• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 137
  • 133
  • 36
  • 33
  • 13
  • 11
  • 11
  • 6
  • 5
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 449
  • 89
  • 78
  • 71
  • 60
  • 51
  • 49
  • 38
  • 36
  • 36
  • 33
  • 29
  • 25
  • 24
  • 24
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

První anglická "kolonie"? Příspěvek ke studiu anglo-waleských vztahů ve 13. století. / The First English "Colony"? A contribution to the study of the anglo-welsh relationships in 13th century.

Bartošík, Jan January 2021 (has links)
The thesis studies political, legal and cultural historical events on the land of present Wales in the high medieval period. The emphasis is put on the rule of Llywelyn ap Gruffudd (1246-1282) associated with the english invasion into Wales by Edward I. The study concentrates on understanding of the conflict in a historical context and on an analysis of legal sources. The work is divided into three main parts. First part focus on the cultural-legal essence of medieval Wales and with it bounded political cohabitation of an individual welsh leaders. Second part of this work analyzes situation in the high medieval England, characterizes so-called Welsh March and a mutual anglo-welsh cohabitation. The last part analyzes the culmination of the conflict as a consequence of the aspects described in previous parts of this work, the conflict between Llywelyn and Edward I. and the subsequent arrengment of Wales.
92

Vejo um museu de grandes novidades, o tempo não para ... sociopoetizando o museu e musealizando a vida. / see a museum of great news, not the time to ... sociopoetizando the museum and musealizando life

Albuquerque, Elane Carneiro January 2008 (has links)
ALBUQUERQUE, Elane Carneiro. Vejo um museu de grandes novidades, o tempo não para... sociopoetizando o museu e musealizando a vida. 2008. 159f. Dissertação (Mestrado em Educação) – Universidade Federal do Ceará, Faculdade de Educação, Programa de Pós-Graduação em Educação Brasileira, Fortaleza-CE, 2008. / Submitted by Maria Josineide Góis (josineide@ufc.br) on 2012-07-06T12:39:44Z No. of bitstreams: 1 2008_Dis_ECAlbuquerque.pdf: 10880080 bytes, checksum: 2f35dd9bc1b10c057c45b8638404469d (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2012-07-09T11:43:19Z (GMT) No. of bitstreams: 1 2008_Dis_ECAlbuquerque.pdf: 10880080 bytes, checksum: 2f35dd9bc1b10c057c45b8638404469d (MD5) / Made available in DSpace on 2012-07-09T11:43:19Z (GMT). No. of bitstreams: 1 2008_Dis_ECAlbuquerque.pdf: 10880080 bytes, checksum: 2f35dd9bc1b10c057c45b8638404469d (MD5) Previous issue date: 2008 / This label has an analysis of an investigative process that has the purpose to study the relation between the museum and the population in an Popular Education perspective and the new museum, through a discover of some conceptions that the community do about the word museum. For this, it was optioned to an optional collective ‘Sociopoetico’ research, that gives the possibility the production about a generation theme, in concerning with body and symbol languages developed by workshops, with a research group participation formed by facilitators, in other words, official researchers of the community. The research was made by Comunidade Remanescente de Quilombo da Área de Proteção Ambiental – APA from Curiaú, a city situated in Macapá in Amapá State from 2005 to 2008. It comes from the study around the invisibility and situations about the heritage African cultures denies that the black population, in specify, quilombola communities live by the Brazilian cultural institutions society. The research gave the possibility to analyze the museum institutions work in the recognizing and preservation of the Brazilian cultural patrimony beyond a dialog between institute conceptions made by the quilombola community about museum, coming true the quilombo’s potency as a museum space to be considered by the Education an Museum. The study points the viewless of a museum and pedagogy action full of ideal and ethnocentric constructions without considering the participation and the history of popular groups, as well as African references in social and cultural production and Brazilian economy. In the other hand, the concepts produced by the research group show the perception of the museum in order to quilombola and the community daily. It also has some contrapositions possibilities, considering the necessity of a review in the educative action intending to combat social and racial inequality / Esse trabalho consta da análise do processo investigativo que teve como proposta estudar a relação entre museu e população na perspectiva da Educação Popular e da Nova Museologia, através da descoberta de conceitos que a comunidade produz sobre o que seja museu. Para tanto, optou-se pelo método de pesquisa coletiva Sociopoético, que possibilita a produção de conceitos acerca de um tema gerador, mediante linguagens corporais e simbólicas desenvolvidas por meio de oficinas, com a participação do grupo pesquisador formado de facilitadores/as, ou seja, de pesquisadores/as oficiais e de pessoas da comunidade. O estudo foi realizado na Comunidade Remanescente de Quilombo da Área de Proteção Ambiental – APA do Curiaú, município de Macapá no Estado do Amapá, durante o período de 2005 a 2008. Parte-se da problemática em torno da invisibilidade e situação de negação das heranças culturais africanas que a população negra e, mais especificamente, as comunidades quilombolas vivenciam por parte da sociedade e das instituições culturais no Brasil. A pesquisa possibilitou analisar o papel das instituições museológicas no reconhecimento e na preservação do patrimônio cultural brasileiro por meio do diálogo entre os conceitos instituídos e os conceitos produzidos pela comunidade quilombola sobre museu, revelando a potencialidade do quilombo como espaço museológico a ser considerado pela Educação e pela Museologia. O estudo aponta a vigência de uma ação museológica e pedagógica eivada de construções ideológicas etnocêntricas e elitistas, sem considerar a participação e a história dos grupos populares, assim como as referências africanas existentes na produção sócio-cultural e econômica brasileira. Por outro lado, os conceitos produzidos pelo grupo-pesquisador revelam a percepção de museu a partir do ser quilombola e do cotidiano na comunidade. Infere algumas possibilidades de contraposições, levando em conta a necessidade de uma revisão na ação educativa dos museus tendo em vista combater as desigualdades sociais e raciais
93

