22 research outputs found

    More on quantum groups from the the quantization point of view

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    Star products on the classical double group of a simple Lie group and on corresponding symplectic grupoids are given so that the quantum double and the "quantized tangent bundle" are obtained in the deformation description. "Complex" quantum groups and bicovariant quantum Lie algebras are discused from this point of view. Further we discuss the quantization of the Poisson structure on symmetric algebra S(g)S(g) leading to the quantized enveloping algebra Uh(g)U_{h}(g) as an example of biquantization in the sense of Turaev. Description of Uh(g)U_{h}(g) in terms of the generators of the bicovariant differential calculus on F(Gq)F(G_q) is very convenient for this purpose. Finally we interpret in the deformation framework some well known properties of compact quantum groups as simple consequences of corresponding properties of classical compact Lie groups. An analogue of the classical Kirillov's universal character formula is given for the unitary irreducible representation in the compact case.Comment: 18 page

    Generalized Integrability and two-dimensional Gravitation

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    We review the construction of generalized integrable hierarchies of partial differential equations, associated to affine Kac-Moody algebras, that include those considered by Drinfel'd and Sokolov. These hierarchies can be used to construct new models of 2D quantum or topological gravity, as well as new W\cal W-algebras.Comment: 24 pages, fixed broken tex sourc

    Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network

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    Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism

    Supplementary Material for: PML-Nuclear Bodies Regulate the Stability of the Fusion Protein Dendra2-Nrf2 in the Nucleus

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    Background/Aims: Nuclear factor erythroid 2-related factor 2 (Nrf2) is a basic leucine-zipper transcription factor essential for cellular responses to oxidative stress. Degradation of Nrf2 in the cytoplasm, mediated by Keap1-Cullin3/RING box1 (Cul3-Rbx1) E3 ubiquitin ligase and the proteasome, is considered the primary pathway controlling the cellular abundance of Nrf2. Although the nucleus has been implicated in the degradation of Nrf2, little information is available on how this compartment participates in degrading Nrf2. Methods: Here, we fused the photoconvertible fluorescent protein Dendra2 to Nrf2 and capitalized on the irreversible change in color (green to red) that occurs when Dendra2 undergoes photoconversion to study degradation of Dendra2-Nrf2 in single live cells. Results: Using this approach, we show that the half-life (t1/2) of Dendra2-Nrf2 in the whole cell, under homeostatic conditions, is 35 min. Inhibition of the proteasome with MG-132 or induction of oxidative stress with tert-butylhydroquinone (tBHQ) extended the half-life of Dendra2-Nrf2 by 6- and 28-fold, respectively. By inhibiting nuclear export using Leptomycin B, we provide direct evidence that degradation of Nrf2 also occurs in the nucleus and involves PML-NBs (Promyelocytic Leukemia-nuclear bodies). We further demonstrate that co-expression of Dendra2-Nrf2 and Crimson-PML-I lacking two PML-I sumoylation sites (K65R and K490R) changed the decay rate of Dendra2-Nrf2 in the nucleus and stabilized the nuclear derived Nrf2 levels in whole cells. Conclusion: Altogether, our findings provide direct evidence for degradation of Nrf2 in the nucleus and suggest that modification of Nrf2 in PML nuclear bodies contributes to its degradation in intact cells

    Automated Enzyme classification by Formal Concept Analysis

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    International audienceEnzymes are molecules with a catalytic activity that make them essential for any biochemical reaction. High throughput genomic technics give access to the protein sequence of new enzymes found in living organisms. Guessing the enzyme functional activity from its sequence is a crucial task that can be approached by comparing the new sequences with those of already known enzymes labeled by a family class. This task is difficult because the activity is based on a combination of small sequence patterns and sequences greatly evolved over time. This paper presents a classifier based on the identification of common subsequence blocks between known and new enzymes and the search of formal concepts built on the cross product of blocks and sequences for each class. Since new enzyme families may emerge, it is important to propose a first classification of enzymes that cannot be assigned to a known family. FCA offer a nice framework to set the task as an optimization problem on the set of concepts. The classifier has been tested with success on a particular set of enzymes present in a large variety of species, the haloacid dehalogenase superfamily
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