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1

Cloning, expression, and induction by 17-beta estradiol (E2) of a vitellogenin gene in the white cloud mountain minnow Tanichthys albonubes.  

PubMed

Vitellogenins (Vtgs), the precursors for the yolk proteins, are very important for the embryonic development of teleosts, and have also been studied extensively as biomarkers for environmental estrogenic mimics. The cDNA for a Vtg was isolated from the liver of the female white cloud mountain minnow (Tanichthys albonubes) by 3'- and 5'-RACE methods. It is 4,171 bp in full length, and encodes a putative protein of 1,326 amino acids. This putative Vtg, designated as wcmmVtg, contains complete portions of LVI and PV, but lacks the C-terminal half of LVII and thus belongs to type I vitellogenin. In addition to the liver of the female fish, wcmmVtg was also shown to be expressed in the ovary. During ovarian development, the mRNA expression of wcmmVtg in both the liver and ovary was continuously increased from the previtellogenic to late vitellogenic stages, but then decreased significantly at post-spawning stage. In the male fish, expression of wcmmVtg mRNA was induced in the liver by treatment with E2 (10 and 100 ng/l) for 14 days. These results suggest that the Vtg originated from the ovary of the white cloud mountain minnow may also contribute to the accumulation of yolk proteins during oocyte growth, and that the male white cloud mountain minnow is sensitive to the estrogenic treatment in terms of Vtg mRNA expression, which could also be applied to monitor the environmental estrogenic mimics. PMID:20467857

Wang, Ruilong; Gao, Yun; Zhang, Lihong; Zhang, Yike; Fang, Zhanqiang; He, Jianguo; Zhang, Weimin; Ma, Guangzhi

2010-06-01

2

IN SITU SUBSURFACE SOIL STUDIES ON THE OCCURRENCE, PERSISTENCE, AND PATHWAYS OF 17BETA-ESTRADIOL.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hormones, such as 17beta-estradiol (E2), have the potential of causing widespread physiological and reproductive disorders in numerous species due to their potency and presence in the environment. The occurrence of E2 in the unsaturated zone (0.60 m depth) was determined with wick lysimeters and com...

3

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...

4

Low-dosage micronized 17 beta-estradiol prevents bone loss in postmenopausal women  

NASA Technical Reports Server (NTRS)

With the use of a double-blind, randomized, dose-ranging design, we tested during an 18-month period the degree of protection against postmenopausal bone loss afforded by micronized 17 beta-estradiol in dosages of 0.5, 1.0, and 2.0 mg. All subjects received supplementation to ensure a minimum of 1500 mg calcium daily. Fifty-one subjects completed at least 1 year of follow-up bone density measurements by quantitative computed tomography and by single- and dual-photon absorptiometry. In the placebo group spinal trabecular bone density decreased 4.9% annually (p less than 0.001), whereas in those taking micronized 17 beta-estradiol bone density tended to increase (annual increases of 0.3% in the 0.5 mg micronized 17 beta-estradiol group, 1.8% in the 1.0 mg micronized 17 beta-estradiol group, and 2.5% in the 2.0 mg micronized 17 beta-estradiol group). After completing the double-blind phase, 41 subjects completed an additional 18 months of follow-up while taking 1.0 mg micronized 17 beta-estradiol. During this time one third of the subjects were randomly assigned to discontinue calcium supplements. Among those who previously received placebo, trabecular bone density increased 4.3% annually, whereas among those who had used micronized 17 beta-estradiol, trabecular bone density response was inversely related to the dosage previously used. Additionally and independently, the level of calcium intake showed a statistically significant correlation with the change in spinal trabecular bone density (r = 0.37, p = 0.02). We conclude that micronized 17 beta-estradiol has a continuous skeletal dose-response effect in the range of 0.5 to 2.0 mg and that calcium intake positively modifies the skeletal response to 1.0 mg micronized 17 beta-estradiol.

Ettinger, B.; Genant, H. K.; Steiger, P.; Madvig, P.

1992-01-01

5

17beta-Estradiol releases thyroxine from the thyroid follicles of a teleost, Channa gachua (Ham. )  

SciTech Connect

To observe a direct effect of 17beta-estradiol (E2) on thyroid activity, thyroid follicles were isolated from hypobranchial muscles of a freshwater murrel, Channa gachua. Thyroid follicles were incubated (5 X 10{sup 6} follicles/well) in vitro at 30{degree}C for 2 hr without hormone and then 3 hr with E2 or bovine thyroid-stimulating hormone (bTSH). Addition of 10 and 100 ng of E2 to thyroid follicles resulted in 2- and 3-fold increases in thyroxine (T4) release. When 100 ng of bTSH was added to check the isolated follicular function, it stimulated T4 release to more than 3-fold. Increasing doses of E2 from 1 to 100 ng caused a dose-dependent stimulation of T4 release, while a 1000-ng dose reduced T4 release compared to 100 ng. When thyroid follicles of this experiment were lysed by sonication and T4 content was determined, it corroborated the profile of T4 release in response to varied E2 doses. E2 was ineffective in increasing {sup 125}I uptake by the follicles, while bTSH elevated it by 45% over the control. Incubation of varied concentrations of ({sup 3}H)estradiol with cytosol and nuclear fractions of thyroid follicles in the presence of a 100-fold excess of diethylstilbestrol showed saturable specific binding of E2.

Bandyopadhyay, S.; Banerjee, P.P.; Bhattacharya, S. (Visva-Bharati Univ., West Bengal, (India))

1991-02-01

6

17beta-estradiol protects male mice from cuprizone-induced demyelination and oligodendrocyte loss.  

PubMed

In addition to regulating reproductive functions in the brain and periphery, estrogen has tropic and neuroprotective functions in the central nervous system (CNS). Estrogen administration has been demonstrated to provide protection in several animal models of CNS disorders, including stroke, brain injury, epilepsy, Parkinson's disease, Alzheimer's disease, age-related cognitive decline and multiple sclerosis. Here, we use a model of toxin-induced oligodendrocyte death which results in demyelination, reactive gliosis, recruitment of oligodendrocyte precursor cells and subsequent remyelination to study the potential benefit of 17beta-estradiol (E2) administration in male mice. The results indicate that E2 partially ameliorates loss of oligodendrocytes and demyelination in the corpus callosum. This protection is accompanied by a delay in microglia accumulation as well as reduced mRNA expression of the pro-inflammatory cytokine, tumor necrosis factor alpha (TNFalpha), and insulin-like growth factor-1 (IGF-1). E2 did not significantly alter the accumulation of astrocytes or oligodendrocyte precursor cells, or remyelination. These data obtained from a toxin-induced, T cell-independent model using male mice provide an expanded view of the beneficial effects of estrogen on oligodendrocyte and myelin preservation. PMID:20347981

Taylor, Lorelei C; Puranam, Kasturi; Gilmore, Wendy; Ting, Jenny P-Y; Matsushima, Glenn K

2010-08-01

7

Development of a vaginal ring for achieving physiologic levels of 17 beta-estradiol in hypoestrogenic women.  

PubMed

The ability of polysiloxane vaginal rings containing 17 beta-Estradiol (E2) to deliver E2 into the systemic circulation at a steady rate over long periods of time was evaluated in castrate and postmenopausal volunteers. Standard laminar designs, used to release contraceptive gestagens, deliver low levels of E2 (about 50 pg/ml) and only for 1 month. With a modified design, E2 levels of 109 to 159 pg/ml were maintained for at least 3 months, and circulating gonadotropins were suppressed to values approaching the premenopausal range. This homogeneous design provides for physiologic replacement of E2 as well as a practical research tool for studying chronic effects of E2 in human subjects. PMID:6798058

Stumpf, P G; Maruca, J; Santen, R J; Demers, L M

1982-01-01

8

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...

9

17beta-estradiol mediated protection against vascular leak after hemorrhagic shock: role of estrogen receptors and apoptotic signaling.  

PubMed

Vascular hyperpermeability is a clinical complication associated with hemorrhagic shock (HS) and occurs mainly because of the disruption of the adherens junctional complex. The objective of this study was to understand the role of 17beta-estradiol in HS-induced hyperpermeability particularly focusing on estrogen receptors. In male Sprague-Dawley rats, HS was induced by withdrawing blood to reduce the mean arterial pressure to 40 mmHg for 1 hour followed by 1 hour of resuscitation to 90 mmHg. The study groups were 17beta-estradiol, tamoxifen, fulvestrant plus 17beta-estradiol, propyl pyrazole triol plus 17beta-estradiol, and diarylpropionitrile plus 17beta-estradiol. Intravital microscopy was used to study changes in mesenteric postcapillary venules. Mitochondrial reactive oxygen species formation was studied in vivo using dihydrorhodamine 123. The mitochondrial transmembrane potential was studied using the fluorescent cationic probe 5,5',6,6'tetrachloro-1,1',3,3'tetraethylbenzimidazolyl carbocyanine iodide (JC-1). The mesenteric microvasculature was analyzed for cytochrome c levels by enzyme-linked immunosorbent assay and caspase-3 activity by a fluorometric assay. Our results demonstrated that 17beta-estradiol attenuated HS-induced hyperpermeability. Fulvestrant reversed this protective effect (P < 0.05). Tamoxifen 5 mg/kg attenuated HS-induced hyperpermeability, whereas 10 mg/kg induced permeability (P < 0.05). Both alpha and beta estrogen receptor agonists inhibited HS-induced hyperpermeability (P < 0.05). 17beta-Estradiol decreased HS-induced reactive oxygen species formation and restored mitochondrial transmembrane potential. 17beta-Estradiol decreased both cytosolic cytochrome c level and activation of caspase-3 (P < 0.05). These findings suggest that 17beta-estradiol protects the microvasculature after HS, and that this protection may be mediated through the alpha and beta estrogen receptors. PMID:20160663

Childs, Ed W; Tharakan, Binu; Hunter, Felicia A; Smythe, W Roy

2010-09-01

10

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

11

Effect of endogenous androgens on 17beta-estradiol-mediated protection after spinal cord injury in male rats.  

PubMed

Several groups have recently shown that 17beta-estradiol is protective in spinal cord injury (SCI). Testosterone can be aromatized to 17beta-estradiol and may increase estrogen-mediated protection. Alternatively, testosterone has been shown to increase excitotoxicity in models of central nervous system (CNS) injury. These experiments test the hypothesis that endogenous testosterone in male rats alters 17beta-estradiol-mediated protection by evaluating a delayed administration over a clinically relevant dose range and manipulating testicular-derived testosterone. Adult male Sprague Dawley rats were either gonadectomized or left gonad-intact prior to SCI. SCI was produced by a midthoracic crush injury. At 30 min post SCI, animals received a subcutaneous pellet of 0.0, 0.05, 0.5, or 5.0 mg of 17beta-estradiol, released over 21 days. Hindlimb locomotion was analyzed weekly in the open field. Spinal cords were collected and analyzed for cell death, expression of Bcl-family proteins, and white-matter sparing. Post-SCI administration of the 0.5- or 5.0-mg pellet improved hindlimb locomotion, reduced urinary bladder size, increased neuronal survival, reduced apoptosis, improved the Bax/Bcl-xL protein ratio, and increased white-matter sparing. In the absence of endogenous testicular-derived androgens, SCI induced greater apoptosis, yet 17beta-estradiol administration reduced apoptosis to the same extent in gonadectomized and gonad-intact male rats. These data suggest that delayed post-SCI administration of a clinically relevant dose of 17beta-estradiol is protective in male rats, and endogenous androgens do not alter estrogen-mediated protection. These data suggest that 17beta-estradiol is an effective therapeutic intervention for reducing secondary damage after SCI in males, which could be readily translated to clinical trials. PMID:20001688

Kachadroka, Supatra; Hall, Alicia M; Niedzielko, Tracy L; Chongthammakun, Sukumal; Floyd, Candace L

2010-03-01

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

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

14

Progesterone and 17 beta-estradiol acutely stimulate nitric oxide synthase activity in rat aorta and inhibit platelet aggregation.  

PubMed

The rapid non-genomic stimulatory action of progesterone (Pg) and estradiol (E2) on nitric oxide synthase (NOS) activity of endothelium intact aortic rings and its effect on platelet aggregation was investigated. First we measured the effect of the hormones on platelet aggregation when added to rat aortic strips (RAS) incubated in a PRP. RAS induced an antiaggregatory activity, which was enhanced by the presence of the hormones. The inhibitory action induced by the hormones was evoked in a dose dependent manner (10 pM-100 nM). These effects are specific for progesterone and 17-beta-estradiol, since either testosterone and 17-alpha-estradiol were devoid of activity. The hormones induced rapid responses, producing significant inhibition within 1 to 5 minutes of hormonal exposure. The addition of 10(-5) M L-NAME suppressed the antiaggregatory effect of 1 nM E2 or 10 nM Pg. Furthermore, we specifically quantified the NO generation by the 3H-citrulline technique. 10(-8) M E2 induced 2-fold increase of RAS citrulline production, while the increment induced by 10(-7) M Pg was 55% over control. Preincubation with 10(-5) M L-NAME completely suppressed the stimulatory action of 10(-9) M E2 or 10(-8) M Pg, confirming that the antiaggregatory factor released from the aortic tissue was NO. Preincubation with cycloheximide did not block the increment in NO induced by the hormones. In conclusion the present study provides for the first time evidence of acute, non-genomic effects of Pg on rat aorta NOS activity and platelet aggregation in coincidence with the results obtained with estradiol treatment. PMID:11487093

Selles, J; Polini, N; Alvarez, C; Massheimer, V

2001-07-01

15

Feminization of female leukophore-free strain of Japanese medaka (Oryzias latipes) exposed to 17beta-estradiol.  

PubMed

The recently developed female leukophore-free (FLFII) strain of Japanese medaka (Oryzias latipes) carries DNA markers for the identification of genotypic sex. Information regarding genotypic sex is useful for tests in which endocrine-disrupting compounds may masculinize or feminize fish. In the present study, methods were developed to automate DNA extraction and profiling for rapid determination of genotypic sex. Adequate amounts of DNA were isolated by robotic extraction procedures from the caudal fin. New primers were developed to include an 18-base pair segment that is in the X chromosome of female medaka but is absent in the Y chromosome of male medaka. Automated profiling methods with 96-well plates permitted analysis of the genomic sex of medaka at rates of up to 500 fish/d. We investigated the sensitivity of the FLFII strain to the feminizing effects of the potent estrogen 17beta-estradiol (E2), and we compared this sensitivity to that of a wild strain that has been used widely in the study of endocrine-disrupting compounds. All FLFII medaka exposed to 1 microg/L of E2 (n = 50) had the female gonadal phenotype (i.e., ovaries), and all but one wild-strain medaka exposed to 1 microg/L of E2 (i.e., 47 of 48 fish) had the female gonadal phenotype, indicating that the FLFII and wild strains have approximately equal sensitivities to the feminizing effects of E2. Analysis of the genotype of FLFII medaka confirmed that 100% of fish with the male genotype had been feminized to the female gonadal phenotype. The FLFII strain is an excellent teleost model for detecting feminization or masculinization of fish, and automated methods can be used for rapid analysis of the genotypic sex of FLFII medaka. PMID:15559293

Balch, Gordon C; Shami, Karmi; Wilson, Paul J; Wakamatsu, Yuko; Metcalfe, Chris D

2004-11-01

16

Mammary tumor induction in ACI rats exposed to low levels of 17beta-estradiol.  

PubMed

Animal models play a major role in understanding the etiology, molecular mechanisms, strategizing intervention and treatment of human diseases. ACI, an inbred line derived from August and Copenhagen strains, is unique for its susceptibility to estrogen-induced mammary tumors. Histologically and in many molecular aspects, the tumors formed in these rats are similar to human breast cancers. Previous studies have shown high mortality and significant weight loss in this model associated with pituitary gland abnormality. We hypothesized that this could be due to overwhelming the biological system with estrogen. Three groups of female ACI rats (7-8 weeks) received either 3-cm sham silastic implants, or the conventional 3-cm silastic implants containing 27 mg of 17beta-estradiol, or 1.2-cm silastic implants containing 9 mg 17beta-estradiol. The sham and 3-cm implant rats were euthanized at 180 days while the 1.2-cm implant rats were euthanized at 240 days. The 1.2-cm implants resulted in significantly reduced serum estrogen levels and pituitary gland size. Animals with 1.2-cm implants had 100% tumor incidence, while not all rats developed tumors with 3-cm implants. Both the tumor burden (from 1,011+/-402 to 2,324+/-454 mm(3); p=0.01) and tumor multiplicity (from 5.78+/-1.4 to 7.6+/-1.04) increased by lowering the estrogen dose, and the inter-animal variability in the tumor indices decreased. Finally, the weight of the pituitary gland was also significantly (p=0.0004) reduced (from 178+/-23.5 mg to 80+/-8.9 mg) and the mortality rate decreased from 42% to 0% (p=0.01). Our data indicate that the improvised model will provide valuable insights into the molecular alterations in the estrogen-induced mammary tumorigenesis and will be ideal for inhibition studies. PMID:17549411

Ravoori, Srivani; Vadhanam, Manicka V; Sahoo, Sunati; Srinivasan, Cidambi; Gupta, Ramesh C

2007-07-01

17

Comparative 17beta-estradiol response and lipoprotein interactions of an avian apolipoprotein.  

PubMed

Apolipoprotein D (apo D), a member of the lipocalin protein family, has been identified and cloned in several mammalian species; its physiological functions, however, remain poorly understood. As with other lipocalins, apo D can bind small hydrophobic ligands. Lipids and hormones, such as cholesterol, arachidonic acid, and progesterone can bind to apo D; but the physiological significance of these interactions is not clear. We previously reported the existence of an avian (Gallus domesticus) apo D-like protein, and indicated a possible role for it in reproduction. This report provides a further comparative characterization of this avian protein. Evidence is presented that the putative avian apo D, like some (e.g., human) but not other (e.g., rat) mammalian apo Ds, preferentially associates with high density lipoproteins (HDL) in the circulation. These results confirm the apolipoprotein nature of the avian apo D-like protein, and indicate that it has conserved the HDL-interaction property of some mammalian apo Ds. The response of circulatory levels of the avian protein to 17beta-estradiol treatment is also examined. Large estrogen-dependent increases are known to occur in the circulatory levels of some avian apolipoproteins, such as apo B and vitellogenins, that represent major yolk precursors and nutrient sources for the embryo. Although the avian apo D-like protein is also a known yolk precursor, the minor estrogen-dependent increase observed for this apolipoprotein (less than 7% that of apo B) distinguishes it from the major yolk-precursor apolipoproteins. The response of the avian apo D-like protein to 17beta-estradiol is more like that of other yolk precursor proteins that transport regulatory molecules such as vitamin A and thyroid hormones. PMID:12161206

Yao, Yu; Vieira, Amandio

2002-06-01

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

17beta-estradiol potently suppresses cAMP-induced insulin-like growth factor-I gene activation in primary rat osteoblast cultures  

NASA Technical Reports Server (NTRS)

Insulin-like growth factor-I (IGF-I) is a key factor in bone remodeling. In osteoblasts, IGF-I synthesis is enhanced by parathyroid hormone and prostaglandin E2 (PGE2) through cAMP-activated protein kinase. In rats, estrogen loss after ovariectomy leads to a rise in serum IGF-I and an increase in bone remodeling, both of which are reversed by estrogen treatment. To examine estrogen-dependent regulation of IGF-I expression at the molecular level, primary fetal rat osteoblasts were co-transfected with the estrogen receptor (hER, to ensure active ER expression), and luciferase reporter plasmids controlled by promoter 1 of the rat IGF-I gene (IGF-I P1), used exclusively in these cells. As reported, 1 microM PGE2 increased IGF-I P1 activity by 5-fold. 17beta-Estradiol alone had no effect, but dose-dependently suppressed the stimulatory effect of PGE2 by up to 90% (ED50 approximately 0.1 nM). This occurred within 3 h, persisted for at least 16 h, required ER, and appeared specific, since 17alpha-estradiol was 100-300-fold less effective. By contrast, 17beta-estradiol stimulated estrogen response element (ERE)-dependent reporter expression by up to 10-fold. 17beta-Estradiol also suppressed an IGF-I P1 construct retaining only minimal promoter sequence required for cAMP-dependent gene activation, but did not affect the 60-fold increase in cAMP induced by PGE2. There is no consensus ERE in rat IGF-I P1, suggesting novel downstream interactions in the cAMP pathway that normally enhances IGF-I expression in skeletal cells. To explore this, nuclear extract from osteoblasts expressing hER were examined by electrophoretic mobility shift assay using the atypical cAMP response element in IGF-I P1. Estrogen alone did not cause DNA-protein binding, while PGE2 induced a characteristic gel shift complex. Co-treatment with both hormones caused a gel shift greatly diminished in intensity, consistent with their combined effects on IGF-I promoter activity. Nonetheless, hER did not bind IGF-I cAMP response element or any adjacent sequences. These results provide new molecular evidence that estrogen may temper the biological effects of hormones acting through cAMP to regulate skeletal IGF-I expression and activity.

McCarthy, T. L.; Ji, C.; Shu, H.; Casinghino, S.; Crothers, K.; Rotwein, P.; Centrella, M.

1997-01-01

20

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

21

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

22

Degradation of 17beta-estradiol in aqueous solution by ozonation in the presence of manganese(II) and oxalic acid.  

PubMed

Natural estrogens, such as 17beta-estradiol (E2), are the main substances responsible for estrogenic activity found in domestic sewage. In the work described herein, the degradation of E2 has been investigated by single ozonation and catalytic ozonation in the presence of manganese ion (Mn2+) and oxalic acid. The presence of Mn2+ and oxalic acid in the ozonation processes significantly improved the E2 degradation and, hence, the reduction of estrogenic activity in aqueous solution. The addition of Mn2+ and oxalic acid produced many more hydroxyl radicals in the catalytic ozonation system than in the single ozonation system. Oxidation products formed during ozonation of E2 have been identified by means of gas chromatography-mass spectrometry (GC-MS), on the basis of which a possible reaction pathway for E2 degradation by ozonation is proposed. E2 was first oxidized to hydroxyl-semiquinone isomers, and these were subsequently degraded to low molecular weight compounds such as oxalic acid and malonic acid. The latter were easily oxidized by ozone to form carbon dioxide (CO2). The results demonstrate that the ozonation-Mn(2+)-oxalic acid system may serve as a powerful tool for removing E2, and the addition of Mn2+ and oxalic acid is favourable for the complete removal of estrogenic activity induced by steroid estrogens in aqueous solution. PMID:23530323

Jiang, Liying; Zhang, Lu; Chen, Jianmeng; Ji, Hong

2013-01-01

23

Arctic char (Salvelinus alpinus) metallothionein: cDNA sequence, expression, and tissue-specific inhibition of cadmium-mediated metallothionein induction by 17{beta}-estradiol, 4-OH-PCB 30, and PCB 104  

SciTech Connect

In this study, the authors have examined the basal level expression and tissue-specific expression patterns of metallothionein (MT) in Arctic char following metal and E2 (17{beta}-estradiol) treatment. To study the gene regulation in Arctic char, the two MT isoforms were isolated from a lambda-ZAP hepatic cDNA library and characterized. Determination of basal MT and mRNA and MT expression for 10 different tissues revealed a lack of correlation between MT and mRNA and MT levels. The inducibility of MT mRNA and the correlation to resulting MT levels were then determined for liver and kidney. They found a more rapid and stronger induction of MT mRNA in liver than in kidney at day 1 and 3 postinjection, whereas the MT protein quantification showed higher MT levels in kidney than in liver at days 3 and 7 postinjection. These discrepancies indicate that differences in metal handling or posttranscriptional regulation of MT exists between tissues. Whereas metals induce MT synthesis, E2 inhibit the hepatic MT expression. To examine the tissue specificity of this inhibition, the authors determined the effect of 17{beta}-estradiol (E2) and two estrogenic PCBs (4{prime}-OH-PCB 30 and PCB 104) on Cd-mediated MT induction in liver and kidney. Although E2 and the estrogenic PCBs inhibited cadmium-mediated hepatic MT induction, these compounds did not interfere with renal MT induction.

Gerpe, M.; Kling, P.; Berg, A.H.; Olsson, P.E.

2000-03-01

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

Potentiating effect of growth hormone on vitellogenin synthesis induced by 17 beta-estradiol in primary culture of female silver eel (Anguilla anguilla L.) hepatocytes.  

PubMed

Previous in vivo experiments have indicated a potentiating role of growth hormone (GH) during experimentally induced vitellogenesis by 17-beta-estradiol (E2) in the female silver eel (Anguilla anguilla L.). To investigate whether GH has direct hepatic actions, the effects of hypophysial-purified and recombinant QH on vitellogenin (Vg) synthesis in response to E2 were tested on primary cultures of hepatocytes. Hepatocytes were prepared from control or E2-primed eels. Addition of E2 alone into the culture medium induced both Vg synthesis and secretion in a dose- and time-related fashion. Bovine growth hormone (bGH) alone had no effect on the induction of Vg synthesis or secretion. Bovine GH enhanced the in vitro effects of F2 on both Vg synthesis and secretion, an effect attenuated by an in vivo E2 priming which was dose-dependent with an ED(50) of 5 ng/ml. To investigate the specificity of GH action, purified eel and salmon GH and salmon, trout, and tilapia prolactins (PRL), as well as recombinant trout and tilapia GH, were tested, and the responses were compared to bGH. Purified salmon and homologous eel GH potentiated the vitellogenic response to F2. Recombinant GH were highly efficacious, excluding the presence of active contaminants in the potentiating effect of GH preparations. The potentiating effect of recombinant trout GH on the vitellogenic response was reduced at high doses (above 20 ng/ml), suggesting a down-regulation of GH binding sites by GH itself. Salmon PRL has minimal activity, but not trout and tilapia PRL, indicating that PRL is not an important potentiating factor on Vg synthesis in our model. It is concluded that GH acts directly on the liver to potentiate E2 induction of eel hepatic Vg synthesis. The potentiating effect of GH appears to be time- and dose-dependent and modulated as a function of hormonal status (E2 priming) of the eel. PMID:8998971

Peyon, P; Baloche, S; Burzawa-Gerard, E

1996-05-01

26

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

27

Transport of 17beta-estradiol and testosterone in a field lysimeter  

Technology Transfer Automated Retrieval System (TEKTRAN)

17ß-estradiol (E2) and testosterone (T) are present in sources such as waste treatment effluent and manures, and can potentially disrupt aquatic organisms at low concentrations. Laboratory studies consistently indicate limited mobility and rapid attenuation of E2 and T in soils; however, these hormo...

28

Effects of daidzein, genistein, and 17beta-estradiol on 7,12-dimethylbenz[a]anthracene-induced mutagenicity and uterine dysplasia in ovariectomized rats.  

PubMed

Phytoestrogens, primarily isoflavones daidzein (DZ) and genistein (GE), are increasingly used by postmenopausal women as an alternative to hormone replacement therapy due to reports that estrogen therapy increases the risk of breast and endometrial cancers. These compounds, as estrogen receptor agonists, may influence chemical carcinogenesis in estrogen-responsive tissues such as the uterus. We utilized ovariectomized (OVX) rats to model menopause and assessed the effects of dietary DZ, GE, or 17beta-estradiol (E2) on carcinogen-induced mutagenesis and carcinogenesis in the rat uterus. Big Blue transgenic rats (derived from Fischer 344 strain) were exposed to 7,12-dimethylbenz[a]anthracene (DMBA) in the presence or absence of the supplements. At 16- or 20-wk sacrifice, the uteri were removed and processed to determine mutant frequencies (MFs) and immunohistochemical or histopathological parameters, respectively. In rats treated with DMBA alone, a significant increase in lacI MFs (P < 0.01) in both OVX and intact (INT) rats was observed. The DMBA-induced MFs were not significantly altered by dietary DZ, GE, or E2 in both OVX and INT rats. Although dysplasia was not induced in the uterus of OVX and INT rats treated with DMBA alone, it was detected in 55% of OVX rats fed E2 alone and in 100% of OVX rats fed E2 along with DMBA exposure. Cell proliferation also was significantly higher in OVX rats fed E2 and treated with DMBA. In rats fed the isoflavones and treated with DMBA, the incidence of dysplasia was either reduced or virtually absent in both OVX and INT groups. These results indicate that a high incidence of dysplasia was associated with E2 feeding with or without DMBA treatment in the OVX rats, whereas the incidence was low in rats fed DZ or GE and treated with DMBA, suggesting a weak estrogen receptor agonist of DZ or GE in the rat uterus. The absence of dysplasia in OVX rats exposed to DMBA alone also suggests, in part, a promotional mechanism via estrogen- or isoflavone-driven cell proliferation. PMID:16351510

Aidoo, Anane; Bishop, Michelle E; Shelton, Sharon D; Lyn-Cook, Lascelles E; Chen, Tao; Manjanatha, Mugimane G

2005-01-01

29

Stimulation of catecholamine synthesis through unique estrogen receptors in the bovine adrenomedullary plasma membrane by 17{beta}-estradiol  

SciTech Connect

Incubation of cultured bovine adrenal medullary cells with 17{beta}-estradiol (E{sub 2}) (0.3-100 nM) or membrane-impermeable E{sub 2}-bovine serum albumin (100 nM) acutely increased {sup 14}C-catecholamine synthesis from [{sup 14}C]tyrosine. The stimulatory effect of E{sub 2} was not inhibited by ICI182,780, a nuclear estrogen receptor inhibitor. E{sub 2} also increased tyrosine hydroxylase activity and p44/42MAPK phosphorylation, the former of which was attenuated by U0126, an inhibitor of p44/42MAPK kinase. The plasma membrane isolated from the gland showed two classes of specific binding sites of [{sup 3}H]E{sub 2} with apparent K {sub d}s of 3.2 and 106 nM, and B {sub max}s of 0.44 and 8.5 pmol/mg protein, respectively. The high-affinity binding of [{sup 3}H]E{sub 2} was most strongly inhibited by E{sub 2} and phytoestrogens, and to lesser extents by other steroid hormones, while it was enhanced by ICI182,780 and environmental estrogenic pollutants. These findings suggest that E{sub 2} acutely stimulates catecholamine synthesis via activation of p44/42MAPK through unique estrogen receptors in the plasma membrane of bovine adrenal medulla.

Yanagihara, Nobuyuki [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan)]. E-mail: yanagin@med.uoeh-u.ac.jp; Liu, Minhui [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan); Toyohira, Yumiko [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan); Tsutsui, Masato [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan); Ueno, Susumu [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan); Shinohara, Yuko [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan); Takahashi, Kojiro [Department of Hospital Pharmacy, University Hospital, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan); Tanaka, Kazumi [Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan)

2006-01-13

30

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

31

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

32

Up-regulation of PI3K/Akt signaling by 17{beta}-estradiol through activation of estrogen receptor-{alpha}, but not estrogen receptor-{beta}, and stimulates cell growth in breast cancer cells  

SciTech Connect

Estrogen stimulates cell proliferation in breast cancer. The biological effects of estrogen are mediated through two intracellular receptors, estrogen receptor-{alpha} (ER{alpha}) and estrogen receptor-{beta} (ER{beta}). However, the role of ERs in the proliferative action of estrogen is not well established. Recently, it has been known that ER activates phosphatidylinositol-3-OH kinase (PI3K) through binding with the p85 regulatory subunit of PI3K. Therefore, possible mechanisms may include ER-mediated phosphoinositide metabolism with subsequent formation of phosphatidylinositol-3,4,5-trisphosphate (PIP{sub 3}), which is generated from phosphatidylinositol 4,5-bisphosphate via PI3K activation. The present study demonstrates that 17{beta}-estradiol (E2) up-regulates PI3K in an ER{alpha}-dependent manner, but not ER{beta}, and stimulates cell growth in breast cancer cells. In order to study this phenomenon, we have treated ER{alpha}-positive MCF-7 cells and ER{alpha}-negative MDA-MB-231 cells with 10 nM E2. Treatment of MCF-7 cells with E2 resulted in a marked increase in PI3K (p85) expression, which paralleled an increase in phospho-Akt (Ser-473) and PIP{sub 3} level. These observations also correlated with an increased activity to E2-induced cell proliferation. However, these effects of E2 on breast cancer cells were not observed in the MDA-MB-231 cell line, indicating that the E2-mediated up-regulation of PI3K/Akt pathway is ER{alpha}-dependent. These results suggest that estrogen activates PI3K/Akt signaling through ER{alpha}-dependent mechanism in MCF-7 cells.

Lee, Young-Rae [Department of Biochemistry, Center for Healthcare Technology Development, Chonbuk National University Medical School, Jeonju 560-756 (Korea, Republic of); Park, Jinny [Division of Hematology/Oncology, Department of Medicine, Cheju National University College of Medicine, Jeju 670-716 (Korea, Republic of); Yu, Hong-Nu [Department of Biochemistry, Center for Healthcare Technology Development, Chonbuk National University Medical School, Jeonju 560-756 (Korea, Republic of); Kim, Jong-Suk [Department of Biochemistry, Center for Healthcare Technology Development, Chonbuk National University Medical School, Jeonju 560-756 (Korea, Republic of); Youn, Hyun Jo [Department of Surgery, Chonbuk National University Medical School, Jeonju 560-756 (Korea, Republic of); Jung, Sung Hoo [Department of Surgery, Chonbuk National University Medical School, Jeonju 560-756 (Korea, Republic of)]. E-mail: shjung@chonbuk.ac.kr

2005-11-04

33

Low 17beta-estradiol levels in CNR1 knock-out mice affect spermatid chromatin remodeling by interfering with chromatin reorganization.  

PubMed

The type 1-cannabinoid receptor, CNR1, regulates differentiation of spermatids. Indeed, we have recently reported that the genetic inactivation of Cnr1 in mice influenced chromatin remodeling of spermatids, by reducing histone displacement and then sperm chromatin quality indices (chromatin condensation and DNA integrity). Herein, we have studied, at both central and testicular levels, the molecular signals potentially involved in histone displacement. In particular, investigation of the neuroendocrine axis involved in estrogen production demonstrated down-regulation of the axis supporting FSH/estrogen secretion in Cnr1-knockout male mice. Conversely, Cnr1-knockout male mice treated with 17beta-estradiol showed a weak increase of pituitary Fsh-beta subunit mRNA levels and a rescue of sperm chromatin quality indices demonstrating that estrogens, possibly in combination with FSH secretion, play an important role in regulating chromatin remodeling of spermatids. PMID:23677985

Cacciola, Giovanna; Chioccarelli, Teresa; Altucci, Lucia; Ledent, Catherine; Mason, J Ian; Fasano, Silvia; Pierantoni, Riccardo; Cobellis, Gilda

2013-06-01

34

Apparent absence of negative feedback in middle-aged persistent-estrous rats following luteinizing hormone-releasing hormone agonist treatment: relation to plasma inhibin and 17 beta-estradiol.  

PubMed

Reproductive aging in female rats is associated with a transition from regular estrous cyclicity to an anovulatory condition described as persistent estrous (PE). This PE condition is characterized by continued follicular development with elevated circulating levels of estrogen and FSH. In an attempt to investigate further the age-related changes in neuroendocrine function of PE rats, we have developed a model through which the return of hypothalamic-pituitary and ovarian function can be assessed following the withdrawal of chronic LHRH agonist suppression. Subsequent to withdrawal of continuous (2.5 micrograms/h for 12 days) LHRH agonist [DTrp6, Pro9-NHEt]-LHRH (LHRH-AG) treatment, circulating FSH concentrations in PE rats increase and remain elevated with an apparent absence of ovarian negative feedback, and these rats fail to return to estrous cyclicity. In the present studies, estrogen administration induced significant decreases in FSH secretion in PE rats following withdrawal of LHRH-AG treatment and ovariectomy (OVX), suggesting that the negative feedback response to estrogen is maintained in PE females. However, progesterone administration 2 days later failed to elicit a positive feedback response of gonadotropin secretion in PE females prior to LHRH-AG treatment, serum inhibin and 17 beta-estradiol (E2) concentrations were similar in middle-aged PE rats and young cyclic females on proestrus, while FSH levels were significantly greater in PE rats. After withdrawal of LHRH-AG treatment, plasma FSH concentrations remained elevated in PE rats as compared to young rats despite similar increases in E2. However, increases in plasma inhibin were delayed and significantly attenuated in PE rats.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8439622

Matt, D W; Dahl, K D; Sarkissian, A; Sayles, T E

1993-02-01

35

In vitro Studies of Canine Mammary Tumors: Influence of 17-Beta-Estradiol and Progesterone on Cell Kinetics Parameters  

Microsoft Academic Search

Using an in vitro tritiated thymidine nuclear labeling followed by autoradiography, the effects of 17-?-estradiol (E2) or progesterone (Pg) were studied in 30 canine mammary tumors that were incubated and hormonally stimulated in vitro. In 10 of these tumors, the synthetic (S) phase duration was also measured in absence or in presence of E2, by using a double labeling with

Laurence Lespagnard; Robert Kiss; André Danguy; Nicole Legros; Georges Lenglet; Nicole Devleeschouwer; Robert Paridaens

1987-01-01

36

Hepatocyte Growth Factor System in the Mouse Uterus: Variation Across the Estrous Cycle and Regulation by 17-Beta-Estradiol and Progesterone1  

PubMed Central

Hepatocyte growth factor (HGF) and its receptor MET have been implicated in uterine development, pregnancy, and endometrial disorders, such as endometriosis and carcinoma. In vitro studies have shown that HGF acts as a mitogen, motogen, and morphogen on endometrial epithelial cells. However, the expression and regulation of HGF and MET in the uteri of different species remain obscure. The present study aimed to investigate the changes of HGF, MET, and HGF activator (HGFA) expression in the uterine endometrium during the estrous cycle in mice and to explore estrogen and progesterone regulation of their expression. MKI67 immunostaining was conducted to examine the association between HGF/MET expression and endometrial cell proliferation. Endometrial epithelial and stromal cells both expressed HGF, HGFA, and MET, but the cell type-specific patterns changed during the cycle. Estrogen and progesterone differentially regulated HGF, MET, and HGFA expression. Progesterone up-regulated their expression in the stroma and down-regulated their expression in the luminal epithelium, whereas 17-beta-estradiol down-regulated their expression in the glandular epithelium. The pattern of HGF/MET overall correlated with that of MKI67. In conclusion, HGF, HGFA, and MET expression in mouse uterus changes during the estrous cycle in a stage-, cell type-, and compartment-specific manner under the influence of estrogen and progesterone. HGF likely plays a role in cyclic endometrial remodeling, such as cell proliferation via autocrine/paracrine mechanisms in mouse uterus. PMID:20147731

Zhang, Xuan

2010-01-01

37

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

38

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...