Reload Disobedience

Züger, Theresa 19 December 2017 (has links)
Diese Arbeit verbindet zwei Perspektiven, nämlich den Blick auf die soziale Praxis des digitalen Ungehorsams mit dem anhaltenden Diskurs über zivilen Ungehorsam in der politischen Theorie. Digitaler Ungehorsam entwickelte sich im Verlauf der Evolution digitaler Informations- und Kommunikationstechnologien in überraschendem Facettenreichtum: vom BTX Hack des Chaos Computer Clubs über den Widerstand der Cypherpunks für die weltweite Verbreitung von Verschlüsselung hin zu Anonymous, Aaron Swartz und Edward Snowden. Reload Disobedience plädiert für eine Revision des dominierenden Verständnisses von zivilem Ungehorsam und stützt sich dabei auf Theorien von Hannah Arendt, Michael Walzer und Etienne Balibar. Viele Beispiele in der Geschichte des digitalen Ungehorsams werden diesem neuen Verständnis durchaus gerecht, doch gibt es gleichzeitig Faktoren, die weitere Fragen aufwerfen: Kann ziviler Ungehorsam anonym sein oder automatisiert durchgeführt werden? Wie verändert sich das kollektive Handeln, das maßgeblicher Teil der Tradition zivilen Ungehorsames ist, durch die globale Vernetzung? Um diese und andere Effekte digitalen Handelns zu verstehen, diskutiert die Autorin die Entscheidungen der digital Ungehorsamen sowie Möglichkeiten und Grenzen digitalen Handelns im Kontext demokratie-theoretischer Überlegungen. Eine Kernthese der Arbeit ist, dass ziviler Ungehorsam in digitalen Formen potentiell eine neue Direktheit des Politischen erzeugen kann. Gleichzeitig muss sich diese Praxis einer besonderen Unsicherheit sowie neuen Risiken und Herausforderungen stellen, um dem demokratischen Geist des zivilen Ungehorsams unter neuen Bedingungen gerecht zu werden. / This work combines two perspectives, namely the social and activist history of digital forms of disobedience with the ongoing discourse around civil disobedience in political theory. In the course of the internet’s evolution, digital disobedience developed in a surprisingly multifaceted nature: From cases like the BTX Hack of the Chaos Computer Club, to the Cypherpunks and their effort to spread encryption, from Anonymous to Aaron Swartz or Edward Snowden. This work argues for a broader understanding of civil disobedience than the mainstream in political thinking suggests based on arguments from a radical democratic line of thinking, inspired by Hannah Arendt, Michael Walzer and Etienne Balibar. Many cases of digital disobedience meet the spirit of this new understanding, while at the same time their digital nature provokes a new set of questions as well. For instance the question, if civil disobedience may be anonymous or even automated. How does the internet change collective action which is often seen as a core element of the tradition of civil disobedience? The author discusses the choices and principles behind digitally disobedient action as well as the possibilities and limits of digital action in the context of democratic theory. She shows that civil disobedience in digital action even develops a new directness of encounter that adds a new potential to this delicate form of political action. Nevertheless, digital practices of civil disobedience are at the same time precarious and faced with new risks and challenges, like automation of and the risk of elitist tech-avant-gardes overriding the democratic spirit that civil disobedience is rooted in.
94

