of mitochondrial ERbeta in mediating E(2)-induced MRC protein synthesis. Our findings provide a new insight into one of the potential roles of ERbeta in human breast cancer. PMID:17604135

Chen, Jin-Qiang; Russo, Patricia A; Cooke, Carol; Russo, Irma H; Russo, Jose

2007-12-01

296

Ovarian steroid hormone-regulated uterine remodeling occurs independently of macrophages in mice.  

PubMed

Macrophages are abundant in the uterine stroma and are intimately juxtaposed with other cell lineages comprising the uterine epithelial and stromal compartments. We postulated that macrophages may participate in mediating or amplifying the effects of ovarian steroid hormones to facilitate the uterine remodeling that is a characteristic feature of every estrus cycle and is essential for pregnancy. Using the Cd11b-Dtr transgenic mouse model with an ovariectomy and hormone replacement strategy, we depleted macrophages to determine their role in hormone-driven proliferation of uterine epithelial and stromal cells and uterine vascular development. Following diphtheria toxin (DT) administration, approximately 85% of EMR1-positive (EMR1(+)) macrophages, as well as 70% of CD11C(+) dendritic cells, were depleted from Cd11b-Dtr mice. There was no change in bromodeoxyuridine incorporation into epithelial cells induced to proliferate by administration of 17beta-estradiol (E2) to ovariectomized mice or into stromal cells induced to proliferate in response to E2 and progesterone (P4), and the resulting sizes and structures of the luminal epithelial and stromal cell compartments were not altered compared with those of leukocyte replete controls. Depletion of CD11B(+) myeloid cells failed to alter the density or pattern of distribution of uterine blood vessels, as identified by staining PECAM1-positive endothelial cells in the uterine stroma of E2- or E2 combined with P4 (E2P4)-treated ovariectomized mice. These experiments support the interpretation that macrophages are dispensable to regulation of proliferative events induced by steroid hormones in the cycling and early pregnant mouse uterus to establish the epithelial, stromal, and vascular architecture which is critical for normal reproductive competence. PMID:25061095

Care, Alison S; Ingman, Wendy V; Moldenhauer, Lachlan M; Jasper, Melinda J; Robertson, Sarah A

2014-09-01

297

An oestrogen membrane receptor participates in estradiol actions for the prevention of amyloid-beta peptide1-40-induced toxicity in septal-derived cholinergic SN56 cells.  

PubMed

Although oestrogen [17 beta-estradiol (E2)]-related neuroprotection has been demonstrated in different models, the involvement of non-classical oestrogen receptors (ERs) remains unexplored. Using the SN56 cholinergic cell line, we present evidence indicating that an ER associated with the plasma membrane participates in oestrogen-dependent inhibition of cell death induced by amyloid-beta peptide (A beta) toxicity. Similarly to E2 alone, a 15-min exposure to estradiol-horseradish peroxidase (E-HRP) significantly reduced A beta-induced cell death. This effect was decreased by the ER antagonist ICI 182,780 as well as by MC-20 antibody directed to a region neighbouring the ligand-binding domain of ER alpha. Using confocal microscopy on unpermeabilized SN56 cells exposed to MC-20 antibody, we identified a protein at the plasma membrane level. Western blot analysis of purified SN56 cell membrane fractions using MC-20 antibody revealed the presence of one band with the same electrophoretic mobility as intracellular ER alpha. Using conjugated forms of the steroid, E-HRP and E2 conjugated to bovine serum albumin-FITC, we demonstrated by confocal microscopy that SN56 cells contain surface binding sites for E2. Binding of both conjugates was blocked by pre-incubation with E2 and decreased by either ICI 182,780 or MC-20 antibody in a concentration-dependent manner. Thus, a membrane-related ER that shares some structural homologies with ER alpha may participate in oestrogen-mediated neuroprotection. PMID:12753077

Marin, Raquel; Guerra, Borja; Morales, Araceli; Díaz, Mario; Alonso, Rafael

2003-06-01

298

Structure Determination and Characterization of the Vitamin B[superscript 6] Degradative Enzyme (E)-2-(Acetamidomethylene)succinate Hydrolase  

SciTech Connect

The gene identification and kinetic characterization of (E)-2-(acetamidomethylene)succinate (E-2AMS) hydrolase has recently been described. This enzyme catalyzes the final reaction in the degradation of vitamin B{sub 6} and produces succinic semialdehyde, acetate, ammonia, and carbon dioxide from E-2AMS. The structure of E-2AMS hydrolase was determined to 2.3 {angstrom} using SAD phasing. E-2AMS hydrolase is a member of the {alpha}/{beta} hydrolase superfamily and utilizes a serine/histidine/aspartic acid catalytic triad. Mutation of either the nucleophilic serine or the aspartate resulted in inactive enzyme. Mutation of an additional serine residue in the active site causes the enzyme to be unstable and is likely structurally important. The structure also provides insight into the mechanism of hydrolysis of E-2AMS and identifies several potential catalytically important residues.

McCulloch, Kathryn M.; Mukherjee, Tathagata; Begley, Tadhg P.; Ealick, Steven E. (Cornell); (TAM)

2010-06-22

299

Jab1/CSN5 mediates E2F dependent expression of mitotic and apoptotic but not DNA replication targets.  

PubMed

The E2F transcription factors are critical regulators of cell cycle and cell fate control. Several classes of E2F target genes have been categorized based on their roles in DNA replication, mitosis, apoptosis, DNA repair, etc. How E2Fs coordinate the appropriate and timely expression of these functionally disparate gene products is poorly understood at a molecular level. We previously showed that the E2F1 binding partner Jab1/CSN5 promotes E2F1-dependent induction of apoptosis but not proliferation. To better understand how Jab1 regulates E2F1 dependent transcription, we performed gene expression analysis to identify E2F target genes most and least affected by shRNA depletion of Jab1. We find that a significant number of apoptotic and mitotic E2F target genes are poorly expressed in cells lacking Jab1/CSN5, whereas DNA replication genes are generally still highly expressed. Chromatin immunoprecipitation analysis indicates that both Jab1 and E2F1 co-occupy apoptotic and mitotic, but not DNA replication target genes. We explored a potential connection between PI3K activity and Jab1/E2F1 target gene induction, and found that E2F1/Jab1 co-induction of apoptotic target genes can be inhibited by activated PI3K. Furthermore, PI3K activity interferes with formation of the E2F1/Jab1 complex by co-immunoprecipitation. Jab1/CSN5 is upregulated in a variety of human tumors, but it's unclear how its pro-proliferatory and apoptotic functions are regulated in this context. We explored the link between increased Jab1 levels and PI3K function in tumors and detected a highly significant correlation between elevated Jab1/CSN5 levels and PI3K activity in breast, ovarian, lung and prostate cancers. PMID:21937878

Lu, Huarui; Liang, Xudong; Issaenko, Olga A; Hallstrom, Timothy C

2011-10-01

300

BMI1 is a target gene of E2F-1 and is strongly expressed in primary neuroblastomas  

Microsoft Academic Search

The oncogene BMI1 encodes a polycomb group transcription factor that is required for embryonic development and self-renewal of stem cells. Despite these important functions little is known about the regulation of BMI1 expression. A cDNA microarray based search for target genes of E2F-1 in neuro- blastoma cells expressing a 4-OHT-regulated E2F-1- ER fusion protein identified many hitherto unknown E2F-1 regulated

Katrin Nowak; Kornelius Kerl; Daniel Fehr; Christoph Kramps; Christine Gessner; Katrin Killmer; Birgit Samans; Bernd Berwanger; Holger Christiansen; Werner Lutz

2006-01-01

301

Intermediate-energy Coulomb excitation of 104Sn: Moderate E 2 strength decrease approaching 100Sn  

NASA Astrophysics Data System (ADS)

The reduced transition probability B (E 2 )? of the first excited 2+ state in the nucleus 104Sn was measured via Coulomb excitation in inverse kinematics at intermediate energies. A value of 0.173(28) e2b 2 was extracted from the absolute cross section on a Pb target. Feeding contributions in 104Sn from higher lying states were estimated by a reference measurement of the stable 112Sn. Corresponding only to a moderate decrease of excitation strength relative to the almost constant values observed in the proton-rich, even-A Sn-114106 isotopes, present state-of-the-art shell-model predictions, which include proton and neutron excitations across the N =Z =50 shell closures as well as standard polarization charges, underestimate the experimental findings.

Doornenbal, P.; Takeuchi, S.; Aoi, N.; Matsushita, M.; Obertelli, A.; Steppenbeck, D.; Wang, H.; Audirac, L.; Baba, H.; Bednarczyk, P.; Boissinot, S.; Ciemala, M.; Corsi, A.; Furumoto, T.; Isobe, T.; Jungclaus, A.; Lapoux, V.; Lee, J.; Matsui, K.; Motobayashi, T.; Nishimura, D.; Ota, S.; Pollacco, E. C.; Sakurai, H.; Santamaria, C.; Shiga, Y.; Sohler, D.; Taniuchi, R.

2014-12-01

302

E2 enzyme inhibition by stabilization of a low affinity interface with ubiquitin  

PubMed Central

Weak protein interactions between ubiquitin and the ubiquitin-proteasome system (UPS) enzymes that mediate its covalent attachment to substrates serve to position ubiquitin for optimal catalytic transfer. We show that a small molecule inhibitor of the E2 ubiquitin conjugating enzyme Cdc34A, called CC0651, acts by trapping a weak interaction between ubiquitin and the E2 donor ubiquitin binding site. A structure of the ternary CC0651-Cdc34A-ubiquitin complex reveals that the inhibitor engages a composite binding pocket formed from Cdc34A and ubiquitin. CC0651 also suppresses the spontaneous hydrolysis rate of the Cdc34A-ubiquitin thioester, without overtly affecting the interaction between Cdc34A and the RING domain subunit of the E3 enzyme. Stabilization of the numerous other weak interactions between ubiquitin and UPS enzymes by small molecules may be a feasible strategy to selectively inhibit different UPS activities. PMID:24316736

St-Cyr, Daniel J.; Ziemba, Amy; Garg, Pankaj; Plamondon, Serge; Auer, Manfred; Sidhu, Sachdev; Marinier, Anne; Kleiger, Gary; Tyers, Mike; Sicheri, Frank

2014-01-01

303

Modeling method and preliminary model of Asteroid Toutatis from Chang'E-2 optical images  

NASA Astrophysics Data System (ADS)

Shape modeling is fundamental to the analysis of dynamic environment and motion around asteroid. Chang'E-2 successfully made a flyby of Asteroid 4179 Toutatis and obtained plenty of high-resolution images during the mission. In this paper, the modeling method and preliminary model of Asteroid Toutatis are discussed. First, the optical images obtained by Chang'E-2 are analyzed. Terrain and silhouette features in images are described. Then, the modeling method based on previous radar model and preliminary information from optical images is proposed. A preliminary polyhedron model of Asteroid Toutatis is established. Finally, the spherical harmonic coefficients of Asteroid Toutatis based on the polyhedron model are obtained. Some parameters of model are analyzed and compared. Although the model proposed in this paper is only a preliminary model, this work offers a valuable reference for future high-resolution models.

Li, Xiang-Yu; Qiao, Dong

2014-06-01

304

Second-order Born calculation of coplanar symmetric (e, 2e) process on Mg  

NASA Astrophysics Data System (ADS)

The second-order distorted wave Born approximation (DWBA) method is employed to investigate the triple differential cross sections (TDCS) of coplanar doubly symmetric (e, 2e) collisions for magnesium at excess energies of 6 eV-20 eV. Comparing with the standard first-order DWBA calculations, the inclusion of the second-order Born term in the scattering amplitude improves the degree of agreement with experiments, especially for backward scattering region of TDCS. This indicates that the present second-order Born term is capable to give a reasonable correction to DWBA model in studying coplanar symmetric (e, 2e) problems of two-valence-electron target in low energy range.

Zhang, Yong-Zhi; Wang, Yang; Zhou, Ya-Jun

2014-06-01

305

M1-E2 interference in the Zeeman spectra of Bi I  

SciTech Connect

Studies of the M1-E2 interference effect in the mixed-type forbidden lines 461.5, 647.6, and 875.5 nm of Bi I are reported. A special computer program considering the interference effect was designed to obtain the predicted contours of the Zeeman structures of the lines. By variation of free parameters describing the line shapes and the electric-quadrupole admixtures, the calculated profiles were fitted to the recorded spectra. The E2 admixtures found are (7.84{+-}0.14)%, (17.5{+-}0.4)%, and (0.70{+-}0.11)% for the 461.5, 647.6, and 875.5 nm lines, respectively. Our results are compared with recent theories and other experiments.

Werbowy, S.; Kwela, J. [Institute of Experimental Physics, University of Gdansk, Wita Stwosza 57, 80-952 Gdansk (Poland)

2008-02-15

306

The chromatin remodeller CHD8 is required for E2F-dependent transcription activation of S-phase genes  

PubMed Central

The precise regulation of S-phase–specific genes is critical for cell proliferation. How the repressive chromatin configuration mediated by the retinoblastoma protein and repressor E2F factors changes at the G1/S transition to allow transcription activation is unclear. Here we show ChIP-on-chip studies that reveal that the chromatin remodeller CHD8 binds ?2000 transcriptionally active promoters. The spectrum of CHD8 target genes was enriched in E2F-dependent genes. We found that CHD8 binds E2F-dependent promoters at the G1/S transition but not in quiescent cells. Consistently, CHD8 was required for G1/S-specific expression of these genes and for cell cycle re-entry on serum stimulation of quiescent cells. We also show that CHD8 interacts with E2F1 and, importantly, loading of E2F1 and E2F3, but not E2F4, onto S-specific promoters, requires CHD8. However, CHD8 recruiting is independent of these factors. Recruiting of MLL histone methyltransferase complexes to S-specific promoters was also severely impaired in the absence of CHD8. Furthermore, depletion of CHD8 abolished E2F1 overexpression-dependent S-phase stimulation of serum-starved cells, highlighting the essential role of CHD8 in E2F-dependent transcription activation. PMID:24265227

Subtil-Rodríguez, Alicia; Vázquez-Chávez, Elena; Ceballos-Chávez, María; Rodríguez-Paredes, Manuel; Martín-Subero, José I.; Esteller, Manel; Reyes, José C.

