Publications by authors named "Amelie Feytout"

8 Publications

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Identifying proteins bound to native mitotic ESC chromosomes reveals chromatin repressors are important for compaction.

Nat Commun 2020 08 17;11(1):4118. Epub 2020 Aug 17.

Lymphocyte Development Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK.

Epigenetic information is transmitted from mother to daughter cells through mitosis. Here, to identify factors that might play a role in conveying epigenetic memory through cell division, we report on the isolation of unfixed, native chromosomes from metaphase-arrested cells using flow cytometry and perform LC-MS/MS to identify chromosome-bound proteins. A quantitative proteomic comparison between metaphase-arrested cell lysates and chromosome-sorted samples reveals a cohort of proteins that were significantly enriched on mitotic ESC chromosomes. These include pluripotency-associated transcription factors, repressive chromatin-modifiers such as PRC2 and DNA methyl-transferases, and proteins governing chromosome architecture. Deletion of PRC2, Dnmt1/3a/3b or Mecp2 in ESCs leads to an increase in the size of individual mitotic chromosomes, consistent with de-condensation. Similar results were obtained by the experimental cleavage of cohesin. Thus, we identify chromosome-bound factors in pluripotent stem cells during mitosis and reveal that PRC2, DNA methylation and Mecp2 are required to maintain chromosome compaction.
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http://dx.doi.org/10.1038/s41467-020-17823-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7431861PMC
August 2020

The CDK Pef1 and protein phosphatase 4 oppose each other for regulating cohesin binding to fission yeast chromosomes.

Elife 2020 01 2;9. Epub 2020 Jan 2.

Institut de Biochimie et Génétique Cellulaires, UMR 5095 CNRS - Université de Bordeaux, Bordeaux, France.

Cohesin has essential roles in chromosome structure, segregation and repair. Cohesin binding to chromosomes is catalyzed by the cohesin loader, Mis4 in fission yeast. How cells fine tune cohesin deposition is largely unknown. Here, we provide evidence that Mis4 activity is regulated by phosphorylation of its cohesin substrate. A genetic screen for negative regulators of Mis4 yielded a CDK called Pef1, whose closest human homologue is CDK5. Inhibition of Pef1 kinase activity rescued cohesin loader deficiencies. In an otherwise wild-type background, Pef1 ablation stimulated cohesin binding to its regular sites along chromosomes while ablating Protein Phosphatase 4 had the opposite effect. Pef1 and PP4 control the phosphorylation state of the cohesin kleisin Rad21. The CDK phosphorylates Rad21 on Threonine 262. Pef1 ablation, non-phosphorylatable Rad21-T262 or mutations within a Rad21 binding domain of Mis4 alleviated the effect of PP4 deficiency. Such a CDK/PP4-based regulation of cohesin loader activity could provide an efficient mechanism for translating cellular cues into a fast and accurate cohesin response.
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http://dx.doi.org/10.7554/eLife.50556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6954021PMC
January 2020

Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults.

Cell Rep 2017 01;18(5):1090-1099

MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK. Electronic address:

Imprinted genes are regulated according to parental origin and can influence embryonic growth and metabolism and confer disease susceptibility. Here, we designed sensitive allele-specific reporters to non-invasively monitor imprinted Cdkn1c expression in mice and showed that expression was modulated by environmental factors encountered in utero. Acute exposure to chromatin-modifying drugs resulted in de-repression of paternally inherited (silent) Cdkn1c alleles in embryos that was temporary and resolved after birth. In contrast, deprivation of maternal dietary protein in utero provoked permanent de-repression of imprinted Cdkn1c expression that was sustained into adulthood and occurred through a folate-dependent mechanism of DNA methylation loss. Given the function of imprinted genes in regulating behavior and metabolic processes in adults, these results establish imprinting deregulation as a credible mechanism linking early-life adversity to later-life outcomes. Furthermore, Cdkn1c-luciferase mice offer non-invasive tools to identify factors that disrupt epigenetic processes and strategies to limit their long-term impact.
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http://dx.doi.org/10.1016/j.celrep.2017.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5300902PMC
January 2017

Jarid2 Coordinates Nanog Expression and PCP/Wnt Signaling Required for Efficient ESC Differentiation and Early Embryo Development.

