Video Experimental Relacionado
Updated: May 23, 2026
09:22
Rapid Synthesis and Screening of Chemically Activated Transcription Factors with GFP-based Reporters
Published on: November 26, 2013
La pérdida de nucleosomas activa los promotores aguas abajo de la levadura in vivo
1Molecular Biology Institute, University of California, Los Angeles 90024.
Cell
|December 23, 1988
Resumen
La adición de glucosa a la levadura causa el agotamiento de los nucleosomas, activando los elementos promotores aguas abajo. Esta pérdida de nucleosomas mejora la iniciación y el alargamiento de la transcripción génica, incluso sin secuencias de activadores aguas arriba.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética de la levadura Genética de la levadura
- Reglamento genético Reglamento genético.
Sus antecedentes:
- Los nucleosomas juegan un papel crítico en la regulación de la accesibilidad y transcripción de los genes.
- Comprender cómo la estructura de la cromatina afecta la expresión génica es fundamental para la biología molecular.
- El sistema promotor de GAL en la levadura proporciona una poderosa herramienta para controlar la expresión génica y la dinámica de la cromatina.
Objetivo del estudio:
- Para investigar el impacto del agotamiento del nucleosoma en la actividad de los elementos promotores aguas abajo en la levadura.
- Para determinar si la pérdida de nucleosomas puede activar promotores independientemente de las secuencias reguladoras canónicas aguas arriba.
- Aclarar el papel del agotamiento del nucleosoma en la iniciación y elongación de la transcripción.
Principales métodos:
- Utilizando cepas de levadura con el gen histona H4 bajo control del promotor GAL.
- Inducir el agotamiento de los nucleosomas a través de la adición de glucosa.
- Evaluación de la activación de elementos promotores aguas abajo (caja TATA, región I) de promotores de levadura (PHO5, CYC1, GAL1) fusionados con el gen lacZ de E. coli.
- Analizando la actividad del promotor con y sin secuencias de activador aguas arriba (UAS).
Principales resultados:
- El agotamiento del nucleosoma, inducido por la glucosa, activa los elementos promotores aguas abajo de PHO5, CYC1 y GAL1.
- El elemento aguas abajo PHO5 se activa por la pérdida de nucleosomas independientemente de la presencia de UAS.
- La eliminación de elementos UAS en los promotores CYC1 y GAL1 aún da como resultado la activación de los promotores aguas abajo restantes en la pérdida de nucleosomas mediada por la glucosa.
- Estos hallazgos indican que la pérdida de nucleosomas mejora la iniciación y el alargamiento de la transcripción in vivo.
Conclusiones:
- El agotamiento de los nucleosomas es un factor significativo en la activación de la transcripción génica en levaduras.
- Los elementos promotores aguas abajo pueden ser activados por la pérdida de nucleosomas, lo que sugiere un papel directo en la iniciación de la transcripción.
- Las proteínas que reconocen a los promotores aguas abajo permanecen funcionales, al menos parcialmente, incluso sin la formación de complejos mediados por UAS.
Más Videos Relacionados
09:21Saccharomyces cerevisiae Metabolic Labeling with 4-thiouracil and the Quantification of Newly Synthesized mRNA As a Proxy for RNA Polymerase II Activity
Published on: October 22, 2018
06:53In Vivo Monitoring of Transcriptional Activity During Metabolic Transition Using a Bioluminescent Reporter in Yeast
Published on: February 21, 2025
Videos de Conceptos Relacionados
01:28Yeast Signaling
Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
02:36RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
02:40The Eukaryotic Promoter Region
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
01:52Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
02:40The Eukaryotic Promoter Region
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...