Nuclear mRNA Degradation Pathway(s) Are Implicated in Xist Regulation and X Chromosome Inactivation

A critical step in X-chromosome inactivation (XCI), which results in the dosage compensation of X-linked gene expression in mammals, is the coating of the presumptive inactive X chromosome by the large noncoding Xist RNA, which then leads to the recruitment of other factors essential for the heterochromatinisation of the inactive X and its transcriptional silencing. In an approach aimed at identifying genes implicated in the X-inactivation process by comparative transcriptional profiling of female and male mouse gastrula, we identified the Eif1 gene involved in translation initiation and RNA degradation. We show here that female embryonic stem cell lines, silenced by RNA interference for the Eif1 gene, are unable to form Xist RNA domains upon differentiation and fail to undergo X-inactivation. To probe further an effect involving RNA degradation pathways, the inhibition by RNA interference of Rent1, a factor essential for nonsense-mediated decay and Exosc10, a specific nuclear component of the exosome, was analysed and shown to similarly impair Xist upregulation and XCI. In Eif1-, Rent1-, and Exosc10-interfered clones, Xist spliced form(s) are strongly downregulated, while the levels of unspliced form(s) of Xist and the stability of Xist RNA remain comparable to that of the control cell lines. Our data suggests a role for mRNA nuclear degradation pathways in the critical regulation of spliced Xist mRNA levels and the onset of the X-inactivation process

Monitoring immune modulation by nutrition in the general population: identifying and substantiating effects on human health

Optimal functioning of the immune system is crucial to human health, and nutrition is one of the major exogenous factors modulating different aspects of immune function. Currently, no single marker is available to predict the effect of a dietary intervention on different aspects of immune function. To provide further guidance on the assessment and interpretation of the modulation of immune functions due to nutrition in the general population, International Life Sciences Institute Europe commissioned a group of experts from academia, government and the food industry to prepare a guidance document. A draft of this paper was refined at a workshop involving additional experts. First, the expert group defined criteria to evaluate the usefulness of immune function markers. Over seventy-five markers were scored within the context of three distinct immune system functions: defence against pathogens; avoidance or mitigation of allergy; control of low-grade (metabolic) inflammation. The most useful markers were subsequently classified depending on whether they by themselves signify clinical relevance and/or involvement of immune function. Next, five theoretical scenarios were drafted describing potential changes in the values of markers compared with a relevant reference range. Finally, all elements were combined, providing a framework to aid the design and interpretation of studies assessing the effects of nutrition on immune function. This stepwise approach offers a clear rationale for selecting markers for future trials and provides a framework for the interpretation of outcomes. A similar stepwise approach may also be useful to rationalise the selection and interpretation of markers for other physiological processes critical to the maintenance of health and well-bein

Recherche de nouveaux acteurs impliqués dans l' inactivation du chromosome X (étude des transcriptomes d' embryons murins précoces mâles et femelles)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Instrumentation du tuteur distant, par l'intermédiaire d'une typologie théorique des habiletés cognitives, afin d'identifier les stratégies cognitives de l'apprenant singulier d'un niveau A2 de français langue étrangère en compréhension écrite au sein d'un dispositif hybride de formation

Etant donné que dans les environnements universitaires d enseignement et d apprentissage à distance, le tuteur, dans son activité de perception, a des difficultés à détecter les stratégies cognitives à l origine d un blocage, ce qui nécessite une instrumentation spécifique pour visualiser l activité cognitive de l apprenant dans son parcours d apprentissage médiatisé, notre problématique de recherche a pour finalité d instrumenter le tuteur distant pour que cet acteur, d une formation hybride sur la plateforme UMTICE, puisse identifier les stratégies cognitives en compréhension écrite de l apprenant singulier de FLE. Cette problématique de recherche donne lieu à deux hypothèses de recherche visant pour la première la conception d'une typologie théorique des habiletés cognitives afin de nommer les stratégies cognitives que pourrait utiliser cet apprenant lors de la réalisation de tâches de compréhension écrite et pour la seconde à nuancer l'emploi de notre instrument par le tuteur distant dans sa fonction d'identification perceptivo-cognitive lors de l'expérimentation qui s'est déroulée dans un cours particulier du CIEF de l'Université Lumière Lyon 2.A Given that in his perception activities in university Online teaching and learning environments, the tutor has difficulty in detecting cognitive strategies that cause a blockage and which requires specific instrumentation for visualize the cognitive activity of the learner in his mediated learning path, our research objective is to instrument an On-line tutor for this actor with hybrid training on the UMTICE platform that can identify the cognitive strategies in the individual French as Foreign Language learner s written comprehension. This research problem gives rise to two research hypotheses, first for the design of a theoretical typology of cognitive abilities in order to name the cognitive strategies that this learner could use when performing written comprehension tasks, and second to qualify the use of our tool by the On-line tutor in his perceptual cognitive identification function during the experiment that took place in a particular course at the CIEF of University Lumière Lyon 2.LE MANS-BU Lettres (721812108) / SudocSudocFranceF