39

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

40

Beneficial effect of 17{beta}-estradiol on hyperglycemia and islet {beta}-cell functions in a streptozotocin-induced diabetic rat model  

SciTech Connect

The modulating effect of estrogen on glucose homeostasis remains a controversial issue at present. In this study, we sought to determine the beneficial effect of 17{beta}-estradiol (E{sub 2}) on hyperglycemia and islet {beta}-cell functions in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were injected i.p. with STZ to induce a relatively mild diabetic condition. The rats were then treated with E{sub 2} orally at 500 {mu}g/kg body weight/day for 15 days to evaluate the modulating effect on hyperglycemia, insulin secretion, and islet {beta}-cell proliferation. E{sub 2} administration for 10 days significantly lowered plasma glucose levels, increased plasma insulin levels, and improved glucose tolerance by attenuating insulin response to oral glucose loading. These beneficial effects of E{sub 2} were accompanied by increases in islet number and volume, rate of islet cell proliferation, and the amount of insulin secreted. The growth-stimulatory effect of E{sub 2} on islet cells was linked to the functions of the estrogen receptor {alpha}. Notably, these protective effects of E{sub 2} on diabetic conditions were basically not observed when the STZ-treated rats had a more severe degree of islet damage and hyperglycemia. Taken together, we conclude that E{sub 2} can promote the regeneration of damaged pancreatic islets by stimulating {beta}-cell proliferation in diabetic rats, and this effect is accompanied by improvements in glucose tolerance and a decrease in plasma glucose levels. These findings suggest that oral administration of E{sub 2} may be beneficial in diabetic patients with an accelerated loss of islet {beta}-cells.

Yamabe, Noriko; Kang, Ki Sung; Zhu Baoting, E-mail: BTZhu@kumc.ed

2010-11-15

41

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...

42

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

43

An inter-laboratory study on the variability in measured concentrations of 17Beta-estradiol, testosterone and 11-ketotestosterone in white sucker: implications and recommendations  

EPA Science Inventory

Endocrine-disrupting chemicals (EDCs) are exogenous substances that can lead to impacts on the reproduction of fish sometimes by altering circulating concentrations of 17â-estradiol (E2), testosterone (T) and 11-ketotestosterone (11-KT). Common methods to measure steroids ...

44

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

45

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

46

Regulation of E2F-1 gene expression in human breast cancer cells  

E-print Network

in Human Breast Cancer Cells. (May 2005) Sharon Khethiwe Ngwenya, B.S., Oakwood College Chair of Advisory Committee: Dr. Stephen Safe 17beta-Estradiol induces E2F-1 gene expression in ZR-75 and MCF-7 human breast cancer cells. Analysis of the E2F... to -54 promoter region. This promoter region was also E2-responsive in ERalpha-positive ZR-75 cells; however, further analysis of the promoter showed that cooperative ERalpha/Sp1/NFY interactions were not necessary for hormone-induced transactivation...

Ngwenya, Sharon Khethiwe

2005-08-29

47

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

E-print Network

(Pimephales promelas) exposed to cattle feedlot effluent similarly displayed feminization, exhibiting diminished testosterone synthesis, altered head morphometrics and decreased testis size, indicating the potential risk associated with AFO runoff (Orlando... of altered reproductive fitness at 17?-estradiol concentrations around 1.0 ng L -1 (Irwin et al., 2001), while wild male fathead minnows (Pimephales promelas) displayed characteristics of demasculinization following exposure to effluent (Orlando et al...

Ullman, Jeffrey Layton

2007-09-17

48

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 ...

49

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...

50

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

2015-02-01

51

The Effect of 17beta Estradiol on Glut1 Expression In The Right Ventricle Of Rats With Severe Pulmonary Hypertension  

E-print Network

) is a devastating disease that is characterized by a rise of blood pressure in the blood vessels of the lung immunofluorescent dye. Nuclei are stained blue; cell membranes are stained green. Glut 1 quantification occurs via

Zhou, Yaoqi

52

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...

53

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.

54

Activation of growth factor secretion in tumorigenic states of breast cancer induced by 17 beta-estradiol or v-Ha-ras oncogene.  

PubMed Central

The MCF-7 human breast cancer cell line responds to estrogen stimulation in vitro by increased secretion of growth factors and proliferation and in vivo by tumor formation in the nude mouse. To test a possible role of growth factor secretion in expression of the tumorigenic phenotype, we stably transfected MCF-7 cells with the v-Ha-ras oncogene to produce the MCF-7ras cell line. The MCF-7ras cell line was tumorigenic in the absence of estrogens and secreted 3- to 5-fold elevated levels of a high molecular weight form of a type alpha transforming growth factor-like growth factor, type beta transforming growth factor, and insulin-like growth factor I. MCF-7ras cells, in contrast to MCF-7, were less sensitive to further growth stimulation by estrogen, type alpha transforming growth factor, and insulin-like growth factor I and showed little change in receptor levels for these hormones. Conditioned medium from MCF-7ras cells as well as two of its component growth factors (insulin-like growth factor I and type alpha transforming growth factor) replaced estrogen in stimulating MCF-7 colony formation in vitro. A coordinate increase in growth factor secretion by human breast cancer may contribute to its escape from estrogen dependence. PMID:2880347

Dickson, R B; Kasid, A; Huff, K K; Bates, S E; Knabbe, C; Bronzert, D; Gelmann, E P; Lippman, M E

1987-01-01

55

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

EPA Science Inventory

DNA arrays to monitor gene expression in rat blood and uterus following 17-b-estradiol exposure - biomonitoring environmental effects using surrogate tissues John C. Rockett, Robert J. Kavlock, Christy R. Lambright, Louise G. Parks, Judith E. Schmid, Vickie S. Wilson, Carmen W...

56

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

57

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...

58

Hepatic gene expression following consumption of soy protein isolate in female sprague-dawley rats differs from that produced by 17beta-estradiol treatment  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although soy foods have been recognized as an excellent source of protein, there have been recent concerns regarding potential adverse effects of isoflavone phytochemicals found in soy products, which are known to bind and activate estrogen receptors. Here we used global hepatic gene expression prof...

59

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...

60

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

61

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...

62

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...

63

Identification of two Isoforms of Vitelline Envelope Protein as Complementary Biomarkers to Vitellogenin in the Plasma of Rainbow Trout Exposed to 17beta-estradiol  

EPA Science Inventory

In the present study, protein markers of estrogenic exposure in rainbow trout (Oncorhynchus mykiss) were isolated and identified using innovative sample preparation techniques followed by advanced MS and bioinformatics approaches. Juvenile trout were administered 17ß-estradiol t...

64

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...

65

Inhibition of follicular development, vitellogenesis, and serum 17beta-estradiol concentrations in zebrafish following chronic, sublethal dietary exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.  

PubMed

The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent endocrine disruptor with the ability to affect several biologic processes, including reproduction. In fish, sublethal exposure to TCDD is known to modulate overall reproductive capacity, but impacts on follicular development and vitellogenesis are unknown. Here we show that chronic, dietary exposure to 0.08, 0.32, or 0.80 ng TCDD female(-1) day(-1) decreased egg production by more than 50% and that spawning success was reduced by as much as 96%. Serum estradiol concentrations were decreased more than twofold, accounting, in part, for observed decreases in serum vitellogenin concentrations by as much as 29%. Our data suggest that decreased egg production is likely the result of TCDD-mediated inhibition of the transition from pre-vitellogenic stage follicles to vitellogenic stage follicles, as well as the induction of follicular atresia. The majority of reproductive toxicity of TCDD is likely due to direct impacts on the ovary, yet histopathologic observations suggest liver toxicity could also contribute to observed impacts on vitellogenesis. Importantly, even when overall egg production is not significantly affected, our data show that subtle physiologic changes induced by TCDD can lead to altered gonadogenesis. This suggests that long-term exposure to very low concentrations of TCDD could greatly affect fecundity and reproductive success in fishes. PMID:16387744

Heiden, Tisha King; Carvan, Michael J; Hutz, Reinhold J

2006-04-01

66

Rapid enhancement of two-step wiring plasticity by estrogen and NMDA receptor activity  

Microsoft Academic Search

Cortical information storage requires combined changes in connectivity and synaptic strength between neurons, but the signaling mechanisms underlying this two-step wiring plasticity are unknown. Because acute 17beta-estradiol (E2) modulates cortical memory, we examined its effects on spine morphogenesis, AMPA receptor trafficking, and GTPase signaling in cortical neurons. Acute E2 application resulted in a rapid, transient increase in spine density, accompanied

Deepak P. Srivastava; Kevin M. Woolfrey; Kelly A. Jones; Cassandra Y. Shum; L. Leanne Lash; Geoffrey T. Swanson; Peter Penzes

2008-01-01

67

Distinct Regulation by Steroids of Messenger RNAs for FSHR and CYP19A1 in Bovine Granulosa Cells  

Microsoft Academic Search

Steroidal regulation of gene expression in follicular cells is not completely defined. Granulosa cells from 5 mm bovine follicles were cultured and treated and steady-state mRNA levels determined for FSHR (follicle-stimulating hormone receptor) and CYP19A1 (aromatase). Cells were treated for 5 days with (0.1-300 ng\\/ml) 17beta-estradiol (E2), testosterone (T), or 5alpha-dihydrotestosterone (DHT). FSHR mRNA was increased by T and DHT

Wenxiang Luo; Milo C. Wiltbank

2006-01-01

68

A Novel Method for the Evaluation of Mechanical Properties of Cancellous Bone in the Rat Distal Femur  

E-print Network

of the Testing Method ...................................................... 65 5.7 Effect of Estrogen on Tomographic and Mechanical Properties ........................... 66 5.8 Summary... to ovariectomy; the OVX+E2 group also received a subcutaneous implant of two 0.05 mg 17-beta estradiol 60-day slow release pellets (Innovative Research; Novi, Michigan, USA). The INTACT group served as the age-matched control group. Rats were housed...

Lucas, Matthew W.

2010-01-14

69

The Papillomavirus E2 Proteins  

PubMed Central

The papillomavirus E2 proteins are pivotal to the viral life cycle and have well characterized functions in transcriptional regulation, initiation of DNA replication and partitioning the viral genome. The E2 proteins also function in vegetative DNA replication, post-transcriptional processes and possibly packaging. This review describes structural and functional aspects of the E2 proteins and their binding sites on the viral genome. It is intended to be a reference guide to this viral protein. PMID:23849793

McBride, Alison A.

2013-01-01

70

E2f2 induces cone photoreceptor apoptosis independent of E2f1 and E2f3  

PubMed Central

The ‘activating' E2fs (E2f1-3) are transcription factors that potently induce quiescent cells to divide. Work on cultured fibroblasts suggested they were essential for division, but in vivo analysis in the developing retina and other tissues disproved this notion. The retina, therefore, is an ideal location to assess other in vivo adenovirus E2 promoter binding factor (E2f) functions. It is thought that E2f1 directly induces apoptosis, whereas other activating E2fs only induce death indirectly by upregulating E2f1 expression. Indeed, mouse retinoblastoma (Rb)-null retinal neuron death requires E2f1, but not E2f2 or E2f3. However, we report an entirely distinct mechanism in dying cone photoreceptors. These neurons survive Rb loss, but undergo apoptosis in the cancer-prone retina lacking both Rb and its relative p107. We show that while E2f1 killed Rb/p107 null rod, bipolar and ganglion neurons, E2f2 was required and sufficient for cone death, independent of E2f1 and E2f3. Moreover, whereas E2f1-dependent apoptosis was p53 and p73-independent, E2f2 caused p53-dependent cone death. Our in vivo analysis of cone photoreceptors provides unequivocal proof that E2f-induces apoptosis independent of E2f1, and reveals distinct E2f1- and E2f2-activated death pathways in response to a single tumorigenic insult. PMID:23558950

Chen, D; Chen, Y; Forrest, D; Bremner, R

2013-01-01

71

Binding of xenoestrogens to the sex steroid-binding protein in plasma from Arctic charr (Salvelinus alpinus L.).  

PubMed

A specific sex steroid-binding protein (SBP) is believed to be involved in regulation of circulating sex steroids, steroid delivery to target cells and intracellular signalling in sex steroid-sensitive tissues. In the present work, interactions between xenoestrogens and the plasma SBP in Arctic charr (Salvelinus alpinus L.) were determined using ligand-protein binding studies. The test compounds were all able to displace tritiated 17 beta-estradiol (E2) from the Arctic charr SBP (acSBP) in a competitive and dose-dependent manner. The acSBP affinities for the xenoestrogens ranged over several orders of magnitude (17 beta-estradiol>ethynylestradiol (EE2)>zearalenone (ZEA)>diethylstilbestrol (DES)>genistein (GEN)>bisphenol A (BPA), 4-t-octylphenol (OP)>o,p'-DDT, and dieldrin (DIN)), but were consistently lower than that of 17 beta-estradiol (about 4 x 10(2) -10(6)-fold less potent). The relative binding affinity (RBA) for selected chemicals were independent of both gender, age and maturation status, as well as variations of acSBP binding affinity. The affinity of endogenous steroids and estrogen mimics for the acSBP shows a high correlation to the affinity for the rainbow trout SBP, thus suggesting a phylogenetically conserved ligand-binding site between closely related species. Furthermore, it is argued that interaction with the acSBP- and SBP-mediated processes may introduce novel pathways for endocrine disruption, which may work in concert with the classical receptor-mediated effects. PMID:15556074

Tollefsen, K-E; Ovrevik, J; Stenersen, J

2004-10-01

72

The current perception thresholds in normal pregnancy.  

PubMed

The purpose of this study was to evaluate a quantitative analysis of the nociceptive threshold, using the current perception threshold (CPT), in women with normal pregnancies and to assess the relationship between nociceptive thresholds and ovarian sex steroids. The subjects consisted of 10 women with singleton pregnancies and 14 age-matched healthy female volunteers. The CPTs (5,250, and 2,000 Hz) of the dominant ankle section were determined with a Neurometer CPT/C (Neurotron, Baltimore, MD). Blood samples were collected after these examinations, and the total 17beta-estradiol (E(2)) and progesterone concentrations in sera were measured. The present findings clearly indicated that the CPTs at 2,000 Hz in women at term in normal pregnancies were significantly higher than those in nonpregnant women (p<0.05). At 5 and 250 Hz, there was no significant difference between pregnant and nonpregnant women. While there was also no significant correlation between CPT and E(2), and progesterone, there was significant correlation between CPT and the ratio of 17 beta-estradiol/progesterone (E(2)/P) at 2,000 Hz (p<0.05, r=0.67). We suggest from these data that changes in pressure sensitivity occur at term in pregnancy, and that other factors, possibly stimulated by both E(2) and progesterone, may play an important role in this change. PMID:12187366

Watanabe, Shoichi; Otsubo, Yasuo; Araki, Tsutomu

2002-08-01

73

Comparison of Fenton's oxidation and ozonation for removal of estrogens.  

PubMed

This study compares efficiency of Fenton's oxidation and ozonation of 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) as two possible processes for removal of estrogens from aqueous solutions. The effectiveness of Fenton's oxidative removal was studied at different ratios of reagents Fe2+:H2O2 (1:0.5; 1:10; 1:20; 1:33), where with some molar ratios up to 100% removal of E2 and EE2 was achieved in the first few minutes of reaction. The best molar ratio for E2 (17beta-estradiol) removal was 1:33, while in the case of EE2 the most efficient one was 1:20 ratio. Ozonation was much faster, because complete removal of estrogens was achieved in 30 seconds (pH approximately eaqual 6), but the time of ozonation was extended up to 60 minutes trying to decompose formed by-products, expressing estrogenic activity, detected by YES (Yeast Estrogen Screening) assay. The obtained results showed that the removal efficiency of estrogens from waters should be assessed by a combination of chemical analyses and bioassay. PMID:21977630

Nakrst, Jana; Bistan, Mirjana; Tisler, Tatjana; Zagorc-Koncan, Jana; Derco, Jan; Gotvajn, Andreja Zgajnar

2011-01-01

74

EAPP, a Novel E2F Binding Protein That Modulates E2F-dependent Transcription  

PubMed Central

E2F transcription factors play an essential role in cell proliferation and apoptosis and their activity is frequently deregulated in human cancers. In a yeast two-hybrid screen we identified a novel E2F-binding protein. Due to its strong phosphorylation we named it EAPP (e2F-associated phosphoprotein). EAPP is localized in the nucleus and interacts with E2F-1, E2F-2, and E2F-3, but not with E2F-4. Examination of a number of human cell lines revealed that EAPP levels are elevated in most transformed cells. Moreover, EAPP mRNA was detected in all investigated human tissues in varying amounts. EAPP is present throughout the cell cycle but disappears during mitosis. In transfection assays with reporters controlled by either an artificial E2F-dependent promoter or the murine thymidine kinase promoter, EAPP increased the activation caused by E2F-1 but not by E2F-4. Surprisingly, the promoter of the p14ARF gene, which was also activated by E2F-1, became repressed by EAPP. Overexpression of EAPP in U2OS cells resulted in a significant increase of cells in S-phase, whereas RNAi-mediated knock down of EAPP reduced the fraction of cells in S-phase. Taken together, these data suggest that EAPP modulates E2F-regulated transcription, stimulates proliferation, and may be involved in the malignant transformation of cells. PMID:15716352

Novy, Michael; Pohn, Regina; Andorfer, Peter; Novy-Weiland, Tina; Galos, Barbara; Schwarzmayr, Ludwig; Rotheneder, Hans

2005-01-01

75

The Astro-E2 Mission  

NASA Technical Reports Server (NTRS)

The Astro-E2 observatory is a rebuild of the original Astro-E observatory that was lost during launch in February 2000. It is scheduled for launch into low earth orbit on a Japanese M-V rocket in early 2005. The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, is developing the observatory with major contributions from the US. The three instruments on the observatory are the high-resolution x-ray spectrometer (the XRS) featuring a 30-pixel x-ray microcalorimeter array, a set of four CCD cameras (the XIS) and a combination photo-diode/scintillator detector system (the HXD) that will extend the band pass up to nearly 700 keV. A significant feature of Astro-E2 is that all of the instruments are coaligned and operated simultaneously. With its high spectral resolution and collecting area for spectroscopy above 1 keV, Astro-E2 should enable major discovery space and pioneer new technology for use in space. Prime areas for investigation are supernova remnants, active galaxies and the measurement of black hole properties via relativistically-broadened Fe-K emission galaxies. A number of enhancements have been made for the Astro-E2/XRS, including a higher resolution microcalorimeter array, ii mechanical cooler for longer cryogen life, and an improved in-flight calibration system. The Astro-E2/XIS has also been improved to include two back-side-illuminated CCDs to enhance the low energy response. Improvements have also been made to the x-ray mirrors used for both the XRS and XIS to sharpen the point spread function and reduce the effects of stray light. In this talk we will present the essential features of Astro-E2, paying particular attention to the enhancements, and describe the major scientific strengths of the observatory.

Kelley, Richard L.

2004-01-01

76

Cooperative binding of the E2 protein of bovine papillomavirus to adjacent E2-responsive sequences.  

PubMed Central

The DNA-binding properties of purified full-length E2 protein from bovine papillomavirus type 1 have been investigated by utilizing a quantitative gel shift analysis. By using a recombinant baculovirus which express the E2 open reading frame from the polyhedrin promoter, the full-length E2 protein was synthesized in insect cells and purified to homogeneity by using an E2 binding site (ACCGN4CGGT)-specific oligonucleotide column. The Kd of E2 binding to a 41-bp oligonucleotide containing a single binding site was found to be 2 x 10(-11) M. When two binding sites were included on an oligonucleotide, cooperative binding to these sites by the E2 protein was observed. A cooperativity parameter of 8.5 was determined for E2 binding to two sites. An 86-amino-acid peptide encompassing the C terminus of the protein retains the ability to bind E2 binding sites with a Kd of 4 x 10(-10) M but exhibits slight cooperativity of binding to two adjacent sites. A major determinant for cooperative binding of the full-length E2 protein is thus encoded by the N-terminal amino acids outside the minimal DNA binding domain. Images PMID:1848322

Monini, P; Grossman, S R; Pepinsky, B; Androphy, E J; Laimins, L A

1991-01-01

77

17?-Estradiol and Inflammation: Implications for Ischemic Stroke  

PubMed Central

Although typically associated with maintenance of female reproductive function, estrogens mediate physiological processes in nearly every body tissue, including the central nervous system. Numerous pre-clinical studies have shown that estrogen, specifically 17-beta-estradiol (17?-E2), protects the brain from ischemic injury following stroke. There are multiple mechanisms of 17?-E2’s neuroprotection, including activation of several neuroprotective pathways in the brain, but 17?-E2 also mediates the local and systemic immune response to ischemic stroke. This review summarizes the immune response to stroke, sex differences in stroke pathophysiology, and the role of estrogen as an immunomodulator. This review will focus almost entirely on the role of 17?-E2; however, there will be a brief review and comparison to other forms of estrogen. Understanding the immunomodulatory action of estrogens may provide an opportunity for the use of estrogens in treatment of stroke and other inflammatory disease. PMID:25276492

Petrone, Ashley B.; Simpkins, James W.; Barr, Taura L.

2014-01-01

78

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

Code of Federal Regulations, 2011 CFR

26 Internal Revenue 4 2011-04-01 2011-04-01...Section 1.367(e)-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY...provides rules requiring gain and loss recognition by a corporation on...

2011-04-01

79

Ultrafast Electron Pulse (e,2e) Processes  

NASA Astrophysics Data System (ADS)

Techniques for producing ultrafast electron pulses have been proposedootnotetextP. Baum and A.H. Zewail, Proc. Natl. Acad. Sci. U.S.A. 104, 18409 (2007); S.A. Hilbert, C. Ulterwaal, B. Barwick, H. Betalaan, and A.H. Zewail, ibid. 106, 10558 (2009). and prospects for using such pulses to image electron dynamics in the H atom and the hydrogen molecular ion have been theoretically demonstrated.ootnotetextH.-C. Shao and A.F. Starace, Phys. Rev. Lett. 105, 263201 (2010). The (e,2e) process provides a means to directly image the momentum distribution of the target.ootnotetextM.A. Coplan, J.H. Moore, and J.P. Doering, Rev. Mod. Phys. 66, 985 (1994). We explore here the possibility of observing the time dependence of a coherent superposition of target orbitals by means of the (e,2e) process with ultrafast incident electron pulses. Using scattering theory for a longitudinally coherent beam,ootnotetextF. Robicheaux, Phys. Rev. A 62, 062706 (2000). we find that the momentum distribution of a coherent state of the H atom can be retrieved.

Shao, Hua-Chieh; Starace, Anthony; Madsen, Lars

2012-06-01

80

Magnetic reversal in Dy-doped DyF e2/YF e2 superlattice films  

NASA Astrophysics Data System (ADS)

Reversible magnetic exchange springs can be formed in the magnetically soft YF e2 layers of epitaxial DyF e2/YF e2 multilayer films. Here we show that the insertion of just two monolayers of DyF e2 , placed directly in the middle of the YF e2 layers, brings about substantial changes. Results are presented for a Dy-doped (110)-oriented [DyFe2(60Å) /YFe2(120 Å ) /DyFe2(8 Å ) /YFe2(120 Å ) ] 15 multilayer film, measured at 100 K in fields of up to ±10 T. Using bulk magnetometry, micromagnetic modeling, and Dy-specific x-ray magnetic circular dichroism, it is shown that Dy doping substantially increases the number of spin states available to the system. Altogether 12 distinct spring states are identified which bring additional complexity to the magnetic reversal process. In particular, the exchange springs are no longer reversible, exhibiting magnetic exchange-spring collapse. Full and partial magnetic loops are presented for fields applied along the in-plane easy [001] axis and the in-plane hard [1 ¯10 ] axis. In particular, it is demonstrated that exchange-spring collapse is sharpest when the field is applied along a hard in-plane [1 ¯10 ] axis.

Stenning, G. B. G.; Bowden, G. J.; de Groot, P. A. J.; van der Laan, G.; Figueroa, A. I.; Bencok, P.; Steadman, P.; Hesjedal, T.

2015-03-01

81

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

82

E2F-1- and E2Ftr-mediated apoptosis: the role of DREAM and HRK  

PubMed Central

Abstract E2F-1-deleted mutant, ‘truncated E2F’ (E2Ftr, E2F-1[1–375]), lacking the carboxy-terminal transactivation domain, was shown to be more potent at inducing cancer cell apoptosis than wild-type E2F-1 (wtE2F-1; full-length E2F-1). Mechanisms by which wtE2F-1 and E2Ftr induce apoptosis, however, are not fully elucidated. Our study demonstrates molecular effects of pro-apoptotic BH3-only Bcl-2 family member Harakiri (Hrk) in wtE2F-1- and E2Ftr-induced melanoma cell apoptosis. We found that Hrk mRNA and Harakiri (HRK) protein expression was highly up-regulated in melanoma cells in response to wtE2F-1 and E2Ftr overexpression. HRK up-regulation did not require the E2F-1 transactivation domain. In addition, Hrk gene up-regulation and HRK protein expression did not require p53 in cancer cells. Hrk knockdown by Hrk siRNA was associated with significantly reduced wtE2F-1- and E2Ftr-induced apoptosis. We also found that an upstream factor, ‘downstream regulatory element antagonist modulator’ (DREAM), may be involved in HRK-mediated apoptosis in response to wtE2F-1 and E2Ftr overexpression. DREAM expression levels increased following wtE2F-1 and E2Ftr overexpression. Western blotting detected increased DREAM primarily in dimeric form. The homodimerization of DREAM resulting from wtE2F-1 and E2Ftr overexpression may contribute to the decreased binding activity of DREAM to the 3?-untranslated region of the Hrk gene as shown by electromobility shift assay. Results showed wtE2F-1- and E2Ftr-induced apoptosis is partially mediated by HRK. HRK function is regulated in response to DREAM. Our findings contribute to understanding the mechanisms that regulate wtE2F-1- and E2Ftr-induced apoptosis and provide insights into the further evaluation of how E2Ftr-induced apoptosis may be used for therapeutic gain. PMID:21564512

Hao, Hongying; Chen, Canming; Rao, Xiao-Mei; Gomez-Gutierrez, Jorge G; Zhou, H Sam; McMasters, Kelly M

2012-01-01

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 min 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.

2006-01-01

84

In vitro effect of sex steroids on cytotoxic activity of splenic macrophages in wall lizard (Hemidactylus flaviviridis).  

PubMed

Sexual dimorphism was observed in nitrite release and IL-1-like molecule production by splenic macrophages of the wall lizard (Hemidactylus flaviviridis), with a higher level in females than in males. Gonadectomy in both males and females resulted in a considerable increase of nitrite and IL-1-like molecule secretion, suggesting that the sex hormones inhibit cytotoxic activity of macrophages. To verify this assumption, dose- and time-related in vitro experiments with male and female sex steroids, dihydrotestosterone (DHT) and 17beta-estradiol (E(2)), respectively, were carried out. E(2) and DHT both significantly reduced the nitrite release and IL-1-like molecule production with an increase of dose or duration of treatment. PMID:11884072

Mondal, Soma; Rai, Umesh

2002-02-01

85

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

86

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

definition study in CY 2004. This study will produce system designs for wave energy conversion device powerE2I 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

87

RBM38 is a direct transcriptional target of E2F1 that limits E2F1-induced proliferation.  

PubMed

The E2F family of transcription factors plays a pivotal role in the regulation of cell proliferation in higher eukaryotes and is a critical downstream target of the tumor suppressor pRB. The pRB/E2F pathway is defective in most human tumors, resulting in deregulated E2F activity that induces uncontrolled cell proliferation, a hallmark of tumor cells. The RNA-binding protein RBM38, also named RNPC1, induces cell-cycle arrest in G(1), at least in part, via binding to and stabilizing the mRNA of the cyclin-dependent kinase inhibitor p21. RBM38 levels are altered in human cancer. Generally, RBM38 is overexpressed in various tumors; however, RBM38 mRNA levels are reduced in some breast tumors due to increased methylation of its promoter region. We show here that expression of RBM38 is regulated by E2F1. Specifically, RBM38 mRNA and protein levels are elevated upon activation of either exogenous E2F1 or endogenous E2Fs. Moreover, endogenous E2F1 binds the human RBM38 promoter and E2F1 knockdown reduces RBM38 levels. Our data raise the possibility that E2F1 together with E2F1-regulated RBM38 constitute a negative feedback loop that modulates E2F1 activity. In support of this, inhibition of RBM38 expression increases E2F1-mediated cell-cycle progression. Moreover, in human ovarian cancer, high correlation between expression of E2F1 and RBM38 is associated with increased survival. Overall, our data identify RBM38 as novel transcriptional target of E2F1 that restricts E2F1-induced proliferation. Furthermore, this negative feedback loop seems to restrict tumor aggressiveness, thereby promoting survival of patients with cancer. PMID:22798430

Feldstein, Orit; Ben-Hamo, Rotem; Bashari, Dana; Efroni, Sol; Ginsberg, Doron

2012-09-01

88

E2F transcription factor-1 regulates oxidative metabolism  

PubMed Central

Cells respond to stress by coordinating proliferative and metabolic pathways. Starvation restricts cell proliferative (glycolytic) and activates energy productive (oxidative) pathways. Conversely, cell growth and proliferation require increased glycolytic and decreased oxidative metabolism1. E2F transcription factors regulate both proliferative and metabolic genes2,3. E2Fs have been implicated in the G1/S cell cycle transition, DNA repair, apoptosis, development, and differentiation2-4. In pancreatic ?-cells, E2F1 gene regulation facilitated glucose-stimulated insulin secretion5,6. Moreover, mice lacking E2F1 (E2f1?/?) were resistant to diet-induced obesity4. Here, we show that E2F1 coordinates cellular responses by acting as a regulatory switch between cell proliferation and metabolism. In basal conditions, E2F1 repressed key genes that regulate energy homeostasis and mitochondrial functions in muscle and brown adipose. Consequently, E2f1?/? mice had a marked oxidative phenotype An association between E2F1 and pRb was required for repression of genes implicated in oxidative metabolism. This repression was alleviated in a constitutive active CDK4 (CDK4R24C) mouse model or when adaptation to energy demand was required. Thus, E2F1 represents a metabolic switch from oxidative to glycolytic metabolism that responds to stressful conditions. PMID:21841792

Lagarrigue, Sylviane; Aguilar, Victor; Clapé, Cyrielle; Chavey, Carine; Fritz, Vanessa; Casas, François; Apparailly, Florence; Auwerx, Johan; Fajas, Lluis

2013-01-01

89

Estrogens in streams associated with a concentrated animal feeding operation in upstate New York, USA.  

PubMed

Estrogens (estrone, 17 alpha-estradiol, 17beta-estradiol, and estriol) in three headwater streams within a concentrated animal feed operation (CAFO) site were monitored on a monthly base for a year (November 2006-October 2007). This CAFO is certified as organic (no growth promoters are administrated) and uses many Whole Farm Planning practices (e.g., 12-month-capacity waste storage lagoons). In general, estrogen concentrations in the streams are low (<1 ng L(-1)), and appeared to increase in spring, likely due to the mobilization of estrogens from soils upon snow melting/precipitation. Estrogens were detected in the streams during dry periods, indicating the contribution of estrogens from groundwater. The low concentrations of estrogens in stream water were probably the result of the long residence time (approximately 8 months) of the manure in the lagoons where most of the estrogens were degraded during storage. An analysis of liquid manure at the beginning of manure application season (after approximately 8 months storage) showed that over 99.8% of the estrogens potentially excreted by the cows were degraded. Moreover, about 90% of the estrogens in the liquid manure were associated with particulates larger than 0.7 microm. Batch experiments with spiked deuterium-labeled 17beta-estradiol-16,16,17-d(3) (d(3)-E2 beta) in the liquid manure demonstrated sorption of d(3)-E2 beta onto particulates in the liquid manure, and rapid degradation of d(3)-E2 beta in the aqueous phase and on particulates of the liquid manure under aerobic conditions. PMID:20172589

Zhao, Sherry; Zhang, Pengfei; Melcer, Michael E; Molina, John F

2010-04-01

90

Cooperative DNA binding of the bovine papillomavirus E2 transcriptional activator is antagonized by truncated E2 polypeptides.  

PubMed Central

Cooperative DNA binding of the bovine papillomavirus type 1 (BPV-1) E2 transcriptional activator (E2-TA) is thought to play a role in the transcriptional synergism of multiple E2-responsive DNA elements (J. Ham, N. Dostatni, J.-M. Gauthier, and M. Yaniv, Trends Biochem. Sci. 16:440-444, 1991). Binding-equilibrium considerations show that such involvement is unlikely, thereby suggesting that the E2-TA cooperative capacity may have evolved to play other, different roles. The role of cooperative interactions in the antagonistic activity of BPV-1-positive and BPV-1-negative E2 regulatory proteins was investigated by an in vitro quantitative gel shift assay. Viral repressor E2-TR, a truncated peptide encompassing the activator DNA-binding domain, possesses a small but measurable cooperative capacity. Furthermore, the minimal E2 DNA-binding domain interacts with the activator in a positive, heterocooperative manner. As a result, the in vitro competition of full-length and truncated E2 peptides appears to be (macroscopically) noncooperative. This heterocooperative effect is probably dominant in latently infected G0-G1 cells, in which repressor E2-TR is 10- to 20-fold more abundant than the activator. The data are discussed considering the possible role of homo- and heterocooperative DNA binding in E2-conditional gene expression. Images PMID:8394466

Monini, P; Blitz, I L; Cassai, E

1993-01-01

91

E2F-1 Directly Regulates Thrombospondin 1 Expression  

PubMed Central

Thrombospondin 1 (TSP1) has been shown to play a critical role in inhibiting angiogenesis, resulting in inhibition of tumor growth and metastases. To figure out TSP1's regulators will lead to reveal its biological function mechanistically. In this study, we show that E2F-1 could activate the transcription of TSP1 by both promoter assays and Northern blot. Analysis of various TSP1 promoter mutant constructs showed that a sequence located ?144/?137 up-stream of the transcriptional initiation site, related to the consensus E2F-responsive sequence, is necessary for the activation. In consistence with up-regulation of TSP-1 activity by over-expression of E2F-1, the knockdown of endogenous E2F-1 inhibited TSP-1 promoter activity significantly, implying that E2F-1 mediated regulation of TSP-1 is relevant in vivo. In addition, E2F-1 could also directly bind to the TSP1 promoter region covering ?144/?137 region as revealed by ChIP assays. Furthermore, the E2F-1-induced activation of TSP1 gene transcription is suppressed by pRB1 in a dose-dependent manner. Taken together, the results demonstrate that TSP1 is a novel target for E2F1, which might imply that E2F-1 can affect angiogenesis by modulating TSP1 expression. PMID:20976175

Ji, Wei; Zhang, Wei; Xiao, Wuhan

2010-01-01

92

Random Phage Mimotopes Recognized by Monoclonal Antibodies against the Pyruvate Dehydrogenase Complex-E2 (PDC-E2)  

Microsoft Academic Search

Dihydrolipoamide acetyltransferase, the E2 component of the pyruvate dehydrogenase complex (PDC-E2), is the autoantigen most commonly recognized by autoantibodies in primary biliary cirrhosis (PBC). We identified a peptide mimotope(s) of PDC-E2 by screening a phage-epitope library expressing random dodecapeptides in the pIII coat protein of fd phage using C355.1, a murine monoclonal antibody (mAb) that recognizes a conformation-dependent epitope in

Sanghoon Cha; Patrick S. C. Leung; Judy van de Water; Koichi Tsuneyama; Ruth E. Joplin; Aftab A. Ansari; Yasuni Nakanuma; Peter J. Schatz; Steve Cwirla; Luca E. Fabris; James M. Neuberger; M. Eric Gershwin; Ross L. Coppel

1996-01-01

93

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.

94

Comparative Analysis of E2F Family Member Oncogenic Activity  

Microsoft Academic Search

The E2F family of transcription factors consists of nine members with both distinct and overlapping functions. These factors are situated downstream of growth factor signaling cascades, where they play a central role in cell growth and proliferation through their ability to regulate genes involved in cell cycle progression. For this reason, it is likely that the members of the E2F

Chunxia Chen; Andrew D. Wells; Jacques Zimmer

2007-01-01

95

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

96

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

97

Random phage mimotopes recognized by monoclonal antibodies against the pyruvate dehydrogenase complex-E2 (PDC-E2).  

PubMed Central

Dihydrolipoamide acetyltransferase, the E2 component of the pyruvate dehydrogenase complex (PDC-E2), is the autoantigen most commonly recognized by autoantibodies in primary biliary cirrhosis (PBC). We identified a peptide mimotope(s) of PDC-E2 by screening a phage-epitope library expressing random dodecapeptides in the pIII coat protein of fd phage using C355.1, a murine monoclonal antibody (mAb) that recognizes a conformation-dependent epitope in the inner lipoyl domain of PDC-E2 and uniquely stains the apical region of bile duct epithelium (BDE) only in patients with PBC. Eight different sequences were identified in 36 phage clones. WMSYPDRTLRTS was present in 29 clones; WESYPFRVGTSL, APKTYVSVSGMV, LTYVSLQGRQGH, LDYVPLKHRHRH, AALWGVKVRHVS, KVLNRIMAGVRH and GNVALVSSRVNA were singly represented. Three common amino acid motifs (W-SYP, TYVS, and VRH) were shared among all peptide sequences. Competitive inhibition of the immunohistochemical staining of PBC BDE was performed by incubating the peptides WMSYPDRTLRTS, WESYPDRTLRTS, APKTYVSVSGMV, and AALWGVKVRHVS with either C355.1 or a second PDC-E2-specific mAb, C150.1. Both mAbs were originally generated to PDC-E2 but map to distinct regions of PDC-E2. Two of the peptides, although selected by reaction with C355.1, strongly inhibited the staining of BDE by C150.1, whereas the peptide APKTYVSVSGMV consistently inhibited the staining of C355.1 on biliary duct epithelium more strongly than the typical mitochondrial staining of hepatocytes. Rabbit sera raised against the peptide WMSYPDRTLRTS stained BDE of livers and isolated bile duct epithelial cells of PBC patients more intensively than controls. The rabbit sera stained all size ducts in normals, but only small/medium-sized ductules in PBC livers. These studies provide evidence that the antigen present in BDE is a molecular mimic of PDC-E2, and not PDC-E2 itself. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8855289

Cha, S; Leung, P S; Van de Water, J; Tsuneyama, K; Joplin, R E; Ansari, A A; Nakanuma, Y; Schatz, P J; Cwirla, S; Fabris, L E; Neuberger, J M; Gershwin, M E; Coppel, R L

1996-01-01

98

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...

99

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

100

The ancient function of RB-E2F Pathway: insights from its evolutionary history  

PubMed Central

Background The RB-E2F pathway is conserved in most eukaryotic lineages, including animals and plants. E2F and RB family proteins perform crucial functions in cycle controlling, differentiation, development and apoptosis. However, there are two kinds of E2Fs (repressive E2Fs and active E2Fs) and three RB family members in human. Till now, the detail evolutionary history of these protein families and how RB-E2F pathway evolved in different organisms remain poorly explored. Results We performed a comprehensive evolutionary analysis of E2F, RB and DP (dimerization partners of E2Fs) protein family in representative eukaryotic organisms. Several interesting facts were revealed. First, orthologues of RB, E2F, and DP family are present in several representative unicellular organisms and all multicellular organisms we checked. Second, ancestral E2F, RB genes duplicated before placozoans and bilaterians diverged, thus E2F family was divided into E2F4/5 subgroup (including repressive E2Fs: E2F4 and E2F5) and E2F1/2/3 subgroup (including active E2Fs: E2F1, E2F2 and E2F3), RB family was divided into RB1 subgroup (including RB1) and RBL subgroup (including RBL1 and RBL2). Third, E2F4 and E2F5 share more sequence similarity with the predicted E2F ancestral sequence than E2F1, E2F2 and E2F3; E2F4 and E2F5 also possess lower evolutionary rates and higher purification selection pressures than E2F1, E2F2 and E2F3. Fourth, for RB family, the RBL subgroup proteins possess lower evolutionary rates and higher purification selection pressures compared with RB subgroup proteins in vertebrates, Conclusions Protein evolutionary rates and purification selection pressures are usually linked with protein functions. We speculated that function conducted by E2F4/5 subgroup and RBL subgroup proteins might mainly represent the ancient function of RB-E2F pathway, and the E2F1/2/3 subgroup proteins and RB1 protein might contribute more to functional diversification in RB-E2F pathway. Our results will enhance the current understanding of RB-E2F pathway and will also be useful to further functional studies in human and other model organisms. Reviewers This article was reviewed by Dr. Pierre Pontarotti, Dr. Arcady Mushegian and Dr. Zhenguo Lin (nominated by Dr. Neil Smalheiser). PMID:20849664

2010-01-01

101

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

102

Advanced Stirling Convertor (ASC-E2) Characterization Testing  

NASA Technical Reports Server (NTRS)

Testing has been conducted on Advanced Stirling Convertors (ASCs)-E2 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 the operation of the ASRG during space missions

Williams, Zachary D.; Oriti, Salvatore M.

