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Monterotondo Marittimo, Italy

Pintacuda G.,University of Oxford | Cerase A.,EMBL Mouse Biology Unit
Stem Cell Reviews and Reports

X chromosome inactivation (XCI) is the dosage compensation mechanism that evolved in female mammals to correct the genetic imbalance of X-linked genes between sexes. X chromosome inactivation occurs in early development when one of the two X chromosomes of females is nearly-completely silenced. Differentiating Embryonic Stem cells (ESC) are regarded as a useful tool to study XCI, since they recapitulate many events occurring during early development. In this review we aim to summarise the advances in the field and to discuss the close connection between cell differentiation and X chromosome inactivation, with a particular focus on mouse ESCs. © 2015, The Author(s). Source

S.B.C. B.,EMBL Mouse Biology Unit
Experimental Cell Research

Constitutive heterochromatin is essential for chromosome maintenance in all eukaryotes. However, the repetitive nature of the underlying DNA, the presence of very stable protein-DNA complexes and the highly compacted nature of this type of chromatin represent a challenge for the DNA replication machinery. Data collected from different model organisms suggest that at least some of the components of the DNA replication checkpoint could be essential for ensuring the completion of DNA replication in the context of heterochromatin. I review and discuss the literature that directly or indirectly contributes to the formulation of this hypothesis. In particular, I focus my attention on Rif1, a newly discovered member of the DNA replication checkpoint. Recent data generated in mammalian cells highlight the spatial and temporal relation between Rif1, pericentromeric heterochromatin and S-phase. I review these recent and the previous data coming from studies performed in yeast in order to highlight the possible evolutionary conserved links and propose a molecular model for Rif1 role in heterochromatin replication. © 2010 Elsevier Inc. Source

Becker S.,Robert Bosch GmbH | Becker S.,University of Tubingen | Oelschlaeger T.A.,University of Wurzburg | Wullaert A.,University of Cologne | And 7 more authors.

Background: The human colon harbours a plethora of bacteria known to broadly impact on mucosal metabolism and function and thought to be involved in inflammatory bowel disease pathogenesis and colon cancer development. In this report, we investigated the effect of colonic bacteria on epithelial cell differentiation factors in vitro and in vivo. As key transcription factors we focused on Hes1, known to direct towards an absorptive cell fate, Hath1 and KLF4, which govern goblet cell. Methods: Expression of the transcription factors Hes1, Hath1 and KLF4, the mucins Muc1 and Muc2 and the defensin HBD2 were measured by real-time PCR in LS174T cells following incubation with several heat-inactivated E. coli strains, including the probiotic E. coli Nissle 1917+/- flagellin, Lactobacilli and Bifidobacteria. For protein detection Western blot experiments and chamber-slide immunostaining were performed. Finally, mRNA and protein expression of these factors was evaluated in the colon of germfree vs. specific pathogen free vs. conventionalized mice and colonic goblet cells were counted. Results: Expression of Hes1 and Hath1, and to a minor degree also of KLF4, was reduced by E. coli K-12 and E. coli Nissle 1917. In contrast, Muc1 and HBD2 expression were significantly enhanced, independent of the Notch signalling pathway. Probiotic E. coli Nissle 1917 regulated Hes1, Hath1, Muc1 and HBD2 through flagellin. In vivo experiments confirmed the observed in vitro effects of bacteria by a diminished colonic expression of Hath1 and KLF4 in specific pathogen free and conventionalized mice as compared to germ free mice whereas the number of goblet cells was unchanged in these mice. Conclusions: Intestinal bacteria influence the intestinal epithelial differentiation factors Hes1, Hath1 and KLF4, as well as Muc1 and HBD2, in vitro and in vivo. The induction of Muc1 and HBD2 seems to be triggered directly by bacteria and not by Notch. © 2013 Becker et al. Source

Ando B.,University of Szeged | Must A.,University of Szeged | Kurgyis E.,University of Szeged | Szkaliczki A.,University of Szeged | And 8 more authors.
Alcohol and Alcoholism

Aims: High relapse rate and extreme difficulty to maintain abstinence are core characteristics of alcohol dependence (AD). Previous studies have demonstrated a persistent decision-making (DM) deficit in AD. We aimed to reveal specific personality features and stress-coping mechanisms presumed to compensate for ineffective DM skills. Methods: Eighty-eight unmedicated patients with AD were enrolled. Intact general cognitive status was assured by IQ above 90. Forty-three patients had an average abstinence period of 12 weeks and were currently in an inpatient treatment program (short-term abstinence group, STA) and 45 patients were abstinent for at least 3 years (long-term abstinence group, LTA). The two groups were assessed using an integrative approach combining domains of DM, temperament and character dimensions and stress-coping measures. Results: Both groups performed at chance level with no linear improvement tendency on the gambling task assessing DM adequacy. The LTA group scored significantly higher on scales of self-directedness and cooperativeness. In contrast, levels of harm avoidance, emotion-oriented coping and perceived stress were significantly higher in the STA group. Conclusion: Our findings provide new evidence for a persistent DM deficit with no learning effect in AD. Despite the deficit, alcohol-dependent patients can achieve LTA. STA patients perceive higher levels of stress and use non-adaptive coping strategies. We propose that the more adaptive personality profile of LTA patients contributes to the compensation of the trait-like DM deficit in alcoholism. These compensatory features represent promising new targets for preventive measures and therapeutic interventions in AD. © The Author 2011. Published by Oxford University Press on behalf of the Medical Council on Alcohol. All rights reserved. Source

Cerase A.,EMBL Mouse Biology Unit | Pintacuda G.,University of Oxford | Tattermusch A.,University of Oxford | Avner P.,EMBL Mouse Biology Unit | Avner P.,Institute Pasteur Paris
Genome Biology

In female m ammals, one of the two X chromosomes in each cell is transcriptionally silenced in order to achieve dosage compensation between the genders in a process called X chromosome inactivation. The master regulator of this process is the long non-coding RNA Xist. During X-inactivation, Xist accumulates in cis on the future inactive X chromosome, triggering a cascade of events that provoke the stable silencing of the entire chromosome, with relatively few genes remaining active. How Xist spreads, what are its binding sites, how it recruits silencing factors and how it induces a specific topological and nuclear organization of the chromatin all remain largely unanswered questions. Recent studies have improved our understanding of Xist localization and the proteins with which it interacts, allowing a reappraisal of ideas about Xist function. We discuss recent advances in our knowledge of Xist-mediated silencing, focusing on Xist spreading, the nuclear organization of the inactive X chromosome, recruitment of the polycomb complex and the role of the nuclear matrix in the process of X chromosome inactivation. © 2015 Cerase et al. Source

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