Regulation of transcriptional activation in response to heat stress and osmostress
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Document Type
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Author
Director
Nadal Clanchet, Eulàlia de
Posas Garriga, Francesc
Posas Garriga, Francesc
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Publication Date
Pages
204 p.
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Citation
Ruiz Roig, C. Regulation of transcriptional activation in response to heat stress and osmostress. Universitat Pompeu Fabra; 2011. handle: http://hdl.handle.net/10803/81712
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Doctoral program
Programa de doctorat en Biomedicina
Abstract
A Saccharomyces cerevisiae, un increment de la temperatura comporta diversos efectes deleteris en l’organització interna de la cèl∙lula i indueix una inducció ràpida, massiva i transitòria d’expressió gènica, que es controla principalment pels factors de transcripció Hsf1 i Msn2/4. En aquest estudi, fent servir un crivatge genètic a gran escala, hem identificat el conjunt d’activitats que es requereixen per a l’adaptació cel∙lular a l’estrés tèrmic. A més, hem trobat que el complex de desacetilació d’histones de Rpd3 és un component essencial per a l’adaptació i la supervivència a l’estrés tèrmic, i que es requereix per a l’adequada regulació de l’expressió gènica. Concretament, Rpd3 es necessita per a l’activació dels gens depenents de Msn2/4 en resposta a estrés tèrmic. A més, hem trobat que és el complex gran de Rpd3, però no el petit, el qui media l’adaptació cel∙lular. Un increment en l’osmolaritat externa activa la quinasa activada per estrés (SAPK) Hog1, que és essencial per induir diverses respostes adaptatives, com la regulació de l’expressió gènica. Hog1 controla al menys cinc factors de transcripció. Aquí ensenyem que els factors de transcripció Rtg1 i Rtg3 regulen l’expressió d’un conjunt de gens en resposta a estrés osmòtic, d’una manera depenent de Hog1. En resposta a estrés osmòtic, Hog1 es requereix per a l’acumulació nuclear del complex de transcripció de Rtg1/3. Un cop al nucli, Hog1 es recluta als promotors i la seva activitat es requereix per a la unió de Rtg1/3 a la cromatina. A més, la fosforilació de Rtg3 per Hog1 és un pas important per a l’adequada activació transcripcional.
In Saccharomyces cerevisiae, increases in temperature lead to deleterious effects on the internal organization of the cell, and lead to a massive and transient induction of gene expression, mainly controlled by Hsf1 and Msn2/4 transcription factors. In this study, by using a genome‐wide genetic screen, we identified the network of essential activities required for cell adaptation to heat stress. Moreover, we found that the Rpd3 histone deacetylase (HDAC) complex is an essential component for adaptation and survival to heat stress and it is required for proper regulation of gene expression. Specifically, Rpd3 is needed for activation of the Msn2/4‐dependent genes in response to heat stress. Moreover, we found that the large, but not the small Rpd3 complex mediates cell adaptation. Increases in the extracellular osmolarity activate the Hog1 stress‐activated protein kinase (SAPK), which is essential for the induction of diverse osmoadaptive responses, such as regulation of gene expression. At least five transcription factors have been shown to be controlled by Hog1. Here we show that the Rtg1 and Rtg3 transcription factors regulate the expression of a set of genes upon osmostress in a Hog1‐dependent manner. In response to osmostress, Hog1 is required for the nuclear accumulation of the Rtg1/3 transcription complex. Once in the nucleus, Hog1 is recruited at promoters and its activity is required for the binding of Rtg1/3 to chromatin. Moreover, Rtg3 phosphorylation by Hog1 is an important step for proper transcriptional activation.
In Saccharomyces cerevisiae, increases in temperature lead to deleterious effects on the internal organization of the cell, and lead to a massive and transient induction of gene expression, mainly controlled by Hsf1 and Msn2/4 transcription factors. In this study, by using a genome‐wide genetic screen, we identified the network of essential activities required for cell adaptation to heat stress. Moreover, we found that the Rpd3 histone deacetylase (HDAC) complex is an essential component for adaptation and survival to heat stress and it is required for proper regulation of gene expression. Specifically, Rpd3 is needed for activation of the Msn2/4‐dependent genes in response to heat stress. Moreover, we found that the large, but not the small Rpd3 complex mediates cell adaptation. Increases in the extracellular osmolarity activate the Hog1 stress‐activated protein kinase (SAPK), which is essential for the induction of diverse osmoadaptive responses, such as regulation of gene expression. At least five transcription factors have been shown to be controlled by Hog1. Here we show that the Rtg1 and Rtg3 transcription factors regulate the expression of a set of genes upon osmostress in a Hog1‐dependent manner. In response to osmostress, Hog1 is required for the nuclear accumulation of the Rtg1/3 transcription complex. Once in the nucleus, Hog1 is recruited at promoters and its activity is required for the binding of Rtg1/3 to chromatin. Moreover, Rtg3 phosphorylation by Hog1 is an important step for proper transcriptional activation.
Keywords
Heat stress, Osmostress, Chromatin, Transcription, Deacetylase, Rpd3, MAPK, Hog1, Mitochondrion, Rtg1/3, Estrés tèrmic, Estrés osmòtic, Cromatina, Transcripció, Desacetilasa, Mitocòndria
Subjects
576 - Cellular and subcellular biology. Cytology
Publisher
Universitat Pompeu Fabra
