oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 2 )

2019 ( 14 )

2018 ( 16 )

2017 ( 20 )

Custom range...

Search Results: 1 - 10 of 2076 matches for " Didier Devys "
All listed articles are free for downloading (OA Articles)
Page 1 /2076
Display every page Item
In Vivo Chromatin Organization of Mouse Rod Photoreceptors Correlates with Histone Modifications
Caroline Kizilyaprak,Danièle Spehner,Didier Devys,Patrick Schultz
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0011039
Abstract: The folding of genetic information into chromatin plays important regulatory roles in many nuclear processes and particularly in gene transcription. Post translational histone modifications are associated with specific chromatin condensation states and with distinct transcriptional activities. The peculiar chromatin organization of rod photoreceptor nuclei, with a large central domain of condensed chromatin surrounded by a thin border of extended chromatin was used as a model to correlate in vivo chromatin structure, histone modifications and transcriptional activity.
Lessons from genome-wide studies: an integrated definition of the coactivator function of histone acetyl transferases
Krishanpal Anamika, Arnaud R Krebs, Julie Thompson, Olivier Poch, Didier Devys, Làszlò Tora
Epigenetics & Chromatin , 2010, DOI: 10.1186/1756-8935-3-18
Abstract: Histone post-translational modifications have shown to be key regulators among transcription regulation mechanisms [1,2]. Histone acetylation is known to play an important role in the regulation of transcriptional activity in eukaryotic cells [3] by affecting higher-order folding of chromatin fibres, loosening of the contacts between the DNA and the nucleosomes and/or histone-nonhistone protein interactions [4-8]. Histone acetylation on various target lysines is in general positively associated with gene expression. Thus, HATs (also called lysine acetyl transferases or KATs) are thought to increase the decompaction of chromatin, which in turn may increase the accessibility of factors that promote transcription [8-11]. In higher eukaryotes, two enzymatic families (GNAT and MYST), each containing a dozen histone acetyltransferase (HAT) enzymes, have been identified and have often been shown to be subunits of larger transcriptional coactivator complexes.Over the past decade, two approaches were mainly used to better understand the functional specificity of HATs. First, in vitro acetylation assays were carried out to investigate the substrate specificity of distinct HATs. These analyses showed that HATs exert a certain degree of specificity for particular lysine residues on different histone tails. Second, in vivo gene inactivation studies allowed testing the HAT specificity by observing phenotypical effects caused by ablation of a particular HAT. Interestingly, most of these studies argued for a high degree of specificity in the developmental or gene expression phenotypes. More recently, availability of new high-throughput technologies such as chromatin immunoprecipitation sequencing (ChIP-seq) allowed the investigation of the recruitment of HATs and the deposition of acetylation marks at a genome-wide scale [12,13]. Contrary to the biochemical and genetic evidence, when carefully analysed, the genome-wide data suggest a low specificity in the recruitment and activity
Glutamine-Expanded Ataxin-7 Alters TFTC/STAGA Recruitment and Chromatin Structure Leading to Photoreceptor Dysfunction
Dominique Helmlinger,Sara Hardy,Gretta Abou-Sleymane,Adrien Eberlin,Aaron B. Bowman,Anne Gansmüller,Serge Picaud,Huda Y. Zoghbi,Yvon Trottier,Làszlò Tora,Didier Devys
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0040067
Abstract: Spinocerebellar ataxia type 7 (SCA7) is one of several inherited neurodegenerative disorders caused by a polyglutamine (polyQ) expansion, but it is the only one in which the retina is affected. Increasing evidence suggests that transcriptional alterations contribute to polyQ pathogenesis, although the mechanism is unclear. We previously demonstrated that theSCA7 gene product, ataxin-7 (ATXN7), is a subunit of the GCN5 histone acetyltransferase–containing coactivator complexes TFTC/STAGA. We show here that TFTC/STAGA complexes purified from SCA7 mice have normal TRRAP, GCN5, TAF12, and SPT3 levels and that their histone or nucleosomal acetylation activities are unaffected. However, rod photoreceptors from SCA7 mouse models showed severe chromatin decondensation. In agreement, polyQ-expanded ataxin-7 induced histone H3 hyperacetylation, resulting from an increased recruitment of TFTC/STAGA to specific promoters. Surprisingly, hyperacetylated genes were transcriptionally down-regulated, and expression analysis revealed that nearly all rod-specific genes were affected, leading to visual impairment in SCA7 mice. In conclusion, we describe here a set of events accounting for SCA7 pathogenesis in the retina, in which polyQ-expanded ATXN7 deregulated TFTC/STAGA recruitment to a subset of genes specifically expressed in rod photoreceptors, leading to chromatin alterations and consequent progressive loss of rod photoreceptor function.
