356 research outputs found

    A nuclear factor 1 binding site mediates the transcriptional activation of a type I collagen promoter by transforming growth factor-beta

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    Transforming growth factor-beta (TGF-beta) increases the steady-state RNA levels of several fibroblast extracellular matrix proteins. Using DNA transfection, we show that TGF-beta stimulates the activity of the mouse alpha 2(l) collagen promoter 5- to 10-fold in mouse NIH 3T3 and rat osteosarcoma cells. Deletion analysis indicates that a segment of this promoter between -350 and -300, overlapping a nuclear factor 1 (NF1) binding site, is needed for TGF-beta stimulation. A 3 bp substitution mutation abolishing NF1 binding to this site inhibits TGF-beta activation. Insertion of this NF1 binding site 5' to the SV40 early promoter makes the promoter TGF-beta inducible, but the 3 bp substitution does not. Similarly, when the NF1 binding site at the replication origin of adenovirus 2 and 5 is inserted 5' to the SV40 promoter, the promoter responds to TGF-beta. Therefore an NF1 binding site mediates the transcriptional activation of the mouse alpha 2(l) collagen promoter by TGF-beta

    Pauli equation and the method of supersymmetric factorization

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    We consider different variants of factorization of a 2x2 matrix Schroedinger/Pauli operator in two spatial dimensions. They allow to relate its spectrum to the sum of spectra of two scalar Schroedinger operators, in a manner similar to one-dimensional Darboux transformations. We consider both the case when such factorization is reduced to the ordinary 2-dimensional SUSY QM quasifactorization and a more general case which involves covariant derivatives. The admissible classes of electromagnetic fields are described and some illustrative examples are given.Comment: 18 pages, Late

    The dimerization domain of SOX9 is required for transcription activation of a chondrocyte-specific chromatin DNA template

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    Mutations in SOX9, a gene essential for chondrocyte differentiation cause the human disease campomelic dysplasia (CD). To understand how SOX9 activates transcription, we characterized the DNA binding and cell-free transcription ability of wild-type SOX9 and a dimerization domain SOX9 mutant. Whereas formation of monomeric mutant SOX9–DNA complex increased linearly with increasing SOX9 concentrations, formation of a wild-type SOX9–DNA dimeric complex increased more slowly suggesting a more sigmoidal-type progression. Stability of SOX9–DNA complexes, however, was unaffected by the dimerization mutation. Both wild-type and mutant SOX9 activated transcription of a naked Col2a1 DNA template. However, after nucleosomal assembly, only wild-type and not the mutant was able to remodel chromatin and activate transcription of this template. Using a cell line, in which the Col2a1 vector was stably integrated, no differences were seen in the interactions of wild-type and mutant SOX9 with the chromatin of the Col2a1 vector using ChIP. However, the mutant was unable to activate transcription in agreement with in vitro results. We hypothesize that the SOX9 dimerization domain is necessary to remodel the Col2a1 chromatin in order to allow transcription to take place. These results further clarify the mechanism that accounts for CD in patients harboring SOX9 dimerization domain mutations

    Invariant vector fields and the prolongation method for supersymmetric quantum systems

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    The kinematical and dynamical symmetries of equations describing the time evolution of quantum systems like the supersymmetric harmonic oscillator in one space dimension and the interaction of a non-relativistic spin one-half particle in a constant magnetic field are reviewed from the point of view of the vector field prolongation method. Generators of supersymmetries are then introduced so that we get Lie superalgebras of symmetries and supersymmetries. This approach does not require the introduction of Grassmann valued differential equations but a specific matrix realization and the concept of dynamical symmetry. The Jaynes-Cummings model and supersymmetric generalizations are then studied. We show how it is closely related to the preceding models. Lie algebras of symmetries and supersymmetries are also obtained.Comment: 37 pages, 7 table

    Pentaquark baryons in SU(3) quark model

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    We study the SU(3) group structure of pentaquark baryons which are made of four quarks and one antiquark. The pentaquark baryons form {1}, {8}, {10}, {10}-bar, {27}, and {35} multiplets in SU(3) quark model. First, the flavor wave functions of all the pentaquark baryons are constructed in SU(3) quark model and then the flavor SU(3) symmetry relations for the interactions of the pentaquarks with three-quark baryons and pentaquark baryons are obtained.Comment: REVTeX, 36 pages, 8 figures, references added, section for mass sum rules is added, to appear in Phys. Rev.

    Supersymmetrization of Quaternion Dirac Equation for Generalized Fields of Dyons

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    The quaternion Dirac equation in presence of generalized electromagnetic field has been discussed in terms of two gauge potentials of dyons. Accordingly, the supersymmetry has been established consistently and thereafter the one, two and component Dirac Spinors of generalized quaternion Dirac equation of dyons for various energy and spin values are obtained for different cases in order to understand the duality invariance between the electric and magnetic constituents of dyons.Comment: Key words: Supersymmetry, quaternion, Dirac equation, dyons PACS No.: 11.30.Pb, 14.80.Ly, 03.65.G

    Supersymmetric Homogeneous Quantum Cosmologies Coupled to a Scalar Field

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    Recent work on N=2N=2 supersymmetric Bianchi type IX cosmologies coupled to a scalar field is extended to a general treatment of homogeneous quantum cosmologies with explicitely solvable momentum constraints, i.e. Bianchi types I, II, VII, VIII besides the Bianchi type IX, and special cases, namely the Friedmann universes, the Kantowski-Sachs space, and Taub-NUT space. Besides the earlier explicit solution of the Wheeler DeWitt equation for Bianchi type IX, describing a virtual wormhole fluctuation, an additional explicit solution is given and identified with the `no-boundary state'.Comment: 23 PAGE

    Spin chains from super-models

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    We construct and study a class of N particle supersymmetric Hamiltonians with nearest and next-nearest neighbor inverse-square interaction in one dimension. We show that inhomogeneous XY models in an external non-uniform magnetic field can be obtained from these super-Hamiltonians in a particular limit decoupling the fermionic degrees of freedom from the kinematic ones. We further consider a suitable deformation of these super-models such that inhomogeneous XXZ Hamiltonians in an external non-uniform magnetic field are obtained in the same limit. We show that this deformed Hamiltonian with rational potential is, (i) mapped to a set of free super-oscillators through a similarity transformation and (ii) supersymmetric in terms of a new, non-standard realization of the supercharge. We construct many exact eigenstates of this Hamiltonian and discuss about the applicability of this technique to other models.Comment: 36 pages, RevTeX, No figures, v1; Corrected typos, Added minor clarifications, v2; Added discussions, version to appear in JPSJ, v
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