2012-01-01

103

Formulation of Ames 24E2 IR-black coating  

NASA Technical Reports Server (NTRS)

The formulation of Ames 24E2 IR-black coating and a rationale for the selection of its components are given. The objective was to make a very rough, very thick, and highly absorbing coating to attenuate the specular reflectance of telescope baffles at far-IR wavelengths. Application and curing instructions are also given. Outgassing measurements are quite low following a 24-hour radiative cure.

Smith, Sheldon M.

1991-01-01

104

E2-p7 Region of the Bovine Viral Diarrhea Virus Polyprotein: Processing and Functional Studies  

Microsoft Academic Search

The genes encoding pestivirus E2 and NS2-3 are separated by a sequence that encodes a small hydrophobic polypeptide with an apparent molecular mass of 6 to 7 kDa (p7). It has been shown that cleavage between E2 and p7 is incomplete, resulting in proteins E2-p7, E2, and p7. We found no precursor-product relationship between E2-p7 and E2, which indicates a

TAKASHI HARADA; NORBERT TAUTZ; HEINZ-JURGEN THIEL

2000-01-01

105

E2F-1 Functions in Mice to Promote Apoptosis and Suppress Proliferation  

Microsoft Academic Search

Members of the E2F transcription factor family (E2F-1–E2F-5) are believed to be critical positive regulators of cell cycle progression in eukaryotes although the in vivo functions of the individual E2Fs have not been elucidated. Mice were generated that lack E2F-1 and, surprisingly, these mice develop and reproduce normally. However, E2F-1?\\/? mice exhibit a defect in T lymphocyte development leading to

Seth J. Field; Fong-Ying Tsai; Frank Kuo; Ana M. Zubiaga; William G Kaelin; David M Livingston; Stuart H Orkin; Michael E Greenberg

1996-01-01

106

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

107

E2F1 and E2F2 induction in response to DNA damage preserves genomic stability in neuronal cells.  

PubMed

E2F transcription factors regulate a wide range of biological processes, including the cellular response to DNA damage. In the present study, we examined whether E2F family members are transcriptionally induced following treatment with several genotoxic agents, and have a role on the cell DNA damage response. We show a novel mechanism, conserved among diverse species, in which E2F1 and E2F2, the latter specifically in neuronal cells, are transcriptionally induced after DNA damage. This upregulation leads to increased E2F1 and E2F2 protein levels as a consequence of de novo protein synthesis. Ectopic expression of these E2Fs in neuronal cells reduces the level of DNA damage following genotoxic treatment, while ablation of E2F1 and E2F2 leads to the accumulation of DNA lesions and increased apoptotic response. Cell viability and DNA repair capability in response to DNA damage induction are also reduced by the E2F1 and E2F2 deficiencies. Finally, E2F1 and E2F2 accumulate at sites of oxidative and UV-induced DNA damage, and interact with ?H2AX DNA repair factor. As previously reported for E2F1, E2F2 promotes Rad51 foci formation, interacts with GCN5 acetyltransferase and induces histone acetylation following genotoxic insult. The results presented here unveil a new mechanism involving E2F1 and E2F2 in the maintenance of genomic stability in response to DNA damage in neuronal cells. PMID:25892555

Castillo, Daniela S; Campalans, Anna; Belluscio, Laura M; Carcagno, Abel L; Radicella, J Pablo; Cánepa, Eduardo T; Pregi, Nicolás

2015-04-18

108

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

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

Ameliorative effects of Anoectochilus formosanus extract on osteopenia in ovariectomized rats.  

PubMed

The purpose of this study was to determine ameliorative effects of crude aqueous extract of Anoectochilus formosanus (AFE) on osteopenia in ovariectomized (OVX) rats. First, all of the rats were divided into sham and OVX groups. The OVX rats were allowed to lose bone for 6 weeks. At 6 weeks post-OVX, the OVX rats were divided into four groups treated with water, 17beta-estradiol (30 microg/kg, daily s.c. injection) or AFE (0.5, 2 g/kg, daily, orally) for 12 weeks. In OVX rats, the increases of body weight and serum total cholesterol were significantly decreased by AFE or 17beta-estradiol treatment. In OVX rats, atrophy of uterus and vagina was preserved by treatment with 17beta-estradiol, but not by AFE. The decreased weight of pituitary was increased by treatment with both 17beta-estradiol and AFE. There were decreases in bone density and calcium content including the right femur and the fourth lumbar vertebra, when compared with the sham control rats. Treatment with either 17beta-estradiol or AFE ameliorated these changes induced by OVX. In addition, ovariectomy increased serum alkaline phosphatase levels. The increases were suppressed by the treatment with 17beta-estradiol and AFE. Our results demonstrated that AEF could ameliorate ovariectomy-induced osteopenia. PMID:11535369

Shih, C C; Wu, Y W; Lin, W C

2001-10-01

111

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

112

The effect of estrogen synthesis inhibition on hippocampal memory.  

PubMed

17-Beta-estradiol (E2) facilitates long term-potentiation (LTP) and increases spine synapse density in hippocampal neurons of ovariectomized rodents. Consistent with these beneficial effects on the cellular level, E2 improves hippocampus-dependent memory. A prominent approach to study E2 effects in rodents is the inhibition of its synthesis by letrozole, which reduces LTPs and spine synapse density. In the current longitudinal functional magnetic resonance imaging (fMRI) study, we translated this approach to humans and compared the impact of E2 synthesis inhibition on memory performance and hippocampal activity in post-menopausal women taking letrozole (n=21) to controls (n=24). In particular, we employed various behavioral memory paradigms that allow the disentanglement of hippocampus-dependent and -independent memory. Consistent with the literature on rodents, E2 synthesis inhibition specifically impaired hippocampus-dependent memory, however, this did not apply to the same degree to all of the employed paradigms. On the neuronal level, E2 depletion tended to decrease hippocampal activity during encoding, whereas it increased activity in the anterior cingulate and the dorsolateral prefrontal cortex. We thus infer that the inhibition of E2 synthesis specifically impairs hippocampal functioning in humans, whereas the increased prefrontal activity presumably reflects a compensatory mechanism, which is already known from studies on cognitive aging and Alzheimer's disease. PMID:25863445

Bayer, Janine; Rune, Gabriele; Schultz, Heidrun; Tobia, Michael J; Mebes, Imke; Katzler, Olaf; Sommer, Tobias

2015-06-01

113

HPV 16 E2 binding sites 1 and 2 become more methylated than E2 binding site 4 during cervical carcinogenesis.  

PubMed

E2 protein binding to the four E2 binding sites (E2BSs) at the long control region of Human Papillomavirus (HPV) 16/18 genome may exert either transcriptional activation/repression on E6 and E7 oncoproteins. Methylation status at the E2BSs may affect the relative binding of E2 protein to them. In this study, methylation percentage at E2BS 1, 2 (promoter-proximal), and 4 (promoter-distal) were assessed by pyrosequencing and compared among HPV 16/18-positive cervical cancer, high-grade, and low-grade Cervical Intraepithelial Neoplasia, Atypical Squamous Cells of Undetermined Significance, and normal cervical epithelium. HPV 16 E2BS1&2 were more methylated than HPV 16 E2BS4 in cervical cancer whereas in cervical premalignant lesions and normal epithelium, HPV 16 E2BS1&2 were less methylated than HPV 16 E2BS4. HPV 18 E2BS1&2 remained more methylated than E2BS4 in all histological groups. HPV 16 E2BS1&2 methylation increased from high-grade lesions to cervical cancer (P?E2BS4 methylation increased from low-grade to high-grade premalignant lesions (P?=?0.041). Both HPV 18 E2BS1&2 and E2BS4 methylation increased from low-grade to high-grade Cervical Intraepithelial Neoplasia (P?=?0.019 and 0.001 respectively) and further increased form high-grade lesions to cervical cancer (P?E2BS1&2 (for transcriptional repression of E6/E7 oncoproteins) became more heavily methylated than E2BS4 (for transcriptional activation of E6/E7) in cervical cancer, favouring the differential binding of E2 protein to E2BS4. Increasing methylation at HPV 16/18 E2BSs are potentially useful adjunctive molecular markers for predicting progression from low-grade to high-grade cervical premalignant lesions and from high-grade lesions to cervical cancer. J. Med. Virol. 87:1022-1033, 2015. © 2015 Wiley Periodicals, Inc. PMID:25648229

Leung, Tsin-Wah; Liu, Stephanie S; Leung, Rebecca C Y; Chu, Mandy M Y; Cheung, Annie N Y; Ngan, Hextan Y S

2015-06-01

114

Cytoprotective effect of prostaglandin E2 in irradiated rat ileum  

SciTech Connect

Radiation injury to the gastrointestinal tract is an infrequent but major clinical problem. Results of previous studies have shown that prostaglandins provide cytoprotection of the gastrointestinal mucosa against a variety of noxious agents, although, prior to this study, the protection against radiation exposure had not been documented. Exteriorized segment of Sprague-Dawley rat ileum was radiated with 10 and 15 Gy (/sup 137/Cs). One group of rats was pretreated with prostaglandin E2 one hour before and 24 hours after radiation injury. The rats were sacrificed three and five days following radiation injury. Morphometric measurement of mucosal thickness, villous height, crypt of Lieberkuehn height and number of mitoses per square millimeter swath of tissue were analyzed. Also, /sup 125/IUdR and /sup 3/HTdR were injected in a group of rats radiated with 15 Gy (/sup 137/Cs). /sup 125/IUdR counts per minute per milligram of dry weight and /sup 3/HTdR labeled cells were counted and analyzed. The morphometric measurements and radioactive labeled tissue counts suggest that prostaglandin E2 has a cytoprotective effect upon irradiated rat ileum. Speculations about the possible mechanism and usefulness of this observation are included.

Tomas-de la Vega, J.E.; Banner, B.F.; Hubbard, M.; Boston, D.L.; Thomas, C.W.; Straus, A.K.; Roseman, D.L.

1984-01-01

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

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

PubMed

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

2014-05-30

117

Estrogen protects the heart from ischemia-reperfusion injury via COX-2-derived PGI2.  

PubMed

There is an accumulating body of data to suggest that estrogen mediates its cardioprotective effects via cyclooxygenase activation and synthesis of prostaglandins (PG), specifically PGI2. We hypothesized that inhibition of COX-2 would prevent estrogen's cardioprotective effects after myocardial ischemia-reperfusion. Acute treatment with 17beta-estradiol (E2; 20 microg/rabbit) increased COX-2 protein expression and activity in the myocardium. To determine the effects of COX-2 inhibition on infarct size after E2 treatment, New Zealand white rabbits were anesthetized and administered the COX-2 inhibitor nimesulide (5 mg/kg) or vehicle intravenously 30 minutes before an intravenous injection of E2. Thirty minutes after estrogen treatment, the coronary artery was occluded for 30 minutes followed by 4 hours of reperfusion. E2 significantly decreased infarct size as a percent of area at risk when compared to vehicle (18.9 +/- 3.1 versus 47.0 +/- 4.1; P < 0.001). Pretreatment with nimesulide nullified the infarct size sparing effect of E2 (55.8 +/- 5.6). Treatment with the PGI2 receptor antagonist RO3244794 also abolished the protective effects of E2 (45.3 +/- 4.5). The results indicate that estrogen protects the myocardium from ischemia-reperfusion injury through increased production of COX-2-derived PGI2. The data indicate that selective COX-2 inhibitors might counteract the potential cytoprotective effects of estrogen in premenopausal or postmenopausal women. PMID:18806603

Booth, Erin Anne; Flint, RaShonda Renee; Lucas, Kathryn Louise; Knittel, Andrea Kathleen; Lucchesi, Benedict R

2008-09-01

118

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

119

Anaerobic biotransformation of estrogens.  

PubMed

Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-alpha-ethynylestradiol (EE2) and 17-beta-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 microg L-1 day-1), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-alpha-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-alpha-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments. PMID:16616321

Czajka, Cynthia P; Londry, Kathleen L

2006-08-31

120

Nuclear localization of ?-tubulin affects E2F transcriptional activity and S-phase progression  

PubMed Central

We show that the centrosome- and microtubule-regulating protein ?-tubulin interacts with E2 promoter binding factors (E2Fs) to modulate E2F transcriptional activity and thereby control cell cycle progression. ?-Tubulin contains a C-terminal signal that results in its translocation to the nucleus during late G1 to early S phase. ?-Tubulin mutants showed that the C terminus interacts with the transcription factor E2F1 and that the E2F1–?-tubulin complex is formed during the G1/S transition, when E2F1 is transcriptionally active. Furthermore, E2F transcriptional activity is altered by reduced expression of ?-tubulin or by complex formation between ?-tubulin and E2F1, E2F2, or E2F3, but not E2F6. In addition, the ?-tubulin C terminus encodes a DNA-binding domain that interacts with E2F-regulated promoters, resulting in ?-tubulin-mediated transient activation of E2Fs. Thus, we report a novel mechanism regulating the activity of E2Fs, which can help explain how these proteins affect cell cycle progression in mammalian cells.—Höög, G., Zarrizi, R., von Stedingk, K., Jonsson, K., Alvarado-Kristensson, M. Nuclear localization of ?-tubulin affects E2F transcriptional activity and S-phase progression. PMID:21788450

Höög, Greta; Zarrizi, Reihaneh; von Stedingk, Kristoffer; Jonsson, Kristina; Alvarado-Kristensson, Maria

2011-01-01

121

Triply differential (e,2e) studies of phenol  

SciTech Connect

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.

Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, MT 78600-000 (Brazil); Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Câmpus Poços de Caldas, MG (Brazil); Departamento de Física, UFJF, Juiz de Fora, 36036-330, MG (Brazil); Chiari, L.; Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Ali, E.; Madison, D. H. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Ning, C. G. [Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Nixon, K. L.; Lopes, M. C. A. [Departamento de Física, UFJF, Juiz de Fora, 36036-330, MG (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2014-09-28

122

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

123

E2F mediates enhanced alternative polyadenylation in proliferation  

PubMed Central

Background The majority of mammalian genes contain multiple poly(A) sites in their 3' UTRs. Alternative cleavage and polyadenylation are emerging as an important layer of gene regulation as they generate transcript isoforms that differ in their 3' UTRs, thereby modulating genes' response to 3' UTR-mediated regulation. Enhanced cleavage at 3' UTR proximal poly(A) sites resulting in global 3' UTR shortening was recently linked to proliferation and cancer. However, mechanisms that regulate this enhanced alternative polyadenylation are unknown. Results Here, we explored, on a transcriptome-wide scale, alternative polyadenylation events associated with cellular proliferation and neoplastic transformation. We applied a deep-sequencing technique for identification and quantification of poly(A) sites to two human cellular models, each examined under proliferative, arrested and transformed states. In both cell systems we observed global 3' UTR shortening associated with proliferation, a link that was markedly stronger than the association with transformation. Furthermore, we found that proliferation is also associated with enhanced cleavage at intronic poly(A) sites. Last, we found that the expression level of the set of genes that encode for 3'-end processing proteins is globally elevated in proliferation, and that E2F transcription factors contribute to this regulation. Conclusions Our results comprehensively identify alternative polyadenylation events associated with cellular proliferation and transformation, and demonstrate that the enhanced alternative polyadenylation in proliferative conditions results not only in global 3' UTR shortening but also in enhanced premature cleavage in introns. Our results also indicate that E2F-mediated co-transcriptional regulation of 3'-end processing genes is one of the mechanisms that links enhanced alternative polyadenylation to proliferation. PMID:22747694

2012-01-01

124

RBF Binding to both Canonical E2F Targets and Noncanonical Targets Depends on Functional dE2F/dDP Complexes  

PubMed Central

The retinoblastoma (RB) family of proteins regulate transcription. These proteins lack intrinsic DNA-binding activity but are recruited to specific genomic locations through interactions with sequence-specific DNA-binding factors. The best-known target of RB protein (pRB) is the E2F transcription factor; however, many other chromatin-associated proteins have been described that may allow RB family members to act at additional sites. To gain a perspective on the scale of E2F-dependent and E2F-independent functions, we generated genome-wide binding profiles of RBF1 and dE2F proteins in Drosophila larvae. RBF1 and dE2F2 associate with a large number of binding sites at genes with diverse biological functions. In contrast, dE2F1 was detected at a smaller set of promoters, suggesting that it overrides repression by RBF1/dE2F2 at a specific subset of targets. Approximately 15% of RBF1-bound regions lacked consensus E2F-binding motifs. To test whether RBF1 action at these sites is E2F independent, we examined dDP mutant larvae that lack any functional dE2F/dDP heterodimers. As measured by chromatin immunoprecipitation-microarray analysis (ChIP-chip), ChIP-quantitative PCR (qPCR), and cell fractionation, the stable association of RBF1 with chromatin was eliminated in dDP mutants. This requirement for dDP was seen at classic E2F-regulated promoters and at promoters that lacked canonical E2F-binding sites. These results suggest that E2F/DP complexes are essential for all genomic targeting of RBF1. PMID:22927638

Korenjak, Michael; Anderssen, Endre; Ramaswamy, Sridhar; Whetstine, Johnathan R.

2012-01-01

125

Comparative vitellogenic responses in three teleost species: extrapolation to in situ field studies.  

PubMed

Induction of vitellogenin (VTG) was compared among three teleostean species to determine their relative sensitivity of exposure to 17 beta-estradiol (E2). Japanese medaka (Oryzias latipes), sunshine bass (Morone saxatalis x Morone chrysops) and channel catfish (Ictalurus punctatus) were exposed to aqueous concentrations of E2 ranging from 10 to 100,000 ng/l for 21 days. Respective EC50 values for plasma VTG detected by western blot in medaka, catfish and bass were 200, 170 and 1560 ng E2/l. Since these EC50 values are based on VTG induction curves calculated relative to control values, they indicate differences in species' sensitivity to E2 exposure. Catfish and bass VTG responses obtained in laboratory exposures were compared to VTG responses previously observed with 21-day wastewater treatment plant effluent exposures. Plasma VTG induction in effluent-exposed fish ranged from 14 to 82% above reference values depending on species. Extrapolation of field responses with laboratory-exposed fish indicate catfish and bass were exposed to the equivalent of 27-240 ng E2/l in sewage effluent. PMID:11460689

Thompson, S; Tilton, F; Schlenk, D; Benson, W H

2000-01-01

126

Expression of functional aromatase in the epididymis: role of androgens and LH in modulation of expression and activity.  

PubMed

The primary source of 17beta-estradiol (E2) in the male is the testis, which expresses the enzyme complex aromatase that is involved in E2 biosynthesis. However, recent evidences suggest that the epididymis is also capable of E2 biosynthesis. Our results demonstrate the presence of cytochrome P450 aromatase (P450(AROM)) and 17beta-hydroxysteroid dehydrogenase I messenger ribonucleic acid (mRNA) in the caput and cauda regions of rat epididymis. The androgenic substrates testosterone and androstenedione could be utilized by the rat epididymal aromatase for E2 biosynthesis as assessed by radioimmunoassay. P450(AROM) expression is transcriptionally regulated in a tissue-specific manner by various factors including androgens and luteinizing hormone (LH). Androgens could positively modulate epididymal P450(AROM) mRNA levels as assessed by castration studies, treatment with flutamide or in vitro incubation of tissue minces with 5 alpha-dihydrotestosterone (DHT). Several extra-gonadal tissues including the epididymis are known to express LH receptors (LHR). Our study revealed a higher level of LHR mRNA expression in the cauda region compared to the caput. Caudal membrane extracts could bind human chorionic gonadotropin (hCG), which resulted in the production of cAMP. Interestingly, hCG could also regulate P450(AROM) mRNA expression in vitro and enhance E2 biosynthesis. Together our results highlight the presence of a functional aromatase in the epididymis that is subject to regulation by LH and androgens. PMID:16569475

Shayu, D; Rao, A J

2006-04-25

127

Estradiol-induced ezrin overexpression in ovarian cancer: a new signaling domain for estrogen.  

PubMed

We have for the first time exposed estrogen's role in the epithelial ovarian cancer (OVCA) metastatic cascade and discovered that it is related to the induction of ezrin over-expression. 17beta Estradiol (E2) was administered to SKOV3 (ERalpha>beta) and DOV13 (ERalphaE2 induced an invasive phenotype with translocation of ezrin to cell edges, including pseudopodia and ruffles. A strong correlation was found between ezrin expression and Matrigel penetration induced by E2. Increases in cell number and ezrin expression were confirmed by flask incubations. E2 stimulation of OVCA cell proliferation, motility and Matrigel penetration was dose-related and raloxifene or tamoxifen blocked E2's effect, supporting an ER action. This previously unreported effect of estrogen on ezrin expression may play a role in the clinical course of estrogen-sensitive cancers and other normal or diseased cell actions. PMID:15737688

Song, Joon; Fadiel, Ahmed; Edusa, Valentine; Chen, Zhaocong; So, John; Sakamoto, Hideki; Fishman, David A; Naftolin, Frederick

2005-03-18

128

Functional Interactions between 17?-Estradiol and Progesterone Regulate Autophagy during Acini Formation by Bovine Mammary Epithelial Cells in 3D Cultures  

PubMed Central

Mammary gland epithelium forms a network of ducts and alveolar units under control of ovarian hormones: 17-beta-estradiol (E2) and progesterone (P4). Mammary epithelial cells (MECs) cultured on reconstituted basement membrane (rBM) form three-dimensional (3D) acini composed of polarized monolayers surrounding a lumen. Using the 3D culture of BME-UV1 bovine MECs we previously demonstrated that autophagy was induced in the centrally located cells of developing spheroids, and sex steroids increased this process. In the present study we showed that E2 and P4 enhanced the expression of ATG3, ATG5, and BECN1 genes during acini formation, and this effect was accelerated in the presence of both hormones together. The stimulatory action of E2 and P4 was also reflected by increased levels of Atg5, Atg3, and LC3-II proteins. Additionally, the activity of kinases involved in autophagy regulation, Akt, ERK, AMPK, and mTOR, was examined. E2 + P4 slightly increased the level of phosphorylated AMPK but diminished phosphorylated Akt and mTOR on day 9 of 3D culture. Thus, the synergistic actions of E2 and P4 accelerate the development of bovine mammary acini, which may be connected with stimulation of ATGs expression, as well as regulation of signaling pathways (PI3K/Akt/mTOR; AMPK/mTOR) involved in autophagy induction. PMID:24895572

Zielniok, Katarzyna; Motyl, Tomasz

2014-01-01

129

Prostaglandin E2 mediates connecting tubule glomerular feedback.  

PubMed

Connecting tubule glomerular feedback (CTGF) is a mechanism in which Na reabsorption in the connecting tubule (CNT) causes afferent arteriole (Af-Art) dilation. CTGF is mediated by eicosanoids, including prostaglandins and epoxyeicosatrienoic acids; however, their exact nature and source remain unknown. We hypothesized that during CTGF, the CNT releases prostaglandin E2, which binds its type 4 receptor (EP4) and dilates the Af-Art. Rabbit Af-Arts with the adherent CNT intact were microdissected, perfused, and preconstricted with norepinephrine. CTGF was elicited by increasing luminal NaCl in the CNT from 10 to 80 mmol/L. We induced CTGF with or without the EP4 receptor blocker ONO-AE3-208 added to the bath in the presence of the epoxyeicosatrienoic acid synthesis inhibitor MS-PPOH. ONO-AE3-208 abolished CTGF (control, 9.4 ± 0.5; MS-PPOH+ONO-AE3-208, -0.6 ± 0.2 ?m; P<0.001; n=6). To confirm these results, we used a different, specific EP4 blocker, L161982 (10(-5) mol/L), that also abolished CTGF (control, 8.5 ± 0.9; MS-PPOH+L161982, 0.8 ± 0.4 ?m; P<0.001; n=6). To confirm that the eicosanoids that mediate CTGF are released from the CNT rather than the Af-Art, we first disrupted the Af-Art endothelium with an antibody and complement. Endothelial disruption did not affect CTGF (7.9 ± 0.9 versus 8.6 ± 0.6 ?m; P=NS; n=7). We then added arachidonic acid to the lumen of the CNT while maintaining zero NaCl in the perfusate. Arachidonic acid caused dose-dependent dilation of the attached Af-Art (from 8.6 ± 1.2 to 15.3 ± 0.7 ?m; P<0.001; n=6), and this effect was blocked by ONO-AE3-208 (10(-7) mol/L). We conclude that during CTGF, the CNT releases prostaglandin E2, which acts on EP4 on the Af-Art inducing endothelium-independent dilation. PMID:24060896

Ren, Yilin; D'Ambrosio, Martin A; Garvin, Jeffrey L; Wang, Hong; Carretero, Oscar A

2013-12-01

130

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

131

Inhalation Treatment of Pulmonary Fibrosis by Liposomal Prostaglandin E2  

PubMed Central

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and often fatal form of interstitial lung disease. We hypothesized that the local pulmonary delivery of prostaglandin E2 (PGE2) by liposomes can be used for the effective treatment of IPF. To test this hypothesis, we used a murine model of bleomycin-induced IPF to evaluate liposomes which carries PGE2 topically to the lungs. Animal survival, body weight, hydroxyproline content in the lungs, lung histology, mRNA and protein expression were studied. After inhalation delivery, liposomes accumulated predominately in the lungs. In contrast, intravenous administration led to the accumulation of liposomes mainly in kidney, liver, and spleen. Liposomal PGE2 prevented the disturbances in the expression of many genes associated with the development of IPF, substantially restricted inflammation and fibrotic injury in the lung tissues, prevented decrease in body weight, limited hydroxyproline accumulation in the lungs and virtually eliminated mortality of animals after intratracheal instillation of bleomycin. In summary, our data provide evidence that pulmonary fibrosis can be effectively treated by the inhalation administration of liposomal form of PGE2 into the lungs. The results of the present investigations make the liposomal form of PGE2 an attractive drug for the effective inhalation treatment of idiopathic pulmonary fibrosis. PMID:23228437

Ivanova, Vera; Garbuzenko, Olga B.; Reuhl, Kenneth R.; Reimer, David C.; Pozharov, Vitaly P.; Minko, Tamara

2013-01-01

132

Differential Stem and Progenitor Cell Trafficking by Prostaglandin E2  

PubMed Central

SUMMARY To maintain lifelong production of blood cells, hematopoietic stem cells (HSC) are tightly regulated by inherent programs and extrinsic regulatory signals received from their microenvironmental niche. Long-term repopulating HSC (LT-HSC) reside in several, perhaps overlapping, niches that produce regulatory molecules/signals necessary for homeostasis and increased output following stress/injury 1–5. Despite significant advances in specific cellular or molecular mechanisms governing HSC/niche interactions, little is understood about regulatory function within the intact mammalian hematopoietic niche. Recently, we and others described a positive regulatory role for Prostaglandin E2 (PGE2) on HSC function ex vivo 6,7. While exploring the role of endogenous PGE2 we unexpectedly observed hematopoietic egress after nonsteroidal anti-inflammatory drug (NSAID) treatment. Surprisingly, this was independent of the SDF-1/CXCR4 axis. Stem and progenitor cells were found to have differing mechanisms of egress, with HSC transit to the periphery dependent on niche attenuation and reduction in the retentive molecule osteopontin (OPN). Hematopoietic grafts mobilized with NSAIDs had superior repopulating ability and long-term engraftment. Treatment of non-human primates and healthy human volunteers confirmed NSAID-mediated egress in higher species. PGE2 receptor knockout mice demonstrated that progenitor expansion and stem/progenitor egress resulted from reduced EP4 receptor signaling. These results not only uncover unique regulatory roles for EP4 signaling in HSC retention in the niche but also define a rapidly translatable strategy to therapeutically enhance transplantation. PMID:23485965

Hoggatt, Jonathan; Mohammad, Khalid S.; Singh, Pratibha; Hoggatt, Amber F.; Chitteti, Brahmananda Reddy; Speth, Jennifer M.; Hu, Peirong; Poteat, Bradley A.; Stilger, Kayla N.; Ferraro, Francesca; Silberstein, Lev; Wong, Frankie K.; Farag, Sherif S.; Czader, Magdalena; Milne, Ginger L.; Breyer, Richard M.; Serezani, Carlos H.; Scadden, David T.; Guise, Theresa; Srour, Edward F.; Pelus, Louis M.

2013-01-01

133

Prostaglandin E2 Mediates Cough via the EP3 Receptor  

PubMed Central

Rationale: A significant population of patients with severe asthma and chronic obstructive pulmonary disease is less responsive to ?2-adrenoceptor agonists and corticosteroids, and there are possible safety issues concerning long-term use of these drugs. Inhaled prostaglandin E2 (PGE2) is antiinflammatory and a bronchodilator in patients with asthma, but it also causes cough. Objectives: We aimed to identify the receptor involved in PGE2-induced sensory nerve activation and cough using a range of in vitro and in vivo techniques. Methods: Depolarization of vagal sensory nerves (human, mouse, and guinea pig) was assessed as an indicator of sensory nerve acitivity. Cough was measured in a conscious guinea pig model. Measurements and Main Results: Using an extensive range of pharmacological tools, we identified that the EP3 receptor mediates PGE2-induced depolarization of sensory nerves in human, mouse, and guinea pig. Further supporting evidence comes from data showing that responses to PGE2 are virtually abolished in isolated vagus nerves from EP3-deficient mice (Ptger3?/?). Finally, we demonstrated the role of the EP3 receptor in vivo using a selective EP3 antagonist to attenuate PGE2-induced cough. Conclusions: Identification of the receptor mediating PGE2-induced cough represents a key step in developing a drug that is antiinflammatory and a bronchodilator but without unwanted side effects. PMID:19729667

Maher, Sarah A.; Birrell, Mark A.; Belvisi, Maria G.

2009-01-01

134

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

135

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

136

Prostanoid signaling: dual role for prostaglandin E2 in neurotoxicity  

PubMed Central

The prostanoids, a naturally occurring subclass of eicosanoids, are lipid mediators generated through oxidative pathways from arachidonic acid. These cyclooxygenase metabolites, consisting of the prostaglandins (PG), prostacyclin and tromboxane, are released in response to a variety of physiological and pathological stimuli in almost all organs, including the brain. They are produced by various cell types and act upon targeted cells via specific G protein-coupled receptors. The existence of multiple receptors, cross-reactivity and coupling to different signal transduction pathways for each prostanoid, collectively establish their diverse effects. Notably, these effects can occur in functionally opposing directions within the same cell or organ. Prostaglandin E2 (PGE2) is the most versatile prostanoid because of its receptors, E Prostanoid (EP) receptor subtypes 1 through 4, its biological heterogeneity and its differential expression on neuronal and glial cells throughout the central nervous system. Since PGE2 plays an important role in processes associated with various neurological diseases, this review focuses on its dual neuroprotective and neurotoxic role in EP receptor subtype signaling pathways in different models of brain injury. PMID:21376752

Milatovic, Dejan; Montine, Thomas J.; Aschner, Michael

2011-01-01

137

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

138

Identification of E2F target genes that are rate limiting for dE2F1-dependent cell proliferation  

PubMed Central

Background Microarray studies have shown that the E2F transcription factor influences the expression of many genes but it is unclear how many of these targets are important for E2F-mediated control of cell proliferation. Results We assembled a collection of mutant alleles in 44 dE2F1-dependent genes and tested whether these could modify visible phenotypes caused by the tissue-specific depletion of dE2F1. More than half of the mutant alleles dominantly enhanced de2f1-dsRNA phenotypes suggesting that the in vivo functions of dE2F1 can be limited by the reduction in the level of expression of many different targets. Unexpectedly, several mutant alleles suppressed de2f1-dsRNA phenotypes. One of the strongest of these suppressors was Orc5. Depletion of ORC5 increased proliferation in cells with reduced dE2F1 and specifically elevated the expression of dE2F1-regulated genes. Importantly, these effects were independent of dE2F1 protein levels, suggesting that reducing the level of ORC5 did not interfere with the general targeting of dE2F1. Conclusions We propose that the interaction between ORC5 and dE2F1 may reflect a feedback mechanism between replication initiation proteins and dE2F1 that ensures that proliferating cells maintain a robust level of replication proteins for the next cell cycle. PMID:22972499

Herr, Anabel; Longworth, Michelle; Ji, Jun-Yuan; Korenjak, Michael; MacAlpine, David M.; Dyson, Nicholas J.

2013-01-01

139

The E2F transcriptional network: old acquaintances with new faces  

Microsoft Academic Search

The E2 factor (E2F) family of transcription factors are downstream targets of the retinoblastoma protein. E2F factors have been known for several years to be important regulators of S-phase entry. Recent studies have improved our understanding of the molecular mechanisms of action used by this transcriptional network. In addition, they have given us an appreciation of the fact that E2F

Desssislava K Dimova; Nicholas J Dyson

2005-01-01

140

Tumor Induction and Tissue Atrophy in Mice Lacking E2F-1  

Microsoft Academic Search

The retinoblastoma tumor suppressor protein (pRB) is a transcriptional repressor that regulates gene expression by physically associating with transcription factors such as E2F family members. Although pRB and its upstream regulators are commonly mutated in human cancer, the physiological role of the pRB–E2F pathway is unknown. To address the function of E2F-1 and pRB\\/E2F-1 complexes in vivo, we have produced

Lili Yamasaki; Tyler Jacks; Roderick Bronson; Evelyne Goillot; Ed Harlow; Nicholas J Dyson

1996-01-01

141

The CDK4-pRB-E2F1 pathway controls insulin secretion  

E-print Network

by glucose through the insulin pathway, ultimately resulting in E2F1 activation and consequently in Kir6The CDK4-pRB-E2F1 pathway controls insulin secretion Jean-Sébastien Annicotte1, 2, 7 , Emilie the control of -cell number the CDK4-pRB-E2F1 pathway has a role in -cell function. We show here that E2F1

Boyer, Edmond

142

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

143

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

144

Hydrogen sulfide inhibits preoptic prostaglandin E2 production during endotoxemia.  

PubMed

Hydrogen sulfide (H(2)S) is a gaseous neuromodulator endogenously produced in the brain by the enzyme cystathionine ?-synthase (CBS). We tested the hypothesis that H(2)S acts within the anteroventral preoptic region of the hypothalamus (AVPO) modulating the production of prostaglandin (PG) E(2) (the proximal mediator of fever) and cyclic AMP (cAMP). To this end, we recorded deep body temperature (Tb) of rats before and after pharmacological modulation of the CBS-H(2)S system combined or not with lipopolysaccharide (LPS) exposure, and measured the levels of H(2)S, cAMP, and PGE(2) in the AVPO during systemic inflammation. Intracerebroventricular (icv) microinjection of aminooxyacetate (AOA, a CBS inhibitor; 100 pmol) did not affect basal PGE(2) production and Tb, but enhanced LPS-induced PGE(2) production and fever, indicating that endogenous H(2)S plays an antipyretic role. In agreement, icv microinjection of a H(2)S donor (Na(2)S; 260 nmol) reduced the LPS-induced PGE(2) production and fever. Interestingly, we observed that the AVPO levels of H(2)S were decreased following the immunoinflammatory challenge. Furthermore, fever was associated with decreased levels of AVPO cAMP and increased levels of AVPO PGE(2). The LPS-induced decreased levels of cAMP were reduced to a lesser extent by the H(2)S donor. The LPS-induced PGE(2) production was potentiated by AOA (the CBS inhibitor) and inhibited by the H(2)S donor. Our data are consistent with the notion that the gaseous messenger H(2)S synthesis is downregulated during endotoxemia favoring PGE(2) synthesis and lowering cAMP levels in the preoptic hypothalamus. PMID:23153577

Kwiatkoski, Marcelo; Soriano, Renato N; Araujo, Rebeca M; Azevedo, Leopoldo U; Batalhao, Marcelo E; Francescato, Heloísa D C; Coimbra, Terezila M; Carnio, Evelin C; Branco, Luiz G S

2013-02-01

145

Prostaglandin E2 increases the skeletal response to mechanical loading  

NASA Technical Reports Server (NTRS)

The study tested the influence of prostaglandin E2 (PGE2) on the skeletal response to increased in vivo mechanical loading through a four-point bending device. One hundred and twenty Sprague-Dawley female rats (6 months old, 354 +/- 34 g) were divided into 12 groups to accommodate all possible combinations of doses of loads (25, 30, or 35 N) and PGE2 (0, 0.1, 0.3, or 1 mg/kg). Rats received subcutaneous injections of PGE2 daily and in vivo loading of the right tibia every Monday, Wednesday, and Friday for four weeks. Histomorphometric analysis of the periosteal and endocortical surfaces following in vivo dual fluorochrome labeling was performed on both the loaded region of the right tibial diaphysis and a similar region of the left tibial diaphysis. Without PGE2, the threshold for loading to stimulate bone formation was 30 N (peak strain 1360 mu epsilon) at the periosteal surface and 25 N (peak strain 580 mu epsilon) at the endocortical surface. Without loading, the minimum dose of PGE2 to stimulate bone formation at all surfaces was 1 mg/kg/day. When 1 mg/kg/day PGE2 was combined with the minimum effective load, an additive effect of PGE2 and loading on bone formation was observed at the endocortical surface, but a synergistic effect was noted at the periosteal surface. No combined effect of ineffective doses of loading and PGE2 was found. A synergistic effect at peak strains of approximately 1625 mu epsilon on the periosteal surface could suggest either the involvement of locally produced growth factors or autoregulation of endogenous synthesis of PGE2 by exogenously administered PGE2.

Tang, L. Y.; Cullen, D. M.; Yee, J. A.; Jee, W. S.; Kimmel, D. B.

1997-01-01

146

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

147

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

148

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

149

Suppression of newborn natural killer cell activity by prostaglandin E2  

SciTech Connect

The effect of prostaglandin E2 on natural killer cell activity of cord blood was examined. Natural killer cell activity, determined by chromium 51 release, was significantly reduced after prostaglandin E2 (1 microgram/ml) treatment. Prostaglandin E2 has been found to enhance the cellular spread of herpesvirus. Thus prostaglandins may enhance viral infections indirectly by suppressing natural killer cell activity.

Milch, P.O.; Salvatore, W.; Luft, B.; Baker, D.A.

