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Search Results: 1 - 10 of 73 matches for " Nowel Azzouz "
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The CCR4-NOT Complex Physically and Functionally Interacts with TRAMP and the Nuclear Exosome
Nowel Azzouz, Olesya O. Panasenko, Geoffroy Colau, Martine A. Collart
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006760
Abstract: Background Ccr4-Not is a highly conserved multi-protein complex consisting in yeast of 9 subunits, including Not5 and the major yeast deadenylase Ccr4. It has been connected functionally in the nucleus to transcription by RNA polymerase II and in the cytoplasm to mRNA degradation. However, there has been no evidence so far that this complex is important for RNA degradation in the nucleus. Methodology/Principal Findings In this work we point to a new role for the Ccr4-Not complex in nuclear RNA metabolism. We determine the importance of the Ccr4-Not complex for the levels of non-coding nuclear RNAs, such as mis-processed and polyadenylated snoRNAs, whose turnover depends upon the nuclear exosome and TRAMP. Consistently, mutation of both the Ccr4-Not complex and the nuclear exosome results in synthetic slow growth phenotypes. We demonstrate physical interactions between the Ccr4-Not complex and the exosome. First, Not5 co-purifies with the exosome. Second, several exosome subunits co-purify with the Ccr4-Not complex. Third, the Ccr4-Not complex is important for the integrity of large exosome-containing complexes. Finally, we reveal a connection between the Ccr4-Not complex and TRAMP through the association of the Mtr4 helicase with the Ccr4-Not complex and the importance of specific subunits of Ccr4-Not for the association of Mtr4 with the nuclear exosome subunit Rrp6. Conclusions/Significance We propose a model in which the Ccr4-Not complex may provide a platform contributing to dynamic interactions between the nuclear exosome and its co-factor TRAMP. Our findings connect for the first time the different players involved in nuclear and cytoplasmic RNA degradation.
The Ccr4-Not Complex Interacts with the mRNA Export Machinery
Shana C. Kerr,Nowel Azzouz,Stephen M. Fuchs,Martine A. Collart,Brian D. Strahl,Anita H. Corbett,R. Nicholas Laribee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018302
Abstract: The Ccr4-Not complex is a key eukaryotic regulator of gene transcription and cytoplasmic mRNA degradation. Whether this complex also affects aspects of post-transcriptional gene regulation, such as mRNA export, remains largely unexplored. Human Caf1 (hCaf1), a Ccr4-Not complex member, interacts with and regulates the arginine methyltransferase PRMT1, whose targets include RNA binding proteins involved in mRNA export. However, the functional significance of this regulation is poorly understood.
On the number of branches of real curve singularities
Aleksandra Nowel,Zbigniew Szafraniec
Mathematics , 2010, DOI: 10.1112/blms/bdr040
Abstract: There is presented a method for computing the number of branches of a real analytic curve germ from $R^n$ to $R^m$, where m is greater or equal to n, having a singular point at the origin, and the number of half--branches of the set of double points of an analytic germ from $R^2$ to $R^3$.
Fermi Surface Reconstruction due to Hidden Rotating Antiferromagnetism in N and P-Type High-TC Cuprates
Mohamed Azzouz
Symmetry , 2013, DOI: 10.3390/sym5020215
Abstract: The Fermi surface calculated within the rotating antiferromagnetism theory undergoes a topological change when doping changes from p-type to n-type, in qualitative agreement with experimental data for n-type cuprate Nd2?xCexCuO4 and p-type La2?xSrxCuO4. Also, the reconstruction of the Fermi surface, observed experimentally close to optimal doping in p-type cuprates, and slightly higher than optimal doping in the overdoped regime for this n-type high-TC cuprate, is well accounted for in this theory. This reconstruction is a consequence of the quantum criticality caused by the disappearance of rotating antiferromagnetism. The present results are in qualitative agreement with recently observed quantum oscillations in some high-TC cuprates. This paper presents new results about the application of the rotating antiferromagnetism theory to the study of the electronic structure for n-type materials.