2014-01-01

307

A robust cell cycle control mechanism limits E2F-induced proliferation of terminally differentiated cells in vivo  

PubMed Central

Terminally differentiated cells in Drosophila melanogaster wings and eyes are largely resistant to proliferation upon deregulation of either E2F or cyclin E (CycE), but exogenous expression of both factors together can bypass cell cycle exit. In this study, we show this is the result of cooperation of cell cycle control mechanisms that limit E2F-CycE positive feedback and prevent cycling after terminal differentiation. Aberrant CycE activity after differentiation leads to the degradation of E2F activator complexes, which increases the proportion of CycE-resistant E2F repressor complexes, resulting in stable E2F target gene repression. If E2F-dependent repression is lost after differentiation, high anaphase-promoting complex/cyclosome (APC/C) activity degrades key E2F targets to limit cell cycle reentry. Providing both CycE and E2F activities bypasses exit by simultaneously inhibiting the APC/C and inducing a group of E2F target genes essential for cell cycle reentry after differentiation. These mechanisms are essential for proper development, as evading them leads to tissue outgrowths composed of dividing but terminally differentiated cells. PMID:20548101

Katzaroff, Alexia J.

2010-01-01

308

Sequence Variation in the E2-Binding Domain of HPV16 and Biological Function Evaluation in Tunisian Cervical Cancers  

PubMed Central

HPV16 E2 variants have different effects on the transcriptional activity of the LCR. In this study, we examined the nucleotide and amino acid sequence variation within the HPV16 E2 gene and to correlate with disease progression. E2 gene disruption was detected by PCR amplification of the entire E2 gene using a single set of primers. Nucleotide variations were analyzed by bidirectional sequencing. mRNA expression patterns of E6 and E7 gene transcripts were evaluated by a reverse transcriptase-PCR method (RT-PCR). The detection of intact E2 genes was significantly higher among controls than cases (81.8% versus 37.5%, resp., P < 0.05). Among the E subgroup, variation at position 3684 C>A results in the amino acid substitution T310K and was more common among the E2 undisrupted cases (7/9; 77.7%), compared to controls (2/9; 22.2%). In addition, specific sequence variations identified in the E2 ORF at positions 3684 C>A were associated with increased viral oncogenes E6-E7 production. Besides HPV16 E2 disruption, the 3684 C>A variation within undisrupted E2 genes could be involved in an alternative mechanism for deregulating the expression of the HPV16 E6 and E7 oncogenes and appears to be a major factor contributing to the development of cervical cancer in Tunisian women. PMID:25032221

Kahla, Saloua; Kochbati, Lotfi; Hammami, Samia; Chanoufi, Mohamed Badis; Maalej, Mongi; Oueslati, Ridha

2014-01-01

309

A comparison of misoprostol and prostaglandin E 2 gel for preinduction cervical ripening and labor induction  

Microsoft Academic Search

Objective: Our purpose was to compare the safety ad efficacy of intravaginal misoprostal versus intracervical prostaglandin E2 (dinoprostone) gel for preinduction cervical ripening and induction of labor.Study design: One hundred thirty-five patients with indications for induction of labor and unfavorable cercices were randomly assigned to receive either intravaginal misoprostol or intracervical dinoprostate. Fifty microgram tablets of misoprostol were placed in

Deborah A. Wing; Margaret M. Jones; Ann Rahall; T. Murphy Goodwin; Richard H. Paul

1995-01-01

310

E2GKpro: An evidential evolving multi-modeling approach for system behavior prediction with applications  

NASA Astrophysics Data System (ADS)

Nonlinear dynamical systems identification and behavior prediction are difficult problems encountered in many areas of industrial applications, such as fault diagnosis and prognosis. In practice, the analytical description of a nonlinear system directly from observed data is a very challenging task because of the too large number of the related parameters to be estimated. As a solution, multi-modeling approaches have lately been applied and consist in dividing the operating range of the system under study into different operating regions easier to describe by simpler functions to be combined. In order to take into consideration the uncertainty related to the available data as well as the uncertainty resulting from the nonlinearity of the system, evidence theory is of particular interest, because it permits the explicit modeling of doubt and ignorance. In the context of multi-modeling, information of doubt may be exploited to properly segment the data and take into account the uncertainty in the transitions between the operating regions. Recently, the Evidential Evolving Gustafson-Kessel algorithm (E2GK) has been proposed to ensure an online partitioning of the data into clusters that correspond to operating regions. Based on E2GK, a multi-modeling approach called E2GKpro is introduced in this paper, which dynamically performs the estimation of the local models by upgrading and modifying their parameters while data arrive. The proposed algorithm is tested on several datasets and compared to existing approaches. The results show that the use of virtual centroids in E2GKpro account for its robustness to noise and generating less operating regions while ensuring precise predictions.

Serir, Lisa; Ramasso, Emmanuel; Nectoux, Patrick; Zerhouni, Noureddine

2013-05-01

311

Cardiovascular effects of prostaglandin F2a and prostaglandin E2  

Microsoft Academic Search

Little is known of the cardiovascular functions of prostaglandins in non-mammalian vertebrates. There are indications that prostaglandins may have a function in haemostasis by constricting blood vessels in filament arteries in the fish gill after injury. Our aim was to ex- amine the cardiovascular effect of the prostaglandins F2a (PGF2a )a nd E 2 (PGE2) with emphasis on branchial circulation.

L. Sundin

312

Cardiovascular effects of prostaglandin F 2 a and prostaglandin E 2 in Atlantic cod ( Gadus morhua )  

Microsoft Academic Search

Little is known of the cardiovascular functions of prostaglandins in non-mammalian vertebrates. There are indications that prostaglandins may have a function in haemostasis by constricting blood vessels in filament arteries in the fish gill after injury. Our aim was to examine the cardiovascular effect of the prostaglandins F2! (PGF2!) and E2 (PGE2) with emphasis on branchial circulation. Intra-arterial injections of

K.-O. Stensløkken; L. Sundin; G. Nilsson

2002-01-01

313

Novel role for prostaglandin E2 in fish hepatocytes: regulation of glucose metabolism  

Microsoft Academic Search

Prostaglandin E2 (PGE2) potently activated glycogenolysis and gluconeogenesis in isolated rockfish (Sebastes caurinus) hepatocytes. The average degree of activation for glyco- genolysis was 6·40·67-fold (meanS.E.M.; n=37), and could be as much as 19-fold. Analysis of dose- concentration relationships between glycogenolytic actions and PGE2 concentrations yielded an EC50 around 120 nM in hepatocyte suspensions and 2 nM for hepatocytes immobilized on

E R Busby; G A Cooper; T P Mommsen

2002-01-01

314

Serum Antibodies to Porphyromonas gingivalis Block the Prostaglandin E 2 Response to Lipopolysaccharide by Mononuclear Cells  

Microsoft Academic Search

The ability of rabbit and monkey immune sera to neutralize prostaglandin E2 (PGE2) production by human monocytes stimulated with lipopolysaccharide (LPS) was examined. CD14-dependent LPS activation of PGE2 was examined under assay conditions which allowed the comparison of preimmune and immune sera. Serum obtained from rabbits immunized with formalin-fixed Porphyromonas gingivalis cells dramatically reduced the amount of PGE2 produced in

BRIAN W. BAINBRIDGE; ROY C. PAGE; RICHARD P. DARVEAU

1997-01-01

315

Advanced Stirling Convertor (ASC-E2) Performance Testing at NASA Glenn Research Center  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG Project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). For this purpose, four pairs of ASCs capable of operating to 850 C and designated with the model number ASC-E2, were delivered by Sunpower of Athens, OH, to GRC in 2010. The ASC-E2s underwent a series of tests that included workmanship vibration testing, performance mapping, and extended operation. Workmanship vibration testing was performed following fabrication of each convertor to verify proper hardware build. Performance mapping consisted of operating each convertor at various conditions representing the range expected during a mission. Included were conditions representing beginning-of-mission (BOM), end-of-mission (EOM), and fueling. This same series of tests was performed by Sunpower prior to ASC-E2 delivery. The data generated during the GRC test were compared to performance before delivery. Extended operation consisted of a 500-hour period of operation with conditions maintained at the BOM point. This was performed to demonstrate steady convertor performance following performance mapping. Following this initial 500-hour period, the ASC-E2s will continue extended operation, controller development and special durability testing, during which the goal is to accumulate tens of thousands of hours of operation. Data collected during extended operation will support reliability analysis. Performance data from these tests is summarized in this paper.

Oriti, Salvatore; Wilson, Scott

2011-01-01

316

Advanced Stirling Convertor (ASC-E2) Performance Testing at NASA Glenn Research Center  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG Project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). For this purpose, four pairs of ASCs capable of operating to 850 C and designated with the model number ASC-E2, were delivered by Sunpower of Athens, Ohio, to GRC in 2010. The ASC-E2s underwent a series of tests that included workmanship vibration testing, performance mapping, and extended operation. Workmanship vibration testing was performed following fabrication of each convertor to verify proper hardware build. Performance mapping consisted of operating each convertor at various conditions representing the range expected during a mission. Included were conditions representing beginning-of-mission (BOM), end-of-mission (EOM), and fueling. This same series of tests was performed by Sunpower prior to ASC-E2 delivery. The data generated during the GRC test were compared to performance before delivery. Extended operation consisted of a 500-hr period of operation with conditions maintained at the BOM point. This was performed to demonstrate steady convertor performance following performance mapping. Following this initial 500-hr period, the ASC-E2s will continue extended operation, controller development and special durability testing, during which the goal is to accumulate tens of thousands of hours of operation. Data collected during extended operation will support reliability analysis. Performance data from these tests is summarized in this paper.

Oriti, Salvatore; Wilson, Scott

2011-01-01

317

Effects of Prostaglandin E2 on Alveolar Bone Resorption during Orthodontic Tooth Movement  

Microsoft Academic Search

Twenty Sprague-Dawley rats weighing 280–300 g were divided into two groups often animals each.They were treated by daily submucosal injections of 50 ?g prostaglandin E2 (PGE2) per kilogram body weight into the region below the apex of the left first maxillary molar (experimental) or vehicle into the region below the apex of the right first molar (control), for a period

Chung-Fu Chao; Chung Shih; Teen-Meei Wang; Tai-Hua Lo

1988-01-01

318

Low energy (e,2e) measurements of Xe in the symmetric non-coplanar geometry  

NASA Astrophysics Data System (ADS)

Low energy (e,2e) measurements from the valence state of xenon will be presented. Symmetric non-coplanar kinematics were utilized. Incident energies range from 5 to 40eV above the ionization potential with outgoing electron angles from 30-140°. Geometries from coplanar to perpendicular were investigated for each energy regime. These measurements show significant difference to those from helium and other noble gases, particularly at high incident electron angles.

Nixon, K. L.; Murray, A. J.

2012-11-01

319

A Proposal for Integrated Efficacy-to-Effectiveness (E2E) Clinical Trials  

PubMed Central

We propose an “efficacy-to-effectiveness” (E2E) clinical trial design, in which an effectiveness trial would commence seamlessly upon completion of the efficacy trial. Efficacy trials use inclusion/exclusion criteria to produce relatively homogeneous samples of participants with the target condition, conducted in settings that foster adherence to rigorous clinical protocols. Effectiveness trials use inclusion/exclusion criteria that generate heterogeneous samples that are more similar to the general patient spectrum, conducted in more varied settings, with protocols that approximate typical clinical care. In E2E trials, results from the efficacy trial component would be used to design the effectiveness trial component, to confirm and/or discern associations between clinical characteristics and treatment effects in typical care, and potentially to test new hypotheses. An E2E approach may improve the evidentiary basis for selecting treatments, expand understanding of the effectiveness of treatments in subgroups with particular clinical features, and foster incorporation of effectiveness information into regulatory processes. PMID:24060819

Selker, H P; Oye, K A; Eichler, H-G; Stockbridge, N L; Mehta, C R; Kaitin, K I; McElwee, N E; Honig, P K; Erban, J K; D'Agostino, R B

2014-01-01

320

Studies on orientation and rotation parameters of 4179 Toutatis from Chang'e-2 mission  

NASA Astrophysics Data System (ADS)

The ginger-shaped near-Earth asteroid 4179 Toutatis is close to a 4:1 orbital resonance with the Earth and has made close Earth flybys approximately every four years in the recent 20 years. China’s lunar probe Chang’e-2 achieved a successful flyby the Toutatis on 13th Dec 2012 during its most recent flyby of Earth. During the mission, a series of image with high resolution has been obtained. Combined with the radar model of Toutatis, these figures show the attitude of the asteroid from the camera’s point of view and the orientation of it is then deduced based on the attitude of the camera and the relative position between 4179 Toutatis and Chang'e-2 in our works. According to the previous ground-based observations and works on the rotation parameters of Toutatis, this paper studies the rotating rate of the asteroid in accordance with the imaging result of Toutatis by Chang’e-2 and puts forward a correction to the spin rate parameters.

Zhao, Yuhui; Ji, Jianghui; Hu, Shoucun

321

Signaling functions of ubiquitin in the 17?-estradiol (E2):estrogen receptor (ER) ? network.  