1988-10-01

150

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 of 1910/09) · Course website: on blackboard (or on my home page) #12;Imperial College London ­ EEE 2L1, Instrumentation, ... · Areas of human activity: Industrial, Consumer, Biomedical, ... #12;Imperial College London

Papavassiliou, Christos

151

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

152

Estrogen and progesterone play pivotal roles in endothelial progenitor cell proliferation  

PubMed Central

Background It has been previously suggested that angiogenesis occurs during the menstrual cycle. Moreover, a rise in uterine blood flow is largely maintained by vasodilatation and substantial increases in angiogenesis. It is known that estradiol (E2) and progesterone (P4) are involved in angiogenesis. Recently, endothelial progenitor cells (EPCs) were found to be involved in neovascularization; however, their roles in uterine neovascularization have not been well characterized. We hypothesized that E2- or P4-mediated EPC proliferation plays important roles in uterine neovascularization during the menstrual cycle. Methods The number of EPCs in peripheral blood from subjects in the menstrual phase (n = 12), follicular phase (n = 8), and luteal phase (n = 16), was measured using flow cytometry. Peripheral blood mononuclear cells (PBMCs) were cultured for seven days with or without 17beta-estradiol (E2beta) or P4, followed by assessment of EPC proliferation based upon the uptake of acetylated low density lipoprotein (LDL) and lectin. The expression of estrogen receptor (ER) or progesterone receptor (PR) in EPCs was also evaluated using real-time PCR. Results E2beta and P4 significantly increased the proliferation of EPCs derived from the peripheral blood of subjects in menstrual phase, but not subjects in the luteal phase. In addition, the expression level of ERalpha was markedly higher than ERbeta in EPCs derived from women in menstrual phase. Conclusions EPC proliferation is induced during the menstrual phase and proliferation can be affected by estrogen through ERalpha activation. PMID:22252173

2012-01-01

153

Novel locally active estrogens accelerate cutaneous wound healing. A preliminary study.  

PubMed

New 17beta-estradiol (E2) derivatives 1-11 were synthesized from an estrone derivative by addition of organometallic reagents prepared from protected alpha,omega-alkynols and further elaboration of the addition products. The estrogenic activity of these novel compounds was determined using in vitro binding competition assay and transactivation analysis. Among the E2 derivatives synthesized, compound 2 showed the highest transactivation potency and was therefore tested for its ability to modulate cutaneous wound healing in vivo. Compound 2's ability to accelerate wound healing in ovariectomized mice and decrease the production of inflammatory molecules was comparable to that of E2. However, the activity of compound 2 was not superimposable to E2 with regard to the cells involved in the wound repairing process. When locally administered, compound 2 did not show any systemic activity on ER. This class of compounds with clear beneficial effects on wound healing and suitable for topical administration may lead to the generation of innovative drugs for an area of unmet clinical need. PMID:19718805

Brufani, Mario; Ceccacci, Francesca; Filocamo, Luigi; Garofalo, Barbara; Joudioux, Roberta; La Bella, Angela; Leonelli, Francesca; Migneco, Luisa M; Bettolo, Rinaldo Marini; Farina, Paolo M; Ashcroft, Gillian S; Routley, Claire; Hardman, Matthew; Meda, Clara; Rando, Gianpaolo; Maggi, Adriana

2009-01-01

154

The E2F2 Transcription Factor Sustains Hepatic Glycerophospholipid Homeostasis in Mice  

PubMed Central

Increasing evidence links metabolic signals to cell proliferation, but the molecular wiring that connects the two core machineries remains largely unknown. E2Fs are master regulators of cellular proliferation. We have recently shown that E2F2 activity facilitates the completion of liver regeneration after partial hepatectomy (PH) by regulating the expression of genes required for S-phase entry. Our study also revealed that E2F2 determines the duration of hepatectomy-induced hepatic steatosis. A transcriptomic analysis of normal adult liver identified “lipid metabolism regulation” as a major E2F2 functional target, suggesting that E2F2 has a role in lipid homeostasis. Here we use wild-type (E2F2+/+) and E2F2 deficient (E2F2?/?) mice to investigate the in vivo role of E2F2 in the composition of liver lipids and fatty acids in two metabolically different contexts: quiescence and 48-h post-PH, when cellular proliferation and anabolic demands are maximal. We show that liver regeneration is accompanied by large triglyceride and protein increases without changes in total phospholipids both in E2F2+/+ and E2F2?/? mice. Remarkably, we found that the phenotype of quiescent liver tissue from E2F2?/? mice resembles the phenotype of proliferating E2F2+/+ liver tissue, characterized by a decreased phosphatidylcholine to phosphatidylethanolamine ratio and a reprogramming of genes involved in generation of choline and ethanolamine derivatives. The diversity of fatty acids in total lipid, triglycerides and phospholipids was essentially preserved on E2F2 loss both in proliferating and non-proliferating liver tissue, although notable exceptions in inflammation-related fatty acids of defined phospholipid classes were detected. Overall, our results indicate that E2F2 activity sustains the hepatic homeostasis of major membrane glycerolipid components while it is dispensable for storage glycerolipid balance. PMID:25396754

Maldonado, Eduardo N.; Delgado, Igotz; Furland, Natalia E.; Buqué, Xabier; Iglesias, Ainhoa; Aveldaño, Marta I.; Zubiaga, Ana; Fresnedo, Olatz; Ochoa, Begoña

2014-01-01

155

Human proteome-scale structural modeling of E2-E3 interactions exploiting interface motifs.  

PubMed

Ubiquitination is crucial for many cellular processes such as protein degradation, DNA repair, transcription regulation, and cell signaling. Ubiquitin attachment takes place via a sequential enzymatic cascade involving ubiquitin activation (by E1 enzymes), ubiquitin conjugation (by E2 enzymes), and ubiquitin substrate tagging (by E3 enzymes). E3 ligases mediate ubiquitin transfer from E2s to substrates and as such confer substrate specificity. Although E3s can interact and function with numerous E2s, it is still unclear how they choose which E2 to use. Identifying all E2 partners of an E3 is essential for inferring the principles guiding E2 selection by an E3. Here we model the interactions of E3 and E2 proteins in a large, proteome-scale strategy based on interface structural motifs, which allows elucidation of (1) which E3s interact with which E2s in the human ubiquitination pathway and (2) how they interact with each other. Interface analysis of E2-E3 complexes reveals that loop L1 of E2s is critical for binding; the residue in the sixth position in loop L1 is widely utilized as an interface hot spot and appears indispensible for E2 interactions. Other loop L1 residues also confer specificity on the E2-E3 interactions: HECT E3s are in contact with the residue in the second position in loop L1 of E2s, but this is not the case for the RING finger type E3s. Our modeled E2-E3 complexes illuminate how slight sequence variations in E2 residues may contribute to specificity in E3 binding. These findings may be important for discovering drug candidates targeting E3s, which have been implicated in many diseases. PMID:22149024

Kar, Gozde; Keskin, Ozlem; Nussinov, Ruth; Gursoy, Attila

2012-02-01

156

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

PubMed

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. PMID:24811899

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

2014-06-21

157

Induction of labour with prostaglandin E2 tablets.  

PubMed

This study evaluates the efficacy and safety of PGE2 (prostaglandin E2) tablets for induction of labor in term pregnancy (38 to 42 weeks). 47 women (21 nullipara and 26 multiparae; ages 19 to 29 for nulliparae and 21 to 39 for multiparae) were studied; all were clinically normal according to the criteria of Thiery et al (1971), had intact membranes and mean Bishop scores (Bishop, 1964) of 7 for the nulliparae and 6.6 for the multiparae. In the parous group, the number of previous births ranged from 1 to 5. An initial dose of 0.5 mg PGE2 (1 tablet) was given to all except 1 patient who was given a 0.25 mg PGE2 as a test dose. A second dose of PGE2 was given if after 60 minutes, the recorded myometrial activity was less than 150 Montevideo Units. Subsequent doses of PGE2 (0.5 to 2.0 mg) were given at approximately 2-hourly intervals. Fetal scalp blood sample was collected at full cervical dilatation. 31 patients had spontaneous delivery while 16 patients (11 nulliparae and 5 multiparae) had to have vacuum extraction. The infants were assessed biochemically and clinically by Apgar scores at 1 and 5 minutes. Induction was successful in all except in a 23-year old obese nulliparous female at 40 weeks gestation who had a Bishop score of 5. This patient was given oxytocin infusion 27 hours after the first dose of PGE2; the baby was born following an easy vacuum extraction. Maternal morbidity included 1 to 3 episodes of vomiting in 8 of 21 nulliparae and 3 of 26 parous patients; elevated blood pressure during labor in 2 normotensive parous patients; postpartum hemorrhage which was easily controlled in 1 nullipara; and retained placenta in 1. Test dose to delivery interval ranged from 2 hours and 37 minutes to 18 hours and 29 minutes for the nulliparae and from 1 hour and 57 minutes to 9 hours and 13 minutes for the parous patients. The infants were in satisfactory condition at birth. PMID:4824688

Thiery, M; Sian, A Y; De Hemptinne, D; Derom, R; Martens, C; Van Kets, H V; Amy, J J

1974-04-01

158

E2 protein cage as a multifunctional nanoplatform  

NASA Astrophysics Data System (ADS)

Caged protein systems such as viral capsids, heat shock proteins, and ferritin are spherical structures that occur naturally in living organisms and are a growing class of biomimetic templates used to create new materials in nanotechnology. Such systems have been proposed as general drug carriers since they form highly symmetric nanoscale architectures that offer the potential to be tailored according to the desired application. Within this framework, this dissertation focuses on the design and development of a new drug delivery nanoplatform based on the E2 subunit of the pyruvate dehydrogenase protein from Bacillus stearothermophilus. This scaffold forms a 25-nm nanocapsule structure with a hollow cavity. We produced a variant of this protein consisting only of the structural core, and found the thermostability of this self-assembled scaffold to be unusually high, with an onset unfolding temperature of 81.1 +/- 0.9°C and an apparent midpoint unfolding temperature of 91.4 +/- 1.4°C. To evaluate the potential of this scaffold for encapsulation of guest molecules in the internal cavity, we made variants which altered the physicochemical properties of the hollow internal surface. These mutants, yielding up to 240 mutations within this cavity, assembled into correct architectures and exhibited high thermostability that was also comparable to the wild-type scaffold. To show the applicability of this scaffold we coupled two drug-like small molecules to the internal cavity. We also developed a new strategy for encapsulation of small hydrophobic drug molecules. This method is based on hydrophobic differences between the interior cavity and the external buffer to nucleate drug-like agents inside the protein cage. We demonstrate that internal mutations can introduce non-native functionality and enable molecular encapsulation within the cavity while still retaining the dodecahedral structure. Another surface amenable to modifications is the interface between subunits. Such a region was modified to introduce pH-dependent scaffold disassembly ability to assist drug release upon endocytosis inside the cells. Moreover, we demonstrated that modulation of the pH at which disassembly occurs can be achieved by modulation of electrostatic interactions through mutagenesis or changing ionic strength. Together, these results demonstrate the potential of our scaffold as a robust nanoscale platform for biomedical applications.

Dalmau Mallorqui, Merce

159

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

160

EWS-FLI1 employs an E2F switch to drive target gene expression  

PubMed Central

Cell cycle progression is orchestrated by E2F factors. We previously reported that in ETS-driven cancers of the bone and prostate, activating E2F3 cooperates with ETS on target promoters. The mechanism of target co-regulation remained unknown. Using RNAi and time-resolved chromatin-immunoprecipitation in Ewing sarcoma we report replacement of E2F3/pRB by constitutively expressed repressive E2F4/p130 complexes on target genes upon EWS-FLI1 modulation. Using mathematical modeling we interrogated four alternative explanatory models for the observed EWS-FLI1/E2F3 cooperation based on longitudinal E2F target and regulating transcription factor expression analysis. Bayesian model selection revealed the formation of a synergistic complex between EWS-FLI1 and E2F3 as the by far most likely mechanism explaining the observed kinetics of E2F target induction. Consequently we propose that aberrant cell cycle activation in Ewing sarcoma is due to the de-repression of E2F targets as a consequence of transcriptional induction and physical recruitment of E2F3 by EWS-FLI1 replacing E2F4 on their target promoters. PMID:25712098

Schwentner, Raphaela; Papamarkou, Theodore; Kauer, Maximilian O.; Stathopoulos, Vassilios; Yang, Fan; Bilke, Sven; Meltzer, Paul S.; Girolami, Mark; Kovar, Heinrich

2015-01-01

161

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

162

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

163

Novel retinoblastoma mutation abrogating the interaction to E2F2/3, but not E2F1, led to selective suppression of thyroid tumors.  

PubMed

Mutant mouse models are indispensable tools for clarifying gene functions and elucidating the pathogenic mechanisms of human diseases. Here, we describe novel cancer models bearing point mutations in the retinoblastoma gene (Rb1) generated by N-ethyl-N-nitrosourea mutagenesis. Two mutations in splice sites reduced Rb1 expression and led to a tumor spectrum and incidence similar to those observed in the conventional Rb1 knockout mice. The missense mutant, Rb1(D326V/+) , developed pituitary tumors, but thyroid tumors were completely suppressed. Immunohistochemical analyses of thyroid tissue revealed that E2F1, but not E2F2/3, was selectively inactivated, indicating that the mutant Rb protein (pRb) suppressed thyroid tumors by inactivating E2F1. Interestingly, Rb1(D326V/+) mice developed pituitary tumors that originated from the intermediate lobe of the pituitary, despite selective inactivation of E2F1. Furthermore, in the anterior lobe of the pituitary, other E2F were also inactivated. These observations show that pRb mediates the inactivation of E2F function and its contribution to tumorigenesis is highly dependent on the cell type. Last, by using a reconstitution assay of synthesized proteins, we showed that the D326V missense pRb bound to E2F1 but failed to interact with E2F2/3. These results reveal the effect of the pRb N-terminal domain on E2F function and the impact of the protein on tumorigenesis. Thus, this mutant mouse model can be used to investigate human Rb family-bearing mutations at the N-terminal region. PMID:25088905

Toki, Hideaki; Inoue, Maki; Minowa, Osamu; Motegi, Hiromi; Saiki, Yuriko; Wakana, Shigeharu; Masuya, Hiroshi; Gondo, Yoichi; Shiroishi, Toshihiko; Yao, Ryoji; Noda, Tetsuo

2014-10-01

164

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

165

Constitutive E2F1 Overexpression Delays Endochondral Bone Formation by Inhibiting Chondrocyte Differentiation  

PubMed Central

Longitudinal bone growth results from endochondral ossification, a process that requires proliferation and differentiation of chondrocytes. It has been shown that proper endochondral bone formation is critically dependent on the retinoblastoma family members p107 and p130. However, the precise functional roles played by individual E2F proteins remain poorly understood. Using both constitutive and conditional E2F1 transgenic mice, we show that ubiquitous transgene-driven expression of E2F1 during embryonic development results in a dwarf phenotype and significantly reduced postnatal viability. Overexpression of E2F1 disturbs chondrocyte maturation, resulting in delayed endochondral ossification, which is characterized by reduced hypertrophic zones and disorganized growth plates. Employing the chondrogenic cell line ATDC5, we investigated the effects of enforced E2F expression on the different phases of chondrocyte maturation that are normally required for endochondral ossification. Ectopic E2F1 expression strongly inhibits early- and late-phase differentiation of ATDC5 cells, accompanied by diminished cartilage nodule formation as well as decreased type II collagen, type X collagen, and aggrecan gene expression. In contrast, overexpression of E2F2 or E2F3a results in only a marginal delay of chondrocyte maturation, and increased E2F4 levels have no effect. These data are consistent with the notion that E2F1 is a regulator of chondrocyte differentiation. PMID:12724423

Scheijen, Blanca; Bronk, Marieke; van der Meer, Tiffany; Bernards, René

2003-01-01

166

Defensive roles of (E)-2-alkenals and related compounds in heteroptera.  

PubMed

We examined whether shared volatiles found in various heteropteran species and developmental stages function to repel predators. The nymphal dorsal abdominal gland secretions of Riptortus pedestris (Heteroptera: Alydidae) and Thasus acutangulus (Heteroptera: Coreidae), and the metathoracic scent gland secretion of Euschistus biformis (Heteroptera: Pentatomidae) adults were identified by gas chromatography/mass spectrometry (GC/MS). (E)-2-Hexenal, 4-oxo-(E)-2-hexenal (4-OHE), and (E)-2-octenal were found in all three species and deemed likely candidates for repelling predators. In addition to (E)-2-alkenals, the adult E. biformis secreted (E)-2-hexenyl acetate, (E)-2-octenyl acetate, and four hydrocarbons. We evaluated the potential predator repellent properties of these compounds and compound blends against a generalist, cosmopolitan insect predator, the Chinese praying mantid (Mantodea: Mantidae: Tenodera aridifolia sinensis). Mantids that experienced (E)-2-hexenal, (E)-2-octenal, and (E)-2-octenyl acetate moved away from the site of interaction, while 4-OHE and (E)-2-hexenyl acetate did not affect mantid behavior. The compound blends did not have additive or synergistic repellency effects on predator behavior. Compound repellency was not related to compound volatility. Instead, the repellent effect is likely related to predator olfaction, and the affinity of each compound to receptors on the antennae. Our results also suggest the repellents might intensify the visual defensive signals of aposematism (T. acutangulus nymphs) and mimicry (R. pedestris nymphs) in heteropteran bugs. PMID:23054031

Noge, Koji; Prudic, Kathleen L; Becerra, Judith X

2012-08-01

167

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

168

The regulatory E2 proteins of human genital papillomaviruses are pro-apoptotic.  

PubMed

Cervical carcinomas are frequently associated with infection by human papillomaviruses (HPVs). These viruses encode two oncogenes E6 and E7, which promote cell proliferation and immortalization. The viral E2 protein represses transcription of the E6/E7 oncogenes and activates viral DNA replication together with the viral E1 helicase. The E2 protein is specifically inactivated in HPV18-associated carcinoma, suggesting that it may prevent carcinogenic progression. Indeed, E2 was shown to exhibit a strong anti-proliferative action when ectopically expressed in cervical carcinoma cells, as it induces both G1 cell cycle arrest and cell death by apoptosis. While the cell cycle arrest is due to E2-mediated transcriptional repression of the viral oncogenes, the induction of apoptosis appears to be an autonomous function of E2. The amino-terminal transactivation domain (TAD) of the E2 protein is required for its pro-apoptotic activity, but transcriptional transactivation is not involved. E2 induces apoptosis through the extrinsic pathway, involving the initiator caspase 8. In addition, E2 is cleaved by caspases during apoptosis, providing an example of an apoptotic inducer, which is itself a target for caspase cleavage. The cleaved E2 protein exhibits an enhanced apoptotic activity, suggesting that it may participate in an amplification loop. This article reviews our current knowledge of the pro-apoptotic activity of the oncogenic papillomavirus E2 proteins, and discusses the implications for the viral vegetative cycle. PMID:14585548

Blachon, S; Demeret, C

2003-08-01

169

Altered E2 glycoprotein of Sindbis virus and its use in complementation studies.  

PubMed Central

We have detected a Sindbis virus variant that contains a smaller-molecular-weight form of the viral glycoprotein E2. The molecular weight of the PE2 precursor and the glycosylation pattern of the smaller E2 are normal, thus indicating that this E2 is formed by an aberrant proteolytic cleavage. The altered E2 was detected in an RNA+ temperature-sensitive mutant that was defective in proteolytic cleavage, but the abnormal PE2-to-E2 reaction could be separated from the ts mutation and is not itself a temperature-sensitive defect. We used the variant E2 as a marker to monitor the complementation reaction between an RNA+ and an RNA- mutant and discovered that complementation was not reciprocal; the RNA defect was corrected by the RNA+ mutant gene products but the RNA+ defect was not complemented by any RNA- gene products. Other studies have shown that the smaller E2 is not preferentially selected during viral maturation and budding. No significant changes have been detected in the biological activity of virions with this altered E2 protein. Comparison of the electrophoretic migration of the E1 and E2 Sindbis viral glycoproteins in a two-dimensional polyacrylamide slab gel system that was first run in the absence of sulfhydryl-reducing reagent and then with beta-mercaptoethanol indicated that the mobility of E1, but not that of E2, was significantly altered by reduction. Images PMID:650737

Bracha, M; Schlesinger, M J

1978-01-01

170

E2A suppresses invasion and migration by targeting YAP in colorectal cancer cells  

PubMed Central

Background E2A gene, which encodes two basic helix–loop–helix (bHLH) transcription factors E12 and E47, has been identified as regulator of B lymphoid hematopoiesis and suppressor of lymphoma. E47 protein was found to decrease E-cadherin expression and induce epithelial-mesenchymal transition (EMT). However, the role of E2A in colorectal cancer (CRC) metastasis is still elusive. Methods qRT-PCR and semi-qRT-PCR were performed to determine mRNA level of E2A in CRC specimens and colorectal cancer cells. RNAi was employed to downregulate E2A expression and subsequent protein level change was evaluated by immunoblot. Cell invasion and migration capacity were detected by transwell assay using cell culture inserts with or without basement membrane matrix, respectively. Results E2A expression was decreased in metastatic CRC tissues. Invasion and migration assays showed downregulation of E2A increased metastatic capacity of CRC cells while forced expression of E12 or E47 could offset this effect. Both E12 and E47 suppressed EMT induced by E2A downregulation. Moreover, Yes-Associated Protein (YAP) was a downstream target of E2A and suppression of YAP inhibited the pro-migration/invasion of E2A deficiency. Conclusion Our results suggest that E2A suppresses CRC cell metastasis, at least partially if not all, by inhibiting YAP expression. PMID:24369055

2013-01-01

171

E2F6 Associates with BRG1 in Transcriptional Regulation  

PubMed Central

The E2F6 protein functions as an Rb-independent repressor of gene transcription. We have previously provided evidence suggesting a role for E2F6 in repression of E2F-responsive genes at S phase. Here, we have identified BRG1, the ATPase subunit of the SWI/SNF chromatin-remodeling complex, as an E2F6 interacting protein. Immunoprecipitation experiments demonstrate that BRG1 binds specifically to E2F6 and E2F4 but not the activator E2Fs. E2F6 was also able to interact with BAF155, a BRG1-associated factor, in the SWI/SNF complex. Chromatin immunoprecipitation assays demonstrate the binding of BRG1 coincident with E2F6 on G1/S gene promoters during S phase. Collectively, our studies suggest that E2F6 may recruit BRG1 in transcriptional regulation of genes important for G1/S phase transition of the cell cycle. PMID:23082233

Leung, Janet Y.; Nevins, Joseph R.

2012-01-01

172

Disrupted Organization of RFamide Pathways in the Hypothalamus Is Associated with Advanced Puberty in Female Rats Neonatally Exposed to Bisphenol A1  

PubMed Central

ABSTRACT Hypothalamic neurons, which produce the kisspeptin family of peptide hormones (Kp), are critical for initiating puberty and maintaining estrous cyclicity by stimulating gonadotropin-releasing hormone (GnRH) release. Conversely, RFamide-related peptide-3 (RFRP3) neurons inhibit GnRH activity. It has previously been shown that neonatal exposure to bisphenol A (BPA) can alter the timing of female pubertal onset and induce irregular estrous cycles or premature anestrus. Here we tested the hypothesis that disrupted ontogeny of RFamide signaling pathways may be a mechanism underlying advanced puberty. To test this, we used a transgenic strain of Wistar rats whose GnRH neurons express enhanced green fluorescent protein. Pups were exposed by daily subcutaneous injection to vehicle, 17beta-estradiol (E2), 50 ?g/kg BPA, or 50 mg/kg BPA, from Postnatal Day (PND) 0 through PND 3, and then cohorts were euthanized on PNDs 17, 21, 24, 28, and 33 (5–8 animals per age per exposure; males were collected on PNDs 21 and 33). Vaginal opening was advanced by E2 and 50 ?g/kg BPA. On PND 28, females exposed to E2 and 50 ?g/kg BPA had decreased RFRP-3 fiber density and contacts on GnRH neurons. RFRP3 perikarya were also decreased in females exposed to 50 ?g/kg BPA. Data suggest that BPA-induced premature puberty results from decreased inhibition of GnRH neurons. PMID:22572997

Losa-Ward, Sandra M.; Todd, Karina L.; McCaffrey, Katherine A.; Tsutsui, Kazuyoshi; Patisaul, Heather B.

2012-01-01

173

Lack of activity of cadmium in in vitro estrogenicity assays  

SciTech Connect

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 (ER{alpha}) was observed at cadmium concentrations between 5 x 10{sup -7} M and 5 x 10{sup -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{sup -11} M and 1 x 10{sup -5} M. However, in both assays, cadmium led to a reduction of the effects of 17{beta}-estradiol (E2). Treatment of MCF-7 human breast cancer cells with 1 x 10{sup -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.

Silva, Elisabete [Centre for Toxicology, School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)]. E-mail: elisabete.silva@pharmacy.ac.uk; Lopez-Espinosa, Maria Jose [School of Medicine, Hospital Clinico, University of Granada, 18071-Granada (Spain); Molina-Molina, Jose-Manuel [School of Medicine, Hospital Clinico, University of Granada, 18071-Granada (Spain); Fernandez, Marieta [School of Medicine, Hospital Clinico, University of Granada, 18071-Granada (Spain); Olea, Nicolas [School of Medicine, Hospital Clinico, University of Granada, 18071-Granada (Spain); Kortenkamp, Andreas [Centre for Toxicology, School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)

2006-10-01

174

Reproductive and thyroid hormone profiles in captive Western fence lizards (Sceloporus occidentalis) after a period of brumation.  

PubMed

Seasonal fluctuation in serum concentrations of sex steroid (testosterone [T] and 17beta-estradiol [E(2)]) and thyroid (triiodothyronine [T(3)] and thyroxine [T(4)]) hormones was determined in captive Western fence lizards (Sceloporus occidentalis). Samples were collected from male and female breeding pairs weekly for a 4-month period after their emergence from artificial brumation. Circulating levels of E(2) corresponded with the expected vitellogenic and ovulatory cycles in females, and surprisingly, E(2) in males followed a similar pattern, indicating a possible role in breeding behavior. Serum T was elevated in male lizards for the first 6 weeks after emergence from brumation, possibly related to an increase in the onset of active spermatogenesis. Thyroid hormones showed little cyclical activity throughout the breeding period, with the exception of small increases of T(3) at weeks 8 and 16, possibly implying an active role of this hormone with ovulation in females. Overall, these baseline hormone data are not only useful in developing this animal as a laboratory reptile model for assessment of endocrine-mediated toxicity, but also of value for understanding herpetological endocrinology and for application in the conservation of threatened species. Zoo Biol 27:36-48, 2008. (c) 2007 Wiley-Liss, Inc. PMID:19360602

Brasfield, Sandra M; Talent, Larry G; Janz, David M

2008-01-01

175

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

176

Long-term responses of the mouse uterus to neonatal diethylstilbestrol treatment and to later sex hormone exposure.  

PubMed

The effects of ovariectomy at 1 month of age and continuous 17 beta-estradiol (E2) and/or progesterone (P) replacement on the uterus of BALB/cCrgl mice neonatally treated with diethylstilbestrol [(DES) CAS: 56-53-1; alpha-alpha'-diethyl-4,4'-stilbenediol] or sesame oil were recorded after 1, 4, 7, and 10 months of treatment. DES-exposed uteri were found to be hypoplastic, less responsive to the growth-promoting effects of E2, and more likely to develop smooth muscle abnormalities after continuous hormonal treatment than similarly treated control uteri. Neonatal DES treatment led to leukocytic infiltration, disruption in the organization of the inner circular smooth muscle layer, and development of a population of epithelial cells believed to respond to later E2 treatment by proliferation and stratification (squamous metaplasia). Qualitative and quantitative responses to continuous P treatment and the development of cystic glandular hyperplasia and adenomyosis were found to be unaltered by neonatal DES administration. The relevance of these results to the problems of uterine abnormalities observed in women exposed to DES in utero is discussed. PMID:3855473

Ostrander, P L; Mills, K T; Bern, H A

1985-01-01

177

Fundulus heteroclitus gonadotropins.5: Small scale chromatographic fractionation of pituitary extracts into components with different steroidogenic activities using homologous bioassays.  

PubMed

Fractionation and characterization of gonadotropins (GtH) from Fundulus heteroclitus pituitary extracts were carried out using a biocompatible liquid chromatographic procedure (Pharmacia FPLC system). Chromatographic fractions were monitored for gonadotropic activities (induction of oocyte maturation and steroid production) using homologous follicle bioassays in vitro. Size-exclusion chromatography eluted gonadotropic activity in one major protein peak (Mr approximately 30,000). Anion-exchange and hydrophobic-interaction chromatography (HIC) yielded two distinct peaks of 17beta-estradiol (E2)- and 17alpha-hydroxy,20beta-dihydroprogesterone (DHP)-promoting activity with associated oocyte maturation. Two-dimensional chromatography (chromatofocusing followed by HIC) resolved pituitary extracts into two active fractions; both induced E2 synthesis, but one was relatively poor in eliciting DHP and testosterone production. Thus, using homologous bioassays, at least two quantitatively different gonadotropic (steroidogenic) activities: an E2-promoting gonadotropin (GtH I-like) and a DHP-promoting gonadotropin (GtH II-like), which has a lower isoelectric point but greater hydrophobicity than the former, can be distinguished from F. heteroclitus pituitaries by a variety of chromatographic procedures. This study complements previous biochemical and molecular data in F. heteroclitus and substantiates the duality of GtH function in a multiple-spawning teleost. PMID:15040801

Lin, Yu-Wai Peter; Petrino, Teresa R; Wallace, Robin A

2004-03-24

178

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

179

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

PubMed

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

180

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

181

TFDP3 was expressed in coordination with E2F1 to inhibit E2F1-mediated apoptosis in prostate cancer.  

PubMed

TFDP3 has been previously identified as an inhibitor of E2F molecules. It has been shown to suppress E2F1-induced apoptosis dependent P53 and to play a potential role in carcinogenesis. However, whether it indeed helps cancer cells tolerate apoptosis stress in cancer tissues remains unknown. TFDP3 expression was assessed by RT-PCR, in situ hybridization and immunohistochemistry in normal human tissues, cancer tissues and prostate cancer tissues. The association between TFDP3 and E2F1 in prostate cancer development was analyzed in various stages. Apoptosis was evaluated with annexin-V and propidium iodide staining and flow-cytometry. The results show that, in 96 samples of normal human tissues, TFDP3 could be detected in the cerebrum, esophagus, stomach, small intestine, bronchus, breast, ovary, uterus, and skin, but seldom in the lung, muscles, prostate, and liver. In addition, TFDP3 was highly expressed in numerous cancer tissues, such as brain-keratinous, lung squamous cell carcinoma, testicular seminoma, cervical carcinoma, skin squamous cell carcinoma, gastric adenocarcinoma, liver cancer, and prostate cancer. Moreover, TFDP3 was positive in 23 (62.2%) of 37 prostate cancer samples regardless of stage. Furthermore, immunohistochemistry results show that TFDP3 was always expressed in coordination with E2F1 at equivalent expression levels in prostate cancer tissues, and was highly expressed particularly in samples of high stage. When E2F1 was extrogenously expressed in LNCap cells, TFDP3 could be induced, and the apoptosis induced by E2F1 was significantly decreased. It was demonstrated that TFDP3 was a broadly expressed protein corresponding to E2F1 in human tissues, and suggested that TFDP3 is involved in prostate cancer cell survival by suppressing apoptosis induced by E2F1. PMID:24406621

Ma, Yueyun; Xin, Yijuan; Li, Rui; Wang, Zhe; Yue, Qiaohong; Xiao, Fengjing; Hao, Xiaoke

2014-03-10

182

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

183

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

184

Human papillomavirus E2 protein associates with nuclear receptors to stimulate nuclear receptor- and E2-dependent transcriptional activations in human cervical carcinoma cells.  

PubMed

Steroid hormones are proposed to act with human papillomaviruses (HPVs) as cofactors in the etiology of cervical cancer. Steroid hormone-activated nuclear receptors (NRs) are thought to bind to specific DNA sequences within transcriptional regulatory regions on the HPV DNA to either increase or suppress transcription of dependent genes. HPV-induced immortalization of epithelial cells usually requires integration of the viral DNA into the host cell genome. The integration event causes disruption of the E2 gene: the E2 protein is a transcription factor that regulates expression of the E6 and E7 oncoproteins by binding to four sites within the viral long control region (LCR). Our previous study suggested that E6 and E7 oncoproteins both directly bind to some NRs and serve as their cofactors. Here, we provide several lines of evidence demonstrating that the E2 protein is an NR coactivator through its physical interaction with NRs. In our study, the NR coactivator function of HPV E2 protein in human cervical carcinoma cells was independent of the type of E2, HPV transformation and the p53 status. Our observations also provide evidence suggesting regulatory mechanisms for the LCR involving interaction between the E2 protein and NRs in HeLa cells. PMID:17092759

Wu, Meng-Hsun; Chan, James Yi-Hsin; Liu, Pei-Yao; Liu, Shu-Ting; Huang, Shih-Ming

2007-01-01

185

Distinct Roles for E2F Proteins in Cell Growth Control and Apoptosis  

Microsoft Academic Search

E2F transcription activity is composed of a family of heterodimers encoded by distinct genes. Through the overproduction of each of the five known E2F proteins in mammalian cells, we demonstrate that a large number of genes encoding proteins important for cell cycle regulation and DNA replication can be activated by the E2F proteins and that there are distinct specificities in

James Degregori; Gustavo Leone; Alexander Miron; Laszlo Jakoi; Joseph R. Nevins

1997-01-01

186

TRANSCRIPTION: Chromatin Control--a Place for E2F and Myc to Meet  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. The transcription factor E2F switches on target genes during the early G1 phase of the cell cycle. In his Perspective, La Thangue discusses new findings (Ogawa et al.) that reveal the importance of an E2F family member, E2F-6, for silencing genes in quiescent cells in G0 of the cell cycle.

Nicholas B. La Thangue (University of Glasgow; Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences)

2002-05-10

187

DNA-Binding and TransActivation Properties of Drosophila E2F and DP Proteins  

Microsoft Academic Search

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

Brian David Dynlacht; Adam Brook; Marlene Dembski; Lynne Yenush; Nicholas Dyson

1994-01-01

188

Loss of E2F-1 reduces tumorigenesis and extends the lifespan of Rb1(+\\/-)mice  

Microsoft Academic Search

Mutation of the retinoblastoma tumour-suppressor gene (RB) leads to the deregulation of many proteins and transcription factors that interact with the retinoblastoma gene product (pRB), including members of the E2F transcription factor family. As pRB is known to repress E2F transcriptional activity and overexpression of E2F is sufficient for cell cycle progression, it is thought that pRB suppresses growth in

Lili Yamasaki; Roderick Bronson; Bart O. Williams; Nicholas J. Dyson; Ed Harlow; Tyler Jacks

1998-01-01

189

A revised picture of the E2F transcriptional network and RB function  

Microsoft Academic Search

New techniques have enhanced our picture of E2F regulation. These studies have shed light on the roles played by individual E2F and retinoblastoma family members and implicate these proteins in processes extending well beyond the G1\\/S transition. One thorny issue remains: do our current molecular models of E2F and retinoblastoma action explain all of the functions of these proteins in

Olivier Stevaux; Nicholas J Dyson

2002-01-01

190

Distinct and redundant functions of cyclin E1 and cyclin E2 in development and cancer  

Microsoft Academic Search

The highly conserved E-type cyclins are core components of the cell cycle machinery, facilitating the transition into S phase through activation of the cyclin dependent kinases, and assembly of pre-replication complexes on DNA. Cyclin E1 and cyclin E2 are assumed to be functionally redundant, as cyclin E1-\\/- E2-\\/- mice are embryonic lethal while cyclin E1-\\/- and E2-\\/- single knockout mice

C ELIZABETH Caldon; Elizabeth A Musgrove

2010-01-01

191

Stimulation of mucus and nonparietal cell secretion by the E 2 prostaglandins  

Microsoft Academic Search

The effects of prostaglandin E2 (PGE2), 15-methyl prostaglandin E2 (15M), and 16,16-dimethyl prostaglandin E2 (16DM) on gastric mucus and nonparietal cell secretion in rats were measured. Alcian blue binding was used as a measure of gastric mucus. Applied topically, all three agents stimulated nonparietal cell secretion, and PGE2 and 16 DM stimulated the secretion of mucus, increasing the fraction in

John P. Bolton; Douglas Palmer; Max M. Cohen

1978-01-01

192

Direct coupling of the cell cycle and cell death machinery by E2F  

Microsoft Academic Search

Unrestrained E2F activity forces S phase entry and promotes apoptosis through p53-dependent and -independent mechanisms. Here, we show that deregulation of E2F by adenovirus E1A, loss of Rb or enforced E2F-1 expression results in the accumulation of caspase proenzymes through a direct transcriptional mechanism. Increased caspase levels seem to potentiate cell death in the presence of p53-generated signals that trigger

Zaher Nahle; Julia Polakoff; Ramana V. Davuluri; Mila E. McCurrach; Matthew D. Jacobson; Masashi Narita; Michael Q. Zhang; Yuri Lazebnik; Dafna Bar-Sagi; Scott W. Lowe

2002-01-01

193

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

194

HPV16 E2 protein promotes innate immunity by modulating immunosuppressive status.  

PubMed

The balance between active immune responses against human papillomavirus (HPV) and HPV-induced immune escape regulates viral clearance and carcinogenesis. To understand the role of the early viral protein HPV16 E2 in host innate immune responses, the HPV16 E2-transfected murine squamous cell carcinoma cell line SCCVII (SCC/E2) was generated and anti-tumor responses in T-cell-depleted mice were evaluated. Tumor growth of SCC/E2 was markedly reduced. Cytotoxicity against the NK-sensitive targets YAC-1 and SCCVII was clearly enhanced in SCC/E2-inoculated mice. Despite the comparable ratio of NK cells, the proportion of CD11b(+)Gr-1(+) myeloid-derived suppressor cells (MDSCs) was significantly decreased in SCC/E2-inoculated mice. The transcription of MDSC-related mediators such as inducible nitric oxide synthase, indoleamine 2,3-dioxygenase, and heme oxygenase-1 was significantly impaired in the SCC/E2-inoculated tumor tissues on day 3. Our results suggest that HPV16 E2 promotes anti-tumor innate effector function by modulating immunoregulatory events mediated by MDSCs and their mediators. This report describes a new role for HPV16 E2 as a local immunomodulator at infected sites. PMID:24657154

Sunthamala, Nuchsupha; Pientong, Chamsai; Ohno, Tatsukuni; Zhang, Chenyang; Bhingare, Arundhati; Kondo, Yuta; Azuma, Miyuki; Ekalaksananan, Tipaya

2014-04-18

195

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

196

Downregulation of E2F1 during ER stress is required to induce apoptosis.  

