Global ETD Search

1	Interaction du domaine nucleocapside de la polyprotéine Gag du VIH-1 avec la protéine cellulaire Unr : implication sur la traduction IRES-dépendante du virus / Interaction of the nucleocapsid domain of the Human lmmunodeficiency Virus type-1 with the cellular protein Unr : implication in viral IRES dependent translation Taha, Nedal 03 July 2015 (has links) La protéine de nucléocapside (NC) du virus de l’immunodéficience humaine (VIH-1) joue de nombreux rôles dans les phases précoce et tardive de l’infection. La NC est une protéine à deux doigts de zinc, chaperonne des acides nucléiques. Nous avons cherché de nouveaux partenaires cellulaires de la NCp7 et identifié une protéine de liaison aux ARNs, Upstream of N-ras (Unr), dont l’interaction avec Gag et NCp7 a été confirmée. L’interaction entre Gag et Unr est dépendante de l’ARN et médiée par le domaine NC. Unr est une ITAF (IRES transacting factor) régulant la traduction médiée par plusieurs IRESs cellulaires et viraux. L’ARN génomique du VIH-1 possède deux IRESs dont un localisé dans la région non traduite en 5’ qui permet aux ARNm viraux de conserver un fort niveau de traduction lorsque la traduction coiffe-dépendante de la cellule est affaiblie par l’arrêt du cycle viral induit par l’infection. En utilisant un système de dual luciférase, nous avons montré qu’Unr est une ITAF dont la surexpression stimule l’IRES VIH-1. Des mutations ponctuelles de cet IRES, dans un motif consensus de liaison à Unr, altèrent à la fois l’activité de l’IRES et sa réponse à Unr suggérant que l’activité IRES dépend fortement de Unr. L’effet d’Unr sur l’IRES est inhibé par la surexpression de NCp7 mais pas par celle de Gag dont l’effet stimulateur sur l’IRES est additif de celui d’Unr suggérant un rôle d’Unr différent dans les phases précoce et tardive de l’infection. Pour finir, le knockdown de l’expression d’Unr entraîne une diminution significative de l’infection par un pseudovirus non réplicatif soulignant l’implication fonctionnelle d’Unr dans la phase précoce. / The Human Immunodeficiency Virus-1 (HIV-1) nucleocapsid protein (NC), as a mature protein (NCp7) or as a domain of the polyprotein Gag, plays several important roles in both the early and late phase of the infection. NC is a nucleic acid chaperone protein with two zinc fingers. We searched for new cellular protein partners of NCp7 and identified the RNA binding protein Unr, Upstream of N-ras, whose interaction with both Gag and NCp7 was confirmed. Unr interaction with Gag is RNA dependent and mediated by its NC domain. Unr is an ITAF (IRES trans-acting factor) regulating the translation driven by several IRESs. The HIV-1 genomic mRNA harbors two IRESs elements: one of them found within the HIV-1 5’-Untranslated region drives HIV-1 mRNA translation when the cap-dependent translation is diminished due to the infection-induced cell cycle arrest. Using a dual luciferase assay, Unr was shown to act as an ITAF, increasing the HIV-1 IRES dependent translation. Point mutations of the HIV-1 IRES in a consensus Unr binding motif were found to alter both the IRES activity and its activation by Unr suggesting a strong dependency of the IRES on Unr. Unr stimulation effect is furthermore counteracted by NCp7, but not by Gag overexpression, which increases the IRES activity in an additive manner to Unr suggesting a differential Unr effect on the early and late phases of the infection. Finally, knockdown of Unr in HeLa cells leads to a decline in infection by a non-replicative lentivector proving its functional implication in the early phase. VIH Nucléocapside NCp7 Unr Gag IRES HIV Nucleocapsid NCp7 Unr Gag IRES 579.2 572.6