PubMed

Protein posttranslational modifications (PTMs) are signaling alterations that allow coordinating the cellular responses with the changes in the extracellular environment. In this way, the posttranslationally-modified protein becomes a switch node in the transduction network activated by the specific extracellular stimuli. It is now clear that this is the case also for protein ubiquitination: this extremely versatile PTM controls cell physiology through the modulation of protein stability as well as through the modulation of the dynamics of the intracellular signaling cascades. Recent evidence clearly indicates that such a complex scheme appears to be valid also for the 17?-estradiol (E2):estrogen receptor (ER) ? signal transduction pathways. Indeed, beside the long standing notion that ER? ubiquitination is required for the regulation of receptor stability, several laboratories, including our own, have clearly indicated that ER? ubiquitination also serves non-degradative functions. This review will reconsider the role of ubiquitination in E2:ER? signaling by particularly highlighting how the functions of the non-degradative ubiquitination impact on ER? activities and contribute to the modulation of E2-dependent physiological processes. PMID:21824518

La Rosa, Piergiorgio; Acconcia, Filippo

2011-11-01

322

CMIP5 historical simulations (1850-2012) with GISS ModelE2  

NASA Astrophysics Data System (ADS)

of climate change during the CMIP5 extended historical period (1850-2012) are compared to trends simulated by six versions of the NASA Goddard Institute for Space Studies ModelE2 Earth System Model. The six models are constructed from three versions of the ModelE2 atmospheric general circulation model, distinguished by their treatment of atmospheric composition and the aerosol indirect effect, combined with two ocean general circulation models, HYCOM and Russell. Forcings that perturb the model climate during the historical period are described. Five-member ensemble averages from each of the six versions of ModelE2 simulate trends of surface air temperature, atmospheric temperature, sea ice and ocean heat content that are in general agreement with observed trends, although simulated warming is slightly excessive within the past decade. Only simulations that include increasing concentrations of long-lived greenhouse gases match the warming observed during the twentieth century. Differences in twentieth-century warming among the six model versions can be attributed to differences in climate sensitivity, aerosol and ozone forcing, and heat uptake by the deep ocean. Coupled models with HYCOM export less heat to the deep ocean, associated with reduced surface warming in regions of deepwater formation, but greater warming elsewhere at high latitudes along with reduced sea ice. All ensembles show twentieth-century annular trends toward reduced surface pressure at southern high latitudes and a poleward shift of the midlatitude westerlies, consistent with observations.

Miller, Ron L.; Schmidt, Gavin A.; Nazarenko, Larissa S.; Tausnev, Nick; Bauer, Susanne E.; DelGenio, Anthony D.; Kelley, Max; Lo, Ken K.; Ruedy, Reto; Shindell, Drew T.; Aleinov, Igor; Bauer, Mike; Bleck, Rainer; Canuto, Vittorio; Chen, Yonghua; Cheng, Ye; Clune, Thomas L.; Faluvegi, Greg; Hansen, James E.; Healy, Richard J.; Kiang, Nancy Y.; Koch, Dorothy; Lacis, Andy A.; LeGrande, Allegra N.; Lerner, Jean; Menon, Surabi; Oinas, Valdar; Pérez García-Pando, Carlos; Perlwitz, Jan P.; Puma, Michael J.; Rind, David; Romanou, Anastasia; Russell, Gary L.; Sato, Makiko; Sun, Shan; Tsigaridis, Kostas; Unger, Nadine; Voulgarakis, Apostolos; Yao, Mao-Sung; Zhang, Jinlun

2014-06-01

323

CMIP5 Historical Simulations (1850-2012) with GISS ModelE2  

NASA Technical Reports Server (NTRS)

Observations of climate change during the CMIP5 extended historical period (1850-2012) are compared to trends simulated by six versions of the NASA Goddard Institute for Space Studies ModelE2 Earth System Model. The six models are constructed from three versions of the ModelE2 atmospheric general circulation model, distinguished by their treatment of atmospheric composition and the aerosol indirect effect, combined with two ocean general circulation models, HYCOM and Russell. Forcings that perturb the model climate during the historical period are described. Five-member ensemble averages from each of the six versions of ModelE2 simulate trends of surface air temperature, atmospheric temperature, sea ice and ocean heat content that are in general agreement with observed trends, although simulated warming is slightly excessive within the past decade. Only simulations that include increasing concentrations of long-lived greenhouse gases match the warming observed during the twentieth century. Differences in twentieth-century warming among the six model versions can be attributed to differences in climate sensitivity, aerosol and ozone forcing, and heat uptake by the deep ocean. Coupled models with HYCOM export less heat to the deep ocean, associated with reduced surface warming in regions of deepwater formation, but greater warming elsewhere at high latitudes along with reduced sea ice. All ensembles show twentieth-century annular trends toward reduced surface pressure at southern high latitudes and a poleward shift of the midlatitude westerlies, consistent with observations.

Miller, Ronald Lindsay; Schmidt, Gavin A.; Nazarenko, Larissa S.; Tausnev, Nick; Bauer, Susanne E.; DelGenio, Anthony D.; Kelley, Max; Lo, Ken K.; Ruedy, Reto; Shindell, Drew T.; Aleinov, Igor; Bauer, Mike; Bleck, Rainer; Canuto, Vittorio; Chen, Yonghua; Cheng, Ye; Clune, Thomas L.; Faluvegi, Greg; Healy, Richard J.; Kiang, Nancy Y.; Lacis, Andy A.; LeGrande, Allegra N.; Lerner, Jean; Rind, David; Russell, Gary L.

2014-01-01

324

Structural Flexibility of a Conserved Broadly Neutralizing Epitope in Hepatitis C Virus Glycoprotein E2.  

PubMed

Neutralizing antibodies (nAbs) targeting glycoprotein E2 are important to control hepatitis C virus (HCV) infection. One conserved antigenic site (amino acids 412-423) is disordered in the reported E2 structure, but a synthetic peptide mimicking this site forms a ?-hairpin in complex with three independent nAbs. Our structure of the same peptide in complex with nAb 3/11 demonstrates a strikingly different extended conformation. We also show that residues 412-423 are essential for virus entry, but not for E2 folding. Together with the neutralizing capacity of the 3/11 Fab this indicates an unexpected structural flexibility within this epitope. NAbs 3/11 and AP33 (recognizing the extended and ?-hairpin conformation, respectively) display similar neutralizing activity despite converse binding kinetics. Our results suggest that HCV utilizes conformational flexibility as immune evasion strategy contributing to the limited immunogenicity of this epitope in patients, similar to the conformational flexibility described for other enveloped and non-enveloped viruses. PMID:25473061

Meola, Annalisa; Tarr, Alexander W; England, Patrick; Meredith, Luke W; McClure, C Patrick; Foung, Steven K H; McKeating, Jane A; Ball, Jonathan K; Rey, Felix A; Krey, Thomas

2014-12-01

325

Dynamics of H{{e}^{2+}}+H ionization with exponential cosine-screened Coulomb potential  

NASA Astrophysics Data System (ADS)

Dynamics of H{{e}^{2+}}+H ionization in dense quantum plasmas (DQPs) has been studied by the classical trajectory Monte Carlo method. The interactions between charged particles have been described by the exponential cosine-screened Coulomb potential. It is found that ionization cross sections in plasma environments are obviously larger than those in plasma-free environments due to the screening effects. Cross sections for {{H}^{+}} also have been calculated for comparison. For {{H}^{+}}, cross sections increase with the increase of screening effects. However, for H{{e}^{2+}}, cross sections begin to decrease in strong screening effects at intermediate energies. Furthermore, H{{e}^{2+}} impact ionization cross sections in weakly coupled plasmas (WCPs) also have been calculated. The interactions have been described by the static screened Coulomb potential. It is found that when screening effects are weak, cross sections in DQPs and WCPs are approximately the same. As screening effects increase, cross sections in DQPs become larger than those in WCPs at high energies. However, when screening effects are strong enough, cross sections in DQPs become smaller than those in WCPs at low and intermediate energies.

Zhang, Ling-yu; Qi, Xin; Zhao, Xiao-ying; Zhang, Xun-chao; Xiao, Guo-qing; Duan, Wen-shan; Yang, Lei

2014-08-01

326

Estradiol rapidly inhibits soluble guanylyl cyclase expression in rat uterus  

NASA Technical Reports Server (NTRS)

Previous reports that investigated the regulation of the NO/soluble guanylyl cyclase (sGC)/cGMP pathway by estrogenic compounds have focused primarily on the levels of NO, NO-producing enzymes, and cGMP in various tissues. In this study, we demonstrate that 17beta-estradiol (E2) regulates the alpha(1) and beta(1) subunits of the NO receptor, sGC, at the mRNA and protein levels in rat uterus. Using real-time quantitative PCR, we found that within 1 h of in vivo E2 administration to rats, sGC mRNA levels begin to diminish. After 3 h, there is a maximal diminution of sGC mRNA expression (sGC alpha(1) 10% and sGC beta(1) 33% of untreated). This effect was blocked by the estrogen receptor antagonist, ICI 182,780, indicating that estrogen receptor is required. The effect of E2 also was observed in vitro with incubations of uterine tissue, indicating that the response does not depend on the secondary release of other hormones or factors from other tissues. Puromycin did not block the effect, suggesting the effects occur because of preexisting factors in uterine tissues and do not require new protein synthesis. Using immunoblot analysis, we found that sGC protein levels also were reduced by E2 over a similar time course as the sGC mRNA. We conclude that sGC plays a vital role in the NO/sGC/cGMP regulatory pathway during conditions of elevated estrogen levels in the rat uterus as a result of the reduction of sGC expression.

Krumenacker, J. S.; Hyder, S. M.; Murad, F.

2001-01-01

327

Downregulation of thymidylate synthase and E2F1 by arsenic trioxide in mesothelioma.  

PubMed

Malignant pleural mesothelioma is a global health issue. Arsenic trioxide (ATO) has been shown to suppress thymidylate synthase (TYMS) in lung adenocarcinoma and colorectal cancer, and induce apoptosis in acute promyelocytic leukemia. With TYMS as a putative therapeutic target, the effect of ATO in mesothelioma was therefore studied. A panel of 5 mesothelioma cell lines was used to study the effect of ATO on cell viability, protein expression, mRNA expression and TYMS activity by MTT assay, western blot, qPCR and tritium-release assay, respectively. The knockdown of TYMS and E2F1 was performed with a specific siRNA. Phosphatidylserine externalization and mitochondrial membrane depolarization were measured by Annexin V and JC-1 staining respectively. The in vivo effect of ATO was studied using a nude mouse xenograft model. Application of ATO demonstrated anticancer effects in the cell line model with clinically achievable concentrations. Downregulation of TYMS protein (except H226 cells and 1.25 µM ATO in H2052 cells) and mRNA expression (H28 cells), pRB1 (H28 cells) and E2F1 and TYMS activity (except H226 cells) were also evident. E2F1 knockdown decreased cell viability more significantly than TYMS knockdown. In general, thymidine kinase 1, ribonucleotide reductase M1, c-myc and skp2 were downregulated by ATO. p-c-Jun was downregulated in H28 cells while upregulated in 211H cells. Phosphatidylserine externalization, mitochondrial membrane depolarization, downregulation of Bcl-2 and Bcl-xL, and upregulation of Bak and cleaved caspase-3 were observed. In the H226 xenograft model, the relative tumor growth was aborted, and E2F1 was downregulated while cleaved caspase-3 was elevated and localized to the nucleus in the ATO treatment group. ATO has potent antiproliferative and cytotoxic effects in mesothelioma in vitro and in vivo, partially mediated through E2F1 targeting (less effect through TYMS targeting). There is sound scientific evidence to support the clinical application of ATO in treatment of mesothelioma. PMID:25335113

Lam, Sze-Kwan; Li, Yuan-Yuan; Zheng, Chun-Yan; Ho, James Chung-Man

2015-01-01

328

Imperial College London EEE 1L6 Autumn 2009 E2.2 Analogue Electronics Multiple stage amplifiers  

E-print Network

Imperial College London ­ EEE 1L6 Autumn 2009 E2.2 Analogue Electronics Multiple stage amplifiers Aims: · Examine a few common 2-transistor amplifiers: -- Differential amplifiers -- Cascode amplifiers amplifiers #12;Imperial College London ­ EEE 2L6 Autumn 2009 E2.2 Analogue Electronics Two stage BJT

Papavassiliou, Christos

329

THE E2/FRB PATHWAY REGULATION OF DNA REPLICATION AND PROTEIN BIOSYNTHESIS  

EPA Science Inventory

The E2F/Rb pathway plays a pivotal role in the control of cell cycle progression and regulates the expression of genes required for Gl/S transition. Our study examines the genomic response in Drosophila embryos after overexpression and mutation of E2F/Rb pathway molecules. Hierar...

330

The Human Papillomavirus (HPV) 16 E2 Protein Induces Apoptosis in the Absence of Other HPV Proteins and via a  

E-print Network

The Human Papillomavirus (HPV) 16 E2 Protein Induces Apoptosis in the Absence of Other HPV Proteins, Manchester M20 9BX, United Kingdom The human papillomavirus (HPV) E2 protein regu- lates viral gene. Papillomaviruses infect epithelial cells and generally induce the formation of benign hyperproliferative lesions

Gaston, Kevin

331

11 CFR 101.2 - Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)).  

Code of Federal Regulations, 2013 CFR

...agent of authorized committee (2 U.S.C. 432(e)(2)). 101.2 Section...CANDIDATE STATUS AND DESIGNATIONS (2 U.S.C. 432(e)) § 101.2 Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)). (a) Any...

2013-01-01

332

11 CFR 101.2 - Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)).  

Code of Federal Regulations, 2011 CFR

...agent of authorized committee (2 U.S.C. 432(e)(2)). 101.2 Section...CANDIDATE STATUS AND DESIGNATIONS (2 U.S.C. 432(e)) § 101.2 Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)). (a) Any...