PubMed

The endoplasmic reticulum (ER) has recently emerged as an alternative target to induce cell death in tumours, because prolonged ER stress results in the induction of apoptosis even in chemoresistant transformed cells. Here, we show that the DNA-damage-responsive pro-apoptotic factor E2F1 is unexpectedly downregulated during the ER stress-mediated apoptotic programme. E2F1 decline is a late event during the ER response and is mediated by the two unfolded protein response (UPR) sensors ATF6 and IRE1 (also known as ERN1). Whereas ATF6 directly interacts with the E2F1 promoter, IRE1 requires the involvement of the known E2F1 modulator E2F7, through the activation of its main target Xbp-1. Importantly, inhibition of the E2F1 decrease prevents ER-stress-induced apoptosis, whereas E2F1 knockdown efficiently sensitises cells to ER stress-dependent apoptosis, leading to the upregulation of two main factors in the UPR pro-apoptotic execution phase, Puma and Noxa (also known as BBC3 and PMAIP1, respectively). Our results point to a novel key role of E2F1 in the cell survival/death decision under ER stress, and unveil E2F1 inactivation as a valuable novel potential therapeutic strategy to increase the response of tumour cells to ER stress-based anticancer treatments. PMID:25616897

Pagliarini, Vittoria; Giglio, Paola; Bernardoni, Paolo; De Zio, Daniela; Fimia, Gian Maria; Piacentini, Mauro; Corazzari, Marco

2015-03-15

197

Characterization of the nuclear localization signal of high risk HPV16 E2 protein  

SciTech Connect

The E2 protein of high risk human papillomavirus type 16 (HPV16) contains an amino-terminal (N) domain, a hinge (H) region and a carboxyl-terminal (C) DNA-binding domain. Using enhanced green fluorescent protein (EGFP) fusions with full length E2 and E2 domains in transfection assays in HeLa cells, we found that the C domain is responsible for the nuclear localization of E2 in vivo, whereas the N and H domains do not contain additional nuclear localization signals (NLSs). Deletion analysis of EGFP-E2 and EGFP-cE2 determined that the C domain contains an {alpha} helix cNLS that overlaps with the DNA-binding region. Mutational analysis revealed that the arginine and lysine residues in this cNLS are essential for nuclear localization of HPV16 E2. Interestingly, these basic amino acid residues are well conserved among the E2 proteins of BPV-1 and some high risk HPV types but not in the low risk HPV types, suggesting that there are differences between the NLSs and corresponding nuclear import pathways between these E2 proteins.

Klucevsek, Kristin [Biology Department, Boston College, Higgins Hall, room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Wertz, Mary [Biology Department, Boston College, Higgins Hall, room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Lucchi, John [Biology Department, Boston College, Higgins Hall, room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Leszczynski, Anna [Biology Department, Boston College, Higgins Hall, room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Moroianu, Junona [Biology Department, Boston College, Higgins Hall, room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States)]. E-mail: moroianu@bc.edu

2007-03-30

198

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

199

Improving the performance of membrane bioreactors by powdered activated carbon dosing with cost considerations.  

PubMed

Effects of powdered activated carbon (PAC) dosing on the overall performance of membrane bioreactors (MBR) were investigated in two bench-scale submerged MBRs. Positive impacts of PAC dosing on membrane fouling and the removal of 17beta-estradiol (E2) and 17alpha-ethyinylestradiol (EE2) were demonstrated over a six-month stable operational period. PAC dosing in the MBR increased the removal rates of E2 and EE2 by 3.4% and 15.8%, respectively. The average soluble extracellular polymeric substances (EPS) and colloidal total organic carbon (TOC) concentrations in the PAC-MBR sludge was 60.1% and 61.8% lower than the control MBR sludge, respectively. Lower soluble EPS and colloidal TOC concentrations in the PAC-MBR sludge resulted in a slower rate of trans-membrane pressure (TMP) increase during MBRs operation, which could prolong the lifespan of membranes. Cost assessment showed that PAC dosing could reduce the operating cost for membrane cleaning and/or membrane replacement by about 25%. The operating cost for PAC dosing could be offset by the benefit from its reducing the cost for membrane maintenance. PMID:20595768

Yang, W; Paetkau, M; Cicek, N

2010-01-01

200

Phenotypic anchoring of gene expression changes during estrogen-induced uterine growth.  

PubMed

A major challenge in the emerging field of toxicogenomics is to define the relationships between chemically induced changes in gene expression and alterations in conventional toxicologic parameters such as clinical chemistry and histopathology. We have explored these relationships in detail using the rodent uterotrophic assay as a model system. Gene expression levels, uterine weights, and histologic parameters were analyzed 1, 2, 4, 8, 24, 48, and 72 hr after exposure to the reference physiologic estrogen 17 beta-estradiol (E2). A multistep analysis method, involving unsupervised hierarchical clustering followed by supervised gene ontology-driven clustering, was used to define the transcriptional program associated with E2-induced uterine growth and to identify groups of genes that may drive specific histologic changes in the uterus. This revealed that uterine growth and maturation are preceded and accompanied by a complex, multistage molecular program. The program begins with the induction of genes involved in transcriptional regulation and signal transduction and is followed, sequentially, by the regulation of genes involved in protein biosynthesis, cell proliferation, and epithelial cell differentiation. Furthermore, we have identified genes with common molecular functions that may drive fluid uptake, coordinated cell division, and remodeling of luminal epithelial cells. These data define the mechanism by which an estrogen induces organ growth and tissue maturation, and demonstrate that comparison of temporal changes in gene expression and conventional toxicology end points can facilitate the phenotypic anchoring of toxicogenomic data. PMID:15598610

Moggs, Jonathan G; Tinwell, Helen; Spurway, Tracey; Chang, Hur-Song; Pate, Ian; Lim, Fei Ling; Moore, David J; Soames, Anthony; Stuckey, Ruth; Currie, Richard; Zhu, Tong; Kimber, Ian; Ashby, John; Orphanides, George

2004-11-01

201

Estrogenic activity of phthalate esters by in vitro VTG assay using primary-cultured Xenopus hepatocytes.  

PubMed

Estrogenic activity of phthalate esters in dental soft resins was evaluated with an amphibian system consisting of a vitellogenin (VTG)-detecting Enzyme-Linked Immunosorbent Assay and a primary-cultured hepatocyte assay using adult male Xenopus laevis. In particular, phthalate esters--Di-n-butyl phthalate (DBP), Butyl phthalyl butyl glycolate (BPBG), Benzyl butyl phthalate (BBP), and Benzyl benzoate (BB)--were investigated. Bisphenol A (BPA) was prepared for comparison with these chemicals, and 17beta-estradiol (E2) was used as a positive control. The chemicals were diluted in dimethyl sulfoxide (DMSO) to obtain final concentrations ranging from 10(-11) to 10(-4) mol/l. BPA induced estrogenic activity at a concentration of 1.1x10(-6) mol/l, while E2 showed at 4.1x10(-11) mol/l. DBP, BBP, BB, and BPBG showed no estrogenic activity at concentrations between 4x10(-7) mol/l and 1x10(-4) mol/l. The latter result indicated that these phthalate esters might be metabolically transformed into non-estrogenic substances in Xenopus hepatocytes. Furthermore, this study demonstrated that through in vitro metabolism assessment, the estrogenic activity of chemical substances could be directly detected in terms of VTG secretion in primary-cultured Xenopus hepatocytes. PMID:17076324

Nomura, Yuji; Mitsui, Naoko; Bhawal, Ujjal Kumar; Sawajiri, Masahiko; Tooi, Osamu; Takahashi, Toru; Okazaki, Masayuki

2006-09-01

202

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

203

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

204

The use of modelling to predict levels of estrogens in a river catchment: how does modelled data compare with chemical analysis and in vitro yeast assay results?  

PubMed

Effluent discharges at Rodbourne sewage treatment works (STWs) were assessed using chemical and in vitro biological analysis as well as modelling predictions. Results showed that Rodbourne STW discharged less estrone (E1) than expected, but similar 17beta-estradiol (E2) and 17alpha-ethinyl estradiol (EE2) to those predicted by a widely cited effluent prediction model. The Exposure Analysis Modelling System (EXAMS) model was set up using measured effluent concentrations as its starting point to predict estrogen concentrations along a 10 km length of the receiving water of the River Ray. The model adequately simulated estrogen concentrations along the river when compared to July 2007 measured data. The model predicted combined estrogen equivalents in reasonable agreement with estrogenicity as measured by passive sampler (POCIS) extracts using the yeast estrogen screen. Using gauged mean flow values for 2007 the model indicated that the most important determinand for estrogen exposure in the Ray was not season, but proximity to the Rodbourne effluent. Thus, fish in the first 3 km downstream of Rodbourne were typically exposed to two or even three times more estrogens than those living 7-10 km further downstream. The modelling indicated that, assuming the effluent estrogen concentrations measured in February 2008 were typical, throughout the year the whole length of the Ray downstream of Rodbourne would be estrogenic, i.e. exceeding the 1 ng/L E2 equivalent threshold for endocrine disruption. PMID:20673965

Balaam, Jan L; Grover, Darren; Johnson, Andrew C; Jürgens, Monika; Readman, James; Smith, Andy J; White, Stefan; Williams, Richard; Zhou, John L

2010-09-15

205

Bio-analytical and chemical characterisation of offshore produced water effluents for estrogen receptor (ER) agonists.  

PubMed

The in vitro estrogen receptor (ER) agonist potency and C1 to C9 alkyl substituted phenol content of offshore produced water effluents collected from the UK sector of the North Sea were determined using a combination of bio-analytical and chemical analysis techniques. An in vitro reporter gene assay was used to determine ER agonist potency, whilst gas chromatography coupled to mass spectrometry (GC-MS) was used to quantify the concentration of alkylphenols. The in vitro ER agonist potency was highly variable and ranged from less than the limit of detection (theoretically 0.03 ng 17beta-estradiol (E2) l(-1)) to 91 ng E2 l(-1). C1 to C5 alkylphenol concentrations were also highly variable ranging from 5 to 1600 microg l(-1) with a median concentration of 206 microg l(-1). These data reflect the highly variable composition of produced water discharges from different fields. The observed poor correlation of the alkylphenol isomer content and ER agonist activity suggests that other compounds present in the produced water discharges may be responsible for the ER agonist activity observed. It is recommended that further work be performed to characterise the full range of ER agonists present in offshore produced water discharges. PMID:15237289

Thomas, Kevin V; Balaam, Jan; Hurst, Mark R; Thain, John E

2004-07-01

206

Effects of atrazine on hepatic metabolism and endocrine homeostasis in rainbow trout (Oncorhynchus mykiss)  

SciTech Connect

The herbicide atrazine (ATZ) is one of the most widely used pesticides in the world and is now under scrutiny for its alleged capacity to disrupt the endocrine system. Exhibiting negligible interaction with the estrogen receptor (ER), ATZ's mode of action remains to be elucidated. ATZ may act as an inducer of the enzyme aromatase, which converts androgens to estrogens, although other mechanisms should also be taken into consideration such as impairment of hepatic metabolism. Therefore we administered juvenile rainbow trout (Oncorhynchus mykiss) a dose of either 2 or 200 {mu}g ATZ/kg, or of carrier control phosphate buffered saline (PBS) and we measured plasma concentrations of testosterone (T), 17beta-estradiol (E2) and vitellogenin (Vtg) 6 days after exposure. Simultaneously we analyzed hepatic gene expression of cytochrome P450 (CYP) 1A and pi-class glutathione S-transferase (GST-P), and catalase (CAT) activity. Although sex steroid levels showed no significant alterations, we found a dose-dependent increase in Vtg and a concomitant decrease in CYP1A. There was no effect of ATZ on GST-P mRNA levels but GST-P was positively correlated with CYP1A. Also, CYP1A was negatively correlated with liver CAT and E2, and varied with T concentrations in a hormetic manner. The results showed that ATZ can alter hepatic metabolism, induce estrogenic effects and oxidative stress in vivo, and that these effects are linked.

Salaberria, Iurgi [Department of Zoology and Animal Cell Biology, University of the Basque Country, Apdo. 644, E-48080 Bilbao (Spain); Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)], E-mail: iurgi.salaberria@hotmail.com; Hansen, Bjorn Henrik [SINTEF Materials and Chemistry, Marine Environmental Technology, N-7465 Trondheim (Norway); Asensio, Vega [Department of Zoology and Animal Cell Biology, University of the Basque Country, Apdo. 644, E-48080 Bilbao (Spain); Olsvik, Pal A. [National Institute of Nutrition and Seafood Research (NIFES), Nordnes, N-5817 Bergen (Norway); Andersen, Rolf A.; Jenssen, Bjorn Munro [Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

2009-01-01

207

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

208

Adsorption of estrogens on laboratory materials and filters during sample preparation.  

PubMed

Despite improvements in analytical techniques for detecting hormones, such as estrogen in environmental samples, there is conflicting information regarding sample filtration before analyses. In addition, there is little information about estrogen adsorption onto other common laboratory materials, including glass, plastic, or stainless steel. Therefore, we have quantified the adsorption of three different types of estrogen (estrone [E1], 17alpha-ethynylestradiol [EE2], and 17beta-estradiol [E2]) onto 11 different types of filters and six other types of materials used for sample storage and laboratory experiments. We observed significant (p < 0.05) differences in the amount of estrogen adsorbed to the different filters. Glass fiber filters adsorbed the lowest amount, whereas nylon filters adsorbed nearly all of the estrogen that contacted them during filtration. Stainless steel and polycarbonate also adsorbed significant amounts of E1, E2, and EE2. The materials with which estrogen comes into contact should be chosen carefully to avoid potential losses due to sorption. PMID:20176847

Walker, Charles W; Watson, John E

2010-01-01

209

Effects of bisphenol A given neonatally on reproductive functions of male rats.  

PubMed

Male Sprague-Dawley rats (Crj:CD (IGS) were treated neonatally with bisphenol A (BPA) to evaluate effects on reproductive parameters. Animals were given BPA subcutaneously in corn oil to dosages of 0.002-97 mg/kg body weight, or 0.9 mg/kg 17beta-estradiol (E2) once a day from postnatal day (PND) 0 to PND 9. Preputial separation, copulatory rate, fertility rate, sperm analysis, serum testosterone levels, and gene expression in the testis were assessed. Males in the E2 group showed a decrease in testis weight and alterations of estrogen-mediated gene expression in the testis on PND 10, and by PND 150 incomplete preputial separation, decreases in the copulatory rate, testicular and accessory organ weights and number of sperm. In contrast, males in all BPA groups showed normal reproductive parameters. These results indicate that in male rats, BPA given during the neonatal period neither affected reproductive function nor evoked estrogen-mediated gene responses in the testis. PMID:16311018

Kato, Hideo; Furuhashi, Tadakazu; Tanaka, Masami; Katsu, Yoshinao; Watanabe, Hajime; Ohta, Yasuhiko; Iguchi, Taisen

2006-07-01

210

Augmentation of estrogen receptor-mediated transcription by steroid and xenobiotic receptor.  

PubMed

The estrogen receptor (ER) is a key regulator of proliferation and differentiation in breast cancer cells. In the present study, the effect of steroid and xenobiotic receptor (SXR) on 17/beta-estradiol (E2)-induced transcription through ERalpha was studied. SXR augmented ER-mediated transcription in the presence of E2 in MCF-7 breast cancer-derived cells and CV-1 fibroblast-derived cells. On the other hand, SXR alone did not affect the estrogen response element (ERE)-containing promoter activity in CV-1 cells. SXR did not directly bind to ERalpha or ERE in vitro, indicating that SXR may affect ER-mediated transcription by altering cofactor binding to ER. Although SXR did not alter the binding between ERalpha and p300/CBP interacting protein (p/CIP), it decreased the binding of a specific corepressor, silencing mediator of retinoid and thyroid hormone receptors (SMRT) to liganded ERalpha as assessed by mammalian two-hybrid, glutathione S-transferase pull-down, immunoprecipitation and newly developed Liquid Chemiluminescent DNA Pull-Down Assays. These results indicate that SXR augmented ER-mediated transcription by dissociating SMRT from ERalpha. Thus, the expression of SXR in breast cancer cells may alter the ER signaling, which may play crucial role for growth and differentiation of breast cancer cells. PMID:19011999

Rokutanda, Nana; Iwasaki, Toshiharu; Odawara, Hiroki; Nagaoka, Rin; Miyazaki, Wataru; Takeshita, Akira; Koibuchi, Yukio; Horiguchi, Jun; Shimokawa, Noriaki; Iino, Yuichi; Morishita, Yasuo; Koibuchi, Noriyuki

2008-06-01

211

Criteria for the establishment of a double-labeling assay for simultaneous determination of estrogen and progesterone receptors.  

PubMed

The availability of [125I]-16 alpha-iodo-3,17 beta-estradiol ( [125I]-E2) with binding characteristics similar to estrogen receptor (ER) enabled us to establish a double-labeling assay for the simultaneous determination of ER and progesterone receptors (PgR) using 125I-E2 and [3H]-R5020. The criteria for the establishment of such a double-labeling assay are described. 150 human mammary tumor cytosols have been investigated with the standard routine receptor assay for ER as well as PgR and the results were compared to those obtained by the double-labeling assay. ER: a coefficient of correlation of 0.691 was obtained, the parameters of the regression line were Y = 1.025 X X-0.036. When referring to the standard assay, 3 determinations were false-positive and 4 false-negative. PgR: a correlation coefficient of 0.984 was found, the parameters of the regression line were Y = 0.960 X X + 12.16. One value was false-negative and 1 false-positive. An equivalence of the two methods could be demonstrated. This new assay reduces by half the amount of tissue necessary for a valid 4- to 6-point saturation analysis, the time required for performing the assay and its cost. PMID:6538328

Grill, H J; Manz, B; Belovsky, O; Pollow, K

1984-01-01

212

Estrogenic chemicals and estrogenicity in river waters of South Korea and seven Asian countries.  

PubMed

The effects of treatment processes on estrogenicity were evaluated by examining estradiol equivalent (EEQ) concentrations in influents and effluents of sewage treatment plants (STPs) located along Yeongsan and Seomjin rivers in Korea. The occurrence and distribution of estrogenic chemicals were also estimated for surface water in Korea and compared with seven other Asian countries including Laos, Cambodia, Vietnam, China, Indonesia, Thailand and Malaysia. Target compounds were nonylphenol (NP), octylphenol (OP), bisphenol A (BPA), estrone (E1), 17beta-estradiol (E2), 17alpha-ethynylestradiol (EE2) and genistein (Gen). Water samples were pretreated and analyzed by liquid-liquid extraction (LLE) and gas chromatography/mass spectrometry (GC/MS). The results showed that the treatment processes of Korean STPs were sufficient to reduce the estrogenic activity of municipal wastewater. The concentrations of phenolic xenoestrogens (i.e., NP, OP and BPA) in samples of Yeongsan and Seomjin rivers were smaller than those reported by previous studies in Korea. In most samples taken from the seven Asian countries, the presence of E2 and EE2 was a major contributor toward estrogenic activity. The EEQ concentrations in surface water samples of the seven Asian countries were at a higher level in comparison to that reported in European countries, America and Japan. However, further studies with more sampling frequencies and sampling areas should be carried out for better evaluation of the occurrence and distribution of estrogenic compounds in these Asian countries. PMID:19931116

Duong, Cuong N; Ra, Jin Sung; Cho, Jaeweon; Kim, Sang D; Choi, Hoon K; Park, Ji-Hyung; Kim, Kyoung W; Inam, Edu; Kim, Sang Don

2010-01-01

213

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

214

G protein-coupled receptor 30 is an estrogen receptor in the plasma membrane  

SciTech Connect

Recently, GPR30 was reported to be a novel estrogen receptor; however, its intracellular localization has remained controversial. To investigate the intracellular localization of GPR30 in vivo, we produced four kinds of polyclonal antibodies for distinct epitopes on GPR30. Immunocytochemical observations using anti-GPR30 antibody and anti-FLAG antibody show that FLAG-GPR30 localizes to the plasma membrane 24 h after transfection. Treatment with estrogen (17{beta}-estradiol or E2) causes an elevation in the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) within 10 s in HeLa cells expressing FLAG-GPR30. In addition, E2 induces the translocation of GPR30 from the plasma membrane to the cytoplasm by 1 h after stimulation. Immunohistochemical analysis shows that GPR30 exists on the cell surface of CA2 pyramidal neuronal cells. The images on transmission electron microscopy show that GPR30 is localized to a particular region associated with the plasma membranes of the pyramidal cells. These data indicate that GPR30, a transmembrane receptor for estrogen, is localized to the plasma membrane of CA2 pyramidal neuronal cells of the hippocampus in rat brain.

Funakoshi, Takeshi [Center for Gene Research, Yamaguchi University, Yamaguchi 755-8505 (Japan); Department of Bio-Signal Analysis, AMES, Graduate School of Medicine, Yamaguchi University, Yamaguchi 755-8505 (Japan); Yanai, Akie [Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University School of Medicine, Yamaguchi 755-8505 (Japan); Shinoda, Koh [Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University School of Medicine, Yamaguchi 755-8505 (Japan); Kawano, Michio M. [Department of Bio-Signal Analysis, AMES, Graduate School of Medicine, Yamaguchi University, Yamaguchi 755-8505 (Japan); Mizukami, Yoichi [Center for Gene Research, Yamaguchi University, Yamaguchi 755-8505 (Japan)]. E-mail: mizukami@yamaguchi-u.ac.jp

2006-08-04

215

Functional characterization of the Sindbis virus E2 glycoprotein by transposon linker-insertion mutagenesis  

SciTech Connect

The glycoprotein envelope of alphaviruses consists of two proteins, E1 and E2. E1 is responsible for fusion and E2 is responsible for receptor binding. An atomic structure is available for E1, but one for E2 has not been reported. In this study, transposon linker-insertion mutagenesis was used to probe the function of different domains of E2. A library of mutants, containing 19 amino acid insertions in the E2 glycoprotein sequence of the prototype alphavirus, Sindbis virus (SINV), was generated. Fifty-seven independent E2 insertions were characterized, of which more than half (67%) gave rise to viable virus. The wild-type-like mutants identify regions that accommodate insertions without perturbing virus production and can be used to insert targeting moieties to direct SINV to specific receptors. The defective and lethal mutants give insight into regions of E2 important for protein stability, transport to the cell membrane, E1-E2 contacts, and receptor binding.

Navaratnarajah, Chanakha K. [Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907-2054 (United States); Kuhn, Richard J. [Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907-2054 (United States)]. E-mail: kuhnr@purdue.edu

2007-06-20

216

Retinoblastoma protein (RB) interacts with E2F3 to control terminal differentiation of Sertoli cells.  

PubMed

The retinoblastoma protein (RB) is essential for normal cell cycle control. RB function depends, at least in part, on interactions with the E2F family of DNA-binding transcription factors (E2Fs). To study the role of RB in the adult testis, a Sertoli cell (SC)-specific Rb knockout mouse line (SC-RbKO) was generated using the Cre/loxP recombination system. SC-RbKO mice exhibited an age-dependent testicular atrophy, impaired fertility, severe SC dysfunction, and spermatogenic defects. Removal of Rb in SC induced aberrant SC cycling, dedifferentiation, and apoptosis. Here we show that E2F3 is the only E2F expressed in mouse SCs and that RB interacts with E2F3 during mouse testicular development. In the absence of RB, the other retinoblastoma family members p107 and p130 began interacting with E2F3 in the adult testes. In vivo silencing of E2F3 partially restored the SC maturation and survival as well as spermatogenesis in the SC-RbKO mice. These results point to RB as a key regulator of SC function in adult mice and that the RB/E2F3 pathway directs SC maturation, cell cycle quiescence, and RB protects SC from apoptosis. PMID:24901045

Rotgers, E; Rivero-Müller, A; Nurmio, M; Parvinen, M; Guillou, F; Huhtaniemi, I; Kotaja, N; Bourguiba-Hachemi, S; Toppari, J

2014-01-01

217

Cell cycle-related transformation of the E2F4-p130 repressor complex  

SciTech Connect

During G0 phase the p130, member of the pRb tumor suppressor protein family, forms a repressor complex with E2F4 which is inactivated in G1/S by hyperphosphorylation of the p130. The role of p130 after G1/S remains poorly investigated. We found that in nuclear extracts of T98G cells, the p130-E2F4-DNA (pp-E2F4) complex does not dissociate at G1/S transition, but instead reverts to the p130-E2F4-cyclin E/A-cdk2 (cyc/cdk-pp-E2F4) complex, which is detected in S and G2/M phases of the cell cycle. Hyperphosphorylation of the p130 at G1/S transition is associated with a decrease of its total amount; however, this protein is still detected during the rest of the cell cycle, and it is increasingly hyperphosphorylated in the cytosol, but continuously dephosphorylated in the nucleus. Both nuclear and cytosol cell fractions in T98G cells contain a hyperphosphorylated form of p130 in complex with E2F4 at S and G2/M cell cycle phases. In contrast to T98G cells, transformation of the p130 containing cyc/cdk-pp-E2F4 complex into the p130-pp-E2F4 repressor does not occur in HeLa cells under growth restriction conditions.

Popov, Boris [Institute of Cytology, Russian Academy of Sciences, 4, Tikhoretsky Ave., St. Petersburg 194064 (Russian Federation) and Department of Pediatrics, Children's Hospital, Ohio State University, Columbus, OH 43205-2696 (United States)]. E-mail: popov_478@hotmail.com; Chang, L.-S. [Department of Pediatrics, Children's Hospital, Ohio State University, Columbus, OH 43205-2696 (United States); Serikov, Vladimir [Institute of Cytology, Russian Academy of Sciences, 4, Tikhoretsky Ave., St. Petersburg 194064 (Russian Federation); Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609-1673 (United States)

2005-10-28

218

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

Code of Federal Regulations, 2011 CFR

...Testing Physical (Design) and Performance Characteristics of Reference Methods and Class I and Class II Equivalent Methods for PM2.5 or PM10â2.5 Pt. 53, Subpt. E, Fig. E-2 Figure E-2 to Subpart E of Part 53—Product Manufacturing...

2011-07-01

219

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

Code of Federal Regulations, 2012 CFR

...Testing Physical (Design) and Performance Characteristics of Reference Methods and Class I and Class II Equivalent Methods for PM2.5 or PM10â2.5 Pt. 53, Subpt. E, Fig. E-2 Figure E-2 to Subpart E of Part 53—Product Manufacturing...

2012-07-01

220

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

Code of Federal Regulations, 2010 CFR

...Testing Physical (Design) and Performance Characteristics of Reference Methods and Class I and Class II Equivalent Methods for PM2.5 or PM10â2.5 Pt. 53, Subpt. E, Fig. E-2 Figure E-2 to Subpart E of Part 53—Product Manufacturing...

2010-07-01

221

Resolvin E2 formation and impact in inflammation-resolution1  

PubMed Central

Acute inflammation and its resolution are essential processes for tissue protection and homeostasis. In this context, specialized pro-resolving mediators derived from polyunsaturated fatty acids are of interest. Here, we report that resolvin E2 (RvE2) from eicosapentaenoic acid is endogenously produced during self-limited murine peritonitis in both the initiation and resolution phases. RvE2 (1–10 nM) carries potent leukocyte-directed actions that include 1) regulating chemotaxis of human neutrophils, and 2) enhancing phagocytosis and anti-inflammatory cytokine production. These actions appear to be mediated by leukocyte G-protein coupled receptors as preparation of labeled RvE2 gave direct evidence for specific binding of radiolabeled RvE2 to neutrophils (Kd 24.7 ± 10.1 nM) and RvE1 activation of recombinant GPCRs was assessed. In addition to the murine inflammatory milieu, RvE2 was also identified in plasma from healthy human subjects. RvE2 rapidly downregulated surface expression of human leukocyte integrins in whole blood and dampened responses to platelet-activating factor. Together, these results indicate that RvE2 can stimulate host-protective actions throughout initiation and resolution in the innate inflammatory responses. PMID:22450811

Oh, Sungwhan F.; Dona, Maria; Fredman, Gabrielle; Krishnamoorthy, Sriram; Irimia, Daniel; Serhan, Charles N.

2012-01-01

222

Three-dimensional Reconstruction of Agrobacterium VirE2 Protein with Single-stranded DNA*  

E-print Network

Three-dimensional Reconstruction of Agrobacterium VirE2 Protein with Single-stranded DNA* Received-stranded DNA substrate is trans- ported across the two cell walls along with the bacterial virulence proteins VirD2 and VirE2. A single VirD2 mol- ecule covalently binds to the 5 -end of the single- stranded DNA

Citovsky, Vitaly

223

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

224

Regulation of the Arf tumor suppressor by E2F transcription factors  

E-print Network

Effective tumor suppression requires the appropriate function of two major signaling pathways, the pRB-E2F growth-control pathway and the p53 stress-response pathway. Members of the E2F family of transcription factors are ...

Iaquinta, Phillip John

2007-01-01

225

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

226

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

227

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

228

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

229

Prostaglandin E2 Stimulates Amyloid Precursor Protein Gene Expression: Inhibition by Immunosuppressants  

E-print Network

Prostaglandin E2 Stimulates Amyloid Precursor Protein Gene Expression: Inhibition dysfunction in transgenic mice. We now report that activation of prostaglandin E2 (PGE2 ) receptors increases. These results suggest that prostaglandins pro- duced by brain injury or inflammation can activate APP tran

Wurtman, Richard

230

Overexpression of E2F3 promotes proliferation of functional human ? cells without induction of apoptosis.  

PubMed

The mechanisms that control proliferation, or lack thereof, in adult human ? cells are poorly understood. Controlled induction of proliferation could dramatically expand the clinical application of islet cell transplantation and represents an important component of regenerative approaches to a functional cure of diabetes. Adult human ? cells are particularly resistant to common proliferative targets and often dedifferentiate during proliferation. Here we show that expression of the transcription factor E2F3 has a role in regulating ?-cell quiescence and proliferation. We found human islets have virtually no expression of the pro-proliferative G 1/S transcription factors E2F1-3, but an abundance of inhibitory E2Fs 4-6. In proliferative human insulinomas, inhibitory E2Fs were absent, while E2F3 is expressed. Using this pattern as a "roadmap" for proliferation, we demonstrated that ectopic expression of nuclear E2F3 induced significant expansion of insulin-positive cells in both rat and human islets. These cells did not undergo apoptosis and retained their glucose-responsive insulin secretion, showing the ability to reverse diabetes in mice. Our results suggest that E2F4-6 may help maintain quiescence in human ? cells and identify E2F3 as a novel target to induce proliferation of functional ? cells. Refinement of this approach may increase the islets available for cell-based therapies and research and could provide important cues for understanding in vivo proliferation of ? cells. PMID:23907129

Rady, Brian; Chen, Yanmei; Vaca, Pilar; Wang, Qian; Wang, Yong; Salmon, Patrick; Oberholzer, José

2013-08-15

231

Localization of E2A mRNA expression in developing and adult rat tissues.  

PubMed Central

E2A helix-loop-helix proteins are involved in the control of various developmental pathways. We show here by in situ hybridization that E2A transcripts are present in most embryonic and adult tissues. However, no E2A expression is detectable in heart and nonproliferative regions of the brain and spinal cord. Highest levels of E2A expression are found in the ependyma cell layer surrounding the cerebral ventricles in the embryonic rat brain. In addition, in the embryo, E2A transcripts were found in secretory cells of the pancreas, the bronchial tubes of the lung, glomeruli of the kidney, and the lining of the stomach. Interestingly, high levels of E2A transcripts are selectively found in the germinal center of the lymphatic nodules in the adult rat spleen. Thus, E2A, like its Drosophila homolog daughterless, is expressed in most tissues. The most notable feature of the E2A expression pattern is its high levels of expression in some areas of rapid cell proliferation and differentiation and in certain epithelial cell types. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8356060

Roberts, V J; Steenbergen, R; Murre, C

1993-01-01

232

Transplantation of bovine mammary tissue to athymic nude mice: growth subcutaneously and in mammary gland-free fat pads.  

PubMed

Mammary epithelium from five Holstein cows was transplanted as subcutaneous slices and as collagenase dissociated epithelial cells into mammary gland free-fat pads of athymic nude mice. Two weeks posttransplantation, mice were injected daily for 20 d with saline, 17 beta-estradiol plus progesterone, or 17 beta-estradiol plus progesterone plus growth hormone plus prolactin. In a second experiment, mice were treated with saline, cholera toxin, 17 beta-estradiol (subcutaneous pellet of 2 mg 17 beta-estradiol and 38 mg cholesterol), or 17 beta-estradiol plus cholera toxin. In each experiment mammary slices maintained normal morphology. Growth of epithelium within slices ([3H]thymidine autoradiography) was increased 167% by estradiol plus progesterone, 264% by estradiol plus progesterone plus growth hormone plus prolactin, 90% by estradiol, 60% by cholera toxin, and 137% by estradiol plus cholera toxin. Cells injected into mammary gland free fat pads formed hollow, multilayered, spherical "organoids." Organoid area was increased 47% by estradiol plus progesterone, 189% by estradiol plus progesterone plus growth hormone plus prolactin, 72% by estradiol, 86% by cholera toxin and 74% by estradiol plus cholera toxin. Thus, athymic nude mice appear suitable for the ex vivo in vivo study of bovine mammary epithelial growth and differentiation. PMID:3722534

Sheffield, L G; Welsch, C W

1986-04-01

233

Endometrium estradiol receptors type I and type II during early pregnancy of rat.  

PubMed

By centrifugation in a sucrose density gradient we studied the citosol 17beta-estradiol binding sites of blastocyst receptive and non-receptive endometrial zones, as well as uterine horn endometrium whose ovary was extirpated three weeks before pregnancy. The cytosol was prelabelled with [3H]-17beta-estradiol 2 and 25 nM. In this work two incubation temperatures were studied. On the other hand, at 4 degrees C unoccupied receptors were identified as different from the classic receptor 8S type I. At the same time, we found that 25 degrees C is the optimal temperature for the assay of total receptors to achieve complete exchange of [3H]-17beta-estradiol by 17beta-estradiol in the binding sites. In these conditions, the major component was the 4S type II receptor, mainly in the endometrium from ovariectomized uteri. Furthermore, 17beta-estradiol content was determined in the total homogenized by radioimmunoassay and the results were: 1.42+/-0.16, 1.22+/-0.15 and 1.75+/-0.27 pmol/g wet tissue for receptive, non-receptive and ovariectomized uteri, respectively. PMID:16442567

Salazar, Edith L; Calzada, Leobardo

2006-05-15

234

Review of clinical experience with estradiol in combined oral contraceptives.  

PubMed

Previous attempts to replace ethinylestradiol (EE) with 17beta-estradiol (E2) in combined oral contraceptives (COCs) have proved unsatisfactory in terms of bleeding outcomes. A review of previous studies of E2-based COCs has shown that, despite good ovulation inhibition, bleeding irregularities affected up to 100% of women, often resulting in high rates of discontinuation (up to 42%). Suggested reasons for the bleeding irregularities observed with these predominantly monophasic estradiol-progestin preparations included suboptimal doses of E2 and an inappropriate estrogen/progestin ratio. The progestin used in the investigated formulations (e.g., norethisterone acetate, desogestrel and cyproterone acetate) may also have affected the overall bleeding profile. More recent studies of a multiphasic COC containing estradiol valerate (E2V) and dienogest (DNG) indicate efficient ovulation inhibition and acceptable cycle control. In a randomized, double-blind trial that compared E2V/DNG with a monophasic COC comprising EE/levonorgestrel (LNG), the occurrence of scheduled withdrawal bleeding per cycle with E2V/DNG and EE/LNG was 77.7-83.2% and 89.5-93.8%, respectively. The intensity and duration of withdrawal bleeding was reduced with E2V/DNG. The incidence of intracyclic bleeding was similar with E2V/DNG (10.5-18.6%) and EE/LNG (9.9-17.1%). This review shows that after several unsatisfactory attempts to develop E2-based COCs, more recent studies employing endometrial-focused progestins, e.g., DNG, and multiphasic dosing regimens appear to be a promising approach for an E2-based COC that provides efficient ovulation inhibition and acceptable cycle control. PMID:20004267

Fruzzetti, Franca; Bitzer, Johannes

2010-01-01

235

EKLF/KLF1 Controls Cell Cycle Entry via Direct Regulation of E2f2*  

PubMed Central

Differentiation of erythroid cells requires precise control over the cell cycle to regulate the balance between cell proliferation and differentiation. The zinc finger transcription factor, erythroid Krüppel-like factor (EKLF/KLF1), is essential for proper erythroid cell differentiation and regulates many erythroid genes. Here we show that loss of EKLF leads to aberrant entry into S-phase of the cell cycle during both primitive and definitive erythropoiesis. This cell cycle defect was associated with a significant reduction in the expression levels of E2f2 and E2f4, key factors necessary for the induction of S-phase gene expression and erythropoiesis. We found and validated novel intronic enhancers in both the E2f2 and E2f4 genes, which contain conserved CACC, GATA, and E-BOX elements. The E2f2 enhancer was occupied by EKLF in vivo. Furthermore, we were able to partially restore cell cycle dynamics in EKLF?/? fetal liver upon additional genetic depletion of Rb, establishing a genetic causal link between reduced E2f2 and the EKLF cell cycle defect. Finally, we propose direct regulation of the E2f2 enhancer is a generic mechanism by which many KLFs regulate proliferation and differentiation. PMID:19457859

Tallack, Michael R.; Keys, Janelle R.; Humbert, Patrick O.; Perkins, Andrew C.

2009-01-01

236

Hox and a Newly Identified E2F Co-repress Cell Death in Caenorhabditis elegans  

PubMed Central

The development of an organism depends on individual cells receiving and executing their specific fates, although how this process is regulated remains largely unknown. Here, we identify a mechanism by which a specific cell fate, apoptosis, is determined through the cooperative efforts of Hox and E2F proteins. E2F transcription factors are critical, conserved regulators of the cell cycle and apoptosis. However, little is known about the two most recently discovered mammalian E2Fs—E2F7 and E2F8. In the nematode Caenorhabditis elegans, we identify a novel E2F7/8 homolog, EFL-3, and show that EFL-3 functions cooperatively with LIN-39, providing the first example in which these two major developmental pathways—E2F and Hox—are able to directly regulate the same target gene. Our studies demonstrate that LIN-39 and EFL-3 function in a cell type-specific context to regulate transcription of the egl-1 BH3-only cell death gene and to determine cell fate during development. PMID:21596899

Winn, Jennifer; Carter, Monique; Avery, Leon; Cameron, Scott

2011-01-01

237

Oncogenic ETS fusions deregulate E2F3 target genes in Ewing sarcoma and prostate cancer  

PubMed Central

Deregulated E2F transcription factor activity occurs in the vast majority of human tumors and has been solidly implicated in disturbances of cell cycle control, proliferation, and apoptosis. Aberrant E2F regulatory activity is often caused by impairment of control through pRB function, but little is known about the interplay of other oncoproteins with E2F. Here we show that ETS transcription factor fusions resulting from disease driving rearrangements in Ewing sarcoma (ES) and prostate cancer (PC) are one such class of oncoproteins. We performed an integrative study of genome-wide DNA-binding and transcription data in EWSR1/FLI1 expressing ES and TMPRSS2/ERG containing PC cells. Supported by promoter activity and mutation analyses, we demonstrate that a large fraction of E2F3 target genes are synergistically coregulated by these aberrant ETS proteins. We propose that the oncogenic effect of ETS fusion oncoproteins is in part mediated by the disruptive effect of the E2F–ETS interaction on cell cycle control. Additionally, a detailed analysis of the regulatory targets of the characteristic EWSR1/FLI1 fusion in ES identifies two functionally distinct gene sets. While synergistic regulation in concert with E2F in the promoter of target genes has a generally activating effect, EWSR1/FLI1 binding independent of E2F3 is predominantly associated with repressed differentiation genes. Thus, EWSR1/FLI1 appears to promote oncogenesis by simultaneously promoting cell proliferation and perturbing differentiation. PMID:23940108

Bilke, Sven; Schwentner, Raphaela; Yang, Fan; Kauer, Maximilian; Jug, Gunhild; Walker, Robert L.; Davis, Sean; Zhu, Yuelin J.; Pineda, Marbin; Meltzer, Paul S.; Kovar, Heinrich

2013-01-01

238

Hox and a newly identified E2F co-repress cell death in Caenorhabditis elegans.  