Cell Rep 2015 Jul 16;12(4):573-86. Epub 2015 Jul 16.

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK. Electronic address:

Jarid2 is part of the Polycomb Repressor complex 2 (PRC2) responsible for genome-wide H3K27me3 deposition. Unlike other PRC2-deficient embryonic stem cells (ESCs), however, Jarid2-deficient ESCs show a severe differentiation block, altered colony morphology, and distinctive patterns of deregulated gene expression. Here, we show that Jarid2(-/-) ESCs express constitutively high levels of Nanog but reduced PCP signaling components Wnt9a, Prickle1, and Fzd2 and lowered β-catenin activity. Depletion of Wnt9a/Prickle1/Fzd2 from wild-type ESCs or overexpression of Nanog largely phenocopies these cellular defects. Co-culture of Jarid2(-/-) with wild-type ESCs restores variable Nanog expression and β-catenin activity and can partially rescue the differentiation block of mutant cells. In addition, we show that ESCs lacking Jarid2 or Wnt9a/Prickle1/Fzd2 or overexpressing Nanog induce multiple ICM formation when injected into normal E3.5 blastocysts. These data describe a previously unrecognized role for Jarid2 in regulating a core pluripotency and Wnt/PCP signaling circuit that is important for ESC differentiation and for pre-implantation development.
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http://dx.doi.org/10.1016/j.celrep.2015.06.060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4534826PMC
July 2015

microRNA-mediated regulation of mTOR complex components facilitates discrimination between activation and anergy in CD4 T cells.

J Exp Med 2014 Oct 13;211(11):2281-95. Epub 2014 Oct 13.

Lymphocyte Development Group and Epigenetics Section, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London W12 0NN, England, UK Lymphocyte Development Group and Epigenetics Section, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London W12 0NN, England, UK

T cell receptor (TCR) signals can elicit full activation with acquisition of effector functions or a state of anergy. Here, we ask whether microRNAs affect the interpretation of TCR signaling. We find that Dicer-deficient CD4 T cells fail to correctly discriminate between activating and anergy-inducing stimuli and produce IL-2 in the absence of co-stimulation. Excess IL-2 production by Dicer-deficient CD4 T cells was sufficient to override anergy induction in WT T cells and to restore inducible Foxp3 expression in Il2-deficient CD4 T cells. Phosphorylation of Akt on S473 and of S6 ribosomal protein was increased and sustained in Dicer-deficient CD4 T cells, indicating elevated mTOR activity. The mTOR components Mtor and Rictor were posttranscriptionally deregulated, and the microRNAs Let-7 and miR-16 targeted the Mtor and Rictor mRNAs. Remarkably, returning Mtor and Rictor to normal levels by deleting one allele of Mtor and one allele of Rictor was sufficient to reduce Akt S473 phosphorylation and to reduce co-stimulation-independent IL-2 production in Dicer-deficient CD4 T cells. These results show that microRNAs regulate the expression of mTOR components in T cells, and that this regulation is critical for the modulation of mTOR activity. Hence, microRNAs contribute to the discrimination between T cell activation and anergy.
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http://dx.doi.org/10.1084/jem.20132059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4203951PMC
October 2014

Different roles for Tet1 and Tet2 proteins in reprogramming-mediated erasure of imprints induced by EGC fusion.

Mol Cell 2013 Mar 28;49(6):1023-33. Epub 2013 Feb 28.

Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.