Das Kino der VRP im DDR-Alltag

Piatkowska, Kinga 19 December 2011 (has links)
Mit dem Ende des Zweiten Weltkrieges und mit der Proklamierung der DDR im Jahre 1949 wurde ein neues Kapitel in der Geschichte der deutsch-polnischen Beziehungen eröffnet. Die DDR und die Volksrepublik Polen wurden der Regierung der Sowjetunion unterstellt und als „Brüderländer“ aufgefordert, gegenseitige Kontakte in verschiedenen Bereichen zu pflegen. Eines von diesen Gebieten war auch das kulturelle Leben, von dem ein bedeutender Teil der Filmaustausch war. In den Jahren 1949-1990 wurden im Lichtspielwesen der DDR über 300 Spielfilme aus der Volksrepublik Polen verliehen, was zweifelsohne eine imposante Anzahl war. Die große Mehrheit dieser Filme wurde in der DDR-Presse rezensiert. 40 Jahre lang waren die Kritiken in Bezug auf das Filmangebot aus der Volksrepublik Polen im Lichtspielwesen der DDR ein fester Bestandteil der DDR-Alltags- und Kinopresse. Es sind innerhalb von dieser Zeit tausende von Rezensionen zu polnischen Filmen geschrieben worden, von deren ein großer Teil in dieser Arbeit analysiert wurde. Die Analyse der Pressebeiträge stellt ein Bild der Beurteilungen der polnischen Produktionen durch die DDR-Journalisten dar, lässt aber auch ganz genau Änderungen in den Beziehungen zwischen der Volksrepublik Polen und der DDR in den Jahren 1949-1989 erkennen. Dadurch bildet die politische Situation in den beiden Nachbarländern den Hintergrund dieser Arbeit, wobei fünf wichtige geschichtliche Phasen ausgewählt werden, die die Kapitel der Arbeit bilden. Zwei Unterkapitel dieser Arbeit werden der Rezeption der Filme von zwei bedeutendsten polnischen Regisseuren der Nachkriegszeit gewidmet: Andrzej Wajda und Krzysztof Zanussi. / With the end of the Second World War, and the formation of the DDR in 1949, a new chapter in the history of German-Polish relations began. The DDR and the People''s Republic of Poland were placed under the control of the Soviet Union, and as “brother lands” were encouraged to foster a mutual contact and exchange in various areas. One such area of exchange was in cultural life, of which a significant part was the sharing of films from both countries. In the years 1949-1990 over 300 Polish films were distributed in East German cinemas, an indisputably significant figure. The great majority of these films were reviewed in the DDR press, and in fact reviews of the cinematic offerings from the People''s Republic of Poland formed a regular component of East German newspapers during this period of 40 years. Over this time, thousands of reviews of Polish films were written, a large number of which are analysed in this dissertation. The analysis of press articles forms a picture of how Polish film productions were regarded by DDR journalists, but also reveals the changing relationship between the two countries in the period from 1949 to 1989. Thus the political situation in these neighbouring countries forms the background of this dissertation, with each chapter discussing one of five important historical phases. Two sub-chapters of this dissertation are devoted to a discussion of the East German reception of the films of Andrzej Wajda and Krzysztof Zanussi – two of Poland''s most important post-war directors.
95

Diagnóstico da pesca no litoral do Parque Nacional do Cabo Orange e sua área circundante, município de Oiapoque estado do Amapá

SILVA, Sirley Luzia de Figueiredo 19 March 2010 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2014-07-02T19:08:22Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_DiagnosticoPescaLitoral.pdf: 1486727 bytes, checksum: 49a20c034297b1ad1a24ba56e48fe023 (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-07-16T16:26:00Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_DiagnosticoPescaLitoral.pdf: 1486727 bytes, checksum: 49a20c034297b1ad1a24ba56e48fe023 (MD5) / Made available in DSpace on 2014-07-16T16:26:00Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_DiagnosticoPescaLitoral.pdf: 1486727 bytes, checksum: 49a20c034297b1ad1a24ba56e48fe023 (MD5) Previous issue date: 2010 / O estado do Amapá apresenta-se com 70 % dos seus 14.281.458,5 ha de extensão transformados em áreas protegidas, entres as várias categorias de Unidades de Conservação e terras indígenas, por sua vez, muitas dessas áreas adentras as águas litorâneas do atlântico, ora pelos seus limites, ora pelos seus entornos (área circundante), tornando conflitante a atividade pesqueira na linha da costa amapaense. O Acordo de Pesca assinado em 2007 entre pescadores do município do Oiapoque e gerencia do Parque Nacional do Cabo Orange (ICMBIO) busca o controle das pescarias pela frota do Oiapoque e diminuir conflito na faixa de 20 km em águas marinhas, que pertencem ao seu limite e área circundante. Este estudo investigou as características da pesca na região do estuário do rio Oiapoque, faixa marinha do Parque e sua área circundante. A metodologia contemplou entrevistas formais e informais de vários atores do setor pesqueiro no Oiapoque, monitoramento de 488 desembarques e viagens aos locais de pescarias. Foram obtidas as CPUE’s em função do rendimento por dia de pesca por pescador (Kg/dia/pesca para cada tipo de embarcação). Foram mapeados os pesqueiros considerados importantes e tradicionalmente explorados pela frota do Oiapoque, dentro dos limites do Parque Nacional do Cabo Orange e em sua área circundante. Os pescadores do município realizam pescarias de subsistência, artesanal de menor e maior escala. Por sua vez, são as pescarias artesanais de menor escala que predominam na área do parque particularmente as embarcações do tipo “barco de pequeno porte” (BPP), que se destacaram em número, cerca de 60 % das cadastradas na colônia. O volume de pescado desembarcado no município do Oiapoque foi 766 toneladas no ano de 2008. São principalmente alvo das pescarias a corvina (Cynoscion virescens) e a pescada branca (Plagioscion spp), desta capturada de pescarias de menor escala, principalmente em embarcações de capacidade até 1 tonelada do tipo barco motorizado (BOM). A produção é comercializada diretamente dos pescadores para intermediários (balanceiros) que por sua vez, vendem para o mercado local, os dois grandes centros consumidores do Amapá (Macapá e Santana) e para outros estados (Pará, São Paulo etc). / The state of Amapá comes with 70% of their 14.281.458,5 there is of extension transformed in protected areas, enter the several categories of Units of Conservation and indigenous lands, for his/her time, many of those areas penetrate the coastal waters of the Atlantic, some times for their limits, other times for their surrounding area, turning conflicting the fishing activity in the line of the coast of Amapá. The Agreement of Fishing signed in 2007 among fishermen of the municipal district of Oiapoque and it manages of Cabo Orange National Park (ICMBIO) it looks for the control of the fisheries for the fleet of Oiapoque and to reduce conflict in the strip of 20 km in sea waters, that you/they belong to his/her limit and surrounding area. This study investigated the characteristics of the fishing in the area of the estuary of the river Oiapoque, sea strip of the Park and his/her surrounding area. The methodology contemplated several actors' of the fishing section formal and informal interviews in Oiapoque, 488 disembarkation attendance and trips to the places of fisheries. They were obtained CPUE's in function of the income a day of fishing for fisherman (Kg/day/fishing for each boat type). The fishing ones were mapped considered important and traditionally explored by the fleet of Oiapoque, inside of the limits of Cabo Orange National Park and in his/her surrounding area. The fishermen of the municipal district accomplish subsistence fisheries, craft of minor and larger scale. For his/her time, they are the craft fisheries of smaller scale than they prevail in the area of the park particularly the embarkations of the type "boat of small load" (BPP), that you/they stood out in number, about 60% of the registered in the colony. The fish volume disembarked in the municipal district of Oiapoque was 766 tons in the year of 2008. They are mainly objective of the fisheries the corvina (Cynoscion virescens) and fished her white (Plagioscion spp), of this captured of fisheries of smaller scale, mainly in capacity embarkations to 1 ton of the type motorized boat (BOM). The production is marketed directly of the fishermen for middlemen (balanceiros) that for his/her time, they sell to the local market, the two great consuming centers of Amapá (Macapá and Santana) and for other states (Pará, São Paulo etc).
96

