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1

Removal of 17beta-estradiol (E2) and its chlorination by-products from water and wastewater using non-imprinted polymer (NIP) particles.  

PubMed

Endocrine disrupting compounds and their chlorination by-products are two classes of emerging contaminants. Surface water and wastewater treatment technologies have limitations in removing these contaminants. This study evaluated the ability of non-imprinted polymer particles (NIP) to remove the endocrine disruptor 17beta-estradiol (E2) and its chlorination by-products from water and wastewater. NIP effectively removed 98% of 10 mg/L E2 from wastewater. NIP were also effective in removing chlorination by-products of E2 by 84.9% after 10 mg/L E2 in water was chlorinated at 5 mg/L. In the presence of 5 mg/L humic acid, NIP were able to achieve removal of 10 mg/L E2 by greater than 99.9%. Furthermore, after chlorination of 10 mg/L E2 and 5 mg/L humic acid at 10 mg/L chlorine, NIP were also able to remove the chlorination by-products formed as well as the remaining E2 by greater than 99.9%. The presence of 5 mg/L humic acid did not adversely affect the adsorption efficiency. The results of this research indicate that NIPs have good potential as a final treatment step for surface water and wastewater treatment. PMID:22214083

Murray, Audrey; Ormeci, Banu; Lai, E P C

2011-01-01

2

One-generation reproductive toxicity study of dietary 17beta-estradiol (E2; CAS No. 50-28-2) in CD-1 (Swiss) mice.  

PubMed

There is no information on reproductive/developmental effects in mice from dietary estrogen. Therefore, 10 adult CD-1 mice/sex/group were administered dietary 17beta-estradiol (E2) at 0, 0.005, 0.05, 0.5, 2.5, 5, 10, and 50 ppm for 2-week prebreed, mating, gestation, lactation. F1 weanlings (3/sex/litter) were necropsied and 2/sex/litter were retained, with exposure, until vaginal patency (VP) or preputial separation (PPS) and then necropsied. Results included complete infertility at 2.5-50 ppm with normal mating indices. At 0.5 ppm (and above), F0 adult female uterus plus cervix plus vagina weights (UCVW) were increased. At 0.5 ppm: prolonged gestational length; increased F1 stillbirth index; reduced live birth index and litter size; decreased testes and epididymides weights at weaning; unaffected AGD on pnd 0 and 21; delayed PPS; increased undescended testes; unaffected prostate weight; accelerated VP; enlarged vaginas; fluid-filled uteri. At 0.05 ppm: no F0 reproductive effects, increased F1 weanling UCVW; delayed PPS. The NOEL was 0.005 ppm ( approximately 1 microg/kg/day). PMID:18242050

Tyl, Rochelle W; Myers, Christina B; Marr, Melissa C; Castillo, Nora P; Veselica, M Michael; Joiner, Ronald L; Dimond, Stephen S; Van Miller, John P; Stropp, Gisela D; Waechter, John M; Hentges, Steven G

2008-02-01

3

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

4

Adsorption, desorption, and steady-state removal of estrogenic hormone 17beta-estradiol by nanofiltration and ultrafiltration membranes.  

E-print Network

??Nanofiltration (NF) and ultrafiltration (UF) membranes were tested in cross-flow configuration for removal of the natural estrogenic hormone 17Beta-estradiol (E2). The NF membranes, FilmTec NF270… (more)

McCallum, Edward A.

2005-01-01

5

17beta-estradiol affects GABAergic transmission in developing hippocampus.  

PubMed

Estrogens are potent modulators of the nervous system. In particular, 17beta-estradiol was shown to affect GABAergic synaptic transmission in hippocampus of adult animals in vivo but much less is known on the impact of this hormone on the GABAergic system in the developing brains. We have recently shown that phasic and tonic GABAergic transmissions are strongly modulated upon long-term treatment with exogenous 17beta-estradiol in hippocampal neurons developing in vitro. To check for the long-term estrogen effect in a more physiological developmental model, we have investigated the GABAergic transmission in developing brains of P7-P40 animals, injected daily with 17beta-estradiol. We have found that such a treatment clearly increased GABAergic mIPSC frequency and amplitude while the onset and decay of mIPSCs were shortened. These effects were statistically significant in the youngest considered age group (P7-P13) with a tendency to disappear in older animals. Long-term treatment with estradiol did not change the susceptibility of mIPSC amplitude to upregulation by flurazepam while mIPSC decay was prolonged by this drug to a larger extent in 17beta-estradiol-treated animals. 17beta-estradiol strongly upregulated GABAergic tonic current but again this effect was restricted to the youngest group of animals. We conclude that 17beta-estradiol strongly modulates the GABAergic synaptic transmission but this effect critically depends on the animal age being the most prominent in youngest animals. PMID:18822277

Wójtowicz, Tomasz; Lebida, Katarzyna; Mozrzymas, Jerzy W

2008-11-19

6

Fully automated liquid chromatography-mass spectrometry determination of 17beta-estradiol in river water.  

PubMed

Surface modified molecularly imprinted polymers (SM-MIPs) for 17beta-estradiol (E2), utilizing 6-ketoecradiol as a pseudo template were prepared. MIPs for E2 were synthesized using 4-vinyl pyridine and ethylene dimethacrylate as a functional monomer and cross-linking agent, respectively. MIPs selectively retained E2 and provided excellent chromatographic resolution from interfering compounds inherent in river water sample matrices. Therefore, freshly prepared MIPs were applied to quantitative mass spectrometric (negative electrospray ionization mode) detection of low levels of E2 in river water sample. In order to pre-concentrate the target compound for HPLC analysis, column switching was coupled with a pretreatment column packed with the MIPs. The repeatability of actual determinations of river water sample, in which background E2 was not detected, spiked with 50 ng/L of E2 was 2.2% RSD with a detection limit and qualification limit of 1.8 and 5.4 ng/L, respectively. Surface modification of MIP particlefs packed in the pretreatment column provided selective affinity and on-line concentration of low levels of E2 while simultaneously eliminating sample matrix interference, resulting in a significant increase in sensitivity and reproducibility for liquid chromatography-mass spectrometry analysis of E2 in river water sample. PMID:16460748

Watabe, Yoshiyuki; Kubo, Takuya; Nishikawa, Teppei; Fujita, Tomio; Kaya, Kunimitsu; Hosoya, Ken

2006-07-01

7

Effects of 17beta-estradiol on chemically induced long-term depression.  

PubMed

In this study, we have investigated the effects of 17beta-estradiol (E2) on chemically induced long-term depression (LTD). LTD was induced by a brief application of N-methyl-D-aspartate (NMDA) or (R,S)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor agonist. Bath application of E2 alone potentiated population excitatory postsynaptic potentials. This potentiation was readily reversed by washing with control saline. The effect of E2 on NMDA-induced LTD was a conversion of LTD to long-term potentiation (LTP). An application of NMDA in the presence of E2 induced LTP. The induction of LTP was inhibited by an inhibitor of calcium/calmodulin dependent protein kinase (CaMKII). The results suggest that E2 potentiates NMDA receptor function and induces an increase in postsynaptic Ca2+ concentration. An increase in postsynaptic Ca2+ concentration activates CaMKII, leading to LTP. In contrast to NMDA-induced LTD, an application of DHPG in the presence of E2 induced significantly larger LTD. The results suggest that E2 potentiates an as yet unidentified process(es) in inducing LTD by an application of DHPG. The effects of E2 both on NMDA-induced and DHPG-induced LTD were suppressed by an estrogen receptor antagonist. PMID:15992584

Shiroma, Shinsaku; Yamaguchi, Tsutomu; Kometani, Kaoru

2005-07-01

8

Comparison of three enzyme immunoassays for measuring 17beta-estradiol in flushed dairy manure wastewater.  

PubMed

Natural steroidal estrogens are an environmental concern because low nanogram per liter concentrations in water can adversely affect aquatic vertebrate species by disrupting the normal function of their endocrine systems. There is a critical need to accurately measure estrogens in dairy wastes, a potential source of estrogens such as 17beta-estradiol, to assess the risk of estrogen contamination of agricultural drainage waters resulting from land application. Commercially available enzyme immunoassay (EIA) kits have been used for measuring 17beta-estradiol in livestock manure, but it is not known if different EIAs provide similar results. We compared three EIAs by measuring 17beta-estradiol in two samples of flushed dairy manure wastewater (FDMW). The measured concentrations of 17beta-estradiol in FDMW differed according to the immunoassay used. The differences were attributed to a matrix interference associated with coextracted humic substances. Future research should develop methods that enable routine measurement of 17beta-estradiol in livestock wastes by more conclusive analytical techniques such as gas chromatography-mass spectrometry. PMID:15356254

Hanselman, Travis A; Graetz, Donald A; Wilkie, Ann C

2004-01-01

9

Permeation of 17beta-estradiol through human vaginal and buccal mucosa.  

PubMed

Because of the relative scarcity of fresh human oral mucosa specimens for permeability studies, we investigated the use of human vaginal mucosa as a model of the former. In a previous study we demonstrated the comparable diffusion rate of water across human vaginal and buccal mucosa and proposed the use of the former as a suitable model of the latter for in vitro drug permeability studies. To further evaluate the human vaginal/buccal mucosa model, we decided to compare these two tissues with respect to their permeability to 17beta-estradiol. Clinically healthy human vaginal and buccal mucosa specimens were obtained during vaginal hysterectomies and different oral surgical procedures. The permeability of each tissue specimen to 17beta-estradiol was determined through the use of a continuous flow-through diffusion system. Specimens were examined histologically before and after experiments. Mean flux values for 17beta-estradiol across human buccal mucosa tended to be slightly higher than those observed for vaginal tissue, but no statistically significant differences could be demonstrated. The results from this study further support our hypothesis that human vaginal mucosa may be a suitable model of human buccal mucosa for in vitro drug permeability studies. PMID:9574947

van der Bijl, P; van Eyk, A D; Thompson, I O

1998-04-01

10

Sex hormone concentrations and gonad histology in brown trout (Salmo trutta) exposed to 17beta-estradiol and bisphenol A.  

PubMed

The impact of 17beta-estradiol (E2) and bisphenol A (BPA) on steroid hormone levels and gonad development in brown trout (Salmo trutta) was determined. Exposure took place from 0 to 63 days post-fertilisation (dpf) and gonad development was followed till 400 dpf. The onset of xenoestrogen metabolism was examined by measurements of whole body concentrations of bisphenol A (BPA) and its conjugation product bisphenol A glucuronic acid (BPAGA). Exposure to 500 ng E2/l led to an increase in E2 levels in the embryos and fry while 10 ng E2/l did not. Metabolic conversion of BPA to BPAGA began during the first weeks of embryonic development. Few consistent effects were found on the sex differentiation of the brown trout. Only one intersex fish (4.5%) was found among male fish at 400 dpf exposed to 500 ng E2/l. Females with male germ cells among the normally developing oocytes were observed in all groups (in up to 50% of the female fish, independently of exposure regime). The fact that exposure to 500 ng E2/l only caused subtle effects in a small number of individuals indicates that exposure during early life stages results in little to no induction of endocrine disruption in brown trout. PMID:18320304

Bjerregaard, Lisette Bachmann; Lindholst, Christian; Korsgaard, Bodil; Bjerregaard, Poul

2008-05-01

11

Differential expression of CYP102 in Bacillus megaterium by 17-beta-estradiol and 4-sec-butylphenol.  

PubMed

Previously we have reported the induction of CYP102 in Bacillus megaterium by 17beta-estradiol (E2) and 4-sec-butylphenol (4-sBP). Electrophoretic mobility shift assay analyses demonstrated that E2 and 4-sBP both cause a dose-dependent disassociation of the Bm3R1 repressor protein from its binding site on the operator sequence of the CYP102 gene. Equimolar combinations of E2 and 4-sBP demonstrated additive induction of CYP102 compared to equivalent samples of E2 and 4-sBP added alone. Two gene constructs were used in this investigation. One construct designated BMC143 contained the entire regulatory region of CYP102. The other gene construct, designated BMA45, had the "Barbie box" sequence deleted. While the induction of CYP102 by 4-sBP was much higher in the BMC 143 construct, E2 induced CYP102 in both constructs to the same extent. This difference in induction of CYP102 by these two inducers indicates that they act at different sites, either on the Bm3R1 repressor protein or on positive regulatory sites, or that they act, in part, through different mechanisms. PMID:12480527

Rowley, Christopher W; Rajnarayanan, Rajendram V; Hopkins, Nancy E; Alworth, William L

2003-01-01

12

The effects of 17beta-estradiol on various reproductive parameters in the hermaphrodite fish Kryptolebias marmoratus.  

PubMed

The effect of a single injection of 17beta-estradiol (E2) was evaluated in the hermaphrodite fish Kryptolebias marmoratus. The fish [average body weight (BW), 0.15+/-0.01 g] were injected with either two concentrations of E2 (1 and 100 microg/g BW) once intraperitoneally. They were sampled at intervals of 7, 15, and 30 days after a single E2 injection. Gonadosomatic index (GSI), hepatosomatic index (HSI), the frequency of gonadal development, number of ovulated eggs, and plasma steroids levels were measured. The transcript abundances of vitellogenin (VTG) and estrogen receptors (ERalpha and beta) mRNA in the liver were also analyzed using quantitative real time polymerase chain reaction (real time PCR). GSI and the frequency of mature oocytes in the 100-microg E2-exposed group decreased compared to that of the control group during the experiment, and the number of ovulated eggs in the 100-microg E2-exposed group was lower when compared to the other groups. However, plasma E2 and 11-ketotestosterone (11-KT) levels were not significantly different between the experimental groups. On the other hand, plasma testosterone level and VTG mRNA abundance in the 100-microg E2-exposed group were significantly lower than the control group after 30 days. These results indicate that E2 stimulation at high concentration interferes with reproductive phenomena through delayed response. In addition, HSI in the 100-microg E2-exposed group and ERalpha mRNA abundance in the 1-microg E2-exposed group were significantly higher than the control group at 7 days after E2 injection, although there was no significant difference in HSI and ERalpha mRNA between all groups at 30 days. These results indicate temporal responses in reproductive parameters following high-dose E2 exposure in the hermaphrodite fish K. marmoratus. PMID:20006390

Park, Chang-Beom; Aoki, Jun-Ya; Lee, Jae-Seong; Nagae, Masaki; Lee, Young-Don; Sakakura, Yoshitaka; Hagiwara, Atsushi; Soyano, Kiyoshi

2010-03-01

13

17-beta-estradiol increases mitogenic activity of medium from cultured preadipocytes of massively obese persons.  

PubMed Central

Having reported that omental preadipocytes from massively obese persons release into the culture medium proteins mitogenic for preadipocytes, this study aimed to determine whether estrogens contribute to the production of these factors. Sub-cultured omental preadipocytes from 13 massively obese women were grown in the presence or absence of 17-beta-estradiol, and during the last 24 h the conditioned medium was prepared in the absence of serum. Media from cells of 8 of 13 subjects contained significantly higher mitogenic activity when grown in the presence of 17-beta-estradiol. 17-Alpha-estradiol was not effective. The bioassay system involved rat perirenal preadipocytes, since these have been well characterized. Partial purification by gel filtration chromatography indicated that the estrogen-dependent factors had Mr greater than 250,000 and approximately 30,000. Thus, estrogens might contribute to the development of massive obesity in genetically susceptible subjects by promoting the production of paracrine/autocrine principles by adipose cells. PMID:2723065

Cooper, S C; Roncari, D A

1989-01-01

14

Effects of 17beta-estradiol and 4-nonylphenol on osmoregulation and hepatic enzymes in gilthead sea bream (Sparus auratus).  

PubMed

Sexually immature Sparus auratus were injected intraperitoneally with coconut oil either alone (control) or containing 17beta-estradiol (E2, 10 microg/g body mass) or 4-nonyphenol (4-NP, 100 and 200 microg/g body mass) and sampled 10 days later. Gill and kidney Na(+),K(+)-ATPase activities, plasma levels of E2 and cortisol, plasma osmolites (osmolality, sodium and chloride) and metabolites (glucose, lactate, proteins and triglycerides) were examined. Livers were used for measuring hepatosomatic index (HSI) and determinations of the activities of antioxidant defences catalase (CAT) and total glutatione peroxidase (t-GPX), the CYP1A-dependent, 7-ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST). HSI and plasma levels of E2 were significantly increased in E2 -treated fish. E2 treatment enhanced plasma osmolality, glucose, triglycerides and proteins, but had no effect on plasma cortisol, and gill and kidney Na(+),K(+)-ATPase activities. Hepatic activities of EROD, GST and CAT were significantly decreased after E2 administration, whereas t-GPX remained unaffected. Treatment with 200 microg/g 4-NP caused a slight increase in plasma E2 relative to the control group. Plasma glucose and protein levels were not affected by 4-NP, while triglycerides were increased. Fish treated with the higher dose of 4-NP displayed a clear reduction in kidney Na(+),K(+)-ATPase activity, together with increases in plasma osmolality, relative to the control group. High 4-NP also caused a significant decrease in EROD and an increase in GST activity. Our results confirm the regulation of the natural estrogen E2 and the weak xenoestrogen 4-NP on osmoregulation and biotransformation enzymes in a partially similar manner. The actions of xenoestrogens on critical physiological processes may have an ecological significance as it can reduce adaptability and capacity to metabolise xenobiotics under stressful conditions. PMID:17251064

Carrera, Erkuden Pérez; García-López, Angel; Martín del Río, María del Pilar; Martínez-Rodríguez, Gonzalo; Solé, Montserrat; Mancera, Juan Miguel

2007-03-01

15

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

16

Progesterone, but not 17beta-estradiol, increases TNF-alpha secretion in U937 monocytes.  

PubMed

The Women Health Initiative Clinical trial results suggest that post-menopausal women receiving estrogen + progesterone are at risk for heart disease compared with estrogen alone supplemented women. We examined the hypothesis that progesterone but not 17beta-estradiol (E) increases the secretion of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha. U937 human monocytes were cultured with normal or high glucose in the presence and absence of estrogen or progesterone at 37 degrees C for 24 h. Results show that estrogen inhibits IL-6 but not TNF-alpha secretion (p < 0.05) in monocytes activated by lipopolysaccharide (LPS) or high glucose. In addition, progesterone increased the TNF-alpha secretion in activated monocytes. Thus, progesterone supplementation along with estrogen may increase blood levels of pro-inflammatory cytokine TNF-alpha and thus risk of heart disease in post-menopausal women. PMID:15135803

Jain, Sumati K; Kannan, Krishnaswamy; Prouty, Leonard; Jain, Sushil K

2004-05-01

17

Fate of sulfamethoxazole, 4-nonylphenol, and 17beta-estradiol in groundwater contaminated by wastewater treatment plant effluent.  

PubMed

Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant degradation product 4-nonylphenol (NP), the solvent tetrachloroethene (PCE), and the disinfectant 1,4-dichlorobenzene (DCB). Comparison of the 2005 sampling results to data collected from the same wells in 1985 indicates that PCE and DCB are transported more rapidly in the aquiferthan NP, consistent with predictions based on compound hydrophobicity. Natural gradient in situ tracer experiments were conducted to evaluate the subsurface behavior of SX, NP, and the female sex hormone 17beta-estradiol (E2) in two oxic zones in the aquifer: (1) a downgradient transition zone at the interface between the contamination plume and the overlying uncontaminated groundwater and (2) a contaminated zone located beneath the infiltration beds, which have not been loaded for 10 years. In both zones, breakthrough curves for the conservative tracer bromide (Br-) and SX were nearly coincident, whereas NP and E2 were retarded relative to Br- and showed mass loss. Retardation was greater in the contaminated zone than in the transition zone. Attenuation of NP and E2 in the aquifer was attributed to biotransformation, and oxic laboratory microcosm experiments using sediments from the transition and contaminated zones show that uniform-ring-labeled 14C 4-normal-NP was biodegraded more rapidly 130-60% recovered as 14CO2 in 13 days) than 4-14C E2 (20-90% recovered as 14CO2 in 54 days). There was little difference in mineralization potential between sites. PMID:19673274

Barber, Larry B; Keefe, Steffanie H; Leblanc, Denis R; Bradley, Paul M; Chapelle, Francis H; Meyer, Michael T; Loftin, Keith A; Kolpin, Dana W; Rubio, Fernando

2009-07-01

18

Protective effects of 17beta-estradiol and trivalent chromium on interleukin-6 secretion, oxidative stress, and adhesion of monocytes: relevance to heart disease in postmenopausal women.  

PubMed

Postmenopausal diabetic women are at greater risk for heart disease compared with men of similar age and with other risk factors. We examined the hypothesis that 17beta-estradiol and trivalent chromium inhibit secretion of the pro-inflammatory cytokine interleukin (IL)-6 and oxidative stress in monocytes exposed to high glucose (HG). U937 human monocytes were cultured with HG (30 mM) with and without 17beta-estradiol (0-1000 nM) and chromium chloride (Cr(3+), 0-10 muM) at 37 degrees C for 24 h. Results show that 17beta-estradiol inhibits IL-6 and adhesion to endothelial cells (p <. 05) by HG-treated monocytes. Treatment with 17beta-estradiol+Cr(3+) required a significantly lower dose of estradiol-17beta compared with 17beta-estradiol alone for IL-6 inhibition. 17beta-Estradiol+Cr(3+) also inhibited lipid peroxidation and the adhesivity to human endothelial cells in HG-treated monocytes. Thus, 17beta-estradiol+Cr(3+) inhibits oxidative stress, IL-6 secretion, and monocytic adhesion to endothelial cells, risk factors in the development of heart disease. The female body requires E but studies on some patients indicate side effects with increased amounts of 17beta-estradiol-supplementation. The potential benefit of a lower estrogen dose in combination with chromium is novel and needs to be explored in postmenopausal diabetic women. PMID:15528032

Jain, Sumati K; Rogier, Kimberly; Prouty, Leonard; Jain, Sushil K

2004-12-01

19

17Beta-estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats.  

PubMed

We recently identified a myelinated vagal afferent subpopulation (Ah type) far more prevalent in female than male rats and showed that this difference extends to functionally specific visceral sensory afferents, baroreceptors of the aortic arch. Excitability of myelinated Ah-type afferents is markedly reduced after ovariectomy (OVX). Here we tested the hypothesis that 17beta-estradiol can selectively restore excitability of these sex-specific vagal afferents. Acutely isolated vagal afferent neurons (VGN) from intact and OVX adult female rats were used with patch-clamp technique and current-clamp protocols to assess the effect of acute application of 17beta-estradiol on neuronal excitability. At over physiologically relevant 17beta-estradiol concentrations for rat (1-10 nM) excitability of myelinated Ah-type vagal afferents is restored to discharge frequencies comparable to those in intact females, albeit with some interesting differences related to burst and sustained patterns of neuronal discharge. Restoration of excitability occurs within 3 min of hormone application and is stereo specific, because 1,000 nM 17alpha-estradiol fails to alter excitability. Furthermore, activation of G protein-coupled estrogen receptor GPR30 with highly selective agonist G-1 similarly restores excitability of Ah-type afferents. The effectiveness of 17beta-estradiol and G-1 is completely eliminated by application of high-affinity estrogen receptor ligand ICI-182,780. 17beta-Estradiol conjugated with BSA is approximately 70% as effective as 17beta-estradiol alone in restoring Ah-type VGN excitability. These data support our conclusions that the cellular mechanisms leading to rapid restoration of neuronal excitability of myelinated Ah-type VGN after OVX occur, at least in part, via membrane-bound estrogen receptors. We contend that recovery of high-frequency discharge at physiologically relevant 17beta-estradiol concentrations implies that this unique subtype of low-threshold myelinated vagal afferent may account for some of the sex-related differences in visceral organ system function. Sex differences in cardiovascular and gastrointestinal function and the potential role of GPR30 in modulation of sex-specific myelinated Ah-type vagal afferents are discussed. PMID:19570896

Qiao, Guo-Fen; Li, Bai-Yan; Lu, Yan-Jie; Fu, Yi-Li; Schild, John H

2009-09-01

20

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

21

Sex differences in exercise metabolism and the role of 17-beta estradiol.  

PubMed

Women oxidize more lipid and less carbohydrate and protein compared with men during endurance exercise. The increase in fat oxidation is associated with higher intramyocellular lipid content and use as well as greater adipocyte lipolysis. Glucose rates of appearance and disappearance are lower for women than for men, with no change in basal muscle glycogen, and some evidence for muscle glycogen sparing during endurance exercise. Women oxidize less protein compared with men and show lower leucine oxidation during exercise. The consistent and robust finding of higher mRNA abundance for most components of fat-oxidation pathways in women compared with men is directionally consistent with the substrate-oxidation data. A lack of directional consistency between mRNA species involved in carbohydrate and protein metabolism and the known sex differences during exercise implies that fat oxidation is regulated and that carbohydrate and protein oxidation follow by metabolic demand. Administration of 17-beta-estradiol to men recapitulates most of the described sex differences in metabolism and mRNA content. The greater fat oxidation for women during submaximal endurance exercise compared with men seems to occur partly through a sex hormone-mediated enhancement of lipid-oxidation pathways. PMID:18317381

Tarnopolsky, Mark A

2008-04-01

22

Primary induction of vitellogenin mRNA in the rooster by 17beta-estradiol.  

PubMed

We have studied the kinetics of vitellogenin mRNA accumulation in rooster liver after a primary injection of 17beta-estradiol. The levels of vitellogenin mRNA have been determined both by hybridization of total cellular RNA to vitellogenin cDNA and by translation of vitellogenin mRNA in a wheat germ cell-free system. The results obtained by both methods of analysis are in good agreement and indicate that vitellogenin mRNA is present in the liver of normal roosters at a level of 0-5 molecules per liver cell and increases in amount during the 3 days following injection of estrogen, reaching a level of almost 6000 molecules per cell at the peak of the response. The level of vitellogenin mRNA declined exponentially during the next 14 days with a half-life of 29 hr, reaching a level of less than 10 molecules per cell at 17 days after injection of the hormone. The levels of vitellogenin mRNA after stimulation with estrogen have been correlated with the in vivo rate of synthesis of the vitellogenin polypeptide. The results indicate that the rate of vitellogenin synthesis is closely correlated with the level of vitellogenin mRNA. On the basis of these findings, we conclude that vitellogenin mRNA does not exist in the liver in an untranslated form after withdrawal from estrogen. PMID:273910

Burns, A T; Deeley, R G; Gordon, J I; Udell, D S; Mullinix, K P; Goldberger, R F

1978-04-01

23

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

24

Serum concentrations of 17beta-estradiol in ovariectomized rats during two times six weeks crossover treatment by daily injections in comparison with slow-release pellets.  

PubMed

Estrogens exert widespread biological functions that reach far beyond their well-known role in reproduction. Exogenous administration of 17beta-estradiol to ovariectomized experimental animals is of the utmost importance in elucidating its mechanisms of action. In the present study, we compared two different modes of exogenous administration of 17beta-estradiol to ovariectomized rats in relation to the serum 17beta-estradiol concentrations over prolonged periods of time. 17beta-estradiol was administered either by slow-release pellets (Innovative Research of America, Sarasota, Fl. 34236, USA, 90-day release, NHH-115, 1.5 mg) or by daily subcutaneous injections of 15 microg 17beta-estradiol dissolved in sesame oil. After 6 weeks, the mode of administration of estradiol was changed to the opposite method and continued for a further 6 weeks. Blood samples for measurement of serum 17beta-estradiol were taken every second week. After 2 weeks, the serum concentrations of 17beta-estradiol in group A initially receiving the pellets were 73 % higher (p<0.001) compared to those of group B receiving daily injections. The difference was even more prominent, 580 % (p<0.001), after 4 weeks. Steady state was reached at week 6 in group A, but already by week 4 in group B. Once steady state was reached, the concentrations were the same in both groups for the remainder of the experiment (12 weeks in total). Our study indicates that steady-state concentrations of 17beta-estradiol occur 5-6 weeks later than the 48 h the manufacturer of the slow-release pellets claims. PMID:16319044

Theodorsson, A; Hilke, S; Rugarn, O; Linghammar, D; Theodorsson, E

2005-01-01

25

Oxidation products of stigmasterol interfere with the action of the female sex hormone 17beta-estradiol in cultured human breast and endometrium cell lines.  

PubMed

Phytosterols are constituents of plant membranes and are thus contained in low concentrations in vegetable products as well as at high concentrations in functional food designed to reduce serum cholesterol levels. Similar to ChOL, phytosterols are oxidized chemically in food and by biotransformation in vivo. Although oxyphytosterols have been detected in the serum of healthy human subjects, little is known of their biological activity. Therefore, the estrogenic and antiestrogenic activities of a mixture of six oxidation products of stigmasterol (oxy-StOL) were determined at the following endpoints: (i) the affinity to isolated human estrogen receptors (ER), (ii) the basal and 17beta-estradiol (E2)-induced expression of the alkaline phosphatase (AlP) in human endometrial adenocarcinoma (Ishikawa) cells, and (iii) the basal and E2-induced proliferation of human breast adenocarcinoma (MCF-7) cells. Oxy-StOL was able to replace E2 from human ERalpha and ERbeta and induced a weak estrogenic response in MCF-7 cells. Moreover, the E2-induced activity of the AlP in Ishikawa cells as well as the E2-induced proliferation of MCF-7 cells were decreased at noncytotoxic concentrations (up to 10 microM), indicating that at least one component of oxy-StOL represents an estrogen-active compound which might interfere with endogenous estrogens. PMID:17579897

Newill, Heike; Loske, Renate; Wagner, Jörg; Johannes, Christian; Lorenz, Reinhard L; Lehmann, Leane

2007-07-01

26

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

27

Organochlorine compounds in liver and concentrations of vitellogenin and 17beta-estradiol in plasma of sea bass fed with a commercial or with a natural diet.  

PubMed

Results from previous experiments directed to determine the effect of different nutritional factors or the effect of xenobiotics on hormonal control of reproduction, lead to the hypothesis that hormonal perturbations repeatedly observed in sea bass (Dicentrarchus labrax) broodstock feeding commercial diets could have been caused by the presence of aryl hydrocarbon receptor (AhR) ligands, such as dioxins, furans and polychlorinated biphenyls (PCBs) in the diet. To evaluate this hypothesis, dioxins and related compounds were analysed in liver of female sea bass fed with a commercial or with a natural diet consisting of trash fish (bogue, Boops boops), and concentrations of vitellogenin (VTG) and 17beta-estradiol (E2) were determined in plasma obtained previously in monthly samplings of these animals. As observed in other experiments, females fed with a commercial diet exhibited lower VTG and higher E2 plasma levels than females fed with the natural diet. In liver, sea bass fed with the commercial diet exhibited a profile clearly dominated by high-chlorinated dioxins while in fish fed with the natural diet this profile was dominated by low chlorinated furans. However, typical AhR ligands, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin showed no differences between groups or, as is the case of planar PCBs, showed higher concentrations in the liver of fish fed with the natural diet. These results do not permit to explain the observed hormonal alterations by a possible antiestrogenic effect caused by dioxins and related compounds. PMID:16213605

Navas, J M; Merino, R; Jiménez, B; Rivera, J; Abad, E; Zanuy, S; Carrillo, M

2005-11-30

28

Variation among rainbow trout (Oncorhynchus mykiss) estrogen receptor isoform 3' untranslated regions and the effect of 17beta-estradiol on mRNA stability in hepatocyte culture.  

PubMed

Adenine and uridine (AU)-rich elements in the 3' untranslated region (3'UTR) have been implicated in the 17beta-estradiol (E2) stabilization of vertebrate estrogen receptor (ER) mRNAs. To date, fishes have the most complex arrangement of nuclear ERs with up to two isoforms of each of the two genes in some species (i.e., four different ERs). The objective of this study was to analyze the sequence variation of 3'UTRs among the four ER isoforms in the rainbow trout and determine to what degree it is responsible for the estrogen-induced increase of ER mRNAs in the liver of this fish. This was done by comparing the 3'UTR DNA sequence length and composition, and by measuring expression of ER isoform 3'UTR luciferase reporter constructs in primary cultures of trout hepatocytes treated with E2. There were large differences both in overall length and in sequence composition among the four ER isoform 3'UTRs. The ERalpha1 sequence was the longest and the only one of the four that contained multiple copies of the canonical AU-rich elements (AUUUA) as well as the stability sequence (GCUGAU). E2 treatment significantly increased the luciferase activity in cells transiently transfected with the ERalpha1 reporter construct, relative to cells transfected with reporter vectors containing the other three ER isoform 3'UTRs or the parental vector control. These results support the hypothesis that the E2-induced increase in hepatic ERalpha1 mRNA in rainbow trout is due in part to sequence variability among ER isoform 3'UTRs. We conclude that posttranscriptional stabilization of ER mRNA by E2 appears to be conserved among vertebrates. PMID:20438355

Boyce-Derricott, Josh; Nagler, James J; Cloud, Joseph G

2010-05-01

29

DNA demethylation by 5-aza-2-deoxycytidine treatment abrogates 17 beta-estradiol-induced cell growth and restores expression of DNA repair genes in human breast cancer cells.  

PubMed

Prolonged exposure to elevated levels of estrogen is a risk factor for breast cancer. Though increased cell growth and loss of DNA repair capacity is one of the proposed mechanisms for estrogen-induced cancers, the mechanism through which estrogen induces cell growth and decreases DNA repair capacity is not clear. DNA hypermethylation is known to inactivate DNA repair genes and apoptotic response in cancer cells. Therefore, the objective of this study was to determine the role of DNA hypermethylation in estrogen-induced cell growth and regulation of DNA repair genes expression in breast cancer cells. To achieve this objective, the estrogen-responsive MCF-7 cells either pretreated with 5-aza-2-deoxycytidine (5-aza-dC) or untreated (as control) were exposed to 17 beta-estradiol (E2), and its effect on cell growth and expression of DNA repair genes were measured. The result revealed that 5-aza-dC abrogates the E2-induced growth in MCF-7 cells. An increased expression of OGG1, MSH4, and MLH1 by 5-aza-dC treatment alone, suggest the DNA hypermethylation as a potential cause for decreased expression of these genes in MCF-7 cells. The decreased expression of ERCC1, XPC, OGG1, and MLH1 by E2 alone and its restoration by co-treatment with 5-aza-dC further suggest that E2 reduces the expression of these DNA repair genes potentially through promoter hypermethylation. Reactivation of mismatch repair (MMR) gene MLH1 and abrogation of E2-induced cell growth by 5-aza-dC treatment suggest that estrogen causes increased growth in breast cancer cells potentially through the inhibition of MMR-mediated apoptotic response. In summary, this study suggests that estrogen increases cell growth and decreases the DNA repair capacity in breast cancer cells, at least in part, through epigenetic mechanism. PMID:22082530

Singh, Kamaleshwar P; Treas, Justin; Tyagi, Tulika; Gao, Weimin

2012-03-01

30

The ontogeny of nuclear estrogen receptor isoform expression and the effect of 17beta-estradiol in embryonic rainbow trout (Oncorhynchus mykiss).  