Transient Interference of <i>Eif1, Upf3A,</i> and <i>Upf3B</i>

<div><p>Quantification of <i>Eif1</i> (A), <i>Upf3A</i> (B), <i>Upf3B</i> (C), and <i>Xist</i> (D) RNAs using Eif1Up/Lo, Upf3AUp/Lo, Upf3BUp/Lo, and Xist exon1–exon3 primers, respectively, after 48 h of interference using siRNA siGL3, siEif1, siUpf3A, and siUpf3B.</p><p>Columns and bars are constructed as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0020094#pgen-0020094-g001" target="_blank">Figure 1</a>.</p></div

Overexpression of <i>Xist</i> cDNA Transgene and Impact of Interference on ncRNAs and Imprinted RNAs

<div><p>(A–B) Quantification of <i>Xist</i> and <i>Tsix</i> RNAs using Xist exon1–exon3 and Tsix using exon2–exon3 primers in the parental female ES cell line (LF2) and knocked down clones for <i>Eif1</i> (E1), <i>Rent1</i> (R1), and <i>Exosc10</i> (Ex1), and in the same cells 48 h after transfection with <i>Xist</i> cDNA transgene. Quantification of <i>His1</i> (C), <i>Bc1</i> (D), <i>Ube3A</i> (E), <i>Peg3</i> (F), and <i>H19</i> (G) RNAs using His1Up/Lo, Bc11Up/Lo, Ube3AUp/Lo, Peg3Up/Lo, and H19Up/Lo primers respectively, at d 0 and d 4 of retinoic acid–induced ES cell differentiation.</p><p>Columns and bars are constructed as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0020094#pgen-0020094-g001" target="_blank">Figure 1</a>.</p></div

The <i>Eif1</i>, <i>Rent1,</i> and <i>Exosc10</i> Genes Are Essential for the Upregulation of <i>Xist</i> mRNA During Differentiation

<div><p>(A) Quantification of <i>Eif1, Rent1, Exosc10,</i> and <i>Rasa1</i> RNAs using Eif1Up/Lo, Rent1Up/Lo, Exosc10Up/Lo, and Rasa1Up/Lo primers, respectively, at d 0 and d 4 of retinoic acid–induced ES cell differentiation. LF2 is the parental female ES cell line. The T1 clone is a control generated by integration of an empty pSuper-puro vector into the LF2 cell line. The E1 and E2 clones were generated by integration of a pSuper-puro vector containing a hairpin designed against the ORF of the <i>Eif1</i> gene. The R1 and R2 clones were generated by integrating a pSuper-puro vector containing hairpins 1 and 2, respectively, directed against the ORF of <i>Rent1</i> gene. The Ex1 and Ex2 clones were generated by integrating a pSuper-puro vector containing hairpins 1 and 2, respectively, directed against the ORF of the <i>Exosc10</i> gene. The Ra1 and Ra2 clones were generated using the plasmid previously described by Rossant and colleagues [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0020094#pgen-0020094-b033" target="_blank">33</a>] that contains a hairpin directed against the <i>Rasa1</i> gene.</p><p>(B) Quantification, using exon1–exon3 primers, of spliced <i>Xist</i> RNAs at d 0 and d 4 of differentiation, in the parental female ES cell line (LF2), the T1 control clone, and clones interfered for <i>Eif1</i> (E1 and E2), <i>Rent1</i> (R1 and R2), <i>Exosc10</i> (Ex1 and Ex2), and <i>Rasa1</i> (Ra1 and Ra2).</p><p>Columns and bars show the mean ± standard deviation (SD) (n = 3), expressed in arbitrary units, of the quantity of <i>Eif1, Rent1, Exosc10, Rasa1,</i> and <i>Xist</i> transcript standardized over <i>Rrm2</i> RNA.</p></div