A categoria Modalidade em livros Didáticos de Língua Portuguesa e de Língua Francesa

Araújo, Alexandra Maria de Castro e Santos January 2011 (has links)
ARAÚJO, Alexandra Maria de Castro e Santos. A categoria Modalidade em livros Didáticos de Língua Portuguesa e de Língua Francesa. 2011,162f. Dissertação (Mestrado em Linguistica) – Universidade Federal do Ceará, Departamento de Letras Vernáculas, Programa de Pós-Graduação em Linguística, Fortaleza-CE, 2011. / Submitted by nazareno mesquita (nazagon36@yahoo.com.br) on 2012-06-25T15:16:40Z No. of bitstreams: 1 2011_diss_ AMCastro e Saraujo.pdf: 3328282 bytes, checksum: fe7eafd22cca32e78cd442b89ad4fe32 (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2013-10-10T13:55:24Z (GMT) No. of bitstreams: 1 2011_diss_ AMCastro e Saraujo.pdf: 3328282 bytes, checksum: fe7eafd22cca32e78cd442b89ad4fe32 (MD5) / Made available in DSpace on 2013-10-10T13:55:25Z (GMT). No. of bitstreams: 1 2011_diss_ AMCastro e Saraujo.pdf: 3328282 bytes, checksum: fe7eafd22cca32e78cd442b89ad4fe32 (MD5) Previous issue date: 2011 / O objetivo central desta pesquisa é analisar como a categoria Modalidade é abordada no estudo do Verbo, do Advérbio e do Adjetivo pelos Livros Didáticos de Língua Portuguesa e de Língua Francesa utilizados em escolas públicas do Ensino Fundamental II e do Ensino Médio, da cidade de Macapá, no estado do Amapá. Foram analisados 8 livros didáticos, sendo: 4 livros didáticos de Língua Portuguesa do Ensino Fundamental II, da coleção Projeto Araribá; 3 livros correspondentes ao Ensino Médio, da coleção Português: Linguagens e 1 livro de Língua Francesa, Portes Ouvertes [Portas Abertas], usado em todas as séries. Dos 4 livros de Língua Portuguesa do Ensino Fundamental selecionados, apenas os do 6º e 7º Anos apresentaram informações pertinentes às classes de palavras em análise, enquanto os demais, 8 e 9º Anos, apresentaram informações que dizem respeito às outras classes de palavras que não as utilizadas aqui nesta análise. Dos 3 livros de Língua Portuguesa do Ensino Médio, apenas o do 2º Ano tratou das classes de palavras em estudo, enquanto que os do 1º e 3º Anos abordaram informações relativas à interpretação de texto, à Literatura, não dando ênfase às estruturas gramaticais. Baseando-se no aparato teórico do Funcionalismo, elaborou-se um roteiro de análise, subdividido em três blocos, contendo questões referentes: a) ao Verbo (expressão da Modalidade; diferença entre Modo e Modalidade; associação dos Modos à certeza/incerteza/ordem ou correlação dos Modos ao contexto; efeitos de sentido; usos/funções dos verbos auxiliares modais; usos/funções de verbos de significação plena); b) ao Advérbio (expressão da Modalidade; tratamento da Modalidade em exercícios; expressão da Modalidade por palavras denotativas; apresentação dos advérbios em contextos de uso/textos; efeitos de sentido dos advérbios modais/modalizadores) e c) ao Adjetivo (efeito modalizador do uso de adjetivo em posição predicativa; comparação do uso do adjetivo em posição predicativa ao uso de outros recursos modais; efeitos de sentido em textos/contextos; explicação sobre diferentes meios/recursos de expressão da Modalidade, dentre os quais, o adjetivo). Os resultados mostram que os Livros Didáticos de Língua Portuguesa e de Língua Francesa, em seus conteúdos, não trabalham a categoria Modalidade, fazendo com que os alunos não tenham a oportunidade de refletir sobre a funcionalidade da língua em processo de interação discursiva. / L'objectif d e cette recherche est d'analyser comme la catégorie Modalité est abordée dans l'étu de du Verbe, d e l'Adverb e djectif par les manuels de la Langue Po rtugaise et d e la Langue Française utilisés d ans les écoles publiqu es Moyen, dans la ville de Macapa, l'État d'Amapá. Nous avons analy sé huit man uels, comme suit: quatre manu els de Langue Portugaise de l'Enseign ement Fond amen tal, d e la collection Projet Araribá ; trois livres liés à l'Enseignement Mo yen , de la collection Portug ais: Langages et un livre de la Langue Française, Portes Ouvertes , utilisé dans toutes les series. Des quatre livres d e Langue Portugaise sélection nés, seulement la sixième et la septième années ont présenté des info rmations relatives aux classes d e mots en cou rs d'an alyse, tandis q ue les autres, la huitième et la neuvième années ont p résenté des informations qui se rapp orten t à d'au tres classes de mots que ne sont pas utilisés ici, dans cette analyse. Parmi les trois livres p our la Lan gu e Portugaise de l'En seignement Moyen, seule la deuxième ann ée visée à des informations co ncernan tes aux classes de mots d ans cet étude, tandis que celles d u premier et d u troisième années on t recueilli les renseign ements relatifs à l'in terprétation des tex tes, à la Littératu re, ne mettant p as l'accent sur d es structu res gramaticaux . Sur l'appareil théorique du fonctionnalisme, a été étab li une feuille d e route pour l'an alyse, d iv isé en trois sections, contenant questio ns qu i se rapportent: a) au Verbe p armi Mode et Mod alité; modes à certitude/incertitude/ordre ou la co rrelation des Mo des au contex te; les effects du sens; les emp lo is/fonctions des verbes au xiliaires mo daux ; les emp lois/fonctions des verbes d e la Mo dalité; la Modalité en ex ercices; autres reco urs modaux ; les effects du sens en textes Modalité, p . Les résultats montrent que les manu els scolaires d e la Langue Portu gaise et d e la Langue Française, d ans leurs contenu s, ne travaillent pas la catégo rie Mod alité, afin q ue les étu diants ont l'occasion d e réf léchir sur les fonctio nnalités du langage dans le processus de l'interaction discursive.
97

