80 research outputs found

    A Novel Gonadotropin-Releasing Hormone 1 (Gnrh1) Enhancer-Derived Noncoding RNA Regulates Gnrh1 Gene Expression in GnRH Neuronal Cell Models.

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    Gonadotropin-releasing hormone (GnRH), a neuropeptide released from a small population of neurons in the hypothalamus, is the central mediator of the hypothalamic-pituitary-gonadal axis, and is required for normal reproductive development and function. Evolutionarily conserved regulatory elements in the mouse, rat, and human Gnrh1 gene include three enhancers and the proximal promoter, which confer Gnrh1 gene expression specifically in GnRH neurons. In immortalized mouse hypothalamic GnRH (GT1-7) neurons, which show pulsatile GnRH release in culture, RNA sequencing and RT-qPCR revealed that expression of a novel long noncoding RNA at Gnrh1 enhancer 1 correlates with high levels of GnRH mRNA expression. In GT1-7 neurons, which contain a transgene carrying 3 kb of the rat Gnrh1 regulatory region, both the mouse and rat Gnrh1 enhancer-derived noncoding RNAs (GnRH-E1 RNAs) are expressed. We investigated the characteristics and function of the endogenous mouse GnRH-E1 RNA. Strand-specific RT-PCR analysis of GnRH-E1 RNA in GT1-7 cells revealed GnRH-E1 RNAs that are transcribed in the sense and antisense directions from distinct 5' start sites, are 3' polyadenylated, and are over 2 kb in length. These RNAs are localized in the nucleus and have a half-life of over 8 hours. In GT1-7 neurons, siRNA knockdown of mouse GnRH-E1 RNA resulted in a significant decrease in the expression of the Gnrh1 primary transcript and Gnrh1 mRNA. Over-expression of either the sense or antisense mouse GnRH-E1 RNA in immature, migratory GnRH (GN11) neurons, which do not express either GnRH-E1 RNA or GnRH mRNA, induced the transcriptional activity of co-transfected rat Gnrh1 gene regulatory elements, where the induction requires the presence of the rat Gnrh1 promoter. Together, these data indicate that GnRH-E1 RNA is an inducer of Gnrh1 gene expression. GnRH-E1 RNA may play an important role in the development and maturation of GnRH neurons

    Measurement of the Negative Muon Anomalous Magnetic Moment to 0.7 ppm

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    The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 parts per million (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement of the negative muon. The result a_mu= 11 659 214(8)(3) \times 10^{-10} (0.7 ppm), where the first uncertainty is statistical and the second is sytematic, is consistend with previous measurements of the anomaly for the positive and negative muon. The average for the muon anomaly a_{mu}(exp) = 11 659 208(6) \times 10^{-10} (0.5ppm).Comment: 4 pages, 4 figures, submitted to Physical Review Letters, revised to reflect referee comments. Text further revised to reflect additional referee comments and a corrected Fig. 3 replaces the older versio

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

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    The spin precession frequency of muons stored in the (g−2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaμ+−ωaμ−\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaμ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=−(1.0±1.1)×10−23b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mμdZ0+HXY)=(1.8±6.0×10−23)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇ⊥μ+<1.4×10−24\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇ⊥μ−<2.6×10−24\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion

    The Muon Anomalous Magnetic Moment and the Standard Model

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    The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 Collaboration reduces the uncertainty on the world average of a_mu to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly.Comment: Plenary Talk; PANIC'02 XVI Particles and Nuclear International Conference, Osaka, Japan; Sept. 30 - Oct. 4, 2002; Report describes the published 0.7 ppm result and updates the theory statu

    An Improved Limit on the Muon Electric Dipole Moment

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    Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d=-0.1(0.9)E-19 e-cm, are all consistent with zero, we set a new muon EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.Comment: 19 pages, 15 figures, 7 table

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

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    The spin precession frequency of muons stored in the (g−2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaμ+−ωaμ−\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaμ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=−(1.0±1.1)×10−23b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mμdZ0+HXY)=(1.8±6.0×10−23)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇ⊥μ+<1.4×10−24\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇ⊥μ−<2.6×10−24\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion

    Final Report of the Muon E821 Anomalous Magnetic Moment Measurement at BNL

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    We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a_mu = (g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a_mu(Expt) = 11 659 208.0(5.4)(3.3) x 10^-10, where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a_mu includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, ~0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e+e- hadronic cross sections, lie 2.2 - 2.7 standard deviations below the experimental result.Comment: Summary paper of E821 Collaboration measurements of the muon anomalous magnetic moment, each reported earlier in Letters or Brief Reports; 96 pages, 41 figures, 16 tables. Revised version submitted to PR

    News from the Muon (g-2) Experiment at BNL

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    The magnetic moment anomaly a_mu = (g_mu - 2) / 2 of the positive muon has been measured at the Brookhaven Alternating Gradient Synchrotron with an uncertainty of 0.7 ppm. The new result, based on data taken in 2000, agrees well with previous measurements. Standard Model evaluations currently differ from the experimental result by 1.6 to 3.0 standard deviations.Comment: Talk presented at RADCOR - Loops and Legs 2002, Kloster Banz, Germany, September 8-13 2002, to be published in Nuclear Physics B (Proc. Suppl.); 5 pages, 3 figure

    Interactions between folate intake and genetic predictors of gene expression levels associated with colorectal cancer risk

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    Observational studies have shown higher folate consumption to be associated with lower risk of colorectal cancer (CRC). Understanding whether and how genetic risk factors interact with folate could further elucidate the underlying mechanism. Aggregating functionally relevant genetic variants in set-based variant testing has higher power to detect gene-environment (G x E) interactions and may provide information on the underlying biological pathway. We investigated interactions between folate consumption and predicted gene expression on colorectal cancer risk across the genome. We used variant weights from the PrediXcan models of colon tissue-specific gene expression as a priori variant information for a set-based G x E approach. We harmonized total folate intake (mcg/day) based on dietary intake and supplemental use across cohort and case-control studies and calculated sex and study specific quantiles. Analyses were performed using a mixed effects score tests for interactions between folate and genetically predicted expression of 4839 genes with available genetically predicted expression. We pooled results across 23 studies for a total of 13,498 cases with colorectal tumors and 13,918 controls of European ancestry. We used a false discovery rate of 0.2 to identify genes with suggestive evidence of an interaction. We found suggestive evidence of interaction with folate intake on CRC risk for genes including glutathione S-Transferase Alpha 1 (GSTA1; p = 4.3E-4), Tonsuko Like, DNA Repair Protein (TONSL; p = 4.3E-4), and Aspartylglucosaminidase (AGA: p = 4.5E-4). We identified three genes involved in preventing or repairing DNA damage that may interact with folate consumption to alter CRC risk. Glutathione is an antioxidant, preventing cellular damage and is a downstream metabolite of homocysteine and metabolized by GSTA1. TONSL is part of a complex that functions in the recovery of double strand breaks and AGA plays a role in lysosomal breakdown of glycoprotein
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