Calculation of the phase of hidden rotating antiferromagnetic order
M. Azzouz
Physics , 2012, DOI: 10.1016/j.physc.2012.05.010
Abstract: The phase of the rotating order parameter in rotating antiferromagnetism is calculated using a combination of mean-field theory and Heisenberg equation. This phase shows a linear time dependence, which allows us to interpret rotating antiferromagnetism as a synchronized Larmor-like precession of all the spins in the system or as an unusual ${\bf q}=(\pi,\pi)$ spin-wave around a zero local magnetization. We discuss implications for the pseudogap state of high-$T_C$ superconducting materials. Rotating antiferromagnetism has been proposed to model the pseudogap state in these materials.
Identification of the physical parameters of the paramagnetic phase of the one-dimensional Kondo lattice model done by introducting a nonmagnetic quantum state with rotating order parameters
M. Azzouz
Physics , 2000, DOI: 10.1103/PhysRevB.62.710
Abstract: The paramagnetic phase of the one-dimensional Kondo lattice model is investigated for electron densities below half-filling using a new mean-field approach. The physical parameters that govern this phase are identified to be the spin-flip processes of both the localized and itinerant spins. A nonmagnetic quantum state, where the local magnetization is a rotating vector with a nonzero average length, is proposed in order to describe this phase. This state does not break SU(2) symmetry in agreement with Mermin-Wagner theorem. The line boundary between this phase and the ferromagnetic phase is calculated in the coupling-density phase diagram. Also, expressions are calculated for the velocities of the conduction electrons excitations, and heat capacity and entropy versus temperature are analyzed. Good agreement with many of the available numerical data is achieved.
Theory of the Magnetic Resonance for the High-$T_C$ Copper-Oxide Superconductors
Mohamed Azzouz
Physics , 2014, DOI: 10.1016/j.physc.2014.11.001
Abstract: The magnetic response expected from a state characterized by rotating antiferromagnetism in a neutron-scattering experiment is calculated. We predict the occurrence of a peak at the frequency of the rotation of the rotating antiferromagnetic order parameter. The doping dependence of this frequency is very similar to that of the frequency of the magnetic resonance observed in the neutron-scattering experiments for the hole-doped high-$T_C$ cuprates. This leads us to propose the rotating antiferromagnetism as a possible mechanism for this magnetic resonance. We conclude that while the magnitude of the rotating antiferromagnetic order parameter was previously proposed to be responsible for the pseudogap and the unusual thermodynamic and transport properties, the phase of the rotating order parameter is proposed here to be responsible for the unusual magnetic properties of the high-$T_C$ copper-oxide superconductors.
Fermi surface reconstruction due to hidden rotating antiferromagnetism in n and p-type high-$T_C$ cuprates
M. Azzouz
Physics , 2012,
Abstract: The Fermi surface calculated within the rotating antiferromagentism theory undergoes a topological change when doping changes from p-type to n-type, in qualitative agreement with experimental data for n-type cuprate Nd$_{2-x}$Ce$_x$CuO$_4$ and p-type La$_{2-x}$Sr$_x$CuO$_4$. Also, the reconstruction of the Fermi surface observed experimentally close to optimal doing in p-type cuprates, and slightly higher than optimal doping in the overdoped regime for this n-type high-$T_C$ cuprate is well accounted for in this theory, and is a consequence of quantum criticality caused by the disappearance of rotating antiferromagnetism. The present results are in qualitative agreement with the recently observed quantum oscillations in some high-$T_C$ cuprates regarding the change in the size of the Fermi surface as doping evolves and the location of its reconstruction. This paper presents new results about the application of the rotating antiferromagnetism theory to the study of electronic structure for n-type materials.
Variétés de Poisson polarisées
Azzouz Awane
Mathematics , 2003,
Abstract: We introduce and study the basic notion of polarized Poisson manifolds generalizing the classical case of Poisson manifolds and extend this last notion for the ${k-}$% symplectic stuctures. And also, we show that for any polarized Hamiltonian map, the associated Nambu's dynamical system and polarized Hamiltonian system are connected by relations characterizing the mechanical aspect of the $k-$symplectic geometry.
Ternary algebras with braided statistics
Azzouz Zinoun
Mathematics , 2010,
Abstract: Algebraic relations that characterize quantum statistics (Bose-Einstein statistic, Fermi-Dirac statistic, supersymmetry, parastatistic, anyonic statistic, ...) are reformulated herein in terms of a new algebraic structure, which we call para-algebra.
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