{"id":111442,"date":"2018-03-11T10:37:56","date_gmt":"2018-03-11T10:37:56","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/estudio-de-los-cambios-topologicos-que-experimenta-el-dna-durante-la-replicacion\/"},"modified":"2018-03-11T10:37:56","modified_gmt":"2018-03-11T10:37:56","slug":"estudio-de-los-cambios-topologicos-que-experimenta-el-dna-durante-la-replicacion","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/biologia-molecular\/estudio-de-los-cambios-topologicos-que-experimenta-el-dna-durante-la-replicacion\/","title":{"rendered":"Estudio de los cambios topol\u00f3gicos que experimenta el dna durante la replicaci\u00f3n"},"content":{"rendered":"<h2>Tesis doctoral de <strong> Virginia Lopez Martinez <\/strong><\/h2>\n<p>Durante la replicaci\u00f3n del dna, los intermediarios de replicaci\u00f3n (ris) sufren cambios topol\u00f3gicos que afectan al superenrollamiento, encadenamiento y anudamiento. Los nudos en el dna tienen consecuencias delet\u00e9reas y deben ser eliminados; por ello el papel del anudamiento de las crom\u00e1tidas hermanas in vivo en procariotas continua siendo un misterio. Para estudiar esos nudos inter-crom\u00e1tida y tratar de identificar la enzima responsable de anudar las crom\u00e1tidas hermanas, construimos pl\u00e1smidos de escherichia coli con barreras para el avance de la horquilla de replicaci\u00f3n. La electroforesis bidimensional en geles de agarosa junto con la microscop\u00eda de fuerza at\u00f3mica nos permiti\u00f3 confirmar la naturaleza de las mol\u00e9culas identificadas como ris anudados. En procariotas, la topoisomerasa iv (topo iv) es la encargada de desanudar el dna. Nuestro resultados apuntan a un posible papel dual de la topo iv en el anudamiento: esta enzima ser\u00eda tambi\u00e9n la responsable de crear los nudos inter- e intra-crom\u00e1tidas durante la replicaci\u00f3n. Proponemos un modelo seg\u00fan el cual en la regi\u00f3n ya replicada algunos de los pases de hebra catalizados por la topo iv atrapar\u00edan cruces de pre-encadenamiento que conducir\u00edan a la formaci\u00f3n de nudos. Tambi\u00e9n analizamos el desencadenamiento de las crom\u00e1tidas hermanas por la topoisomerasa ii (top2) en eucariotas, para dilucidar si los cambios topol\u00f3gicos en el dna producidos durante la mitosis favorecen dicho proceso. Para ello estudiamos los cambios topol\u00f3gicos de un minicromosoma circular a lo largo del ciclo de divisi\u00f3n en saccharomyces cerevisiae. Nuestros resultados muestran que, al paso de las c\u00e9lulas por mitosis, los minicromosomas experimentan un cambio topol\u00f3gico dr\u00e1stico a modo de superenrollamiento positivo que requiere del huso mit\u00f3tico y de la condensina smc2. El desencadenamiento es un proceso crucial para la vida celular pero se desconoce c\u00f3mo tiene lugar. Nuestro trabajo profundiza en la comprensi\u00f3n de este fen\u00f3meno pues demuestra que el superenrollamiento positivo en mol\u00e9culas encadenadas maximiza el desencadenamiento de las crom\u00e1tidas hermanas por parte de la top2.<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>Estudio de los cambios topol\u00f3gicos que experimenta el dna durante la replicaci\u00f3n<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 Estudio de los cambios topol\u00f3gicos que experimenta el dna durante la replicaci\u00f3n <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Virginia Lopez Martinez <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Aut\u00f3noma de Madrid<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 18\/10\/2011<\/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>Jorge  Bernardo Schvartzman Blinder<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: margarita Salas falgueras <\/li>\n<li>david Santamar\u00eda velilla (vocal)<\/li>\n<li>enrique Viguera m\u00ednguez (vocal)<\/li>\n<li>Ana Losada valiente (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Virginia Lopez Martinez Durante la replicaci\u00f3n del dna, los intermediarios de replicaci\u00f3n (ris) sufren cambios topol\u00f3gicos que [&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 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