2	Optimization of row spacing and nitrogen fertilization for cotton Clawson, Ernest Leslie 30 September 2004 (has links) Ultra-narrow row (UNR) cotton (Gossypium hirsutum L.) is a production system using high plant populations in reduced row spacings. The responses of this production system to nitrogen fertilizer have not been fully investigated. Evaluations of yield and earliness of harvest are also important. A three-year study was conducted at the Texas Agricultural Experiment Station farm, Burleson County, TX, on a Ships clay (very-fine, mixed, active, thermic Chromic Hapluderts) and a Weswood silty clay loam (fine-silty, mixed, superactive, thermic Udifluventic Haplustepts). A split plot design was used. Nitrogen fertilizer rates of 0, 50, 101, and 151 kg N ha-1 were applied as the whole plots and row spacings of 19, 38, and 76 cm were established as the split plots. Data included lint yield and yield components, as well as earliness of crop maturity and earliness-related parameters such as boll distribution. Lint yield was increased by higher nitrogen rate. There was no nitrogen rate by row spacing interaction on lint yield, implying fertilizer rates do not need to be changed for UNR systems. Reductions in row spacing did not significantly affect lint yield in any year. Responses such as reduced bolls per plant, increased plant populations, increased ginout, and decreased boll size were often significant and combined to allow the crop to maintain equivalent yields as row spacings were reduced. The slight UNR earliness advantages were probably due to changes in boll distribution. Based on these results, increases in lint yield and earliness may not reliably contribute to the profitability of UNR cotton. ultra-narrow row cotton UNR fertilizer nitrogen earliness
3	Caractérisation du rôle d'Unr, une protéine de liaison à l'ARN, dans les cellules souches embryonnaires murines Elatmani, Habiba 17 December 2009 (has links) Le gène unr (upstream of N-ras) code une protéine de liaison à l’ARN, Unr, qui régule la stabilité et la traduction d’ARN messagers cibles. L’invalidation du gène unr chez la souris conduit à une létalité embryonnaire à mi-gestation (10,5 jours post-coitum, jpc). Unr est donc essentielle pour le développement de la souris. Le phénotype le plus frappant des embryons unr-/- est leur petite taille qui est déjà visible à 8,5jpc. Ce phénotype pourrait refléter un problème précoce de prolifération/différenciation au cours du développement qu’il est possible d’étudier dans les cellules souches embryonnaires (ES). Les cellules ES sont dérivées des cellules pluripotentes des embryons au stade blastocyste (3,5jpc). Les cellules ES peuvent s’auto-renouveler c’est à dire proliférer indéfiniment sous forme non différenciée ce qui correspond à leur état pluripotent ou différencier en tous les types cellulaires (lignages) adultes dérivés des feuillets primordiaux (endoderme définitif, mésoderme et ectoderme) ce que défini la pluripotence. Ces deux propriétés des cellules ES conditionnent leur devenir et définissent leur identité. Nous avons remarqué que les cellules ES unr-/- ont tendance à différencier spontanément alors qu’elles sont cultivées dans des conditions qui les maintiennent dans un état non différencié et prolifératif (état pluripotent). En routine, les cultures de cellules ES unr-/- contiennent environ 25% de cellules morphologiquement différenciées. Nos travaux montrent en effet, qu’elles différencient en endoderme primitif. Nous avons reproduit ce phénotype dans une autre lignée des cellules ES de fond génétique différent par déplétion stable d’Unr. La restauration de l’expression d’Unr dans les cellules ES unr-/- limite fortement leur engagement en différenciation. Unr contribue donc au maintient de l’état pluripotent des cellules ES en prévenant leur différenciation spontanée vers le lignage endodermique primitif (Epr). Ce tissu au cours du développement va former l’épithélium de la poche embryonnaire ou sac vitellin. Nos données préliminaires montrent que les cellules ES en absence d’Unr maintiennent tout de même leur capacité de différenciation multi-lignages (endoderme définitif, mésoderme et ectoderme) quand celle-ci est induite. Ensuite, nous nous sommes intéressés au(x) mécanisme(s) d’action d’Unr. Nous avons fait l’hypothèse qu’Unr pourrait directement agir en régulant positivement des gènes qui inhibent la différenciation des cellules ES en Epr ou en régulant négativement des gènes qui l’induisent. Nous avons