2011-01-01

333

11 CFR 101.2 - Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)).  

...agent of authorized committee (2 U.S.C. 432(e)(2)). 101.2 Section...CANDIDATE STATUS AND DESIGNATIONS (2 U.S.C. 432(e)) § 101.2 Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)). (a) Any...

2014-01-01

334

11 CFR 101.2 - Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)).  

Code of Federal Regulations, 2012 CFR

...agent of authorized committee (2 U.S.C. 432(e)(2)). 101.2 Section...CANDIDATE STATUS AND DESIGNATIONS (2 U.S.C. 432(e)) § 101.2 Candidate as agent of authorized committee (2 U.S.C. 432(e)(2)). (a) Any...

2012-01-01

335

75 FR 79264 - E-2 Nonimmigrant Status for Aliens in the Commonwealth of the Northern Mariana Islands With Long...  

Federal Register 2010, 2011, 2012, 2013

This final rule amends Department of Homeland Security (DHS) regulations governing E-2 nonimmigrant treaty investors to establish procedures for classifying long-term investors in the Commonwealth of the Northern Mariana Islands (CNMI) as E-2 nonimmigrants. This final rule implements the CNMI nonimmigrant investor visa provisions of the Consolidated Natural Resources Act of 2008 extending the......

2010-12-20

336

Mutations in Drosophila DP and E2F distinguish G1–S progression from an associated transcriptional?program  

PubMed Central

The E2F transcription factor, a heterodimer of E2F and DP subunits, is capable of driving the G1–S transition of the cell cycle. However, mice in which the E2F-1 gene had been disrupted developed tumors, suggesting a negative role for E2F in controlling cell proliferation in some tissues. The consequences of disrupting the DP genes have not been reported. We screened for mutations that disrupt G1–S transcription late in Drosophila embryogenesis and identified five mutations in the dDP gene. Although mutations in dDP or dE2F nearly eliminate E2F-dependent G1–S transcription, S-phase still occurs. Cyclin E has been shown to be essential for S-phase in late embryogenesis, but in dDP and dE2F mutants the peaks of G1–S transcription of cyclin E are missing. Thus, greatly reduced levels of cyclin E transcript suffice for DNA replication until late in development. Both dDP and dE2F are necessary for viability, and mutations in the genes cause lethality at the late larval/pupal stage. The mutant phenotypes reveal that both genes promote progression of the cell cycle. PMID:9271122

Royzman, Irena; Whittaker, Allyson J.; Orr-Weaver, Terry L.

1997-01-01

337

Role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology  

E-print Network

Role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology Saori of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology. We studied the effect is primarily involved in CXCR4-mediated neurotoxicity and HIV neuropathogenesis. © 2006 Elsevier Inc. All

Meucci, Olimpia

338

The opposing roles of E2A and Id3 that orchestrate and enforce the naïve T cell fate  

PubMed Central

It is established that E2A and its antagonist, Id3, modulate developmental progression at the pre-TCR receptor (pre-TCR) and TCR checkpoints. Here we demonstrate that Id3 expression is elevated beyond the pre-TCR checkpoint, remains high in naive T cells and shows a bimodal pattern in the effector/memory population. We show how E2A promotes T-lineage specification and how pre-TCR mediated signaling affects E2A genome-wide occupancy. Thymi in Id3-deficient mice exhibited aberrant development of effector/memory cells, increased CXCR5 and Bcl6 expression, T-B cell conjugates and remarkably B cell follicles. Collectively, these data show how E2A acts globally to orchestrate T-lineage development and that Id3 antagonizes E2A activity beyond the pre-TCR checkpoint to enforce the naïve T cell fate. PMID:21857655

Miyazaki, Masaki; Rivera, Richard R; Miyazaki, Kazuko; Lin, Yin C; Agata, Yasutoshi; Murre, Cornelis

2011-01-01

339

High-precision B (E2) measurements of semi-magic Ni58,60,62,64 by Coulomb excitation  

NASA Astrophysics Data System (ADS)

High-precision reduced electric-quadrupole transition probabilities B (E2;01+?21+) have been measured from single-step Coulomb excitation of semi-magic Ni58,60,62,64 (Z=28) beams at 1.8 MeV per nucleon on a natural carbon target. The energy loss of the nickel beams through the carbon target were directly measured with a zero-degree Bragg detector and the absolute B (E2) values were normalized by Rutherford scattering. The B (E2) values disagree with recent lifetime studies that employed the Doppler-shift attenuation method. The present high-precision B (E2) values reveal an asymmetry about Ni62, midshell between N =28 and 40, with larger values towards Ni56 (Z =N=28). The experimental B (E2) values are compared with shell-model calculations in the full pf model space and the results indicate a soft Ni56 core.

Allmond, J. M.; Brown, B. A.; Stuchbery, A. E.; Galindo-Uribarri, A.; Padilla-Rodal, E.; Radford, D. C.; Batchelder, J. C.; Howard, M. E.; Liang, J. F.; Manning, B.; Varner, R. L.; Yu, C.-H.

2014-09-01

340

Remodeling of the Human Papillomavirus Type 11 Replication Origin into Discrete Nucleoprotein Particles and Looped Structures by the E2 Protein  

PubMed Central

The human papillomavirus (HPV) origin (ori) of DNA replication shares a common theme with many DNA control elements in having multiple binding sites for one or more proteins spaced over several hundred base pairs. The HPV type-11 ori spans 103 bp and contains three palindromic binding sites (E2BS-2, E2BS-3, and E2BS-4) for the dimeric E2 origin binding protein. These sites are separated by 64 bp and 3 bp. E2BS-1 is located 288 bp upstream of E2BS-2 and is not required for efficient transient or cell-free replication. In this study, electron microscopy was used to visualize complexes of HPV-11 ori DNA bound by purified E2 protein. DNA containing only E2BS-2 showed a single E2 dimer bound. DNA containing E2BS-3 and E2BS-4 showed two side-by-side E2 dimers, while DNA containing E2BS-2, E2BS-3, and E2BS-4 exhibited a large disk/ring-shaped protein particle bound indicating that the DNA had been remodeled into a discrete complex, likely containing an E2 hexamer. With all four binding sites present, up to 27% of the DNA molecules were arranged into loops by E2, the majority of which spanned E2BS-1 and one of the other three sites. Studies of the dependence of looping on salt, ATP, and DTT using full length E2 and an E2 protein containing only the carboxyl-terminal DNA binding and protein dimerization domain suggest that looping is dependent on the N terminal domain as well as factors which may affect the manner in which E2 scans DNA for binding sites. The role of these structures in the modeling and regulation of the HPV-11 ori is discussed. PMID:18067922

Sim, Jeonggu; Ozgur, Sezgin; Lin, Biing Yuan; Yu, Jei-Hwa; Broker, Thomas R.; Chow, Louise T.; Griffith, Jack

2009-01-01

341

Overexpression of E2F1 Promotes Tumor Malignancy And Correlates with TNM Stages in Clear Cell Renal Cell Carcinoma  

PubMed Central

Background Transcription factor E2F1 exerts effects on many types of cancers. As an upstream regulator of a host of genes, E2F1 can trigger diverse aberrant transcription processes that may dominate malignancy. Clear cell renal cell carcinoma (ccRCC) is the most common subtype in renal cell carcinoma which displays high malignancy and has a shortage of biomarkers in clinics. Our study aimed to explore the function of E2F1 in ccRCC and its correlation with clinicopathological parameters. Methodology/Principle Findings Transcription factor E2F1 was mainly distributed in cancer cell nucleus and mRNA expression signi?cantly increased in 72 cases of clear cell renal cell carcinoma (ccRCC) tissues compared with adjacent non-cancerous kidney tissues (p<0.001). The protein expression was consistent with mRNA expression. Further analysis in 92 cases indicated that E2F1 mRNA level expression was associated with the tumor pathologic parameters embracing diameter, Fuhrman tumor grade, pT stage, TNM stage grouping and macrovascular infiltration (MAVI). These surgical specimens had high grade tumors accompanied with an elevated E2F1 expression. Moreover, E2F1 transfection was found to contribute significantly to cancer cell proliferation, migration and invasion in vitro. Conclusions/Significance Overexpression of E2F1 may be a key event in the local and vascular infiltration of ccRCC indicated by the activation of matrix metalloproteinase (MMP) 2 and MMP9. These findings highlighted the implication of E2F1’s function in the metastatic process. Furthermore, the clinical relevance of E2F1 in ccRCC pointed to a potential new therapeutic target. PMID:24023875

Fan, Yang; Ni, Dong; Zhang, Yu; Chen, Weihao; Zhang, Peng; Song, Erlin; Huang, Qingbo; Ai, Qing; Li, Hongzhao; Wang, Baojun; Zheng, Tao; Shi, Taoping; Zhang, Xu

2013-01-01

342

E2F-1 cooperates with topoisomerase II inhibition and DNA damage to selectively augment p53-independent apoptosis.  

PubMed Central

Mutations in the retinoblastoma (pRb) tumor suppressor pathway including its cyclin-cdk regulatory kinases, or cdk inhibitors, are a hallmark of most cancers and allow unrestrained E2F-1 transcription factor activity, which leads to unregulated G1-to-S-phase cell cycle progression. Moderate levels of E2F-1 overexpression are tolerated in interleukin 3 (IL-3)-dependent 32D.3 myeloid progenitor cells, yet this induces apoptosis when these cells are deprived of IL-3. However, when E2F activity is augmented by coexpression of its heterodimeric partner, DP-1, the effects of survival factors are abrogated. To determine whether enforced E2F-1 expression selectively sensitizes cells to cytotoxic agents, we examined the effects of chemotherapeutic agents and radiation used in cancer therapy. E2F-1 overexpression in the myeloid cells preferentially sensitized cells to apoptosis when they were treated with the topoisomerase II inhibitor etoposide. Although E2F-1 alone induces moderate levels of p53 and treatment with drugs markedly increased p53, the deleterious effects of etoposide in E2F-1-overexpressing cells were independent of p53 accumulation. Coexpression of Bcl-2 and E2F-1 in 32D.3 cells protected them from etoposide-mediated apoptosis. However, Bcl-2 also prevented apoptosis of these cells upon exposure to 5-fluorouracil and doxorubicin, which were also cytotoxic for control cells. Pretreating E2F-1-expressing cells with ICRF-193, a second topoisomerase II inhibitor that does not damage DNA, protected the cells from etoposide-induced apoptosis. However, ICRF-193 cooperated with DNA-damaging agents to induce apoptosis. Therefore, topoisomerase II inhibition and DNA damage can cooperate to selectively induce p53-independent apoptosis in cells that have unregulated E2F-1 activity resulting from mutations in the pRb pathway. PMID:9032231

Nip, J; Strom, D K; Fee, B E; Zambetti, G; Cleveland, J L; Hiebert, S W

1997-01-01

343

Secondary-electron emission mechanism of LiF film by (e,2e) spectroscopy  

NASA Astrophysics Data System (ADS)

Secondary-electron emission (SEE) from LiF films deposited on Si(0 0 1) surface was studied using time-of-flight two-electron coincidence spectroscopy. A set of energy-distribution curves (EDCs) of secondary electrons excited from a LiF film by electrons with energies in the range of 20-50 eV exhibits emission features at about 7 and 11 eV. The energy positions of these maxima do not depend on the incident energy. To reveal the origin of these features, each of the EDCs was spanned in the second dimension E2 using two-electron coincidence spectroscopy. Two-dimensional mapping of the energy sharing between correlated electrons shows that above 25 eV incident energy, one electron of the pair is preferentially emitted with E1=7.2±0.3 eV energy and the second one with energy E2=( Ep-23.3)±0.5 eV, where Ep is the incident electron energy. At about 30 eV incident energy, a second favoured emission energy of 10.9 ± 0.3 eV is observed. The unique capability of (e,2e) spectroscopy established the links between electron energy loss process and emission features in the EDCs. It is suggested that the mechanism of SEE from LiF film includes the excitation of two collective excitations with subsequent decay via electron ejection. It was shown that the mechanism of secondary emission from LiF film depends on the film thickness and its structure.

Samarin, S.; Berakdar, J.; Suvorova, A.; Artamonov, O. M.; Waterhouse, D. K.; Kirschner, J.; Williams, J. F.

2004-01-01

344

Bradykinin B2 receptor modulates renal prostaglandin E2 and nitric oxide.  

PubMed

Bradykinin and lys-bradykinin generated intrarenally appear to be important renal paracrine hormones. However, the renal effects of endogenously generated bradykinin are still not clearly defined. In this study, we measured acute changes in renal excretory and hemodynamic functions and renal cortical interstitial fluid levels of bradykinin, prostaglandin E2, and cGMP in response to an acute intrarenal arterial infusion of the bradykinin B2 receptor antagonist Hoe 140 (icatibant), cyclooxygenase inhibitor indomethacin, or nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) given individually or combined in uninephrectomized, conscious dogs (n=10) in low sodium balance. Icatibant caused a significant decrease in urine flow, urinary sodium excretion, and renal plasma flow rate (each P<.001). Glomerular filtration rate did not change during icatibant administration. Icatibant produced an unexpected large increase in renal interstitial fluid bradykinin (P<.0001) while decreasing renal interstitial fluid prostaglandin E2 and cGMP (each P<.001). Both indomethacin and L-NMMA when given individually caused significant antidiuresis and antinatriuresis and decreased renal blood flow (each P<.001). Glomerular filtration rate decreased during L-NMMA administration (P<.001) and did not change during indomethacin administration. Combined administration of icatibant and indomethacin or L-NMMA caused significant decreases in renal excretory and hemodynamic functions, which were not different from changes observed with icatibant alone. The failure of icatibant to change renal function after inhibition of cyclooxygenase and nitric oxide synthase activity suggests that the effects of kinin B2 receptor are mediated by intrarenal prostaglandin E2 and nitric oxide generation. The increase in renal interstitial fluid bradykinin during icatibant requires further study of possible alterations in kinin synthesis, degradation, or clearance as a result of B2 receptor blockade. PMID:9052892

Siragy, H M; Jaffa, A A; Margolius, H S

1997-03-01

345

Comparative analysis of the replicon regions of eleven ColE2-related plasmids.  