The role of GAPDH in maintaining the functional state of the DNA repair enzyme APE1

Ayoub, Emily 08 1900 (has links)
Les sites apuriniques/apyrimidiniques (AP) sont des sites de l’ADN hautement mutagène. Les dommages au niveau de ces sites peuvent survenir spontanément ou être induits par une variété d’agents. Chez l’humain, les sites AP sont réparés principalement par APE1, une enzyme de réparation de l’ADN qui fait partie de la voie de réparation par excision de base (BER). APE1 est une enzyme multifonctionnelle; c’est une AP endonucléase, 3’-diestérase et un facteur redox impliqué dans l’activation des facteurs de transcription. Récemment, il a été démontré qu’APE1 interagit avec l’enzyme glycolytique GAPDH. Cette interaction induit l’activation d’APE1 par réduction. En outre, la délétion du gène GAPDH sensibilise les cellules aux agents endommageant l’ADN, induit une augmentation de formation spontanée des sites AP et réduit la prolifération cellulaire. A partir de toutes ces données, il était donc intéressant d’étudier l’effet de la délétion de GAPDH sur la progression du cycle cellulaire, sur la distribution cellulaire d’APE1 et d’identifier la cystéine(s) d’APE1 cible(s) de la réduction par GAPDH. Nos travaux de recherche ont montré que la déficience en GAPDH cause un arrêt du cycle cellulaire en phase G1. Cet arrêt est probablement dû à l’accumulation des dommages engendrant un retard au cours duquel la cellule pourra réparer son ADN. De plus, nous avons observé des foci nucléaires dans les cellules déficientes en GAPDH qui peuvent représenter des agrégats d’APE1 sous sa forme oxydée ou bien des focis de la protéine inactive au niveau des lésions d’ADN. Nous avons utilisé la mutagénèse dirigée pour créer des mutants (Cys en Ala) des sept cystéines d’APE1 qui ont été cloné dans un vecteur d’expression dans les cellules de mammifères. Nous émettons l’hypothèse qu’au moins un mutant ou plus va être résistant à l’inactivation par oxydation puisque l’alanine ne peut pas s’engager dans la formation des ponts disulfures. Par conséquent, on anticipe que l’expression de ce mutant dans les cellules déficientes en GAPDH pourrait restaurer une distribution cellulaire normale de APE1, libérerait les cellules de l’arrêt en phase G1 et diminuerait la sensibilité aux agents endommageant l’ADN. En conclusion, il semble que GAPDH, en préservant l’activité d’APE1, joue un nouveau rôle pour maintenir l’intégrité génomique des cellules aussi bien dans les conditions normales qu’en réponse au stress oxydatif. / Apurinic/apyrimidinic (AP) sites are highly mutagenic DNA lesions occurring either spontaneously or by the action of DNA damaging agents. In human cells, AP sites are processed by the major DNA repair enzyme APE1 through the base excision repair (BER) pathway. APE1 is a multifunctional protein that has AP endonuclease/3’-diesterase activities in addition to its role as a redox factor in activating many transcription factor. Recently, it has been shown that APE1 interacts with the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), an interaction that results in the activation of APE1 by reduction. Interestingly, depletion of GAPDH sensitized the cells to DNA damaging agents and induced an increase in spontaneous AP sites frequency. Moreover, cells knocked-down for GAPDH showed defects in proliferation. Here we set up to investigate the effects of GAPDH knockdown on cell cycle progression, APE1 subcellular localization and to identify the cysteine residue(s) of APE1, target(s) of GAPDH reduction. Our studies showed that GAPDH deficient cells arrested in G1 phase of the cell cycle. The defect in cell cycle progression is most probably due to accumulation of DNA damage which activates checkpoints leading to a delay in the cell cycle to allow DNA repair. Furthermore, in GAPDH deficient cells, APE1 formed nuclear foci-like structures that could represent aggregates of the oxidized form of APE1 or inactive APE1 foci on DNA lesions. Using site-directed mutagenesis, we created seven APE1 cysteine to alanine mutants which were cloned into a mammalian expression vector. We expect that at least one of these mutants is likely to resist the inactivation by oxidation as it cannot engage in disulfide bridge formation. Therefore, the expression of this mutant(s) in GAPDH knockdown cells is expected to restore a normal APE1 cellular distribution, rescue the cell cycle defects, and render the cells less sensitive to DNA damaging agents. In conclusion, our results show a new role of GAPDH in maintaining genomic stability under oxidative stress by maintaining APE1 in its functional state.
98

