55 research outputs found

    Analisis Kemampuan Berpikir Kreatif Peserta Didik SMP dalam Menyelesaikan Permasalahan Aljabar di Era Pandemi

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    The purpose of this research is to analyze the mathematical creativity skills of junior high school students in solving algebra cases during the pandemic. The research method used is descriptive qualitative. The subjects of this study were 33 students in class VII B at 253 State Junior High School in Jakarta. The research technique used a descriptive mathematical creative thinking test instrument on algebraic material and carried out interviews with 3 screened students who were randomly selected according to their level of creative thinking. In this study, there are four indicators of mathematical creative thinking, namely fluency, flexibility, originality, and elaboration. The results of this study revealed 14 students who have low mathematical creative thinking skills, 11 students who have moderate mathematical creative thinking abilities, and 8 students who have high mathematical creative thinking abilitie

    EyeSat: A Great Student Adventure Within the French Space Agency Leading Up to Lessons Learned From Orbit

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    EyeSat has been a tremendous, challenging and successful student project. With 250 students over 7 years, CNES has achieved to put in orbit a 3U CubeSat that carries tens of state-of-the art innovative nanosatellite subsystems resulting from R&D programs carried out within the French space ecosystem. Launched in December 18, 2019, EyeSat has proved to be fully functional in orbit and has started its mission to map the intensity and the polarization direction of the zodiacal light. Housekeeping data, acquired over the past 5 months, has been analyzed by the team. Precious comparisons have been made between design and simulation results on the one hand and actual data on the other. Now, the private company U-Space, created in 2018, leverages those lessons learned from EyeSat and provides space missions based on high-performance nanosatellites

    The DDX6-4E-T interaction mediates translational repression and P-body assembly

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    This is the final version of the article. Available from the publisher via the DOI in this record.4E-Transporter binds eIF4E via its consensus sequence YXXXXLΊ, shared with eIF4G, and is a nucleocytoplasmic shuttling protein found enriched in P-(rocessing) bodies. 4E-T inhibits general protein synthesis by reducing available eIF4E levels. Recently, we showed that 4E-T bound to mRNA however represses its translation in an eIF4E-independent manner, and contributes to silencing of mRNAs targeted by miRNAs. Here, we address further the mechanism of translational repression by 4E-T by first identifying and delineating the interacting sites of its major partners by mass spectrometry and western blotting, including DDX6, UNR, unrip, PAT1B, LSM14A and CNOT4. Furthermore, we document novel binding between 4E-T partners including UNR-CNOT4 and unrip-LSM14A, altogether suggesting 4E-T nucleates a complex network of RNA-binding protein interactions. In functional assays, we demonstrate that joint deletion of two short conserved motifs that bind UNR and DDX6 relieves repression of 4E-T-bound mRNA, in part reliant on the 4E-T-DDX6-CNOT1 axis. We also show that the DDX6-4E-T interaction mediates miRNA-dependent translational repression and de novo P-body assembly, implying that translational repression and formation of new P-bodies are coupled processes. Altogether these findings considerably extend our understanding of the role of 4E-T in gene regulation, important in development and neurogenesis.BBSRC [BB/J00779X/1 to N.S.]; CNRS PICS (to D.W.); Agence Nationale pour la Recherche [ANR-14-CE09-0013-01ANR to D.W.]; Gates Cambridge Foundation (to A.K.); Fondation Wiener – Anspach of the UniversitĂ© Libre de Bruxelles and the Cambridge Newton Trust (C.V.). Funding for open access charge: BBSRC

    The DDX6-4E-T interaction mediates translational repression and P-body assembly.