PubMed

Ligand bound nuclear estrogen receptor (ER) acts as a transcription factor regulating the expression of estrogen dependent genes. There are four nuclear ER isoforms in rainbow trout (Oncorhynchus mykiss). The objective of this study was to measure whole body mRNA levels of the two ERalpha isoforms (alpha1/alpha2) and the two ERbeta isoforms (beta1/beta2) in male and female embryos from 50 to 600 degree-days (DD; days post-fertilizationxwater temperature) and in embryos exposed to vehicle or 17beta-estradiol (E2) for 2h at 230, 240 and 250 DD. All four isoforms were detected at every time point in both sexes. Sexual dimorphism was rarely observed; at 50 DD the level of ERalpha2 mRNA was significantly greater in males than in females and at 100 DD the level of ERbeta1 mRNA was significantly greater in females than in males (p<0.05). Expression profiles of the two ERalpha isoforms were slightly different from one another, whereas the ERbeta isoforms exhibited similar expression patterns. The effect of E2 was not different between male and female embryos. The level of ERalpha1 mRNA increased significantly at 240 DD; a similar but not statistically significant trend was observed at 230 and 250 DD. Despite the critical role of estrogen during sex differentiation in rainbow trout, the receptivity to this hormone as measured by the response in mRNA levels of ER appears to be largely the same between males and females and ERalpha1 is the only E2 responsive isoform. PMID:19818378

Boyce-Derricott, Josh; Nagler, James J; Cloud, J G

2010-02-01

31

17 beta-Estradiol regulates prolactin secretion but not cell proliferation of GH3B6 cells in chemically defined medium.  

PubMed

The effects of 17 beta-estradiol on proliferation and prolactin secretion by a clonal rat pituitary cell, GH3B6, have been investigated in a chemically defined medium (Ham's F12, transferrin, insulin and parathyroid hormone). Under these conditions, 17 beta-estradiol alone (5 X 10(-14)-5 X 10(-9) M) was not a mitogen for GH3B6 cells as shown by cell counts and DNA measurements. However, it slowed down the drop in prolactin production induced by culture in this chemically defined medium. After 3 and 7 days it stimulated PRL production up to 5 times in a dose-dependent manner. This secretory response was abolished by tamoxifen, and not mimicked by progesterone, testosterone or dexamethasone. The thyroliberin-induced stimulation of prolactin production occurred more rapidly (24 h) than and was additive to the 17 beta-estradiol response, suggesting that these two factors act through independent mechanisms. PRL neosynthesis in culture was attested to by the incorporation of [35S]methionine (5 h) into immunoprecipitable prolactin. Neither 17 beta-estradiol nor thyroliberin increases specifically prolactin radioactivity, although they strongly decreased the specific activity of prolactin in both cells and medium. This suggests that they mostly acted by decreasing PRL turnover rate. PMID:3918892

de Carvalho-Brunet, N; Picart, R; Tixier-Vidal, A

1985-01-01

32

Regulated expression of matrix metalloproteinases, inflammatory mediators, and endometrial matrix remodeling by 17beta-estradiol in the immature rat uterus  

PubMed Central

Background Administration of a single physiological dose of 17beta-estradiol (E2:40 microg/kg) to the ovariectomized immature rat rapidly induces uterine growth and remodeling. The response is characterized by changes in endometrial stromal architecture during an inflammatory-like response that likely involves activated matrix-metalloproteinases (MMPs). While estrogen is known as an inducer of endometrial growth, its role in specific expression of MMP family members in vivo is poorly characterized. E2-induced changes in MMP-2, -3, -7, and -9 mRNA and protein expression were analyzed to survey regulation along an extended time course 0-72 hours post-treatment. Because E2 effects inflammatory-like changes that may alter MMP expression, we assessed changes in tissue levels of TNF-alpha and MCP-1, and we utilized dexamethasone (600 microg/kg) to better understand the role of inflammation on matrix remodeling. Methods Ovariectomized 21 day-old female Sprague-Dawley rats were administered E2 and uterine tissues were extracted and prepared for transmission electron microscopy (TEM), mRNA extraction and real-time RT-PCR, protein extraction and Western blot, or gelatin zymography. In inhibitor studies, pretreatment compounds were administered prior to E2 and tissues were harvested at 4 hours post-hormone challenge. Results Using a novel TEM method to quantitatively assess changes in stromal collagen density, we show that E2-induced matrix remodeling is rapid in onset (< 1 hour) and leads to a 70% reduction in collagen density by 4 hours. Matrix remodeling is MMP-dependent, as pretreatment with batimastat ablates the hormone effect. MMP-3, -7, and -9 and inflammatory markers (TNF-alpha and MCP-1) are transiently upregulated with peak expression at 4 hours post-E2 treatment. MMP-2 expression is increased by E2 but highest expression and activity occur later in the response (48 hours). Dexamethasone inhibits E2-modulated changes in collagen density and expression of MMPs although these effects are variable. Dexamethasone upregulates MMP-3 mRNA but not protein levels, inhibiting E2-induced upregulation of MMP-7, and -9, and MCP-1 mRNA and protein but not inhibiting the hormone-induced increase in TNF-alpha mRNA. Conclusion The data demonstrate that E2-regulated endometrial remodeling is rapid in onset (<1 hour) and peak expression of MMPs and inflammatory mediators correlates temporally with the period of lowest stromal collagen density during uterine tissue hypertrophy. PMID:19889233

Russo, Louise A; Peano, Bryan J; Trivedi, Shreya P; Cavalcanto, Todd D; Olenchock, Benjamin A; Caruso, Joseph A; Smolock, Amanda R; Vishnevsky, Oleg; Gardner, Russell M

2009-01-01

33

17beta-estradiol-mediated neuroprotection and ERK activation require a pertussis toxin-sensitive mechanism involving GRK2 and beta-arrestin-1.  

PubMed

17-beta-Estradiol (E2) is a steroid hormone involved in numerous bodily functions, including several brain functions. In particular, E2 is neuroprotective against excitotoxicity and other forms of brain injuries, a property that requires the extracellular signal-regulated kinase (ERK) pathway and possibly that of other signaling molecules. The mechanism and identity of the receptor(s) involved remain unclear, although it has been suggested that E2 receptor alpha (ERalpha) and G proteins are involved. We, therefore, investigated whether E2-mediated neuroprotection and ERK activation were linked to pertussis toxin (PTX)-sensitive G-protein-coupled effector systems. Biochemical and image analysis of organotypic hippocampal slices and cortical neuronal cultures showed that E2-mediated neuroprotection as well as E2-induced ERK activation were sensitive to PTX. The sensitivity to PTX suggested a possible role of G-protein- and beta-arrestin-mediated mechanisms. Western immunoblots from E2-treated cortical neuronal cultures revealed an increase in phosphorylation of both G-protein-coupled receptor-kinase 2 and beta-arrestin-1, a G-protein-coupled receptor adaptor protein. Transfection of neurons with beta-arrestin-1 small interfering RNA prevented E2-induced ERK activation. Coimmunoprecipitation experiments indicated that E2 increased the recruitment of beta-arrestin-1 and c-Src to ERalpha. These findings suggested that ERalpha is regulated by a mechanism associated with receptor desensitization and downregulation. In support of this idea, we found that E2 treatment of cortical synaptoneurosomes resulted in internalization of ERalpha, whereas treatment of cortical neurons with the ER agonists E-6-BSA-FITC [beta-estradiol-6-(O-carboxymethyl)oxime-bovine serum albumin conjugated with fluorescein isothiocyanate] and E-6-biotin [1,3,5(10)-estratrien-3,17beta-diol-6-one-6-carboxymethloxime-NH-propyl-biotin] resulted in agonist internalization. These results demonstrate that E2-mediated neuroprotection and ERK activation involve ERalpha activation of G-protein- and beta-arrestin-mediated mechanisms. PMID:19339617

Dominguez, Reymundo; Hu, Eric; Zhou, Miou; Baudry, Michel

2009-04-01

34

Effects of 17 beta-estradiol and methyl testosterone on the activity of the thyroid gland in rainbow trout, Salmo gairdneri Richardson.  

PubMed

Methyl testosterone (MT) and 17 beta-estradiol (E2), suspended either in sesame oil (and injected on alternate days) or in warm hydrogenated coconut oil (and injected once in the form of an "implant"), were administered intraperitoneally to nonvitellogenic rainbow trout (Salmo gairdneri Richardson). When given as sesame oil injections E2 significantly reduced plasma triiodo-L-thyronine (T3) levels and thyroid epithelial cell height (TEH), but had no apparent effect on plasma L-thyroxine (T4) levels. When given as a coconut oil "implant" E2 significantly reduced both plasma T3 and T4 levels. E2 also elevated the hepatosomatic index (HSI), plasma Ca2+, Mg2+, protein, triglyceride, and alkali-labile phosphoprotein (ALP) and hepatic lipid concentration, decreased hepatic glycogen levels, but was without effect on plasma Na+ and glucose levels. MT given via sesame oil injections significantly lowered plasma T3 levels, but was without effect on plasma T4 concentrations or TEH; the T3-lowering effect of MT was not evident when the steroid was given in the form of a coconut oil "implant." MT also effected a lowering of plasma Mg2+ and protein and hepatic lipid concentrations, but had no significant effect on HSI, plasma Na+, glucose triglyceride and ALP concentration, or hepatic glycogen levels. MT given as a series of injections lowered plasma Ca2+ levels, but was without effect when given as an "implant" and had no significant effect on plasma Ca2+. Intraperitoneal injections of ovine thyrotropin (TSH) (2 micrograms/g body wt) elicited an increase in both plasma T4 and T3 levels within 24 hr in E2-, MT-, and oil-injected groups. The TSH-stimulated increase in plasma T4 level was significantly less in the E2-treated fish compared with oil- or MT-treated groups. The TSH-stimulated increase in plasma T3 levels in both groups of steroid-treated fish was significantly less than that of the oil-injected controls. PMID:4076757

Leatherland, J F

1985-12-01

35

Human macrophage cholesterol efflux potential is enhanced by HDL-associated 17beta-estradiol fatty acyl esters.  

PubMed

High-density lipoprotein (HDL) and 17beta-estradiol independently provide protection against atherosclerosis. Estradiol fatty acyl esters incorporate into HDL and whether this association enhances the atheroprotective properties of HDL is unclear. The study objective was to clarify the role that HDL-associated estradiol fatty acyl esters play in mediating the initial steps of reverse cholesterol transport. Cholesterol efflux potential from cholesterol loaded macrophage cells to HDL-associated estradiol ester or between HDL from premenopausal women and age-matched males and the cellular receptors involved were examined. Human THP-1 macrophages, loaded with [(3)H]cholesterol oleate, acetylated low-density lipoprotein, were pretreated with or without SR-BI inhibitors or an estrogen receptor antagonist and incubated with either HDL-associated estradiol oleate, HDL lacking estradiol oleate, or isolated HDL from females and males, and cholesterol efflux was measured. Cellular internalization and hydrolysis of HDL-associated [(3)H]estradiol ester were determined. HDL-associated estradiol oleate and premenopausal female HDL demonstrated significantly higher cholesterol efflux capacity to media than male HDL. SR-BI and estrogen receptor inhibition significantly reduced this effect. Cells internalized and subsequently hydrolyzed HDL-associated [(3)H]estradiol ester to [(3)H]estradiol and again SR-BI inhibition reduced this internalization. These results demonstrate that HDL-mediated macrophage cholesterol efflux potential is enhanced by HDL-associated estradiol esters. PMID:19406243

Badeau, Robert M; Metso, Jari; Wähälä, Kristiina; Tikkanen, Matti J; Jauhiainen, Matti

2009-08-01

36

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

37

Contrasting effects of increased and decreased dopamine transmission on latent inhibition in ovariectomized rats and their modulation by 17beta-estradiol: an animal model of menopausal psychosis?  

PubMed

Women with schizophrenia have later onset and better response to antipsychotic drugs (APDs) than men during reproductive years, but the menopausal period is associated with increased symptom severity and reduced treatment response. Estrogen replacement therapy has been suggested as beneficial but clinical data are inconsistent. Latent inhibition (LI), the capacity to ignore irrelevant stimuli, is a measure of selective attention that is disrupted in acute schizophrenia patients and in rats and humans treated with the psychosis-inducing drug amphetamine and can be reversed by typical and atypical APDs. Here we used amphetamine (1 mg/kg)-induced disrupted LI in ovariectomized rats to model low levels of estrogen along with hyperfunction of the dopaminergic system that may be occurring in menopausal psychosis, and tested the efficacy of APDs and estrogen in reversing disrupted LI. 17beta-Estradiol (50, 150 microg/kg), clozapine (atypical APD; 5, 10 mg/kg), and haloperidol (typical APD; 0.1, 0.3 mg/kg) effectively reversed amphetamine-induced LI disruption in sham rats, but were much less effective in ovariectomized rats; 17beta-estradiol and clozapine were effective only at high doses (150 microg/kg and 10 mg/kg, respectively), whereas haloperidol failed at both doses. Haloperidol and clozapine regained efficacy if coadministered with 17beta-estradiol (50 microg/kg, an ineffective dose). Reduced sensitivity to dopamine (DA) blockade coupled with spared/potentiated sensitivity to DA stimulation after ovariectomy may provide a novel model recapitulating the combination of increased vulnerability to psychosis with reduced response to APD treatment in female patients during menopause. In addition, our data show that 17beta-estradiol exerts antipsychotic activity. PMID:20237462

Arad, Michal; Weiner, Ina

2010-06-01

38

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

PubMed

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

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

2008-08-01

39

17Beta-estradiol delivered by three different matrix patches 50 microg/day: a three way cross-over study in 21 postmenopausal women.  

PubMed

The aim of this study was to investigate the systemic bioavailability and plasma profiles of 17beta-estradiol (E2) after the application of three matrix patches for the transdermal delivery of E2: Menorest, Tradelia, and Estraderm MX claiming to deliver a dosage of 50 microg E2/day. All three patches were each worn randomly by 21 postmenopausal women volunteers over a 4-day period (i.e. 96 h). Each of the three treatment periods were separated by an at least 7 day wash out period according to a randomized, 3-way crossover design. Blood samples were taken from the antecubital vein before and 3, 6, 9, 12, 24, 28, 33, 48, 57, 72, 81, and 96 h after application. E2 plasma values were determined by a specific direct radioimmunoassay method. The following pharmacokinetic parameters were evaluated: AUC0-96h, Cmax, Tmax, Cmin, C(average). The time to reach the maximal E2 value of 32 h was the only pharmacokinetic parameter which was identical for all three patches. Menorest produced the highest E2 bioavailability judged by the AUC0-96h = 3967.8 +/- 1651.8 pg/ml, C(average) = 41.3 +/- 21.3 pg/ml, Cmin = 36.8 +/- 8.6 pg/ml. Tradelia showed statistically not significantly smaller C(average) = 38.9 +/- 17.0 pg/ml, AUC0-96h = 3737.9 +/- 1637.6 pg/ml x per h, and Cmin = 33.8 +/- 26.7 than Menorest. Estraderm MX showed lowest E2 plasma profiles Cmax = 38.9 +/- 25.1 pg/ml, C(average) = 33.2 +/- 17.1 pg/ml, AUC0-96 = 3192.1 +/- 1646.0 pg/ml per x h. Menorest showed the smallest fluctuation over the entire test period, similar to Estraderm MX, while Tradelia showed the highest E2-fluctuation (P < 0.01): Tradelia exhibited the highest Cmax = 48.0 +/- 20.3 pg/ml. When E2 baseline levels, prior to patch application are subtracted individually from the produced E2 plasma level, Estraderm MX is not bioequivalent to Menorest (P < 0.05). A circadian curve pattern of the E2 plasma level was observed for all patches: in the evening higher E2 plasma level were always detected compared with the morning, however, less pronounced with Estraderm MX. Individual comparison of AUC0-96h of each patch exhibited a large interindividual variability of 2000-8000 pg/ml per h for all three patches but relatively small individual variability: women with high E2 bioavailability (high responders) maintained high bioavailability in all applied patches, women identified as low and medium responders remained the same regardless of the applied patch. Menorest produced in 2/3 of all postmenopausal women with the highest E2 bioavailability (AUC0-96h), Tradelia was found in less than 1/3 (28.6%), and Estraderm MX in only one postmenopausal woman. Menorest only produced the highest reduction in postmenopausal symptoms together with Tradelia. Estraderm MX produced a smaller reduction in postmenopausal symptoms compared to Menorest and Tradelia. The observed side-effects were approximately equal in all three patches, with a maximum value after 72 h. It can be concluded that the three patches for the transdermal delivery of E2 claiming to deliver 50 microg E2/day differed from each other in their pharmacokinetic performance, although statistically not significant: Menorest exhibited the highest C(average), AUC and Cmin, and the lowest fluctuation, followed by Tradelia and Estraderm MX. PMID:10585173

Rohr, U D; Nauert, C; Stehle, B

1999-09-24

40

Effects of 17beta-estradiol, 4-nonylphenol and PCB 126 on the estrogenic activity and phase 1 and 2 biotransformation enzymes in male sea bass (Dicentrarchus labrax).  

PubMed

The endocrine system of wildlife is exposed to a wide variety of natural and man-made chemicals which may lead to damage to the reproductive system and other adverse effects, including alteration of drug-metabolizing enzymes. In the present study, the effects of in vivo exposure to a natural (17beta-estradiol: E2) or a xenoestrogen (4-nonylphenol: NP) estrogen or an anti-estrogen (3,3',4,4',5-pentachlorobiphenyl: PCB 126) upon vitellogenin (VTG) synthesis and hepatic phase 1 and 2 enzymes have been investigated in adult male sea bass. By means of ELISA analysis with the use of polyclonal antibodies prepared against VTG purified from E2-treated sea bass, we assessed the time course and sensitivity of VTG induction in the plasma of sea bass treated with E2 at 0.1, 0.5, 2.5 and 5.0 mg/kg doses or NP at 5.0 or 50 mg/kg doses, respectively. Sea bass sensitivity to this induction was found to be similar to that of other fish species, but with a delay in maximal response. E2 treatment also caused a selective time- and dose-dependent inhibition of hepatic CYP1A-linked EROD and phase 2 glutathione S-transferase (GST) activities, without affecting the activity of CYP3A-linked 6beta-testosterone hydroxylase, (omega)- and (omega-1)-lauric acid hydroxylases or phase 2 DT-diaphorase. A similar selective inhibition on CYP1A was also observed in fish treated with 50 mg/kg NP. The results regarding CYP1A and CYP3A were also confirmed by Western blot analysis. When the sea bass were treated with either 10 or 100 microg/kg PCB 126, an AhR ligand not yet tested in vivo in fish to assess its anti-estrogenicity, a modest and selective induction of EROD and DT-diaphorase activities was observed. Interestingly, both these activities were recovered to their control levels in sea bass co-treated with 0.5 mg/kg E2 and 10 or 100 microg/kg PCB 126, probably through a cross-talk mechanism between the estrogen receptor and AhR or other transcription factors that regulate the expression of these enzymes. Furthermore, it was demonstrated that PCB 126 possesses a potent anti-estrogenic activity in the sea bass in vivo as it inhibited the E2-induced VTG synthesis with an IC50 of 28 microg/kg. The results of this study suggest that the exposure of fish to xenoestrogens or anti-estrogens may alter, in addition to various physiological processes, the expression of specific CYPs and phase 2 enzymes, thereby reducing the capability of their detoxication system. PMID:16219370

Vaccaro, Emilia; Meucci, Valentina; Intorre, Luigi; Soldani, Giulio; Di Bello, Domenica; Longo, Vincenzo; Gervasi, Pier Giovanni; Pretti, Carlo

2005-11-30

41

High-density lipoprotein-associated 17beta-estradiol fatty acyl ester uptake by Fu5AH hepatoma cells: implications of the roles of scavenger receptor class B, type I and the low-density lipoprotein receptor.  

PubMed

17beta-estradiol (E2) fatty acyl esters naturally incorporate into high-density lipoprotein (HDL). The objective was to elucidate mechanisms involved in HDL-associated E2 cellular uptake and to determine the intracellular distribution of E2 and its fatty acyl esters (E2-FAE) after uptake. [3H]E2 or [3H] cholesterol was incubated with human serum for 24 h to allow for fatty acyl esterification. Total-HDL containing [3H]E2-FAE or [3H]cholesterol esters was isolated by sequential density ultracentrifugation and then incubated with Fu5AH rat hepatoma cells for various time points. Cellular uptake was determined by intracellular radioactivity as a percentage of total radioactivity. Chemical inhibition of scavenger receptor class B, type I and low-density lipoprotein (LDL) receptor competition assays were performed to determine cellular uptake mechanisms. Compared to HDL-[3H]cholesterol, cellular uptake of HDL-[3H]E2 occurred at an initially rapid rate. SR-BI inhibition resulted in a decrease in HDL-E2 uptake and LDL impaired this uptake in a concentration-dependent manner. Accordingly, pretreatment of cells with BLT-1 combined with LDL addition significantly attenuated HDL-E2 uptake. HDL-E2-FAE was hydrolyzed into free E2 with the maximum at 24 h. Fu5AH cells facilitate HDL-E2 uptake by at least SR-BI and LDL receptor pathways and intracellular hydrolysis of E2-FAE into free E2 ensues. PMID:17905649

Badeau, Robert M; Metso, Jari; Tikkanen, Matti J; Jauhiainen, Matti

2007-10-01

42

GEMS (Gene Expression MetaSignatures), a Web resource for querying meta-analysis of expression microarray datasets: 17beta-estradiol in MCF-7 cells.  

PubMed

With large amounts of public expression microrray data being generated by multiple laboratories, it is a significant task for the bench researcher to routinely identify available datasets, and then to evaluate the collective evidence across these datasets for regulation of a specific gene in a given system. 17beta-Estradiol stimulation of MCF-7 cells is a widely used model in the growth of breast cancer. Although myriad independent studies have profiled the global effects of this hormone on gene expression in these cells, disparate experimental variables and the limited power of the individual studies have combined to restrict the agreement between them as to the specific gene expression signature elicited by this hormone. To address these issues, we have developed a freely accessible Web resource, Gene Expression MetaSignatures (GEMS) that provides the user a consensus for each gene in the system. We conducted a weighted meta-analysis encompassing over 13,000 genes across 10 independent published datasets addressing the effect of 17beta-estradiol on MCF-7 cells at early (3-4 hours) and late (24 hours) time points. In a literature survey of 58 genes previously shown to be regulated by 17beta-estradiol in MCF-7 cells, the meta-analysis combined the statistical power of the underlying datasets to call regulation of these genes with nearly 85% accuracy (false discovery rate-corrected P < 0.05). We anticipate that with future expression microarray dataset contributions from investigators, GEMS will evolve into an important resource for the cancer and nuclear receptor signaling communities. PMID:19117983

Ochsner, Scott A; Steffen, David L; Hilsenbeck, Susan G; Chen, Edward S; Watkins, Christopher; McKenna, Neil J

2009-01-01

43

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

PubMed

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

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

1997-11-01

44

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

45

[Percentage of plasma protein-bound and free 17-beta-estradiol, progesterone and testosterone during the sexual cycle and during pregnancy in cows].  

PubMed

Examined were 12 cows with normal sexual cycle and other 12 cows in the last 20 days of pregnancy, all animals belonging to the Black-Pied breed. It was found that plasma protein bound 17-beta estradiol, progesteron, and testosteron during the sexual cycle were 94.726 +/- 0.076, 94-500 +/- 0.125 and 94.122 +/- 0.066 per cent, respectively. In the last twenty days of pregnancy these values rose - 96.911 +/- 0.058, 96.124 +/- 0.074, and 96.040 +/- 0.115, respectively. In testing the binding capacity of the bovine serum albumin it was found that it fixed almost 100 per cent the three ovarial hormones, while the bovine alpha, beta- and gamma-globulin's capacity in this respect was expressed in a negligible percent. PMID:75605

Kunchev, L

1977-01-01

46

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

47

17beta-estradiol pretreatment reduces CA1 sector cell death and the spontaneous hyperthermia that follows forebrain ischemia in the gerbil.  

PubMed

Pretreatment with 17beta-estradiol attenuates ischemia-induced hippocampal cornu ammonis 1 (CA1) neuronal death. We assessed whether this is mediated through prevention of hyperthermia that normally follows ischemia in gerbils. Male gerbils were given sustained-released 17beta-estradiol pellets or sham operation. Later, a guide cannula was implanted for brain temperature measurement and some were implanted with core temperature telemetry probes. Gerbils were subjected to either 5 min bilateral carotid artery occlusion or sham procedures 2 weeks after pellet surgery. Brain temperature was normothermic during surgery in all cases. In experiment 1, only core temperature was measured afterward in untreated and estrogen-treated gerbils. In experiment 2, postischemic core temperature was measured in untreated and two estrogen-treated ischemic groups, one of which had their postischemic temperature increased, via infrared lamp, to mimic the untreated group. Habituation was assessed on days 5 and 6. Hyperthermia, like that which occurs spontaneously, was forced on untreated and estrogen-treated ischemic animals in the third experiment, where brain temperature was measured. CA1 cell counts were assessed after a 7-day survival. A fourth experiment measured brain and core temperature simultaneously in normal gerbils during heating with an infrared lamp. Estrogen did not affect core temperature of non-ischemic gerbils whereas spontaneous postischemic hyperthermia was blocked. Estrogen reduced cell death and provided behavioral protection when gerbils regulated their own core temperature, but not when core hyperthermia was enforced. Conversely, estrogen reduced cell death in gerbils that had their brain temperature elevated. Experiment 4 showed that the brain becomes overheated (by approximately 1 degree C) when core temperature is elevated. Accordingly, estrogen likely failed to reduce CA1 injury in experiment 2, when core hyperthermia was enforced, because of overheating the brain. In conclusion, estrogen reduces CA1 cell death by mechanisms other than preventing hyperthermia. Our results also suggest that future studies regulate brain instead of body temperature. PMID:15489041

Plahta, W C; Clark, D L; Colbourne, F

2004-01-01

48

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

49

17 Beta-Estradiol Differentially Affects Left Ventricular and Cardiomyocyte Hypertrophy Following Myocardial Infarction and Pressure Overload  

PubMed Central

Background We have shown previously that 17?-estradiol (E2) increases left ventricular (LV) and cardiomyocyte hypertrophy following myocardial infarction (MI). However, E2 decreases hypertrophy in pressure overload models. We hypothesized that the effect of estrogen on cardiac hypertrophy was dependent on the type of hypertrophic stimulus. Methods Ovariectomized wild type female mice (n=192) were given vehicle or E2 treatment followed by coronary ligation (MI), transverse aortic constriction (TAC), or sham operation. Signaling pathway activation was studied at 3, 24, and 48 hours while echocardiography and hemodynamic studies were performed at 14 days. Results MI induced early but transient activation of p38 and p42/44 MAPK pathways, whereas TAC induced sustained activation of both pathways. E2 had no effect on these pathways, but increased Stat3 activation following MI while decreasing Stat3 activation following TAC. MI caused LV dilation, and decreased fractional shortening (FS), that were unaltered by E2. TAC caused LV dilation, reduced FS, and increased LV mass, but in this model, E2 improved these parameters. Following MI, E2 led to increases in myocyte cross-sectional area, atrial natriuretic peptide (ANP) and ?-myosin heavy chain (MHC) gene expression, but E2 diminished TAC-induced increases ANP and ?-MHC gene expression. Conclusions These data demonstrate that the effects of E2 on LV and myocyte remodeling depend on the nature of the hypertrophic stimulus. The opposing influence of E2 on hypertrophy in these models may, in part, result from differential effects of E2 on Stat3 activation. Further work will be necessary to explore this and other potential mechanisms by which estrogen affects hypertrophy in these models. PMID:18381189

Patten, Richard D.; Pourati, Isaac; Aronovitz, Mark J.; Alsheikh-Ali, Alawi; Eder, Sarah; Force, Thomas; Mendelsohn, Michael E.; Karas, Richard H.

2014-01-01

50

17Beta-estradiol promotes aggressive laryngeal cancer through membrane-associated estrogen receptor-alpha 36.  

PubMed

17?-estradiol (E2) plays a key role in tumorigenesis by enhancing cell survivability and metastasis through its cytoplasmic receptors. Recently, a variant of estrogen receptor alpha, ER?36 has been implicated as a substantial mediator of E2's proliferative and antiapoptotic effects through rapid membrane-associated signaling, and cancers previously regarded as hormone-independent due to the absence of traditional receptors, may in fact be susceptible to E2. Despite rising from a secondary sex organ and having a clear gender disposition, laryngeal cancer is not uniformly accepted as hormone dependent, even in the face of compelling evidence of E2 responsiveness. The aim of this study was to further elucidate the role of E2 in the tumorigenesis of laryngeal cancer, both in vitro and in vivo. ER?36 presence was evaluated in membranes of the laryngeal carcinoma cell line, Hep2, as well as in laryngeal tumor samples. In vitro ER?36 was found to mediate rapid activation of protein kinase C and phospholipase D by E2, leading to increased proliferation and protection against chemotherapy-induced apoptosis. Furthermore, in response to E2 activation of ER?36, an upregulation of angiogenic and metastatic factors was observed. Clinical analysis of laryngeal tumors revealed a similar association between the amount of ER?36 and VEGF and indicated a role in lymph node metastasis. These findings present compelling evidence of ER?36-dependent E2 signaling in laryngeal cancer. Thus, targeting ER?36 may reduce the deleterious effects of E2 in laryngeal cancer, ultimately suggesting the importance of antiestrogen therapy or the production of novel drugs that specifically target ER?36. PMID:24081562

Schwartz, Nofrat; Chaudhri, Reyhaan A; Hadadi, Agreen; Schwartz, Zvi; Boyan, Barbara D

2014-02-01

51

Analyses of the effects of 17beta-estradiol on skeletal muscle and global gene expression following acute eccentric exercise  

Microsoft Academic Search

Introduction: l7?-estradiol (E2) has proposed anti-oxidant and membrane stabilizing properties that may attenuate exercise-induced damage, inflammation and alter gene expression. The purpose of this thesis was to determine if acute E2 supplementation would affect the oxidative stress, membrane damage, inflammation and global mRNA expression induced by eccentric exercise. ^ Methods: 18 healthy young males were randomly assigned to 8 days

Lauren G MacNeil

2010-01-01

52

Immunohistological localization of 17 beta-estradiol and testosterone in the ovary of the rainbow trout (Salmo gairdneri Richardson) during the preovulatory period.  

PubMed

Antisera (AS) raised in rabbits against 17 beta-estradiol (E) and testosterone (T) were tested for their suitability to localize E and T on deparaffinized, rehydrated sections of preovulatory trout ovaries, using the unlabeled antibody technique. Conventional control experiments demonstrated the specificity of the staining reactions. Furthermore, no staining was observed after the removal of T-specific antibodies by affinity chromatography, or following gonadectomy when non-gonadal tissue sections of male trout were incubated with T-AS. Antiserum, raised against 11-oxotestosterone and devoid of antibodies cross-reacting with T, did not stain ovarian sections. The loci at which E and T are detected in the somatic compartment are consistent with the two-cell concept of estrogen synthesis, where aromatizable androgens are produced in the thecal/interstitial layer and serve as substrates for estrogen synthesis in granulosa cells. Both steroids were detected in yolk vesicles from the stage of endogenous vitellogenesis. T-AS showed affinity for nuclei of vitellogenic oocytes. Nucleoli were not stained. PMID:3530492

Schulz, R

1986-01-01

53

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

54

Hepatic estrogen receptor and plasma 17{beta}-estradiol concentrations as biomarkers of 2,3,7,8-TCDD exposure in avian hatchlings  

SciTech Connect

The authors have been investigating the sensitivity of various toxicologically relevant endpoints as environmental biomarkers in avian hatchlings exposed in ovo to 2,3,7,8-TCDD. Potential biomarkers included various endocrine endpoints such as plasma 17{beta}-estradiol (E{sub 2}), hepatic estrogen receptor (ER) affinities and concentrations, and plasma thyroid hormones, which were compared to hepatic ethoxyresorufin O-deethylase (EROD) induction. The animal models used were domestic chickens and pigeons, and great blue herons. An experiment conducted in pigeon hatchlings compared ``early`` (embryonic day 4; E4) vs. ``late`` (E14) in ovo exposure to 1 {micro}g/kg and 3 {micro}g/kg of TCDD, respectively. Birds were sacrificed on day of hatch (H) and day 7 after hatch (D7). In the late exposure experiment, plasma E{sub 2} concentrations were reduced at H and elevated at D7 in the TCDD-exposed birds (p < 0.05). Hepatic ER concentrations were elevated at H (p < 0.01). Although EROD was half-maximally induced at H and D7 in the early exposure experiment in pigeons, there was no effect of TCDD treatment on E, or ER levels. The nominal TCDD concentration in these pigeons (1 {micro}g/kg egg) was within the range observed in wild piscivorous bird eggs collected from aquatic systems contaminated with TCDD and related chemicals (approx. 0.5--2 ng TEQ/g egg). In herons exposed to 2 {micro}g/kg of TCDD at the midpoint of incubation, hepatic ER affinities (Kd) and concentrations (Bmax) were elevated in treated birds at H (p < 0.05); however there was no effect on plasma E, levels. Liver [{sup 3}H]-TCDD concentrations were 11.3 {+-} 0.8 ng/g at H, and 0.8 {+-} 0.1 ng/g at D7, representing 9.9% and 4.9% of the nominal TCDD dose, respectively.

Janz, D.M.; Bellward, G.D. [Univ. of British Columbia, Vancouver, British Columbia (Canada)

1995-12-31

55

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

56

Variations in maternal care alter corticosterone and 17beta-estradiol levels, estrous cycle and folliculogenesis and stimulate the expression of estrogen receptors alpha and beta in the ovaries of UCh rats  

PubMed Central

Background Variations in maternal care are associated with neonatal stress, hormonal disturbances and reproductive injuries during adulthood. However, the effects of these variations on sex hormones and steroid receptors during ovary development remain undetermined. This study aimed to investigate whether variations in maternal care are able to influence the hormonal profile, follicular dynamics and expression of AR, ER-alpha and ER-beta in the ovaries of UCh rat offspring. Methods Twenty-four adult UCh rats, aged 120 days, were randomly divided into two groups (UChA and UChB) and mated. Maternal care was assessed from birth (day 0) to the 10th postnatal day (PND). In adulthood, twenty adult female rats (UChA and UChB offspring; n = 10/group), aged 120 days, were euthanized by decapitation during the morning estrus. Results UChA females (providing high maternal care) more frequently displayed the behaviors of carrying pups, as well as licking/grooming and arched back nursing cares. Also, mothers providing high care had elevated corticosterone levels. Additionally, offspring receiving low maternal care showed the highest estrous cycle duration, increased corticosterone and 17beta-estradiol levels, overexpression of receptors ER-alpha and ER-beta, increased numbers of primordial, antral and mature follicles and accentuated granulosa cell proliferation. Conclusions Our study suggests that low maternal care alters corticosterone and 17beta-estradiol levels, disrupting the estrous cycle and folliculogenesis and differentially regulating the expression of ER-alpha and ER-beta in the ovaries of adult rats. PMID:22192617

2011-01-01

57

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 ...

58

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

59

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...

60

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

USGS Publications Warehouse

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

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

1997-01-01

61

The proximal promoter of the bovine luteinizing hormone beta-subunit gene confers gonadotrope-specific expression and regulation by gonadotropin-releasing hormone, testosterone, and 17 beta-estradiol in transgenic mice.  