HBZ-induced functional deregulation of menin - new insights into the mechanism of telomerase activation during HTLV-1-mediated leukemogenesis / Dérégulation de la ménine par HBZ - un nouveau regard sur le mécanisme d'activation de la télomérase pendant la leucémogénèse induite par HTLV-1

Borowiak, Malgorzata 16 July 2013 (has links)
La leucémie T de l’adulte (ATL) est une pathologie lympho-proliférative aiguë associée à l’infection par le virus HTLV-1 (human T-cell leukemia virus type 1). La réactivation de la télomérase observée lors de la phase tardive du développement de l’ATL est un évènement crucial dans la progression tumorale. Elle est induite au niveau transcriptionnel par la protéine HBZ (HTLV-1 bZIP factor) et est dépendante du facteur de transcription JunD. Ce dernier est normalement associé en complexe avec le produit du gène suppresseur de tumeur MEN-1, la ménine, dont l’interaction avec JunD réprime la transcription JunD-dépendante et convertit JunD en inhibiteur de croissance.Mes résultats démontrent que la protéine virale HBZ inhibe la fonction suppresseur de tumeur de la ménine, induisant l’activité transcriptionnelle de JunD et donc l’activation de la transcription de son gène cible : la transcriptase inverse télomérase humaine (hTERT). J’ai démontré que HBZ, JunD et la ménine peuvent coexister dans un même complexe protéique et que HBZ et la ménine ont des effets opposés sur l’activité transcriptionnelle de JunD. En effet la ménine inhibe l’activation du promoteur proximal d’hTERT par JunD, alors que HBZ est capable de contre balancer cet effet. Finalement, je propose qu’en recrutant l’histone acétyltransférase p300, HBZ réverse la déacétylation des histones induite par le recrutement des HDACs par la ménine et par conséquent active le promoteur d’hTERT. L’ensemble de ces résultats a permis d’identifier les mécanismes moléculaires aboutissant à l’inhibition fonctionnelle de la protéine suppresseur de tumeur ménine, résultant en la dérégulation de la voie AP-1 dans les cellules infectées par HTLV-1. Finalement, ce travail apporte de nouvelles précisions sur le mécanisme de la surexpression transcriptionnelle de la télomérase lors de l’infection par HTLV-1, une étape importante de la mise en place et du développement de la leucémie T de l’adulte vers des stades plus agressifs. / Adult T-cell leukemia (ATL) is an aggressive lymphoproliferative disorder associated with human T-cell leukemia virus type 1 (HTLV-1) infection. Reactivation of telomerase, a critical event in tumor progression observed in late phases of ATL development, has been shown to be caused by HBZ (HTLV-1 bZIP factor), a regulatory protein encoded by the negative strand of the HTLV-1 genome. The HBZ-mediated up-regulation of the telomerase catalytic subunit is dependent on JunD, which in the cellular context occurs in the complex with menin, the product of the MEN-1 tumor suppressor gene. Interaction with menin represses JunD-dependent transcription and converts JunD into a growth suppressor, whereas it acts as a growth promoter in the absence of menin. My results demonstrate that the viral protein HBZ abrogates tumor suppressor function of menin, resulting in the activation of JunD transcriptional activity and finally in the up-regulation of its target gene, the human telomerase reverse transcriptase (hTERT). I showed that HBZ, JunD and menin can coexist in the same protein complex and that HBZ and menin exert opposite effects on JunD transcriptional activity. Moreover menin inhibits the JunD-mediated activation of the hTERT proximal promoter and HBZ is able to counteract this effect. Finally, I proposed that HBZ, by recruiting p300 histone acetyltransferase, reverses the histone deacetylation conducted by menin-recruited HDACs and therefore up-regulates the expression of the hTERT gene. Altogether, my work led to the identification of the molecular mechanism leading to the functional impairment of the menin tumor suppressor, which results in the deregulation of AP-1 signaling in HTLV-1 infected cells. Finally this work gave new insights into the mechanism of the transcriptional up-regulation of the hTERT gene upon HTLV-1 infection, being a key event during the development of Adult T-cell leukemia and a necessary step towards the progression into more aggressive courses.
99