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    4E-Transporter binds eIF4E via its consensus sequence YXXXXLΊ, shared with eIF4G, and is a nucleocytoplasmic shuttling protein found enriched in P-(rocessing) bodies. 4E-T inhibits general protein synthesis by reducing available eIF4E levels. Recently, we showed that 4E-T bound to mRNA however represses its translation in an eIF4E-independent manner, and contributes to silencing of mRNAs targeted by miRNAs. Here, we address further the mechanism of translational repression by 4E-T by first identifying and delineating the interacting sites of its major partners by mass spectrometry and western blotting, including DDX6, UNR, unrip, PAT1B, LSM14A and CNOT4. Furthermore, we document novel binding between 4E-T partners including UNR-CNOT4 and unrip-LSM14A, altogether suggesting 4E-T nucleates a complex network of RNA-binding protein interactions. In functional assays, we demonstrate that joint deletion of two short conserved motifs that bind UNR and DDX6 relieves repression of 4E-T-bound mRNA, in part reliant on the 4E-T-DDX6-CNOT1 axis. We also show that the DDX6-4E-T interaction mediates miRNA-dependent translational repression and de novo P-body assembly, implying that translational repression and formation of new P-bodies are coupled processes. Altogether these findings considerably extend our understanding of the role of 4E-T in gene regulation, important in development and neurogenesis.BBSRC [BB/J00779X/1 to N.S.]; CNRS PICS (to D.W.); Agence Nationale pour la Recherche [ANR-14-CE09-0013-01ANR to D.W.]; Gates Cambridge Foundation (to A.K.); Fondation Wiener – Anspach of the UniversitĂ© Libre de Bruxelles and the Cambridge Newton Trust (C.V.). Funding for open access charge: BBSRC

    GC content shapes mRNA storage and decay in human cells.

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    mRNA translation and decay appear often intimately linked although the rules of this interplay are poorly understood. In this study, we combined our recent P-body transcriptome with transcriptomes obtained following silencing of broadly acting mRNA decay and repression factors, and with available CLIP and related data. This revealed the central role of GC content in mRNA fate, in terms of P-body localization, mRNA translation and mRNA stability: P-bodies contain mostly AU-rich mRNAs, which have a particular codon usage associated with a low protein yield; AU-rich and GC-rich transcripts tend to follow distinct decay pathways; and the targets of sequence-specific RBPs and miRNAs are also biased in terms of GC content. Altogether, these results suggest an integrated view of post-transcriptional control in human cells where most translation regulation is dedicated to inefficiently translated AU-rich mRNAs, whereas control at the level of 5' decay applies to optimally translated GC-rich mRNAs

    Dual RNA processing roles of Pat1b via cytoplasmic Lsm1-7 and nuclear Lsm2-8 complexes

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    Pat1 RNA-binding proteins, enriched in P-bodies, are key players in cytoplasmic 5’ to 3’ mRNA decay, activating decapping of mRNA in complex with the Lsm1-7 heptamer. Using co-immunoprecipitation and immunofluorescence approaches coupled with RNAi, we provide evidence for a nuclear complex of Pat1b with the Lsm2-8 heptamer, which binds to the spliceosomal U6 snRNA. Furthermore, we establish the set of interactions connecting Pat1b/Lsm2-8/U6 snRNA/SART3 and additional U4/U6.U5 tri-snRNP components, in Cajal bodies, the site of snRNP biogenesis. RNAseq following Pat1b depletion revealed the preferential up-regulation of mRNAs normally found in P-bodies and enriched in 3’ UTR AU-rich elements. Changes in >180 alternative splicing events were also observed, characterized by skipping of regulated exons with weak donor sites. Our data demonstrate the unsuspected dual role of a decapping enhancer in pre-mRNA processing as well as in mRNA decay via distinct nuclear and cytoplasmic Lsm complexes.This work was funded by a fellowship to CV from the Fondation Wiener – Anspach, BBSRC (BB/J00779X/1) and the Newton Trust (University of Cambridge) to NS, and CNRS PICS and ANR (14- CE09-0013-01ANR) to DW. The CMMI is supported by the European Regional Development Fund and the Walloon Region

    Dual RNA processing roles of Pat1b via cytoplasmic Lsm1-7 and nuclear Lsm2-8 complexes

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    Pat1 RNA-binding proteins, enriched in P-bodies, are key players in cytoplasmic 5’ to 3’ mRNA decay, activating decapping of mRNA in complex with the Lsm1-7 heptamer. Using co-immunoprecipitation and immunofluorescence approaches coupled with RNAi, we provide evidence for a nuclear complex of Pat1b with the Lsm2-8 heptamer, which binds to the spliceosomal U6 snRNA. Furthermore, we establish the set of interactions connecting Pat1b/Lsm2-8/U6 snRNA/SART3 and additional U4/U6.U5 tri-snRNP components, in Cajal bodies, the site of snRNP biogenesis. RNAseq following Pat1b depletion revealed the preferential up-regulation of mRNAs normally found in P-bodies and enriched in 3’ UTR AU-rich elements. Changes in >180 alternative splicing events were also observed, characterized by skipping of regulated exons with weak donor sites. Our data demonstrate the unsuspected dual role of a decapping enhancer in pre-mRNA processing as well as in mRNA decay via distinct nuclear and cytoplasmic Lsm complexes.This work was funded by a fellowship to CV from the Fondation Wiener – Anspach, BBSRC (BB/J00779X/1) and the Newton Trust (University of Cambridge) to NS, and CNRS PICS and ANR (14- CE09-0013-01ANR) to DW. The CMMI is supported by the European Regional Development Fund and the Walloon Region