identifié le gène gata6 comme cible potentielle d’Unr. Une augmentation modérée de l’expression du facteur de transcription Gata6 dans les cellules ES conduit à une autorégulation positive du gène gata6 et induit la différenciation des cellules ES en Epr. Nos données suggèrent qu’Unr pourrait directement déstabiliser les ARNms Gata6 dans les cellules ES afin de prévenir leur différenciation spontanée en Endoderme primitif. / Unr (upstream of N-ras) is a cytoplasmic RNA-binding protein with cold shock domains, involved in regulation of messenger RNA stability and translation. Unr is essential to mouse development since Embryos deficient for Unr die at mid-gestation. Here we report that unr knockout ES cells maintained under growth conditions that sustain self-renewal spontaneously differentiate toward the primitive endoderm (PrE) lineage. This phenotype was reproduced in another ES line (E14tg2a) after shRNA-induced Unr depletion. Moreover, Unr rescue in Unr-deficient ES cells limits their PrE differentiation engagement. However, Unr is dispensable for multilineage differentiation, as shown by knockout ES cells capacity to produce differentiated teratomas. We further investigated the molecular mechanisms underlying the differentiation of unr-/- ES to primitive endoderm, and found that Unr acts downstream of Nanog. Our data also show Gata6 mRNAs are more stable in Unr-deficient ES cells as compared to wild-type ES cells. We propose that the possible repression by Unr of this key inducer of PrE differentiation at a post-transcriptional level may contributes to the stabilization of ES cells pluripotent state. Unr Etat pluripotent Stabilité Cellules souches embryonnaires (ES) Pluripotence Différenciation spontanée Gata6 Endoderme primitif ARN messagers
4	Drosophila UNR: a factor involved in the translational regulation of dosage compensation Abaza, Irina 03 November 2006 (has links) Dosage compensation is a mechanism that equalizes the expression of X-linked genes in those organisms in which males and females differ in the number of X chromosomes. In Drosophila melanogaster, dosage compensation is achieved by up-regulating the transcription of the single male X chromosome. This effect is mediated by a chromatin remodeling complex known as the Male Specific Lethal (MSL) complex or Dosage Compensation Complex (DCC). In female flies, dosage compensation is inhibited primarily because of the translational repression of the mRNA encoding one of the DCC subunits, MSL-2, by the female-specific RNA binding protein Sex-lethal (SXL). To inhibit translation, SXL binds to poly(U) stretches present in both the 5’ and 3’ UTRs of msl-2 mRNA. Sequences adjacent to those SXL-binding sites in the 3´UTR are also required for translation inhibition and are bound by co-repression. In this thesis work, we have designed an affinity chromatography assay to isolate the putative co-repressor(s), and have identified the protein Upstream of N-ras (UNR). Drosophila UNR (dUNR) is an ubiquitous, conserved protein that contains 5 cold shock domains (CSD) and a glutamine- (Q) rich amino- terminal extension. We show that dUNR is a necessary co-factor for SXL-mediated msl-2 repression. SXL recruits dUNR to the 3’ UTR of msl-2 mRNA, imparting a sex-specific function to this ubiquitous protein. Domain mapping experiments indicate that dUNR interacts with SXL and msl-2 mRNA through CSD1, and that the domains for translation inhibition and SXL interaction can be distinguished. Our data indicate that the Q-rich domain, together with CSDs 1 and 2, plays an important role in translational repression, and suggest that factors in addition to dUNR and SXL are required for repression of msl-2 mRNA. Using a combination of UNR immunoprecipitation and microarray analysis, we have identified the mRNAs that are bound to dUNR in male and female flies. Our results suggest that dUNR is not only a novel regulator of dosage compensation, but also a general post-transcriptional regulator of gene expression. translation initiation translational control 5’UTR binding proteins 3’ UTR binding proteins SXL dosage compensation msl-2 UNR poly(A) tail and PABP microarrays co-repressors 575