PubMed

Transient transfection studies have proven useful in unraveling the molecular mechanisms underlying gonadotrope-specific expression and hormonal regulation of the gene encoding the alpha-subunit of the glycoprotein hormones. In contrast, similar studies performed with the LH beta gene have been less informative. When assayed by transient transfection into alpha T3-1 cells, activity of a 776-basepair bovine LH beta promoter-chloramphenicol acetyltransferase fusion gene (bLH beta CAT) was no greater than that of a promoterless control. To determine whether limited activity in vitro reflected the absence of critical regulatory elements, we examined activity of bovine LH beta fusion genes after stable integration in transgenic mice. In contrast to transient transfection studies, the LH beta promoter targeted high levels of CAT expression specifically to the pituitary. In addition, a bLH beta TK fusion gene was active only in gonadotropes. The bLH beta CAT transgene was also evaluated for responsiveness to gonadal steroids and GnRH. Testosterone and 17 beta-estradiol were capable of suppressing activity 70-80% in castrated males, despite the absence of high affinity binding sites for androgen or estrogen receptors. This suggests that feedback inhibition of LH beta CAT transgene expression by gonadal steroids may occur through an indirect mechanism, possibly at the level of the hypothalamus. To address whether the bLH beta CAT transgene could be regulated by GnRH, we treated ovariectomized females with antide, a GnRH antagonist. Antide suppressed transgene activity by 60%. Thus, the proximal promoter of the bovine LH beta subunit gene directs appropriate patterns of cell-specific expression and retains responsiveness to gonadal steroids and GnRH. In light of the robust activity of the LH beta promoter in transgenic mice, we suggest that this animal model can be exploited further to dissect the complex mechanisms that underlie gonadotrope-specific expression and hormonal regulation of the LH beta gene. PMID:7708066

Keri, R A; Wolfe, M W; Saunders, T L; Anderson, I; Kendall, S K; Wagner, T; Yeung, J; Gorski, J; Nett, T M; Camper, S A

1994-12-01

62

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

63

Assessing the effects of exposure timing on biomarker expression using 17beta-estradiol  

EPA Science Inventory

Temporal and spatial variability in estrogenicity has been documented for many treated wastewater effluents with the consequences of this variability on the expression of biomarkers of endocrine disruption being largely unknown. Laboratory exposure studies usually utilize constan...

64

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

E-print Network

. Hypothetical scenarios, simulated using HYDRUS-1D, evaluated the combined effects of soil texture and the values obtained for sorption and mineralization on leaching. Model results indicated rapid leaching in loamy sand, while sandy clay loam and clay yielded...

Ullman, Jeffrey Layton

2007-09-17

65

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

E-print Network

University School of Medicine2 , Indiana University School of Medicine Department of Physical Therapy) is a devastating disease that is characterized by a rise of blood pressure in the blood vessels of the lung. This puts significant strain on the right ventricle (RV) of the heart. If untreated, PH can lead to right

Zhou, Yaoqi

66

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

Microsoft Academic Search

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

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

1997-01-01

67

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.

68

PROMOTION BY 17&BETA;-ESTRADIOL AND &BETA;-HEXACHLOROCYCLOHEXANE OF HEPATOCELLULAR TUMORS IN MEDAKA, ORYZIAS LATIPES. AQUAT. (R828676C002)  

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...

69

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...

70

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

EPA Science Inventory

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

71

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...

72

17-Beta-Estradiol Directly Regulates the Expression of Adrenergic Receptors and Kisspeptin\\/GPR54 System in GT1-7 GnRH Neurons  

Microsoft Academic Search

Estradiol plays a critical role in the feedback regulation of reproduction, in part by modulating the neurosecretory activity of gonadotropin-releasing hormone (GnRH) neurons. While indirect effects of estradiol on GnRH neurons have been clearly demonstrated, direct actions are still controversial. In the current study, we examined direct effects of 17?-estradiol upon the expression of receptors for afferent signals at the

Jessica S. Jacobi; Cecilia Martin; Gabriel Nava; Michael C. Jeziorski; Carmen Clapp; Gonzalo Martínez de la Escalera

2007-01-01

73

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...

74

17beta-Estradiol and testosterone in drainage and runoff from poultry litter applications to tilled and no-till crop land under irrigation.  

PubMed

Thirteen million [corrected] metric tons of poultry litter are produced annually by poultry producers in the U.S. Poultry litter contains the sex hormones estradiol and testosterone, endocrine disruptors that have been detected in surface waters. The objective of this study was to evaluate the potential impact of poultry litter applications on estradiol and testosterone concentrations in subsurface drainage and surface runoff in irrigated crop land under no-till and conventional-till management. We conducted an irrigation study in fall of 2001 and spring of 2002. Four treatments, no-till plus poultry litter, conventional-till plus poultry litter, no-till plus conventional fertilizer, and conventional-till plus conventional fertilizer, were evaluated. Flow-weighted concentration and load ha(-1) of the two hormones were measured in drainage and runoff. Soil concentrations of estradiol and testosterone were measured. Based on comparisons to the conventional fertilizer (and control) treatments, poultry litter did not add to the flow-weighted concentration or load ha(-1) of either estradiol or testosterone in subsurface drainage or surface runoff. Significant differences were, however, observed between tillage treatments: flow-weighted concentrations of estradiol were greater for no-till than conventional-till plots of the June irrigation; and runoff loads of both estradiol and testosterone were less from no-till than conventional-till plots for the November irrigation. Although the differences between no-till and conventional-tillage appeared to affect the hydrologic transport of both hormones, the differences appeared to have inconsequential environmental impact. PMID:19269082

Jenkins, Michael B; Endale, Dinku M; Schomberg, Harry H; Hartel, Peter G; Cabrera, Miguel L

2009-06-01

75

17beta -estradiol Regulates and v-Ha-ras Transfection Constitutively Enhances MCF7 Breast Cancer Cell Interactions with Basement Membrane  

Microsoft Academic Search

The interaction of a line of human breast carcinoma cells (MCF7) with basement membrane components, particularly laminin, was altered by exposure of the cells to estrogen as well as by transfection of the cells with the v-Ha-ras oncogene. In both cases, the cells show a greater ability to attach to a laminin substrate, to migrate to laminin, to grow in

Adriana Albini; Jeannette Graf; Gregory T. Kitten; Hynda K. Kleinman; George R. Martin; Andre Veillette; Marc E. Lippman

1986-01-01

76

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

77

Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients: evidence for an estrogen surface receptor.  

PubMed

We tested the hypothesis that estrogen acutely stimulates constitutive NO synthase (cNOS) activity in human peripheral monocytes by acting on an estrogen surface receptor. NO release was measured in real time with an amperometric probe. 17beta-estradiol exposure to monocytes stimulated NO release within seconds in a concentration-dependent manner, whereas 17alpha-estradiol had no effect. 17beta-estradiol conjugated to BSA (E2-BSA) also stimulated NO release, suggesting mediation by a membrane surface receptor. Tamoxifen, an estrogen receptor inhibitor, antagonized the action of both 17beta-estradiol and E2-BSA, whereas ICI 182,780, a selective inhibitor of the nuclear estrogen receptor, had no effect. We further showed, using a dual emission microfluorometry in a calcium-free medium, that the 17beta-estradiol-stimulated release of monocyte NO was dependent on the initial stimulation of intracellular calcium transients in a tamoxifen-sensitive process. Leeching out the intracellular calcium stores abolished the effect of 17beta-estradiol on NO release. RT-PCR analysis of RNA obtained from the cells revealed a strong estrogen receptor-alpha amplification signal and a weak beta signal. Taken together, a physiological dose of estrogen acutely stimulates NO release from human monocytes via the activation of an estrogen surface receptor that is coupled to increases in intracellular calcium. PMID:10490972

Stefano, G B; Prevot, V; Beauvillain, J C; Fimiani, C; Welters, I; Cadet, P; Breton, C; Pestel, J; Salzet, M; Bilfinger, T V

1999-10-01

78

1-10 nM E2 E2 30 E2  

E-print Network

076 1. E2 E2 E2 E2 2. E2 E2 2 E2 1 1-10 nM E2 5), 7) E2 30 E2 7) E2 512076-0792011 Modulation of Learning and Memory slowly but also rapidly. Slow actions of estradiol (E2) occur via nuclear receptors (ER), while rapid E2

Kawato, Suguru

79

Reproductive Toxicology 24 (2007) 178198 In vitro molecular mechanisms of bisphenol A action  

E-print Network

, diethylstilbesterol; DHT, dihydrotestosterone; DMSO, dimethyl sulfoxide; E2, 17beta-estradiol; EDC, endocrine g Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, United States h Biochemisty and Molecular Biology Department, University of Texas Medical Branch

McLachlan, John

80

Estrogen Therapy in a Viral Murine Model of Multiple Sclerosis  

E-print Network

17-beta-estradiol (E2) and estriol (E3) are at their highest levels. In order to study the role of estrogens as potential therapeutic agents for MS we investigated their role in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelination...

Gomez, Francisco Pascual

2012-10-19

81

Domain analysis for estrogen receptor/Sp1-mediated transactivation and detection of estrogen receptor/Sp1 protein interactions in living cells  

E-print Network

of ER? on activation of ER?/Sp1. 17Beta-estradiol (E2) and the antiestrogens 4-hydroxytamoxifen and ICI 182,780 induced reporter gene activity in MCF-7 and MDA-MB-231 cells cotransfected with human or mouse ER? (hER? or MOR), but not ER? and GC...

Kim, KyoungHyun

2005-11-01

82

A phorbol ester and calcium ionophore regulate sex steroid and prostaglandin release by follicles of the anuran Rana esculenta and the urodele Triturus carnifex.  

PubMed

The aim of this work was to study the relationships among protein kinase C (PKC), calcium, prostaglandins (PGs), and sex steroids in follicles of Rana esculenta and Triturus carnifex. Follicles, oocytes, and wall cells of follicle (theca and granulosa cells) were incubated in vitro with an activator of PKC, phorbol-12-myristate-13-acetate (PMA), a calcium ionophore (A23187), an antagonist of calcium channel, verapamil, PMA + A23187, prostaglandin F2 alpha (PGF2 alpha), and prostaglandin E2 (PGE2). Progesterone, androgens, and 17 beta-estradiol were assessed in incubation media of follicles and wall cells and PGs in incubation media of follicles, oocytes, and wall cells. In both species, PMA increased progesterone; A23187 increased progesterone, 17 beta-estradiol, and PGs; verapamil decreased progesterone and PGs; PMA + A23187 increased progesterone, 17 beta-estradiol, and PGs; PGF2 alpha increased 17 beta-estradiol; PGE2 increased progesterone. These data suggest that PKC and calcium intervene in the regulation of steroidogenesis and PG synthesis by follicles of both R. esculenta and T. carnifex; in particular, calcium seems to regulate PGs synthesis, activating an enzymatic pathway which does not include PKC. PMID:8138111

Gobbetti, A; Zerani, M

1994-01-01

83

The E(2) particle  

SciTech Connect

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

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

2009-12-15

84

Alteration of the hypothalamic-pituitary-gonadal axis in estrogen- and androgen-treated adult male leopard frog, Rana pipiens  

Microsoft Academic Search

BACKGROUND: Gonadal steroids, in particular 5 alpha-dihydrotestosterone (DHT) and 17 beta-estradiol (E2), have been shown to feed back on the hypothalamic-pituitary-gonadal (HPG) axis of the ranid frog. However, questions still remain on how DHT and E2 impact two of the less-studied components of the ranid HPG axis, the hypothalamus and the gonad, and if the feedback effects are consistently negative.

Pei-San Tsai; Ann E Kessler; Jeremy T Jones; Kathleen B Wahr

2005-01-01

85

EFFECT OF ESTROGENIC ACTIVITY IN RIVER WATER AND TREATED WASTEWATER ON FEMINIZATION OF  

Microsoft Academic Search

The objective of the study is to evaluate the effect of estrogens in river water and treated wastewater on fish feminization. Male Japanese Medaka (Oryzias latipes) was used for exposure test of various concentrations of estrone (E1) or 17beta-estradiol (E2), river water and treated wastewater. Generation of vitellogenin in the liver of male Medaka was measured as the index of

JAPANESE MEDAKA; Kiyoaki Kitamura; Koya Komori; Kiyoshi Miyajima; Tadashi Higashitani; Norihide Nakada; Yutaka Suzuki

86

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

87

Aspirin inhibits androgen response to chorionic gonadotropin in humans.  

PubMed

Eicosanoids play an important role in the regulation of the hypothalamic-pituitary axis; less clear is their role in testicular steroidogenesis. To evaluate the involvement of cyclooxygenase metabolites, such as prostaglandins, in the regulation of human testicular steroidogenesis, we examined the effects of a prostaglandin-blocker, aspirin, on plasma testosterone, pregnenolone, progesterone, 17OH-progesterone, androstenedione, dehydroepiandrosterone, and 17beta-estradiol response to human chorionic gonadotropin (hCG) in normal male volunteers in a placebo-controlled, single-blinded study. To test the efficacy of aspirin, seminal prostaglandin E(2) levels were also determined. hCG stimulation increased peripheral levels of testosterone, 17OH-progesterone, androstenedione, dehydroepiandrosterone, and 17beta-estradiol, without affecting circulating pregnenolone and progesterone values. Aspirin significantly lowered seminal prostaglandin E(2) levels, whereas it did not modify steroid concentrations not exposed to exogenous hCG. Moreover, the drug significantly reduced the response of testosterone, 17OH-progesterone, androstenedione, and dehydroepiandrosterone to hCG, as assessed by the mean integrated area under the curve, whereas it did not influence 17beta-estradiol response. In conclusion, aspirin treatment inhibits androgen response to chorionic gonadotropin stimulation in normal humans. The action of aspirin is probably mediated via an effective arachidonate cyclooxygenase block. PMID:10600792

Conte, D; Romanelli, F; Fillo, S; Guidetti, L; Isidori, A; Franceschi, F; Latini, M; di Luigi, L

1999-12-01

88

Molecular mechanism of inhibition of estrogen-induced cathepsin D gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in MCF-7 cells  

SciTech Connect

This report describes how 17{beta}-estradiol (E2) induces cathepsin D gene expression, but is inhibited by the aryl hydrocarbon receptor by disruption of the estrogen receptor/pBC12/S1/pac plasmid complex by interaction with an overlapping xenobiotic responsive element. It was also determined that 2,3,7,8-tetrachlorobenzo-p-dioxin (TCDD) alone does not affect cathepsin D gene expression but can together with E2 to affect the rate of transcription and levels of immunoreactive protein. 85 refs., 6 figs., 2 tabs.

Krishnan, V.; Porter, W.; Santostefano, M.; Wang, Xiahong [Texas A& M Univ., College Station, TX (United States)] [and others

1995-12-01

89

Moist convection scheme in Model E2  

E-print Network

This documentation describes the version of the Del Genio - Yao cumulus parameterization used in the NASA Goddard Institute for Space Studies Model E2 GCM. This version was used for the official GISS submissions to the CMIP5 archive.

Kim, Daehyun; Yao, Mao-Sung

2013-01-01

90

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

91

E2E: A Summary of the e2e Learning Framework.  

ERIC Educational Resources Information Center

This publication is a summary of the E2E (Entry to Employment) Learning Framework that provides guidance on program implementation. (E2E is a new learning program for young people not yet ready or able to enter Modern Apprenticeship programs, a Level 2 program, or employment directly.) Section 2 highlights core values to which all involved should…

Learning and Skills Development Agency, London (England).

92

Nuclear localization of prostaglandin E2 receptors  

PubMed Central

Prostaglandin E2 receptors (EP) were detected by radioligand binding in nuclear fractions isolated from porcine brain and myometrium. Intracellular localization by immunocytofluorescence revealed perinuclear localization of EPs in porcine cerebral microvascular endothelial cells. Nuclear association of EP1 was also found in fibroblast Swiss 3T3 cells stably overexpressing EP1 and in human embryonic kidney 293 (Epstein–Barr virus-encoded nuclear antigen) cells expressing EP1 fused to green fluorescent protein. High-resolution immunostaining of EP1 revealed their presence in the nuclear envelope of isolated (cultured) endothelial cells and in situ in brain (cortex) endothelial cells and neurons. Stimulation of these nuclear receptors modulate nuclear calcium and gene transcription. PMID:9861049

Bhattacharya, Mousumi; Peri, Krishna G.; Almazan, Guillermina; Ribeiro-da-Silva, Alfredo; Shichi, Hitoshi; Durocher, Yves; Abramovitz, Mark; Hou, Xin; Varma, Daya R.; Chemtob, Sylvain

1998-01-01

93

Anomalously hindered E2 strength B(E2;2_1^+ -> 0^+) in 16C  

E-print Network

The electric quadrupole transition from the first 2+ state to the ground 0+ state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured lifetime is 75 +- 23 ps, corresponding to a B(E2;2_1+ -> 0^+) value of 0.63 +- 0.19 e2fm4, or 0.26 +- 0.08 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.

N. Imai; N. Aoi; N. Fukuda; T. Kishida; T. Kubo; T. Minemura; T. Motobayashi; S. Takeuchi; K. Yoneda; H. Watanabe; M. Ishihara; H. J. Ong; H. Sakurai; H. Iwasaki; T. K. Ohnishi; M. K. Suzuki; K. Demichi; H. Kawasaki; H. Baba; T. Gomi; H. Hasegawa; E. Kaneko; S. Kanno; K. Kurita; E. Takeshita; A. Saito; Zs. Dombradi; Z. Elekes; Zs. Fulop; A. Gelberg; K. Ishikawa; Y. Kondo; M. Miura; T. Nakamura; T. Sugimoto; S. Michimasa; M. Notani; S. Shimoura; M. Tamaki

2003-09-30

94

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

, government/industry, public/private collaborative program to assess and demonstrate the feasibilityE2I 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

95

17?-estradiol and inflammation: implications for ischemic stroke.  

PubMed

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

2014-10-01

96

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.

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

2014-01-01

97

E2C mechanism in elimination reactions. VI. Primary hydrogen isotope effects on rates of E2 reactions of alicyclics  

Microsoft Academic Search

Primany hydrogen isotope effects on the rates of bimolecular elimination ; reactions of some cyclohexyl tosylates and bromides are small (k\\/sup H\\/k\\/sup D\\/ ; approximately 2 -3) for very E2C-like reactions, pass through a maximum of 6 for ; more E2H-like reactions, and are small again (2 -- 3) for very E2H-like reactions. ; Movement from the E2C to the

David Cook; R. E. J. Hutchinson; J. K. MacLeod; A. J. Parker

1974-01-01

98

Functional roles of E2F in cell cycle regulation  

Microsoft Academic Search

The E2F family of transcription factors play a key role in G1-S progression. A dominant negative mutant (E2F97) of E2F1 containing the DNA binding domain of E2F1 under the control of a tetracycline-responsive promoter was constructed. Stable transfectants were produced in the pRb-lacking SaOS-2 cell line and SV40-transformed VA-13 cell line, respectively. Induction of E2F97 by tetracycline withdrawal resulted in

Jianguo Fan; Joseph R Bertino; JR Bertino

1997-01-01

99

Interplay between Arabidopsis Activating Factors E2Fb and E2Fa in Cell Cycle Progression and Development1[W  

PubMed Central

Eukaryotic E2Fs are conserved transcription factors playing crucial and antagonistic roles in several pathways related to cell division, DNA repair, and differentiation. In plants, these processes are strictly intermingled at the growing zone to produce postembryonic development in response to internal signals and environmental cues. Of the six AtE2F proteins found in Arabidopsis (Arabidopsis thaliana), only AtE2Fa and AtE2Fb have been clearly indicated as activators of E2F-responsive genes. AtE2Fa activity was shown to induce S phase and endoreduplication, whereas the function of AtE2Fb and the interrelationship between these two transcription factors was unclear. We have investigated the role played by the AtE2Fb gene during cell cycle and development performing in situ RNA hybridization, immunolocalization of the AtE2Fb protein in planta, and analysis of AtE2Fb promoter activity in transgenic plants. Overexpression of AtE2Fb in transgenic Arabidopsis plants led to striking modifications of the morphology of roots, cotyledons, and leaves that can be ascribed to stimulation of cell division. The accumulation of the AtE2Fb protein in these lines was paralleled by an increased expression of E2F-responsive G1/S and G2/M marker genes. These results suggest that AtE2Fa and AtE2Fb have specific expression patterns and play similar but distinct roles during cell cycle progression. PMID:16514015

Sozzani, Rosangela; Maggio, Caterina; Varotto, Serena; Canova, Sabrina; Bergounioux, Catherine; Albani, Diego; Cella, Rino

2006-01-01

100

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; Clape, Cyrielle; Chavey, Carine; Fritz, Vanessa; Casas, Francois; Apparailly, Florence; Auwerx, Johan; Fajas, Lluis

2013-01-01

101

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

PubMed Central

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

2013-01-01

102

Reproductive responses of common carp (Cyprinus carpio) exposed in cages to influent of the Las Vegas Wash in Lake Mead, Nevada, from late winter to early spring.  

PubMed

The Las Vegas Wash (LW) delivers tertiary-treated municipal wastewater effluent, nonpotable shallow groundwater seepage, and runoff from the urbanized Las Vegas Valley to Las Vegas Bay (LX) of Lake Mead. To investigate the potential for contaminants in LW influent to produce effects indicative of endocrine disruption in vivo, adult male and female common carp (Cyprinus carpio) were exposed in cages for 42-48 d at four sites in Lake Mead: LW, LX, and two reference locations in the lake. End points examined included gonadosomatic index; gonad histology; concentrations of plasma vitellogenin (VTG) and plasma sex steroids (17beta-estradiol (E2), testosterone (T), 11-ketotestosterone (11-KT)); plasma estrogen:androgen ratios (E2:T, E2:11-KT), in vitro production of T by gonad tissue, and hepatopancreas ethoxyresorufin O-deethylase activity. Few differences among fish caged at different sites were potentially attributable to exposure to contaminants PMID:15597896

Snyder, Erin M; Snyder, Shane A; Kelly, Kevin L; Gross, Timothy S; Villeneuve, Daniel L; Fitzgerald, Scott D; Villalobos, Sergio A; Giesy, John P

2004-12-01

103

New plant vectors for protein tagging with E2 epitope  

Microsoft Academic Search

E2Tag has been used for tagging of bacterial, yeast, and mammalian proteins. A set of plant expression vectors was constructed\\u000a for tagging proteins with E2Tag. Detection of E2-tagged proteins with specific antibodies inNicotiana benthamiana andNicotiana tabacum was easily done without any nonspecific background activity. No effect on the biological activity of the enzyme GUS, used\\u000a as a marker, was detected.

Lenne Nigul; Allan Olspert; Merike Meier; Heiti Paves; Tiit Talpsep; Erkki Truve

2004-01-01

104

Constraining the $(?, ?)$ amplitudes for E2 $N \\to ?$  

E-print Network

We reply to the Comment of A.M. Sandorfi et al. [nucl-th/9707028] on the E2/M1 ratio from the Mainz photoproduction data, nucl-th/9707028 v2. We support our published result for the E2/M1 ratio of REM = -(2.5 +- 0.2 +- 0.2)%.

R. Beck; H. P. Krahn

1997-07-29

105

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

106

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

107

Developing a biosensor for estrogens in water samples: study of the real-time response of live cells of the estrogen-sensitive yeast strain RMY/ER-ERE using fluorescence microscopy.  

PubMed

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 (ERalpha) gene and the lacZ gene which encodes beta-galactosidase, the uptake of 17beta-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. PMID:16143503

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

2006-02-15

108

E2F and microRNA regulation of angiogenesis  

PubMed Central

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

Biyashev, Dauren; Qin, Gangjian

2011-01-01

109

NEDDylation regulates E2F-1-dependent transcription  

PubMed Central

The ubiquitin-like molecule NEDD8 modifies cullin-RING ubiquitin E3 ligases. NEDD8 has been shown to have a few additional substrates, but the extent to which this modification targets non-cullins and the functional significance of such modifications remain unclear. Here, we demonstrate that the cell-cycle-regulating transcription factor E2F-1 is a substrate for NEDD8 post-translational modification. NEDDylation results in decreased E2F-1 stability, lower transcriptional activity and slower cell growth. The lysine residues in E2F-1 targeted for NEDDylation can also be methylated, pointing to a possible interplay between these modifications. These results identify a new mode of E2F-1 regulation and highlight the emerging role of NEDD8 in regulating transcription factor stability and function. PMID:22836579

Loftus, Sarah J; Liu, Geng; Carr, Simon M; Munro, Shonagh; La Thangue, Nicholas B

2012-01-01

110

E2F6 in axial skeletal development and gliosis  

E-print Network

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

Friesenhahn, Laurie Beth

2008-01-01

111

Immunoglobulin mimicry by Hepatitis C Virus envelope protein E2  

Microsoft Academic Search

Hepatitis C virus (HCV) establishes persistent infection in the majority of infected individuals. The currently accepted hypothesis of immune evasion by antigenic variation in hypervariable region 1 (HVR1) of glycoprotein E2 does not however, explain the lack of subsequent immune recognition. Here, we show that the N-terminal region of E2 is antigenically and structurally similar to human immunoglobulin (Ig) variable

Yu-Wen Hu; Lynda Rocheleau; Bryce Larke; Linda Chui; Bonita Lee; Mang Ma; Song Liu; Teye Omlin; Martin Pelchat; Earl G. Brown

2005-01-01

112

Sibling rivalry in the E2F family.  

PubMed

The E2F transcription factor family determines whether or not a cell will divide by controlling the expression of key cell-cycle regulators. The individual E2Fs can be divided into distinct subgroups that act in direct opposition to one another to promote either cellular proliferation or cell-cycle exit and terminal differentiation. What is the underlying molecular basis of this 'push-me-pull-you' regulation, and what are its biological consequences? PMID:11823794

Trimarchi, Jeffrey M; Lees, Jacqueline A

2002-01-01

113

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

PubMed Central

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

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

2012-01-01

114

Large Scale Genotype Comparison of Human Papillomavirus E2-Host Interaction Networks Provides New Insights for E2 Molecular Functions  

PubMed Central

Human Papillomaviruses (HPV) cause widespread infections in humans, resulting in latent infections or diseases ranging from benign hyperplasia to cancers. HPV-induced pathologies result from complex interplays between viral proteins and the host proteome. Given the major public health concern due to HPV-associated cancers, most studies have focused on the early proteins expressed by HPV genotypes with high oncogenic potential (designated high-risk HPV or HR-HPV). To advance the global understanding of HPV pathogenesis, we mapped the virus/host interaction networks of the E2 regulatory protein from 12 genotypes representative of the range of HPV pathogenicity. Large-scale identification of E2-interaction partners was performed by yeast two-hybrid screenings of a HaCaT cDNA library. Based on a high-confidence scoring scheme, a subset of these partners was then validated for pair-wise interaction in mammalian cells with the whole range of the 12 E2 proteins, allowing a comparative interaction analysis. Hierarchical clustering of E2-host interaction profiles mostly recapitulated HPV phylogeny and provides clues to the involvement of E2 in HPV infection. A set of cellular proteins could thus be identified discriminating, among the mucosal HPV, E2 proteins of HR-HPV 16 or 18 from the non-oncogenic genital HPV. The study of the interaction networks revealed a preferential hijacking of highly connected cellular proteins and the targeting of several functional families. These include transcription regulation, regulation of apoptosis, RNA processing, ubiquitination and intracellular trafficking. The present work provides an overview of E2 biological functions across multiple HPV genotypes. PMID:22761572

Muller, Mandy; Jacob, Yves; Jones, Louis; Weiss, Amelie; Brino, Laurent; Chantier, Thibault; Lotteau, Vincent; Favre, Michel; Demeret, Caroline

2012-01-01

115

[Partial deficiency in 21-hydroxylase in certain forms of hirsutism].  

PubMed

The ACTH test is important when hirsutism occurs in women with a slight 21-hydroxylase deficiency, and normal basal 17-OH Progesterone (17-OH-P/plasma levels). Extensive hormonal assays: LH, FSH, Prolactin, 17 beta-estradiol (E2), Estrone, 17OH-P, Androstenedione, Testosterone, Cortisol (C), Dehydroepiandrosterone-S (DEA-S) were carried out in 36 hirsute women. 13 of these presented hormone levels as found in polycystic ovary syndrome (PCOS), 6 women presented a slight 21-hydroxylase deficiency (increased plasma 17-OH-P and decreased C after ACTH test with significant, p less than 0.01, increase of 17-OH-P/C and 17 women presented idiopathic hirsutism (IH). The hormonal pattern, in the basal condition, is not different in IH or in slight 21-hydroxylase deficiency. The ACTH test is able to differentiate between IH and adrenal hirsutism. PMID:2555033

Lucisano, A; Satta, M A; Tripodi, R; Mobili, L; De Cicco, F; Monaco, F; Dell'Acqua, S; Roche, J

1989-01-01

116

E2 Strength in the Radiative Charmed Baryon Decay  

E-print Network

The radiative decay $\\Sigma_Q^* \\rightarrow \\Lambda_Q\\gamma$ can have both magnetic dipole (M1) and electric quadrupole (E2) components. In the heavy quark limit $M_Q\\rightarrow\\infty$ the transition arises from the spin of the light degrees of freedom changing from $s_l=1$ to $s_l=0$ and hence the E2 contribution vanishes. We compute the leading contribution to the E2 strength in chiral perturbation theory and find that the amplitude is enhanced by a small energy denominator in the chiral limit. This enhancement essentially compensates for the $1/M_c$ suppression that is present in the charm system. We find a mixing ratio of order a few percent dependent upon the $\\Sigma_c^*--\\Sigma_c$ spin symmetry breaking mass difference. The analogous quantity in the b-baryon sector is smaller by a factor of $\\sim M_c/M_b$.

Martin J. Savage

1994-08-15

117

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

E-print Network

Imperial College London ­ EEE 1L1 Autumn 2009 E2.2 Analogue Electronics E2.2 Analogue Electronics Autumn 2009 E2.2 Analogue Electronics What analogue electronics is · Engineering, i.e. the analysis ­ EEE 3L1 Autumn 2009 E2.2 Analogue Electronics analogue electronics is not only · CMOS integrated

Papavassiliou, Christos

118

Investigation of (E, 2E) collisions and related phenomena  

Microsoft Academic Search

In this thesis I investigate (e, 2 e) processes, or electron impact ionization, using several theoretical methods. I first examine the problem using the Born approximations, particularly the Distorted Wave Born Approximation (DWBA), focusing on the underlying processes that dominate for ionization of the 2p state of Argon and Magnesium. I investigate as well the ionization of helium and hydrogen

Jason Manuel Martinez

2008-01-01

119

Low-energy behavior of $E2$ strength functions  

E-print Network

Electric quadrupole strength functions have been deduced from averages of a large number of $E2$ transition strengths calculated within the shell model for the nuclides $^{94}$Mo and $^{95}$Mo. These strength functions are at variance with phenomenological approximations as provided by the Reference Input Parameter Library RIPL-3 for calculations of reaction rates on the basis of the statistical model.

R. Schwengner

2014-11-04

120

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

121

E2 and C2 amplitudes for electroproduction of $?$  

E-print Network

We compute the amplitudes for the electromagnetic $\\gamma_v N \\to \\Delta$ transition in the framework of soliton models with quarks and mesons. The ratios E2/M1 and C2/M1 as functions of the photon four-momentum squared are dominated by the contribution of the pion cloud and are in reasonable agreement with the available experimental data.

M. Fiolhais; B. Golli; S. Sirca

1995-12-21

122

Cyclin E2 is required for embryogenesis in Xenopus laevis  

Microsoft Academic Search

In mammalian cells, E-type cyclins (E1 and E2) are generally believed to be required for entry into S phase. However, in mice, cyclin E is largely dispensable for normal embryogenesis. Moreover, Drosophila cyclin E plays a critical role in cell fate determination in neural lineages independently of proliferation. Thus, the functions of cyclin E, particularly during early development, remain elusive.

Tetsuya Gotoh; Noriko Shigemoto; Takeo Kishimoto

2007-01-01

123

Low-energy behavior of $E2$ strength functions  

E-print Network

Electric quadrupole strength functions have been deduced from averages of a large number of $E2$ transition strengths calculated within the shell model for the nuclides $^{94}$Mo and $^{95}$Mo. These strength functions are at variance with phenomenological approximations as provided by the Reference Input Parameter Library RIPL-3 for calculations of reaction rates on the basis of the statistical model.

Schwengner, R

2014-01-01

124

PROJECT ATHENA TECHNICAL PLAN Section E.2.1  

E-print Network

PROJECT ATHENA TECHNICAL PLAN Section E.2.1 Kerberos Authentication and Authorization System by S, named Kerberos, for the Athena environment. An appendix specifies the detailed design and protocols. Kerberos Aside from the 3-headed dog guarding Hades, the name given to the Athena authentication service

Saltzer, Jerome H.

125

Native E2F\\/RBF Complexes Contain Myb-Interacting Proteins and Repress Transcription of Developmentally Controlled E2F Target Genes  

Microsoft Academic Search

The retinoblastoma tumor suppressor protein (pRb) regulates gene transcription by binding E2F transcription factors. pRb can recruit several repressor complexes to E2F bound promoters; however, native pRb repressor complexes have not been isolated. We have purified E2F\\/RBF repressor complexes from Drosophila embryo extracts and characterized their roles in E2F regulation. These complexes contain RBF, E2F, and Myb-interacting proteins that have

Michael Korenjak; Barbie Taylor-Harding; Ulrich K. Binné; John S. Satterlee; Olivier Stevaux; Rein Aasland; Helen White-Cooper; Nick Dyson; Alexander Brehm

2004-01-01

126

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 and E2. Based on crystal structures of component proteins and homology modeling, we constructed a nearly cytoplasmic domain of E2 (cdE2), which follows a path from the E2 TM helix to the CP where it enters and exits

Baker, Timothy S.

127

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

128

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

129

Astro-E2 Magnesium Diboride High Current Leads  

Microsoft Academic Search

The recent discovery of superconducting properties in MgB2 and rapid development of small diameter steel-clad wires has opened up the possibility of enhancing the design of the baseline Astro-E2 high current lead assembly. Replacing YBCO filaments with MgB2 wires and modifying the heat sink location can give much higher margins against quench from temperature oscillations of the 4 K heat

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

2004-01-01

130

E2 component in subcoulomb breakup of ^{8}B  

E-print Network

We calculate the angular distribution and total cross section of the ^{7}Be fragment emitted in the break up reaction of ^{8}B on ^{58}Ni and ^{208}Pb targets at the subCoulomb beam energy of 25.8 MeV, within the non-relativistic theory of Coulomb excitation with proper three-body kinematics. The relative contributions of the E1, E2 and M1 multipolarities to the cross sections are determined. The E2 component makes up about 65% and 40% of the ^{7}Be total cross section for the ^{58}Ni and ^{208}Pb targets respectively. We find that the extraction of the astrophysical S-factor, S_{17}(0), for the ^{7}Be(p,\\gamma)^8B reaction at solar energies from the measurements of the cross sections of the ^{7}Be fragment in the Coulomb dissociation of ^{8}B at sub-Coulomb energies is still not free from the uncertainties of the E2 component.

