{"id":95633,"date":"2018-03-11T10:15:41","date_gmt":"2018-03-11T10:15:41","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/the-effects-of-altered-dna-topoisomerase-levels-on-the-transcriptome-of-saccharomyces-cerevisiae\/"},"modified":"2018-03-11T10:15:41","modified_gmt":"2018-03-11T10:15:41","slug":"the-effects-of-altered-dna-topoisomerase-levels-on-the-transcriptome-of-saccharomyces-cerevisiae","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/barcelona\/the-effects-of-altered-dna-topoisomerase-levels-on-the-transcriptome-of-saccharomyces-cerevisiae\/","title":{"rendered":"The effects of altered dna topoisomerase levels on the transcriptome of saccharomyces cerevisiae"},"content":{"rendered":"<h2>Tesis doctoral de <strong> Ricky S. Joshi <\/strong><\/h2>\n<p>Durante la transcripci\u00f3n del adn, se acumula tensi\u00f3n helicoidal positiva (+) en el frente de avance de la maquinaria transcripcional y tensi\u00f3n helicoidal negativa (-) detr\u00e1s. En la replicaci\u00f3n, hay tambi\u00e9n una producci\u00f3n de tensi\u00f3n helicoidal positiva en el frente de avance de la horquilla de replicaci\u00f3n. Las topoisomerasas de adn son enzimas que producen cortes transitorios en una o en las dos cadenas del adn d\u00faplex, para resolver encademientos y para modular la tensi\u00f3n helicoidal del adn. Topo i y topo ii relajan la tensi\u00f3n helicoidal positiva (+) y negativa (-). En esta tesis, me propongo estudiar el efecto de las dosis alteradas de estas dos enzimas en el transcriptoma de saccharomyces cerevisiae a trav\u00e9s de la tecnolog\u00eda de microarrays de adn.  en el transcurso del trabajo, se observ\u00f3 que las topoisomerases no fueron capaces de compensar la una la deficiencia de la otra al nivel de arnm, en c\u00e9lulas con un desequilibrio de la dosis normal de topoisomerasas. Tambi\u00e9n se vio que topo i y ii tenian funciones distintas en la transcripci\u00f3n: topo i era m\u00e1s importante para los transcritos peque\u00f1os y con una tasa de transcripci\u00f3n alta, mientras que la topo ii era m\u00e1s relevante para la transcripcion de genes largos  (mayores de 3 kb). Tambi\u00e9n se estudi\u00f3 el efecto de la acumulaci\u00f3n de tensi\u00f3n helicoidal positiva en el transcriptoma de levadura. Se observ\u00f3 una parada global de la transcripci\u00f3n que afect\u00f3 a los genes a una distancia de 50 kb del extremo de la cromosoma (regi\u00f3n distal del telomero). Sin embargo, los genes situados en torno a 50 kb del extremo proximal no parec\u00edan afectados  por  la acumulaci\u00f3n de la tensi\u00f3n helicoidal positiva.  este efecto de parada de la transcripci\u00f3n en esta region no se debi\u00f3 al silenciamiento telom\u00e9rico como que se vio en cepas delta sir3. Creemos que los genes situados en la regi\u00f3n pr\u00f3xima al tel\u00f3mero escapan esta parada de la transcripci\u00f3n debido a la disipaci\u00f3n de la tensi\u00f3n helicoidal del adn en los extremos de la cromosoma, demostrando que pueden girar libremente. Esta rotaci\u00f3n reduce la tensi\u00f3n de adn s\u00f3lo hasta 50 kb del extremo, donde la parada en la iniciaci\u00f3n de la transcripci\u00f3n empieza a tener efecto siendo pr\u00e1cticamente completa a 100kb. En regiones mas distantes del tel\u00f3mero, la tensi\u00f3n helicoidal no puede ser reducida por el gran volumen de adn super-enrollado que le impide  superar las fuerzas de fricci\u00f3n celular, por lo tanto, las polimerasas de arn tienen una dificultad espacial para acoplarse al adn y la iniciacion de transcripci\u00f3n no tiene lugar. Proponemos que el adn existe como un \u00fanico dominio topol\u00f3gico en el que los extremos de los cromosomas son libres a girar.<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>The effects of altered dna topoisomerase levels on the transcriptome of saccharomyces cerevisiae<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 The effects of altered dna topoisomerase levels on the transcriptome of saccharomyces cerevisiae <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Ricky S. Joshi <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Barcelona<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 24\/07\/2009<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Direcci\u00f3n y tribunal<\/h3>\n<ul>\n<li><strong>Director de la tesis<\/strong>\n<ul>\n<li>Joaquim Roca  Bosch<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: ferran Azorin marin <\/li>\n<li>roger Gomis cabre (vocal)<\/li>\n<li>  (vocal)<\/li>\n<li>  (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Ricky S. Joshi Durante la transcripci\u00f3n del adn, se acumula tensi\u00f3n helicoidal positiva (+) en el frente [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[951],"tags":[13691,40207,196651,56834],"class_list":["post-95633","post","type-post","status-publish","format-standard","hentry","category-barcelona","tag-ferran-azorin-marin","tag-joaquim-roca-bosch","tag-ricky-s-joshi","tag-roger-gomis-cabre"],"_links":{"self":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/95633","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/comments?post=95633"}],"version-history":[{"count":0,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/95633\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/media?parent=95633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/categories?post=95633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/tags?post=95633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}