5	Ukraїnas självständighet 1917 i svensk press 1917–1918 / Ukraine’s independence 1917 in swedish press 1917–1918 Bergman, Leo January 2017 (has links) This dissertation is a quantitative study with elements of qualitative analysis. The purpose of this quantitative study was to investigate WHAT was written about Ukraine's independence 1917 in Swedish press 1917–1918. The qualitative part of the survey was intended to answer the question if the newspaper's political attitude influenced the news reports during the chosen period. The exact periodization was determined to be between March 1, 1917 and June 30, 1918. This periodization was chosen because of the March Revolution in 1917, which triggered independence declarations in a number of countries oppressed by Moscow, who now saw their chance of freedom. June 1918 became the end of the investigation because it was just when the peace agreement between Ukraine and the Soviet Union was signed. The source material has been chosen to represent a multitude of ideological orientations. It was liberal, moderate, conservative, liberal and left-wing orientations. The source material consisted of newspaper articles from the following newspapers: Dagens Nyheter, Aftonbladet, Göteborgs Aftonblad, Svenska Dagbladet, Dalpilen, Kalmar Tidning and Norrskensflamman. Quantitative methodology was used on the source material. This method consisted of a reviewing of newspaper articles in searching of news reports from Ukraine or articles which had something to do with the events in Ukraine. Every newspaper was searched day after day. The crawled material was presented in two chapters representing different periods. The first chapter of the results presented the results from 1917, and more precisely from March to December 1917. The second chapter presented the results from 1918, but also from December 1917, that is, the result from December 1917 through June 1918. The whole result was then discussed in a separate chapter where the qualitative analysis was also discussed. The result of the quantitative analysis showed that it has been written relatively sparcely about Ukraine's independence although the volume of articles increased from December 1917 and even more in 1918. Sometimes there were articles on the first page. But for the most part, the articles with Ukraine issues were placed among other foreign articles. It was also found in the survey that it was the first World War that drew attention to the newspapers, even though the events in Petrograd and then in Ukraine took more space. This survey also showed that what was written about Ukraine's independence was also what appears in the reference literature. The news reports reported how Ukraine proclaimed independence in March 1917 and later on proclaimed an independent republic in November 1917 when the Bolsheviks conducted their coup d'état in Petrograd. The newspapers also wrote how the Russian Communists sent a declaration of war to Ukraine in December 1917 and about the war that followed. The articles also tell us how negotiations on Ukraine Peace went on in Brest-Litovsk, and how they ended up with alliance between Germany and Ukraine with the campaign against the communists. It was told how the German army marched into Ukraine to free it from the bolsheviks. Until May 1918 there were battles between the German-Ukrainian Army and the Communists. In June 1918 the peace agreement was signed and this survey’s investigation ended. The survey showed that it was written about Ukraine's independence in all newspapers. Dagens Nyheter had the most news articles linked to the survey. Although the number of articles was not subject for analysis in this survey. The qualitative analysis was based on using Höjelid's theoretical concepts "positive sound" and "negative sound" on the quantitative analysis material. The qualitative analysis’ result showed that it was almost impossible to see the differences between the newspapers because the articles were traded