R. Shyam; I. J. Thompson

1996-11-27

131

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

132

E2F7 and E2F8 promote angiogenesis through transcriptional activation of VEGFA in cooperation with HIF1  

PubMed Central

The E2F family of transcription factors plays an important role in controlling cell-cycle progression. While this is their best-known function, we report here novel functions for the newest members of the E2F family, E2F7 and E2F8 (E2F7/8). We show that simultaneous deletion of E2F7/8 in zebrafish and mice leads to severe vascular defects during embryonic development. Using a panel of transgenic zebrafish with fluorescent-labelled blood vessels, we demonstrate that E2F7/8 are essential for proper formation of blood vessels. Despite their classification as transcriptional repressors, we provide evidence for a molecular mechanism through which E2F7/8 activate the transcription of the vascular endothelial growth factor A (VEGFA), a key factor in guiding angiogenesis. We show that E2F7/8 directly bind and stimulate the VEGFA promoter independent of canonical E2F binding elements. Instead, E2F7/8 form a transcriptional complex with the hypoxia inducible factor 1 (HIF1) to stimulate VEGFA promoter activity. These results uncover an unexpected link between E2F7/8 and the HIF1-VEGFA pathway providing a molecular mechanism by which E2F7/8 control angiogenesis. PMID:22903062

Weijts, Bart G M W; Bakker, Walbert J; Cornelissen, Peter W A; Liang, Kuo-Hsuan; Schaftenaar, Frank H; Westendorp, Bart; de Wolf, Charlotte A C M T; Paciejewska, Maya; Scheele, Colinda L G J; Kent, Lindsey; Leone, Gustavo; Schulte-Merker, Stefan; de Bruin, Alain

2012-01-01

133

E2F7 and E2F8 promote angiogenesis through transcriptional activation of VEGFA in cooperation with HIF1.  

PubMed

The E2F family of transcription factors plays an important role in controlling cell-cycle progression. While this is their best-known function, we report here novel functions for the newest members of the E2F family, E2F7 and E2F8 (E2F7/8). We show that simultaneous deletion of E2F7/8 in zebrafish and mice leads to severe vascular defects during embryonic development. Using a panel of transgenic zebrafish with fluorescent-labelled blood vessels, we demonstrate that E2F7/8 are essential for proper formation of blood vessels. Despite their classification as transcriptional repressors, we provide evidence for a molecular mechanism through which E2F7/8 activate the transcription of the vascular endothelial growth factor A (VEGFA), a key factor in guiding angiogenesis. We show that E2F7/8 directly bind and stimulate the VEGFA promoter independent of canonical E2F binding elements. Instead, E2F7/8 form a transcriptional complex with the hypoxia inducible factor 1 (HIF1) to stimulate VEGFA promoter activity. These results uncover an unexpected link between E2F7/8 and the HIF1-VEGFA pathway providing a molecular mechanism by which E2F7/8 control angiogenesis. PMID:22903062

Weijts, Bart G M W; Bakker, Walbert J; Cornelissen, Peter W A; Liang, Kuo-Hsuan; Schaftenaar, Frank H; Westendorp, Bart; de Wolf, Charlotte A C M T; Paciejewska, Maya; Scheele, Colinda L G J; Kent, Lindsey; Leone, Gustavo; Schulte-Merker, Stefan; de Bruin, Alain

2012-10-01

134

Reduced Probabilities of E2-Transitions in {sup 174}Yb  

SciTech Connect

This paper describes the ground (gr) and exited states of even-even deformed nuclei with a phenomenological model, which takes into account the mixing of gr states, 0{sub n}{sup +}({beta}{sub n})-, 2{sub n}{sup +}({gamma}{sub n})- and {Kappa}{sup {pi}} 1{sub n}{sup +}- rotational bands. The calculation has been done for the isotope Yb. The energy spectra are found to be consistent with the energies from experimental data. The reduced probabilities of the electric quadrupole E2-transitions from {beta}{sub n} and {gamma}{sub n} band states are calculated and agree quite well with the experimental values.

Okhunov, A. A. [Quantum Science Center Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Institute for Nuclear Physics, Academy Science of Uzbekistan, 100214 Tashkent (Uzbekistan); Kassim, Hasan Abu [Quantum Science Center Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30

135

E2 and M1 strengths in heavy deformed nuclei  

E-print Network

Energy levels of the four lowest bands in 160,162,164Dy and 168Er, B(E2) transition strengths between the levels, and the B(M1) strength distribution of the ground state, all calculated within the framework of pseudo-SU(3) model, are presented. Realistic single-particle energies and quadrupole-quadrupole and pairing interaction strengths fixed from systematics were used in the calculations. The strengths of four rotor-like terms, all small relative to the other terms in the interaction, were adjusted to give an overall best fit to the energy spectra. The procedure yielded consistent parameter sets for the four nuclei.

J. P. Draayer; G. Popa; J. G. Hirsch

2001-03-27

136

Astro-E2 Magnesium Diboride High Current Leads  

SciTech Connect

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

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

2004-06-23

137

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

138

The E2/M1 ratio in {Delta} photoproduction  

SciTech Connect

The properties of the transition from the nucleon to the {Delta}(1232) serve as a benchmark for models of nucleon structure. To first order, N {r_arrow} {Delta} photo-excitation is dominated by a simple M1 quark spin-flip transition. At higher order, small L = 2 components in the N and {Delta} wavefunctions allow this excitation to proceed via an electric quadrupole transition. Since Nucleon models differ greatly on the mechanisms used to generate these L = 2 components,, the ratio of E2/M1 transitions (EMR) provides a sensitive test for structure models. Here, new high-precision measurements of p({rvec {gamma}}, {pi}) and p({rvec {gamma}}, {gamma}) cross sections and beam asymmetries have been combined with other polarization ratios in a simultaneous analysis of both reactions. Compton scattering has provided two important new constraints on the photo-pion amplitude. The E2/M1 mixing ratio for the N {r_arrow} {Delta} transition extracted from this analysis is EMR = {minus}3.0% {+-} 0.3 (stat+sys) {+-} 0.2 (model).

Sandorfi, A.M. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.; Blanpied, G. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Physics; Blecher, M. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Physics Dept.] [and others; LEGS Collaboration

1997-08-01

139

The Role of the E2F Transcription Factor Family in UV-Induced Apoptosis  

PubMed Central

The E2F transcription factor family is traditionally associated with cell cycle control. However, recent data has shown that activating E2Fs (E2F1-3a) are potent activators of apoptosis. In contrast, the recently cloned inhibitory E2Fs (E2F7 and 8) appear to antagonize E2F-induced cell death. In this review we will discuss (i) the potential role of E2Fs in UV-induced cell death and (ii) the implications of this to the development of UV-induced cutaneous malignancies. PMID:22272113

Hazar-Rethinam, Mehlika; Endo-Munoz, Liliana; Gannon, Orla; Saunders, Nicholas

2011-01-01

140

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

141

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

PubMed

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

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

2014-09-28

142

Investigation of (E, 2E) collisions and related phenomena  

NASA Astrophysics Data System (ADS)

In this thesis I investigate (e, 2 e) processes, or electron impact ionization, using several theoretical methods. I first examine the problem using the Born approximations, particularly the Distorted Wave Born Approximation (DWBA), focusing on the underlying processes that dominate for ionization of the 2p state of Argon and Magnesium. I investigate as well the ionization of helium and hydrogen and use the simplicity of the approximation to probe the incident particle effects on the Helium cross section. In both cases the results are compared with experiment. I also produce cross section results for ions near threshold, a regime that is currently under experimental investigation. In the second part of this thesis, I develop an ab initio method for doing these calculations called the X2e method. This is described in full, including derivation of the important features of the method. Preliminary results are presented in comparison with established theory.

Martinez, Jason Manuel

143

E2 transition probabilities in {sup 114}Te: A conundrum  

SciTech Connect

Lifetimes in {sup 114}Te were determined using the recoil distance Doppler-shift technique with a plunger device coupled to five HP Ge detectors enhanced by one Euroball cluster detector. The experiment was carried out at the Cologne FN Tandem facility using the {sup 93}Nb({sup 24}Mg,p2n) reaction at 90 MeV. The differential decay curve method in coincidence mode was employed to derive lifetimes for seven excited states, whereas the lifetime of an isomeric state was obtained in singles mode. The resulting E2 transition probabilities are shown to be very anomalous in comparison with the vibrational energy spacings of the ground-state band.

Moeller, O.; Warr, N.; Jolie, J.; Dewald, A.; Fitzler, A.; Linnemann, A.; Zell, K.O.; Garrett, P.E.; Yates, S.W. [Institut fuer Kernphysik, Universtaet zu Koeln, Zuelpicher Strasse 77, D-50937 Cologne (Germany); Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

2005-06-01

144

Extending PT symmetry from Heisenberg algebra to E2 algebra  

E-print Network

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

Carl M. Bender; R. J. Kalveks

2010-09-16

145

Characteristic of e2v CMOS sensors for astronomical applications  

NASA Astrophysics Data System (ADS)

We report the testing result of e2v CIS 107 CMOS sensor for temperature from 300K to 170K. The CIS 107 sensor is a prototype device with 10 different variations of pixel designs. The sensor has 1500 × 2000, 7 ?m pixels with 4 outputs. Each variation covers 1500 × 200 pixels. These are 4T pixels with high resistivity epitaxial silicon and back thinned to 11?m. At room temperature, the several variants of pixels show peak QE higher than 90%, readout noise around 5e- and dark current around 50e-/s/pix. The full well is about 15000 e- due to the limitation of the transfer gate capacitor. The CIS 107 device was further characterized at different device temperatures from 170K to 300K. The readout noise decreases and the full well increases as the device is operated at lower temperature.

Wang, Shiang-Yu; Ling, Hung-Hsu; Hu, Yen-Shan; Geary, John C.; Amato, Stephen M.; Pratlong, Jerome; Pike, Andrew; Jordan, Paul; Lehner, Matthew J.

2014-07-01

146

E-2D Advanced Hawkeye: primary flight display  

NASA Astrophysics Data System (ADS)

This paper is a response to the challenge of providing a large area avionics display for the E-2D AHE aircraft. The resulting display design provides a pilot with high-resolution visual information content covering an image area of almost three square feet (Active Area of Samsung display = 33.792cm x 27.0336 cm = 13.304" x 10.643" = 141.596 square inches = 0.983 sq. ft x 3 = 2.95 sq. ft). The avionics display application, design and performance being described is the Primary Flight Display for the E-2D Advanced Hawkeye aircraft. This cockpit display has a screen diagonal size of 17 inches. Three displays, with minimum bezel width, just fit within the available instrument panel area. The significant design constraints of supporting an upgrade installation have been addressed. These constraints include a display image size that is larger than the mounting opening in the instrument panel. This, therefore, requires that the Electromagnetic Interference (EMI) window, LCD panel and backlight all fit within the limited available bezel depth. High brightness and a wide dimming range are supported with a dual mode Cold Cathode Fluorescent Tube (CCFT) and LED backlight. Packaging constraints dictated the use of multiple U shaped fluorescent lamps in a direct view backlight design for a maximum display brightness of 300 foot-Lamberts. The low intensity backlight levels are provided by remote LEDs coupled through a fiber optic mesh. This architecture generates luminous uniformity within a minimum backlight depth. Cross-cockpit viewing is supported with ultra-wide field-of-view performance including contrast and the color stability of an advanced LCD cell design supports. Display system design tradeoffs directed a priority to high optical efficiency for minimum power and weight.

Paolillo, Paul W.; Saxena, Ragini; Garruba, Jonathan; Tripathi, Sanjay; Blanchard, Randy

2006-05-01

147

Analysis of a model reaction system containing cysteine and (E)-2-methyl-2-butenal, (E)-2-hexenal, or mesityl oxide.  

PubMed

Cysteine conjugates, resulting from the addition of cysteine to alpha,beta-unsaturated carbonyl compounds, are important precursors of odorant sulfur compounds in food flavors. The aim of this work was to better understand this chemistry in the light of the unexpected double addition of cysteine to two unsaturated aldehydes. These reactions were studied as a function of pH. When (E)-2-methyl-2-butenal (tiglic aldehyde, 4) was treated with cysteine in water at pH 8, the major product formed was the new compound (4R)-2-(2-[[(2R)-2-amino-2-carboxyethyl]thio]methylpropyl)-1,3-thiazolidine-4-carboxylic acid (6). Under acidic conditions (pH 1), we also observed a double addition, but the second cysteine was linked by a vinylic sulfide bond to form the previously unreported major product, (2R,2'R,E)-S,S'-(2,3-dimethyl-1-propene-1,3-diyl)bis-cysteine (7). When (E)-2-hexenal (12) was treated with cysteine under acidic conditions, the major product was the novel (4R,2' 'R)-2-[2'-(2' '-amino-2' '-carboxyethylthio)pentyl]-1,3-thiazolidine-4-carboxylic acid (13), and the formation of an vinylic sulfide compound analogous to 7 was not observed. Reduction of the acidic crude reaction mixture with NaBH(4) afforded 13 and the cysteine derivative (R)-S-[1-(2-hydroxyethyl)butyl]cysteine (14) in 14% yield. Treating (E)-2-hexenal with cysteine at pH 8 followed by NaBH(4) reduction yielded the new product (3R)-7-propylhexahydro-1,4-thiazepine-3-carboxylic acid (15). Addition of cysteine to mesityl oxide (16), at pH 8, followed by reduction with NaBH(4) furnished (R)-S-(3-hydroxy-1,1-dimethylbutyl)cysteine (3) and the new compound (3R)-hexahydro-5,7,7-trimethyl-1,4-thiazepine-3-carboxylic acid (18). PMID:14611186

Starkenmann, Christian

2003-11-19

148

Treg suppressive activity involves estrogen-dependent expression of programmed death-1 (PD-1).  

PubMed

Estrogen [17-beta-estradiol (E2)] is a potent driver of the FoxP3+ regulatory T cell (Treg) compartment. Recently, Tregs were further characterized by intracellular expression of the negative co-stimulatory molecule, programmed death-1 (PD-1). To clarify the role of PD-1 versus FoxP3 in E2-enhanced Treg suppression, we evaluated both markers and functional suppression in wild-type, estrogen receptor knockout (ERKO) mice and PD-1 KO mice. We demonstrate that intracellular PD-1 expression is also E2 sensitive, since E2 treatment increased intracellular PD-1 levels in CD4+FoxP3+ cells, and PD-1 expression and Treg suppression were reduced in ERKO mice. Surprisingly, PD-1 KO mice retained normal levels of FoxP3 expression, but Tregs from these mice lacked functional suppression. However, E2 pre-treatment of PD-1 KO mice partially restored functional Treg suppression without enhancing FoxP3 expression. Thus, functional Treg suppression in immunized mice without E2 pre-treatment was more closely linked to PD-1 expression than to FoxP3 expression. However, although enhanced PD-1 expression was E2 dependent, functional suppression was still enhanced by E2 pre-treatment in the absence of PD-1. These data clearly demonstrate that E2 can affect multiple regulatory elements that influence Treg suppression, including both PD-1-dependent and PD-1-independent pathways. PMID:17267414

Polanczyk, Magdalena J; Hopke, Corwyn; Vandenbark, Arthur A; Offner, Halina

2007-03-01

149

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

150

Disruption of plE2 , the gene for the E2 subunit of the plastid pyruvate dehydrogenase complex, in Arabidopsis causes an early embryo lethal phenotype  

Microsoft Academic Search

The pyruvate dehydrogenase multi-enzyme complex is the main source of acetyl-CoA formation in the plastids of plants and is composed of multiple copies of four different subunits, E1a, E1ß, E2, and E3. A T-DNA insertion into the gene for the plastidic E2 (dihydrolipoyl acetyltransferase) subunit, plE2, of the complex in Arabidopsis destroys the expression of that gene. The resulting mutation

Ming Lin; Robert Behal; David J. Oliver

2003-01-01

151

Apoptosis associated with deregulated E2F activity is dependent on E2F1 and Atm\\/Nbs1\\/Chk2  

Microsoft Academic Search

The retinoblastoma protein (Rb)\\/E2F pathway links cellular proliferation control to apoptosis and is critical for normal development and cancer prevention. Here we define a transcription-mediated pathway in which deregulation of E2F1 by ectopic E2F expression or Rb inactivation by E7 of human papillomavirus type 16 signals apoptosis by inducing the expression of Chk2, a component of the DNA damage response.

Harry A. Rogoff; Mary T. Pickering; Fiona M. Frame; Michelle E. Debatis; Yolanda Sanchez; Stephen N. Jones; Timothy F. Kowalik

2004-01-01

152

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

153

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

154

Distinct mechanisms of E2F regulation by Drosophila RBF1 and RBF2  

PubMed Central

RBF1, a Drosophila pRB family homolog, is required for cell cycle arrest and the regulation of E2F-dependent transcription. Here, we describe the properties of RBF2, a second family member. RBF2 represses E2F transcription and is present at E2F-regulated promoters. Analysis of in vivo protein complexes reveals that RBF1 and RBF2 interact with different subsets of E2F proteins. dE2F1, a potent transcriptional activator, is regulated specifically by RBF1. In contrast, RBF2 binds exclusively to dE2F2, a form of E2F that functions as a transcriptional repressor. We find that RBF2-mediated repression requires dE2F2. More over, RBF2 and dE2F2 act synergistically to antagonize dE2F1-mediated activation, and they co-operate to block S phase progression in transgenic animals. The network of interactions between RBF1 or RBF2 and dE2F1 or dE2F2 reveals how the activities of these proteins are integrated. These results suggest that there is a remarkable degree of symmetry in the arrangement of E2F and RB family members in mammalian cells and in Drosophila. PMID:12234932

Stevaux, Olivier; Dimova, Dessislava; Frolov, Maxim V.; Taylor-Harding, Barbie; Morris, Erick; Dyson, Nicholas

2002-01-01

155

Deregulated E2f-2 Underlies Cell Cycle and Maturation Defects in Retinoblastoma Null Erythroblasts?  

PubMed Central

By assessing the contribution of deregulated E2F activity to erythroid defects in Rb null mice, we have identified E2f-2 as being upregulated in end-stage red cells, where we show it is the major pRb-associated E2f and the predominant E2f detected at key target gene promoters. Consistent with its expression pattern, E2f-2 loss restored terminal erythroid maturation to Rb null red cells, including the ability to undergo enucleation. Deletion of E2f-2 also extended the life span of Rb null mice despite persistent defects in placental development, indicating that deregulated E2f-2 activity in differentiating erythroblasts contributes to the premature lethality of Rb null mice. We show that the aberrant entry of Rb null erythroblasts into S phase at times in differentiation when wild-type erythroblasts are exiting the cell cycle is inhibited by E2f-2 deletion. E2f-2 loss induced cell cycle arrest in both wild-type and Rb null erythroblasts and was associated with increased DNA double-strand breaks. These results implicate deregulated E2f-2 in the cell cycle defects observed in Rb null erythroblasts and reveal a novel role for E2f-2 during terminal red blood cell differentiation. The identification of a tissue-restricted role for E2f-2 in erythropoiesis highlights the nonredundant nature of E2f transcription factor activities in cell growth and differentiation. PMID:17923680

Dirlam, Alexandra; Spike, Benjamin T.; Macleod, Kay F.

2007-01-01

156

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

157

E2F integrates cell cycle progression with DNA repair, replication, and G2\\/M checkpoints  

Microsoft Academic Search

The E2F transcription factor family is known to play a key role in the timely expression of genes required for cell cycle progression and proliferation, but only a few E2F target genes have been identified. We explored the possibility that E2F regulators play a broader role by identifying additional genes bound by E2F in living human cells. A protocol was

Bing Ren; Hieu Cam; Yasuhiko Takahashi; Thomas Volkert; Jolyon Terragni; Richard A. Young; Brian David Dynlacht

2002-01-01

158

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

159

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

E-print Network

HUMAN T CELL RESPONSES TO HPV 16 E2 GENERATED WITH MONOCYTE-DERIVED DENDRITIC CELLS Emma J cancer. The E2 protein is required early in viral infection and there- fore may serve as a useful immune) prepared from monocytes and pulsed with bacte- rially produced HPV 16 E2 C-terminus protein were used

Gaston, Kevin

160

Mammalian oocytes are targets for prostaglandin E2 (PGE2) action  

E-print Network

for prostaglandin E2 (PGE2) action. Reproductive Biology andE2 receptors increases late in the periovulatory interval. BiologyE2 and F2alpha receptors in human myometrium, amnion, and choriodecidua with advancing gestation and labor. Biology

Duffy, Diane M; McGinnis, Lynda K; VandeVoort, Catherine A; Christenson, Lane K

2010-01-01

161

E2GK-pro: An Evidential Evolving Multimodeling Approach for Systems Behavior Prediction  

E-print Network

E2GK-pro: An Evidential Evolving Multimodeling Approach for Systems Behavior Prediction Lisa Serir and the as- sessment of the global model. In particular, the algorithm called E2GK-pro relies on an online procedure based on the Evidential Evolving Gustafsson-Kessel (E2GK) algo- rithm that ensures an evolving

Paris-Sud XI, Université de

162

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

163

Jab1 is a specificity factorfor E2F1-induced apoptosis  

PubMed Central

The members of the E2F family of transcription factors are key regulators of genes involved in cell cycle progression, cell fate determination, DNA damage repair, and apoptosis. Many cell-based experiments suggest that E2F1 is a stronger inducer of apoptosis than the other E2Fs. Our previous work identified the E2F1 marked box and flanking region as critical for the specificity in E2F1 apoptosis induction. We have now used a yeast two-hybrid screen to identify proteins that bind the E2F1 marked box and flanking regions, with a potential role in E2F1 apoptosis induction. We identified Jab1 as an E2F1-specific binding protein and showed that Jab1 and E2F1 coexpression synergistically induce apoptosis, coincident with an induction of p53 protein accumulation. In contrast, Jab1 does not synergize with E2F1 to promote cell cycle entry. Cells depleted of Jab1 are deficient for both E2F1-induced apoptosis and induction of p53 accumulation. We suggest that Jab1 is an essential cofactor for the apoptotic function of E2F1. PMID:16481464

Hallstrom, Timothy C.; Nevins, Joseph R.

2006-01-01

164

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

165

E2E: An Optimized IPsec Architecture for Secure And Fast Offload  

E-print Network

E2E: An Optimized IPsec Architecture for Secure And Fast Offload Daniel Migault, Daniel Palomares to Multiple Interfaces and to the Transport mode of IPsec. The benefits of this E2E architecture are mostly, then E2E uses IPsec Transport mode instead of Tunnel mode, which removes networking and security overhead

Paris-Sud XI, Université de

166

ELL Inhibits E2F1 Transcriptional Activity by Enhancing E2F1 Deacetylation via Recruitment of Histone Deacetylase 1  

PubMed Central

ELL (eleven-nineteen lysine-rich leukemia protein) was first identified as a translocation partner of MLL in acute myeloid leukemia; however, the exact mechanism of its action has remained elusive. In this study, we identified ELL as a direct downstream target gene of E2F1. Coimmunoprecipitation assays showed that ELL interacted with E2F1 in vitro and in vivo, leading to inhibition of E2F1 transcriptional activity. In addition, ELL enhanced E2F1 deacetylation via recruitment of histone deacetylase 1 (HDAC1). Notably, the MLL-ELL fusion protein lost the inhibitory role of ELL in E2F1 transcriptional activity. Furthermore, DNA damage induced ELL in an E2F1-dependent manner and ELL protected cells against E2F1-dependent apoptosis. Our findings not only connect ELL to E2F1 function and uncover a novel role of ELL in response to DNA damage but also provide an insight into the mechanism for MLL-ELL-associated leukemogenesis. PMID:24344198

Zhang, Wei; Ji, Wei; Liu, Xing; Ouyang, Gang

2014-01-01

167

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

168

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

169

DNA Damage Signals through Differentially Modified E2F1 Molecules To Induce Apoptosis  

PubMed Central

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

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

2012-01-01

170

Functional analysis of E2-mediated repression of the HPV18 P105 promoter.  

PubMed

Transcription of the transforming genes E6 and E7 of the human papillomavirus type 18 (HPV18) can be repressed by the product of the E2 open reading frame. Mutations were introduced in the cis-responsive elements upstream from the E6 and E7 transcriptional promoter, P105. The effect of these mutations in the absence or presence of E2 was examined in the human cervical carcinoma cell line C33, transfected with expression plasmids. In the presence of HPV18 E2, repression was relieved only when both of the two E2 binding motifs, immediately proximal to the P105 TATA box, were mutated. Mutation of a third E2 binding site, 110 nucleotides upstream of the TATA box, led to a slight but consistent activation in the presence of the full-length E2. Therefore, three E2 binding sites appear to be involved in the negative regulation of the P105 promoter by HPV18 E2. In the presence of the BPV1 E2 protein, only the E2 binding site most proximal to the promoter TATA box was involved in the P105 repression. The comparative analysis of the in vitro and in vivo properties of the human and bovine E2 proteins on the HPV18 P105 promoter provides new insights into the mechanism of transcriptional repression, which appears to involve steric hindrance at the site of transcriptional initiation. PMID:1645591

Thierry, F; Howley, P M

1991-01-01

171

E2Fs regulate the expression of genes involved in differentiation, development, proliferation, and apoptosis  

PubMed Central

The retinoblastoma protein (pRB) and its two relatives, p107 and p130, regulate development and cell proliferation in part by inhibiting the activity of E2F-regulated promoters. We have used high-density oligonucleotide arrays to identify genes in which expression changed in response to activation of E2F1, E2F2, and E2F3. We show that the E2Fs control the expression of several genes that are involved in cell proliferation. We also show that the E2Fs regulate a number of genes involved in apoptosis, differentiation, and development. These results provide possible genetic explanations to the variety of phenotypes observed as a consequence of a deregulated pRB/E2F pathway. PMID:11159908

Müller, Heiko; Bracken, Adrian P.; Vernell, Richard; Moroni, M. Cristina; Christians, Fred; Grassilli, Emanuela; Prosperini, Elena; Vigo, Elena; Oliner, Jonathan D.; Helin, Kristian

2001-01-01

172

Genomic loss of the putative tumor suppressor gene E2A in human lymphoma  

PubMed Central

The transcription factor E2A is essential for lymphocyte development. In this study, we describe a recurrent E2A gene deletion in at least 70% of patients with Sézary syndrome (SS), a subtype of T cell lymphoma. Loss of E2A results in enhanced proliferation and cell cycle progression via derepression of the protooncogene MYC and the cell cycle regulator CDK6. Furthermore, by examining the gene expression profile of SS cells after restoration of E2A expression, we identify several E2A-regulated genes that interfere with oncogenic signaling pathways, including the Ras pathway. Several of these genes are down-regulated or lost in primary SS tumor cells. These data demonstrate a tumor suppressor function of E2A in human lymphoid cells and could help to develop new treatment strategies for human lymphomas with altered E2A activity. PMID:21788410

Steininger, Anne; Möbs, Markus; Ullmann, Reinhard; Köchert, Karl; Kreher, Stephan; Lamprecht, Björn; Anagnostopoulos, Ioannis; Hummel, Michael; Richter, Julia; Beyer, Marc; Janz, Martin; Klemke, Claus-Detlev; Stein, Harald; Dörken, Bernd; Sterry, Wolfram; Schrock, Evelin

2011-01-01

173

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

174

Light-Dependent Regulation of DEL1 Is Determined by the Antagonistic Action of E2Fb and E2Fc1[W][OA  

PubMed Central

Endoreduplication represents a variation on the cell cycle in which multiple rounds of DNA replication occur without subsequent chromosome separation and cytokinesis, thereby increasing the cellular DNA content. It is known that the DNA ploidy level of cells is controlled by external stimuli such as light; however, limited knowledge is available on how environmental signals regulate the endoreduplication cycle at the molecular level. Previously, we had demonstrated that the conversion from a mitotic cell cycle into an endoreduplication cycle is controlled by the atypical E2F transcription factor, DP-E2F-LIKE1 (DEL1), that represses the endocycle onset. Here, the Arabidopsis (Arabidopsis thaliana) DEL1 gene was identified as a transcriptional target of the classical E2Fb and E2Fc transcription factors that antagonistically control its transcript levels through competition for a single E2F cis-acting binding site. In accordance with the reported opposite effects of light on the protein levels of E2Fb and E2Fc, DEL1 transcription depended on the light regime. Strikingly, modified DEL1 expression levels uncoupled the link between light and endoreduplication in hypocotyls, implying that DEL1 acts as a regulatory connection between endocycle control and the photomorphogenic response. PMID:21908689

Berckmans, Barbara; Lammens, Tim; Van Den Daele, Hilde; Magyar, Zoltan; Bogre, Laszlo; De Veylder, Lieven

2011-01-01

175

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

176

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

PubMed Central

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

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

2012-01-01

177

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

178

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

179

Association of Bovine Papillomavirus E2 Protein with Nuclear Structures In Vivo  

PubMed Central

Papillomaviruses are small DNA viruses which have the capacity to establish a persistent infection in mammalian epithelial cells. The papillomavirus E2 protein is a central coordinator of viral gene expression, genome replication, and maintenance. We have investigated the distribution of bovine papillomavirus E2 protein in nuclei of proliferating cells and found that E2 is associated with cellular chromatin. This distribution does not change during the entire cell cycle. The N-terminal transactivation domain, but not the C-terminal DNA-binding domain, of the E2 protein is responsible for this association. The majority of the full-length E2 protein can only be detected in chromatin-enriched fractions but not as a free protein in the nucleus. Limited micrococcal nuclease digestion revealed that the E2 protein partitioned to different chromatin regions. A fraction of the E2 protein was located at nuclear sites that are resistant against nuclease attack, whereas the remaining E2 resided on compact chromatin accessible to micrococcal nuclease. These data suggest that there are two pools of E2 in the cell nucleus: one that localizes on transcriptionally inactive compact chromatin and the other, which compartmentalizes to transcriptionally active nuclear structures of the cell. Our data also suggest that E2 associates with chromatin through cellular protein(s), which in turn is released from chromatin at 0.4 M salt. PMID:16051845

Kurg, Reet; Sild, Kristiina; Ilves, Aigi; Sepp, Mari; Ustav, Mart

2005-01-01

180

Activity of the human cytochrome c1 promoter is modulated by E2F.  

PubMed Central

The human cytochrome c(1) promoter is strongly activated in transfected Drosophila SL2 cells expressing exogenous human E2F1. Transfection-deletion experiments, DNase I protection by E2F1 and gel mobility-shift experiments locate E2F1 activation sites to two regions on either side of the transcription start site. Deletion of either region prevents E2F1 activation in transfected SL2 cells, suggesting a co-operative interaction between them. E2F6, a member of the E2F family that lacks transactivation domains but contains specific suppressor domains, inhibits cytochrome c(1) promoter activity when co-transfected into HeLa cells, indicating that the E2F proteins modulate the cytochrome c(1) promoter in mammalian cells. However, E2F is not a general regulator of oxidative phosphorylation genes since three additional nuclear-encoded mitochondrial genes were unaffected by E2F1 or E2F6. PMID:10998368

Luciakova, K; Barath, P; Li, R; Zaid, A; Nelson, B D

2000-01-01

181

Skp2 suppresses apoptosis in Rb1 deficient tumors by limiting E2F1 activity  

PubMed Central

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

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

2014-01-01

182

E2F2 and CREB cooperatively regulate transcriptional activity of cell cycle genes  

PubMed Central

E2F2 is essential for the maintenance of T lymphocyte quiescence. To identify the full set of E2F2 target genes, and to gain further understanding of the role of E2F2 in transcriptional regulation, we have performed ChIP-chip analyses across the genome of lymph node–derived T lymphocytes. Here we show that during quiescence, E2F2 binds the promoters of a large number of genes involved in DNA metabolism and cell cycle regulation, concomitant with their transcriptional silencing. A comparison of ChIP-chip data with expression profiling data on resting E2f2?/? T lymphocytes identified a subset of 51 E2F2-specific target genes, most of which are upregulated on E2F2 loss. Luciferase reporter assays showed a retinoblastoma-independent role for E2F2 in the negative regulation of these target genes. Importantly, we show that the DNA binding activity of the transcription factor CREB contributes to E2F2-mediated repression of Mcm5 and Chk1 promoters. siRNA-mediated CREB knockdown, expression of a dominant negative KCREB mutant or disruption of CREB binding by mutating a CRE motif on Mcm5 promoter, relieved E2F2-mediated transcriptional repression. Taken together, our data uncover a new regulatory mechanism for E2F-mediated transcriptional control, whereby E2F2 and CREB cooperate in the transcriptional repression of a subset of E2F2 target genes. PMID:24038359

Laresgoiti, Usua; Apraiz, Aintzane; Olea, Miguel; Mitxelena, Jone; Osinalde, Nerea; Rodriguez, Jose A.; Fullaondo, Asier; Zubiaga, Ana M.

2013-01-01

183

B (E2,4?2)/B(E2,2?0) ratio in even-even nuclei: Apparent anomalous behavior of the chromium isotopes  

NASA Astrophysics Data System (ADS)

We consider the ratio RE4=B (E2,4?2)/B(E2,2?0) for the lowest 2+ and 4+ states in even-even nuclei. In the rotational and vibrational models and the shell-model calculations considered here, RE4 is greater than 1; however, empirically, using National Nuclear Data Center adopted half-lives and energies for Cr48 and Cr50, this ratio is less than 1.

Hertz-Kintish, Daniel; Zamick, Larry; Robinson, Shadow J. Q.

2014-09-01

184

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

185

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

2014-06-26

186

In Vitro Effects of Anandamide and Prostamide E2 on Normal and Transformed Nerve Cells  

Microsoft Academic Search

We studied the effects of endocannabinoid anandamide and its cyclooxygenase derivative prostamide E2 on cultured cerebellar\\u000a granular cells and C6 glioma cells from rats. Prostamide E2 prevented apoptosis in cerebellar neurons induced by potassium\\u000a deprivation of cultures, while anandamide had no neuroprotective properties. Prostamide E2 did not modulate the survival rate\\u000a of glioma cells, while anandamide produced a cytotoxic effect.

