Search results for "transcripció"
showing 10 items of 45 documents
The cellular growth rate controls overall mRNA turnover, and modulates either transcription or degradation rates of particular gene regulons
2015
We analyzed 80 different genomic experiments, and found a positive correlation between both RNA polymerase II transcription and mRNA degradation with growth rates in yeast. Thus, in spite of the marked variation in mRNA turnover, the total mRNA concentration remained approximately constant. Some genes, however, regulated their mRNA concentration by uncoupling mRNA stability from the transcription rate. Ribosome-related genes modulated their transcription rates to increase mRNA levels under fast growth. In contrast, mitochondria-related and stress-induced genes lowered mRNA levels by reducing mRNA stability or the transcription rate, respectively. We also detected these regulations within th…
Defects in the NC2 repressor affect both canonical and non-coding RNA polymerase II transcription initiation in yeast.
2016
BACKGROUND: The formation of the pre-initiation complex in eukaryotic genes is a key step in transcription initiation. The TATA-binding protein (TBP) is a universal component of all pre-initiation complexes for all kinds of RNA polymerase II (RNA pol II) genes, including those with a TATA or a TATA-like element, both those that encode proteins and those that transcribe non-coding RNAs. Mot1 and the negative cofactor 2 (NC2) complex are regulators of TBP, and it has been shown that depletion of these factors in yeast leads to defects in the control of transcription initiation that alter cryptic transcription levels in selected yeast loci. RESULTS: In order to cast light on the molecular func…
The SAGA/TREX‑2 subunit Sus1 binds widely to transcribed genes and affects mRNA turnover globally
2018
Abstract Background Eukaryotic transcription is regulated through two complexes, the general transcription factor IID (TFIID) and the coactivator Spt–Ada–Gcn5 acetyltransferase (SAGA). Recent findings confirm that both TFIID and SAGA contribute to the synthesis of nearly all transcripts and are recruited genome-wide in yeast. However, how this broad recruitment confers selectivity under specific conditions remains an open question. Results Here we find that the SAGA/TREX-2 subunit Sus1 associates with upstream regulatory regions of many yeast genes and that heat shock drastically changes Sus1 binding. While Sus1 binding to TFIID-dominated genes is not affected by temperature, its recruitmen…
Transcriptional Response of Saccharomyces cerevisiae to Different Nitrogen Concentrations during Alcoholic Fermentation▿ †
2007
Gene expression profiles of a wine strain of Saccharomyces cerevisiae PYCC4072 were monitored during alcoholic fermentations with three different nitrogen supplies: (i) control fermentation (with enough nitrogen to complete sugar fermentation), (ii) nitrogen-limiting fermentation, and (iii) the addition of nitrogen to the nitrogen-limiting fermentation (refed fermentation). Approximately 70% of the yeast transcriptome was altered in at least one of the fermentation stages studied, revealing the continuous adjustment of yeast cells to stressful conditions. Nitrogen concentration had a decisive effect on gene expression during fermentation. The largest changes in transcription profiles were o…
Identificación y caracterización de factores implicados en la biogénesis de la RNA polimerasa II en Saccharomyces cerevisiae
2014
INTRODUCCIÓN La transcripción es el proceso de síntesis enzimática de un RNA a partir de una secuencia complementaria de DNA. En eucariotas, la transcripción de los genes que codifican proteínas la lleva a cabo la RNA polimerasa II (RNA pol II), junto con una gran cantidad de factores auxiliares que participan en el proceso actuando a diferentes niveles. Para que la RNA pol II inicie la transcripción se requiere la formación del complejo pre-inicio (PIC). Uno de los pasos clave en la regulación del inicio de la transcripción es la formación del PIC. En este proceso se ha visto implicado el regulador transcripcional NC2 (cofactor negativo 2), que actúa bloqueando el ensamblaje del PIC. Ademá…
La transcripción del lenguaje afásico
2004
En el presente artículo reflexionamos sobre las necesidades que se plantean en la transcripción de un corpus de lenguaje oral procedente de hablantes afásicos; estas reflexiones surgen a propósito de la elaboración del corpus PerLA (Percepción y Lenguaje Afásico).Se revisan los sistemas de trancripción del Análisis conversacional, del proyectos CHILDES y del SALT, señalando sus ventajas e inconvenientes para este tipo de datos.
Respuesta de las Levaduras al Estrés Osmótico causado por Elevadas Concentraciones de Glucosa: Función de las proteínas Hgi1 y Hot1
2015
El éxito de supervivencia de un organismo está vinculado a su habilidad para adaptarse a los cambios que suceden a su alrededor. La levadura S. cerevisiae posee mecanismos para hacer frente a las situaciones desfavorables de estrés, existiendo una respuesta común, dirigida por el factor transcripcional Msn2/4, que se activa rápidamente e independientemente del agente causante del estrés. Msn2/4 afecta a la expresión de aproximadamente 900 genes y está a su vez regulado por las vías PKA y TOR, que controlan el crecimiento celular en función de la disponibilidad de nutrientes. Además de esta respuesta común, la levadura posee mecanismos para hacer frente a las situaciones particulares de estr…
Regulon-Specific Control of Transcription Elongation across the Yeast Genome
2009
Transcription elongation by RNA polymerase II was often considered an invariant non-regulated process. However, genome-wide studies have shown that transcriptional pausing during elongation is a frequent phenomenon in tightly-regulated metazoan genes. Using a combination of ChIP-on-chip and genomic run-on approaches, we found that the proportion of transcriptionally active RNA polymerase II (active versus total) present throughout the yeast genome is characteristic of some functional gene classes, like those related to ribosomes and mitochondria. This proportion also responds to regulatory stimuli mediated by protein kinase A and, in relation to cytosolic ribosomal-protein genes, it is medi…
Nucleo-cytoplasmic shuttling of RNA-binding factors: mRNA buffering and beyond.
2022
Gene expression is a highly regulated process that adapts RNAs and proteins content to the cellular context. Under steady-state conditions, mRNA homeostasis is robustly maintained by tight controls that act on both nuclear transcription and cytoplasmic mRNA stability. In recent years, it has been revealed that several RNA-binding proteins (RBPs) that perform functions in mRNA decay can move to the nucleus and regulate transcription. The RBPs involved in transcription can also travel to the cytoplasm and regulate mRNA degradation and/or translation. The multifaceted functions of these shuttling nucleo-cytoplasm RBPs have raised the possibility that they can act as mRNA metabolism coordinator…
The Saccharomyces cerevisiae Hot1p regulated gene YHR087W (HGI1) has a role in translation upon high glucose concentration stress.
2012
Abstract Background While growing in natural environments yeasts can be affected by osmotic stress provoked by high glucose concentrations. The response to this adverse condition requires the HOG pathway and involves transcriptional and posttranscriptional mechanisms initiated by the phosphorylation of this protein, its translocation to the nucleus and activation of transcription factors. One of the genes induced to respond to this injury is YHR087W. It encodes for a protein structurally similar to the N-terminal region of human SBDS whose expression is also induced under other forms of stress and whose deletion determines growth defects at high glucose concentrations. Results In this work …