25 research outputs found

    The RNA editing enzyme ADAR2 restricts L1 mobility

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    Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosines to inosines in double-stranded RNAs (RNA editing A-to-I). ADAR1 and ADAR2 were previously reported as HIV-1 proviral factors. The aim of this study was to investigate the composition of the ADAR2 ribonucleoprotein complex during HIV-1 expression. By using a dual-tag affinity purification procedure in cells expressing HIV-1 followed by mass spectrometry analysis, we identified 10 non-ribosomal ADAR2-interacting factors. A significant fraction of these proteins was previously found associated to the Long INterspersed Element 1 (LINE1 or L1) ribonucleoparticles and to regulate the life cycle of L1 retrotransposons. Considering that we previously demonstrated that ADAR1 is an inhibitor of LINE-1 retrotransposon activity, we investigated whether also ADAR2 played a similar function. To reach this goal, we performed specific cell culture retrotransposition assays in cells overexpressing or ablated for ADAR2. These experiments unveil a novel function of ADAR2 as suppressor of L1 retrotransposition. Furthermore, we showed that ADAR2 binds the basal L1 RNP complex. Overall, these data support the role of ADAR2 as regulator of L1 life cycle

    Physical and geometrical parameters of the binary system gliese 150.2

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    The speckle interferometric binary system Gl 150.2 (HIP17491) is analyzed using atmosphere modeling and dynamical analysis simultaneously. A synthetic spectral energy distribution (SED) for each of the two components of the system is built using Kurucz blanketed models. These SEDs are combined together to form the total flux, which is compared with the observed one in an iterative method to get the best fit. The parameters of the individual components which lead to the best fit are: T eff A = 5350 ± 50 K, T eff B = 4400 ± 50 K, log g A = 4.40 ± 0.05, log g B = 4.68 ± 0.05, R A = 0.95 ± 0.06R ⊙, R B = 0.58 ± 0.06R ⊙, and π = 38.63 ± 0.79 mas, as given by the modified Hipparcos measurement. A modified orbit of the system is introduced and compared with earlier orbits. Hence, the masses of the two components are derived from the coincidence between the atmosphere modeling and dynamical analysis. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, the spectral types and luminosity classes of the two components are found to be G9.5V and K7V for the primary and secondary stars respectively, with an age of about 8 Gyr. Finally, the positions of both components on the H-R diagram are plotted, and the formation and evolution of the system are discussed. © 2014 Pleiades Publishing, Ltd

    Investigation of Some Physical Properties of Accretion Induced Collapse in Producing Millisecond Pulsars

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    We investigate some physical characteristics of Millisecond Pulsar (MSP) such as magnetic fields, spin periods and masses, that are produced by Accretion Induced Collapse (AIC) of an accreting white dwarf (WD) in stellar binary systems. We also investigate the changes of these characteristics during the mass-transfer phase of the system in its way to become a MSP. Our approach allows us to follow the changes in magnetic fields and spin periods during the conversion of WDs to MSPs via AIC process. We focus our attention mainly on the massive binary WDs (M > 1.0Msun) forming cataclysmic variables, that could potentially evolve to reach Chandrasekhar limit, thereafter they collapse and become MSPs. Knowledge about these parameters might be useful for further modeling of the observed features of AIC.Comment: 9 Pages, 4 figure

    Physical and geometrical parameters of the binary system gliese 150.2

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    The speckle interferometric binary system Gl 150.2 (HIP17491) is analyzed using atmosphere modeling and dynamical analysis simultaneously. A synthetic spectral energy distribution (SED) for each of the two components of the system is built using Kurucz blanketed models. These SEDs are combined together to form the total flux, which is compared with the observed one in an iterative method to get the best fit. The parameters of the individual components which lead to the best fit are: T eff A = 5350 ± 50 K, T eff B = 4400 ± 50 K, log g A = 4.40 ± 0.05, log g B = 4.68 ± 0.05, R A = 0.95 ± 0.06R ⊙, R B = 0.58 ± 0.06R ⊙, and π = 38.63 ± 0.79 mas, as given by the modified Hipparcos measurement. A modified orbit of the system is introduced and compared with earlier orbits. Hence, the masses of the two components are derived from the coincidence between the atmosphere modeling and dynamical analysis. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, the spectral types and luminosity classes of the two components are found to be G9.5V and K7V for the primary and secondary stars respectively, with an age of about 8 Gyr. Finally, the positions of both components on the H-R diagram are plotted, and the formation and evolution of the system are discussed. © 2014 Pleiades Publishing, Ltd

    Physical and geometrical parameters of the binary system gliese 150.2

    No full text
    The speckle interferometric binary system Gl 150.2 (HIP17491) is analyzed using atmosphere modeling and dynamical analysis simultaneously. A synthetic spectral energy distribution (SED) for each of the two components of the system is built using Kurucz blanketed models. These SEDs are combined together to form the total flux, which is compared with the observed one in an iterative method to get the best fit. The parameters of the individual components which lead to the best fit are: T eff A = 5350 ± 50 K, T eff B = 4400 ± 50 K, log g A = 4.40 ± 0.05, log g B = 4.68 ± 0.05, R A = 0.95 ± 0.06R ⊙, R B = 0.58 ± 0.06R ⊙, and π = 38.63 ± 0.79 mas, as given by the modified Hipparcos measurement. A modified orbit of the system is introduced and compared with earlier orbits. Hence, the masses of the two components are derived from the coincidence between the atmosphere modeling and dynamical analysis. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, the spectral types and luminosity classes of the two components are found to be G9.5V and K7V for the primary and secondary stars respectively, with an age of about 8 Gyr. Finally, the positions of both components on the H-R diagram are plotted, and the formation and evolution of the system are discussed. © 2014 Pleiades Publishing, Ltd
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