E. L. Andrianova; E. E. Genrikhs; M. Yu. Bobrov; A. A. Lizhin; N. M. Gretskaya; L. E. Frumkina; L. G. Khaspekov; V. V. Bezuglov

2011-01-01

187

SUMO modification of the ubiquitin-conjugating enzyme E2-25K  

Microsoft Academic Search

Post-translational modification with small ubiquitin-related modifier (SUMO) alters the function of many proteins, but the molecular mechanisms and consequences of this modification are still poorly defined. During a screen for novel SUMO1 targets, we identified the ubiquitin-conjugating enzyme E2-25K (Hip2). SUMO attachment severely impairs E2-25K ubiquitin thioester and unanchored ubiquitin chain formation in vitro. Crystal structures of E2-25K(1–155) and of

Puck Knipscheer; Edith Oberhofer; Willem J van Dijk; Roman Körner; Jesper Velgaard Olsen; Stefan Jentsch; Frauke Melchior; Andrea Pichler; Titia K Sixma

2005-01-01

188

Sequence Determinants of E2-E6AP Binding Affinity and Specificity  

Microsoft Academic Search

The conjugation of ubiquitin to substrates requires a series of enzymatic reactions consisting of an activating enzyme (E1), conjugating enzymes (E2) and ligases (E3). Tagging the appropriate substrate with ubiquitin is achieved by specific E2–E3 and E3–substrate interactions. E6AP, a member of the HECT family of E3s, has been previously shown to bind and function with the E2s UbcH7 and

Ziad M. Eletr; Brian Kuhlman

2007-01-01

189

Emerging roles of E2Fs in cancer: an exit from cell cycle control  

Microsoft Academic Search

Mutations of the retinoblastoma tumour suppressor gene (RB1) or components regulating the RB pathway have been identified in almost every human malignancy. The E2F transcription factors function in cell cycle control and are intimately regulated by RB. Studies of model organisms have revealed conserved functions for E2Fs during development, suggesting that the cancer-related proliferative roles of E2F family members represent

Hui-Zi Chen; Shih-Yin Tsai; Gustavo Leone

2009-01-01

190

The AD1 and AD2 Transactivation Domains of E2A Are Essential for the Antiapoptotic Activity of the Chimeric Oncoprotein E2A-HLF  

PubMed Central

The chimeric oncoprotein E2A-HLF, generated by the t(17;19) chromosomal translocation in pro-B-cell acute lymphoblastic leukemia, incorporates the transactivation domains of E2A and the basic leucine zipper (bZIP) DNA-binding and protein dimerization domain of HLF (hepatic leukemic factor). The ability of E2A-HLF to prolong the survival of interleukin-3 (IL-3)-dependent murine pro-B cells after IL-3 withdrawal suggests that it disrupts signaling pathways normally responsible for cell suicide, allowing the cells to accumulate as transformed lymphoblasts. To determine the structural motifs that contribute to this antiapoptotic effect, we constructed a panel of E2A-HLF mutants and programmed their expression in IL-3-dependent murine pro-B cells (FL5.12 line), using a zinc-inducible vector. Neither the E12 nor the E47 product of the E2A gene nor the wild-type HLF protein was able to protect the cells from apoptosis induced by IL-3 deprivation. Surprisingly, different combinations of disabling mutations within the HLF bZIP domain had little effect on the antiapoptotic property of the chimeric protein, so long as the amino-terminal portion of E2A remained intact. In the context of a bZIP domain defective in DNA binding, mutants retaining either of the two transactivation domains of E2A were able to extend cell survival after growth factor deprivation. Thus, the block of apoptosis imposed by E2A-HLF in pro-B lymphocytes depends critically on the transactivating regions of E2A. Since neither DNA binding nor protein dimerization through the bZIP domain of HLF is required for this effect, we propose mechanisms whereby protein-protein interactions with the amino-terminal region of E2A allow the chimera to act as a transcriptional cofactor to alter the expression of genes regulating the apoptotic machinery in pro-B cells. PMID:9742120

Inukai, Takeshi; Inaba, Toshiya; Ikushima, Satoshi; Look, A. Thomas

1998-01-01

191

Dynamical (e,2e) investigations of tetrahydrofuran and tetrahydrofurfuryl alcohol as DNA analogues  

E-print Network

Dynamical (e,2e) investigations of tetrahydrofuran and tetrahydrofurfuryl alcohol as DNA analogues-impact ionization of the highest occupied molecular orbital of tetrahydrofuran (THF) are reported. Experimental

Wang, Yayu

192

E2–BRCA1 RING interactions dictate synthesis of mono- or specific polyubiquitin chain linkages  

Microsoft Academic Search

An E3 ubiquitin ligase mediates the transfer of activated ubiquitin from an E2 ubiquitin-conjugating enzyme to its substrate lysine residues. Using a structure-based, yeast two-hybrid strategy, we discovered six previously unidentified interactions between the human heterodimeric RING E3 BRCA1-BARD1 and the human E2s UbcH6, Ube2e2, UbcM2, Ubc13, Ube2k and Ube2w. All six E2s bind directly to the BRCA1 RING motif

Devin E Christensen; Peter S Brzovic; Rachel E Klevit

2007-01-01

193

NF-E2 Overexpression Delays Erythroid Maturation and Increases Erythrocyte Production  

PubMed Central

Summary The transcription factor Nuclear Factor-Erythroid 2 (NF-E2) is overexpressed in the vast majority of patients with polycythaemia vera (PV). In murine models, NF-E2 overexpression increases proliferation and promotes cellular viability in the absence of erythropoietin (EPO). EPO-independent growth is a hallmark of PV. We therefore hypothesized that NF-E2 overexpression contributes to erythrocytosis, the pathognomonic feature of PV. Consequently, we investigated the effect of NF-E2 overexpression in healthy CD34+ cells. NF-E2 overexpression led to a delay in erythroid maturation, manifested by a belated appearance of glycophorin A-positive erythroid precursors. Maturation delay was similarly observed in primary PV patient erythroid cultures compared to healthy controls. Protracted maturation led to a significant increase in the accumulated number of erythroid cells both in PV cultures and in CD34+ cells overexpressing NF-E2. Similarly, NF-E2 overexpression altered erythroid colony formation, leading to an increase in BFU-E formation. These data indicate that NF-E2 overexpression delays the early phase of erythroid maturation, resulting in an expansion of erythroid progenitors, thereby increasing the number of erythrocytes derived from one CD34+ cell. These data propose a role for NF-E2 in mediating the erythrocytosis of PV. PMID:19466964

Mutschler, Manuel; Magin, Angela S.; Buerge, Martina; Roelz, Roland; Schanne, Daniel H.; Will, Britta; Pilz, Ingo H.; Migliaccio, Anna Rita; Pahl, Heike L.

2009-01-01

194

Functional impact of colorectal cancer-associated mutations in the transcription factor E2F4.  

PubMed

The transcription factor E2F4 plays a critical role in cell cycle progression of normal and cancerous intestinal epithelial cells. Contrary to other E2Fs, the coding region of the E2F4 gene contains a longer spacer segment of a CAG trinucleotide repeat sequence encoding 13 consecutive serine residues, which is highly vulnerable to frameshift mutations in situations of genetic instability. Mutations in this region of the E2F4 gene have been observed in colorectal tumors with microsatellite instability. However, the effect of these changes on its function in colorectal cancer cells is currently unknown. We generated E2F4(CAG)?? and E2F4(CAG)?? mutants and compared their activity to the E2F4 wild-type, E2F4(CAG)??. Luciferase assays with the thymidine kinase-luc reporter gene revealed that the mutants were more transcriptionally active than wild-type E2F4. The mechanism of increased activity of E2F4 was primarily related to protein stability, due to a significantly enhanced half-life of E2F4 mutants comparatively to that of wild-type E2F4. However, the association with the pocket protein p130/RBL2 did not account for this increased protein stability. Sequencing analysis of the endogenous E2F4 gene in a series of colorectal cancer cell lines showed that the microsatellite-unstable cell line SW48 exhibited a serine deletion in this gene. Accordingly, E2F4 half-life was much more elevated in SW48 cells in comparison to Caco-2/15, a microsatellite-stable cell line. Notably, in soft-agar assays, both mutants more potently increased anchorage-independent growth in comparison to wild-type E2F4. In conclusion, our data demonstrate that cancer-associated E2F4 mutations enhance the capacity of colorectal cancer cells to grow without anchorage, thereby contributing to tumor progression. PMID:24100580

Paquin, Marie-Christine; Leblanc, Caroline; Lemieux, Etienne; Bian, Benjamin; Rivard, Nathalie

2013-12-01

195

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

196

Advances in hormone replacement therapy: weight benefits of drospirenone, a 17alpha-spirolactone-derived progestogen.  

PubMed

Hormone replacement therapy (HRT) remains the most effective treatment for menopausal symptom relief, and may provide cardiovascular benefits in younger women initiating treatment soon after menopause. However, large surveys indicate that many symptomatic women refuse or discontinue HRT prematurely owing to fear of weight gain. A continuous combined HRT containing 17beta-estradiol (E(2)) 1 mg plus drospirenone (DRSP) 2 mg is effective in relieving menopausal symptoms and preventing postmenopausal osteoporosis. DRSP is a unique synthetic progestogen with a pharmacological profile similar to that of natural progesterone, including antialdosterone activity, a property not exhibited by other synthetic progestogens. DRSP can therefore reduce estrogen-related sodium and water retention in postmenopausal women receiving HRT via the renin-angiotensin-aldosterone system, which regulates sodium and water balance. This may translate into weight benefits. Pooled data from two placebo-controlled clinical trials (n = 333) indicated statistically significant weight loss of -1.5 kg at 6 and 12 months in postmenopausal women receiving E(2)/DRSP vs. placebo (p < 0.001). In a third randomized controlled trial (n = 1147), women receiving E(2)/DRSP maintained or lost weight, whereas weight increases were observed in women receiving E(2) monotherapy (p < 0.0125). E(2)/DRSP could help maintain or even slightly decrease body weight during treatment, potentially improving HRT acceptance and compliance. PMID:18075844

Foidart, Jean-Michel; Faustmann, Thomas

2007-12-01

197

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

198

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

PubMed Central

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

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

2010-01-01

199

Allosteric Activation of E2-RING Finger-Mediated Ubiquitylation by a Structurally Defined Specific E2-Binding Region of gp78  

SciTech Connect

The activity of RING finger ubiquitin ligases (E3) is dependent on their ability to facilitate transfer of ubiquitin from ubiquitin-conjugating enzymes (E2) to substrates. The G2BR domain within the E3 gp78 binds selectively and with high affinity to the E2 Ube2g2. Through structural and functional analyses, we determine that this occurs on a region of Ube2g2 distinct from binding sites for ubiquitin-activating enzyme (E1) and RING fingers. Binding to the G2BR results in conformational changes in Ube2g2 that affect ubiquitin loading. The Ube2g2:G2BR interaction also causes an 50-fold increase in affinity between the E2 and RING finger. This results in markedly increased ubiquitylation by Ube2g2 and the gp78 RING finger. The significance of this G2BR effect is underscored by enhanced ubiquitylation observed when Ube2g2 is paired with other RING finger E3s. These findings uncover a mechanism whereby allosteric effects on an E2 enhance E2-RING finger interactions and, consequently, ubiquitylation.

Das, Ranabir; Mariano, Jennifer; Tsai, Yien Che; Kalathur, Ravi C.; Kostova, Zlatka; Li, Jess; Tarasov, Sergey G.; McFeeters, Robert L.; Altieri, Amanda S.; Ji, Xinhua; Byrd, R. Andrew; Weissman, Allan M.; (NCI)

2010-11-12

200

Destructive interference of E2 matrix elements in a triaxial rotor model  

SciTech Connect

A triaxial rotor model with independent inertia and electric quadrupole tensors is applied to nuclei that have certain E2 matrix elements equal to zero. It is shown that such vanishing E2 matrix elements are explained by the model as a destructive interference effect. The example of 196Pt is considered.

Allmond, James M [ORNL; Wood, J. L. [Georgia Institute of Technology; Kulp, W. D. [Georgia Institute of Technology

2010-01-01

201

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

202

Transcriptional and Nontranscriptional Functions of E2F1 in Response to DNA Damage  

PubMed Central

E2F is a family of transcription factors that regulate the expression of genes involved in a wide range of cellular processes, including cell-cycle progression, DNA replication, DNA repair, differentiation, and apoptosis. E2F1, the founding member of the family, undergoes posttranslational modifications in response to DNA damage, resulting in E2F1 stabilization. In some cases, E2F1 is important for DNA damage-induced apoptosis through the transcriptional activation of p73 and perhaps other proapoptotic target genes. However, in other contexts, E2F1 can stimulate DNA repair and promote survival in response to DNA damage. The E2F1 protein accumulates at sites of both DNA double-strand breaks and UV radiation-induced damage, indicating that E2F1 has a nontranscriptional function at sites of damage. This review summarizes recent progress made in understanding the role of E2F1 in the DNA damage response, including transcription-independent activities that facilitate DNA repair in the context of chromatin. PMID:22180494

Biswas, Anup K.; Johnson, David G.

2013-01-01

203

Environment to Environment (E2E) Communication Systems for Collaborative Work  

E-print Network

, USA ABSTRACT E2E is an initiative to harness the power of the World Wide Web (WWW) along with the development and popularity of the World Wide Web. Internet based communication approaches have begun to make, there is no emphasis on harnessing the power of the World Wide Web in these solutions. Environment to Environment (E2E

Reif, Rafael

204

E2 Interference Effects in the C(?,?0)16O12 Reaction  

NASA Astrophysics Data System (ADS)

The E1-E2 interference sign between the Ec.m.=2.68-MeV E2 resonance and an underlying E1 strength has been measured for the first time. An E1-E2 asymmetry parameter of a=0.07±0.05 was extracted from the thick-target ?-ray yields of the narrow resonance at angles of 45° and 135°. The positive sign of a corresponded to constructive interference at forward angles and, further, allowed the interference between the resonance and an E2 background to be identified as constructive below the resonance energy. The E2-E2 interference was then used to evaluate the global SE2 data within the vicinity of the resonance 2.5?Ec.m.?3.0MeV. An analysis of the global SE2 data that agreed with the interference scenario has determined the E2-E2 interference scheme of the 4.34-MeV resonance and background, resulting in a value of SE2(300)=62-6+9keVb.

Sayre, D. B.; Brune, C. R.; Carter, D. E.; Jacobs, D. K.; Massey, T. N.; O'Donnell, J. E.

2012-10-01

205

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

206

Activation of BPV1 replication in vitro by the transcription factor E2  

Microsoft Academic Search

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

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

1991-01-01

207

Production and characterization of mouse monoclonal antibodies reactive to Chikungunya envelope E2 glycoprotein  

Microsoft Academic Search

Chikungunya fever is an arbovirosis of major impact in public health in Asia and Africa. Chikungunya (CHIK) virus is member of the genus Alphavirus and belongs to the Semliki Forest (SF) antigenic complex. We describe for the first time a panel of monoclonal antibodies (MAbs) reactive to CHIK envelope E2 glycoprotein. For the screening of E2-specific MAbs, we expressed a

Anne-Claire Bréhin; Laetitia Rubrecht; Martha Erika Navarro-Sanchez; Valérie Maréchal; Marie-Pascale Frenkiel; Priscilla Lapalud; Daniel Laune; Amadou Alpha Sall; Philippe Desprès

2008-01-01

208

E2F Inhibition Synergizes with Paclitaxel in Lung Cancer Cell Lines  

PubMed Central

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

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

2014-01-01

209

Preinduction cervical ripening: A comparison of intracervical prostaglandin E 2 gel versus the Foley catheter  

Microsoft Academic Search

OBJECTIVE: Both prostaglandin E2 gel and an intracervical balloon catheter have been shown to be effective for cervical ripening. The purpose of this study is to compare the efficacy of intracervical prostaglandin E2 gel with an intracervical Foley catheter for preinduction cervical ripening.STUDY DESIGN: A randomized, prospective study was conducted in the Maternity Care Center at the Foothills Hospital at

Rick D. St. Onge; Gregory T. Connors

1995-01-01

210

Cervical ripening before medical induction of labor: a comparison of prostaglandin E 2, estradiol, and oxytocin  

Microsoft Academic Search

Objective: Our purpose was to evaluate the effectiveness of oxytocin, prostaglandin, E2 intracervical gel, and estradiol cream for ripening the very unfavorable cervix in patients requiring induction of labor at term.Study design: This prospective, randomized study was conducted in a population of women with a very unfavorable cervix (Bishop score <4) requiring induction of labor. The patients received prostaglandin E2

Everett F. Magann; Kenneth G. Perry; James R. Dockery; J. David Bass; Suneet P. Chauhan; John C. Morrison

1995-01-01

211

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

212

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

Microsoft Academic Search

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

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

2008-01-01

213

The CDK4-pRB-E2F1 pathway controls insulin secretion  

PubMed Central

CDK4-pRB-E2F1 cell cycle regulators are robustly expressed in non-proliferating ?-cells, suggesting that besides the control of ?-cell number the CDK4-pRB-E2F1 pathway has a role in ?-cell function. We show here that E2F1 directly regulates the expression of Kir6.2, which is a key component of the KATP channel involved in the regulation of glucose-induced insulin secretion. We demonstrate, by in tissue chromatin immunoprecipitation analysis that Kir6.2 expression is regulated at the promoter level by the CDK4-pRB-E2F1 pathway. Consistently, inhibition of CDK4, or genetic inactivation of E2F1 results in decreased expression of Kir6.2, impaired insulin secretion, and glucose intolerance in mice. Furthermore we show that rescue of Kir6.2 expression restores insulin secretion in E2f1 ?/? ?-cells. Finally, we demonstrate that CDK4 is activated by glucose through the insulin pathway, ultimately resulting in E2F1 activation and consequently in Kir6.2 increased expression. In summary we provide evidence that the CDK4-pRB-E2F1 regulatory pathway is involved in glucose homeostasis, defining a new link between cell proliferation and metabolism. PMID:19597485

Annicotte, Jean-Sebastien; Blanchet, Emilie; Chavey, Carine; Iankova, Irena; Costes, Safia; Assou, Said; Teyssier, Jacques; Dalle, Stephane; Sardet, Claude; Fajas, Lluis

2009-01-01

214

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

PubMed Central

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 G1/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, Jose

2013-01-01

215

Structure of a Pestivirus Envelope Glycoprotein E2 Clarifies Its Role in Cell Entry  

PubMed Central

Summary Enveloped viruses have developed various adroit mechanisms to invade their host cells. This process requires one or more viral envelope glycoprotein to achieve cell attachment and membrane fusion. Members of the Flaviviridae such as flaviviruses possess only one envelope glycoprotein, E, whereas pestiviruses and hepacivirus encode two glycoproteins, E1 and E2. Although E2 is involved in cell attachment, it has been unclear which protein is responsible for membrane fusion. We report the crystal structures of the homodimeric glycoprotein E2 from the pestivirus bovine viral diarrhea virus 1 (BVDV1) at both neutral and low pH. Unexpectedly, BVDV1 E2 does not have a class II fusion protein fold, and at low pH the N-terminal domain is disordered, similarly to the intermediate postfusion state of E2 from sindbis virus, an alphavirus. Our results suggest that the pestivirus and possibly the hepacivirus fusion machinery are unlike any previously observed. PMID:23273918

El Omari, Kamel; Iourin, Oleg; Harlos, Karl; Grimes, Jonathan M.; Stuart, David I.

2013-01-01

216

Isolation of cDNA encoding the human NF-E2 protein  

SciTech Connect

The human homolog of mouse NF-E2 was isolated from the K562 cell line and found to encode a member of the basic leucine-zipper family of DNA-binding regulatory proteins. The deduced amino acid sequence of the mouse and human proteins exhibited near identity. Comparison to the related protein, Nrfl, revealed significant homologies at isolated regions, particularly within the basic domain, suggesting that NF-E2 and Nrfl are members of a distinct subfamily of basic leucine-zipper proteins that share similar DNA-binding properties. High levels of human NF-E2 mRNA were observed in human erythroleukemic cell lines examined. Extensive survey of human tissue samples found NF-E2 expression not limited to erythropoeitic organs. Expression in the colon and testis suggests that NF-E2 may participate in the regulation of genes other than globin.

Chan, J.Y.; Han, Xiao-Liang; Kan, Yuet Wai (Univ. of California, San Francisco, CA (United States))

1993-11-15

217

Biochem. J. (2009) 418, 683690 (Printed in Great Britain) doi:10.1042/BJ20081943 683 Effect of Arabidopsis COP10 ubiquitin E2 enhancement activity across E2  

E-print Network

of Arabidopsis COP10 ubiquitin E2 enhancement activity across E2 families and functional conservation among its photomorphogenic 10) is a UEV [Ub (ubiquitin)-conjugating enzyme (E2) variant protein] that is required the activity of Ub-conjugating enzyme (E2) in vitro. To investigate whether COP10 might act as a general

Deng, Xing-Wang

218

A Transactivator Function of Cottontail Rabbit Papillomavirus E2 Is Essential for Tumor Induction in Rabbits  

PubMed Central

Infection of domestic rabbits with cottontail rabbit papillomavirus (CRPV) causes local papillomas which progress to carcinomas in more than 80% of cases. This animal model system therefore allows the identification of molecular mechanisms required for the induction and progression of epithelial tumors. The viral E2 protein stimulates both viral DNA replication and transcription, and these functions can be genetically separated. We introduced the respective mutations into CRPV E2 and found, in line with published data for other papillomavirus E2 proteins, that mutation of the highly conserved amino acid 37 or 73 resulted in replication-competent but transactivation-deficient E2 proteins, whereas E2 proteins with mutations at residue 39 were replication deficient and transactivation competent. The R37A, I73L, and I73A E2 mutants, showing a loss of transactivation function, and the R37K E2 mutant, which is still transactivation competent, were introduced into the whole genome of CRPV, which was then injected into the skin of rabbits. Strikingly, the ability to induce tumors within 6 weeks was abolished by each of the E2 mutations, in contrast to the tumor induction rate (93%) obtained with wild-type CRPV DNA. Two small papillomas induced by mutant E2 I73A CRPV DNA appeared as late as 12 or 24 weeks postinjection, were significantly smaller, and showed no further extension of growth. These data suggest that functionally conserved amino acids in the transactivation domain of E2 are also required for the induction and growth of epithelial tumors in rabbits infected with CRPV. PMID:12388680

Jeckel, Sonja; Huber, Evamaria; Stubenrauch, Frank; Iftner, Thomas

2002-01-01

219

Estradiol-17?, prostaglandin E2 (PGE2) and the prostaglandin E2 receptor are involved in PGE2 positive feedback loop in the porcine endometrium  

PubMed Central

Before implantation, the porcine endometrium and trophoblast synthesize elevated amounts of luteoprotective prostaglandin E2 (PGE2). We hypothesized that embryo signal, estradiol-17? (E2) and PGE2 modulate expression of key enzymes in PG synthesis: prostaglandin-endoperoxide synthase-2 (PTGS2), PGE synthase (mPGES-1), PGF synthase (PGFS), and prostaglandin 9-ketoreductase (CBR1); as well as PGE2 receptor (PTGER2 and 4) expression and signaling within the endometrium. We determinated the site of action of PGE2 in endometrium during the estrous cycle and pregnancy. Endometrial tissue explants obtained from gilts (n=6) on days 11-12 of the estrous cycle were treated with vehicle (control), PGE2 (100 nM), E2 (1-100 nM) or phorbol 12-myristate 13-acetate (100 nM, positive control). E2 increased PGE2 secretion through elevating expression of mPGES-1 mRNA and PTGS2 and mPGES-1 protein in endometrial explants. By contrast, E2 decreased PGFS and CBR1 protein expression. E2 also stimulated PTGER2 but not PTGER4 protein content. PGE2 enhanced mPGES-1 and PTGER2 mRNA as well as PTGS2, mPGES-1 and PTGER2 protein expression. PGE2 had no effect on PGFS, CBR1 and PTGER4 expression and PGF2? release. Treatment of endometrial tissue with PGE2 increased cAMP production. Co-treatment with PTGER2 antagonist (AH6809) but not PTGER4 antagonist (GW 627368X) inhibited significantly PGE2-mediated cAMP production. PTGER2 protein was localized in luminal and glandular epithelium and blood vessels of endometrium, and was significantly up-regulated on days 11-12 of pregnancy. Our results suggest that E2, prevents luteolysis through enzymatic modification of PG synthesis and that E2, PGE2 and endometrial PTGER2 are involved in PGE2 positive feedback loop in porcine endometrium. PMID:19359378

Waclawik, Agnieszka; Jabbour, Henry N.; Blitek, Agnieszka; Ziecik, Adam J.

2009-01-01

220

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

221

Differential actions of estrogen and SERMs in regulation of the actin cytoskeleton of endometrial cells.  

PubMed

Estrogen and selective estrogen receptor modulators (SERMs) differentially impact endometrial cell function, however, the biological basis of these differences is not established. Deregulated cell adhesion to the extracellular matrix, cell movement and invasion are related to endometrial disorders, such as endometriosis or endometrial cancer. Remodeling of the actin cytoskeleton is required to achieve cell adhesion and movement. Estrogen receptor (ER) regulates actin and cell membrane remodeling through extra-nuclear signaling cascades. In this article, we show that administration of 17beta-estradiol (E2) and tamoxifen (TAM) to immortalized Ishikawa endometrial cells or to human endometrial stromal cells (ESC) results in remodeling of actin fibers and cell membrane. This is linked to rapid phosphorylation on Thr(558) of the actin-binding protein moesin and enhanced migration and invasion of normal and Ishikawa cells. Raloxifene (RAL) does not result in moesin activation or actin remodeling. When endometrial cells are exposed to E2 in the presence of TAM or RAL, both SERMs interfere with the recruitment of moesin, with the remodeling of the cytoskeleton, and with cell movement and migration induced by E2. The differential actions of E2, TAM and RAL are linked to a distinct modulation of the extra-nuclear signaling of ER to G proteins and to the Rho-associated kinase. These findings increase our understanding of the actions of estrogen and SERMs in endometrial cells and highlight potential molecular targets to interfere with the estrogen-related altered cell adhesion encountered in endometrial disorders. PMID:19541800

Flamini, M I; Sanchez, A M; Goglia, L; Tosi, V; Genazzani, A R; Simoncini, T

2009-10-01

222

The use of primary hepatocytes from brown trout (Salmo trutta lacustris) and the fish cell lines RTH-149 and ZF-L for in vitro screening of (anti)estrogenic activity of wood extractives.  

PubMed

Wood extractives are constituents of wood present in pulp and paper mill effluents, which may cause reproductive disturbances in fish. In the present study, we examined three cellular in vitro bioassays in order to assess (anti)estrogenic potencies of the wood extractives dehydroabietic acid (DHAA), isopimaric acid (IPA), betulinol (BET), hydroxymatairesinol (HMR), a phytosterol preparation (ULT), an oxidized phytosterol preparation (OX) and the model estrogen 17beta-estradiol (E2). The test systems used were primary hepatocyte cultures from brown trout and two piscine liver cell lines, RTH-149 and ZF-L. Estrogenicity was measured as vitellogenin (Vtg) secretion in cell culture medium. The primary hepatocytes cultures responded to E2 in a dose-dependent way. Vtg induction was inhibited with a simultaneous exposure to 4-hydroxytamoxifen (4-HT) indicating an estrogen receptor mediated response. DHAA and ULT induced a weak statistically non-significant Vtg production, and weak additive effects were found in some combination treatments of wood extractives and E2. Additionally, a pulp mill effluent tested on primary hepatocytes induced Vtg production when exposed at a 1% dilution. The cell lines secreted negligible amounts of Vtg upon E2 stimulation, which was neither dose-dependent nor inhibited by 4-HT. In conclusion, trout primary hepatocytes could be useful for assessing (anti)estrogenic potencies of compounds, and the wood extractives and a pulp mill effluent showed only weak or no estrogenic activity in this model system. PMID:18206344

Christianson-Heiska, I; Isomaa, B

2008-04-01

223

Oral feeding with ethinyl estradiol suppresses and treats experimental autoimmune encephalomyelitis in SJL mice and inhibits the recruitment of inflammatory cells into the central nervous system.  

PubMed

There is much interest in the possible ameliorating effects of estrogen on various autoimmune diseases. We previously established the protective effects of 17 beta-estradiol (E2) on experimental autoimmune encephalomyelitis (EAE). In the current study we investigated the effectiveness of oral treatment with ethinyl estradiol (EE) on EAE and the mechanisms involved. Ethinyl estradiol is a semisynthetic estrogen compound found in birth control pills, and its chemical structure allows this compound to retain activity when given orally. We found that oral EE, like E2, drastically suppressed EAE induced by proteolipid protein 139-151 peptide when given at initiation of EAE. However, unlike E2, EE reduced clinical severity when given after the onset of clinical signs. Treatment with EE significantly decreased the secretion of proinflammatory cytokines (IFN-gamma, TNF-alpha, and IL-6) by activated T cells as well as the expression of a key matrix metalloproteinase, disease-mediating chemokines/receptors, and IgG2a levels, but increased the expression of TGF-beta 3 in the CNS. The absence of infiltrating lymphocytes together with the suppression of cytokines, matrix metalloproteinase, and chemokines/receptors suggests that EE, like E2, protects mice from EAE by inhibiting the recruitment of T cells and macrophages into the CNS. These results suggest that oral ethinyl estradiol might be a successful candidate as therapy for multiple sclerosis. PMID:12538720

Subramanian, Sandhya; Matejuk, Agata; Zamora, Alex; Vandenbark, Arthur A; Offner, Halina

2003-02-01

224

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

225

Catalytic diesel particulate filters reduce the in vitro estrogenic activity of diesel exhaust.  

PubMed

An in vitro reporter gene assay based on human breast cancer T47D cells (ER-CALUX) was applied to examine the ability of diesel exhaust to induce or inhibit estrogen receptor (ER)-mediated gene expression. Exhaust from a heavy-duty diesel engine was either treated by iron- or copper/iron-catalyzed diesel particulate filters (DPFs) or studied as unfiltered exhaust. Collected samples included particle-bound and semivolatile constituents of diesel exhaust. Our findings show that all of the samples contained compounds that were able to induce ER-mediated gene expression as well as compounds that suppressed the activity of the endogenous hormone 17beta-estradiol (E2). Estrogenic activity prevailed over antiestrogenic activity. We found an overall ER-mediated activity of 1.63 +/- 0.31 ng E2 CALUX equivalents (E2-CEQs) per m(3) of unfiltered exhaust. In filtered exhaust, we measured 0.74 +/- 0.07 (iron-catalyzed DPF) and 0.55 +/- 0.09 ng E2-CEQ m(-3) (copper/iron-catalyzed DPF), corresponding to reductions in estrogenic activity of 55 and 66%, respectively. Our study demonstrates that both catalytic DPFs lowered the ER-mediated endocrine-disrupting potential of diesel exhaust. PMID:18264702

Wenger, Daniela; Gerecke, Andreas C; Heeb, Norbert V; Naegeli, Hanspeter; Zenobi, Renato

2008-04-01

226

Direct visualization of Agrobacterium-delivered VirE2 in recipient cells.  

PubMed

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

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

2014-02-01

227

Comparison of the Structure and DNA-binding Properties of the E2 Proteins from an Oncogenic and  

E-print Network

Comparison of the Structure and DNA-binding Properties of the E2 Proteins from an Oncogenic-risk HPV types, the papillomavirus E2 protein binds to four sites within the viral long con- trol region-binding domain (DBD) from the HPV 6 E2 protein. We show that the HPV 6 E2 DBD is structurally more similar

Gaston, Kevin

228

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

229

Phosphorylation Regulates Binding of the Human Papillomavirus Type 8 E2 Protein to Host Chromosomes  

PubMed Central

The papillomavirus E2 proteins are indispensable for the viral life cycle, and their functions are subject to tight regulation. The E2 proteins undergo posttranslational modifications that regulate their properties and roles in viral transcription, replication, and genome maintenance. During persistent infection, the E2 proteins from many papillomaviruses act as molecular bridges that tether the viral genomes to host chromosomes to retain them within the host nucleus and to partition them to daughter cells. The betapapillomavirus E2 proteins bind to pericentromeric regions of host mitotic chromosomes, including the ribosomal DNA loci. We recently reported that two residues (arginine 250 and serine 253) within the chromosome binding region of the human papillomavirus type 8 (HPV8) E2 protein are required for this binding. In this study, we show that serine 253 is phosphorylated, most likely by protein kinase A, and this modulates the interaction of the E2 protein with cellular chromatin. Furthermore, we show that this phosphorylation occurs in S phase, increases the half-life of the E2 protein, and promotes chromatin binding from S phase through mitosis. PMID:22787207

Sekhar, Vandana

2012-01-01

230

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

231

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

232

Cell cycle molecules and vertebrate neuron death: E2F at the hub.  

PubMed

Vertebrate neuron cell death is both a normal developmental process and the catastrophic outcome of nervous system trauma or degenerative disorders. Although the mechanisms of such death include an evolutionarily conserved core apoptotic pathway that is highly homologous to that first described by Horvitz and co-workers in Caenorhabditis elegans, it appears that many instances of neuron death additionally require the transcription-dependent induction of proapoptotic molecules. One such proapoptotic transcriptional pathway revealed by studies over the past decade revolves about the transcription factor E2F and those molecules that either regulate E2F activity or that are direct or indirect transcriptional targets of E2F. Many of the molecules associated with the E2F apoptotic pathway in postmitotic neurons also participate in the cell cycle in proliferating cells. Observations in human material and in animal and cell culture models show widespread correlation between changes in expression, activity and subcellular localization of E2F-related cell cycle molecules and developmental and catastrophic neuron death. A variety of experimental approaches support a causal role for such changes in the death process and are beginning to indicate how the neuronal E2F pathway activates the core apoptotic machinery. The discovery and elaboration of the neuronal apoptotic E2F pathway provides abundant targets as well as small molecule candidates for potential therapeutic intervention in nervous system trauma and degenerative disease. PMID:14647236

Greene, L A; Biswas, S C; Liu, D X

2004-01-01

233

Atypical E2F activity coordinates PHR1 photolyase gene transcription with endoreduplication onset  

PubMed Central

Because of their sessile life style, plants have evolved the ability to adjust to environmentally harsh conditions. An important aspect of stress adaptation involves the reprogramming of the cell cycle to ensure optimal growth. The atypical E2F transcription factor DP-E2F-like 1 (E2Fe/DEL1) had been found previously to be an important regulator of the endocycle onset. Here, a novel role for E2Fe/DEL1 was identified as a transcriptional repressor of the type-II cyclobutane pyrimidine dimer-photolyase DNA repair gene PHR1. Upon ultraviolet-B (UV-B) treatment, plants knocked out for E2Fe/DEL1 had improved DNA repair abilities when compared with control plants, whereas those overexpressing it performed less well. Better DNA repair allowed E2Fe/DEL1 knockout plants to resume endoreduplication faster than control plants, contributing in this manner to UV-B radiation resistance by compensating the stress-induced reduction in cell number by ploidy-dependent cell growth. As E2Fe/DEL1 levels decreased upon UV-B treatment, we hypothesize that the coordinated transcriptional induction of PHR1 with the endoreduplication onset contributes to the adaptation of plants exposed to UV-B stress. PMID:21131907

Radziejwoski, Amandine; Vlieghe, Kobe; Lammens, Tim; Berckmans, Barbara; Maes, Sara; Jansen, Marcel A K; Knappe, Claudia; Albert, Andreas; Seidlitz, Harald K; Bahnweg, Gunther; Inze, Dirk; De Veylder, Lieven

2011-01-01

234

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

235

How alkyl halide structure affects E2 and SN2 reaction barriers: E2 reactions are as sensitive as SN2 reactions.  