PubMed Central

The incA gene product of ColE2-P9 and ColE3-CA38 plasmids is an antisense RNA that regulates the production of the plasmid-coded Rep protein essential for replication. The Rep protein specifically binds to the origin and synthesizes a unique primer RNA at the origin. The IncB incompatibility is due to competition for the Rep protein among the origins of the same binding specificity. We localized the regions sufficient for autonomous replication of 15 ColE plasmids related to ColE2-P9 and ColE3-CA38 (ColE2-related plasmids), analyzed their incompatibility properties, and determined the nucleotide sequences of the replicon regions of 9 representative plasmids. The results suggest that all of these plasmids share common mechanisms for initiation of DNA replication and its control. Five IncA specificity types, 4 IncB specificity types, and 9 of the 20 possible combinations of the IncA and IncB types were found. The specificity of interaction of the Rep proteins and the origins might be determined by insertion or deletion of single nucleotides and substitution of several nucleotides at specific sites in the origins and by apparently corresponding insertion or deletion and substitution of amino acid sequences at specific regions in the C-terminal portions of the Rep proteins. For plasmids of four IncA specificity types, the nine-nucleotide sequences at the loop regions of the stem-loop structures of antisense RNAs are identical, suggesting an evolutionary significance of the sequence. The mosaic structures of the replicon regions with homologous and nonhomologous segments suggest that some of them were generated by exchanging functional parts through homologous recombination. PMID:7525540

Hiraga, S; Sugiyama, T; Itoh, T

1994-01-01

346

Eugenol triggers apoptosis in breast cancer cells through E2F1/survivin down-regulation  

PubMed Central

Background Breast cancer is a major health problem that threatens the lives of millions of women worldwide each year. Most of the chemotherapeutic agents that are currently used to treat this complex disease are highly toxic with long-term side effects. Therefore, novel generation of anti-cancer drugs with higher efficiency and specificity are urgently needed. Methods Breast cancer cell lines were treated with eugenol and cytotoxicity was measured using the WST-1 reagent, while propidium iodide/annexinV associated with flow cytometry was utilized in order to determine the induced cell death pathway. The effect of eugenol on apoptotic and pro-carcinogenic proteins, both in vitro and in tumor xenografts was assessed by immunoblotting. While RT-PCR was used to determine eugenol effect on the E2F1 and survivin mRNA levels. In addition, we tested the effect of eugenol on cell proliferation using the real-time cell electronic sensing system. Results Eugenol at low dose (2 ?M) has specific toxicity against different breast cancer cells. This killing effect was mediated mainly through inducing the internal apoptotic pathway and strong down-regulation of E2F1 and its downstream antiapoptosis target survivin, independently of the status of p53 and ER?. Eugenol inhibited also several other breast cancer related oncogenes, such as NF-?B and cyclin D1. Moreover, eugenol up-regulated the versatile cyclin-dependent kinase inhibitor p21WAF1 protein, and inhibited the proliferation of breast cancer cells in a p53-independent manner. Importantly, these anti-proliferative and pro-apoptotic effects were also observed in vivo in xenografted human breast tumors. Conclusion Eugenol exhibits anti-breast cancer properties both in vitro and in vivo, indicating that it could be used to consolidate the adjuvant treatment of breast cancer through targeting the E2F1/survivin pathway, especially for the less responsive triple-negative subtype of the disease. PMID:24330704

2013-01-01

347

{(E)-2-[3-(Dimethyl­ammonio)propyl­iminometh­yl]phenolato}diiodidozinc(II)  

PubMed Central

The title complex, [ZnI2(C12H18N2O)], is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base (E)-2-[(3-dimethyl­amino­propyl­imino)meth­yl]phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand, and by two iodide ions in a tetra­hedral coordination geometry. In the crystal structure, mol­ecules are linked through inter­molecular N—H?O hydrogen bonds, forming chains running along the b axis. PMID:21203068

Zhu, Xue-Wen; Yang, Xu-Zhao

2008-01-01

348

On-orbit calibration of soft X-ray detector on Chang'E-2 satellite  

E-print Network

X-ray spectrometer is one of the satellite payloads on Chang'E-2 satellite. The soft X-ray detector is one of the device on X-ray spectrometer which is designed to detect the major rock-forming elements within 0.5-10keV range on lunar surface. In this paper, energy linearity and energy resolution calibration is done using a weak Fe55 source, while temperature and time effect is considered not take big error. The total uncertainty is estimated to be within 5% after correction.

Xiao, Hong; Wang, Huanyu; Cui, Xingzhu; Guo, Dongya

2015-01-01

349

X-ray Spectroscopy of E2 and M3 Transitions in Ni-like W  

SciTech Connect

The electric quadrupole (E2) and magnetic octupole (M3) ground state transitions in Ni-like W{sup 46+} have been measured using high-resolution crystal spectroscopy at the Livermore electron beam ion trap facility. The lines fall in the soft x-ray region near 7.93 {angstrom} and were originally observed as an unresolved feature in tokamak plasmas. Using flat ADP and quartz crystals the wavelengths, intensities, and polarizations of the two lines have been measured for various electron beam energies and compared to intensity and polarization calculations performed using the Flexible Atomic Code (FAC).

Clementson, J; Beiersdorfer, P; Gu, M F

2009-11-09

350

Cholecalciferol Induces Prostaglandin E2 Biosynthesis and Transglutaminase Activity in Human Keratinocytes  

Microsoft Academic Search

In this study, we examined the effects of cholecalciferol, a primary keratinocyte metabolite and precursor of the hydroxylated form of vitamin D3, 1?,25-dihydroxyvitamin D3[1?,25(OH)2D3[, on prostaglandin E2 (PGE2) production in human keratinocytes by examining its respective effects on cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and cytosolic phospholipase A2 (cPLA2) expression, the rate-limiting enzymes regulating PGE2 biosynthesis and differentiation of keratinocytes. Cholecalciferol induced

Takuro Kanekura; Stanley J. F. Laulederkind; Kanyawim Kirtikara; Sarita Goorha; Leslie R. Ballou

1998-01-01

351

Valence Shell Ionization Spectra of Propane by (e, 2e) Spectroscopy  

NASA Astrophysics Data System (ADS)

The measurements of the valence shell ionisation energy spectra (6-32 eV) for propane (C3H8) by high resolution (?E = 0.9 eV and ?p = 0.1 a.u.) (e, 2e) spectrometer at impact energy of 1200 eV plus binding energy and symmetric noncoplanar kinematics are reported. The spectrum is consistent with a single particle picture of ionization from each of the seven outer-valence orbitals and the three inner-valence orbitals. The ionization energies are in agreement with published photoelectron spectroscopy data.

Pang, Wen-ning; Zhang, Wen-xin; Gao, Nai-fei; Shang, Ren-cheng; Deng, Jing-kang; Chen, Xue-jun

1998-09-01

352

Pan/E2A expression precedes immunoglobulin heavy-chain expression during B lymphopoiesis in nontransformed cells, and Pan/E2A proteins are not detected in myeloid cells.  

PubMed

A newly developed rat long-term bone marrow culture system was used to study the role of Pan/E2A basic helix-loop-helix transcription factors during B-cell development. In this system, B-lymphocyte progenitors actively differentiate into mature B cells. Monoclonal (Yae) and polyclonal (anti-Pan) antibodies were employed to characterize the expression of Pan proteins by Western blot assay during hematopoiesis and to examine the components of immunoglobulin heavy-chain gene enhancer element-binding species by electrophoretic mobility shift assay. During B-cell development, the appearance of Pan/E2A proteins preceded the expression of immunoglobulin heavy-chain protein. A Pan-containing immunoglobulin heavy-chain enhancer element (mu E5)-binding species (BCF1), composed of immunoreactive Pan-1/E47 but not Pan-2/E12, was observed concomitantly with the detection of Pan/E2A proteins. In addition to BCF1, other mu E5-binding species were detected which were not recognized by the Yae antibody. Two of these species were present in primary B-lymphocyte and myeloid cultures and were recognized by an anti-upstream stimulatory factor antiserum. Although Pan/E2A proteins have been proposed to be ubiquitous, Pan/E2A proteins were not detected in primary myeloid cultures composed mainly of granulocytes and macrophages or in the macrophage cell line J774. The absence of Pan/E2A proteins in differentiated myeloid cells correlated with low steady-state levels of Pan/E2A RNA. However, Pan/E2A proteins were present in a promyeloid cell line, 32DCL3, suggesting that extinction of Pan/E2A expression may play a role in myelopoiesis. PMID:8196647

Jacobs, Y; Xin, X Q; Dorshkind, K; Nelson, C

1994-06-01

353

Targeted gene mutation of E2F1 evokes age-dependent synaptic disruption and behavioral deficits.  

PubMed

Aberrant expression and activation of the cell cycle protein E2F1 in neurons has been implicated in many neurodegenerative diseases. As a transcription factor regulating G1 to S phase progression in proliferative cells, E2F1 is often up-regulated and activated in models of neuronal death. However, despite its well-studied functions in neuronal death, little is known regarding the role of E2F1 in the mature brain. In this study, we used a combined approach to study the effect of E2F1 gene disruption on mouse behavior and brain biochemistry. We identified significant age-dependent olfactory and memory-related deficits in E2f1 mutant mice. In addition, we found that E2F1 exhibits punctated staining and localizes closely to the synapse. Furthermore, we found a mirroring age-dependent loss of post-synaptic protein-95 in the hippocampus and olfactory bulb as well as a global loss of several other synaptic proteins. Coincidently, E2F1 expression is significantly elevated at the ages, in which behavioral and synaptic perturbations were observed. Finally, we show that deficits in adult neurogenesis persist late in aged E2f1 mutant mice which may partially contribute to the behavior phenotypes. Taken together, our data suggest that the disruption of E2F1 function leads to specific age-dependent behavioral deficits and synaptic perturbations. E2F1 is a transcription factor regulating cell cycle progression and apoptosis. Although E2F1 dysregulation under toxic conditions can lead to neuronal death, little is known about its physiologic activity in the healthy brain. Here, we report significant age-dependent olfactory and memory deficits in mice with dysfunctional E2F1. Coincident with these behavioral changes, we also found age-matched synaptic disruption and persisting reduction in adult neurogenesis. Our study demonstrates that E2F1 contributes to physiologic brain structure and function. PMID:24460902

Ting, Jenhao H; Marks, David R; Schleidt, Stephanie S; Wu, Joanna N; Zyskind, Jacob W; Lindl, Kathryn A; Blendy, Julie A; Pierce, R Christopher; Jordan-Sciutto, Kelly L

2014-06-01

354

The histone demethylase LSD1 is required for estrogen-dependent S100A7 gene expression in human breast cancer cells  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer S100A7 gene is up-regulated in response to estrogen in breast cancer cells. Black-Right-Pointing-Pointer Histone demethylase LSD1 can associate physically with S100A7 gene promoters. Black-Right-Pointing-Pointer E2-induced S100A7 expression requires the enzymatic activity of LSD1. Black-Right-Pointing-Pointer S100A7 inhibits cell proliferation, implying its tumor suppressor-like function. -- Abstract: S100A7, a member of S100 calcium binding protein family, is highly associated with breast cancer. However, the molecular mechanism of S100A7 regulation remains unclear. Here we show that long-term treatment with estradiol stimulated S100A7 expression in MCF7 breast cancer cells at both the transcriptional and translational levels. Both treatment with a histone demethylase LSD1 inhibitor and shRNA-based knockdown of LSD1 expression significantly decreased 17{beta}-estradiol (E2)-induced S100A7 expression. These reduced E2-mediated S100A7 expression are rescued by the overexpressed wild-type LSD1 but not by its catalytically inactive mutant. Our data showed in vivo association of LSD1 with S100A7 promoters, confirming the potential role of LSD1 in regulating S100A7 expression. S100A7 knockdown increased both normal cell growth and estrogen-induced cell proliferation, suggesting a negative influence by S100A7 on the growth of cancer cells. Together, our data suggest that estrogen-induced S100A7 expression mediated by the histone demethylase LSD1 may downregulate breast cancer cell proliferation, implying a potential tumor suppressor-like function for S100A7.

Yu, Seung Eun [Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of) [Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Yonsei Biomolecule Research Initiative, Yonsei University, Seoul 120-749 (Korea, Republic of); Jang, Yeun Kyu, E-mail: ykjang@yonsei.ac.kr [Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Yonsei Biomolecule Research Initiative, Yonsei University, Seoul 120-749 (Korea, Republic of)

2012-10-19

355

Identification and transcriptional modulation of the largemouth bass, Micropterus salmoides, vitellogenin receptor during oocyte development by insulin and sex steroids.  