Efeitos de ACTH, PMA e dcAMP na expressão de genes das famílias FOS e JUN do gene C-MYC e na atividade do fator de transcrição AP-1 em células adrenocorticais Y-1. / Effects of ACTH, PMA and dcAMP on fos, jun and c-myc gene expression and AP-1 transcription factor activity control in Y-1 adrenocortical cells

Lepique, Ana Paula 04 November 1996 (has links)
As células Y-1 pertencem a uma linhagem clonal de células funcionais de córtex adrenal de camundongo, que respondem a ACTH. Em células Y-1, ACTH promove a esteroidogênese (função) e tem efeitos regulatórios complexos na transição G0→G1→S do ciclo celular. ACTH promove a transição G0→G1, mas inibe a transição G1→S. É possível que a regulação do ciclo celular por ACTH seja mediada pelo controle da expressão dos proto-oncogenes das famílias fos, jun e myc. Nosso laboratório mostrou, anteriormente, que ACTH induz a expressão dos genes fos e jun, mas inibe c-myc. O objetivo deste trabalho foi identificar pontos de controle na expressão dos genes fos, jun e myc e na atividade dos fatores de transcrição AP-1 (dímeros da proteínas Fos e Jun) por ACTH, derivados de cAMP (ativadores de PKA), PMA (ativador de PKC) e FCS (soro fetal bovino). ACTH, PMA e dcAMP aumentam a atividade de ligação de AP-1 a DNA, independentemente de síntese protéica. Ensaios de elongação de cadeia nascente de RNA (run off transcription) mostram que ACTH, PMA e FCS são fortes indutores de c-fos, c-jun e junB, enquanto dcAMP induz apenas c-fos e junB. Hibridizações Northern permitiram estimar a meia-vida dos mRNAs de c-fos e c-jun em 30 min, independentemente do tratamento com ACTH ou PMA. Diferentemente de c-fos, o mRNA de fosB é superinduzido por ActinomicinaD em células Y-1 tratadas com ACTH e PMA. / The Y-1 cells belong to a clonal lineage of functional mouse adrenocortical cells, which are responsive to ACTH. In Y-1 cells, ACTH promotes esteroidogenesis (function) and has complex effects on the G0→G1→S transition of the Y-1 cell cycle. ACTH induces the G0→G1 transition but inhibits the G1+S transition. Probably, the cell cycle regulation by ACTH is mediated by the expression control of the proto-oncogenes from the fos, jun and myc families. Our laboratory has previously shown that ACTH induces the fos and jun genes expression, but inhibits c-myc expression. The target of this work was to identify control points in the fos, jun and myc genes expression and in the AP-1 transcription factors (Fos and Jun proteins dimers) by ACTH, cAMP derivatives (PKA activators), PMA (PKC activator) and FCS (Fetal Calf Serum). ACTH, PMA and dcAMP raise the AP-1 DNA binding activity, independently of protein synthesis. Run off transcription assays show that ACTH, PMA and FCS are strong c-fos, c-jun and junB inducers, while dcAMP induces only c-fos and junB. Northern hybridisations allowed us to estimate the half life of the fos and jun mRNAs in about 30 min, independently of ACTH or PMA treatment. Differently of c-fos, fosB mRNA is superinduced by ActinomicinD treatment in Y-1 cells treated with ACTH or PMA.
100

Function of Fra1 in mesenchymal stromal cell differentiation & the potential immune modulatory role of Fra1