PubMed

The development of an organism depends on individual cells receiving and executing their specific fates, although how this process is regulated remains largely unknown. Here, we identify a mechanism by which a specific cell fate, apoptosis, is determined through the cooperative efforts of Hox and E2F proteins. E2F transcription factors are critical, conserved regulators of the cell cycle and apoptosis. However, little is known about the two most recently discovered mammalian E2Fs-E2F7 and E2F8. In the nematode Caenorhabditis elegans, we identify a novel E2F7/8 homolog, EFL-3, and show that EFL-3 functions cooperatively with LIN-39, providing the first example in which these two major developmental pathways-E2F and Hox-are able to directly regulate the same target gene. Our studies demonstrate that LIN-39 and EFL-3 function in a cell type-specific context to regulate transcription of the egl-1 BH3-only cell death gene and to determine cell fate during development. PMID:21596899

Winn, Jennifer; Carter, Monique; Avery, Leon; Cameron, Scott

2011-08-01

239

E2F-7 couples DNA damage-dependent transcription with the DNA repair process  

PubMed Central

The cellular response to DNA damage, mediated by the DNA repair process, is essential in maintaining the integrity and stability of the genome. E2F-7 is an atypical member of the E2F family with a role in negatively regulating transcription and cell cycle progression under DNA damage. Surprisingly, we found that E2F-7 makes a transcription-independent contribution to the DNA repair process, which involves E2F-7 locating to and binding damaged DNA. Further, E2F-7 recruits CtBP and HDAC to the damaged DNA, altering the local chromatin environment of the DNA lesion. Importantly, the E2F-7 gene is a target for somatic mutation in human cancer and tumor-derived mutant alleles encode proteins with compromised transcription and DNA repair properties. Our results establish that E2F-7 participates in 2 closely linked processes, allowing it to directly couple the expression of genes involved in the DNA damage response with the DNA repair machinery, which has relevance in human malignancy. PMID:23974101

Zalmas, Lykourgos-Panagiotis; Coutts, Amanda S; Helleday, Thomas; La Thangue, Nicholas B

2013-01-01

240

OTUB1 co-opts Lys48-linked ubiquitin recognition to suppress E2 enzyme function  

PubMed Central

SUMMARY Ubiquitylation entails the concerted action of E1, E2 and E3 enzymes. We recently reported that OTUB1, a deubiquitylase, inhibits the DNA damage response independently of its isopeptidase activity. OTUB1 does so by blocking ubiquitin transfer by UBC13, the cognate E2 enzyme for RNF168. OTUB1 also inhibits E2s of the UBE2D and UBE2E families. Here we elucidate the structural mechanism by which OTUB1 binds E2s to inhibit ubiquitin transfer. OTUB1 recognizes ubiquitin-charged E2s through contacts with both donor ubiquitin and the E2 enzyme. Surprisingly, free ubiquitin associates with the canonical distal ubiquitin-binding site on OTUB1 to promote formation of the inhibited E2 complex. Lys48 of donor ubiquitin lies near the OTUB1 catalytic site and the C-terminus of free ubiquitin, a configuration that mimics the products of Lys48-linked ubiquitin chain cleavage. OTUB1 therefore co-opts Lys48-linked ubiquitin chain recognition to suppress ubiquitin conjugation and the DNA damage response. PMID:22325355

Juang, Yu-Chi; Landry, Marie-Claude; Sanches, Mario; Vittal, Vinayak; Leung, Charles; Ceccarelli, Derek F.; Mateo, Abigail-Rachele F.; Pruneda, Jonathan N.; Mao, Dan; Szilard, Rachel K.; Orlicky, Stephen; Munro, Meagan; Brzovic, Peter S.; Klevit, Rachel E.; Sicheri, Frank; Durocher, Daniel

2012-01-01

241

OTUB1 Co-opts Lys48-Linked Ubiquitin Recognition to Suppress E2 Enzyme Function  

SciTech Connect

Ubiquitylation entails the concerted action of E1, E2, and E3 enzymes. We recently reported that OTUB1, a deubiquitylase, inhibits the DNA damage response independently of its isopeptidase activity. OTUB1 does so by blocking ubiquitin transfer by UBC13, the cognate E2 enzyme for RNF168. OTUB1 also inhibits E2s of the UBE2D and UBE2E families. Here we elucidate the structural mechanism by which OTUB1 binds E2s to inhibit ubiquitin transfer. OTUB1 recognizes ubiquitin-charged E2s through contacts with both donor ubiquitin and the E2 enzyme. Surprisingly, free ubiquitin associates with the canonical distal ubiquitin-binding site on OTUB1 to promote formation of the inhibited E2 complex. Lys48 of donor ubiquitin lies near the OTUB1 catalytic site and the C terminus of free ubiquitin, a configuration that mimics the products of Lys48-linked ubiquitin chain cleavage. OTUB1 therefore co-opts Lys48-linked ubiquitin chain recognition to suppress ubiquitin conjugation and the DNA damage response.

Juang, Yu-Chi; Landry, Marie-Claude; Sanches, Mario; Vittal, Vinayak; Leung, Charles C.Y.; Ceccarelli, Derek F.; Mateo, Abigail-Rachele F.; Pruneda, Jonathan N.; Mao, Daniel Y.L.; Szilard, Rachel K.; Orlicky, Stephen; Munro, Meagan; Brzovic, Peter S.; Klevit, Rachel E.; Sicheri, Frank; Durocher, Daniel (Mount Sinai Hospital); (UWASH)

2012-03-26

242

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

243

Droloxifene does not blunt bone anabolic effects of prostaglandin E 2, but maintains prostaglandin E 2restored bone in aged, ovariectomized rats  

Microsoft Academic Search

Droloxifene (DRO) is a selective estrogen receptor modulator that prevents bone loss by inhibition of bone turnover associated with estrogen deficiency in both growing and aged female rats. The purposes of this study were to test: (a) whether DRO can maintain prostaglandin E2 (PGE2)-restored bone after discontinuation of PGE2 in aged, ovariectomized (ovx) rats; (b) if an inhibition of bone

H. Z Ke; D. T Crawford; H Qi; C. M Pirie; H. A Simmons; K. L Chidsey-Frink; H. K Chen; W. S. S Jee; D. D Thompson

1999-01-01

244

Rendezvous with Toutatis from the Moon: The Chang'e-2 mission  

NASA Astrophysics Data System (ADS)

Chang'e-2 probe was the second lunar probe of China, with the main objectives to demonstrate some key features of the new lunar soft landing technology, and its applications to future exploration missions. After completing the planned mission successfully, Chang'e-2 flew away from the Moon and entered into the interplanetary space. Later, at a distance of 7 million km from the Earth, Chang'e-2 encountered asteroid (4179) Toutatis with a very close fly-by distance and obtained colorful images with a 3-m resolution. Given some surplus velocity increment as well as the promotion of autonomous flight ability and improvement of control, propulsion, and thermal systems in the initial design, Chang'e-2 had the capabilities necessary for escaping from the Moon. By taking advantage of the unique features of the Lagrangian point, the first close fly-by of asteroid Toutatis was realized despite the tight constraints of propellant allocation, spacecraft-Earth communication, and coordination of execution sequences. Chang'e-2 realized the Toutatis flyby with a km-level distance at closest approach. In the absence of direct measurement method, based on the principle of relative navigation and through the use of the sequence of target images, we calculated the rendezvous parameters such as relative distance and image resolution. With the help of these parameters, some fine and new scientific discoveries about the asteroid were obtained by techniques of optical measurements and image processing. Starting with an innovative design, followed by high-fidelity testing and demonstration, elaborative implementation, and optimal usage of residual propellant, Chang'e-2 has for the first time successfully explored the Moon, L2 point and an asteroid, while achieving the purpose of 'faster, better, cheaper'. What Chang'e-2 has accomplished was far beyond our expectations. *J. Huang is the chief designer (PI) of Chang'e-2 probe, planned Chang'e-2's multi-objective and multitasking exploration mission.

Huang, J.; Tang, X.; Meng, L.

2014-07-01

245

A Conserved E2F6-Binding Element in Murine Meiosis-Specific Gene Promoters1  

PubMed Central

During gametogenesis, germ cells must undergo meiosis in order to become viable haploid gametes. Successful completion of this process is dependent upon the expression of genes whose protein products function specifically in meiosis. Failure to express these genes in meiotic cells often results in infertility, whereas aberrant expression in somatic cells may lead to mitotic catastrophe. The mechanisms responsible for regulating the timely expression of meiosis-specific genes have not been fully elucidated. Here we demonstrate that E2F6, a member of the E2F family of transcription factors, is essential for the repression of the newly identified meiosis-specific gene, Slc25a31 (also known as Ant4, Aac4), in somatic cells. This discovery, along with previous studies, prompted us to investigate the role of E2F6 in the regulation of meiosis-specific genes in general. Interestingly, the core E2F6-binding element (TCCCGC) was highly conserved in the proximal promoter regions of 19 out of 24 (79.2%) meiosis-specific genes. This was significantly higher than the frequency found in the promoters of all mouse genes (15.4%). In the absence of E2F6, only a portion of these meiosis-specific genes was derepressed in somatic cells. However, endogenous E2F6 bound to the promoters of these meiosis-specific genes regardless of whether they required E2F6 for their repression in somatic cells. Further, E2F6 overexpression was capable of reducing their transcription. These findings indicate that E2F6 possesses a broad ability to bind to and regulate the meiosis-specific gene population.. PMID:18667754

Kehoe, Sarah M.; Oka, Masahiro; Hankowski, Katherine E.; Reichert, Nina; Garcia, Sandra; McCarrey, John R.; Gaubatz, Stefan; Terada, Naohiro

2008-01-01

246

Erythropoiesis and globin gene expression in mice lacking the transcription factor NF-E2.  

PubMed Central

Previous studies in transgenic mice and cultured cells have indicated that the major enhancer function for erythroid cell expression of the globin genes is provided by the heterodimeric basic-leucine zipper transcription factor NF-E2. Globin gene expression within cultured mouse erythroleukemia cells is highly dependent on NF-E2. To examine the requirement for this factor in vivo, we used homologous recombination in embryonic stem cells to generate mice lacking the hematopoietic-specific subunit, p45 NF-E2. The most dramatic aspect of the homozygous mutant mice was an absence of circulating platelets, which led to the death of most animals due to hemorrhage. In contrast, the effect of loss of NF-E2 on the erythroid lineage was surprisingly mild. Although neonates exhibited severe anemia and dysmorphic red-cell changes, probably compounded by concomitant bleeding, surviving adults exhibited only mild changes consistent with a small decrease in the hemoglobin content per cell. p45 NF-E2-null mice responded to anemia with compensatory reticulocytosis and splenomegaly. Globin chain synthesis was balanced, and switching from fetal to adult globins progressed normally. Although these findings are consistent with the substitution of NF-E2 function in vivo by one or more compensating proteins, gel shift assays using nuclear extracts from p45 NF-E2-null mice failed to reveal novel complexes formed on an NF-E2 binding site. Thus, regulation of globin gene transcription through NF-E2 binding sites in vivo is more complex than has been previously appreciated. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7567998

Shivdasani, R A; Orkin, S H

1995-01-01

247

Analysis of the human E2 ubiquitin conjugating enzyme protein interaction network  

PubMed Central

In eukaryotic cells the stability and function of many proteins are regulated by the addition of ubiquitin or ubiquitin-like peptides. This process is dependent upon the sequential action of an E1-activating enzyme, an E2-conjugating enzyme, and an E3 ligase. Different combinations of these proteins confer substrate specificity and the form of protein modification. However, combinatorial preferences within ubiquitination networks remain unclear. In this study, yeast two-hybrid (Y2H) screens were combined with true homology modeling methods to generate a high-density map of human E2/E3-RING interactions. These data include 535 experimentally defined novel E2/E3-RING interactions and >1300 E2/E3-RING pairs with more favorable predicted free-energy values than the canonical UBE2L3–CBL complex. The significance of Y2H predictions was assessed by both mutagenesis and functional assays. Significantly, 74/80 (>92%) of Y2H predicted complexes were disrupted by point mutations that inhibit verified E2/E3-RING interactions, and a ?93% correlation was observed between Y2H data and the functional activity of E2/E3-RING complexes in vitro. Analysis of the high-density human E2/E3-RING network reveals complex combinatorial interactions and a strong potential for functional redundancy, especially within E2 families that have undergone evolutionary expansion. Finally, a one-step extended human E2/E3-RING network, containing 2644 proteins and 5087 edges, was assembled to provide a resource for future functional investigations. PMID:19549727

Markson, Gabriel; Kiel, Christina; Hyde, Russell; Brown, Stephanie; Charalabous, Panagoula; Bremm, Anja; Semple, Jennifer; Woodsmith, Jonathan; Duley, Simon; Salehi-Ashtiani, Kourosh; Vidal, Marc; Komander, David; Serrano, Luis; Lehner, Paul; Sanderson, Christopher M.

2009-01-01

248

Repression of Androgen Receptor Transcription through the E2F1/DNMT1 Axis  

PubMed Central

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

249

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

250

In vitro and in vivo estrogenic effects of 17alpha-estradiol in medaka (Oryzias latipes).  

PubMed

17alpha-Estradiol (17alpha-E2), the stereoisomer of 17beta-estradiol (17beta-E2), is considered a weak estrogen in mammals. However, little is known about its estrogenic potency in teleost fish, even though 17alpha-E2 has been frequently detected in aquatic environment. To investigate the estrogenic activity of 17alpha-E2, an in vitro assay based on the ligand-dependent interaction between medaka estrogen receptor alpha (med-ERalpha) and coactivator was conducted. Japanese medaka (Oryziaslatipes) were exposed to 1, 10, 100, 1000 and 10000ng L(-1) 17alpha-E2 (actual concentrations of 1.91, 12.81, 96.24, 1045.15, and 9320.81ng L(-1), respectively) for 3 weeks, and expression for vitellogenins (VTG-I), Choriogenin H (CHG-H) and estrogen receptor alpha (ERalpha) mRNA in the livers was analyzed by quantitative real-time RT-PCR (Q-RT-PCR). The in vitro study showed that the EC(50) of 17alpha-E2 was 114.10nM, which was 30 times less potent than that of 17beta-E2 (3.80nM). Dose-dependent induction of gene expression of VTG-I, CHG-H and ERalpha were observed. The benchmark dose (BMD) values for VTG-I, CHG-H and ERalpha were 44.16ng L(-1), 15.25ng L(-1) and 66.03ng L(-1), which were about 11-, 17- and 14-times less potent than that of 17beta-E2, respectively. Comparing this study with those reported previously in mammals, it is suggested that fish species may be more susceptive to 17alpha-E2 than mammals. PMID:20451236

Huang, Chong; Zhang, Zhaobin; Wu, Shimin; Zhao, Yanbin; Hu, Jianying

2010-07-01

251

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

E-print Network

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 ...

Selker, H P

252

Prostaglandins E1 and E2 prevent bronchoconstriction in the guinea-pig.  

PubMed

Prostaglandin E(1) and E(2) aerosols protected the guinea-pig against bronchoconstriction caused by anaphylactic microshock, 1% histamine, 4% acetylcholine and 1% 5-hydroxytryptamine aerosols. PMID:4425768

Herxheimer, H

1974-02-01

253

Prostaglandins E1 and E2 prevent bronchoconstriction in the guinea-pig  

PubMed Central

Prostaglandin E1 and E2 aerosols protected the guinea-pig against bronchoconstriction caused by anaphylactic microshock, 1% histamine, 4% acetylcholine and 1% 5-hydroxytryptamine aerosols. PMID:4425768

Herxheimer, H.

1974-01-01

254

29 CFR 2584.8477(e)-2 - Allocation of fiduciary duties.  

Code of Federal Regulations, 2010 CFR

...RESPONSIBILITY § 2584.8477(e)-2 Allocation of fiduciary duties. (a) The fiduciary duties of the Board as set forth at 5 U.S.C...members of the Board. (b) The Executive Director may allocate authority and...

2010-07-01

255

Relative intensities of ?-rays from E2 transitions in the decay of 180mHf  

NASA Astrophysics Data System (ADS)

The relative intensities of ?-rays from pure E2 transitions in the decay of 180mHf have been determined from measured conversion electron intensities and calculated K- and L-shell conversion coefficients.

Christmas, P.; Cross, P.

1980-08-01

256

Investigation of orbital momentum profiles of methylpropane ,,isobutane... by binary ,,e,2e... spectroscopy  

E-print Network

Investigation of orbital momentum profiles of methylpropane ,,isobutane... by binary ,,e,2e of the valence orbitals of methylpropane, also known as isobutane (CH3CH CH3 CH3), have been studied by using

Wang, Yayu

257

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

258

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

259

Uterine curettage following second trimester abortion by extraovular instillation of prostaglandin E 2  

Microsoft Academic Search

Objective: To evaluate the benefits associated with routine uterine curettage following complete second trimester termination of pregnancy by extraovular prostaglandin E2. Study design: Fifty-five patients between 15 and 24 weeks’ gestation who had undergone complete termination of pregnancy by continuous extraovular instillation of prostaglandin E2 (PGE2), were randomly assigned into either no further intervention (n=25), or uterine curettage under general

Jack Atad; Mordechai Hallak; Oren Fruchter; David Yshai; Ron Auslender; Haim Abramovici

1999-01-01

260

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

261

The E1–E2 center in gallium arsenide is the divacancy  

NASA Astrophysics Data System (ADS)

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.

Schultz, Peter A.

2015-02-01

262

Regression of human papillomavirus intraepithelial lesions is induced by MVA E2 therapeutic vaccine.  

PubMed

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

263

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

264

Analysis of a conserved RGE/RGD motif in HCV E2 in mediating entry  

PubMed Central

Background Hepatitis C virus (HCV) encodes two transmembrane glycoproteins E1 and E2 which form a heterodimer. E1 is believed to mediate fusion while E2 has been shown to bind cellular receptors. It is clear that HCV uses a multi-receptor complex to gain entry into susceptible cells, however key elements of this complex remain elusive. In this study, the role of a highly conserved RGE/RGD motif of HCV E2 glycoprotein in viral entry was examined. The effect of each substitution mutation in this motif was tested by challenging susceptible cell lines with mutant HCV E1E2 pseudotyped viruses generated using a lentiviral system (HCVpp). In addition to assaying infectivity, producer cell expression and HCVpp incorporation of HCV E2 proteins, CD81 binding profiles, and conformation of mutants were examined. Results Based on these characteristics, mutants either displayed wt characteristics (high infectivity [? 90% of wt HCVpp], CD81 binding, E1E2 expression, and incorporation into viral particles and proper conformation) or very low infectivity (? 20% of wt HCVpp). Only amino acid substitutions of the 3rd position (D or E) resulted in wt characteristics as long as the negative charge was maintained or a neutral alanine was introduced. A change in charge to a positive lysine, disrupted HCVpp infectivity at this position. Conclusion Although most amino acid substitutions within this conserved motif displayed greatly reduced HCVpp infectivity, they retained soluble CD81 binding, proper E2 conformation, and incorporation into HCVpp. Our results suggest that although RGE/D is a well-defined integrin binding motif, in this case the role of these three hyperconserved amino acids does not appear to be integrin binding. As the extent of conservation of this region extends well beyond these three amino acids, we speculate that this region may play an important role in the structure of HCV E2 or in mediating the interaction with other factor(s) during viral entry. PMID:19171049

Rothwangl, Katharina B; Rong, Lijun

2009-01-01

265

The Caudal homeodomain protein activates Drosophila E2F gene expression  

PubMed Central

The Drosophila caudal homeobox gene is required for definition of the anteroposterior axis and for gut development, and CDX1 and CDX2, human homologs, play crucial roles in the regulation of cell proliferation and differentiation in the intestine. Most studies have indicated tumor suppressor functions of Cdx2, with inhibition of proliferation, while the effects of Cdx1 are more controversial. The influence of Drosophila Caudal on cell proliferation is unknown. In this study, we found three potential Caudal binding sequences in the 5?-flanking region of the Drosophila E2F (DE2F) gene and showed by transient transfection assays that they are involved in Caudal transactivation of the dE2F gene promoter. Analyses with transgenic flies carrying an E2F-lacZ fusion gene, with and without mutation in the Caudal binding site, indicated that the Caudal binding sites are required for expression of dE2F in living flies. Caudal-induced E2F expression was also confirmed with a GAL4-UAS system in living flies. In addition, ectopic expression of Caudal with heat-shock promotion induced melanotic tumors in larvae. These results suggest that Caudal is involved in regulation of proliferation through transactivation of the E2F gene in Drosophila. PMID:12466526

Hwang, Mi-Sun; Kim, Young-Shin; Choi, Na-Hyun; Park, Jae-Hong; Oh, Eun-Jin; Kwon, Eun-Jeong; Yamaguchi, Masamitsu; Yoo, Mi-Ae

2002-01-01

266

Temperature Dependent E2 Raman Modes in the ZnCoO Ternary Alloy  

NASA Technical Reports Server (NTRS)

The anharmonic properties of low and high frequency E2 modes of ZnO and Co doped ZnO were investigated using Raman scattering spectroscopy. We have determined the behavior of frequency, linewidths, and lifetime of E2 modes in the temperature range from 80 to 800 K. In the case of E2(high) mode the frequency shift towards the lower energy side was analyzed in light of the theory of anharmonic phonon-phonon interaction and thermal expansion of the lattice, and the linewidth behavior was analyzed in terms of anharmonic effect of three-phonon decay mechanism. But in the case of E2(low), the linewidth and frequency behaved practically harmonic with respect to temperature and independent of Co substitutions. It is found that the E2(high) phonon anharmonicity is higher for ZnCoO alloys than in pure ZnO and it increases with the compositional disorder. The low temperature lifetime of E2 phonon in ZnO, 1 % and 3% Co doped ZnO were found to be 1.S2, 1.74, and 1.54 ps, respectively.

Samanta, K.; Bhattacharya, P.; Katiyar, R. S.

2007-01-01

267

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

268

miR-98 delays skeletal muscle differentiation by down-regulating E2F5.  

PubMed

A genome-wide screen had previously shown that knocking down miR-98 and let-7g, two miRNAs of the let-7 family, leads to a dramatic increase in terminal myogenic differentiation. In the present paper, we report that a transcriptomic analysis of human myoblasts, where miR-98 was knocked down, revealed that approximately 240 genes were sensitive to miR-98 depletion. Among these potential targets of miR-98, we identified the transcriptional repressor E2F5 and showed that it is a direct target of miR-98. Knocking down simultaneously E2F5 and miR-98 almost fully restored normal differentiation, indicating that E2F5 is involved in the regulation of skeletal muscle differentiation. We subsequently show that E2F5 can bind to the promoters of two inhibitors of terminal muscle differentiation, ID1 (inhibitor of DNA binding 1) and HMOX1 (heme oxygenase 1), which decreases their expression in skeletal myoblasts. We conclude that miR-98 regulates muscle differentiation by altering the expression of the transcription factor E2F5 and, in turn, of multiple E2F5 targets. PMID:25422988

Kropp, Jeremie; Degerny, Cindy; Morozova, Nadezda; Pontis, Julien; Harel-Bellan, Annick; Polesskaya, Anna

2015-02-15

269

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

270

Physical and functional interactions of human papillomavirus E2 protein with nuclear receptor coactivators  

SciTech Connect

In addition to the human papillomavirus (HPV)-induced immortalization of epithelial cells, which usually requires integration of the viral DNA into the host cell genome, steroid hormone-activated nuclear receptors (NRs) are thought to bind to specific DNA sequences within transcriptional regulatory regions on the long control region to either increase or suppress transcription of dependent genes. In this study, our data suggest that the NR coactivator function of HPV E2 proteins might be mediated through physical and functional interactions with not only NRs but also the NR coactivators GRIP1 (glucocorticoid receptor-interacting protein 1) and Zac1 (zinc-finger protein which regulates apoptosis and cell cycle arrest 1), reciprocally regulating their transactivation activities. GRIP1 and Zac1 both were able to act synergistically with HPV E2 proteins on the E2-, androgen receptor-, and estrogen receptor-dependent transcriptional activation systems. GRIP1 and Zac1 might selectively function with HPV E2 proteins on thyroid receptor- and p53-dependent transcriptional activation, respectively. Hence, the transcriptional function of E2 might be mediated through NRs and NR coactivators to regulate E2-, NR-, and p53-dependent transcriptional activations.

Wu, M.-H. [Graduate Institute of Life Sciences, National Defense Medical Center, Taipei City 114, Taiwan (China); Huang, C.-J. [Molecular Genetics and Biochemistry Laboratory, Cathay Medical Research Institute, Cathay General Hospital, Taipei County 221, Taiwan (China); Department of Biochemistry, National Defense Medical Center, Taipei City 114, Taiwan (China); Liu, S.-T. [Department of Biochemistry, National Defense Medical Center, Taipei City 114, Taiwan (China); Liu, P.-Y. [Graduate Institute of Life Sciences, National Defense Medical Center, Taipei City 114, Taiwan (China); Ho, C.-L. [Division of Hematology/Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei City 114, Taiwan (China); Huang, S.-M. [Graduate Institute of Life Sciences, National Defense Medical Center, Taipei City 114, Taiwan (China) and Department of Biochemistry, National Defense Medical Center, Taipei City 114, Taiwan (China)]. E-mail: shihming@ndmctsgh.edu.tw

2007-05-11

271

Pharmacokinetics and enterohepatic circulation of (E)-2-ene valproic acid in the rat.  

PubMed

A pharmacologically active monounsaturated metabolite of valproic acid (VPA), (E)-2-ene VPA, was administered by an intravenous bolus dose of 20 mg/kg to normal and bile-exteriorized rats. The total plasma clearance of (E)-2-ene VPA in normal rats was 4.9 ml/min/kg and in bile-exteriorized rats, 7.7 ml/min/kg. (E)-2-ene was recycled in the plasma of normal rats due to enterohepatic circulation. Approximately 32% of the dose was excreted in the urine of normal rats. Of the administered dose to bile exteriorized rats, approximately 27% was excreted in the urine and 38% in the bile. Administration of (E)-2-ene increased bile flow rate, and the induced choleresis lasted for 3-4 h. (E)-2-ene VPA was largely excreted in apparently conjugated form in the urine and bile. The pharmacokinetics of (E)-2-ene VPA were similar to that of the parent drug VPA. PMID:2095402

Singh, K; Orr, J M; Abbott, F S

1990-10-01

272

E2f4 is required for normal development of the airway epithelium  

PubMed Central

The airway epithelium is comprised of specialized cell types that play key roles in protecting the lungs from environmental insults. The cellular composition of the murine respiratory epithelium is established during development and different cell types populate specific regions along the airway. Here we show that E2f4-deficiency leads to an absence of ciliated cells from the entire airway epithelium and the epithelium of the submucosal glands in the paranasal sinuses. This defect is particularly striking in the nasal epithelium of E2f4?/? mice where ciliated cells are replaced by columnar secretory cells that produce mucin-like substances. In addition, in the proximal lung, E2f4-loss causes a reduction in Clara cell marker expression indicating that Clara cell development is also affected. These defects arise during embryogenesis and, in the nasal epithelium, appear to be independent of any changes in cell proliferation, the principal process regulated by members of the E2f family of transcription factors. We therefore conclude that E2f4 is required to determine the appropriate development of the airway epithelium. Importantly, the combination of no ciliated cells and excess mucous cells can account for the chronic rhinitis and increased susceptibility to opportunistic infections that causes the postnatal lethality of E2f4 mutant mice. PMID:17383628

Danielian, Paul S.; Bender Kim, Carla F.; Caron, Alicia M.; Vasile, Eliza; Bronson, Roderick T.; Lees, Jacqueline A.

2007-01-01

273

Inactivation of Rb and E2f8 Synergizes To Trigger Stressed DNA Replication during Erythroid Terminal Differentiation  

PubMed Central

Rb is critical for promoting cell cycle exit in cells undergoing terminal differentiation. Here we show that during erythroid terminal differentiation, Rb plays a previously unappreciated and unorthodox role in promoting DNA replication and cell cycle progression. Specifically, inactivation of Rb in erythroid cells led to stressed DNA replication, increased DNA damage, and impaired cell cycle progression, culminating in defective terminal differentiation and anemia. Importantly, all of these defects associated with Rb loss were exacerbated by the concomitant inactivation of E2f8. Gene expression profiling and chromatin immunoprecipitation (ChIP) revealed that Rb and E2F8 cosuppressed a large array of E2F target genes that are critical for DNA replication and cell cycle progression. Remarkably, inactivation of E2f2 rescued the erythropoietic defects resulting from Rb and E2f8 deficiencies. Interestingly, real-time quantitative PCR (qPCR) on E2F2 ChIPs indicated that inactivation of Rb and E2f8 synergizes to increase E2F2 binding to its target gene promoters. Taken together, we propose that Rb and E2F8 collaborate to promote DNA replication and erythroid terminal differentiation by preventing E2F2-mediated aberrant transcriptional activation through the ability of Rb to bind and sequester E2F2 and the ability of E2F8 to compete with E2F2 for E2f-binding sites on target gene promoters. PMID:24865965

Ghazaryan, Seda; Sy, Chandler; Hu, Tinghui; An, Xiuli; Mohandas, Narla; Fu, Haiqing; Aladjem, Mirit I.; Chang, Victor T.; Opavsky, Rene

2014-01-01

274

Histone Demethylase JMJD2B Functions as a Co-Factor of Estrogen Receptor in Breast Cancer Proliferation and Mammary Gland Development  

PubMed Central

Estrogen is a key regulator of normal function of female reproductive system and plays a pivotal role in the development and progression of breast cancer. Here, we demonstrate that JMJD2B (also known as KDM4B) constitutes a key component of the estrogen signaling pathway. JMJD2B is expressed in a high proportion of human breast tumors, and that expression levels significantly correlate with estrogen receptor (ER) positivity. In addition, 17-beta-estradiol (E2) induces JMJD2B expression in an ER? dependent manner. JMJD2B interacts with ER? and components of the SWI/SNF-B chromatin remodeling complex. JMJD2B is recruited to ER? target sites, demethylates H3K9me3 and facilitates transcription of ER responsive genes including MYB, MYC and CCND1. As a consequence, knockdown of JMJD2B severely impairs estrogen-induced cell proliferation and the tumor formation capacity of breast cancer cells. Furthermore, Jmjd2b-deletion in mammary epithelial cells exhibits delayed mammary gland development in female mice. Taken together, these findings suggest an essential role for JMJD2B in the estrogen signaling, and identify JMJD2B as a potential therapeutic target in breast cancer. PMID:21445275

Kawazu, Masahito; McQuire, Tracy; Goto, Kouichiro; Son, Dong-Ok; Wakeham, Andrew; Miyagishi, Makoto; Mak, Tak W.; Okada, Hitoshi

2011-01-01

275

Reproductive disruption in wild longear sunfish (Lepomis megalotis) exposed to kraft mill effluent.  

PubMed

Worldwide, wild fish living in rivers receiving municipal and industrial discharges may experience endocrine disruption as a result of exposure to anthropogenic pollutants. The purpose of this study was to evaluate the hormonal status of wild fish in a U.S. river receiving unbleached kraft and recycled pulp mill effluent (Pearl River at Bogalusa, LA). We evaluated two alternative hypotheses: the effluent contained constituents that suppressed male and female reproduction, or it contained an androgenic substance that masculinized females. To evaluate the likelihood of fish exposure to effluent, we marked 697 longear sunfish (Lepomis megalotis) over a 2-year period; 83% of recaptured fish were found at the site of initial capture, and only one fish migrated from an effluent-receiving site to a reference site. We can reasonably assume that fish captured from an effluent-receiving site are residents, not transitory migrants. To diagnose endocrine disruption, we measured sex steroid hormone [17beta-estradiol (E2), testosterone (T), and 11-ketotestosterone (11KT)] and vitellogenin (VTG) concentrations in male and female longear sunfish captured at two sites upstream and two sites downstream of the effluent outfall. Kraft pulp mill effluent did not affect male reproductive physiology but did suppress female T and VTG levels when effluent constituted>or=1% of river flow. Masculinization was not observed. Longear sunfish in the Pearl River experience moderate reproductive suppression in response to unbleached kraft and recycled pulp mill effluent. PMID:16393656

Fentress, Jennifer A; Steele, Stacy L; Bart, Henry L; Cheek, Ann Oliver

2006-01-01

276

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

277

Hypertrophy of gonadotropin releasing hormone-containing neurons after castration in the teleost, Haplochromis burtoni.  

PubMed

In the African cichlid fish, Haplochromis burtoni, males are either territorial or nonterritorial. Territorial males suppress reproductive function in the nonterritorial males, and have larger gonads and larger gonadotropin-releasing hormone- (GnRH) containing neurons in the preoptic area (POA). We describe an experiment designed to establish the causal relationship between large GnRH neurons and large testes in these males by determining the feedback effects of gonadal sex steroids on the GnRH neurons. Territorial males were either castrated or sham-operated, 4 weeks after which they were sacrificed. Circulating steroid levels were measured, and the GnRH-containing neurons were visualized by staining sagittal sections of the brains with an antibody to salmon GnRH. The soma areas of antibody-stained neurons were measured with a computer-aided imaging system. Completely castrated males had markedly reduced levels of circulating sex steroids [11-ketotestosterone (11KT) and testosterone (T)], as well as 17 beta-estradiol (E2). POA GnRH neurons in castrates showed a significant increase in mean soma size relative to the intact territorial males. Hence, in mature animals, gonadal steroids act as a brake on the growth of GnRH-containing neurons, and gonadal products are not responsible for the large GnRH neurons characteristic of territorial males. PMID:1460466

Francis, R C; Jacobson, B; Wingfield, J C; Fernald, R D

1992-10-01

278

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

279

Effect of xenoestrogen exposure on the expression of cytochrome P450 isoforms in rainbow trout liver.  

PubMed

We studied the estrogenic effects of model chemicals in one-year-old juvenile rainbow trout. Methoxychlor (20 mg/kg), diethylstilbestrol (15 mg/kg), 4-tert-octylphenol (25 and 50 mg/kg), and biochanin A (25 and 50 mg/kg) were injected intraperitoneally on days 1, 4, and 7. Fish were sacrificed on day 9 and examined for multiple biomarkers. All of the test chemicals caused increases in plasma vitellogenin levels, a biomarker of estrogenicity. Treatment with the xenoestrogens decreased hepatic lauric acid hydroxylase activity and, as shown by Western blots, also generally reduced expression of hepatic cytochrome P450s 2K1 (CYP2K1), 2M1 (CYP2M1), and 3A27 (CYP3A27) at the protein level. Both doses of biochanin A also significantly induced P4501A (CYPIA) and greatly increased hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity. These findings suggest that methoxychlor, diethylstilbestrol, 4-tert-octylphenol, and biochanin A were all estrogenic and mimicked 17beta-estradiol (E2) in repressing the expression of cytochrome P450 isoforms (CYP2KI, CYP2M1, and CYP3A27) in the rainbow trout liver. Additionally, biochanin A was found to induce CYPIA in this fish species. PMID:12389925

Katchamart, Sirinmas; Miranda, Cristobal L; Henderson, Marilyn C; Pereira, Clifford B; Buhler, Donald R

2002-11-01

280

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

PubMed

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

281

Distinct regulation by steroids of messenger RNAs for FSHR and CYP19A1 in bovine granulosa cells.  

PubMed

Steroidal regulation of gene expression in follicular cells is not completely defined. Granulosa cells from 5 mm bovine follicles were cultured and treated and steady-state mRNA levels determined for FSHR (follicle-stimulating hormone receptor) and CYP19A1 (aromatase). Cells were treated for 5 days with (0.1-300 ng/ml) 17beta-estradiol (E2), testosterone (T), or 5alpha-dihydrotestosterone (DHT). FSHR mRNA was increased by T and DHT but not E2. In contrast, CYP19A1 mRNA was induced by all doses of E2 but only high doses of T and DHT. Similarly, varying treatment duration (1-5 days) showed that FSHR was increased by T and DHT and CYP19A1 mRNA increased by E2 and T at all times. Synergism between steroid hormones and FSH or forskolin was also evaluated. FSH or E2 did not alter FSHR mRNA and did not enhance DHT stimulation of FSHR mRNA. In contrast, DHT alone had no effect on CYP19A1 mRNA but synergized with FSH plus E2 to increase CYP19A1 mRNA, probably due to induction of FSHR by DHT. Effects of E2 and T on CYP19A1 were blocked by ICI 182,780, indicating mediation by estrogen receptors. However, the specific androgen receptor antagonist bicalutamide did not block E2 or T effects on CYP19A1 but did block T and DHT stimulation of FSHR. Thus, FSHR is specifically regulated through androgen receptor, whereas CYP19A1 is regulated by multiple pathways, including estrogen receptors and cAMP/protein kinase A induced by FSHR activation in granulosa cells. These inter- and intracellular regulatory mechanisms may be critical for normal follicle growth and dominant follicle selection. PMID:16641147

Luo, Wenxiang; Wiltbank, Milo C

2006-08-01

282

The adenovirus E4 gene, in addition to the E1A gene, is important for trans-activation of E2 transcription and for E2F activation  

SciTech Connect

Previous experiments have demonstrated that adenovirus infection of human and mouse cells leads to an E1A-dependent activation of the DNA-binding capacity of a cellular transcription factor termed E2F. E2F binds to two sites in the adenovirus E2 early promoter which have been shown to be critical for E1A-dependent E2 early transcription, and the E2F-binding sites can confer E1A-induced transcription to a heterologous promoter. In addition, under a variety of circumstances, the increase in E2F-binding activity coincides with the activation of E2 transcription. The authors now find that, in addition to the E1A gene, another early viral gene, the E4 gene, is necessary for the activation of E2F-binding activity. Extracts prepared from human 293 cells, which express the E1A and E1B genes, had low levels of E2F activity, whereas infection of 293 cells with the E1A mutant dl312 increased E2F activity. A coinfection with the two mutants yielded the normal wild-type increase in E2F. Furthermore, infection of HeLa cells with a high multiplicity of dl312 did not yield an increase in E2F activity. Thus, it appears that both the E1A gene and the E4 gene are directly involved in E2F activation. Measurements of E2 RNA production in a dl366 infection as compared with a wild-type or dl312 infection demonstrate that the E4 gene is essential for full E2 transcription. They conclude that the activation of the E2F factor leading to the activation of E2 transcription requires the combined action of both the E1A 289-amino-acid protein and an E4 product.