PubMed

Fish vitellogenin synthesized and released from the liver of oviparous animals is taken up into oocytes by the vitellogenin receptor. This is an essential process in providing nutrient yolk to developing embryos to ensure successful reproduction. Here we disclose the full length vtgr cDNA sequence for largemouth bass (LMB) that reveals greater than 90% sequence homology with other fish vtgr sequences. We classify LMB Vtgr as a member of the low density lipoprotein receptor superfamily based on conserved domains and categorize as the short variant that is devoid of the O-glycan segment. Phylogenetic analysis places LMB Vtgr sequence into a well-supported monophyletic group of fish Vtgr. Real-time PCR showed that the greatest levels of LMB vtgr mRNA expression occurred in previtellogenic ovarian tissues. In addition, we reveal the effects of insulin, 17beta-estradiol (E(2)), and 11-ketotestosterone (11-KT) in modulation of vtgr, esr, and ar mRNAs in previtellogenic oocytes. Insulin increased vtgr expression levels in follicles ex vivo while exposure to E(2) or 11-KT did not result in modulation of expression. However, both steroids were able to repress insulin-induced vtgr transcript levels. Coexposure with insulin and E(2) or of insulin and 11-KT increased ovarian esr2b and ar mRNA levels, respectively, which suggest a role for these nuclear receptors in insulin-mediated signaling pathways. These data provide the first evidence for the ordered stage-specific expression of LMB vtgr during the normal reproductive process and the hormonal influence of insulin and sex steroids on controlling vtgr transcript levels in ovarian tissues. PMID:22786822

Dominguez, Gustavo A; Quattro, Joseph M; Denslow, Nancy D; Kroll, Kevin J; Prucha, Melinda S; Porak, Wesley F; Grier, Harry J; Sabo-Attwood, Tara L

2012-09-01

356

Role of receptor complexes in the extranuclear actions of estrogen receptor alpha in breast cancer.  

PubMed

Our recent studies have examined the role of various receptor complexes in the mediation of rapid, extranuclear effects of estradiol. This review describes 17beta-estradiol (E2)-initiated extranuclear signaling pathways, which involve the insulin-like growth factor 1 receptor (IGF-1R) and epidermal growth factor receptor (EGFR) and result in the activation of several kinase cascades. The biologic results of these effects are the enhancement of cell proliferation and diminution of programmed cell death (apoptosis). Until recently, most studies assigned priority to the nuclear transcriptional actions of estrogen receptor alpha (ER alpha). Present investigative emphasis focuses on the additional importance of ER alpha residing in or near the plasma membrane. A small fraction of ER alpha is associated with the cell membrane and mediates the rapid effects of E2. Unlike classical growth factor receptors, such as IGF-1R and EGFR, ER alpha has no transmembrane and kinase domains and is known to initiate E2 rapid signals by forming protein/protein complexes with many signaling molecules. Our recent studies demonstrate that the IGF-1R is involved in tethering ER alpha to the plasma membrane, in activating the EGFR, and in the initiation of mitogen-activated protein kinase and phosphoinositide 3-kinase signaling. The formation of a multi-protein complex containing these receptors as well as adaptor proteins is a critical step in this process. A full understanding of the mechanisms underlying these relationships with the ultimate aim of abrogating specific steps, should lead to more targeted strategies for treatment of hormone-dependent breast cancer. PMID:17259556

Song, Robert X-D; Fan, Ping; Yue, Wei; Chen, Yucai; Santen, Richard J

2006-12-01

357

Estrogen and selective estrogen receptor modulators exert neuroprotective effects and stimulate the expression of selective Alzheimer's disease indicator-1, a recently discovered antiapoptotic gene, in human neuroblast long-term cell cultures.  

PubMed

According to the fact that Alzheimer's disease (AD) is more common in postmenopausal women, estrogen treatment has been proposed. Experimental studies, still mostly performed using animal models, demonstrated that estrogen exerts neuroprotective effects. We previously established neuroblast long-term cell cultures from human fetal olfactory epithelium. In the present study, we addressed the role of estrogen in these unique human cells, which express both the estrogen receptor (ER)-alpha and ERbeta. We found that 17beta-estradiol (17betaE(2)) and the selective estrogen receptor modulators (SERMs) raloxifene and tamoxifen exerted neuroprotective effects, which were independent of cell proliferation, by increasing resistance against beta-amyloid-induced toxicity, with the exception of the highest concentrations of raloxifene (10 and 100 nm). In addition, 17betaE(2) exposure protected from oxidative stress, reduced apoptosis, and increased the expression of the catalytic subunit of telomerase. Furthermore, we evaluated by quantitative real-time RT-PCR whether estrogen/SERMs modulate the expression of the recently discovered seladin-1 (selective AD indicator-1) gene, which exerts neuroprotective effects and is down-regulated in AD-vulnerable brain regions. 17betaE(2) (100 pm to 100 nm) and SERMs (1 nm) significantly increased the amount of seladin-1 mRNA. Conversely, 10 and 100 nm raloxifene reduced the expression of seladin-1. The effect of estrogen appears mainly mediated by ERalpha because the selective ERalpha agonist propylpyrazole-triol determined a much greater increase of seladin-1 expression than the ERbeta agonist diarylpropionitrile. Our results add new evidence, using human neuronal cells, for a beneficial effect of estrogen in preventing neurodegenerative diseases and suggest for the first time that seladin-1 may mediate this effect. PMID:15585566

Benvenuti, Susanna; Luciani, Paola; Vannelli, Gabriella Barbara; Gelmini, Stefania; Franceschi, Elisa; Serio, Mario; Peri, Alessandro

2005-03-01

358

Effects of culture conditions on estrogen-mediated hepatic in vitro gene expression and correlation to in vivo responses  

SciTech Connect

Refinement of in vitro systems for predictive toxicology is important in order to develop high-throughput early toxicity screening assays and to minimize animal testing studies. This study assesses the ability of mouse Hepa-1c1c7 hepatoma cell model under differing culture conditions to predict in vivo estrogen-induced hepatic gene expression changes. Custom mouse cDNA microarrays were used to compare Hepa-1c1c7 temporal gene expression profiles treated with 10 nM 17{beta}-estradiol (E2) in serum-free and charcoal-stripped serum supplemented media at 1, 2, 4, 8, 12, and 24 h. Stripped serum supplemented media increased the number gene expression changes and overall responsiveness likely due to the presence of serum factors supporting proliferation and mitochondrial activity. Data from both experiments were compared to a gene expression time course study examining the hepatic effects of 100 {mu}g/kg 17{alpha}-ethynyl estradiol (EE) in C57BL/6 mice at 2, 4, 8, 12, 18, and 24 h. Only 18 genes overlapped between the serum-free and in vivo studies, whereas 238 genes were in common between Hepa-1c1c7 cells in stripped serum data and C57BL/6 liver samples. Stripped serum cultured cells exhibited E2-elicited gene expression changes associated with proliferation, cytoskeletal re-organization, cholesterol uptake and synthesis, increased fatty acid {beta}-oxidation, and oxidative stress, which correlated with in vivo hepatic responses. These results demonstrate that E2 treatment of Hepa-1c1c7 cells in serum supplemented media modulate responses in selected pathways which appropriately model estrogen-elicited in vivo hepatic responses.

Fong, C.J. [Department of Biochemistry and Molecular Biology, National Food Safety and Toxicology Center and Center for Integrative Toxicology, Michigan State University, 501 Biochemistry Building, Wilson Road, East Lansing, MI 48824-1319 (United States); Burgoon, L.D. [Department of Biochemistry and Molecular Biology, National Food Safety and Toxicology Center and Center for Integrative Toxicology, Michigan State University, 501 Biochemistry Building, Wilson Road, East Lansing, MI 48824-1319 (United States); Zacharewski, T.R. [Department of Biochemistry and Molecular Biology, National Food Safety and Toxicology Center and Center for Integrative Toxicology, Michigan State University, 501 Biochemistry Building, Wilson Road, East Lansing, MI 48824-1319 (United States)]. E-mail: tzachare@msu.edu

2006-08-15

359

Effect of glutamate and somatostatin-14 on basal and cAMP-stimulated steroidogenesis by rainbow trout (Oncorhynchus mykiss) ovarian follicles, in vitro.  

PubMed

The effects of glutamate and somatostatin-14 (SRIF) on the in vitro basal and cAMP-stimulated steroid production of mid-vitellogenic rainbow trout (Oncorhynchus mykiss) ovarian follicles were investigated. cAMP-stimulation was achieved by the addition of the adenylyl cyclase activator, forskolin (FS), or a membrane permeate cAMP agonist, 8-bromo-cAMP (BA), to the incubation medium. Testosterone (T) and 17beta-estradiol (E(2)) secretion was measured using radioimmunoassay. Solid phase extraction (SPE) was used to measure the relative formation of unconjugated and conjugated steroids, and high performance liquid chromatography (HPLC) was used to examine the steroid metabolites formed from the metabolism of a tritium labelled precursor, pregnenolone (P(5)). The accumulations of T and E(2) in the medium were suppressed in the presence of the glutamate agonists, N-methyl-d,l-aspartate (NMA) or l-glutamic acid (GA), and by the presence of SRIF. The suppression was evident for both basal and cAMP-stimulated steroidogenesis except for T concentrations of GA treatments following basal steroidogenesis, when there were no treatment effects. No significant effects of treatment on conjugated:unconjugated steroid ratios were found. For all treatments E(2) was the major end product steroid synthesized from P(5), and the steroid profiles were similar except for trace amounts of radiolabelled androgens in the medium following cAMP-stimulated steroidogenesis that were not present following basal steroidogenesis. The findings suggest that glutamate and SRIF reduce end point steroid production, possibly by reducing P(5) production. However, since the inhibitory affect was found for basal and cAMP-stimulated steroidogenesis, the response does not appear to be due to the inhibition of cAMP synthesis. PMID:15763520

Leatherland, John F; Lin, Lucy; Renaud, Rick

2005-04-01

360

Identification and Transcriptional Modulation of the Largemouth Bass, Micropterus salmoides, Vitellogenin Receptor During Oocyte Development by Insulin and Sex Steroids1  

PubMed Central

ABSTRACT Fish vitellogenin synthesized and released from the liver of oviparous animals is taken up into oocytes by the vitellogenin receptor. This is an essential process in providing nutrient yolk to developing embryos to ensure successful reproduction. Here we disclose the full length vtgr cDNA sequence for largemouth bass (LMB) that reveals greater than 90% sequence homology with other fish vtgr sequences. We classify LMB Vtgr as a member of the low density lipoprotein receptor superfamily based on conserved domains and categorize as the short variant that is devoid of the O-glycan segment. Phylogenetic analysis places LMB Vtgr sequence into a well-supported monophyletic group of fish Vtgr. Real-time PCR showed that the greatest levels of LMB vtgr mRNA expression occurred in previtellogenic ovarian tissues. In addition, we reveal the effects of insulin, 17beta-estradiol (E2), and 11-ketotestosterone (11-KT) in modulation of vtgr, esr, and ar mRNAs in previtellogenic oocytes. Insulin increased vtgr expression levels in follicles ex vivo while exposure to E2 or 11-KT did not result in modulation of expression. However, both steroids were able to repress insulin-induced vtgr transcript levels. Coexposure with insulin and E2 or of insulin and 11-KT increased ovarian esr2b and ar mRNA levels, respectively, which suggest a role for these nuclear receptors in insulin-mediated signaling pathways. These data provide the first evidence for the ordered stage-specific expression of LMB vtgr during the normal reproductive process and the hormonal influence of insulin and sex steroids on controlling vtgr transcript levels in ovarian tissues. PMID:22786822

Dominguez, Gustavo A.; Quattro, Joseph M.; Denslow, Nancy D.; Kroll, Kevin J.; Prucha, Melinda S.; Porak, Wesley F.; Grier, Harry J.; Sabo-Attwood, Tara L.

2012-01-01

361

E2F-Dependent Histone Acetylation and Recruitment of the Tip60 Acetyltransferase Complex to Chromatin in Late G1  

Microsoft Academic Search

E2F proteins can either activate or repress transcription. Following mitogenic stimulation, repressive E2F4-p130-histone deacetylase complexes dissociate from, while activating species (E2F1, -2, and -3) associate with, target promoters. Histones H3 and H4 simultaneously become hyperacetylated, but it remains unclear whether this is a prerequisite or a consequence of E2F binding. Here, we show that activating E2F species are required for

Stefan Taubert; Chiara Gorrini; Scott R. Frank; Tiziana Parisi; Miriam Fuchs; Ho-Man Chan; David M. Livingston; Bruno Amati

2004-01-01

362

New Insights of Asteroid 4179 Toutatis Using China Chang'e-2 Close Flyby Optical Measurements  

NASA Astrophysics Data System (ADS)

The mysteries of near-Earth asteroid 4179 Toutatis have been more comprehensively unveiled by analyzing the optical images taken during the Chang'e-2 flyby in 2012. Compared with previous works, this paper concentrates on the photogrammetric relation between the Chang'e-2 spacecraft and Toutatis and the imaging shadow effect during the flyby. Accurate models of imaging and optical measurements are developed to study Toutatis's dimensions and rotational state at the time of imaging. As the illumination study shows, the shadowed region perpendicular to the long axis accounts for 27.78% of the Toutatis images, while the long axis of the body is fully captured. With a compensation on the shadow effect, the optical measurements reveal that Toutatis's long axis is 4354 ± 56 m, the maximum length is 4391 ± 56 m, and the spatial orientation described with the angles of direction cosine during the flyby is (126.°13 ± 0.°29, 122.°98 ± 0.°21, 126.°63 ± 0.°46). Furthermore, a new triaxial ellipsoid of 4354 × 1835 × 2216 m and a volume of 7.5158 km3 are proposed based on the previous Toutatis shape model. The effectiveness of the proposed method is validated, since typical features such as the neck and endpoints agree well with the results simultaneously observed by the ground radar. Moreover, it also potentially provides a feasible approach to precisely calculate the spin period of Toutatis.