Genomic imprinting directs the allele-specific marking and expression of loci according to their parental origin. Differential DNA methylation at imprinted control regions (ICRs) is established in gametes and, although largely preserved through development, can be experimentally reset by fusing somatic cells with embryonic germ cell (EGC) lines. Here, we show that the Ten-Eleven Translocation proteins Tet1 and Tet2 participate in the efficient erasure of imprints in this model system. The fusion of B cells with EGCs initiates pluripotent reprogramming, in which rapid re-expression of Oct4 is accompanied by an accumulation of 5-hydroxymethylcytosine (5hmC) at several ICRs. Tet2 was required for the efficient reprogramming capacity of EGCs, whereas Tet1 was necessary to induce 5-methylcytosine oxidation specifically at ICRs. These data show that the Tet1 and Tet2 proteins have discrete roles in cell-fusion-mediated pluripotent reprogramming and imprint erasure in somatic cells.
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http://dx.doi.org/10.1016/j.molcel.2013.01.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3613797PMC
March 2013

Pds5 promotes cohesin acetylation and stable cohesin-chromosome interaction.

EMBO Rep 2012 Jun 29;13(7):645-52. Epub 2012 Jun 29.

University Bordeaux, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France.

Pds5 and Wpl1 act as anti-establishment factors preventing sister-chromatid cohesion until counteracted in S-phase by the cohesin acetyl-transferase Eso1. However, Pds5 is also required to maintain sister-chromatid cohesion in G2. Here, we show that Pds5 is essential for cohesin acetylation by Eso1 and ensures the maintenance of cohesion by promoting a stable cohesin interaction with replicated chromosomes. The latter requires Eso1 only in the presence of Wapl, indicating that cohesin stabilization relies on Eso1 only to neutralize the anti-establishment activity. We suggest that Eso1 requires Pds5 to counteract anti-establishment. This allows both cohesion establishment and Pds5-dependent stable cohesin binding to chromosomes.
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http://dx.doi.org/10.1038/embor.2012.72DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3388792PMC
June 2012

Psm3 acetylation on conserved lysine residues is dispensable for viability in fission yeast but contributes to Eso1-mediated sister chromatid cohesion by antagonizing Wpl1.

Mol Cell Biol 2011 Apr 7;31(8):1771-86. Epub 2011 Feb 7.

Institut de Biochimie et Génétique Cellulaires CNRS UMR 5095, 1 rue Camille Saint Saëns, Bordeaux F-33077, France.

In budding yeast and humans, cohesion establishment during S phase requires the acetyltransferase Eco1/Esco1-2, which acetylates the cohesin subunit Smc3 on two conserved lysine residues. Whether Smc3 is the sole Eco1/Esco1-2 effector and how Smc3 acetylation promotes cohesion are unknown. In fission yeast (Schizosaccharomyces pombe), as in humans, cohesin binding to G(1) chromosomes is dynamic and the unloading reaction is stimulated by Wpl1 (human ortholog, Wapl). During S phase, a subpopulation of cohesin becomes stably bound to chromatin in an Eso1 (fission yeast Eco1/Esco1-2)-dependent manner. Cohesin stabilization occurs unevenly along chromosomes. Cohesin remains largely labile at the rDNA repeats but binds mostly in the stable mode to pericentromere regions. This pattern is largely unchanged in eso1Δ wpl1Δ cells, and cohesion is unaffected, indicating that the main Eso1 role is counteracting Wpl1. A mutant of Psm3 (fission yeast Smc3) that mimics its acetylated state renders cohesin less sensitive to Wpl1-dependent unloading and partially bypasses the Eso1 requirement but cannot generate the stable mode of cohesin binding in the absence of Eso1. Conversely, nonacetylatable Psm3 reduces the stable cohesin fraction and affects cohesion in a Wpl1-dependent manner, but cells are viable. We propose that Psm3 acetylation contributes to Eso1 counteracting of Wpl1 to secure stable cohesin interaction with postreplicative chromosomes but that it is not the sole molecular event by which this occurs.
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http://dx.doi.org/10.1128/MCB.01284-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126331PMC
April 2011