Reichel, R.; Neill, S.D.; Kovesdi, I.; Simon, M.C.; Raychaudhuri, P.; Nevins, J.R. (Duke Univ. Medical Center, Durham, NC (USA))

1989-09-01

283

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

284

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

285

Positive cross-talk between estrogen receptor and NF-kappaB in breast cancer.  

PubMed

Estrogen receptors (ER) and nuclear factor-kappaB (NF-kappaB) are known to play important roles in breast cancer, but these factors are generally thought to repress each other's activity. However, we have recently found that ER and NF-kappaB can also act together in a positive manner to synergistically increase gene transcription. To examine the extent of cross-talk between ER and NF-kappaB, a microarray study was conducted in which MCF-7 breast cancer cells were treated with 17beta-estradiol (E(2)), tumor necrosis factor alpha (TNFalpha), or both. Follow-up studies with an ER antagonist and NF-kappaB inhibitors show that cross-talk between E(2) and TNFalpha is mediated by these two factors. We find that although transrepression between ER and NF-kappaB does occur, positive cross-talk is more prominent with three gene-specific patterns of regulation: (a) TNFalpha enhances E(2) action on approximately 30% of E(2)-upregulated genes; (b) E(2) enhances TNFalpha activity on approximately 15% of TNFalpha-upregulated genes; and (c) E(2) + TNFalpha causes a more than additive upregulation of approximately 60 genes. Consistent with their prosurvival roles, ER and NF-kappaB and their target gene, BIRC3, are involved in protecting breast cancer cells against apoptosis. Furthermore, genes positively regulated by E(2) + TNFalpha are clinically relevant because they are enriched in luminal B breast tumors and their expression profiles can distinguish a cohort of patients with poor outcome following endocrine treatment. Taken together, our findings suggest that positive cross-talk between ER and NF-kappaB is more extensive than anticipated and that these factors may act together to promote survival of breast cancer cells and progression to a more aggressive phenotype. PMID:19920189

Frasor, Jonna; Weaver, Aisha; Pradhan, Madhumita; Dai, Yang; Miller, Lance D; Lin, Chin-Yo; Stanculescu, Adina

2009-12-01

286

An E2F1-HOXB9 Transcriptional Circuit Is Associated with Breast Cancer Progression  

PubMed Central

Homeobox B9 (HOXB9), a member of the homeobox gene family, is overexpressed in breast cancer and promotes tumor progression and metastasis by stimulating epithelial-to-mesenchymal transition and angiogenesis within the tumor microenvironment. HOXB9 activates the TGF?-ATM axis, leading to checkpoint activation and DNA repair, which engenders radioresistance in breast cancer cells. Despite detailed reports of the role of HOXB9 in breast cancer, the factors that regulate HOXB9 transcription have not been extensively examined. Here we uncover an underlying mechanism that may suggest novel targeting strategies for breast cancer treatment. To identify a transcription factor binding site (TFBS) in the HOXB9 promoter region, a dual luciferase reporter assay was conducted. Protein candidates that may directly attach to a TFBS of HOXB9 were examined by Q-PCR, electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), and mutation analysis. A HOXB9 promoter region from ?404 to ?392 was identified as TFBS, and E2F1 was a potential binding candidate in this region. The induction of HOXB9 expression by E2F1 was observed by Q-PCR in several breast cancer cell lines overexpressing E2F1. The stimulatory effect of E2F1 on HOXB9 transcription and its ability to bind the TFBS were confirmed by luciferase, EMSA and ChIP assay. Immunohistochemical analysis of 139 breast cancer tissue samples revealed a significant correlation between E2F1 and HOXB9 expression (p<0.001). Furthermore, a CDK4/6 inhibitor suppressed E2F1 expression and also reduced expression of HOXB9 and its downstream target genes. Our in vitro analysis identified the TFBS of the HOXB9 promoter region and suggested that E2F1 is a direct regulator of HOXB9 expression; these data support the strong correlation we found between E2F1 and HOXB9 in clinical breast cancer samples. These results suggest that targeting the E2F1/HOXB9 axis may be a novel strategy for the control or prevention of cancer progression and metastasis. PMID:25136922

Zhussupova, Aisulu; Hayashida, Tetsu; Takahashi, Maiko; Miyao, Kazuhiro; Okazaki, Hiroshi; Jinno, Hiromitsu; Kitagawa, Yuko

2014-01-01

287

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

288

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

289

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

290

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

291

Functional Analysis of Cell Surface-Expressed Hepatitis C Virus E2 Glycoprotein  

PubMed Central

Hepatitis C virus (HCV) glycoproteins E1 and E2, when expressed in eukaryotic cells, are retained in the endoplasmic reticulum (ER). C-terminal truncation of E2 at residue 661 or 715 (position on the polyprotein) leads to secretion, consistent with deletion of a proposed hydrophobic transmembrane anchor sequence. We demonstrate cell surface expression of a chimeric glycoprotein consisting of E2 residues 384 to 661 fused to the transmembrane and cytoplasmic domains of influenza A virus hemagglutinin (HA), termed E2661-HATMCT. The E2661-HATMCT chimeric glycoprotein was able to bind a number of conformation-dependent monoclonal antibodies and a recombinant soluble form of CD81, suggesting that it was folded in a manner comparable to “native” E2. Furthermore, cell surface-expressed E2661-HATMCT demonstrated pH-dependent changes in antigen conformation, consistent with an acid-mediated fusion mechanism. However, E2661-HATMCT was unable to induce cell fusion of CD81-positive HEK cells after neutral- or low-pH treatment. We propose that a stretch of conserved, hydrophobic amino acids within the E1 glycoprotein, displaying similarities to flavivirus and paramyxovirus fusion peptides, may constitute the HCV fusion peptide. We demonstrate that influenza virus can incorporate E2661-HATMCT into particles and discuss experiments to address the relevance of the E2-CD81 interaction for HCV attachment and entry. PMID:10400776

Flint, Mike; Thomas, Joanne M.; Maidens, Catherine M.; Shotton, Christine; Levy, Shoshana; Barclay, Wendy S.; McKeating, Jane A.

1999-01-01

292

Acetylation of conserved lysines in bovine papillomavirus E2 by p300.  

PubMed

The p300, CBP, and pCAF lysine acetyltransferase (KAT) proteins have been reported to physically interact with bovine (BPV) and human (HPV) papillomavirus E2 proteins. While overexpression of these KAT proteins enhances E2-dependent transcription, the mechanism has not been determined. Using RNA interference (RNAi) to deplete these factors, we demonstrated that E2 transcriptional activity requires physiological levels of p300, CBP, and pCAF. Each protein appears to have a unique function in E2-dependent transcription, since overexpression of one KAT failed to compensate for RNAi knockdown of another KAT. Using an in vitro acetylation assay, we identified highly conserved lysines that are targeted by p300 for acetylation. The conservative changes of lysines at positions 111 and 112 to arginine were of particular interest. The K111R and the K111R/K112R mutants showed reduced transcriptional activity that was not responsive to p300 overexpression, while the K112R mutant retained activity. p300 and CBP were detected at the viral promoter; however, pCAF was not. We propose a model by which E2 transcriptional activity is controlled by p300-mediated acetylation of lysine 111. This model represents a novel mechanism regulating papillomavirus gene expression. PMID:23152516

Quinlan, Edward J; Culleton, Sara P; Wu, Shwu-Yuan; Chiang, Cheng-Ming; Androphy, Elliot J

2013-02-01

293

E2?Ub conjugates regulate the kinase activity of Shigella effector OspG during pathogenesis  

PubMed Central

Pathogenic bacteria introduce effector proteins directly into the cytosol of eukaryotic cells to promote invasion and colonization. OspG, a Shigella spp. effector kinase, plays a role in this process by helping to suppress the host inflammatory response. OspG has been reported to bind host E2 ubiquitin-conjugating enzymes activated with ubiquitin (E2?Ub), a key enzyme complex in ubiquitin transfer pathways. A co-crystal structure of the OspG/UbcH5c?Ub complex reveals that complex formation has important ramifications for the activity of both OspG and the UbcH5c?Ub conjugate. OspG is a minimal kinase domain containing only essential elements required for catalysis. UbcH5c?Ub binding stabilizes an active conformation of the kinase, greatly enhancing OspG kinase activity. In contrast, interaction with OspG stabilizes an extended, less reactive form of UbcH5c?Ub. Recognizing conserved E2 features, OspG can interact with at least ten distinct human E2s?Ub. Mouse oral infection studies indicate that E2?Ub conjugates act as novel regulators of OspG effector kinase function in eukaryotic host cells. PMID:24446487

Pruneda, Jonathan N; Smith, F Donelson; Daurie, Angela; Swaney, Danielle L; Villén, Judit; Scott, John D; Stadnyk, Andrew W; Le Trong, Isolde; Stenkamp, Ronald E; Klevit, Rachel E; Rohde, John R; Brzovic, Peter S

2014-01-01

294

The Cellular Bromodomain Protein Brd4 has Multiple Functions in E2-Mediated Papillomavirus Transcription Activation  

PubMed Central

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

2014-01-01

295

Role of E2-Ub-conjugating enzymes during skeletal muscle atrophy  

PubMed Central

The Ubiquitin Proteasome System (UPS) is a major actor of muscle wasting during various physio-pathological situations. In the past 15 years, increasing amounts of data have depicted a picture, although incomplete, of the mechanisms implicated in myofibrillar protein degradation, from the discovery of muscle-specific E3 ligases to the identification of the signaling pathways involved. The targeting specificity of the UPS relies on the capacity of the system to first recognize and then label the proteins to be degraded with a poly-ubiquitin (Ub) chain. It is fairly assumed that the recognition of the substrate is accomplished by the numerous E3 ligases present in mammalian cells. However, most E3s do not possess any catalytic activity and E2 enzymes may be more than simple Ub-providers for E3s since they are probably important actors in the ubiquitination machinery. Surprisingly, most authors have tried to characterize E3 substrates, but the exact role of E2s in muscle protein degradation is largely unknown. A very limited number of the 35 E2s described in humans have been studied in muscle protein breakdown experiments and the vast majority of studies were only descriptive. We review here the role of E2 enzymes in skeletal muscle and the difficulties linked to their study and provide future directions for the identification of muscle E2s responsible for the ubiquitination of contractile proteins.

Polge, Cecile; Attaix, Didier; Taillandier, Daniel

2015-01-01

296

A Complex with Chromatin Modifiers That Occupies E2F- and Myc-Responsive Genes in G0 Cells  

Microsoft Academic Search

E2F-6 contributes to gene silencing in a manner independent of retinoblastoma protein family members. To better elucidate the molecular mechanism of repression by E2F-6, we have purified the factor from cultured cells. E2F-6 is found in a multimeric protein complex that contains Mga and Max, and thus the complex can bind not only to the E2F-binding site but also to

Hidesato Ogawa; Kei-ichiro Ishiguro; Stefan Gaubatz; David M. Livingston; Yoshihiro Nakatani

2002-01-01

297

E2F-1 Gene Transfer Enhances Invasiveness of Human Head and Neck Carcinoma Cell Lines1  

Microsoft Academic Search

The transcription factor E2F-1, a downstream regulator of the p16- cyclinD-Rb pathway, is required for cell cycle progression. Evidence shows that overexpression of E2F-1 can either promote or inhibit devel- opment of tumors, depending on tissue or experimental conditions. To study whether the E2F-1 gene plays a role in tumor progression, the expression of E2F-1 protein was evaluated in 10

Shi Yu Zhang; Shao Chen Liu; David G. Johnson; Andres J. P. Klein-Szanto

2000-01-01

298

The Disulfide Bonds in Glycoprotein E2 of Hepatitis C Virus Reveal the Tertiary Organization of the Molecule  

E-print Network

The Disulfide Bonds in Glycoprotein E2 of Hepatitis C Virus Reveal the Tertiary Organization envelope glycoproteins E1 and E2 are scarce, in spite of their essential role in the viral life cycle'Alayer J, Kikuti CM, Saulnier A, Damier-Piolle L, et al. (2010) The Disulfide Bonds in Glycoprotein E2

Paris-Sud XI, Université de

299

Imperial College London EEE 1A1 Autumn 2008 E2.2 Analogue Electronics Rational Transfer functions and  

E-print Network

Imperial College London ­ EEE 1A1 Autumn 2008 E2.2 Analogue Electronics Rational Transfer functions and the Bode Plot #12;Imperial College London ­ EEE 2A1 Autumn 2008 E2.2 Analogue Electronics The transfer s = = - - - = = = - - - 0 j t V V e + = #12;Imperial College London ­ EEE 3A1 Autumn 2008 E2.2 Analogue Electronics

Papavassiliou, Christos

300

Imperial College London EEE 1L2 Autumn 2009 E2.2 Analogue Electronics The Miller Theorem  

E-print Network

Imperial College London ­ EEE 1L2 Autumn 2009 E2.2 Analogue Electronics The Miller Theorem and the Frequency Response of the Common Emitter Amplifier #12;Imperial College London ­ EEE 2L2 Autumn 2009 E2)Y (1+1/G)Y #12;Imperial College London ­ EEE 3L2 Autumn 2009 E2.2 Analogue Electronics An application

Papavassiliou, Christos

301

Imperial College London EEE 1L3 Autumn 2009 E2.2 Analogue Electronics Feedback amplifiers  

E-print Network

Imperial College London ­ EEE 1L3 Autumn 2009 E2.2 Analogue Electronics Feedback amplifiers29-41 #12;Imperial College London ­ EEE 2L3 Autumn 2009 E2.2 Analogue Electronics Circuits using College London ­ EEE 3L3 Autumn 2009 E2.2 Analogue Electronics · Keep all the properties of the ideal op

Papavassiliou, Christos

302

Imperial College London EEE 1L7 Autumn 2009 E2.2 Analogue Electronics Active Filters  

E-print Network

Imperial College London ­ EEE 1L7 Autumn 2009 E2.2 Analogue Electronics Active Filters Motivation · Design electronically programmable filters #12;Imperial College London ­ EEE 2L7 Autumn 2009 E2 sine Low Pass High Pass Band Pass Band Reject #12;Imperial College London ­ EEE 3L7 Autumn 2009 E2

Papavassiliou, Christos

303

Characterization of Recombinant Monoclonal IgA Anti PDC-E2 Autoantibodies Derived From Patients With PBC  

E-print Network

Characterization of Recombinant Monoclonal IgA Anti­ PDC-E2 Autoantibodies Derived From Patients antibody isotype. In this study, we produced recombinant pyruvate dehydrogenase complex (PDC-E2)­ specific dimeric human IgA monoclonal antibodies (mAbs) in a baculovirus expression system. By using 2 anti­PDC-E2

Hammock, Bruce D.

304

An E2F1-Dependent Gene Expression Program That Determines the Balance Between Proliferation and Cell Death  

PubMed Central

Summary The Rb/E2F pathway regulates the expression of genes essential for cell proliferation but that also trigger apoptosis. During normal proliferation, PI3K/Akt signaling blocks E2F1 induced apoptosis, thus serving to balance proliferation and death. We now identify a subset of E2F1 target genes that are specifically repressed by PI3K/Akt signaling, thus distinguishing the E2F1 proliferative or apoptotic function. RNAi-mediated inhibition of several of these PI3K-repressed E2F1 target genes, including AMPK?2, impairs apoptotic induction by E2F1. Activation of AMPK?2 with an AMP analog further stimulates E2F1 induced apoptosis. We also show that the presence of the E2F1 apoptotic expression program in breast and ovarian tumors coincides with good prognosis, emphasizing the importance of the balance in the E2F1 proliferation/apoptotic program. Significance E2F1 has been shown to induce both proliferation and apoptosis. We now show that PI3K/Akt signaling regulates the balance of these events by specifically blocking expression of genes in the E2F1 apoptotic program but not the proliferative program. We further show that an alteration in the balance of the E2F1 program coincides with poor prognosis in both breast and ovarian cancer emphasizing the importance of these events for a clinical cancer phenotype. PMID:18167336

Hallstrom, Timothy C.; Mori, Seiichi; Nevins, Joseph R.

2008-01-01

305

Prostaglandin E2 regulates amyloid precursor protein expression via the EP2 receptor in cultured rat microglia  

E-print Network

Prostaglandin E2 regulates amyloid precursor protein expression via the EP2 receptor in cultured Abstract We investigated the effects of prostaglandin E2 (PGE2) on amyloid precursor protein (APP prostaglandin E2 (PGE2). In brains of AD patients, the activation of such components of this pathway as PLA2 [21

Wurtman, Richard

306

Prostaglandin E2 and misoprostol induce neurite retraction in Neuro-2a cells Javaneh Tamiji b,c  

E-print Network

Prostaglandin E2 and misoprostol induce neurite retraction in Neuro-2a cells Javaneh Tamiji b June 2010 Keywords: Prostaglandin E2 (PGE2) Misoprostol Growth cone Calcium transients Differentiation Autism a b s t r a c t Prostaglandin E2 (PGE2) is a key lipid-derived compound which mediates important

Crawford, Dorota A.

307

Prostaglandin E2 Receptor, EP3, Is Induced in Diabetic Islets and Negatively Regulates Glucose-and Hormone-  

E-print Network

Prostaglandin E2 Receptor, EP3, Is Induced in Diabetic Islets and Negatively Regulates Glucose is stimulated by prostaglandin E2 (PGE2) and cou- ples to G-proteins of the Gi subfamily to decrease- glandin (PG)E2, termed prostaglandin E receptor 3 (EP3), the only one of four PGE2 receptors that couples

Attie, Alan D.

308

Relations Involving Static Quadrupole Moments of $2^+$ states and B(E2)'s  

E-print Network

We define the ``quadrupole ratio'' $r_Q = \\dfrac{Q_0(S)}{Q_0(B)}$ where $Q_0(S)$ is the intrinsic quadrupole moment obtained from the static quadrupole moment of the $2_1^+$ state of an even-even nucleus and $Q_0(B)$ the intrinsic quadrupole moment obtained from $B(E2)_{0 \\to 2}$. In both cases we assume a simple rotational formula connecting the rotating frame to the laboratory frame. The quantity $r_Q$ would be one if the rotational model were perfect and the energy ratio $E(4)/E(2)$ would be 10/3. In the simple vibrational model, $r_Q$ would be zero and $E(4)/E(2)$ would be two. There are some regions where the rotational limit is almost met and fewer where the vibrational limit is also almost met. For most cases, however, it is between these two limits, i.e. $0 light nuclei.

Sean Yeager; Larry Zamick

2008-08-28

309

miR-31 promotes proliferation of colon cancer cells by targeting E2F2.  

PubMed

MicroRNA-31 (miR-31) plays important roles in colon cancer development. However, the underlying mechanism is still not clear. We have explored the functions of miR-31 on proliferation of colon cancer cells as well as the underlying mechanism. E2F2 was identified as a direct target of miR-31. miR-31 regulated the proliferation of colon cancer cells by targeting E2F2. Moreover, in the present study, E2F2 acted as a tumor suppressor in colon cancer by repressing the expression of survivin and regulating the expression of CCNA2, C-MYC, MCM4 and CDK2. A possible mechanism for the function of miR-31 on colon cancer proliferation is presented and indicates that miR-31 might become a target for anti-cancer drug design. PMID:25362258

Li, Tong; Luo, Wenjing; Liu, Kunmei; Lv, Xiaobo; Xi, Tao

2015-03-01

310

Structure and expression of the ColE2-P9 immunity gene.  

PubMed Central

The primary structure and expression of the ColE2-P9 immunity gene (imm) were investigated. The imm gene is located behind the colicin gene (col) in the same orientation with an intergenic space of two base pairs. Although the imm gene was transcribed primarily in response to the SOS function of the host cell as well as the col gene, the immunity phenotype also appeared to be expressed by only a slight level of leaky transcription without an evident promoter. On comparing the ColE2-P9 sequence with those of relevant plasmids, a highly homologous sequence with the immE2 gene was found downstream of the immE3 gene of ColE3-CA38, and thus, an evolutional relationships could be deduced among some E-group Col plasmids. PMID:2987833

Masaki, H; Toba, M; Ohta, T

1985-01-01

311

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

312

TGF{beta}-mediated formation of pRb-E2F complexes in human myeloid leukemia cells  

SciTech Connect

TGF{beta} is well known for its inhibitory effect on cell cycle G1 checkpoint kinases. However, its role in the control of pRb-E2F complexes is not well established. TGF{beta} inhibits phosphorylation of pRb at several serine and threonine residues and regulates the association of E2F transcription factors with pRb family proteins. Recent studies found that predominantly E2F-4, p130, and histone deacetylase (HDAC) are found to bind to corresponding E2F-responsive promoters in G0/G1 phase. As cells progress through mid-G1, p130-E2F4 complex are replaced by p107-E2F4 followed by activators E2F1, 2, and 3. pRb was not detectable in the promoters containing the E2F-responsive site in cycling cells but was associated with E2F4-p130 complexes or E2F4-p107 complexes during G0/G1 phase. In human myeloid leukemia cell line, MV4-11, TGF{beta} upregulated pRb-E2F-4 and p130-E2F-4, and downregulated p107-E2F-4 complexes. However, pRB-E2F1 and pRb-E2F3 complexes were found in proliferating cells but not in TGF{beta} arrested G1 cells. In addition, electrophoretic gel mobility shift assay (EMSA) could not detect pRb-E2F DNA-binding activities either in S or G1 phase but exhibited the existence of p107-E2F4 in proliferating cells and p130-E2F4 complexes in TGF{beta}-arrested G1 cells, respectively. Our data suggest that p107 and p130, but not pRb, and the repressor E2F, but not activator E2Fs, play a critical role in regulating E2F-responsive gene expression in TGF{beta}-mediated cell cycle control in human myeloid leukemia cells.

Hu Xiaotang [School of Natural and Health Science, Barry University, 11300 Northeast Second Avenue, Miami Shores, FL 33161 (United States)], E-mail: xthu@mail.barry.edu

2008-05-02

313

Administration of estradiol (E2), trenbolone acetate (TBA), and TBA/E2 implants alters adipogenic and myogenic gene expression in bovine skeletal muscle.  

PubMed

Twenty crossbred yearling steers (421 kg) were used to evaluate the effects of implanting with trenbolone acetate (TBA; 120 mg), estradiol-17? (E(2); 25.7 mg), and the combination (120 mg TBA and 24 mg E(2)) on adipogenic and myogenic mRNA concentrations. Animals were blocked by BW, and within each block, assigned to 1 of 4 treatments. Animals were housed and fed in individual pens with 5 animals per treatment. All animals were weighed weekly, and muscle biopsy samples were taken from the LM of each steer on d 0 (prior to implantation), d 7, d 14, and d 28. Total RNA was isolated from each sample and real-time quantitative PCR was used to measure the quantity of C/EBP?, PPAR?, stearoyl CoA desaturase (SCD), myogenin, and 3 isoforms of bovine myosin heavy chain (MHC) mRNA. Total BW gain from the 28-d period was adjusted to d 0 by use of covariant analysis, and implant group tended (P = 0.09) to increase BW gain over non-implanted control (CON) steers. Analysis of the gene expression of MHC showed that neither implant nor day (P > 0.20) had a significant effect on the expression of type-I or -IIX MHC mRNA There was also no treatment effect on MHC-IIA and myogenin, but increasing days on feed increased (P = 0.05) the expression of MHC-IIA mRNA. Relative mRNA levels of C/EBP?, PPAR?, and SCD increased (P < 0.05) during days of feed but PPAR? decreased (P < 0.05) with the treatment of combined TBA/E(2) implant. Results of this study indicate that implanting with TBA, E(2), or both increased BW gain and decreased adipogenic gene expression of finishing steers without significantly affecting the concentration of type-I, -IIA, or -IIX MHC mRNA. Increasing days on feed increased both the levels of MHC-IIA and adipogenic gene expression in bovine skeletal muscle biopsy samples. We conclude that administration of steroidal implants had no effect on the proportion of the 3 different MHC mRNA isoforms but decreased C/EBP?, PPAR?, and SCD mRNA in bovine skeletal muscle. PMID:22147484

Chung, K Y; Baxa, T J; Parr, S L; Luqué, L D; Johnson, B J

2011-12-01

314

Tetrocarcins E1, E2, F and F-1, new antibiotics. Fermentation, isolation and characterization.  

PubMed

New components of tetrocarcins (E1, E2, F and F-1) were found in the culture broth of Micromonospora chalcea KY 11091 that was known to produce tetrocarcins A, B and C. Tetrocarcin F-1 consisted of tetronolide and nitro sugar (tetronitrose). Tetrocarcins E1 and E2 consisted of F-1 and deoxy sugar (L-digitoxose). Tetrocarcin F consisted of F-1 and two deoxy sugars (their structures were not yet determined). They all showed antibacterial activities against Gram-positive bacteria and the specific activity decreased with decrease in the numbers of deoxy sugars attached to the aglycone. PMID:7142015

Tamaoki, T; Kasai, M; Shirahata, K; Tomita, F

1982-08-01

315

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

316

E2F5 status significantly improves malignancy diagnosis of epithelial ovarian cancer  

PubMed Central

Background Ovarian epithelial cancer (OEC) usually presents in the later stages of the disease. Factors, especially those associated with cell-cycle genes, affecting the genesis and tumour progression for ovarian cancer are largely unknown. We hypothesized that over-expressed transcription factors (TFs), as well as those that are driving the expression of the OEC over-expressed genes, could be the key for OEC genesis and potentially useful tissue and serum markers for malignancy associated with OEC. Methods Using a combination of computational (selection of candidate TF markers and malignancy prediction) and experimental approaches (tissue microarray and western blotting on patient samples) we identified and evaluated E2F5 transcription factor involved in cell proliferation, as a promising candidate regulatory target in early stage disease. Our hypothesis was supported by our tissue array experiments that showed E2F5 expression only in OEC samples but not in normal and benign tissues, and by significantly positively biased expression in serum samples done using western blotting studies. Results Analysis of clinical cases shows that of the E2F5 status is characteristic for a different population group than one covered by CA125, a conventional OEC biomarker. E2F5 used in different combinations with CA125 for distinguishing malignant cyst from benign cyst shows that the presence of CA125 or E2F5 increases sensitivity of OEC detection to 97.9% (an increase from 87.5% if only CA125 is used) and, more importantly, the presence of both CA125 and E2F5 increases specificity of OEC to 72.5% (an increase from 55% if only CA125 is used). This significantly improved accuracy suggests possibility of an improved diagnostics of OEC. Furthermore, detection of malignancy status in 86 cases (38 benign, 48 early and late OEC) shows that the use of E2F5 status in combination with other clinical characteristics allows for an improved detection of malignant cases with sensitivity, specificity, F-measure and accuracy of 97.92%, 97.37%, 97.92% and 97.67%, respectively. Conclusions Overall, our findings, in addition to opening a realistic possibility for improved OEC diagnosis, provide an indirect evidence that a cell-cycle regulatory protein E2F5 might play a significant role in OEC pathogenesis. PMID:20181230

2010-01-01

317

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

318

Requirements for dE2F function in proliferating cells and in post-mitotic differentiating cells.  

PubMed Central

The transcription factor E2F is a target of the retinoblastoma tumor suppressor protein (pRB) and may mediate pRB regulation of S phase entry in mammalian cells. The recent identification of mutant alleles of the Drosophila E2F gene (dE2F) has shown that dE2F is required for embryogenesis. dE2F-mutant embryos lack a co-ordinated program of gene expression which accompanies S phase entry and DNA synthesis declines to levels that are barely detectable. We have investigated the role of the dE2F gene at later stages of development. dE2F is expressed in several larval tissues and is required for cell proliferation in the eye imaginal disc. Surprisingly, dE2F expression persists in post-mitotic cells of the eye disc of third-instar larvae. The loss of dE2F function in these cells causes a novel phenotype, characterized by loss of photoreceptors and abnormal rhabdomere cell morphology. These results show that dE2F is required at multiple stages of development and suggest that E2F may have an important function in post-mitotic cells in addition to its role during cell proliferation. Images PMID:8670871

Brook, A; Xie, J E; Du, W; Dyson, N

1996-01-01

319

Prostaglandin synthesis and catabolism in the gastric mucosa: studies in normal rabbits and rabbits immunized with prostaglandin E2  

SciTech Connect

Antral and fundic mucosal homogenates obtained from prostaglandin E2-immunized rabbits converted 14C-arachidonic acid to prostaglandin E2, 6-keto prostaglandin F1 alpha, prostaglandin F2 alpha, and prostaglandin D2. Percentage conversion of 14C-arachidonic acid to these prostaglandin products was not significantly different in prostaglandin E2-immunized rabbits compared with control rabbits (thyroglobulin-immunized and unimmunized rabbits combined). Synthesis of 6-keto prostaglandin F1 alpha, prostaglandin E2 and 13,14-dihydro 15-keto prostaglandin E2 from endogenous arachidonic acid after vortex mixing fundic mucosal homogenates was similar in prostaglandin E2 immunized rabbits and control rabbits. Both in prostaglandin E2-immunized rabbits and controls, 3H-prostaglandin E2 was catabolized extensively by the fundic mucosa, whereas 3H-6-keto prostaglandin F1 alpha, 3H-prostaglandin F2 alpha, and 3H-prostaglandin D2 were not catabolized to any appreciable extent. The rate of catabolism of PGs was not significantly different in prostaglandin E2-immunized rabbits and control rabbits, with the exception of prostaglandin F2 alpha which was catabolized slightly more rapidly in prostaglandin E2-immunized rabbits. These results indicate that development of gastric ulcers in prostaglandin E2-immunized rabbits is not associated with an alteration in the capacity of the gastric mucosa to synthesize or catabolize prostaglandins.

Redfern, J.S.

1988-09-01

320

Structure of the human FANCL RING-Ube2T complex reveals determinants of cognate E3-E2 selection.  

PubMed

The combination of an E2 ubiquitin-conjugating enzyme with an E3 ubiquitin-ligase is essential for ubiquitin modification of a substrate. Moreover, the pairing dictates both the substrate choice and the modification type. The molecular details of generic E3-E2 interactions are well established. Nevertheless, the determinants of selective, specific E3-E2 recognition are not understood. There are ?40 E2s and ?600 E3s giving rise to a possible ?24,000 E3-E2 pairs. Using the Fanconi Anemia pathway exclusive E3-E2 pair, FANCL-Ube2T, we report the atomic structure of the FANCL RING-Ube2T complex, revealing a specific and extensive network of additional electrostatic and hydrophobic interactions. Furthermore, we show that these specific interactions are required for selection of Ube2T over other E2s by FANCL. PMID:24389026

Hodson, Charlotte; Purkiss, Andrew; Miles, Jennifer Anne; Walden, Helen

2014-02-01

321

Physical Activity, Body Mass Index, and Prostaglandin E2 Levels in Rectal Mucosa  

Microsoft Academic Search

have been consistently shown to in- crease risk of this cancer. We investi- gated whether higher levels of leisure- time physical activity or a lower BMI was associated with lower concentra- tions of prostaglandin E2 (PGE2) in rec- tal mucosa. Methods: This study was conducted in 41 men and 22 women, 42-78 years of age, with a history of polyps,

Maria Elena Martinez; David Heddens; David L. Earnest; Cheryl L. Bogert; Denise Roe; Janine Einspahr; James R. Marshall; David S. Alberts

1999-01-01

322

Environment to Environment (E2E) Communication Systems for Collaborative Work  

E-print Network

Environment to Environment (E2E) Communication Systems for Collaborative Work Ish Rishabh irishabh with intelligent sensing of environments, to provide effective bi-directional communication which is free from, connecting environments, sentient communication. ACM Classification Keywords H5.1. Multimedia information

Reif, Rafael

323

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

324

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

E-print Network

Molecular Links between the E2 Envelope Glycoprotein and Nucleocapsid Core in Sindbis Virus Jinghua Available online 4 October 2011 Edited by R. Huber Keywords: alphavirus; cryo-reconstruction; glycoprotein for key interactions that occur between the capsid protein (CP) and transmembrane (TM) glycoproteins E1

Baker, Timothy S.

325

Silvaco ATLAS model of ESA's Gaia satellite e2v CCD91-72 pixels  

E-print Network

The Gaia satellite is a high-precision astrometry, photometry and spectroscopic ESA cornerstone mission, currently scheduled for launch in 2012. Its primary science drivers are the composition, formation and evolution of the Galaxy. Gaia will achieve its unprecedented accuracy requirements with detailed calibration and correction for CCD radiation damage and CCD geometric distortion. In this paper, the third of the series, we present our 3D Silvaco ATLAS model of the Gaia e2v CCD91-72 pixel. We publish e2v's design model predictions for the capacities of one of Gaia's pixel features, the supplementary buried channel (SBC), for the first time. Kohley et al. (2009) measured the SBC capacities of a Gaia CCD to be an order of magnitude smaller than e2v's design. We have found the SBC doping widths that yield these measured SBC capacities. The widths are systematically 2 {\\mu}m offset to the nominal widths. These offsets appear to be uncalibrated systematic offsets in e2v photolithography, which could either be du...

Seabroke, G M; Burt, D; Robbins, M S; 10.1117/12.856958

2010-01-01

326

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

327

Prostaglandin E2 Promotes Endothelial Differentiation from Bone Marrow-Derived Cells through AMPK Activation  

Microsoft Academic Search

Prostaglandin E2 (PGE2) has been reported to modulate angiogenesis, the process of new blood vessel formation, by promoting proliferation, migration and tube formation of endothelial cells. Endothelial progenitor cells are known as a subset of circulating bone marrow mononuclear cells that have the capacity to differentiate into endothelial cells. However, the mechanism underlying the stimulatory effects of PGE2 and its

Zhenjiu Zhu; Chenglai Fu; Xiaoxia Li; Yimeng Song; Chenghong Li; Minghui Zou; Youfei Guan; Yi Zhu

2011-01-01

328

Note: Completed form must be sent to Student Accounts office, MSN 2E2 or  

E-print Network

for Virginia In-state Tuition Rates," pursuant to Section 23-7-4 of the Code of Virginia. Check One Class been employed on or before the start of classes ­ an employee tuition exemption is not available to the Student Accounts Office, MSN 2E2, as soon as practicable after the employee has registered for class(es

329

Determinants of CD81 dimerization and interaction with hepatitis C virus glycoprotein E2.  

PubMed

The tetraspanin CD81 plays an essential role in diverse cellular processes. CD81 also acts as an entry receptor for HCV through an interaction between the large extracellular loop (LEL) of CD81 and HCV glycoprotein E2. The E2-CD81 interaction also results in immunomodulatory effects in vitro. In this study, we examined the relationship between the dimeric crystal structure of the CD81 LEL and intact CD81. Using random mutagenesis, amino acids were identified that abolished dimerization of recombinant LEL in regions that were important for intermonomer contacts (F150S and V146E), salt bridge formation (K124T), and intramonomer disulfide bonding (T166I, C157S, and C190R). Two monomeric LEL mutants retained the ability to bind E2, K124T, and V146E, whereas F150S, T166I, C157S, and C190R did not. Introduction of K124T, V146E, and F150S mutations in full-length CD81 did not affect its oligomerization and the effects on E2 binding were less severe than for isolated LEL. These results suggest that the LEL has a more robust structure in the intact tetraspanin with regions outside the LEL contributing to CD81 dimerization. PMID:15670777

Drummer, Heidi E; Wilson, Kirilee A; Poumbourios, Pantelis

2005-03-01

330

The production of gellan exopolysaccharide with Sphingomonas paucimobilis E2 (DSM 6314)  

Microsoft Academic Search

A new screening technique was used to isolate the bacterium Sphingomonas paucimobilis E2 (DSM 6314), which produces the exopolysaccharide gellan. The productivity was found to be about four times higher than that of the industrially used strain Auromonas elodea (ATCC 31461) it was isolated from. The polysaccharide formation was found to be predominantly growth-related.

D. Lobas; S. Schumpe; W.-D. Deckwer

1992-01-01

331

Inhibition of HCV 3a genotype entry through Host CD81 and HCV E2 antibodies  

PubMed Central

Background HCV causes acute and chronic hepatitis which can eventually lead to permanent liver damage hepatocellular carcinoma and death. HCV glycoproteins play an important role in HCV entry by binding with CD81 receptors. Hence inhibition of virus at entry step is an important target to identify antiviral drugs against HCV. Methods and result The present study elaborated the role of CD81 and HCV glycoprotein E2 in HCV entry using retroviral pseudo-particles of 3a local genotype. Our results demonstrated that HCV specific antibody E2 and host antibody CD81 showed dose- dependent inhibition of HCV entry. HCV E2 antibody showed 50% reduction at a concentration of 1.5 ± 1 ?g while CD81 exhibited 50% reduction at a concentration of 0.8 ± 1 ?g. In addition, data obtained with HCVpp were also confirmed with the infection of whole virus of HCV genotype 3a in liver cells. Conclusion Our data suggest that HCV specific E2 and host CD81 antibodies reduce HCVpp entry and full length viral particle and combination of host and HCV specific antibodies showed synergistic effect in reducing the viral titer. PMID:22074322

2011-01-01

332

Isolating a trimer intermediate in the self-assembly of E2 protein cage.  

PubMed

Understanding the self-assembly mechanism of caged proteins provides clues to develop their potential applications in nanotechnology, such as a nanoscale drug delivery system. The E2 protein from Bacillus stearothermophilus , with a virus-like caged structure, has drawn much attention for its potential application as a nanocapsule. To investigate its self-assembly process from subunits to a spherical protein cage, we truncate the C-terminus of the E2 subunit. The redesigned protein subunit shows dynamic transition between monomer and trimer, but not the integrate 60-mer. The results indicate the role of the trimer as the intermediate and building block during the self-assembly of the E2 protein cage. In combination with the molecular dynamics simulations results, we conclude that the C-terminus modulates the self-assembly of the E2 protein cage from trimer to 60-mer. This investigation elucidates the role of the intersubunit interactions in engineering other functionalities in other caged structure proteins. PMID:22320400

Peng, Tao; Lee, Hwankyu; Lim, Sierin

2012-03-12

333

THE EFFECT OF PROSTAGLANDIN E2 ON THYROIDAL SECRETION OF HORMONAL IODINE  

E-print Network

THE EFFECT OF PROSTAGLANDIN E2 ON THYROIDAL SECRETION OF HORMONAL IODINE IN THE PIG G. CABELLO A. D a significant dose-dependent reduction in hormonal iodine secretion rate was observed. These results confirm secretion of hormonal iodine in the pig.. METHODS AND RESULTS The thyroid gland in 4 pigs was isolated

Boyer, Edmond

334

Transcription Factor E2-2 Is an Essential and Specific Regulator of  

E-print Network

. The molecular control of PDC lineage specification has been poorly understood. We report that basic helix-Hopkins syndrome patients was associated with aberrant expression profile and impaired IFN response of the PDC. E2-2 directly activated multiple PDC-enriched genes, including transcription factors involved in PDC development

Symington, Lorraine S.

335

Inhibitions of histamine release and prostaglandin E2 synthesis by mangosteen, a Thai medicinal plant.  