PubMed

High-level electronic structure calculations, including a continuum treatment of solvent, are employed to elucidate and quantify the effects of alkyl halide structure on the barriers of SN2 and E2 reactions. In cases where such comparisons are available, the results of these calculations show close agreement with solution experimental data. Structural factors investigated include ?- and ?-methylation, adjacency to unsaturated functionality (allyl, benzyl, propargyl, ? to carbonyl), ring size, and ?-halogenation and cyanation. While the influence of these factors on SN2 reactivity is mostly well-known, the present study attempts to provide a broad comparison of both SN2 and E2 reactivity across many cases using a single methodology, so as to quantify relative reactivity trends. Despite the fact that most organic chemistry textbooks say far more about how structure affects SN2 reactions than about how it affects E2 reactions, the latter are just as sensitive to structural variation as are the former. This sensitivity of E2 reactions to structure is often underappreciated. PMID:24437451

Rablen, Paul R; McLarney, Brett D; Karlow, Brandon J; Schneider, Jean E

2014-02-01

236

Analysis of the human E2 ubiquitin conjugating enzyme protein interaction network.  

PubMed

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 approximately 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

2009-10-01

237

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

238

E1-E2 interactions in ubiquitin and Nedd8 ligation pathways.  

PubMed

Initial rates of E1-catalyzed E2 transthiolation have been used as a reporter function to probe the mechanism of 125I-ubiquitin transfer between activation and ligation half-reactions of ubiquitin conjugation. A functional survey of 11 representative human E2 paralogs reveals similar Km for binding to human Uba1 ternary complex (Km(ave)=121±72 nm) and kcat for ubiquitin transfer (kcat(ave)=4.0±1.2 s(-1)), suggesting that they possess a conserved binding site and transition state geometry and that they compete for charging through differences in intracellular concentration. Sequence analysis and mutagenesis localize this binding motif to three basic residues within Helix 1 of the E2 core domain, confirmed by transthiolation kinetics. Partial conservation of the motif among E2 paralogs not recognized by Uba1 suggests that another factor(s) account for the absolute specificity of cognate E2 binding. Truncation of the Uba1 carboxyl-terminal ?-grasp domain reduces cognate Ubc2b binding by 31-fold and kcat by 3.5×10(4)-fold, indicating contributions to E2 binding and transition state stabilization. Truncation of the paralogous domain from the Nedd8 activating enzyme has negligible effect on cognate Ubc12 transthiolation but abrogates E2 specificity toward non-cognate carrier proteins. Exchange of the ?-grasp domains between ubiquitin and Nedd8 activating enzymes fails to reverse the effect of truncation. Thus, the conserved Helix 1 binding motif and the ?-grasp domain direct general E2 binding, whereas the latter additionally serves as a specificity filter to exclude charging of non-cognate E2 paralogs in order to maintain the fidelity of downstream signaling. PMID:22069333

Tokgöz, Zeynep; Siepmann, Thomas J; Streich, Frederick; Kumar, Brajesh; Klein, Jennifer M; Haas, Arthur L

2012-01-01

239

E2F transcription factors and digestive system malignancies: How much do we know?  

PubMed Central

The E2F proteins comprise a family of 8 members that function as transcription factors. They are key targets of the retinoblastoma protein (RB) and were initially divided into groups of activators and repressors. Accumulating data suggest that there is no specific role for each individual E2F member. Instead, each E2F can exert a variety of cellular effects, some of which represent opposing ones. For instance, specific E2Fs can activate transcription and repression, promote or hamper cell proliferation, augment or inhibit apoptosis, all being dependent on the cellular context. This complexity reflects the importance that these transcription factors have on a cell’s fate. Thus, delineating the specific role for each E2F member in specific malignancies, although not easy, is a challenging and continuously pursued task, especially in view of potential E2F targeted therapies. Therefore, several reviews are continuously trying to evaluate available data on E2F status in various malignancies. Such reviews have attempted to reach a consensus, often in the simplistic form of oncogenes or tumor suppressor genes for the E2Fs. However they frequently miss spatial and temporal alterations of these factors during tumor development, which should also be considered in conjunction with the status of the regulatory networks that these factors participate in. In the current ‘‘Letter to the Editor’’, we comment on the flaws, misinterpretations and omissions in one such review article published recently in the World Journal of Gastroenterology regarding the role of E2Fs in digestive system malignancies. PMID:25110451

Evangelou, Konstantinos; Havaki, Sophia; Kotsinas, Athanassios

2014-01-01

240

Correlation between the quenching of total GT+ strength and the increase of E2 strength  

E-print Network

Relations between the total beta+ Gamow-Teller (GT+) strength and the E2 strength are further examined. It is found that in shell-model calculations for N=Z nuclei, in which changes in deformation are induced by varying the single-particle energies, the total GT+ or GT- strength decreases monotonically with increasing values of the B(E2) from the ground state to the first excited J=2+ state. Similar trends are also seen for the double GT transition amplitude (with some exceptions) and for the spin part of the total M1 strength as a function of B(E2).

N. Auerbach; D. C. Zheng; L. Zamick; B. A. Brown

1993-01-21

241

Protein ubiquitination involving an E1-E2-E3 enzyme ubiquitin thioester cascade  

Microsoft Academic Search

UBIQUITINATION of proteins involves the concerted action of the El ubiquitin-activating enzyme, E2 ubiquitin-conjugating enzymes and E3 ubiquitin-protein 1igases1-3. It has been proposed that E3s function as 'docking proteins', specifically binding substrate proteins and specific E2s, and that ubiquitin is then transferred directly from E2s to substrates1-5. We show here that formation of a ubiquitin thioester on E6-AP, an E3

Martin Scheffner; Ulrike Nuber; Jon M. Huibregtse

1995-01-01

242

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

243

Structure of the CIAP2 Ring Domain Reveal Conformational Changes Associated With E2 Recruitment  

SciTech Connect

Inhibitor of apoptosis (IAP) proteins are key negative regulators of cell death that are highly expressed in many cancers. Cell death caused by antagonists that bind to IAP proteins is associated with their ubiquitylation and degradation. The RING domain at the C terminus of IAP proteins is pivotal. Here we report the crystal structures of the cIAP2 RING domain homodimer alone, and bound to the ubiquitin-conjugating (E2) enzyme UbcH5b. These structures show that small changes in the RING domain accompany E2 binding. By mutating residues at the E2-binding surface, we show that autoubiquitylation is required for regulation of IAP abundance. Dimer formation is also critical, and mutation of a single C-terminal residue abrogated dimer formation and E3 ligase activity was diminished. We further demonstrate that disruption of E2 binding, or dimerization, stabilizes IAP proteins against IAP antagonists in vivo.

Mace, P.D.; Linke, K.; Feltham, R.; Schumacher, F.-R.; Smith, C.A.; Vaux, D.L.; Silke, J.; Day, C.L.

2009-05-19

244

Understanding the self-assembly mechanism of E2 protein cage and exploring its potential applications.  

E-print Network

??Self-assembly protein cages have drawn much attention for their applications in nanotechnology. E2 protein from Bacillus stearothermophilus, which comprises 60 identical subunits to form hollow… (more)

Tao, Peng.

2013-01-01

245

On Probabilities of E2 Transitions between Positive-Parity States in ^160Dy Nucleus  

E-print Network

Reduced probabilities B(E2) of \\gamma transitions between states of positive parity in the ^160Dy nucleus are calculated within the framework of the interacting boson model (IBM-1). The results are compared with the experimental data.

J. Adam; V. P. Garistov; M. Honusek; J. Dobes; I. Zvolski; J. Mrazek; A. A. Solnyshkin

2004-08-21

246

[Trends in Evolutionary Biology 2010; 2:e2] [page 7] Multiple approaches to study  

E-print Network

[Trends in Evolutionary Biology 2010; 2:e2] [page 7] Multiple approaches to study color pattern evolution in butterflies Antónia Monteiro and Kathleen L. Prudic Ecology and Evolutionary Biology, Yale

Monteiro, Antónia

247

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

248

Tower Spectral Sequences and the Homotopy Automorphisms of E2-operads  

E-print Network

) parenthesized braid operad B(PaB)+ as working model of a (unitary) E2-operad, rather than the (unitary) little 2 of the (unitary) operad of little 2-discs D2+. We have an identity hAutSimp Op (E2+) GT(Q) SO(2) in the homotopy of the topological little 2-discs operad D2+, and given by the rotation action of the ambient unit disc D2

Fresse, Benoit

249

Identification of E2F1 as a positive transcriptional regulator for ?-catenin  

Microsoft Academic Search

?-Catenin is upregulated in human carcinomas. However, little is known about the potential transcriptional factors that regulate ?-catenin expression in cancer. Using a human ?-catenin reporter system, we have screened several nuclear signaling modulators to test whether they can affect ?-catenin transcription. Among ?-catenin\\/LEF-1, Notch1, and E2F1, E2F1 dramatically increased ?-catenin–luciferase activities while ?-catenin\\/LEF-1 induced only a marginal increase. Rb

Kwonseop Kim; Minsoo Oh; Hyunkyoung Ki; Tao Wang; Sonja Bareiss; M. Elizabeth. Fini; Dawei Li; Qun Lu

2008-01-01

250

Prostaglandin E 2 depresses solitary tract-mediated synaptic transmission in the nucleus tractus solitarius  

Microsoft Academic Search

Prostaglandin E2 (PGE2) is a prototypical inflammatory mediator that excites and sensitizes cell bodies [Kwong K, Lee LY (2002) PGE2 sensitizes cultured pulmonary vagal sensory neurons to chemical and electrical stimuli. J Appl Physiol 93:1419–1428; Kwong K, Lee LY (2005) Prostaglandin E2 potentiates a tetrodotoxin (TTX)-resistant sodium current in rat capsaicin-sensitive vagal pulmonary sensory neurons. J Physiol 56:437–450] and peripheral

N. Laaris; D. Weinreich

2007-01-01

251

Viral E1 and E2 Proteins Support Replication of Homologous and Heterologous Papillomaviral Origins  

Microsoft Academic Search

We have shown that E1 and E2 proteins of human papillomavirus type 11 (HPV-11) were essential to support the replication of the homologous viral origin (ori) in a transient replication assay, similar to reports on bovine papillomavirus type 1 (BPV-1). Unexpectedly, matched or even mixed combinations of E1 and E2 proteins from HPV-11 or BPV-1 replicated either ori in human,

Cheng-Ming Chiang; Mart Ustav; Arne Stenlund; Thau F. Ho; Thomas R. Broker; Louise T. Chow

1992-01-01

252

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

Microsoft Academic Search

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

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

2008-01-01

253

E2–c-Cbl Recognition Is Necessary but not Sufficient for Ubiquitination Activity  

Microsoft Academic Search

The E2 ubiquitin-conjugating enzymes UbcH7 and UbcH5B both show specific binding to the RING (really interesting new gene) domain of the E3 ubiquitin-protein ligase c-Cbl, but UbcH7 hardly supports ubiquitination of c-Cbl and substrate in a reconstituted system. Here, we found that neither structural changes nor subtle differences in the E2–E3 interaction surface are possible explanations for the functional specificity

Anding Huang; Rob N. de Jong; Hans Wienk; G. Sebastiaan Winkler; H. Th. Marc Timmers; Rolf Boelens

2009-01-01

254

Lysine activation and functional analysis of E2-mediated conjugation in the SUMO pathway  

Microsoft Academic Search

E2 conjugating proteins that transfer ubiquitin and ubiquitin-like modifiers to substrate lysine residues must first activate the lysine nucleophile for conjugation. Genetic complementation revealed three side chains of the E2 Ubc9 that were crucial for normal growth. Kinetic analysis revealed modest binding defects but substantially lowered catalytic rates for these mutant alleles with respect to wild-type Ubc9. X-ray structures for

Ali A Yunus; Christopher D Lima

2006-01-01

255

The rubella virus E2 and E1 spike glycoproteins are targeted to the Golgi complex  

Microsoft Academic Search

Rubella virus (RV) has been reported to bud from intracellular membranes in certain cell types. In this study the intracellular site of targeting of RV envelope E2 and E1 glycoproteins has been inves- tigated in three different cell types (CHO, BHK-21 and Vero cells) transfected with a cDNA encoding the two glycoproteins. By indirect immunofluorescence, E2 and E1 were localized

Tom C. Hobman; Luann Woodward; Marilyn Gist Farquhar

1993-01-01

256

Conserved functions of the pRB and E2F families  

Microsoft Academic Search

Proteins that are related to the retinoblastoma tumour suppressor pRB and the E2F transcription factor are conserved in many species of plants and animals. The mammalian orthologues of pRB and E2F are best known for their roles in cell proliferation, but it has become clear that they affect many biological processes. Here we describe the functions of pRB-related proteins and

Sander van den Heuvel; Nicholas J. Dyson

2008-01-01

257

Radiation physics simulator for space X-ray observatory Astro-E2  

Microsoft Academic Search

We constructed a Monte-Carlo simulator framework for the radiation environment of Astro-E2, the Japanese 5th X-ray astronomy satellite. We used Geant4 as the simulator engine, and embedded it into the analysis framework derived from what has been used for other Astro-E2 software development. The entire architecture is designed to make the learning cost of the framework programming as low as

M. Ozaki; S. Watanabe; Y. Terada; T. Itoh; M. Kitsunezuka; Y. Ishisaki; T. Takahashi

2004-01-01

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

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

E-print Network

REGULATION OF E2F-1 GENE EXPRESSION IN HUMAN BREAST CANCER CELLS A Dissertation by SHARON KHETHIWE NGWENYA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of DOCTOR OF PHILOSOPHY May 2005 Major Subject: Biochemistry REGULATION OF E2F-1 GENE EXPRESSION IN HUMAN BREAST CANCER CELLS A Dissertation by SHARON KHETHIWE NGWENYA Submitted to Texas A&M University in partial...

Ngwenya, Sharon Khethiwe

2005-08-29

260

[Pattern of plasma sex steroid hormone levels during the breeding season of male and female skink: Eumeces chinensis].  

PubMed

Changes in gonadal activity and plasma sex steroid hormone levels in male and female Eumece chinensis during the breeding season were described. The results showed that: The vitellogensis of follicles of female Eumeces chinensis needed the stimulation of 17beta-estradiol (E2). As ovary masses reached peak values between late April and mid-May, E2 levels rose to the top value by late March, and then sharply declined but went up again before preovulation; The physiological functions of plasma progesterone (P) consisted in its oviductal egg retention, embryo development, and eggshell formation. P levels fluctuated near the basic value between mid-March and late April. In mid-May, with the onset of ovulation, plasma P levels rose rapidly, reached peak value by late May and declined sharply after ovulation. Plasma E2 levels declined as plasma P levels rose, showing an inverse relationship between them; In males, plasma Testosterone (T) levels were closely correlated with the maintenance of spermatogenesis activities, male and male combat, sexual display, and mating. Plasma T levels tended to rise after the termination of hibernation, and reached peak value by mid-April. After mid-May, with the testis aggressing, plasma T levels gradually went down and reached bottom value by late June. PMID:15789762

Hu, Jian Rao; Du, Ji Zeng; Ji, Xiang

2004-12-01

261

Effect of neonatal rat bisphenol a exposure on performance in the Morris water maze.  

PubMed

Bisphenol A (BPA), an environmental estrogen, is a component of many food and beverage containers and can leach into the container contents over time. Due to its estrogenic properties, exposure to BPA during development could alter the appropriate maturation of pathways essential for normal cognitive function at later ages. To investigate this, the effects of repeated postnatal exposure of male and female rats to BPA on spatial learning and memory were investigated using a Morris water maze. Breeders and offspring were maintained on a standard phytoestrogen-free diet. Oral administration of 72 microg/kg 17 beta-estradiol (E(2)), 100 microg/kg BPA (low BPA), 250 microg/kg BPA (high BPA), or the safflower oil vehicle was performed daily from postnatal d 1 (PND1) through PND14. There were no treatment-related effects on swimming ability or motivation (PND33) or on acquisition of maze solution (PND34-37). However, acquisition of maze performance was significantly better in control males than in control females. Treatment with E(2) and low BPA disrupted this normal gender-dependent pattern of acquisition, while treatment with high BPA did not. In a probe trial (PND40), females treated with high BPA spent significantly less time in the escape quadrant. These data indicate that E(2) and low dosages of BPA can alter the normal gender-dependent pattern of acquisition, while higher dosages of BPA alter the retention of spatial information without significantly affecting acquisition. PMID:14555403

Carr, Russell; Bertasi, Frances; Betancourt, Angela; Bowers, Susan; Gandy, B Scott; Ryan, Peter; Willard, Scott

2003-11-14

262

Hormone dependency of human breast neoplasms cultured in vitro in the stem cell assay.  

PubMed

The stem cell soft agar culture system provides a biological tool with which to study tumor clones derived from heterogeneous tumor cell populations. For testing the feasibility of this approach in identifying hormone-responsive clones of mammary tumors, a study was done to determine whether estrogen deprivation or supplementation would alter colony formation in sequential breast neoplasms received in the Cell Kinetics Laboratory, The Pennsylvania State University. Single-cell suspensions obtained from 22 freshly excised breast neoplasms (20 malignant, 2 benign) were plated in soft agar with and without tamoxifen (Tam) (10(-7) M) with the use of serum-supplemented media and with and without 17 beta-estradiol (E2) (10(-8) M] under serum-free medium conditions. Twenty tumors successfully grew, producing 42 +/- 8 (mean +/- SEM) colonies in control dishes in the presence of serum and 27 +/- 5 in its absence (P less than .001). Tam inhibited colony formation in 78% of malignant tumors, whereas a stimulatory effect was observed with E2 in 94%. An increase in colony formation was induced by Tam in 4 tumors (2 benign and 2 malignant). The effects of E2 and Tam on tumor growth were not influenced by the estrogen and progesterone receptor status of the tumor. These preliminary results suggest that all tumors, irrespective of their receptor status, may contain clones of hormone-responsive cells. PMID:2985856

Manni, A; Wright, C; Pontari, M; Feil, P; Joehl, R

1985-04-01

263

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

264

Evidence for the presence of sex steroid hormones in Zhikong scallop, Chlamys farreri.  

PubMed

To obtain evidence of the presence of sex steroid hormones in mollusks, hormone variation in the gonads of the Zhikong scallop Chlamys farreri was analyzed using UPLC-MS/MS. These were found, as expected, with concentrations of estrone (E1), 17beta-estradiol (E2), and testosterone (T) in the testes ranging from not detected (ND) to 0.07 ± 0.10, ND to 3.10 ± 2.00, and ND to 2.67 ± 1.55 ng/g wet weight, respectively. In the ovaries, these hormones ranged from ND to 2.45 ± 1.22, ND to 27.90 ± 4.23, and ND to 2.38 ± 1.56 ng/g ww, respectively. The levels of T in males and E2 in females followed a trend similar to the gonadal-somatic index over the course of the reproductive period. In addition, the gene expression of vitellogenin and calmodulin-2 showed similar patterns to T and E2, while the estrogen receptors and calmodulin-1 did not. These results indicate that sex steroids are present in the scallop and that they may regulate endocrine functions during the reproductive process. PMID:24662324

Zheng, Bing-Hui; An, Li-Hui; Chang, Hong; Liu, Ying; Jiang, Zhi-Qiang

2014-09-01

265

Structural and Antigenic Definition of Hepatitis C Virus E2 Glycoprotein Epitopes Targeted by Monoclonal Antibodies  

PubMed Central

Hepatitis C virus (HCV) is the major cause of chronic liver disease as well as the major indication for liver transplantation worldwide. Current standard of care is not completely effective, not administrable in grafted patients, and burdened by several side effects. This incomplete effectiveness is mainly due to the high propensity of the virus to continually mutate under the selective pressure exerted by the host immune response as well as currently administered antiviral drugs. The E2 envelope surface glycoprotein of HCV (HCV/E2) is the main target of the host humoral immune response and for this reason one of the major variable viral proteins. However, broadly cross-neutralizing monoclonal antibodies (mAbs) directed against HCV/E2 represent a promising tool for the study of virus-host interplay as well as for the development of effective prophylactic and therapeutic approaches. In the last few years many anti-HCV/E2 mAbs have been evaluated in preclinical and clinical trials as possible candidate antivirals, particularly for administration in pre- and post-transplant settings. In this review we summarize the antigenic and structural characteristics of HCV/E2 determined through the use of anti-HCV/E2 mAbs, which, given the absence of a crystal structure of this glycoprotein, represent currently the best tool available. PMID:23935648

Tarr, Alexander W.; Mancini, Nicasio; Clementi, Massimo

2013-01-01

266

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

267

The rubella virus E2 and E1 spike glycoproteins are targeted to the Golgi complex  

PubMed Central

Rubella virus (RV) has been reported to bud from intracellular membranes in certain cell types. In this study the intracellular site of targeting of RV envelope E2 and E1 glycoproteins has been investigated in three different cell types (CHO, BHK-21 and Vero cells) transfected with a cDNA encoding the two glycoproteins. By indirect immunofluorescence, E2 and E1 were localized to the Golgi region of all three cell types, and their distribution was disrupted by treatment with BFA or nocodazole. Immunogold labeling demonstrated that E2 and E1 were localized to Golgi cisternae and indicated that the glycoproteins were distributed across the Golgi stack. Analysis of immunoprecipitates obtained from stably transfected CHO cells revealed that E2 and E1 become endo H resistant and undergo sialylation without being transported to the cell surface. Transport of RV glycoproteins to the Golgi complex was relatively slow (t1/2 = 60-90 min). Coprecipitation experiments indicated that E2 and E1 form a heterodimer in the RER. E1 was found to fold much more slowly than E2, suggesting that the delay in transport of the heterodimer to the Golgi may be due to the slow maturation of E1 in the ER. These results indicate that RV glycoproteins behave as integral membrane proteins of the Golgi complex and thus provide a useful model to study targeting and turnover of type I membrane proteins in this organelle. PMID:8468347

1993-01-01

268

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

269

Theoretical study of bimolecular elimination (E2) reactions. Possibility of syn E2 elimination in the series of 2-R-2-R'-1-halocyclopropanes  

Microsoft Academic Search

Reactions of the methoxide ion with substituted halocyclopropanes, which result in E2 elimination, have been studied by the semiempirical quantum-chemical AM1 method. The transition states corresponding totrans andcis routes have been localized. The energetic predominance of thetrans route over thecis route is reduced by 2.6 kcal mol-1 on going from 1-chloropropane to chlorocyclopropane because of the features of cyclopropane geometry.

L. V. Ermolaeva; S. A. Appolonova; V. V. Plemenkov; I. G. Bolesov; A. I. Konovalov

1995-01-01

270

Glutamate183 in the conserved TGES motif of domain A of sarcoplasmic reticulum Ca2+ATPase assists in catalysis of E2\\/E2P partial reactions  

Microsoft Academic Search

The recently determined crystal structures of the sarcoplasmic reticulum Ca2+-ATPase show that in the E1Ca2 form, domain A is almost isolated from the other cytoplasmic domains, P and N, whereas in E2, domain A has approached domains P and N, with E183 of the highly conserved P-type ATPase signature sequence TGES in domain A now being close to the phosphorylated

Johannes D. Clausen; Bente Vilsen; David B. McIntosh; Anja P. Einholm; Jens Peter Andersen

2004-01-01

271

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

PubMed Central

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

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

2014-01-01

272

Brd4-Mediated Nuclear Retention of the Papillomavirus E2 Protein Contributes to Its Stabilization in Host Cells  

PubMed Central

Papillomavirus E2 is a multifunctional viral protein that regulates many aspects of the viral life cycle including viral episome maintenance, transcriptional activation, and repression. E2 is degraded by the ubiquitin-proteasome pathway. Cellular bromodomain protein Brd4 has been implicated in the stabilization of the E2 protein. E2 normally shuttles between the cytoplasm and the nucleus. In this study, we demonstrate that E2 ubiquitylation mostly occurs in the cytoplasm. We also find that the interaction with Brd4 promotes nuclear retention of papillomavirus E2 proteins and contributes to their stabilization in the nucleus. Compared to wild type E2 proteins, nuclear-localization-defective mutants are rapidly degraded by the ubiquitin-proteasome pathway; however, co-expression of Brd4 redirects these mutants into the nucleus and significantly increases their stability. We further demonstrate that tethering E2 proteins to chromatin as either double-bromodomain fusion proteins or histone 2B (H2B) fusion proteins significantly stabilizes the E2 proteins. Our studies suggest that chromatin recruitment of the E2 protein via interaction with Brd4 prevents E2 ubiquitylation and proteasomal degradation in the cytoplasm, leading to its stabilization in the nucleus. These studies bring new insights for understanding Brd4-mediated E2 stabilization, and provide an additional mechanism by which the chromatin-associated Brd4 regulates E2 functions. PMID:24448221

Li, Jing; Li, Qing; Diaz, Jason; You, Jianxin

2014-01-01

273

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

274

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

275

Identification of E2F1 as a positive transcriptional regulator for ?-catenin  

PubMed Central

?-Catenin is upregulated in human carcinomas. However, little is known about the potential transcriptional factors that regulate ?-catenin expression in cancer. Using a human ?-catenin reporter system, we have screened several nuclear signaling modulators to test whether they can affect ?-catenin transcription. Among ?-catenin/LEF-1, Notch1, and E2F1, E2F1 dramatically increased ?-catenin-luciferase activities while ?-catenin/LEF-1 induced only a marginal increase. Rb suppressed the upregulation of ?-catenin-luciferase activities induced by E2F1 but did not interact with ?-catenin. RT-PCR and Western blot analyses in 4 different prostate cancer cell lines revealed that regulation of ?-catenin expression is controlled mainly at the transcriptional level. Interestingly, the effects of E2F1 on ?-catenin expression were observed only in human cancer cells expressing abundant endogenous ?-catenin. These studies identify E2F1 as a positive transcriptional regulator for ?-catenin, but further suggest the presence of strong negative regulator(s) for ?-catenin in prostate cancer cells with minimal endogenous ?-catenin expression. PMID:18302937

Kim, Kwonseop; Oh, Minsoo; Ki, Hyunkyoung; Wang, Tao; Bareiss, Sonja; Fini, M. Elizabeth; Li, Dawei; Lu, Qun

2008-01-01

276

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

277

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

PubMed

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

2014-03-01

278

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

SciTech Connect

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

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

2009-03-27

279

Apolipoprotein E ?4 is superior to apolipoprotein E ?2 in predicting cognitive scores over 30 months  

PubMed Central

Background The purpose of this study was to compare apolipoprotein E ?4 (Apo E ?4) and apolipoprotein E ?2 (Apo E ?2) as predictors of cognitive and functional trajectories over 30 months. Methods This prospective cohort study included 287 community-dwelling memory clinic patients with dementia, mild cognitive impairment, or no cognitive impairment. The Addenbrooke Cognitive Examination, Mini-Mental State Examination, Montreal Cognitive Assessment, Delirium Index, and Nottingham Instrumental Activities of Daily Living tests were administered to each subject. Results One hundred and nine subjects (40%) carried Apo E ?4 and 48 (16.7%) carried Apo E ?2. One hundred and nine ?4-positive subjects differed significantly from 178 ?4-negative subjects in 19/52 comparisons (36.5%), whereas 46 Apo E ?2-positive subjects had 0/52 significant differences from 239 ?2-negative subjects (P < 0.0001). The variables most affected by ?4 were the Delirium Index and Mini-Mental State Examination. Instrumental Activities of Daily Living score and residence were unrelated to Apo E ?4 or ?2. Conclusion Apo E ?4 positivity predicted four cognitive scores measured every 6 months over 30 months. Apo E ?2 scores predicted none of 52 comparisons. PMID:24204131

Regal, Paul; Nair, Balakrishnan; Hetherington, Eileen

2013-01-01

280

Chylomicron remnant uptake in the livers of mice expressing human apolipoproteins E3, E2  

E-print Network

cause chylomicron remnant accumulation (type III hyperlipidemia). However, the degree of dyslipidemia and its penetrance are different in humans and mice. Remnant uptake by isolated liver from apoE?/ ? mice transgenic for human apoE2, apoE3-Leiden, or apoE3 was measured. In the presence of both LDL receptor (LDLR) and LDL receptor-related protein (LRP), remnant uptake was apoE3?E3-Leiden?E2 mice. Absence of LDLR reduced uptake in apoE3 and apoE3-Leiden-secreting livers but not in apoE2-secreting livers. LRP inhibition with receptor-associated protein reduced uptake in apoE3- and apoE2–secreting livers, but not in apoE3-Leiden–secreting livers, regardless of the presence of LDLR. Fluorescently labeled remnants clustered with LRP in apoE3secreting livers only in the absence of LDLR, but clustered in livers that expressed apoE2 even in the presence of LDLR, and

Abstract Apolipoprotein E (apoe

281

Acetylation of Conserved Lysines in Bovine Papillomavirus E2 by p300  

PubMed Central

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

2013-01-01

282

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

PubMed Central

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

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

2010-01-01

283

Expression of type III hyperlipoproteinemia in apolipoprotein E2 (Arg158 --> Cys) homozygotes is associated with hyperinsulinemia  

Microsoft Academic Search

Type III hyperlipoproteinemia (HLP) is mainly found in homozygous carriers of apolipoprotein E2 (apoE2, Arg158-->Cys). Only a small percentage (< 5%) of these apoE2 homozygotes develops hyperlipidemia, indicating that additional environmental and genetic factors contribute to the expression of type III HLP. In the present study, first, the prevalence of type III HLP among apoE2 homozygotes was estimated in a

A. F. Stalenhoef; Nicoline Hoogerbrugge; J. A. Gevers Leuven; Duijn van C. M; Louis M. Havekes; Augustinus H. M. Smelt

2002-01-01

284

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

Microsoft Academic Search

BACKGROUND: We demonstrated that E2 conjugated to BSA (E2BSA) induces a rapid membrane-initiated inhibition of LH secretion followed hours later by a slight increase in LH secretion. Whether these actions of E2BSA are restricted to the pituitary gland and whether the membrane-initiated pathway of E2BSA contributes to the up-regulation of the number of GnRH receptors during the positive feedback effect

J Alejandro Arreguin-Arevalo; Ryan L Ashley; Elizabeth R Wagenmaker; Amy E Oakley; Fred J Karsch; Terry M Nett

2010-01-01

285

The Role of DNA Structure and Dynamics in the Recognition of Bovine Papillomavirus E2 Protein Target Sequences  

Microsoft Academic Search

The papillomavirus E2 transcription and replication factors bind to the DNA consensus ACCGN4CGGT sequence (E2-BS), through both direct and indirect readout mechanisms. The two symmetric half-sites ACCG·CGGT are highly conserved in the genomes and are hydrogen bound with E2. Although E2 does not contact the N4 spacer, the affinities are modulated by the base composition of this DNA part. Nevertheless,

D. Djuranovic; C. Oguey; B. Hartmann

2004-01-01

286

Release of deuterated (E)-2-nonenal during beer aging from labeled precursors synthesized before boiling.  

PubMed

Although lipid autoxidation in the boiling kettle is a key determinant of the cardboard flavor of aged beers, recent results show that mashing is another significant source of wort nonenal potential, the well-known indicator of how a beer will release (E)-2-nonenal during storage. Although unstable, deuterated (E)-2-nonenal nitrogen adducts created during mashing can in some cases partially persist in the pitching wort, to release deuterated (E)-2-nonenal during beer aging. In the experiment described here, the relative contributions of mashing and boiling were estimated at 30 and 70%, respectively. The presence of oxygen during mashing and, to a lesser extent, high lipoxygenase activity can intensify the stale cardboard flavor. PMID:12475282

Liégeois, Catherine; Meurens, Nicolas; Badot, Camille; Collin, Sonia

2002-12-18

287

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

288

Intermediate-energy Coulomb excitation of 104Sn: Moderate E2 strength decrease approaching 100Sn  

E-print Network

The reduced transition probability B(E2) of the first excited 2+ state in the nucleus 104Sn was measured via Coulomb excitation in inverse kinematics at intermediate energies. A value of 0.163(26) e^2b^2 was extracted from the absolute cross-section on a Pb target, while the method itself was verified with the stable 112Sn isotope. Our result deviates significantly from the earlier reported value of 0.10(4) e^2b^2 and corresponds to a moderate decrease of excitation strength relative to the almost constant values observed in the proton-rich, even-A 106-114Sn isotopes. Present state-of-the-art shell-model predictions, which include proton and neutron excitations across the N=Z=50 shell closures as well as standard polarization charges, underestimate the experimental findings

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

2013-01-01

289

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.

Nayak, R C

2014-01-01

290

B(E2) Evaluation for 0+ to 2+ Transitions in Even-Even Nuclei  

E-print Network

A collaborative study by Brookhaven-McMaster-Central Michigan is underway to evaluate B(E2)$\\uparrow$ for 0$^{+}_{1}$ $\\rightarrow$ 2$^{+}_{1}$ 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)$\\uparrow$ 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;0$^{+}_{1}$ $\\rightarrow$ 2$^{+}_{1}$) evaluation project are also described.

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

2013-02-27

291

Intermediate-energy Coulomb excitation of 104Sn: Moderate E2 strength decrease approaching 100Sn  

E-print Network

The reduced transition probability B(E2) of the first excited 2+ state in the nucleus 104Sn was measured via Coulomb excitation in inverse kinematics at intermediate energies. A value of 0.163(26) e^2b^2 was extracted from the absolute cross-section on a Pb target, while the method itself was verified with the stable 112Sn isotope. Our result deviates significantly from the earlier reported value of 0.10(4) e^2b^2 and corresponds to a moderate decrease of excitation strength relative to the almost constant values observed in the proton-rich, even-A 106-114Sn isotopes. Present state-of-the-art shell-model predictions, which include proton and neutron excitations across the N=Z=50 shell closures as well as standard polarization charges, underestimate the experimental findings

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

2013-05-13

292

A novel peptide that inhibits E2F transcription and regresses prostate tumor xenografts  

PubMed Central

E2F-1, a key transcription factor necessary for cell growth, DNA repair and differentiation, is an attractive target for development of useful anticancer drugs in tumors that are E2F “oncogene addicted”. A peptide, isolated from phage clones, based on its binding to an E2F-1 consensus sequence, was cytotoxic against a wide range of cancer cell lines. The peptide was coupled to penetratin (PEP) and tested against prostate cancer cell lines. As the PEP was found to be relatively unstable in serum, it was encapsulated in PEGylated liposomes for in vivo studies. The peptide was cytotoxic against prostate cell lines at low micromolar concentrations. Treatment of mice bearing the human Du-145 human prostate tumor with the PEP encapsulated in PEGylated liposomes (PL-PEP) caused tumor regression without significant toxicity. The liposome encapsulated PEP has promise as an antitumor agent, alone or in combination with inhibitors of DNA synthesis. PMID:24658650

Xie, Xiaoqi; Bansal, Nitu; Shaik, Tazeem; Kerrigan, John E.; Minko, Tamara; Garbuzenko, Olga; Abali, Emine Ercikan; Johnson-Farley, Nadine; Banerjee, Debabrata; Scotto, Kathleen W.; Bertino, Joseph R

2014-01-01

293

JNK-mediated turnover and stabilization of the transcription factor p45/NF-E2 during differentiation  

E-print Network

and phosphorylates its Ser157 residue. This reaction leads to the poly-ubiquitination of p45/NF-E2 at one or moreJNK-mediated turnover and stabilization of the transcription factor p45/NF-E2 during characterized the signal transduction pathways regulating the catabolisis of p45/NF-E2, a bZIP factor activating

Tsai, Ming-Daw

294

Reactions of r-Nucleophiles with Alkyl Chlorides: Competition between SN2 and E2 Mechanisms and the  

E-print Network

Reactions of r-Nucleophiles with Alkyl Chlorides: Competition between SN2 and E2 Mechanisms (SN2) and base-induced elimination (E2). As the extent of substitution in the neutral reactants of the E2 channel. These results are in excellent agreement with previously reported trends

Lineberger, W. Carl

295

Imperial College London EEE 1L6 Autumn 2009 E2.2 Analogue Electronics Multiple stage amplifiers  

E-print Network

Imperial College London ­ EEE 1L6 Autumn 2009 E2.2 Analogue Electronics Multiple stage amplifiers amplifiers #12;Imperial College London ­ EEE 2L6 Autumn 2009 E2.2 Analogue Electronics Two stage BJT ­ EEE 3L6 Autumn 2009 E2.2 Analogue Electronics Differential amplifier · Half circuit (i.e. driven from

Papavassiliou, Christos

296

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.