Bu, Yanlong; Tang, Geshi; Di, KaiChang; Fa, Wenzhe; Hu, Tianjiang; Ding, Chibiao; Xu, Bin; Liu, Bin; Cao, Jianfeng; Hu, Songjie; Yang, Cheng; Liu, Chuankai

2015-01-01

363

M1 and E2 strength functions of barium from thermal neutron capture  

NASA Astrophysics Data System (ADS)

Thermal-neutron-capture gamma rays from natural barium have been studied at the tangential facility of a reactor using a pair spectrometer. Precise transition, level, and neutron separation energies of six isotopes of barium are inferred. The separation energies are Sn(133Ba)=7189.96+/-0.36, Sn(135Ba)=6972.21+/-0.18, Sn(136Ba)=9107.84+/-0.04, Sn(137Ba)=6905.78+/-0.03, Sn(138Ba) =8611.75 +/-0.04, and Sn(139Ba)=4723.44+/-0.04 keV. The M1 strength functions of 136Ba and 138Ba are found to be (27+/-7)×10-9 and (5.7+/-2.1)×10-9 MeV-3, the former being much higher and the latter much lower than the global average of 18×10-9 MeV-3. The average B(E2)?¯ of 136,138Ba observed is 53+/-35 e2fm4MeV-1, which is 0.6+/-0.4 times the value predicted by the Axel-Brink hypothesis.

Islam, M. A.; Kennett, T. J.; Prestwich, W. V.

1990-07-01

364

Structural Code for DNA Recognition Revealed in Crystal Structures of Papillomavirus E2-DNA Targets  

NASA Astrophysics Data System (ADS)

Transcriptional regulation in papillomaviruses depends on sequence-specific binding of the regulatory protein E2 to several sites in the viral genome. Crystal structures of bovine papillomavirus E2 DNA targets reveal a conformational variant of B-DNA characterized by a roll-induced writhe and helical repeat of 10.5 bp per turn. A comparison between the free and the protein-bound DNA demonstrates that the intrinsic structure of the DNA regions contacted directly by the protein and the deformability of the DNA region that is not contacted by the protein are critical for sequence-specific protein/DNA recognition and hence for gene-regulatory signals in the viral system. We show that the selection of dinucleotide or longer segments with appropriate conformational characteristics, when positioned at correct intervals along the DNA helix, can constitute a structural code for DNA recognition by regulatory proteins. This structural code facilitates the formation of a complementary protein-DNA interface that can be further specified by hydrogen bonds and nonpolar interactions between the protein amino acids and the DNA bases.

Rozenberg, Haim; Rabinovich, Dov; Frolow, Felix; Hegde, Rashmi S.; Shakked, Zippora

1998-12-01

365

Detection of ethylene glycol - toward W51/e2 and G34.3+0.02  

NASA Astrophysics Data System (ADS)

Ethylene glycol (HOCH2CH2OH), also commenly known as antifreeze, is the reduced alcohol version of glycolaldehyde (CH2OHCHO). Glycoladehyde - the simplest possible aldehyde sugar (Marstokk and Møllendal 1973) - is the first intermediate step in the path toward forming more complex and biologically relevant molecules through the the formose reaction, which begins with formaldehyde (H2CO) and ends with the formation of sugars and ultimately ribose, the backbone of RNA (e.g., Larralde et al. 1995). The presence of glycolaldehyde is therefore an important indication that processes leading to biologically relevant molecules are taking place. It is however, still unclear as to how glycolaldehyde and ethylene glycol are formed in the ISM. It has been proposed that they share a common formation pathway through UV-irradiation of methanol (CH3OH) ices mixed with CO (Öberg et al. 2009). So far, ethylene glycol, in its lower energy con-former (g’Ga(CH2OH)2), has been detected toward SgrB2 (N) by Hollis et al. (2002), tentatively toward IRAS 16293-2422 (Jørgensen et al. 2012) and marginally by Kalenskii and Johansson (2010) toward W51 e1/e2. Here we present a firm detection of ethylene glycol toward W51/e2 as well as a first detection toward G34.3+0.02 at 1mm and 3mm using the IRAM 30m telescope.

Lykke, Julie M.; Favre, Cécile

2014-07-01

366

Inhibitors of microsomal prostaglandin E2 synthase-1 enzyme as emerging anti-inflammatory candidates.  

PubMed

Cyclooxygenases (COX-1 and COX-2) catalyze the conversion of arachidonic acid (AA) into PGH2 that is further metabolized by terminal prostaglandin (PG) synthases into biologically active PGs, for example, prostaglandin E2 (PGE2), prostacyclin I2 (PGI2), thromboxane A2 (TXA2), prostaglandin D2 (PGD2), and prostaglandin F2 alpha (PGF2?). Among them, PGE2 is a widely distributed PG in the human body, and an important mediator of inflammatory processes. The successful modulation of this PG provides a beneficial strategy for the potential anti-inflammatory therapy. For instance, nonsteroidal anti-inflammatory agents (NSAIDs), both classical nonselective (cNSAIDs) and the selective COX-2 inhibitors (coxibs) attenuate the generation of PGH2 from AA that in turn reduces the synthesis of PGE2 and modifies the inflammatory conditions. However, the long-term use of these agents causes severe side effects due to the nonselective inhibition of other PGs, such as PGI2 and TXA2, etc. Microsomal prostaglandin E2 synthase-1 (mPGES-1), a downstream PG synthase, specifically catalyzes the biosynthesis of COX-2-derived PGE2 from PGH2, and describes itself as a valuable therapeutic target for the treatment of acute and chronic inflammatory disease conditions. Therefore, the small molecule inhibitors of mPGES-1 would serve as a beneficial anti-inflammatory therapy, with reduced side effects that are usually associated with the nonselective inhibition of PG biosynthesis. PMID:25019142

Bahia, Malkeet Singh; Katare, Yogesh Kumar; Silakari, Om; Vyas, Bhawna; Silakari, Pragati

2014-07-01

367

Regulation of DNA methyltransferase 1 by the pRb/E2F1 pathway.  

PubMed

Tumor suppressor gene silencing by DNA hypermethylation contributes to tumorigenesis in many tumor types. This aberrant methylation may be due to increased expression and activity of DNA methyltransferases, which catalyze the transfer of methyl groups from S-adenosylmethionine to cytosines in CpG dinucleotides. Elevated expression of the maintenance DNA methyltransferase, DNA methyltransferase 1 (DNMT-1), has been shown in carcinomas of the colon, lung, liver, and prostate. Based on the nearly ubiquitous alterations of both DNA methylation and the retinoblastoma protein (pRb) pathway found in human cancer, we investigated a potential regulatory pathway linking the two alterations in murine and human prostate epithelial cells. Analysis of DNA methyltransferase levels in Rb-/- murine prostate epithelial cell lines revealed elevated Dnmt-1 levels. Genomic DNA sequence analysis identified conserved E2F consensus binding sites in proximity to the transcription initiation points of murine and human Dnmt-1. Furthermore, the Dnmt-1 promoter was shown to be regulated by the pRb/E2F pathway in murine and human cell lines of epithelial and fibroblast origin. In the absence of pRb, Dnmt-1 transcripts exhibited aberrant cell cycle regulation and Rb-/- cells showed aberrant methylation of the paternally expressed gene 3 (Peg3) tumor suppressor gene. These findings show a link between inactivation of the pRb pathway and induction of DNA hypermethylation of CpG island-containing genes in tumorigenesis. PMID:15867357

McCabe, Michael T; Davis, Joanne N; Day, Mark L

2005-05-01

368

Anti-oncogenic MicroRNA-203 Induces Senescence by Targeting E2F3 Protein in Human Melanoma Cells  

PubMed Central

MicroRNAs regulate gene expression by repressing translation or directing sequence-specific degradation of their complementary mRNA. We recently reported that miR-203 is down-regulated, and its exogenous expression inhibits cell growth in canine oral malignant melanoma tissue specimens as well as in canine and human malignant melanoma cells. A microRNA target database predicted E2F3 and ZBP-89 as putative targets of microRNA-203 (miR-203). The expression levels of E2F3a, E2F3b, and ZBP-89 were markedly up-regulated in human malignant melanoma Mewo cells compared with those in human epidermal melanocytes. miR-203 significantly suppressed the luciferase activity of reporter plasmids containing the 3?-UTR sequence of either E2F3 or ZBP-89 complementary to miR-203. The ectopic expression of miR-203 in melanoma cells reduced the levels of E2F3a, E2F3b, and ZBP-89 protein expression. At the same time, miR-203 induced cell cycle arrest and senescence phenotypes, such as elevated expression of hypophosphorylated retinoblastoma and other markers for senescence. Silencing of E2F3, but not of ZBP-89, inhibited cell growth and induced cell cycle arrest and senescence. These results demonstrate a novel role for miR-203 as a tumor suppressor acting by inducing senescence in melanoma cells. PMID:22354972

Noguchi, Shunsuke; Mori, Takashi; Otsuka, Yusami; Yamada, Nami; Yasui, Yuki; Iwasaki, Junya; Kumazaki, Minami; Maruo, Kohji; Akao, Yukihiro

2012-01-01

369

ROR? binds to E2F1 to inhibit cell proliferation and regulate mammary gland branching morphogenesis.  

PubMed

Retinoic acid receptor-related orphan nuclear receptor alpha (ROR?) is a potent tumor suppressor that reduces cell proliferation and inhibits tumor growth. However, the molecular mechanism by which it inhibits cell proliferation remains unknown. We demonstrate a noncanonical nuclear receptor pathway in which ROR? binds to E2F1 to inhibit cell cycle progression. We showed that ROR? bound to the heptad repeat and marked box region of E2F1 and suppressed E2F1-regulated transcription in epithelial cells. Binding of ROR? inhibited E2F1 acetylation and its DNA-binding activity by recruiting histone deacetylase 1 (HDAC1) to the protein complexes. Knockdown of HDAC1 or inhibition of HDAC activity at least partially rescued transcription factor activity of E2F1 that was repressed by ROR?. Importantly, ROR? levels were increased in mammary ducts compared to terminal end buds and inversely correlated with expression of E2F1 target genes and cell proliferation. Silencing ROR? in mammary epithelial cells significantly enhanced cell proliferation in the ductal epithelial cells and promoted side branching of the mammary ducts. These results reveal a novel link between ROR? and E2F1 in regulating cell cycle progression and mammary tissue morphogenesis. PMID:24891616

Xiong, Gaofeng; Xu, Ren

2014-08-01

370

KMTase Set7/9 is a critical regulator of E2F1 activity upon genotoxic stress.  

PubMed

During the recent years lysine methyltransferase Set7/9 ((Su(var)-3-9, Enhancer-of-Zeste, Trithorax) domain containing protein 7/9) has emerged as an important regulator of different transcription factors. In this study, we report a novel function for Set7/9 as a critical co-activator of E2 promoter-binding factor 1 (E2F1)-dependent transcription in response to DNA damage. By means of various biochemical, cell biology, and bioinformatics approaches, we uncovered that cell-cycle progression through the G1/S checkpoint of tumour cells upon DNA damage is defined by the threshold of expression of both E2F1 and Set7/9. The latter affects the activity of E2F1 by indirectly modulating histone modifications in the promoters of E2F1-dependent genes. Moreover, Set7/9 differentially affects E2F1 transcription targets: it promotes cell proliferation via expression of the CCNE1 gene and represses apoptosis by inhibiting the TP73 gene. Our biochemical screening of the panel of lung tumour cell lines suggests that these two factors are critically important for transcriptional upregulation of the CCNE1 gene product and hence successful progression through cell cycle. These findings identify Set7/9 as a potential biomarker in tumour cells with overexpressed E2F1 activity. PMID:25124555

Lezina, L; Aksenova, V; Ivanova, T; Purmessur, N; Antonov, A V; Tentler, D; Fedorova, O; Garabadgiu, A V; Talianidis, I; Melino, G; Barlev, N A

2014-12-01

371

Cell Cycle Regulation of the Tobacco Ribonucleotide Reductase Small Subunit Gene Is Mediated by E2F-like Elements  

PubMed Central

Ribonucleotide reductase (RNR) is a key enzyme involved in the DNA synthesis pathway. The RNR-encoded genes are cell cycle regulated and specifically expressed in S phase. The promoter of the RNR2 gene encoding for the small subunit was isolated from tobacco. Both in vivo and in vitro studies of the DNA–protein interactions in synchronized BY2 tobacco cells showed that two E2F-like motifs were involved in multiple specific complexes, some of which displayed cell cycle–regulated binding activities. Moreover, these two elements could specifically interact with a purified tobacco E2F protein. Involvement of the E2F elements in regulating the RNR2 promoter was checked by functional analyses in synchronized transgenic BY2 cells transformed with various RNR2 promoter constructs fused to the luciferase reporter gene. The two E2F elements were involved in upregulation of the promoter at the G1/S transition and mutation of both elements prevented any significant induction of the RNR promoter. In addition, one of the E2F elements sharing homology with the animal E2F/cell cycle–dependent element motif behaved like a repressor when outside of the S phase. These data provide evidence that E2F elements play a crucial role in cell cycle regulation of gene transcription in plants. PMID:11041892

Chabouté, Marie-Edith; Clément, Bernadette; Sekine, Masami; Philipps, Gabriel; Chaubet-Gigot, Nicole

2000-01-01

372

Changes in E2F5 intracellular localization in mouse and human choroid plexus epithelium with development.  