PubMed

The fruit hull of mangosteen, Garcinia mangostana L. has been used as a Thai indigenous medicine for many years. However, its mechanism of action as a medicine has not been elucidated. The present study was undertaken to examine the effects of mangosteen extracts (100% ethanol, 70% ethanol, 40% ethanol and water) on histamine release and prostaglandin E2 synthesis. We found that the 40% ethanol extract of mangosteen inhibited IgE-mediated histamine release from RBL-2H3 cells with greater potency than the water extract of Rubus suavissimus that has been used as an anti-allergy crude drug in Japan. All extracts of mangosteen potently inhibited A23187-induced prostaglandin E2 synthesis in C6 rat glioma cells, while the water extract of Rubus suavissimus had no effect. The 40% ethanol extract of mangosteen inhibited the prostaglandin E2 synthesis in a concentration-dependent manner with relatively lower concentrations than the histamine release. In addition, passive cutaneous anaphylaxis (PCA) reactions in rats were significantly inhibited by this ethanol extract as well as by the water extract of Rubus suavissimus. These results suggest that the 40% ethanol extract of mangosteen has potent inhibitory activities of both histamine release and prostaglandin E2 synthesis. PMID:12230104

Nakatani, Keigo; Atsumi, Masanori; Arakawa, Tsutomu; Oosawa, Kenji; Shimura, Susumu; Nakahata, Norimichi; Ohizumi, Yasushi

2002-09-01

336

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 sÀ1 using a high nature of Kevlar-49 fabric results in large displacements and shape changes during tests. Noncontacting

Mobasher, Barzin

337

Prostaglandin E2 promotes degranulation-independent release of MCP-1 from mast cells  

Microsoft Academic Search

Mast cells (MCs) are common compo- nents of inflammatory infiltrates and a source of proangiogenic factors. Inflammation is often ac- companied by vascular changes. However, little is known about modulation of MC-derived proangio- genic factors during inflammation. In this study, we evaluated the effects of the proinflammatory medi- ator prostaglandin E2 (PGE2) on MC expression and release of proangiogenic factors.

Takayuki Nakayama; Noriko Mutsuga; Lei Yao; Giovanna Tosato

2005-01-01

338

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

339

Ventromedial Preoptic Prostaglandin E2 Activates Fever-Producing Autonomic Pathways  

Microsoft Academic Search

Fever is thought to be initiated by pyrogenic cytokines inducing the production of prostaglandin E2 (PGE2) in the preoptic area (POA); PGE2 may act as a paracrine mediator that stimulates the neural pathways that raise body temperature. This essential role for prostaglandins in feverfirst was proposed 25 years ago, but the specific preoptic cell groups at which PGE2 acts and

Thomas E. Scammell; Joel K. Elmquist; John D. Griffin; Clifford B. Saper

340

Possible Alzheimer’s Disease in an Apolipoprotein E2 Homozygote  

PubMed Central

The objective of this study was to describe a case of Alzheimer’s disease in an ApoE ?2/?2 homozygote. ApoE ?2/?2 is the rarest of the apolipoprotein E genotypes, representing only 1.4% of the population. There is only one case reported in the literature of a nonagenarian with minimal cognitive changes whose brain showed AD pathology on postmortem study. Here we report an 87-year-old ApoE ?2/?2 female who meets clinical criteria for Alzheimer’s disease, with confirmation from neuropsychological testing and PET scan. Clinical course is typical for Alzheimer’s disease with decline on the Mini-Mental Status Examination from a score of 25 to 19 over 3.5 years. The patient is currently treated with donepezil and memantine. In conclusion, a clinically confirmed case of Alzheimer’s disease is rare in Apo E2 homozygotes but can occur. PMID:19158419

Ignatov, Ignat; Belden, Christine; Jacobson, Sandra; Connor, Donald; Sabbagh, Marwan N.

2010-01-01

341

DOE Hydrogen Program FY 2004 Progress Report II.E.2 Photoelectrochemical Hydrogen Production  

E-print Network

DOE Hydrogen Program FY 2004 Progress Report II.E.2 Photoelectrochemical Hydrogen Production Eric L DOE in the development of technology to produce hydrogen using solar energy to photoelectrochemically split water · Develop cost-effective materials systems for efficient photoelectrochemical (PEC) hydrogen

342

Transforming Healthcare Delivery Systems E2 STEM July 2013 www.purdue.edu/discoverypark  

E-print Network

academic research to challenges in healthcare. The intent is to resolve issues by providing access to newINITIATIVE IMPACT NEED Transforming Healthcare Delivery Systems E2 STEM July 2013 www.S. healthcare industry continues to face a number of challenges. Many treatments do not reach patients who may

Ginzel, Matthew

343

26 CFR 301.6231(e)-2 - Judicial decision not a bar to certain adjustments.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Judicial decision not a bar to certain adjustments. 301.6231...6231(e)-2 Judicial decision not a bar to certain adjustments. (a) In general...attributable to nonpartnership items shall not be a bar to further proceedings with...

2010-04-01

344

The E2F transcription factors regulate tumor development and metastasis in a mouse model of metastatic breast cancer.  

PubMed

While the E2F transcription factors (E2Fs) have a clearly defined role in cell cycle control, recent work has uncovered new functions. Using genomic signature methods, we predicted a role for the activator E2F transcription factors in the mouse mammary tumor virus (MMTV)-polyomavirus middle T oncoprotein (PyMT) mouse model of metastatic breast cancer. To genetically test the hypothesis that the E2Fs function to regulate tumor development and metastasis, we interbred MMTV-PyMT mice with E2F1, E2F2, or E2F3 knockout mice. With the ablation of individual E2Fs, we noted alterations of tumor latency, histology, and vasculature. Interestingly, we noted striking reductions in metastatic capacity and in the number of circulating tumor cells in both the E2F1 and E2F2 knockout backgrounds. Investigating E2F target genes that mediate metastasis, we found that E2F loss led to decreased levels of vascular endothelial growth factor (Vegfa), Bmp4, Cyr61, Nupr1, Plod 2, P4ha1, Adamts1, Lgals3, and Angpt2. These gene expression changes indicate that the E2Fs control the expression of genes critical to angiogenesis, the remodeling of the extracellular matrix, tumor cell survival, and tumor cell interactions with vascular endothelial cells that facilitate metastasis to the lungs. Taken together, these results reveal that the E2F transcription factors play key roles in mediating tumor development and metastasis in addition to their well-characterized roles in cell cycle control. PMID:24934442

Hollern, Daniel P; Honeysett, Jordan; Cardiff, Robert D; Andrechek, Eran R

2014-09-01

345

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

346

E2F1 downregulation by arsenic trioxide in lung adenocarcinoma.  

PubMed

Lung cancer is one of the most common cancers worldwide. Arsenic trioxide (ATO) has been approved by the US Food and Drug Administration for the treatment of acute promyelocytic leukemia. Nonetheless preliminary data have suggested potential activity of ATO in solid tumors including lung cancer. This study aimed to examine the underlying mechanisms of ATO in the treatment of lung adenocarcinoma. Using a panel of 7 lung adenocarcinoma cell lines, the effects of ATO treatment on cell viability, expression of E2F1 and its downstream targets, phosphatidylserine externalization, mitochondrial membrane depolarization and alteration of apoptotic/anti-apoptotic factors were studied. Tumor growth inhibition in vivo was investigated using a nude mouse xenograft model. ATO decreased cell viability with clinically achievable concentrations (8 µM) in all cell lines investigated. This was accompanied by reduced expression of E2F1, cyclin A2, skp2, c-myc, thymidine kinase and ribonucleotide reductase M1, while p-c-Jun was upregulated. Cell viability was significantly decreased with E2F1 knockdown. Treatment with ATO resulted in phosphatidylserine externalization in H23 cells and mitochondrial membrane depolarization in all cell lines, associated with truncation of Bid, downregulation of Bcl-2, upregulation of Bax and Bak, caspase-9 and -3 activation and PARP cleavage. Using the H358 xenograft model, the tumor growth was suppressed in the ATO treatment group during 8 days of treatment, associated with downregulation of E2F1 and upregulation of truncated Bid and cleaved caspase-3. In conclusion, ATO has potent in vitro and in vivo activity in lung adenocarcinoma, partially mediated through E2F1 downregulation and apoptosis. PMID:25174355

Lam, Sze-Kwan; Li, Yuan-Yuan; Zheng, Chun-Yan; Leung, Leanne Lee; Ho, James Chung-Man

2014-11-01

347

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

348

Assessment of the role of in situ generated (E)-2,4-diene-valproic acid in the toxicity of valproic acid and (E)-2-ene-valproic acid in sandwich-cultured rat hepatocytes  

SciTech Connect

Valproic acid (VPA) undergoes cytochrome P450-mediated desaturation to form 4-ene-VPA, which subsequently yields (E)-2,4-diene-VPA by ?-oxidation. Another biotransformation pathway involves ?-oxidation of VPA to form (E)-2-ene-VPA, which also generates (E)-2,4-diene-VPA by cytochrome P450-mediated desaturation. Although the synthetic form of (E)-2,4-diene-VPA is more hepatotoxic than VPA as shown in various experimental models, there is no conclusive evidence to implicate the in situ generated (E)-2,4-diene-VPA in VPA hepatotoxicity. The present study investigated the effects of modulating the in situ formation of (E)-2,4-diene-VPA on markers of oxidative stress (formation of 2?,7?-dichlorofluorescein; DCF), steatosis (accumulation of BODIPY 558/568 C{sub 12}), necrosis (release of lactate dehydrogenase; LDH), and on cellular total glutathione (GSH) levels in sandwich-cultured rat hepatocytes treated with VPA or (E)-2-ene-VPA. Treatment with either of these chemicals alone increased each of the toxicity endpoints. In VPA-treated hepatocytes, (E)-2,4-diene-VPA was detected only at trace levels, even after phenobarbital (PB) pretreatment and there was no effect on the toxicity of VPA. Furthermore, pretreatment with a cytochrome P450 enzyme inhibitor, 1-aminobenzotriazole (1-ABT), did not influence the extent of VPA toxicity in both PB-pretreated and vehicle-pretreated hepatocytes. However, in (E)-2-ene-VPA-treated hepatocytes, PB pretreatment greatly enhanced the levels of (E)-2,4-diene-VPA and this was accompanied by a further enhancement of the effects of (E)-2-ene-VPA on DCF formation, BODIPY accumulation, LDH release, and GSH depletion. Pretreatment with 1-ABT reduced the concentrations of (E)-2,4-diene-VPA and the extent of (E)-2-ene-VPA toxicity; however, this occurred in PB-pretreated hepatocytes, but not in control hepatocytes. In conclusion, in situ generated (E)-2,4-diene-VPA is not responsible for the hepatocyte toxicity of VPA, whereas it contributes to the toxicity of (E)-2-ene-VPA in PB-pretreated rat hepatocytes. -- Highlights: ? (E)-2,4-diene-valproic acid is a reactive and toxic metabolite of valproic acid (VPA). ? In situ, this metabolite is not responsible for VPA toxicity in rat hepatocytes. ? This metabolite enhances (E)-2-ene-VPA toxicity in PB-pretreated hepatocytes.

Surendradoss, Jayakumar; Chang, Thomas K.H.; Abbott, Frank S., E-mail: frank.abbott@ubc.ca

2012-11-01

349

An integrated bioinformatics approach identifies elevated cyclin E2 expression and E2F activity as distinct features of tamoxifen resistant breast tumors.  

PubMed

Approximately half of estrogen receptor (ER) positive breast tumors will fail to respond to endocrine therapy. Here we used an integrative bioinformatics approach to analyze three gene expression profiling data sets from breast tumors in an attempt to uncover underlying mechanisms contributing to the development of resistance and potential therapeutic strategies to counteract these mechanisms. Genes that are differentially expressed in tamoxifen resistant vs. sensitive breast tumors were identified from three different publically available microarray datasets. These differentially expressed (DE) genes were analyzed using gene function and gene set enrichment and examined in intrinsic subtypes of breast tumors. The Connectivity Map analysis was utilized to link gene expression profiles of tamoxifen resistant tumors to small molecules and validation studies were carried out in a tamoxifen resistant cell line. Despite little overlap in genes that are differentially expressed in tamoxifen resistant vs. sensitive tumors, a high degree of functional similarity was observed among the three datasets. Tamoxifen resistant tumors displayed enriched expression of genes related to cell cycle and proliferation, as well as elevated activity of E2F transcription factors, and were highly correlated with a Luminal intrinsic subtype. A number of small molecules, including phenothiazines, were found that induced a gene signature in breast cancer cell lines opposite to that found in tamoxifen resistant vs. sensitive tumors and the ability of phenothiazines to down-regulate cyclin E2 and inhibit proliferation of tamoxifen resistant breast cancer cells was validated. Our findings demonstrate that an integrated bioinformatics approach to analyze gene expression profiles from multiple breast tumor datasets can identify important biological pathways and potentially novel therapeutic options for tamoxifen-resistant breast cancers. PMID:21789246

Huang, Lei; Zhao, Shuangping; Frasor, Jonna M; Dai, Yang

2011-01-01

350

Interaction of the Most Membranotropic Region of the HCV E2 Envelope Glycoprotein with Membranes. Biophysical Characterization  

PubMed Central

The previously identified membrane-active regions of the hepatitis C virus (HCV) E1 and E2 envelope glycoproteins led us to identify different segments that might be implicated in viral membrane fusion, membrane interaction, and/or protein-protein binding. HCV E2 glycoprotein contains one of the most membranotropic segments, segment 603–634, which has been implicated in CD81 binding, E1/E2 and E2/E2 dimerization, and membrane interaction. Through a series of complementary experiments, we have carried out a study of the binding and interaction with the lipid bilayer of a peptide corresponding to segment 603–634, peptide E2FP, as well as the structural changes induced by membrane binding that take place in both the peptide and the phospholipid molecules. Here, we demonstrate that peptide E2FP binds to and interacts with phospholipid model membranes, modulates the polymorphic phase behavior of membrane phospholipids, is localized in a shallow position in the membrane, and is probably oligomerized in the presence of membranes. These data support the role of E2FP in HCV-mediated membrane fusion, and sustain the notion that this segment of the E2 envelope glycoprotein, together with other segments of E2 and E1 glycoproteins, provides the driving force for the merging of the viral and target cell membranes. PMID:18339752

Pérez-Berná, Ana J.; Guillén, Jaime; Moreno, Miguel R.; Gómez-Sánchez, Ana I.; Pabst, George; Laggner, Peter; Villalaín, José

2008-01-01

351

Topical application of 17?-estradiol (E2) improves skin flap survival through activation of endothelial nitric oxide synthase in rats.  

PubMed

This study investigates the influence of 17?-estradiol (E2) on nitric oxide (NO) production in endothelial cell cultures and the effect of topical E2 on the survival of skin flap transplants in a rat model. Human umbilical vein endothelial cells were treated with three different E2 concentrations and nitrite (NO2) concentrations, as well as endothelial nitric oxide synthase (eNOS) protein expressions were analyzed. In vivo, random-pattern skin flaps were raised in female Wistar rats 14 days following ovariectomy and treated with placebo ointment (group 1), E2 as gel (group 2), and E2 via plaster (group 3). Flap perfusion, survival, and NO2 levels were measured on postoperative day 7. In vitro, E2 treatment increased NO2 concentration in cell supernatant and eNOS expression in cell lysates (p?E2 treated (gel and plaster groups) demonstrated significantly increased skin flap survival compared to the placebo group (p?E2 plaster-treated animals exhibited higher NO2 blood levels than placebo (p?E2 increases NO production in endothelial cells via eNOS activation. Topical E2 application can significantly increase survival of ischemically challenged skin flaps in a rat model and may augment wound healing in other ischemic situations via activation of NO production. PMID:22805596

Shafighi, Maziar; Fathi, Ali R; Brun, Claudio; Huemer, Georg M; Wirth, Raphael; Hunger, Robert; Banic, Andrej; Constantinescu, Mihai A

2012-01-01

352

Role of an adenovirus E2 promoter binding factor in E1A-mediated coordinate gene control.  

PubMed Central

A product of the adenovirus gene E1A is responsible for the stimulation of transcription from six viral promoters as well as at least two cellular promoters. We have detected a HeLa cell factor, termed E2 promoter binding factor (E2F), that appears to mediate the transcriptional stimulation of the viral E2 promoter. Competition experiments revealed that E2F did not recognize and bind to the E1B, E3, E4, or major late promoter sequences. Furthermore, three additional promoters stimulated by E1A, heat shock protein 70, beta-globin, and early simian virus 40, do not bind E2F. In contrast, the factor does recognize sequences in the E1A enhancer, and within the E1A enhancer are duplicated binding sites for E2F. Finally, a single E2F binding site from the E1A enhancer can confer increased transcription to a mouse beta-globin promoter, dependent on the action of the E1A gene product. This stimulation requires binding of E2F since methylation of the binding site, which blocks binding in vitro, reduces transcription stimulation in vivo. We, therefore, conclude that E2F is likely to be responsible for the E1A-mediated stimulation of the E1A gene as well as the E2 gene but is not involved in the activation of the other E1A-inducible promoters. Images PMID:2951737

Kovesdi, I; Reichel, R; Nevins, J R

1987-01-01

353

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

354

Active repression and E2F inhibition by pRB are biochemically distinguishable  

PubMed Central

To understand mechanistically how pRB represses transcription, we used a reconstituted transcription assay and compared pRB activity on naked versus chromatin templates. Surprisingly, when pRB was directly recruited to a naked template, no transcriptional repression was observed. However, we observed active repression when the same promoter was assembled into chromatin. Histone deacetylases do not appear to play a role in this observed repression. Further experiments showed repression could occur after preinitiation complex assembly, in contrast with pRB inhibition of E2F, suggesting discrete mechanisms by which pRB directly inhibits an activator such as E2F or actively represses proximally bound transcription factors. PMID:11230147

Ross, John F.; Näär, Anders; Cam, Hieu; Gregory, Richard; Dynlacht, Brian David

2001-01-01

355

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

356

Id2-Mediated Inhibition of E2A Represses Memory CD8+ T Cell Differentiation  

PubMed Central

The transcription factor inhibitor of DNA binding (Id)2 modulates T cell fate decisions, but the molecular mechanism underpinning this regulation is unclear. In this study we show that loss of Id2 cripples effector differentiation and instead programs CD8+ T cells to adopt a memory fate with increased Eomesodermin and Tcf7 expression. We demonstrate that Id2 restrains CD8+ T cell memory differentiation by inhibiting E2A-mediated direct activation of Tcf7 and that Id2 expression level mirrors T cell memory recall capacity. As a result of the defective effector differentiation, Id2-deficient CD8+ T cells fail to induce sufficient Tbx21 expression to generate short-lived effector CD8+ T cells. Our findings reveal that the Id2/E2A axis orchestrates T cell differentiation through the induction or repression of downstream transcription factors essential for effector and memory T cell differentiation. PMID:23536629

Masson, Frederick; Minnich, Martina; Olshansky, Moshe; Bilic, Ivan; Mount, Adele M.; Kallies, Axel; Speed, Terence P.; Busslinger, Meinrad; Nutt, Stephen L.

2013-01-01

357

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

358

E1 and E2 contributions to the L3 resonance line shape in antiferromagnetic holmium  

E-print Network

A detailed study of the angular, energy and polarization dependences of the electric dipolar (E1: 2p->5d) and quadrupolar (E2: 2p->4f) contributions to the x-ray scattering cross-section is presented for holmium in its basal plane spiral antiferromagnetic phase at the L3 edge. The corresponding E1 and E2 scattering factors have been extracted from fits to the experimental energy line shapes taking into account for the first time a split dipole resonance. Using the imaginary part of the resonant scattering factors to retrieve the XMCD spectrum, we find qualitative agreement with the dichroic spectrum measured in transmission through a holmium foil.

Bouchenoire, L; Brown, S D; Strange, P; Wood, T; Thompson, P; Fort, D; Fernandez-Rodriguez, J

2009-01-01

359

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

360

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

361

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

362

Distance enhancing codes for E2PRML: performance comparison using spinstand data  

Microsoft Academic Search

Two new RLL encoding schemes for the E2PR4 recording channel are analyzed experimentally. These codes, employing a d=0 run length constraint, simplify the detector complexity while achieving a higher code rate than the traditional (1,7) recording code. They also maintain the same minimum squared distance, d2=10, as the (1,7) code. Using spin-stand data from an MR head, the new codes

Steven G. McCarthy; Zachary A. Keirn

1997-01-01

363

Labor induction with intravaginal misoprostol versus intracervical prostaglandin E 2 gel (Prepidil gel): Randomized comparison  

Microsoft Academic Search

OBJECTIVE: Our purpose was to compare the safety and efficacy of intravaginal prostaglandin E1, misoprostol, with that of intracervical prostaglandin E2 (Prepidil gel) for labor induction.STUDY DESIGN: One hundred three patients with an indication for induction of labor were randomly assigned to induction with prostaglandin E1, 50 ?g intravaginally, or with Prepidil gel, 0.5 mg intracervically, every 4 hours until

Frank J. Chuck; B. Joyce Huffaker

1995-01-01

364

Independent binding of the retinoblastoma protein and p107 to the transcription factor E2F  

Microsoft Academic Search

THE cellular protein p107 and the retinoblastoma protein (pRB) have many features in common. Most strikingly, they contain homologous protein domains that mediate interaction with the oncoproteins of several small DNA tumour viruses, including adenovirus El A and SV40 large-T antigen1-9. In cells that do not contain these viral oncoproteins, pRB interacts with the cellular transcription factor E2F (refs 10-12)

Liang Cao; Barbara Faha; Marlene Dembski; Li-Huei Tsai; Ed Harlow; Nicholas Dyson

1992-01-01

365

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

366

Anabolic Effect of Prostaglandin E 2 in Bone Is not Dependent on Pituitary Hormones in Rats  

Microsoft Academic Search

.   Prostaglandin E2 (PGE2) is an anabolic agent of bone in vivo but the mechanism of its action still remains unclear. The aim of this study was to determine whether the effect of PGE2 on skeleton is mediated by pituitary hormones. Forty female, Sprague-Dawley rats were divided into four groups: baseline\\u000a control (basal), age-matched intact control (CON), hypophysectomy (HX), and

M. M. Chen; J. K. Yeh; J. F. Aloia

1998-01-01

367

Prostaglandin E 2 EP4 agonist (ONO4819) accelerates BMP-induced osteoblastic differentiation  

Microsoft Academic Search

Bone morphogenetic proteins (BMPs) were originally isolated based on their ability to induce ectopic cartilage and bone formation. The agents to promote the local bone formation with BMP would be beneficial to promote bone repair and to shorten the treatment period. For this purpose, we have examined ONO-4819, which is a prostaglandin (PG) E2 EP4 receptor selective agonist (EP4A), as

Keisuke Nakagawa; Yuuki Imai; Yoichi Ohta; Kunio Takaoka

2007-01-01

368

Prostaglandin E2 in the Vitreous Body of the Normal Rabbit Eye and after Ocular Trauma  

Microsoft Academic Search

Rabbit eyes were enucleated and frozen in liquid nitrogen. The vitreous was removed and analyzed for prostaglandin E2 (PGE2). The mean level ( ± SEM) of PGE2 in the anterior as well as in the posterior vitreous was 0.09 ± 0.016 ng\\/ml (n = 12 rabbits). Animals pretreated with indomethacin 15 min before death, in order to prevent the formation

J. L. van Delft; N. J. van Haeringen; V. M. Bodelier; E. R. Barthen; J. A. Oosterhuis

1991-01-01

369

A new non-Hermitian E2-quasi-exactly solvable model  

E-print Network

We construct a previously unknown $E_2$-quasi-exactly solvable non-Hermitian model whose eigenfunctions involve weakly orthogonal polynomials obeying three-term recurrence relations that factorize beyond the quantization level. The model becomes Hermitian when one of its two parameters is fixed to a specific value. We analyze the double scaling limit of this model leading to the complex Mathieu equation. The norms, Stieltjes measures and moment functionals are evaluated for some concrete values of one of the two parameters.

Andreas Fring

2014-12-08

370

Inhibition of the bovine papillomavirus E2 protein activity by peptide nucleic acid  

Microsoft Academic Search

The bovine papillomavirus type-1 E2 protein is the master regulator of the papillomavirus transcription and replication, the activity of which is regulated through sequence-specific DNA binding. Peptide nucleic acid (PNA) is a nucleic acid analogue, which associates with high affinity to complementary DNA, RNA or PNA, yielding in formation of stable complexes. The potential use of PNA as a sequence-specific

Reet Kurg; Ülo Langel; Mart Ustav

2000-01-01

371

Phosphatidylinositol 3Kinase Couples the Interleukin2 Receptor to the Cell Cycle Regulator E2F  

Microsoft Academic Search

Cell cycle progression initiated by interleukin-2 (IL-2) in T cells is critical for lymphoproliferation and an immune response. Phosphatidyl inositol 3-kinase (PI3K) is activated by IL-2. However, nuclear targets for PI3K are not known. Here we identify the cell cycle regulator E2F as an IL-2 target in T lymphocytes and PI3K as the critical signaling pathway. We eliminate both Stat5

Paul Brennan; Jane W Babbage; Boudewijn M. T Burgering; Bernd Groner; Karin Reif; Doreen A Cantrell

1997-01-01

372

Prostaglandin E2 Suppresses Bacterial Killing in Alveolar Macrophages by Inhibiting NADPH Oxidase  

Microsoft Academic Search

Prostaglandin E2 (PGE2) is a potent lipid mediator that effects changes in cell functions through ligation of four distinct G protein- coupled E prostanoid (EP) receptors (EP1-EP4). PGE2 inhibits bacte- rial killing and reactive oxygen intermediate (ROI) production by alveolar macrophages (AMs), although little is known about the operative molecular mechanisms. The aims of this study were to evaluate the

Carlos H. Serezani; Jooho Chung; Megan N. Ballinger; Bethany B. Moore; David M. Aronoff; Marc Peters-Golden

2007-01-01

373

Xylose metabolism in the anaerobic fungus Piromyces sp. strain E2 follows the bacterial pathway  

Microsoft Academic Search

The anaerobic fungus Piromyces sp. strain E2 metabolizes xylose via xylose isomerase and d-xylulokinase as was shown by enzymatic and molecular analyses. This resembles the situation in bacteria. The clones encoding the two enzymes were obtained from a cDNA library. The xylose isomerase gene sequence is the first gene of this type reported for a fungus. Northern blot analysis revealed

Harry R. Harhangi; Anna S. Akhmanova; Roul Emmens; Chris van der Drift; Johannes P. van Dijken; Mike S. M. Jetten; Jack T. Pronk

2003-01-01

374

Improvements of the astro-E2 hard X-ray detector (HXD-II)  

Microsoft Academic Search

We summarize significant improvements which have been achieved in the development of Astro-E2 Hard X-ray Detector (HXD-II). An expanded energy range and better energy resolution have been achieved from progresses in device materials and redesigning of the front-end electronics. An improved estimation for the detector background in orbit has also been conducted based upon results from our proton irradiation experiment.

M. Kokubun; K. Abe; Y. Ezoe; Y. Fukazawa; S. Hong; H. Inoue; T. Itoh; T. Kamae; D. Kasama; M. Kawaharada; N. Kawano; K. Kawashima; S. Kawasoe; Y. Kobayashi; J. Kotoku; M. Kouda; A. Kubota; G. M. Madejski; K. Makishima; T. Mitani; H. Miyasaka; R. Miyawaki; K. Mori; M. Mori; T. Murakami; M. M. Murashima; K. Nakazawa; H. Niko; M. Nomachi; M. Ohno; Y. Okada; K. Oonuki; G. Sato; M. Suzuki; H. Takahashi; I. Takahashi; T. Takahashi; K. Tamura; T. Tanaka; M. Tashiro; Y. Terada; S. Tominaga; S. Watanabe; K. Yamaoka; T. Yanagida; D. Yonetoku

2004-01-01

375

Prostaglandin-E2 Is a Potent Inhibitor of Human Interleukin 12 Production  

Microsoft Academic Search

Summary During human immunodeficiency virus infection and allergic diseases, characterized by a dominant T helper (Th) 2 response, overproduction of prostaglandin E2 (PGE2) is observed. In this paper we studied the effect of PGE2 on interleukin (IL)-12 synthesis, because this cytokine has been described to be essential in induction of Thl responses. IL-12 synthesis was induced in monocytes that were

Leonie C. M. Boeije; Ruud J. T. Smeenk; John Wijdenes; Lucien A. Aarden; Boulevard A-Fleming

1995-01-01

376

Patients with adenomatous polyps and carcinomas have increased colonic mucosal prostaglandin E2  

Microsoft Academic Search

Colorectal carcinoma in humans and animal models is associated with increased synthesis of prostaglandin E2 (PGE2). PGE2 synthesis was measured in normal and neoplastic human colorectal mucosa to investigate its role in the adenoma-carcinoma sequence. Paired mucosal biopsy specimens for PGE2 synthesis and histological examination were obtained during 39 diagnostic colonoscopies. Twelve control patients in whom colonoscopies and histology were

S Pugh; G A Thomas

1994-01-01

377

Effect of flow on prostaglandin E2 and inositol trisphosphate levels in osteoblasts  

Microsoft Academic Search

REICH,KATHLEEN M., ANDJOHN A. FRANGOS. Effectofflow on prostaglandin E2 and inositol trisphosphate levels in osteo- blasts. Am. J. Physiol. 261 (Cell Physiol. 30): C428-C432, 1991.-Osteoblasts in culture respond to mechanical strains. Fluid flow has been shown to increase intracellular adenosine 3 ' ,5 ' -cyclic monophosphate levels in cultured osteoblasts, and this response is mediated by prostaglandin synthesis. The signal

KATHLEEN M. REICH; JOHN A. FRANGOS

1991-01-01

378

Cyclosporin A inhibits prostaglandin E2 formation by rat mesangial cells in culture  

Microsoft Academic Search

Cyclosporin A inhibits prostaglandin E2 formation by rat mesangial cells in culture. A reversible reduction in glomerular filtration rate (GFR) is a frequent side effect in patients treated with the immunosuppressant cyclosporin A (CsA). The pathophysiology of acute CsA nephrotoxicity, however, is unclear. Since eicosanoids are local mediators of glomerular hemodynamics, they might be involved in CsA induced changes in

Rolf A K Stahl; Stephen Adler; Patricia J Baker; Richard J Johnson; Yi-Pu Chen; Pam Pritzl; William G Couser; William Causer

1989-01-01

379

Early B Cell Factor Promotes B Lymphopoiesis with Reduced Interleukin 7 Responsiveness in the Absence of E2A  

Microsoft Academic Search

The basic helix-loop-helix transcription factors encoded by the E2A gene function at the apex of a transcriptional hierarchy involving E2A, early B cell factor (EBF), and Pax5, which is essen- tial for B lymphopoiesis. In committed B lineage progenitors, E2A proteins have also been shown to regulate many lineage-associated genes. Herein, we demonstrate that the block in B lymphopoiesis imposed

Christopher S. Seet; Rachel L. Brumbaugh; Barbara L. Kee

2004-01-01

380

Expression of the surface glycoprotein E2 of Bovine viral diarrhea virus by recombinant vesicular stomatitis virus  

Microsoft Academic Search

This study analysed the transport behaviour of the glycoprotein E2 of Bovine viral diarrhea virus (BVDV) expressed from recombinant vesicular stomatitis virus (rVSV). E2 protein was found to be retained at an intracellular compartment. A chimeric protein containing the membrane anchor and cytoplasmic tail of the VSV G protein, E2-G(MT), was transported to the cell surface. Only the latter protein

Wiebke Kohl; Andrea Grone; Volker Moennig; Georg Herrler

2007-01-01

381

Generation and efficacy evaluation of a recombinant adenovirus expressing the E2 protein of classical swine fever virus  

Microsoft Academic Search

Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), which causes significant economic losses to the pig industry worldwide. The E2 glycoprotein of CSFV is the main target for neutralizing antibodies. This study was aimed to develop a recombinant human adenovirus type 5 expressing the CSFV E2 gene (rAdV-E2) and evaluate its efficacy in rabbits

Yuan Sun; Da-Fei Liu; Yu-Fei Wang; Bing-Bing Liang; Dan Cheng; Na Li; Qiao-Fen Qi; Qing-Hu Zhu; Hua-Ji Qiu

2010-01-01

382

Nat Cell Biol . Author manuscript The CDK4-pRB-E2F1 pathway controls insulin secretion  

E-print Network

in / -cells. Finally, we demonstrate that CDK4 is activated by glucose through the insulin pathway,E2f1 evidence that theKir6.2 CDK4-pRB-E2F1 regulatory pathway is involved in glucose homeostasis, defining a newNat Cell Biol . Author manuscript Page /1 11 The CDK4-pRB-E2F1 pathway controls insulin secretion

Paris-Sud XI, Université de

383

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

384

Unbiased Analysis of RB-mediated Transcriptional Repression Identifies Novel Targets and Distinctions from E2F Action1  

Microsoft Academic Search

The retinoblastoma tumor suppressor, RB, is thought to inhibit cell cycle progression through transcriptional repression. E2F-regulated genes have been viewed as presumptive targets of RB-mediated repression. However, we found that specific E2F targets were not regulated in a consistent manner by the action of a RB allele that is refractory to cyclin-dependent kinase\\/cyclin-mediated phosphorylation (PSM-RB) when compared with E2F2 overproduction.

Michael P. Markey; Steven P. Angus; Matthew W. Strobeck; Sarah L. Williams; Ranjaka W. Gunawardena; Bruce J. Aronow; Erik S. Knudsen

2002-01-01

385

hSNF5 Is Required for Human Papillomavirus E2Driven Transcriptional Activation and DNA Replication  

Microsoft Academic Search

Objective: To determine the participation of the SWI\\/SNF complex in the transcription and replication of human papillomavirus (HPV) E2 protein. Method: We checked the interaction between hSNF5 and HPV E2 through glutathione S-transferase (GST) pull-down and coimmunoprecipitation assays. The transcriptional activation of E2 was analyzed by reporter assay and the level of HPV DNA replication was determined by a transient

Seho Cha; Taegun Seo

2011-01-01

386

Contrle de la libration de la GH par le GRF et la prostaglandine E2 dans un systme de prifusion  

E-print Network

Contrôle de la libération de la GH par le GRF et la prostaglandine E2 dans un système de périfusion and prostaglandin E2 in superfused rat pituitary cells. Using superfused rat pituitary cells we showed that the growth hormone-releasing fac- tor (GRF) and prostaglandin E2 (PGE2) increased growth hormone (GH

Boyer, Edmond

387

DDB, a Putative DNA Repair Protein, Can Function as a Transcriptional Partner of E2F1  

Microsoft Academic Search

The transcription factor E2F1 is believed to be involved in the regulated expression of the DNA replication genes. To gain insights into the transcriptional activation function of E2F1, we looked for proteins in HeLa nuclear extracts that bind to the activation domain of E2F1. Here we show that DDB, a putative DNA repair protein, associates with the activation domain of

STEVEN HAYES; PAVEL SHIYANOV; XIAOQUN CHEN; PRADIP RAYCHAUDHURI

388

A novel E2 box-GATA element modulates Cdc6 transcription during human cells polyploidization.  

PubMed

Cdc6 is a key regulator of the strict alternation of S and M phases during the mitotic cell cycle. In mammalian and plant cells that physiologically become polyploid, cdc6 is transcriptionally and post-translationally regulated. We have recently reported that Cdc6 levels are maintained in megakaryoblastic HEL cells, but severely downregulated by ectopic expression of transcriptional repressor Drosophila melanogaster escargot. Here, we show that cdc6 promoter activity is upregulated during megakaryocytic differentiation of HEL endoreplicating cells, and that Escargot interferes with such activation. Transactivation experiments showed that a 1.7 kb region located at 2800 upstream cdc6 transcription initiation site behaved as a potent enhancer in endoreplicating cells only. This activity was mainly dependent on a novel cis-regulatory element composed by an E2 box overlapping a GATA motif. Ectopic Escargot could bind this regulatory element in vitro and endogenous GATA-1 and E2A formed specific complexes in megakaryoblastic cells as well as in primary megakaryocytes. Chromatin Immunoprecipitation analysis revealed that both transcription factors were occupying the E2 box/GATA site in vivo. Altogether, these data suggest that cdc6 expression could be actively maintained during megakaryocytic differentiation through transcriptional mechanisms involving specific cis- and trans-regulatory elements. PMID:15590906

Vilaboa, Nuria; Bermejo, Rodrigo; Martinez, Pilar; Bornstein, Rafael; Calés, Carmela

2004-01-01

389

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

390

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

391

CMIP5 historical simulations (1850-2012) with GISS ModelE2  

NASA Astrophysics Data System (ADS)

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, 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

392

Overexpression of Cohesion Establishment Factor DSCC1 through E2F in Colorectal Cancer  

PubMed Central

Ctf18-replication factor C complex including Dscc1 (DNA replication and sister chromatid cohesion 1) is implicated in sister chromatid cohesion, DNA replication, and genome stability in S. cerevisiae and C. elegans. We previously performed gene expression profiling in primary colorectal cancer cells in order to identify novel molecular targets for the treatment of colorectal cancer. A feature of the cancer-associated transcriptional signature revealed from this effort is the elevated expression of the proto-oncogene DSCC1. Here, we have interrogated the molecular basis for deviant expression of human DSCC1 in colorectal cancer and its ability to promote survival of cancer cells. Quantitative PCR and immunohistochemical analyses corroborated that the expression level of DSCC1 is elevated in 60–70% of colorectal tumors compared to their matched noncancerous colonic mucosa. An in silico evaluation of the presumptive DSCC1 promoter region for consensus DNA transcriptional regulatory elements revealed a potential role for the E2F family of DNA-binding proteins in controlling DSCC1 expression. RNAi-mediated reduction of E2F1 reduced expression of DSCC1 in colorectal cancer cells. Gain- and loss-of-function experiments demonstrated that DSCC1 is involved in the viability of cancer cells in response to genotoxic stimuli. We reveal that E2F-dependent expression of DSCC1 confers anti-apoptotic properties in colorectal cancer cells, and that its suppression may be a useful option for the treatment of colorectal cancer. PMID:24465681

Yamaguchi, Kiyoshi; Yamaguchi, Rui; Takahashi, Norihiko; Ikenoue, Tsuneo; Fujii, Tomoaki; Shinozaki, Masaru; Tsurita, Giichiro; Hata, Keisuke; Niida, Atsushi; Imoto, Seiya; Miyano, Satoru; Nakamura, Yusuke; Furukawa, Yoichi

2014-01-01

393

Altered T-dependent antigen responses and development of autoimmune symptoms in mice lacking E2A in T lymphocytes  

PubMed Central

E2A has been shown to be an important transcription factor downstream of the T-cell receptor (TCR) signal during T-cell development. The TCR signal is known to elicit different cellular responses at different stages of T-cell development. Whether E2A is still required for normal TCR signalling in mature T cells is unknown. Here we examined T-cell function after disruption of the E2A gene exclusively in the T-cell lineage. The conditional E2A-deficient mice show enhanced humoral immunity to a T-dependent antigen. We further show that E2A is involved in regulating TCR-induced T-cell proliferation events. However, E2A seems to play opposite roles in naïve and effector T cells. In the absence of E2A, TCR-induced proliferation is increased in naïve T cells and decreased in effector T cells. At older ages, these mice frequently develop antinuclear antibodies and proteinuria. Our studies suggest that E2A regulates T-cell function and the loss of E2A may promote age-dependent autoimmune diseases. PMID:15027899

Pan, Lihua; Bradney, Curtis; Zheng, Biao; Zhuang, Yuan

2004-01-01