297

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

298

Determinants of RING-E2 Fidelity for Hrd1p, a Membrane-anchored Ubiquitin Ligase*S  

E-print Network

Determinants of RING-E2 Fidelity for Hrd1p, a Membrane-anchored Ubiquitin Ligase*S Received of a particular E2 ubiquitin-conjugating enzyme to accomplish ubiquitination of a substrate. We examined the requirements for correct E2-E3 specificity in the RING-H2 ubiquitin ligase Hrd1p, an ER-localized protein known

Hampton, Randy

299

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

300

Transcription Factors ETF, E2F, and SP-1 Are Involved in Cytokine-Independent Proliferation of Murine  

E-print Network

Transcription Factors ETF, E2F, and SP-1 Are Involved in Cytokine-Independent Proliferation-regulated. The latter genes showed an overrepresen- tation of transcription factor binding sites (TFBS) for ETF (TEA hepatectomy con- tained overrepresented TFBS for ETF, E2F1, and SP-1 and displayed increased expression of E2F

Timmer, Jens

301

Prevention of chemical carcinogen DNA binding and inhibition of nuclear RNA polymerase activity by organosulfur compounds as the possible mechanisms for their anticancer initiation and proliferation effects.  

PubMed

This report examines the transcriptional roles and DNA binding properties of the three major organosulfur compounds (OSCs) from garlic, diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS). We found DADS and DATS, but not DAS, could be activated by the versatile epoxide-forming oxidant dimethyldioxirane (DMDO) and could strongly inhibit nuclear RNA synthesis in vitro. We also found that when incubated together with [3H]-labeled 17beta-estradiol (E(2)) for activation by DMDO, DADS and DATS, but not DAS, were able to prevent the binding of [3H]E(2) to DNA. This preventive effect of DADS and DATS was confirmed when liver microsomes were used, and further verified by 32P post-labeling analysis. Additionally, we discovered that the DMDO treated DADS and DATS, but not DAS, were able to directly inhibit the enzyme RNA polymerase per se. These novel findings provide new insights into the potential mechanisms of the preventive effects of OSCs on tumor initiation and promotion. PMID:14585324

Yu, Fu Li; Bender, Wanda; Fang, Qingming; Ludeke, Anna; Welch, Brianna

2003-01-01

302

Estrogen receptor agonists and immune system in ovariectomized mice.  

PubMed

Several data implicate the immune system in bone lost after estrogen deficiency, however, some of the effects on the immune system of estrogen deficiency or of estrogen receptor (ER) modulation are not well established. In this study, the effect of ER agonists on the immune system in ovariectomized mice is analyzed. Mice were ovariectomized and were administered 17beta-estradiol (E2), raloxifene (RAL) or genistein (GEN). The effect of a 4-week treatment on bone turnover and on several parameters that reflect the status of the immune system was studied. Results show that ovariectomy provoked both uterine atrophy and thymic hypertrophy. Although RAL corrected thymic hypertrophy, only E2 corrected both. Ovariectomized mice showed increased levels of serum calcium and cathepsin K gene expression and decreased levels of serum alkaline phosphatase (ALP) activity, which suggests that there is a persistent alteration in bone metabolism. Moreover, ovariectomy increased B-cells and CD25+ cells, and decreased the percentages of T-cells and Cbfa1 gene expression in bone marrow (BM). All ER agonists corrected, although to different degrees, changes induced by the ovariectomy. Furthermore, results showed that it is essential to adjust ER agonist doses to avoid immunosuppression, since all ER agonists decreased BM T-cell levels. PMID:17166402

García-Pérez, M A; Del Val, R; Noguera, I; Hermenegildo, C; Pineda, B; Martinez-Romero, A; Cano, A

2006-01-01

303

Sex steroids levels in the plasma and testis during the reproductive cycle of lizard Podarcis s. sicula Raf.  

PubMed

Progesterone (P), 17-OH-progesterone (17-OH-P), androstenedione (A), dehydroepiandrosterone (DHEA), testosterone (T), 5 alpha-dihydrotestosterone (5 alpha-DHT), and 17 beta-estradiol (E2) were measured by RIA in plasma and testes of 114 males of the oviparous lizard Podarcis s. sicula raf, a species that displays annual hibernating cycles. Hormones were determined each month from January until December, except for August. Testosterone peaked at 174.8 ng/ml of plasma after emergence (March), while 5 alpha-DHT and A peaked in April. Plasma DHEA increased during hibernation. During the refractory period there were progressive increases in P and E2 plasma levels. The testicular peak of T, in March, coincided with that observed in plasma. The striking increases in testicular T and A in early July occurred at a time when plasma androgen concentrations were low. 5 alpha-DHT increased in April when spermatogenesis with spermiation occurred and then decreased alongside a second peak of T. There is an apparent separation of plasma and testicular androgen concentrations during the reproductive cycle. PMID:1532946

Andò, S; Ciarcia, G; Panno, M L; Imbrogno, E; Tarantino, G; Buffone, M; Beraldi, E; Angelini, F; Botte, V

1992-01-01

304

CO-induction of rat intestinal cancers with 7,12-dimethylbenz(a)anthracene and medroxyprogesterone acetate  

SciTech Connect

Medroxy progesterone acetate (P) is a progestin used for treatment of sex hormone-dependent human cancers. In a study of its action, 7,12-dimethyl-benz(a)anthracene (DMBA) was given, i.g., to 50-52 day old intact or gonadectomized Sprague-Dawley rats of both sexes. Groups were given 0, 5, 25 or 100 mg of P +/- 2, .5, .1, .01 or .001 mg of 17 beta estradiol (E2), s.c., each week for 12-36 weeks. Those given P often developed, independent of sex or gonadectomy, multiple intestinal adenomas and carcinomas, especially in the jejunum. At doses of P tumor incidence was as follows: 0 mg, 2/63; 5 mg, 18/96; 25 mg, 35/57; 100 mg, 72/155. Combinations of P with doses of E2 at 2, .5 or .1 mg reduced tumor incidence 65%. At 25 or 100 mg doses of P, DMBA induction of mammary tumors was inhibited, while atrophy of ovaries and adrenal cortex was impressive. Hence, this is the only progestin, which favors DMBA induction of tumors of the rat intestine, while extinguishing mammary tumors. This matter may bear on presence of hormone receptors in human colo-rectal cancers.

Hass, G.; Galt, R.; Coogan, P.; Friese, J.

1986-03-01

305

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

306

The Sulfatase Pathway for Estrogen Formation: Targets for the Treatment and Diagnosis of Hormone-Associated Tumors  

PubMed Central

The extragonadal synthesis of biological active steroid hormones from their inactive precursors in target tissues is named “intracrinology.” Of particular importance for the progression of estrogen-dependent cancers is the in situ formation of the biological most active estrogen, 17beta-estradiol (E2). In cancer cells, conversion of inactive steroid hormone precursors to E2 is accomplished from inactive, sulfated estrogens in the “sulfatase pathway” and from androgens in the “aromatase pathway.” Here, we provide an overview about expression and function of enzymes of the “sulfatase pathway,” particularly steroid sulfatase (STS) that activates estrogens and estrogen sulfotransferase (SULT1E1) that converts active estrone (E1) and other estrogens to their inactive sulfates. High expression of STS and low expression of SULT1E1 will increase levels of active estrogens in malignant tumor cells leading to the stimulation of cell proliferation and cancer progression. Therefore, blocking the “sulfatase pathway” by STS inhibitors may offer an attractive strategy to reduce levels of active estrogens. STS inhibitors either applied in combination with aromatase inhibitors or as novel, dual aromatase-steroid sulfatase inhibiting drugs are currently under investigation. Furthermore, STS inhibitors are also suitable as enzyme–based cancer imaging agents applied in the biomedical imaging technique positron emission tomography (PET) for cancer diagnosis. PMID:23476785

Secky, Lena; Svoboda, Martin; Klameth, Lukas; Bajna, Erika; Hamilton, Gerhard; Zeillinger, Robert; Jager, Walter; Thalhammer, Theresia

2013-01-01

307

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

308

E2F1 expression is deregulated and plays an oncogenic role in sporadic Burkitt's lymphoma  

PubMed Central

Current treatments of sBL are associated with severe toxicities. A better understanding of sBL formation would facilitate development of less toxic therapies. The etiology of sporadic Burkitt’s lymphoma (sBL) remains however largely unknown, being C-MYC up-regulation the only lesion known to occur in all sBL cases. Several studies examining the role of C-MYC in the pathogenesis of BL have concluded that C-MYC translocation is not the only critical event and that additional unidentified factors are expected to be involved in the formation of this tumor. We herein report that a gene distinct from C-MYC, E2F1, is involved in the formation of all or most sBL tumors. We found that E2F1 is highly expressed in Burkitt’s lymphoma cell lines and sBL lymphoma specimens. Our data indicate that its elevated expression is not merely the consequence of the presence of more cycling cells in this tumor relative to other cell lines or to other neoplasias. In fact, we show that reduction of its expression in sBL cells inhibits tumor formation and decreases their proliferation rate. We also provide data suggesting that E2F1 collaborates with C-MYC in sBL formation. E2F1 expression down-regulation did not affect, however, proliferation of human primary diploid fibroblasts. Since E2F1 is not needed for cell proliferation of normal cells, our results reveal E2F1 as a promising therapeutic target for sBL. PMID:19406837

Molina-Privado, Irene; Rodriguez-Martinez, Maria; Rebollo, Patricia; Martin-Perez, Daniel; Artiga, Maria-Jesus; Menarguez, Javier; Flemington, Erik K.; Piris, Miguel A.; Campanero, Miguel R.

2009-01-01

309

The challenges of classical swine fever control: modified live and E2 subunit vaccines.  

PubMed

Classical swine fever (CSF) is an economically important, highly contagious disease of swine worldwide. CSF is caused by classical swine fever virus (CSFV), and domestic pigs and wild boars are its only natural hosts. The two main strategies used to control CSF epidemic are systematic prophylactic vaccination and a non-vaccination stamping-out policy. This review compares the protective efficacy of the routinely used modified live vaccine (MLV) and E2 subunit vaccines and summarizes the factors that influence the efficacy of the vaccines and the challenges that both vaccines face to CSF control. Although MLV provide earlier and more complete protection than E2 subunit vaccines, it has the drawback of not allowing differentiation between infected and vaccinated animals (DIVA). The marker vaccine of E2 protein with companion discriminatory test to detect antibodies against E(rns) allows DIVA and is a promising strategy for future control and eradication of CSF. Maternal derived antibody (MDA) is the critical factor in impairing the efficacy of both MLV and E2 subunit vaccines, so the well-designed vaccination programs of sows and piglets should be considered together. Because of the antigen variation among various genotypes of CSFV, antibodies raised by either MLV or subunit vaccine neutralize genotypically homologous strains better than heterologous ones. However, although this is not a major concern for MLV as the induced immune responses can protect pigs against the challenge of various genotypes of CSFVs, it is critical for E2 subunit vaccines. It is thus necessary to evaluate whether the E2 subunit vaccine can completely protect against the current prevalent strains in the field. An ideal new generation of vaccine should be able to maintain the high protective efficiency of MLV and overcome the problem of antigenic variations while allowing for DIVA. PMID:24211665

Huang, Yu-Liang; Deng, Ming-Chung; Wang, Fun-In; Huang, Chin-Cheng; Chang, Chia-Yi

2014-01-22

310

The E2 contribution to the 8B -> p + 7Be Coulomb dissociation cross section  

E-print Network

We have calculated the E1 and E2 contributions to the low-energy B-8 + Pb-208 -> p + Be-7 + Pb-208 Coulomb dissociation cross sections using the kinematics of a recent experiment at RIKEN. Using a potential model description of the Be-7 (p,gamma) B-8 reaction, we find that the E2 contributions cannot a priori be ignored in the analysis of the data. Its inclusion reduces the extracted Be-7 (p,gamma) B-8 S-factor at solar energies by about 25%.

K. Langanke; T. D. Shoppa

1994-02-02

311

Measurement of E2 Transitions in the Coulomb Dissociation of 8B  

E-print Network

In an effort to understand the implications of Coulomb dissociation experiments for the determination of the 7Be(p,gamma)8B reaction rate, longitudinal momentum distributions of 7Be fragments produced in the Coulomb dissociation of 44 and 81 MeV/nucleon 8B beams on a Pb target were measured. These distributions are characterized by asymmetries interpreted as the result of interference between E1 and E2 transition amplitudes in the Coulomb breakup. At the lower beam energy, both the asymmetries and the measured cross sections are well reproduced by perturbation theory calculations, allowing a determination of the E2 strength.

B. Davids; D. W. Anthony; Sam M. Austin; D. Bazin; B. Blank; J. A. Caggiano; M. Chartier; H. Esbensen; P. Hui; C. F. Powell; H. Scheit; B. M. Sherrill; M. Steiner; P. Thirolf

1998-03-26

312

E2 Instanton Effects and Higgs Physics In Intersecting Brane Models  

E-print Network

String instanton effects in Higgs physics are discussed through a type IIA model based on T^{6}/(Z^{2}\\times Z^{'2}) orentifold compactifaction. By inclusion of rigid E2-branes, the model exhibits a MSSM-like spectrum, as well as extra mu and quartic Higgs couplings. These extra couplings are induced via E2 instantons non-perturbatively. Setting the string scale at 10^{18} GeV, one gets interesting TeV Higgs physics. In particlular, the tree-level Higgs mass can be uplifted substantially.

Mingxing Luo; Sibo Zheng

2008-04-21

313

Cell transformation mediated by homodimeric E2A-HLF transcription factors.  

PubMed Central

The E2A-HLF fusion gene, created by the t(17;19)(q22;p13) chromosomal translocation in pro-B lymphocytes, encodes an oncogenic protein in which the E2A trans-activation domain is linked to the DNA-binding and protein dimerization domain of hepatic leukemia factor (HLF), a member of the proline- and acidic amino acid-rich (PAR) subfamily of bZIP transcription factors. This fusion product binds to its DNA recognition site not only as a homodimer but also as a heterodimer with HLF and two other members of the PAR bZIP subfamily, thyrotroph embryonic factor (TEF) and albumin promoter D-box binding protein (DBP). Thus, E2A-HLF could transform cells by direct regulation of downstream target genes, acting through homodimeric or heterodimeric complexes, or by sequestering normal PAR proteins into nonfunctional heterocomplexes (dominant-negative interference). To distinguish among these models, we constructed mutant E2A-HLF proteins in which the leucine zipper domain of HLF was extended by one helical turn or altered in critical charged amino acids, enabling the chimera to bind to DNA as a homodimer but not as a heterodimer with HLF or other PAR proteins. When introduced into NIH 3T3 cells in a zinc-inducible vector, each of these mutants induced anchorage-independent growth as efficiently as unaltered E2A-HLF, indicating that the chimeric oncoprotein can transform cells in its homodimeric form. Transformation also depended on an intact E2A activator region, providing further support for a gain-of-function contribution to oncogenesis rather than one based on a dominant-interfering or dominant-negative mechanism. Thus, the tumorigenic effects of E2A-HLF and its mutant forms in NIH 3T3 cells favor a straightforward model in which E2A-HLF homodimers bind directly to promoter/enhancer elements of downstream target genes and alter their patterns of expression in early B-cell progenitors. PMID:9032268

Inukai, T; Inaba, T; Yoshihara, T; Look, A T

1997-01-01

314

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

315

pSa Causes Oncogenic Suppression of Agrobacterium by Inhibiting VirE2 Protein Export  

PubMed Central

When coresident with the Ti (tumor-inducing) plasmid, the 21-kDa product of the osa gene of the plasmid pSa can suppress crown gall tumorigenesis incited by Agrobacterium tumefaciens. Neither T-DNA processing nor vir (virulence) gene induction is affected by the presence of osa in the bacterium. We used Arabidopsis thaliana root segments and tobacco leaf discs to demonstrate that Osa inhibits A. tumefaciens from transforming these plants to the stable phenotypes of tumorigenesis, kanamycin resistance, and stable ?-glucuronidase (GUS) expression. When A. tumefaciens contained osa, the lack of expression of transient GUS activity in infected plant tissues, as well as the lack of systemic viral symptoms following agroinfection of Nicotiana benthamiana by tomato mottle virus, suggested that oncogenic suppression by Osa occurs before T-DNA enters the plant nucleus. The extracellular complementation of an A. tumefaciens virE2 mutant (the T-DNA donor strain) by an A. tumefaciens strain lacking T-DNA but containing a wild-type virE2 gene (the VirE2 donor strain) was blocked when osa was present in the VirE2 donor strain, but not when osa was present in the T-DNA donor strain. These data indicate that osa inhibits VirE2 protein, but not T-DNA export from A. tumefaciens. These data further suggest that VirE2 protein and T-DNA are separately exported from the bacterium. The successful infection of Datura stramonium plants and leaf discs of transgenic tobacco plants expressing VirE2 protein by an A. tumefaciens virE2 mutant carrying osa confirmed that oncogenic suppression by osa does not occur by blocking T-DNA transfer. Overexpression of virB9, virB10, and virB11 in A. tumefaciens did not overcome oncogenic suppression by osa. The finding that the expression of the osa gene by itself, rather than the formation of a conjugal intermediate with pSa, blocks transformation suggests that the mechanism of oncogenic suppression by osa may differ from that of the IncQ plasmid RSF1010. PMID:9864329

Lee, Lan-Ying; Gelvin, Stanton B.; Kado, Clarence I.

1999-01-01

316

Ontogeny of rapid estrogen-mediated extracellular signal-regulated kinase signaling in the rat cerebellar cortex: potent nongenomic agonist and endocrine disrupting activity of the xenoestrogen bisphenol A.  

PubMed

In addition to regulating estrogen receptor-dependent gene expression, 17beta-estradiol (E(2)) can directly influence intracellular signaling. In primary cultured cerebellar neurons, E(2) was previously shown to regulate growth and oncotic cell death via rapid stimulation of ERK1/2 signaling. Here we show that ERK1/2 signaling in the cerebellum of neonatal and mature rats was rapidly responsive to E(2) and during development to the environmental estrogen bisphenol A (BPA). In vivo dose-response analysis for each estrogenic compound was performed by brief (6-min) intracerebellar injection, followed by rapid fixation and phosphorylation-state-specific immunohistochemistry to quantitatively characterize changes in activated ERK1/2 (pERK) immunopositive cell numbers. Beginning on postnatal d 8, E(2) significantly influenced the number of pERK-positive cells in a cell-specific manner that was dependent on concentration and age but not sex. In cerebellar granule cells on postnatal d 10, E(2) or BPA increased pERK-positive cell numbers at low doses (10(-12) to 10(-10) M) and at higher (10(-7) to 10(-6) M) concentrations. Intermediate concentrations of either estrogenic compound did not modify basal ERK signaling. Rapid E(2)-induced increases in pERK immunoreactivity were specific to the ERK1/2 pathway as demonstrated by coinjection of the mitogen-activated, ERK-activating kinase (MEK)1/2 inhibitor U0126. Coadministration of BPA (10(-12) to 10(-10) M) with 10(-10) M E(2) dose-dependently inhibited rapid E(2)-induced ERK1/2 activation in developing cerebellar neurons. The ability of BPA to act as a highly potent E(2) mimetic and to also disrupt the rapid actions of E(2) at very low concentrations during cerebellar development highlights the potential low-dose impact of xenoestrogens on the developing brain. PMID:16123166

Zsarnovszky, Attila; Le, Hoa H; Wang, Hong-Sheng; Belcher, Scott M

2005-12-01

317

E2F1 plays a direct role in Rb stabilization and p53-independent tumor suppression  

PubMed Central

To better understand the role of E2F1 in tumor formation, we analyzed spontaneous tumorigenesis in p53?/?E2F1+/+ and p53?/?E2F1?/? mice. We show that the combined loss of p53 and E2F1 leads to an increased incidence of sarcomas and carcinomas compared to the loss of p53 alone. E2F1-deficient tumors show wide chromosomal variation, indicative of genomic instability. Consistent with this, p53?/?E2F1?/? primary fibroblasts have a reduced capacity to maintain genomic stability when exposed to S-phase inhibitors or genotoxic drugs. A major mechanism of E2F1’s contribution to genomic integrity lies in mediating stabilization and engagement of the Rb protein. PMID:18583939

Palacios, Gustavo; Talos, Flaminia; Nemajerova, Alice; Moll, Ute M.; Petrenko, Oleksi

2013-01-01

318

Structure of the Human FANCL RING-Ube2T Complex Reveals Determinants of Cognate E3-E2 Selection  

PubMed Central

Summary 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

2014-01-01

319

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

320

Mechanisms of Human Papillomavirus E2-Mediated Repression of Viral Oncogene Expression and Cervical Cancer Cell Growth Inhibition  

PubMed Central

The papillomavirus E2 gene product plays a pivotal role in viral replication. E2 has multiple functions, including (i) transcriptional activation and repression of viral promoters and (ii) the enhancement of viral DNA replication. It was previously reported that E2 suppressed the growth of papillomavirus-positive cervical carcinoma cell lines. In the present study, we investigated the mechanisms of E2 growth inhibition. We found that the transcriptional activation function of E2 is required for inhibition of the growth of HeLa cells as well as for transcriptional repression of the viral E6/E7 promoter. It had been previously postulated that transcriptional repression of the E6/E7 promoter results from E2 binding its cognate sites proximal to the E6/E7 promoter and displacing other cellular transcriptional factors. In this study, we report a requirement for the transcription activation function for the binding of E2 to transcriptionally active templates. PMID:10729150

Nishimura, Akiko; Ono, Takeshi; Ishimoto, Akinori; Dowhanick, Jennifer J.; Frizzell, Margaret A.; Howley, Peter M.; Sakai, Hiroyuki

2000-01-01

321

Localization of HPV-18 E2 at Mitochondrial Membranes Induces ROS Release and Modulates Host Cell Metabolism  

PubMed Central

Papillomavirus E2 proteins are predominantly retained in the nuclei of infected cells, but oncogenic (high-risk) HPV-18 and 16 E2 can shuttle between the host nucleus and cytoplasm. We show here that cytoplasmic HPV-18 E2 localizes to mitochondrial membranes, and independent mass spectrometry analyses of the E2 interactome revealed association to the inner mitochondrial membrane including components of the respiratory chain. Mitochondrial E2 association modifies the cristae morphology when analyzed by electron microscopy and increases production of mitochondrial ROS. This ROS release does not induce apoptosis, but instead correlates with stabilization of HIF-1? and increased glycolysis. These mitochondrial functions are not shared by the non-oncogenic (low-risk) HPV-6 E2 protein, suggesting that modification of cellular metabolism by high-risk HPV E2 proteins could play a role in carcinogenesis by inducing the Warburg effect. PMID:24086592

Gunaratne, Jayantha; Quek, Ling Shih; Nei, Wenlong; Thierry, Francoise; Bellanger, Sophie

2013-01-01

322

Triaxial rotor model description of E2 properties in {sup 186,188,190,192}Os  

SciTech Connect

The triaxial rotor model with independent inertia and electric quadrupole tensors is applied to the description of the extensive set of E2 matrix elements available for {sup 186,188,190,192}Os. Most large and medium transition E2 matrix elements can be reproduced to within {approx}10%, and most diagonal elements to within {approx}30%. Most small transition matrix elements can be reproduced to within {approx}30%, and they support the interference effect exhibited by the model between the inertia and E2 tensors: this is a new feature of quantum rotor models. The diagonal E2 matrix elements at higher spins in the K=2 band are extremely sensitive to admixtures of higher K values: the low experimental values in {sup 190,192}Os indicate significant admixtures of K=4 components. Attention is given to the K{sup {pi}}=4{sup +} bands in these nuclei and the controversial issue of whether they are of quadrupole or hexadecapole nature.

Allmond, J. M.; Zaballa, R.; Oros-Peusquens, A. M.; Kulp, W. D.; Wood, J. L. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States)

2008-07-15

323

Precision calculation for e+ e- -> 2f: the KK MC project  

E-print Network

We present the current status of the coherent exclusive (CEEX) realization of the YFS theory for the processes in e+ e- -> 2f via the KK MC. We give a brief summary of the CEEX theory in comparison to the older (EEX) exclusive exponentiation theory and illustrate recent theoretical results relevant to the LEP2 and LC physics programs.

B. F. L. Ward; S. Jadach; Z. Was

2002-11-09

324

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

325

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

E-print Network

." -- President Barack Obama,April 15,2010 The space age began as a race for security and prestige between two J U N E 2 8 , 2 010 NATIONAL SPACE POLICY of the UNITED STATES of AMERICA #12 by the thought of exploring the mysteries of outer space. Through such exploration,man hopes to broaden his

Rathbun, Julie A.

326

Production of prostaglandin E2 induced by histamine by cloned rheumatoid synovial cells  

Microsoft Academic Search

Production of prostaglandin E2, with or without histamine stimulation, by three different types of cloned rheumatoid synovial cells (macrophage like, dendritic, and fibroblast like) was evaluated. The ability of these cloned cells to respond to histamine on a cell to cell basis was as follows: macrophage like cells responded most strongly, followed by dendritic cells, followed by fibroblast like cells.

M Sasano; M Goto; K Nishioka

1990-01-01

327

Merging of E2 and E1cb Reaction Mechanisms: A Combined Theoretical and Experimental Study  

Microsoft Academic Search

By combining the results of kinetic measurements with DFT calculations we provide a clear-cut evidence of the merging between the E2 and E1cb reaction mechanisms for a large series of leaving groups. Our results solve a long-debated issue in chemical reactivity with profound implications both

Edoardo Mosconi; Filippo De Angelis; Leonardo Belpassi; Francesco Tarantelli; Sergio Alunni

2009-01-01

328

Inhibitions of Histamine Release and Prostaglandin E2 Synthesis by Mangosteen, a Thai Medicinal Plant  

Microsoft Academic Search

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 un- dertaken to examine the effects of mangosteen extracts (100% ethanol, 70% ethanol, 40% ethanol and water) on histamine release and prostaglandin E2 synthesis. We

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

2002-01-01

329

Production and characterization of mouse monoclonal antibodies reactive to Chikungunya envelope E2 glycoprotein.  

PubMed

Chikungunya fever is an arbovirosis of major impact in public health in Asia and Africa. Chikungunya (CHIK) virus is member of the genus Alphavirus and belongs to the Semliki Forest (SF) antigenic complex. We describe for the first time a panel of monoclonal antibodies (MAbs) reactive to CHIK envelope E2 glycoprotein. For the screening of E2-specific MAbs, we expressed a recombinant soluble CHIK E2 protein in Drosophila S2 cells. Analyzed by immunological methods, MAbs 3C3, 3E4, and 8A4 were selected on the basis of their reactivity. Their epitopes are located to the outer surface of CHIK virion. These MAbs have no cross reactivity with related members of SF antigenic complex with the notable exception of Igbo-Ora virus. Anti-CHIK E2 MAbs 3C3, 3E4, and 8A4 should be helpful for studying the biology of CHIK virus and pathogenesis of disease. The combination of 8A4 and 3E4 is suitable for developing a specific antigen-capture ELISA. PMID:17949772

Bréhin, Anne-Claire; Rubrecht, Laetitia; Navarro-Sanchez, Martha Erika; Maréchal, Valérie; Frenkiel, Marie-Pascale; Lapalud, Priscilla; Laune, Daniel; Sall, Amadou Alpha; Desprès, Philippe

2008-02-01

330

Orbital M1 versus E2 strength in deformed nuclei: A new energy weighted sum rule  

E-print Network

Within the unified model of Bohr and Mottelson we derive the following linear energy weighted sum rule for low energy orbital 1$^+$ excitations in even-even deformed nuclei $$S_{\\rm LE}^{\\rm lew} (M_1^{\\rm orb}) \\cong (6/5) \\epsilon (B(E2; 0^+_1 \\rightarrow 2_1^+ K=0)/Z e^2^2) \\mu^2_N$$ with B(E2) the E2 strength for the transition from the ground state to the first excited state in the ground state rotational band, $$ the charge r.m.s. radius squared and $\\epsilon$ the binding energy per nucleon in the nuclear ground state. It is shown that this energy weighted sum rule is in good agreement with available experimental data. The sum rule is derived using a simple ansatz for the intrinsic ground state wave function that predicts also high energy 1$^+$ strength at 2$\\hbar \\omega$ carrying 50\\% of the total $m_1$ moment of the orbital M1 operator.

E. Moya de Guerra; L. Zamick

1993-03-16

331

17?-Estradiol is critical for the preovulatory induction of prostaglandin E(2) synthesis in mice.  

PubMed

Aromatase-deficient (ArKO) mice are totally anovulatory due to insufficient estrogen production. However, sequential administrations of high doses of 17?-estradiol (E2) and gonadotropins were found to induce ovulation in these mice. Here, we examined how the ovulatory stimulation for ArKO mice alters the expressions of genes related to prostaglandin (PG) E(2) metabolism and ovarian contents of PGE(2), as PGE(2) is one of the critical mediators of ovulatory induction. The ovulatory stimulation significantly increased mRNA expressions of prostaglandin-endoperoxide synthase 2, PGE(2) receptor type 4 and sulfotransferase family 1E, member 1, in preovulatory ArKO ovaries. In contrast, it suppressed the mRNA expression of 15-hydroxyprostaglandin dehydrogenase. Furthermore, significant elevation in the PGE(2) contents was detected in the preovulatory ovaries of ArKO mice after stimulation with E2 plus ovulatory doses of gonadotropins. Thus, these analyses demonstrate a requirement of E2 for the preovulatory enhancement of PGE(2) synthesis, leading to future success in ovulation. PMID:22713853

Toda, Katsumi; Ono, Masafumi; Yuhki, Koh-ichi; Ushikubi, Fumitaka; Saibara, Toshiji

2012-10-15

332

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

333

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

334

Survivin repression by p53, Rb, and E2F2 in normal human melanocytes  

PubMed Central

The inhibitor of apoptosis (IAP) protein Survivin is a dual mediator of apoptosis resistance and cell cycle progression, and is highly expressed in cancer. We have previously shown that Survivin is upregulated in melanoma compared to normal melanocytes, is required for melanoma cell viability, and that melanocyte expression of Survivin predisposes mice to UV-induced melanoma and metastasis. The mechanism(s) of Survivin upregulation in the course of melanocyte transformation, and its repression in normal melanocytes, however, has not been clearly defined. We show here that p53 and Rb, at basal levels and in the absence of any activating stimuli, are both required to repress survivin transcription in normal human melanocytes. Survivin repression in melanocytes does not involve alterations in protein stability or promoter methylation. p53 and Rb (via E2Fs) regulate Survivin expression by direct binding to the survivin promoter; p53 also affects Survivin expression by activating p21. We demonstrate a novel role for E2F2 in the negative regulation of Survivin expression. In addition, we identify a novel E2F-binding site in the survivin promoter and show that mutation of either the p53- or E2F-binding sites is sufficient to increase promoter activity. These studies suggest that compromise of either p53 or Rb pathways during melanocyte transformation leads to upregulation of Survivin expression in melanoma. PMID:17916908

Raj, Deepak; Liu, Tong; Samadashwily, George; Li, Fengzhi; Grossman, Douglas

2008-01-01

335

pRb-Independent Growth Arrest and Transcriptional Regulation of E2F Target Genes1  

PubMed Central

Abstract The retinoblastoma tumor suppressor (pRb) has traditionally been studied as a negative regulator of cell cycle progression through its interactions with the E2F family of transcription factors. Utilizing prostate epithelial cell lines established from Rb+/+ and Rb-/- prostate tissues, we previously demonstrated that Rb-/- epithelial cells were not transformed and retained the ability to differentiate in vivo despite the lack of pRb. To further study the effects of pRb loss in an epithelial cell population, we utilized oligonucleotide microarrays to identify any pRb-dependent transcriptional regulation during serum depletion-induced growth arrest. These studies identified 120 unique transcripts regulated by growth arrest in Rb+/+ cells. In these wild-type cells, the majority (80%) of altered transcripts were downregulated, including 40 previously identified E2F target genes. Although the transcriptional repression of E2F target genes is characteristic of pRb pocket protein family activity, further analysis revealed that, compared to Rb+/+ cells, Rb-/- cells exhibited a nearly identical response for all transcripts including those of E2F target genes. These findings demonstrate that pRb is not strictly required for the vast majority of transcriptional alterations associated with growth arrest. PMID:15802019

McCabe, Michael T; Azih, Odinaka J; Day, Mark L

2005-01-01

336

E2E blocking probability of IPTV and P2PTV? , Fernando Kuipers1  

E-print Network

E2E blocking probability of IPTV and P2PTV? Yue Lu1 , Fernando Kuipers1 , Milena Janic2 and Piet for IPTV or P2PTV based on the Quality of Experience (QoE). In this paper, we investigate one important Qo different ways: either utilizing a mechanism on the IP layer (IPTV) or on the application layer (P2PTV

Van Mieghem, Piet

337

The E2 domains of APP and APLP1 share a conserved mode of dimerization  

PubMed Central

Amyloid precursor protein (APP) is genetically linked to Alzheimer’s disease. APP is a type I membrane protein, and its oligomeric structure is potentially important because this property may play a role in its function, or affect the processing of the precursor by the secretases to generate amyloid ?-peptide. Several independent studies have shown that APP can form dimers in the cell, but how it dimerizes remains controversial. At least three regions of the precursor, including a centrally located and conserved domain called E2, have been proposed to contribute to dimerization. Here we report two new crystal structures of E2, one from APP, and the other from APLP1, a mammalian APP homolog. Comparison with an earlier APP structure, which was solved in a different space group, shows that the E2 domains share a conserved and anti-parallel mode of dimerization. Biophysical measurements in solution show that heparin binding induces E2 dimerization. The 2.1Å resolution electron density map also reveals phosphate ions that are bound to the protein surface. Mutational analysis shows that protein residues interacting with the phosphate ions are also involved in heparin binding. The locations of two of these residues, Arg-369 and His-433, at the dimeric interface suggest a mechanism for heparin-induced protein dimerization. PMID:21574595

Lee, Sangwon; Xue, Yi; Hu, Jian; Wang, Yongcheng; Liu, Xuying; Demeler, Borries; Ha, Ya

2011-01-01

338

The E2A gene product contains two separable and functionally distinct transcription activation domains.  