Glutamine-Expanded Ataxin-7 Alters TFTC/STAGA Recruitment and Chromatin Structure Leading to Photoreceptor Dysfunction
Dominique Helmlinger,Sara Hardy equal contributor,Gretta Abou-Sleymane equal contributor,Adrien Eberlin,Aaron B Bowman,Anne Gansmüller,Serge Picaud,Huda Y Zoghbi,Yvon Trottier,Làszlò Tora ,Didier Devys
PLOS Biology , 2006, DOI: 10.1371/journal.pbio.0040067
Abstract: Spinocerebellar ataxia type 7 (SCA7) is one of several inherited neurodegenerative disorders caused by a polyglutamine (polyQ) expansion, but it is the only one in which the retina is affected. Increasing evidence suggests that transcriptional alterations contribute to polyQ pathogenesis, although the mechanism is unclear. We previously demonstrated that theSCA7 gene product, ataxin-7 (ATXN7), is a subunit of the GCN5 histone acetyltransferase–containing coactivator complexes TFTC/STAGA. We show here that TFTC/STAGA complexes purified from SCA7 mice have normal TRRAP, GCN5, TAF12, and SPT3 levels and that their histone or nucleosomal acetylation activities are unaffected. However, rod photoreceptors from SCA7 mouse models showed severe chromatin decondensation. In agreement, polyQ-expanded ataxin-7 induced histone H3 hyperacetylation, resulting from an increased recruitment of TFTC/STAGA to specific promoters. Surprisingly, hyperacetylated genes were transcriptionally down-regulated, and expression analysis revealed that nearly all rod-specific genes were affected, leading to visual impairment in SCA7 mice. In conclusion, we describe here a set of events accounting for SCA7 pathogenesis in the retina, in which polyQ-expanded ATXN7 deregulated TFTC/STAGA recruitment to a subset of genes specifically expressed in rod photoreceptors, leading to chromatin alterations and consequent progressive loss of rod photoreceptor function.
From America to Africa: A Parallel in the Colonial and Federal Experiences  [PDF]
Didier Kombieni
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.310003
Abstract: The present article aims at exhibiting similarities within the colonial experiences and the federal experiences of America and Africa, despite the disparities with the two processes, then pointing out the stepping of the African countries despite their moving from the Organization of the African Unity (OAU) to the African Union (AU). In effect, this change could just be seen as an awkward imitation of the American successful federal process, from the Articles of Confederation to the United States of America, since America had been senior in that process. From then, further research might decide to project what Africans could use as a frame of reference in their American equivalent concerning the search for an integrated society, and an accepted democracy among the separate and equal nations.
H2B Mono-ubiquitylation Facilitates Fork Stalling and Recovery during Replication Stress by Coordinating Rad53 Activation and Chromatin Assembly
Chia-Yeh Lin equal contributor,Meng-Ying Wu equal contributor,Sophie Gay,Lisette Marjavaara,Mong Sing Lai,Wei-Chun Hsiao,Shih-Hsun Hung,Hsin-Yi Tseng,Duncan Edward Wright,Chen-Yi Wang,Guoo-Shyng W. Hsu,Didier Devys,Andrei Chabes,Cheng-Fu Kao
PLOS Genetics , 2014, DOI: doi/10.1371/journal.pgen.1004667
Abstract: The influence of mono-ubiquitylation of histone H2B (H2Bub) on transcription via nucleosome reassembly has been widely documented. Recently, it has also been shown that H2Bub promotes recovery from replication stress; however, the underling molecular mechanism remains unclear. Here, we show that H2B ubiquitylation coordinates activation of the intra-S replication checkpoint and chromatin re-assembly, in order to limit fork progression and DNA damage in the presence of replication stress. In particular, we show that the absence of H2Bub affects replication dynamics (enhanced fork progression and reduced origin firing), leading to γH2A accumulation and increased hydroxyurea sensitivity. Further genetic analysis indicates a role for H2Bub in transducing Rad53 phosphorylation. Concomitantly, we found that a change in replication dynamics is not due to a change in dNTP level, but is mediated by reduced Rad53 activation and destabilization of the RecQ helicase Sgs1 at the fork. Furthermore, we demonstrate that H2Bub facilitates the dissociation of the histone chaperone Asf1 from Rad53, and nucleosome reassembly behind the fork is compromised in cells lacking H2Bub. Taken together, these results indicate that the regulation of H2B ubiquitylation is a key event in the maintenance of genome stability, through coordination of intra-S checkpoint activation, chromatin assembly and replication fork progression.