    Aujourd'hui le Moyen Age, archéologie et vie quotidienne en France Méridionale

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    [catalogue d'exposition], 1981-1983, SĂ©nanque, Marseille, Arles, Toulon, Perpignan, Montpellier, Nice, GapInternational audienceCe catalogue d’exposition itinĂ©rante, fait la synthĂšse des principaux travaux du Laboratoire d’ArchĂ©ologie MĂ©diĂ©vale MĂ©diterranĂ©enne d’Aix-en-Provence (URA 6 du CRA CNRS) en 1981 rĂ©unis par l’équipe de Gabrielle DĂ©mians d’Archimbaud. L’habitat, les gestes de la vie quotidienne, le commerce et l’artisanat sont illustrĂ©s par les fouilles effectuĂ©es dans le Midi de la France, par de nombreux objets, en cĂ©ramique, verre, pierre, os et mĂ©tal ainsi que par les sources Ă©crites, et les analyses de laboratoire, innovantes Ă  cette Ă©poque

    Regulation of cytoplasmic RNA stability: lessons from drosophila

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    The process of RNA degradation is a critical level of regulation contributing to the control of gene expression. In the last two decades a number of studies have shown the specific and targeted nature of RNA decay and its importance in maintaining homeostasis. The key players within the pathways of RNA decay are well conserved with their mutation or disruption resulting in distinct phenotypes as well as human disease. Model organisms including Drosophila melanogaster have played a substantial role in elucidating the mechanisms conferring control over RNA stability. A particular advantage of this model organism is that the functions of ribonucleases can be assessed in the context of natural cells within tissues in addition to individual immortalised cells in culture. Drosophila RNA stability research has demonstrated how the cytoplasmic decay machines, such as the exosome, Dis3L2 and Xrn1, are responsible for regulating specific processes including apoptosis, proliferation, wound healing and fertility. The work discussed here has begun to identify specific mRNA transcripts that appear sensitive to specific decay pathways representing mechanisms through which the ribonucleases control mRNA stability. Drosophila research has also contributed to our knowledge of how specific RNAs are targeted to the ribonucleases including AU rich elements, miRNA targeting and 3’ tailing. Increased understanding of these mechanisms is critical to elucidating the control elicited by the cytoplasmic ribonucleases which is relevant to human disease

    The Lsm1-7/Pat1 complex binds to stress-activated mRNAs and modulates the response to hyperosmotic shock

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    RNA-binding proteins (RBPs) establish the cellular fate of a transcript, but an understanding of these processes has been limited by a lack of identified specific interactions between RNA and protein molecules. Using MS2 RNA tagging, we have purified proteins associated with individual mRNA species induced by osmotic stress, STL1 and GPD1. We found members of the Lsm1-7/Pat1 RBP complex to preferentially bind these mRNAs, relative to the non-stress induced mRNAs, HYP2 and ASH1. To assess the functional importance, we mutated components of the Lsm1-7/Pat1 RBP complex and analyzed the impact on expression of osmostress gene products. We observed a defect in global translation inhibition under osmotic stress in pat1 and lsm1 mutants, which correlated with an abnormally high association of both non-stress and stress-induced mRNAs to translationally active polysomes. Additionally, for stress-induced proteins normally triggered only by moderate or high osmostress, in the mutants the protein levels rose high already at weak hyperosmosis. Analysis of ribosome passage on mRNAs through co-translational decay from the 5' end (5P-Seq) showed increased ribosome accumulation in lsm1 and pat1 mutants upstream of the start codon. This effect was particularly strong for mRNAs induced under osmostress. Thus, our results indicate that, in addition to its role in degradation, the Lsm1-7/Pat1 complex acts as a selective translational repressor, having stronger effect over the translation initiation of heavily expressed mRNAs. Binding of the Lsm1-7/Pat1p complex to osmostress-induced mRNAs mitigates their translation, suppressing it in conditions of weak or no stress, and avoiding a hyperresponse when triggered
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