PubMed Central

The E2A gene encodes transcription factors of the helix-loop-helix (HLH) family which are implicated in cell-specific transcriptional control in several cell lineages, including pancreatic beta cells. In the present work, we show by deletion mapping of both the E2A protein itself and the Gal4-E2A fusion protein that the protein contains at least two distinct activation domains. One domain (located between amino acids 1 and 153) functions efficiently in a variety of mammalian cell lines. The second domain (located between amino acids 369 and 485) functions preferentially in pancreatic beta cell lines. The latter domain shows a pattern of heptad repeats of leucine residues characteristics of "leucine zipper" transcription factors; site-directed mutagenesis of leucines within this repeat led to substantial reductions in activity. The selective properties of this activation domain may contribute to cell-specific transcription directed by the E2A gene. Images Fig. 1 Fig. 2 Fig. 3 PMID:8367464

Aronheim, A; Shiran, R; Rosen, A; Walker, M D

1993-01-01

339

Stages of Change - Continuous Measure (URICA-E2): psychometrics of a Norwegian version  

PubMed Central

Title Stages of Change – Continuous Measure (URICA-E2): psychometrics of a Norwegian version. Aim This paper is a report of research to translate the English version of the Stages of Change continuous measure questionnaire (URICA-E2) into Norwegian and to test the validity of the questionnaire and its usefulness in predicting behavioural change. Background While the psychometric properties of the Stages of Change categorical measure have been tested extensively, evaluation of the psychometric properties of the continuous questionnaire has not been described elsewhere in the literature. Method Cross-sectional data were collected with a convenience sample of 198 undergraduate nursing students in 2005 and 2006. The English version of URICA-E2 was translated into Norwegian according to standardized procedures. Findings Principal components analysis clearly confirmed five of the dimensions of readiness to change (Precontemplation Non-Believers, Precontemplation Believers, Contemplation, Preparation and Maintenance), while the sixth dimension, Action, showed the lowest Eigenvalue (0·93). Findings from the cluster analysis indicate distinct profiles among the respondents in terms of readiness to change their exercise behaviour. Conclusion The URICA-E2 was for the most part replicated from Reed’s original work. The result of the cluster analysis of the items associated with the factor ‘Action’ suggests that these do not adequately measure the factor. PMID:19032513

Lerdal, Anners; Moe, Britt; Digre, Elin; Harding, Thomas; Kristensen, Frode; Grov, Ellen K; Bakken, Linda N; Eklund, Marthe L; Ruud, Ireen; Rossi, Joseph S

2009-01-01

340

Exposure to traffic pollutants and effects on 17-?-estradiol (E2) in female workers  

Microsoft Academic Search

Objective: The aim of the study is to evaluate whether the occupational exposure to urban pollutants including endocrine disruptors (EDs) could cause alterations in plasma 17-?-estradiol (E2) levels and related diseases (adverse pregnancy outcome and mental health disorders) in female traffic police compared to a control group. Methods: After excluding the subjects with the principal confounding factors, traffic police and

Gianfranco Tomei; Manuela Ciarrocca; Bruna Rita Fortunato; Assunta Capozzella; Maria Valeria Rosati; Daniela Cerratti; Enrico Tomao; Vincenza Anzelmo; Carlo Monti; Francesco Tomei

2006-01-01

341

Hecke Operations and the Adams E2Term Based on Elliptic Cohomology  

Microsoft Academic Search

Hecke operators are used to investigate part of the E2-term of the Adams spectral sequence based on elliptic homology. The main result is a derivation of Ext1 which combines use of classical Hecke operators and p-adic Hecke operators due to Serre.

Andrew Baker

342

Sensitivity of lymphocytes to prostaglandin E2 increases in subjects over age 70.  

PubMed Central

We examined the sensitivity of lymphocytes from different age groups to inhibition by prostaglandin E2. Phytohemagglutinin-stimulated cultures of peripheral blood mononuclear cells from 12 healthy subjects over the age of 70 were much more sensitive to inhibition by exogenously added prostaglandin E2 than were cells from 17 young controls (ID50 congruent to 10 nM for the subjects over 70 vs. greater than 3 micronM for the young controls). The more senstivie lymphocytes from a subject over 70 were to prostaglandin E2, the lower was his or her response to phytohemagglutinin (r = 0.75, P less than 0.01). The mean responses to phytohemagglutinin of the peripheral blood mononuclear cells from the subjects over 70 were significantly depressed compared to the young controls. Addition of indomethacin, a prostaglandin synthetase inhibitor, to the cultures resulted in an increase in [3H]thymidine incorporation of 140 +/- 16% in the cells of the subjects over 70 vs. a 36 +/- 3% increase in the young controls (mean +/- SEM, P less than 0.001). The mean phytohemagglutinin response of the subjects over 70 was 40% of the control response without indomethacin. With addition of indomethacin the response of subjects over 70 rose to 72% of control. Thus, increased sinsitivity to prostaglandin E2 appears to be responsible in part for the depressed mitogen response of peripheral blood mononuclear cells from healthy subjects over 70. PMID:457862

Goodwin, J S; Messner, R P

1979-01-01

343

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. Human papillomaviruses (HPVs) can be broadly divided in two groups; low- risk HPV subtypes cause benign- and low-risk HPV subtypes. INTRODUCTION Human papillomaviruses (HPVs) are icosahedral DNA tumour viruses

Gaston, Kevin

344

c-Jun inhibits NF-E2 transcriptional activity in association with p18/maf in Friend erythroleukemia cells.  

PubMed

We have reported previously that antisense c-jun overcomes a block of Friend erythroleukemia cells to differentiation suggesting that the factor c-Jun may be an important negative regulator of erythroid differentiation. The recently described erythroid transcription factor NF-E2 plays an important role in the regulation of the transcription of globin genes and recognizes a sequence containing an AP-1 site. NF-E2 is a complex of two bZip proteins, p45 and p18/Maf. In order to determine whether c-Jun can interact with NF-E2/AP-1 sites to regulate transcriptional activation from them, we have compared the activity of AP-1 and NF-E2 in transient transcriptional assays, in erythroid and nonerythroid cells in the presence of c-jun sense and antisense expression vectors. In non-erythroid cells, c-Jun activates and NF-E2p18 inhibits both AP-1 and NF-E2 activities, suggesting that NF-E2/AP-1 sites function as AP-1 binding sites in these cells. In contrast, NF-E2p18 is a positive regulator of NF-E2 activity in erythroid cells. c-Jun alone is also a positive regulator of NF-E2 activity in erythroid cells but in association with NF-E2p18 inhibits this activity. Moreover antisense c-jun increases endogenous NF-E2 activity in erythroid cells. These results suggest that c-Jun could act as a repressor of NF-E2 transcriptional activity by forming inactive c-Jun/NF-E2p18 heterocomplexes which interfer with the transcription of globin genes in Friend erythroleukemia cells. PMID:9047395

Francastel, C; Augery-Bourget, Y; Prenant, M; Walters, M; Martin, D I; Robert-Lézénès, J

1997-02-20

345

Neutralizing activities of caprine antibodies towards conserved regions of the HCV envelope glycoprotein E2  

PubMed Central

Anti HCV vaccine is not currently available and the present antiviral therapies fail to cure approximately half of the treated HCV patients. This study was designed to assess the immunogenic properties of genetically conserved peptides derived from the C-terminal region of HVR-1 and test their neutralizing activities in a step towards developing therapeutic and/or prophylactic immunogens against HCV infection. Antibodies were generated by vaccination of goats with synthetic peptides derived from HCV E2. Viral neutralizing capacity of the generated anti E2 antibodies was tested using in vitro assays. Goats immunized with E2 synthetic peptides termed p412 [a.a 412-419], p430 [a.a 430-447] and p517 [a.a 517-531] generated high titers of antibody responses 2 to 4.5 fold higher than comparable titers of antibodies to the same epitopes in chronic HCV patients. In post infection experiments of native HCV into cultured Huh7.5 cells anti p412 and anti p 517 were proven to be neutralizing to HCV genotype 4a from patients' sera (87.5% and 75% respectively). On the contrary anti p430 exhibited weak viral neutralization capacity on the same samples (31.25%). Furthermore Ab mixes containing anti p430 exhibited reduced viral neutralization properties. From these experiments one could predict that neutralization by Abs towards different E2-epitopes varies considerably and success in the enrichment of neutralization epitope-specific antibodies may be accompanied by favorable results in combating HCV infection. Also, E2 conserved peptides p517 and p412 represent potential components of a candidate peptide vaccine against HCV infection. PMID:21819575

2011-01-01

346

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

347

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

348

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

349

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

PubMed Central

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

Garcia-Jove Navarro, Marina; Basset, Celine; Arcondeguy, Tania; Touriol, Christian; Perez, Guillaume; Prats, Herve; Lacazette, Eric

2013-01-01

350

How Does (E)-2-(Acetamidomethylene)succinate Bind to Its Hydrolase? From the Binding Process to the Final Result  

PubMed Central

The binding of (E)-2-(acetamidomethylene)succinate (E-2AMS) to E-2AMS hydrolase is crucial for biological function of the enzyme and the last step reaction of vitamin B6 biological degradation. In the present study, several molecular simulation methods, including molecular docking, conventional molecular dynamics (MD), steered MD (SMD), and free energy calculation methods, were properly integrated to investigate the detailed binding process of E-2AMS to its hydrolase and to assign the optimal enzyme-substrate complex conformation. It was demonstrated that the substrate binding conformation with trans-form amide bond is energetically preferred conformation, in which E-2AMS's pose not only ensures hydrogen bond formation of its amide oxygen atom with the vicinal oxyanion hole but also provides probability of the hydrophobic interaction between its methyl moiety and the related enzyme's hydrophobic cavity. Several key residues, Arg146, Arg167, Tyr168, Arg179, and Tyr259, orientate the E-2AMS's pose and stabilize its conformation in the active site via the hydrogen bond interaction with E-2AMS. Sequentially, the binding process of E-2AMS to E-2AMS hydrolase was studied by SMD simulation, which shows the surprising conformational reversal of E-2AMS. Several important intermediate structures and some significant residues were identified in the simulation. It is stressed that Arg146 and Arg167 are two pivotal residues responsible for the conformational reversal of E-2AMS in the binding or unbinding. Our research has shed light onto the full binding process of the substrate to E-2AMS hydrolase, which could provide more penetrating insight into the interaction of E-2AMS with the enzyme and would help in the further exploration on the catalysis mechanism. PMID:23308285

Zhang, Ji-Long; Zheng, Qing-Chuan; Li, Zheng-Qiang; Zhang, Hong-Xing

2013-01-01

351

Retinoblastoma-repression of E2F-dependent transcription depends on the ability of the retinoblastoma protein to interact with E2F and is abrogated by the adenovirus E1A oncoprotein.  

PubMed Central

The product of the retinoblastoma tumor suppressor gene interacts with the transcription factor E2F. Two distinct types of interactions can be detected between the retinoblastoma gene product (Rb) and E2F. The first type involves an Rb-binding protein, RBP60. The Rb/E2F complex formed in the presence of RBP60 is able to bind DNA and migrates with a distinct mobility in gel retardation assays. The second type of Rb/E2F complex is seen in the absence of RBP60. This second type of Rb/E2F complex does not form a band-shift complex in gel retardation assays and its formation results in an apparent inhibition or loss of the DNA binding activity of E2F. Using a series of Rb-mutants we show that these two types of Rb/E2F complexes depend on common domains of the Rb protein. The T/E1A-binding region as well as the carboxyl-terminus of the Rb protein are critical for these two types of Rb/E2F interactions. We also show that the retinoblastoma protein represses the E2F-dependent transcription, and this Rb-repression of the E2F-dependent transcription depends on the ability of Rb to interact with E2F. Moreover, the adenovirus E1A gene product, which binds Rb, counteracts the Rb-repression and restores E2F-dependent transcription. Images PMID:1461728

Arroyo, M; Raychaudhuri, P

1992-01-01

352

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

353

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

354

Inter-band B(E2) transition strengths in odd-mass heavy deformed nuclei  

E-print Network

Inter-band B(E2) transition strengths between different normal parity bands in 163Dy and 165Er are described using the pseudo-SU(3) model. The Hamiltonian includes Nilsson single-particle energies, quadrupole-quadrupole and pairing interactions with fixed, parametrized strengths, and three extra rotor terms used to fine tune the energy spectra. In addition to inter-band transitions, the energy spectra and the ground state intra-band B(E2) strengths are reported. The results show the pseudo-SU(3) shell model to be a powerful microscopic theory for a description of the normal parity sector in heavy deformed odd-A nuclei.

C. E. Vargas; J. G. Hirsch; J. P. Draayer

2001-09-21

355

$E1-E2$ interference in the Coulomb dissociation of $^8$B  

E-print Network

We investigate the effects arising out of the $E1 - E2$ interference in the Coulomb dissociation of $^8$B at beam energies below and around 50 MeV/nucleon. The theory has been formulated within a first order semiclassical scheme of Coulomb excitation, in which both the ground state and the continuum state wave functions of $^8$B enter as inputs. We find that the magnitude of the interference could be large in some cases. However, there are some specific observables which are free from the effects of the $E1 - E2$ interference, which is independent of the models used to describe the structure of $^8$B. This will be useful for the analysis of the breakup data in relation to the extraction of the astrophysical factor $S_{17}(0)$.

P. Banerjee; R. Shyam

2000-08-14

356

Gradual decrease of conductance of an adiabatic ballistic constriction below 2 e2 /h  

NASA Astrophysics Data System (ADS)

We have performed four-terminal conductance measurements of a one-dimensional (1D) channel in which it is possible to modulate the potential profile using three overlaying finger gates. In such a 1D ballistic structure we have observed that the conductance steps show a gradual decrease from 2 e2 /h to 0.97×2 e2 /h with increasing negative finger gate voltage in a short, clean 1D constriction. We suggest this phenomenon is due to differing shifts of 1D subbands with changing spilt-gate voltage. Both a simple analytical estimate for an adiabatic constriction and a realistic modeling of the device give the same magnitude of the conductance decrease as observed in our experiments.

Liang, C.-T.; Tkachenko, O. A.; Tkachenko, V. A.; Baksheyev, D. G.; Simmons, M. Y.; Ritchie, D. A.; Pepper, M.

2004-11-01

357

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

358

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.; Naar, Anders; Cam, Hieu; Gregory, Richard; Dynlacht, Brian David

2001-01-01

359

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

360

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

NASA Technical Reports Server (NTRS)

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

Oriti, Salvatore; Wilson, Scott

2011-01-01

361

Subdivision of the pestivirus genus based on envelope glycoprotein E2.  

PubMed

Conventionally, the genus Pestivirus of the family Flaviviridae has been divided into bovine viral diarrhea virus (BVDV), classical swine fever virus (CSFV), and border disease virus (BDV). To date, BDV and BVDV have been isolated from different species, whereas CSFV seems to be restricted to swine. Pestiviruses are structurally and antigenically closely related. Envelope glycoprotein E2 is the most immunogenic and most variable protein of pestiviruses. We cloned E2 genes of many different pestivirus strains, including those from a deer and a giraffe. The E2 genes were transiently expressed, characterized with monoclonal antibodies, sequenced, and compared. Based on these data, we can delineate six major groups within the Pestivirus genus. Four groups correspond to defined genotypes, whereas the two other groups could be new genotypes within the Pestivirus genus. One group comprises CSFV strains isolated from swine. A second group consists of BDV strains Moredun, L83, and X818, which have been isolated from sheep, and strain F from swine. A third group contains strain BD78 from sheep, strain 5250 from swine, and strain 178003 from cattle. On the basis of E2, these viruses are very similar to BVDV strains associated with acute severe outbreaks of bovine viral diarrhea, so-called type 2 BVDV. The fourth group consists of BVDV strains originating predominantly from cattle. This BVDV group can be divided into two subtypes or subgroups BVDV Ia and Ib: BVDV Ia contains viruses from the United States, such as like NADL and Oregon, and some others, such as 150022 and 1138 from Europe. Subgroup BVDV Ib contains strain Osloss and several Dutch isolates. The fifth and sixth "groups" could be proposed as two new genotypes and contain strains Deer and Giraffe, respectively. PMID:9356345

van Rijn, P A; van Gennip, H G; Leendertse, C H; Bruschke, C J; Paton, D J; Moormann, R J; van Oirschot, J T

1997-10-27

362

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

363

Exact Results on e+ e- --> e+ e- + 2 Photons at SLC/LEP Energies  

E-print Network

We use the spinor methods of the CALKUL collaboration, as realized by Xu, Zhang and Chang, to calculate the differential cross section for e+ e- --> e+ e- + 2 photons for c.m.s. energies in the SLC/LEP regime. An explicit complete formula for the respective cross section is obtained. The leading log approximation is used to check the formula. Applications of the formula to high precision luminosity calculations at SLC/LEP are discussed.

S. Jadach; B. F. L. Ward; S. A. Yost

1992-11-16

364

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

365

Mangiferin inhibits cyclooxygenase-2 expression and prostaglandin E 2 production in activated rat microglial cells  

Microsoft Academic Search

Mangiferin, a naturally occurring glucosylxanthone, has potent antioxidant and anti-inflammatory properties, as demonstrated in several reports. However, very limited information is available on the effects of this natural polyphenol on microglial activation. Thus, the aim of this study was to examine whether mangiferin is able to reduce prostaglandin E2 (PGE2) and 8-iso-prostaglandin F2? (8-iso-PGF2?) production by lipopolysaccharide (LPS)-activated primary rat

Harsharan S. Bhatia; Eduardo Candelario-Jalil; Antonio C. Pinheiro de Oliveira; Olumayokun A. Olajide; Gregorio Martínez-Sánchez; Bernd L. Fiebich

2008-01-01

366

Constraining the (gamma,pi) amplitude for E2 N->delta  

E-print Network

A recent analysis of pion photo-production multipoles using p(g,pi0) data from Mainz is repeated, successively adding constraints from other observables and varying the number of fitted partial waves. The original analysis is shown to have been underconstrained and suffered from ambiguities. The inclusion of additional observables in our analysis results in a very different, but stable, ratio of E2/M1 multipoles at the delta that is consistent with the Mainz data set.

A. M. Sandorfi; J. Tonnison; S. Hoblit

1997-07-17

367

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

368

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

Microsoft Academic Search

A three-dimensional reconstruction of Sindbis virus at 7.0 Å resolution presented here provides a detailed view of the virion structure and includes structural evidence for key interactions that occur between the capsid protein (CP) and transmembrane (TM) glycoproteins E1 and E2. Based on crystal structures of component proteins and homology modeling, we constructed a nearly complete, pseudo-atomic model of the virus.

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

369

A molecular basis for phosphorylation-dependent SUMO conjugation by the E2 UBC9  

Microsoft Academic Search

Phosphorylation and small ubiquitin-like modifier (SUMO) conjugation contribute to the spatial and temporal regulation of substrates containing phosphorylation-dependent SUMO consensus motifs (PDSMs). Myocyte-enhancement factor 2 (MEF2) is a transcription factor and PDSM substrate whose modification by SUMO drives postsynaptic dendritic differentiation. NMR analysis revealed that the human SUMO E2 interacted with model substrates for phosphorylated and nonphosphorylated MEF2 in similar

Firaz Mohideen; Allan D Capili; Parizad M Bilimoria; Tomoko Yamada; Azad Bonni; Christopher D Lima

2009-01-01

370

Electrophile-Modified Lipoic Derivatives of PDC-E2 Elicits Anti-mitochondrial Antibody Reactivity  

PubMed Central

Our laboratory has hypothesized that xenobiotic modification of the native lipoyl moiety of the major mitochondrial autoantigen, the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2), may lead to loss of self-tolerance in primary biliary cirrhosis (PBC). This thesis is based on the finding of readily detectable levels of immunoreactivity of PBC sera against extensive panels of protein microarrays containing mimics of the inner lipoyl domain of PDC-E2 and subsequent quantitative structure-activity relationships (QSARs). Importantly, we have demonstrated that murine immunization with one such mimic, 2-octynoic acid coupled to bovine serum albumin (BSA), induces antimitochondrial antibodies (AMAs) and cholangitis. Based upon these data, we have focused on covalent modifications of the lipoic acid disulfide ring and subsequent analysis of such xenobiotics coupled to a 15mer of PDC-E2 for immunoreactivity against a broad panel of sera from patients with PBC and controls. Our results demonstrate that AMA-positive PBC sera demonstrate marked reactivity against 6,8-bis(acetylthio)octanoic acid, implying that chemical modification of the lipoyl ring, i.e. disruption of the S-S disulfide, renders lipoic acid to its reduced form that will promote xenobiotic modification. This observation is particularly significant in light of the function of the lipoyl1oiety in electron transport of which the catalytic disulfide constantly opens and closes and, thus, raises the intriguing thesis that common electrophilic agents, i.e. acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs), may lead to xenobiotic modification in genetically susceptible individuals that results in the generation of AMAs and ultimately clinical PBC. PMID:21763105

Naiyanetr, Phornnop; Butler, Jeffrey D.; Meng, Liping; Pfeiff, Janice; Kenny, Thomas P.; Guggenheim, Kathryn G.; Reiger, Roman; Lam, Kit; Kurth, Mark J.; Ansari, Aftab. A.; Coppel, Ross L.; Lopez-Hoyos, Marcos; Gershwin, M. Eric; Leung, Patrick S.C.

2011-01-01

371

The aerodynamics performance of Blended Wing Body Baseline-II E2  

Microsoft Academic Search

the BWB. The aerodynamic characteristics prediction of BWB­ Baseline II E2 aircraft was obtained through CFO analysis using unstructured mesh and standard one - equation turbulence model, Spalart-Allmaras was selected in the investigations. Lift coefficient (CL), drag coefficient (CD) and moment coefficient (CM) were studied at flight condition of Mach 0.1 (?34 m\\/s) at different angles of attack, fL. The

Zurriati M. Ali; Wahyu Kuntjoro; Wirachman Wisnoe; Rizal Efendy M. Nasir; Firdaus Mohamad; Nor F. Reduan

2011-01-01

372

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

Microsoft Academic Search

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

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

1995-01-01

373

Photochemistry of nitro-substituted ( E)-2-azachalcones with theoretical calculations and biological activities  

Microsoft Academic Search

Four new stereoselective dimerization products (4a–c, 5) of m- and p-nitro-substituted (E)-2-azachalcones (2 and 3) were synthesized and tested for antimicrobial and antioxidant activities. Compounds 1–3 showed very good antimicrobial activities against all the tested microorganisms, Escherichia coli, Yersinia pseudotuberculosis, Pseudomonas aeruginosa, Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, and Candida albicans. Five of the compounds tested were radical

Nurettin Yayl?; Osman Üçüncü; Ahmet Ya?ar; Nuran Yayl?; Nesibe Arslan Burnaz; ?engül Alpay Karao?lu; Murat Küçük

2009-01-01

374

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

375

Chang’E-2 satellite asymmetric-descent orbit control technology  

Microsoft Academic Search

To accomplish high-resolution imaging of the preselected landing area, it was necessary for the Chang’E-2 mission to perform\\u000a orbital maneuvering on the far side of the moon to meet the conditional height requirement of the imaging area. Engine shutdown\\u000a would be executed invisibly on the back side of the moon if the descent maneuver mode opposite to the target perilune

JianLiang Zhou; Yong Liu; DeYun Peng; FengCai Zhao

2011-01-01

376

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

377

E-screen and vitellogenin assay for the detection of the estrogenic activity of alkylphenols and trace elements.  

PubMed

The estrogenic potential of 4-nonylphenol (4-NP), 4-octylphenol (4-OP), p-t-octylphenol (p-t-OP) and three trace elements, lead (Pb), copper (Cu) and cadmium (Cd(NO(3))(2) and CdCl(2)), were compared in two different tests, a proliferation assay with estrogen receptor-positive human MCF-7 breast cancer cells (E-screen) and the induction of vitellogenin (Vtg) in juvenile goldfish (Carassius auratus). The results showed differences in the bioassays' sensitivity and potency with the following order: E-screen>Vtg. Among alkylphenols, both in vitro and in vivo, 4-NP and 4-OP showed the highest estrogen-like activity while p-t-OP was inferior. For trace elements, Pb and Cu showed estrogenic activity in vitro and they were also active in vivo. A range of estrogenicity was observed for different species of cadmium (Cd(NO(3))(2) and CdCl(2)) which showed the highest relative proliferative effect (RPE %) in vitro, when compared with the 17beta-estradiol (E(2); RPE=100%) but, Cd(NO(3))(2) was not estrogenic in vivo. The results suggest that an integrated approach using in vitro and in vivo assays is necessary for a correct risk assessment of the endocrine disrupting activity induced by environmental contaminants. PMID:20197112

Isidori, Marina; Cangiano, Margherita; Palermo, Francesco A; Parrella, Alfredo

2010-06-01

378

Increased expression of Nrf2/ARE-dependent anti-oxidant proteins in tamoxifen-resistant breast cancer cells.  

PubMed

Acquired resistance to tamoxifen (TAM) is a serious therapeutic problem in breast cancer patients. In this study, we found that the expressions of anti-oxidant proteins (gamma-glutamylcysteine ligase heavy chain (gamma-GCL h), heme oxygenase-1, thioredoxin and peroxiredoxin1) in TAM-resistant MCF-7 (TAMR-MCF-7) cells were higher than control MCF-7 cells. Molecular analyses using antioxidant response element (ARE)-containing reporters and gel-shift supported the critical role of NF-E2-related factor2 (Nrf2)/ARE in the overexpression of antioxidant proteins in TAMR-MCF-7 cells. Intracellular peroxide production was significantly decreased in TAMR-MCF-7 cells and TAM resistance was partially reversed by Nrf2 siRNA. The basal phosphorylation of extracellular signal-regulated kinase (ERK) and p38 kinase were increased in the TAMR-MCF-7 cells and the inhibition of ERK significantly decreased the activity of minimal ARE reporter and gamma-GCL h protein expression in TAMR-MCF-7 cells. However, exposure of TAMR-MCF-7 cells to 17-beta-estradiol or ICI-182,780 did not significantly change gamma-GCL h expression. These results suggest that the persistent activation of Nrf2/ARE is critical for the enhanced expression of anti-oxidant proteins in TAM-resistant breast cancer cells and the pathway of ERK, but not of estrogen receptor signaling are involved in the up-regulation of Nrf2/ARE. PMID:18539158

Kim, Sang Kyum; Yang, Jin Won; Kim, Mi Ra; Roh, Sang Hee; Kim, Hyung Gyun; Lee, Kwang Youl; Jeong, Hye Gwang; Kang, Keon Wook

2008-08-15

379

Measuring multiple hormones from a single water sample using enzyme immunoassays.  

PubMed

Many aquatic species, such as teleosts, release into the water and detect multiple bioactive substances to assist in schooling, migration, alarm reactions, and to stimulate behavioral and physiological responses during reproduction and in parent-offspring interactions. Understanding the complex relationship between hormones, behavior and their function in communication requires the simultaneous examination of multiple circulating hormones. However, repeated blood sampling within a short time period is not possible in smaller animals without impacting the very behaviors under investigation. The non-invasive technique of collecting and measuring hormone values in holding water using either radioimmunoassay (RIA) or enzyme immunoassay (EIA) is becoming widely used in teleost research. Commercial assay kits in particular enable rapid and reliable data generation, yet their assay buffers are often specific and potentially incompatible with each other, which can hinder measuring multiple hormones from the same sample. We present here the validation and application of a "nested" elution technique we developed that allows for repeated sampling of multiple reproductive hormones - testosterone (T), 17beta-estradiol (E2), progesterone (P), prostaglandin F(2 alpha) (PGF) and 11-ketotestosterone (11KT) - from individual samples of animal holding water by using commercial EIA systems. Our results show that when using appropriate controls to account for possible technical and biological confounds, this technique provides a powerful new tool for research in aquatic endocrinology and physiology. PMID:19607832

Kidd, Celeste E; Kidd, Michael R; Hofmann, Hans A

2010-01-15

380

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

PubMed

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

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

2001-08-01

381

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

382

Rapid, Estrogen Receptor-Mediated Signaling: Why Is the Endothelium So Special?  

NSDL National Science Digital Library

Classical, ligand-activated genomic effects of estrogen receptors (ERs) were once thought to mediate all estrogen responses. It is now accepted that rapid, nongenomic responses, mediated by ER-containing membrane complexes, occur in many tissues. The endothelium is a major target of such responses and is the critical regulatory tissue that, when normally functional, determines a state of "vascular health." When dysfunctional, the phenotypic and functional alterations result in vascular pathology, the most common form of which is atherosclerosis. Nitric oxide (NO) is a vascular protective substance generated by endothelial NO synthase (eNOS) in endothelial cells. The engagement of membrane ERs by 17&beta;-estradiol (E2) is a potent stimulus to eNOS activation and NO release. Here, we describe the multimolecular components of ER-containing membrane complex assembly and the mechanisms directing ER targeting to caveolae microdomains in the plasma membrane. We discuss the possibility that various ERα splice forms, expressed in endothelial cells, may be particularly efficient signal transducers and may use classical receptor domains for membrane targeting and insertion. Finally, we discuss the biomedical ramifications of ER-mediated endothelial activation, including the controversies surrounding hormone replacement therapy and cardiovascular disease.

Kyung Hee Kim (Yale University School of Medicine;Divisions of Cardiovascular Medicine and Immunobiology at the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory REV); Jeffrey R. Bender (Yale University School of Medicine;Divisions of Cardiovascular Medicine and Immunobiology at the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory REV)

2005-06-14

383

E3 ligases determine ubiquitination site and conjugate type by enforcing specificity on E2 enzymes.  

PubMed

Ubiquitin-conjugating enzymes (E2s) have a dominant role in determining which of the seven lysine residues of ubiquitin is used for polyubiquitination. Here we show that tethering of a substrate to an E2 enzyme in the absence of an E3 ubiquitin ligase is sufficient to promote its ubiquitination, whereas the type of the ubiquitin conjugates and the identity of the target lysine on the substrate are promiscuous. In contrast, when an E3 enzyme is introduced, a clear decision between mono- and polyubiquitination is made, and the conjugation type as well as the identity of the target lysine residue on the substrate becomes highly specific. These features of the E3 can be further regulated by auxiliary factors as exemplified by MDMX (Murine Double Minute X). In fact, we show that this interactor reconfigures MDM2-dependent ubiquitination of p53. Based on several model systems, we propose that although interaction with an E2 is sufficient to promote substrate ubiquitination the E3 molds the reaction into a specific, physiologically relevant protein modification. PMID:21965653

David, Yael; Ternette, Nicola; Edelmann, Mariola J; Ziv, Tamar; Gayer, Batya; Sertchook, Rotem; Dadon, Yakir; Kessler, Benedikt M; Navon, Ami

2011-12-23

384

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

385

Characterisation of mouse monoclonal antibodies targeting linear epitopes on Chikungunya virus E2 glycoprotein.  

PubMed

Chikungunya virus (CHIKV) is a mosquito-borne arbovirus which has recently re-emerged globally and poses a major threat to public health. Infection leads to severe arthralgia, and disease management remains supportive in the absence of vaccines and anti-viral interventions. The high specificities of monoclonal antibodies (mAbs) have been exploited in immunodiagnostics and immunotherapy in recent decades. In this study, eight different clones of mAbs were generated and characterised. These mAbs targeted the linear epitopes on the CHIKV E2 envelope glycoprotein, which is the major target antigen during infection. All the mAbs showed binding activity against the purified CHIKV virion or recombinant E2 when analysed by immunofluorescence, ELISA and Western blot. The epitopes of each mAb were mapped by overlapping synthetic peptide-based ELISA. The epitopes are distributed at different functional domains of E2 glycoprotein, namely at domain A, junctions of ?-ribbons with domains A and B, and domain C. Alignment of mAb epitope sequences revealed that some are well-conserved within different genotypes of CHIKV, while some are identical to and likely to cross-react with the closely-related alphavirus O'nyong-nyong virus. These mAbs with their mapped epitopes are useful for the development of diagnostic or research tools, including immunofluorescence, ELISA and Western blot. PMID:24134938

Chua, Chong Long; Chan, Yoke Fun; Sam, I-Ching

2014-01-01

386

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. $0 < r_Q < 1$. There are a few cases where $r_Q$ is bigger than one, especially for light nuclei.

Sean Yeager; Larry Zamick

2008-07-29

387

Prospects for X-ray Studies of Galaxy Clusters with Astro-E2/XRS  

E-print Network

The Astro-E2 high resolution X-Ray Spectrometer (XRS) is expected to provide a major enhancement in study of clusters of galaxies. Astro-E2 is the fifth Japanese X-ray astronomy observatory, which is scheduled for launch in early 2005. The XRS instrument, developed under a Japan-US collaboration, is an X-ray microcalorimeter with a capability of observing extended objects, and a high energy resolution of about 6 eV at 6 keV. The spectral resolving power is 20 times higher than CCDs over the 0.5-10 keV energy band. We have obtained several new results of clusters with Chandra and XMM, which show that high-resolution imaging spectroscopy can clarify some outstanding questions. New sciences from Astro-E2 include the first clear measurement of gas velocities, determination of ion and electron temperatures, and electron densities based on the resolved line features. We will describe the XRS instrument design, and present simulations of the expected performance.

T. Furusho; K. Mitsuda; N. Yamasaki; R. Fujimoto; T. Ohashi

2004-01-23

388

Coordinate regulation of Fanconi anemia gene expression occurs through the Rb/E2F pathway  

PubMed Central

Fanconi anemia (FA) is a genome instability syndrome that is characterized by progressive bone marrow failure and a high risk of cancer. FA patients are particularly susceptible to leukemia as well as squamous cell carcinoma (SCCs) of the head and neck, anogenital region and skin. Thirteen complementation groups and the corresponding FA genes have been identified, and their protein products assemble into nuclear core complexes during DNA damage responses. Much progress has been made in our understanding of post-translational FA protein modifications and physical interactions. In contrast, little is known about the control of protein availability at the level of transcription. We report here that multiple FA proteins were downregulated during the proliferative arrest of primary human keratinocytes and HeLa cells, and that the observed regulation was at a transcriptional level. Proliferative stimuli such as expression of HPV16 E7 as well as E2F1 overexpression in primary cells resulted in coordinate FA upregulation. To define the underlying mechanism, we examined the endogenous FANCD2 promoter, and detected regulated binding of members of the E2F/Rb family in chromatin immunoprecipitation assays. Finally, a 1 kb promoter fragment was sufficient to confer E2F/Rb regulation in reporter assays. Taken together, our data demonstrate FA gene co-regulation in synchrony with the cell cycle and suggest that deregulated expression of individual FA genes - in addition to FA gene mutation - may promote FA related human cancer. PMID:18438432

Hoskins, Elizabeth E.; Gunawardena, Ranjaka W.; Habash, Kristen B.; Wise-Draper, Trisha M.; Jansen, Michael; Knudsen, Erik S.; Wells, Susanne I.

2009-01-01

389

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

390

Mitochondrial stress engages E2F1 apoptotic signaling to cause deafness  

PubMed Central

SUMMARY Mitochondrial dysfunction causes poorly understood tissue-specific pathology stemming from primary defects in respiration, coupled with altered reactive oxygen species (ROS), metabolic signaling and apoptosis. The A1555G mtDNA mutation that causes maternally inherited deafness disrupts mitocho