Characteristics of Patients with Upstaging by Sentinel Lymph Node Biopsy of the N0 Neck in Head and Neck Cancer  [PDF]
Didier Dequanter, Philippe Lothaire
Journal of Cancer Therapy (JCT) , 2011, DOI: 10.4236/jct.2011.22037
Abstract: Introduction: To investigate the possible role of sentinel lymph node biopsy (SLNB) to upstage the N0 neck in patients with oral and oropharyngeal squamous cell carcinoma. Methods: Patients with T1-T2 oral and oropharyngeal squamous cell carcinoma accessible to injection and staged N0 into the neck by palaption and CTscan were enrolled in the study. All patients underwent regular follow-up to identify possible recurrence. Results: A sentine lymph node biopsy was performed by 21 consecutive patients. 4 of the 21 patients were upstaged by SNLB. There was a mean follow-up of 31 months. Two patients developed subsequent disease after having been staging by SLNB, respectively negative in one case and positive in the other case. Tumor site, the staging of the primary tumor, presence of ulceration, tumor thickness were the same in the upstaged initially N0 patients. Conclusions: Sentinel lymph node biopsy can be used to upstage the N0 neck patients in perhaps well defined patients.
Theoretical Reserve Price in Forestry  [PDF]
Francis Didier Tatoutchoup
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.64080
Abstract: This article uses the forest management problem under uncertainty to derive the optimal reservation price when a standing timber is to be auctioned. Theoretically, the resulting optimal reservation price that considers the harvesting decision is an extended version of Laffont and Maskin’s and Riley and Samuelson’s reservation price, which is suboptimal in the forestry context.
Empirical Reserve Price in Forestry: Application to US Forest Service  [PDF]
Francis Didier Tatoutchoup
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.65093
Abstract: This article exploits data from ascending auctions from the US Forest Service to estimate an optimal reservation price in forestry when prices are uncertain and when the forest owner endogenizes the cutting age of trees. The results suggest that there is a huge gain in terms of the forest owner profit to use the estimated optimal reservation price rather the well-known reservation price proposed by Laffont and Maskins and Riley and Samuelson’s which is suboptimal in the forestry context. Finally, the results also confirm that the reservation price set by the US government agency is too low.
Prediction of fluid challenge effect: filling pressure when left ventricular function is abnormal, diastolic volume when left ventricular function is normal
Didier Payen
Critical Care , 2011, DOI: 10.1186/cc10067
Abstract: When hypovolemia is strongly suspected, prediction of the fluid challenge response remains difficult for the intensivist or the anesthesiologist, because of complex interactions. In addition to the clinical art, each physician wants to use numerical parameters to make the decision to give fluid and to ensure an adequate response to the fluid given. Apart from the debate on the type of fluid, the best way to evaluate the fluid challenge response has motivated a lot of clinical research aiming to demonstrate the specificity and sensitivity of several parameters, considering the invasiveness, the accuracy, and the cost of the methods.In the past decade, many devices and parameters have been proposed to dynamically evaluate the response to fluid challenge. If fluid has to be given, the goal remains multifactorial, oscillating between hypotension correction, improvement in cardiac function, increase in cardiac output and oxygen delivery, or vascular recruitment. The effectiveness of this fluid challenge has been assessed by different methods: (1) echocardiography showing a better function of the right and left ventricles or better filled inferior or superior vena cava; (2) changes in oxygen delivery, which is simplified when arterial oxygen saturation is normal in changes in cardiac output, whatever the techniques for cardiac output measurements used; (3) changes in pulse pressure amplitude based on determinants of systolic and diastolic arterial blood pressure; or (4) cardiac filling pressure variations in association with cardiac output, according to the Frank-Starling law, but with invasive methods.The study from Trof and colleagues examines the interest in measuring cardiac filling pressures or the diastolic cardiac volume index (global end-diastolic volume index) in cardiac or vascular surgery in the post-operative period, in the presence or absence of systolic left ventricular dysfunction [1]. The later parameter the global ejection fraction (GEF) was obtained from
Page 1 /2076
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.