Drießler, Frank 06 August 2008 (has links)
Aktivator Protein-1 (AP-1) ist ein kollektiver Terminus für dimerische Transkriptionsfaktoren, die sich aus Fos- und Jun- Proteinen zusammensetzen. Diese Untereinheiten binden an eine gemeinsame, spezifische DNA-Sequenz, die AP-1 Bindungsstelle. Zusätzlich zu der gut dokumentierten Rolle des c-Fos Proteins in der Tumorgenese, wo dieses Gen als ein Aktivator beschrieben ist, übt AP-1 einen Einfluss auf mesenchymale Stromazellen und Immunzellen aus. Mesenchymale Knochenmarkszellen sind die Vorläuferzellen für Adipozyten, Osteoblasten, Chondrozyten, Myozyten und Fibroblasten. Die molekularen Mechanismen, welche die Differenzierungen regeln, sind noch weitgehend unerforscht. Der heterodimere Transkriptionsfaktor AP-1 übt eine wichtige Rolle in der Kontrolle der Zelldifferenzierung aus. Verschieden genetisch veränderte Mausmodelle untermauerten dies. Mäuse, welche das Fos-related antigen-1 (Fra1) oder eine kürzere Protein-Isoform von FosB (deltaFosB) überexpremieren, entwickelten, durch eine beschleunigte Differenzierung der Osteoblasten, eine Osteosklerose. Interessanterweise konnte gezeigt werden, dass die transgenen deltaFosB Mäuse weniger Fett haben. Die Stabilität und Aktivität von Fos Proteinen kann durch post-transkriptionale Modifizierungen geregelt werden. Basierend auf knockout Mausmodellen, wurde eine tragende Rolle für das wachstumsregulierende Enzym Rsk2 postuliert. Rsk2 spielt eine mögliche Rolle bei der Ausdifferenzierung von mesenchymalen Vorläuferzellen zu Osteoblasten und Adipozyten. Das Ziel dieser Arbeit war es molekulare Mechanismen zu finden, welche die unterschiedlichen Phänotypen (wild typ, fra1-tg, rsk2-defizient und fra1-tg/rsk2-defizient) charakterisieren. Die Knochenuntersuchungen der verschiedenen Genotypen zeigten, dass Fra1 und Rsk2, unabhängig voneinander, tragende Rollen im Knochenmetabolismus spielen. Quantitative Analysen von Adipozytenmarker, wie PPARgamma und C/EBPalpha zeigten, dass das Protein Fra1 die Adipozytenreifung in vivo und in vitro reguliert. Zusätzlich entwickelten die „doppel-mutierten“ fra1-tg/rsk2-/y Mäuse einen Lipodystrophy. Ein milderer Phänotyp wurde in den fra1-tg Tieren beobachtet, jedoch nicht in den Rsk2-knockout Mäusen. Zusätzlich wurde beobachtet, dass mesenchymale Zellen, welche Fra1 überexprimieren, gegen Glucocorticoid-induzierte Wachstumshemmung resistent waren. Diese Wirkung kann am wahrscheinlichsten durch die Fra1-vermittelte Suppression des Glucocorticoidrezeptors erklärt werden. Außerdem beeinflusste die Überexpression von Fra1 die Milzentwicklung. Leber und Herzanalysen zeigten, dass Fra1 kollagenhaltiges Gewebe induziert. Krankheiten wie Cholangitis und Fibrosen waren die Folge. / AP-1 transcription factor is a general name for multiple dimers formed by the association of Fos (or ATF) and Jun proteins. AP-1 acts as a sensor of changes in the cellular environment and thus, it is implicated in the modulation of cell proliferation, differentiation, transformation and cell death. Besides the well-documented role of c-Fos protein in oncogenesis, where this gene can function as a tumor promoter, AP-1 proteins are being recognized as regulators for mesenchymal stromal cell development and as regulators of immune cells. The mesenchymal stromal cells are the common progenitors for various mesenchymal lineages such as adipocytes, osteoblasts, chondrocytes, myocytes and fibroblasts. AP-1 seems to play a key role in the control of mesenchymal cell fate decision and differentiation. This is suggested by phenotypes of mice with a genetic modifications in either the Jun or the Fos component of AP-1. In particular, mice overexpressing the Fos-related antigen-1 (Fra1) or the short isoform of FosB (deltaFosB) have been found to develop osteosclerosis due to an accelerated differentiation of osteoblasts. Interestingly, mice overexpressing deltaFosB also developed less fat tissue. The activity of Fos proteins can be regulated by post-transcriptional modification. Based on knockout mouse model, a role for the growth factor regulated kinase Rsk2 was proposed in the differentiation of mesenchymal stromal cells to osteoblasts as well as in fat tissue development. Goal in this study was to identify the molecular mechanisms explaining the differences between the wild type, fra1-tg, rsk2-deficient and fra1-tg/rsk2-deficient phenotypes. The comparison of the bones of the different mice genotypes revealed, that Fra1 and Rsk2 were independently regulating bone metabolism. Quantitative analysis of adipocyte markers expressions, like PPARgamma and C/EBPalpha revealed, that Fra1 overexpression was blocking adipocyte maturation in vivo and in vitro. Moreover, the in vivo results show that the fra1-tg/rsk2-/y mice develop a severe lipodystrophy. A milder phenotype was observed in the parental fra1-tg strain but not in the Rsk2 knockout strain. Additionally, it was been observed, that mesenchymal cells overexpressing Fra1 were resistant to glucocorticoid-induced growth inhibition. This effect can most likely be explained by Fra1-mediated downregulation of the glucocorticoid receptor. Furthermore, Fra1 overexpression influenced spleen development. Liver and heart analyses showed that Fra1 overexpression induced collagen tissue. Diseases like cholangitis and fibrosis were the outcome.

Page generated in 0.0468 seconds