between the newspapers, i.e. the content was copied straight away. It should be noted that not all content was the subject of copying between the newspapers. Copying occurred to a greater extent, but there were still original articles derived from the respective newspaper. Most of the articles were also direct telegrams that were communicated abroad to the newspaper's editors. A lot of these telegrammic articles were sent with a purpose to mislead society. These angled articles were published without further examination in Swedish press. There were articles from, for example, Dagens Nyheter whose editors noted the "strange Petrograd reports" and informed about it for the purpose of enlightening the public. However, as most newspapers were occupied with World War I, as was shown in the source material, the newspaper editorial office was less interested in other foreign events. Therefore, such angled articles could be found in Swedish press on a larger scale. / Denna avhandling är en kvantitativ studie med inslag av kvalitativ analys. Syftet med denna kvantitativa studien var att undersöka VAD som skrevs om Ukrajinas självständighet 1917 i svensk press 1917–1918. Den kvalitativa delen av undersökningen ämnade att besvara frågan om tidningens politiska hållningen påverkade nyhetsrapporteringen under den valda perioden. Den exakta periodiseringen fastställdes att vara mellan den 1 mars 1917 och den 30 juni 1918. Denna periodisering valdes på grund av marsrevolutionen 1917 som utlöste självständighets-förklaringar i en rad länder som var förtryckta av Moskovitien och som nu såg sin chans till frihet. Juni 1918 blev slutpunkten i undersökningen därför att det var just då som fredsavtalet mellan Ukrajina och Sovjet undertecknades. Källmaterialet har valts att representera en mångfald ideologiska inriktningar. Det var liberal, moderat, konservativ, frisinnad samt vänstersocial inriktningar. Källmaterialet bestod av tidningsartiklar från följande tidningar: Dagens Nyheter, Aftonbladet, Göteborgs Aftonblad, Svenska Dagbladet, Dalpilen, Kalmar tidning och Norrskensflamman. Det användes kvantitativ metod på källmaterialet som bestod i en genomsökning av tidningsartiklarna efter nyhetsrapporter från Ukrajina eller som hade något med händelserna i Ukrajina att göra. Varje tidning genomsöktes dag för dag. Det genomsökta materialet presenterades i två kapitel som representerade olika perioder. Det första resultatkapitlet presenterade resultatet från år 1917, och mer exakt från mars till december 1917. Det andra kapitlet presenterade resultatet från år 1918, men även från december 1917, det vill säga resultatet från och med december 1917 till och med juni 1918. Det hela resultatet diskuterades sedan i ett eget kapitel där även den kvalitativa analysen diskuterades. Resultatet från den kvantitativa analysen visade att det har skrivits relativt sparsmakat om Ukrajinas självständighet även om artikelmängden ökade från december 1917 och ännu mer under 1918. Ibland förekom det artiklar på första sidan. Men för det mesta placerades artiklarna med Ukrajina-frågor bland andra utlandsartiklar. Det framgick också i undersökningen att det var mest första världskriget som upptog tidningarnas uppmärksamhet, även om händelserna i Petrograd och sedan i Ukrajina tog allt mer plats allt eftersom. Denna undersökning visade också att det som skrevs om Ukrajinas självständighet var också det som förekommer i referenslitteraturen. Nyhetsrapporterna berättade hur Ukrajina utropat sin självständighet i mars 1917 tills landet proklamerat en oberoende republik i november 1917 när bolsjevikerna genomförde sin statskupp i Petrograd. Tidningarna skrev också hur de ryska kommunisterna skickade krigsförklaring till Ukrajina i december 1917 och om det kriget som följde efter det. Artiklarna berättar även om hur förhandlingarna för Ukrajinafreden gick till i Brest-Litovsk samt hur dessa avslutades med att Tyskland allierade sig med Ukrajina i kampen mot kommunisterna. Det berättades hur den tyska armén marscherade in i Ukrajina för att befria det från bolsjevikerna. Fram till