PubMed

The choroid plexus epithelium (CPe) is a specialized epithelium involved primarily in the production of cerebrospoinal fluid (CSF) which is important for maintaining an optimal homeostatic environment for the brain. Although, the physiology of the CPe is fairly well understood, its development has not been thoroughly studied. It has been recently shown that mice lacking functional transcription factors, E2F5, foxJ1 or p73, develop non-obstructive hydrocephalus likely due to CPe dysfunction. We have further studied their expression in the mouse and human developing CPe, focusing particularly on E2F5. We show here that in the mouse E2F5, foxJ1 and p73 transcripts are detectable as soon as the choroid plexuses form. E2F5 protein is also detected as soon as the choroid plexuses are morphologically apparent both in mouse and human, suggesting that its expression is regulated at the transcriptional level. E2F5 protein is down-regulated late in embryogenesis and this coincides with a change in its intracellular localization, from predominantly nuclear to cytoplasmic. The pattern of expression and intracellular localization of E2F5 in vivo does not appear to correlate with that of proliferating CPe cells, as indicated by protein cell nuclear antigen (PCNA) staining, but rather with their maturation, as changes in E2F5 localization from the nucleus to the cytoplasm parallel the morphological change from pseudostratified to cuboidal epithelium. PMID:16172982

Swetloff, Adam; Ferretti, Patrizia

2005-01-01

373

Phosphorylation of HPV-16 E2 at serine 243 enables binding to Brd4 and mitotic chromosomes.  

PubMed

The papillomavirus E2 protein is involved in the maintenance of persistent infection and known to bind either to cellular factors or directly to mitotic chromosomes in order to partition the viral genome into the daughter cells. However, how the HPV-16 E2 protein acts to facilitate partitioning of the viral genome remains unclear. In this study, we found that serine 243 of HPV-16 E2, located in the hinge region, is crucial for chromosome binding during mitosis. Bromodomain protein 4 (Brd4) has been identified as a cellular binding target through which the E2 protein of bovine papillomavirus type 1 (BPV-1) tethers the viral genome to mitotic chromosomes. Mutation analysis showed that, when the residue serine 243 was substituted by glutamic acid or aspartic acid, whose negative charges mimic the effect of constitutive phosphorylation, the protein still can interact with Brd4 and colocalize with Brd4 in condensed metaphase and anaphase chromosomes. However, substitution by the polar uncharged residues asparagine or glutamine abrogated Brd4 and mitotic chromosome binding. Moreover, following treatment with the inhibitor JQ1 to release Brd4 from the chromosomes, Brd4 and E2 formed punctate foci separate from the chromosomes, further supporting the hypothesis that the association of the HPV-16 E2 protein with the chromosomes is Brd4-dependent. In addition, the S243A E2 protein has a shorter half-life than the wild type, indicating that phosphorylation of the HPV-16 E2 protein at serine 243 also increases its half-life. Thus, phosphorylation of serine 243 in the hinge region of HPV-16 E2 is essential for interaction with Brd4 and required for host chromosome binding. PMID:25340539

Chang, Szu-Wei; Liu, Wei-Chen; Liao, Kuan-Yu; Tsao, Yeou-Ping; Hsu, Pang-Hung; Chen, Show-Li

2014-01-01

374

Phosphorylation of HPV-16 E2 at Serine 243 Enables Binding to Brd4 and Mitotic Chromosomes  

PubMed Central

The papillomavirus E2 protein is involved in the maintenance of persistent infection and known to bind either to cellular factors or directly to mitotic chromosomes in order to partition the viral genome into the daughter cells. However, how the HPV-16 E2 protein acts to facilitate partitioning of the viral genome remains unclear. In this study, we found that serine 243 of HPV-16 E2, located in the hinge region, is crucial for chromosome binding during mitosis. Bromodomain protein 4 (Brd4) has been identified as a cellular binding target through which the E2 protein of bovine papillomavirus type 1 (BPV-1) tethers the viral genome to mitotic chromosomes. Mutation analysis showed that, when the residue serine 243 was substituted by glutamic acid or aspartic acid, whose negative charges mimic the effect of constitutive phosphorylation, the protein still can interact with Brd4 and colocalize with Brd4 in condensed metaphase and anaphase chromosomes. However, substitution by the polar uncharged residues asparagine or glutamine abrogated Brd4 and mitotic chromosome binding. Moreover, following treatment with the inhibitor JQ1 to release Brd4 from the chromosomes, Brd4 and E2 formed punctate foci separate from the chromosomes, further supporting the hypothesis that the association of the HPV-16 E2 protein with the chromosomes is Brd4-dependent. In addition, the S243A E2 protein has a shorter half-life than the wild type, indicating that phosphorylation of the HPV-16 E2 protein at serine 243 also increases its half-life. Thus, phosphorylation of serine 243 in the hinge region of HPV-16 E2 is essential for interaction with Brd4 and required for host chromosome binding. PMID:25340539

Chang, Szu-Wei; Liu, Wei-Chen; Liao, Kuan-Yu; Tsao, Yeou-Ping; Hsu, Pang-Hung; Chen, Show-Li

2014-01-01

375

Curcumin and Genistein, Plant Natural Products, Show Synergistic Inhibitory Effects on the Growth of Human Breast Cancer MCF7 Cells Induced by Estrogenic Pesticides  

Microsoft Academic Search

Curcumin and genistein are two natural products of plants obtained from Curcuma longa Linn (turmeric) and soybeans, respectively. Both compounds when present at micromolar concentrations are able to inhibit the growth of estrogen-positive human breast MCF-7 cells induced individually or by a mixture of the pesticides endosulfane, DDT and chlordane or 17-beta estradiol. When curcumin and genistein were added together

Surendra P. Verma; Ericka Salamone; Barry Goldin

1997-01-01

376

DNA Repair, Redox Regulation and Modulation of Estrogen Receptor Alpha Mediated Transcription  

ERIC Educational Resources Information Center

Interaction of estrogen receptor [alpha] (ER[alpha]) with 17[beta]-estradiol (E[subscript 2]) facilitates binding of the receptor to estrogen response elements (EREs) in target genes, which in turn leads to recruitment of coregulatory proteins. To better understand how estrogen-responsive genes are regulated, our laboratory identified a number of…

Curtis-Ducey, Carol Dianne

2009-01-01

377

Estradiol-Induced Object Recognition Memory Consolidation Is Dependent on Activation of mTOR Signaling in the Dorsal Hippocampus  

ERIC Educational Resources Information Center

The mammalian target of rapamycin (mTOR) signaling pathway is an important regulator of protein synthesis and is essential for various forms of hippocampal memory. Here, we asked whether the enhancement of object recognition memory consolidation produced by dorsal hippocampal infusion of 17[Beta]-estradiol (E[subscript 2]) is dependent on mTOR…

Fortress, Ashley M.; Fan, Lu; Orr, Patrick T.; Zhao, Zaorui; Frick, Karyn M.

2013-01-01

378

Multiple Methanol Transitions Detected in W51-E2 from the Arecibo Galactic Chemistry Survey  

NASA Astrophysics Data System (ADS)

Two major components of the star-forming region W51 have been observed with the Arecibo 305-m telescope as a part of the Arecibo Galactic Chemistry Survey. Located at a distance of ~6 kpc towards the Sagittarius Arm, W51 is one of the most luminous and massive (upper 5-10% by mass and upper 1% by size of all Giant Molecular Clouds in our Galaxy; Carpenter & Sanders, 1998). The infrared source, IRS1, was observed over 1.1 - 10 GHz from 2010 through 2012, and the angularly nearby compact component, E2, over 4.3 - 4.9 GHz and 8.0 - 10.2 GHz in 2014. Methanol (CH3OH) transitions at 8.34-GHz (4(1,3)-4(1,4)-+), 9.94-GHz (9(-1,9)-8(-2,7)), 9.98-GHz (4(3,2)-5(2,3)++), and 10.06-GHz (4(3,1)-5(2,4)--) were detected towards W51-E2 for the first time, some showing a mixture of emission and absorption. The peak emission ratios for the 9.94- to 9.98-GHz, and the 9.94- to 10.06-GHz transitions are consistent with the predictions of Slysh, Kalenskii & Val'tts (1993). All three 6-cm wavelength hydroxyl (OH) transitions were also detected, with the 4.66-GHz satellite line masing strongly. In IRS1, the intense methanol maser at 6.67 GHz (Araya et al. 2013) was observed to have a flux density of > 200 Jy, with the 4.66-GHz OH maser having an intensity of ~1 Jy. In IRS1, we also detected the methanol 9.94-GHz transition featuring emission with multiple components. Additionally, a total of over 60 H, 30 He, and 8 C radio recombination lines (RRLs) were identified in E2 over the two frequency ranges observed. This includes the highest frequency spectral line yet detected at Arecibo, namely the He(86)? RRL at 10.17 GHz. Over 120 H, 70 He, and 40 C recombination lines were identified in IRS1 over the frequency range of 4 - 10 GHz.

Minchin, Robert F.; Harrington, Kevin; Ghosh, Tapasi; Salter, Christopher J.; Araya, Esteban; Arce, Hector G.; Lebron Santos, Mayra E.; De Vries, Christopher H.

2015-01-01

379

A Single-Amino-Acid Polymorphism in Chikungunya Virus E2 Glycoprotein Influences Glycosaminoglycan Utilization  

PubMed Central

ABSTRACT Chikungunya virus (CHIKV) is a reemerging arbovirus responsible for outbreaks of infection throughout Asia and Africa, causing an acute illness characterized by fever, rash, and polyarthralgia. Although CHIKV infects a broad range of host cells, little is known about how CHIKV binds and gains access to the target cell interior. In this study, we tested whether glycosaminoglycan (GAG) binding is required for efficient CHIKV replication using CHIKV vaccine strain 181/25 and clinical isolate SL15649. Preincubation of strain 181/25, but not SL15649, with soluble GAGs resulted in dose-dependent inhibition of infection. While parental Chinese hamster ovary (CHO) cells are permissive for both strains, neither strain efficiently bound to or infected mutant CHO cells devoid of GAG expression. Although GAGs appear to be required for efficient binding of both strains, they exhibit differential requirements for GAGs, as SL15649 readily infected cells that express excess chondroitin sulfate but that are devoid of heparan sulfate, whereas 181/25 did not. We generated a panel of 181/25 and SL15649 variants containing reciprocal amino acid substitutions at positions 82 and 318 in the E2 glycoprotein. Reciprocal exchange at residue 82 resulted in a phenotype switch; Gly82 results in efficient infection of mutant CHO cells but a decrease in heparin binding, whereas Arg82 results in reduced infectivity of mutant cells and an increase in heparin binding. These results suggest that E2 residue 82 is a primary determinant of GAG utilization, which likely mediates attenuation of vaccine strain 181/25. IMPORTANCE Chikungunya virus (CHIKV) infection causes a debilitating rheumatic disease that can persist for months to years, and yet there are no licensed vaccines or antiviral therapies. Like other alphaviruses, CHIKV displays broad tissue tropism, which is thought to be influenced by virus-receptor interactions. In this study, we determined that cell-surface glycosaminoglycans are utilized by both a vaccine strain and a clinical isolate of CHIKV to mediate virus binding. We also identified an amino acid polymorphism in the viral E2 attachment protein that influences utilization of glycosaminoglycans. These data enhance an understanding of the viral and host determinants of CHIKV cell entry, which may foster development of new antivirals that act by blocking this key step in viral infection. PMID:24371059

Silva, Laurie A.; Khomandiak, Solomiia; Ashbrook, Alison W.; Weller, Romy; Heise, Mark T.; Morrison, Thomas E.

2014-01-01

380

Expression of the HPV18E2 gene in cervical cancer and premalignant lesions and its clinical significance.  

PubMed

This study aims to observe the expression of the HPV18E2 gene in cervical cancer and premalignant lesions and to investigate its clinical significance. The expression of the HPV18E2 gene in the cervical tissues obtained from 38 women with cervical lesions was detected using the RT-PCR method. The pathological changes were graded based on cervical intraepithelial neoplasia (CIN) criteria. The HPV18E2 gene was expressed mainly in cervical premalignant lesions, 60 % in Grade I CIN, 33.3 % in Grade II CIN, and 28.6 % in Grade III CIN. No expression was detected in cervical cancer and chronic cervical inflammation. This study suggests that peptides vaccine targeting the HPV18E2 protein may disrupt and prohibit the progress of diseases induced by HPV 18 infection (i.e., CIN and cervical cancer). PMID:24777814

Mou, Ling; Wu, Bin; Hu, Ya; Lan, Ying; Lv, Feng-Lin

2014-11-01

381

A role of NF-E2 in chronic inflammation and clonal evolution in essential thrombocythemia, polycythemia vera and myelofibrosis?  

PubMed

A novel murine model for myeloproliferative neoplasms (MPNs) generated by overexpression of the transcription factor NF-E2 has recently been described. Sustained overexpression of NF-E2 in this model induced myeloid expansion with anemia, leukocytosis and thrombocytosis. Herein, it is debated if NF-E2 overexpression also might have induced a sustained state of in vivo leukocyte and platelet activation with chronic and self-perpetuating production of inflammatory products from activated leukocytes and platelets. If so, this novel murine model also may excellently describe the deleterious impact of sustained chronic NF-E2 overexpression during uncontrolled chronic inflammation upon the hematopoietic system--the development of clonal myeloproliferation. Accordingly, this novel murine model may also have delivered the proof of concept of chronic inflammation as a trigger and driver of clonal evolution in MPNs. PMID:23932394

Hasselbalch, Hans C

2014-02-01

382

78 FR 42530 - Prospective Grant of an Exclusive License: Human Papillomavirus 16 E2 and E6 Peptides for...  

Federal Register 2010, 2011, 2012, 2013

...invention pertains primarily to CD8+ T cell epitopes from HPV16 E2. These epitopes generated from amino acid positions 69-77...protein that comprise class I restricted T cell epitopes and methods of administering the same. The...

2013-07-16

383

40 CFR Table E-2 to Subpart E of... - Spectral Energy Distribution and Permitted Tolerance for Conducting Radiative Tests  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Spectral Energy Distribution and Permitted Tolerance for Conducting Radiative Tests E Table E-2 to Subpart E of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

2010-07-01

384

The roles of Rb, p107, and E2f4 in bone formation and embryonic development  

E-print Network

The pocket proteins, through their interaction with the E2F transcription factors, ensure the proper regulati