maj 1918 pågick det strider mellan tysk-ukrajinska armén och kommunisterna. I juni 1918 undertecknades fredsavtalet och där slutade undersökningen. Undersökningen visade att det skrevs om Ukrajinas självständighet i samtliga tidningar. Dagens Nyheter hade flest nyhetsartiklar kopplade till undersökningen. Även om antalet artiklar ej var i syfte att analysera i denna undersökning. Den kvalitativa analysen gick ut på att använda Höjelids teoretiska begrepp ”positiv klang” och ”negativ klang” på den kvantitativa analysens resultatmaterial. Det kvalitativa resultatet visade att det var nästintill omöjligt att se skillnad mellan de olika tidningarna eftersom artiklarna traderades mellan tidningarna, det vill säga innehållet kopierades rakt av. Det bör påpekas att inte allt innehåll var ämne för kopiering mellan tidningarna. Kopieringen förekom i större utsträckning men det fanns ändå originella artiklar som härstammade från respektive tidning. De flesta av artiklarna var dessutom direkta telegram som kommunicerades i utlandet till tidningens redaktioner. En hel del av dessa telegraferade artiklar skickades med ett givet syfte att vilseleda samhällsopinionen. Dessa vinklade artiklar publicerades utan vidare granskning i svensk press. Det förekom artiklar från exempelvis Dagens Nyheter vars redaktion uppmärksammat de ”märkliga Petrogradrapporter” och informerat om det i möjligt syfte att upplysa allmänheten. Men eftersom de flesta tidningarna var upptagna med första världskriget, som det visades i källmaterialet, var tidningsredaktionerna mindre intresserade av andra utländska händelser. Därför kunde sådana vinklade artiklar förekomma i svensk press i en större omfattning. Ukraine Peace Ukraїna Ukraine independence 1917 1918 independence movement peace treaty invasion invasion war independence war freedom war freedom struggle Dagens Nyheter Svenska Dagbladet holodomor 1921 1923 Norrskensflamman Moskali Dalpilen Kalmar tidning Göteborgs Aftonblad Aftonbladet Kyiv Odesa Charkiv Dnipro Crimea revolution UNR Ukraine’s National Republic press swedish press press survey press study communism leninism Moksel genocide Petrograd coup d'état CHEKA nkvd Moskau GPU KGB lenin Red Army Soviet Soviet Union bolsheviks socialists Moscovia red terror communist terror SSU socialdemocrats red guardian red guard white guardian black guard Finland Sweden Finnish independence movement terrorist organization commission civil war invasion genocide proletarian bolshevik terror cadets moscovian threat russian threat muscovites Pultava Poltava Tauria Katerynoslaw Chernihiv Ottokar Czernin Weimar republic Deutsches Reich interim government national hero mensheviks maximalists minimalists provisional government Rada supremacy central powers Germany Deutschland German Empire Kaiser Wilhelm Treaty of Brest-Litovsk Belarus communist propaganda Mohilev peace negotiation Caucasus Cuban Don Ukrajina UkrajinaFreden Ukraїna Ukraina självständighet 1917 1918 självständighetsrörelse Tidningsuppsats presstudie pressundersökning tidningsstudie dagspress rikspress Dagens Nyheter Svenska Dagbladet Norrskensflamman Moskali Dalpilen Holodomor 1921 1923 Kalmar tidning Göteborgs Aftonblad Aftonbladet Kommunism Sovjet bolsjeviker Petrograd Krim Charkiv Odesa Dnipro Kyjiv Revolution Leninism statskupp TJEKA nkvd GPU KGB lenin invasionskrig invasion fredsavtal socialister kommunister röda armén röd terror kommunistisk terror SSU socialdemokrater rödgardister vitgardister svarta gardet Finland Sverige finska självständighetsrörelsen terrororganisation kommission inbördeskrig folkmord självständighetskrig proletär bolsjevikiska terrorismen kadetterna ryssar rysshotet Moskovitien Poltava Pultava Taurien Katerynoslaw Tjernihiv Czernin nationalhjälte mensjeviker maximalisterna minimalisterna interimregering provisorisk regering rada suprematien centralmakterna Tyskland Weimar republic Deutsches Reich Tyska riket Kaiser Wilhelm Treaty of Brest-Litovsk Belarus kommunistpropaganda Mohilev fredsförhandling Kaukasus Kuban Don History Historia

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