Video Experimental Relacionado

Updated: Jul 17, 2026

Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro

Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro

Published on: May 3, 2014

Recorrido de reciclaje facilitado para la ARN polimerasa III

G Dieci¹, A Sentenac

¹Service de Biochimie et Génétique Moléculaire Commissariat à l'Energie Atomique-Saclay, Gif-sur-Yvette, France.

|January 26, 1996

Resumen

La ARN polimerasa III (pol III) de la levadura logra una alta eficiencia de transcripción a través del reciclaje rápido, no sólo la iniciación. Esta polimerasa se reinicia rápidamente en el mismo gen, lo que sugiere un modelo de transferencia directa desde la terminación a los sitios promotores.

Área de la Ciencia:

Biología Molecular Biología Molecular
La bioquímica es la bioquímica.
Genética La genética.

Sus antecedentes:

La ARN polimerasa III (pol III) es crucial para la transcripción de los ARN pequeños.
Comprender los mecanismos detrás de la alta eficiencia de transcripción in vitro de pol III es clave.

Objetivo del estudio:

Esclarecer el mecanismo principal que impulsa la alta eficiencia de transcripción in vitro de la ARN polimerasa III de la levadura.
Investigar la cinética y los requisitos para el reciclaje y la reiniciación de la ARN polimerasa III.

Principales métodos:

Análisis cinético de la transcripción de la ARN polimerasa III.
Plantilla de ensayos de la competencia.
Pruebas de resistencia a la heparina para evaluar la liberación de la polimerasa.

Principales resultados:

El reciclaje de la ARN polimerasa III en complejos de transcripción preensamblados es significativamente más rápido que el ciclo de transcripción inicial.
El reciclaje eficiente requiere la terminación en la señal natural y es favorecido por altas concentraciones de UTP; la transcripción de escorrentía dificulta el reciclaje.
La reiniciación exhibe una mayor resistencia a la heparina, lo que indica que la polimerasa puede no liberarse completamente después de la terminación.
Los ensayos de competencia de la plantilla demuestran el compromiso de la ARN polimerasa III para reiniciar en el mismo gen.

Conclusiones:

La alta eficiencia in vitro de la ARN polimerasa III de levadura se atribuye principalmente al rápido reciclaje de la polimerasa.
Los hallazgos apoyan un modelo que propone la transferencia directa de la ARN polimerasa desde la terminación a los sitios promotores.

Más Videos Relacionados

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker

Published on: January 3, 2019

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events

Published on: May 13, 2019

Videos de Conceptos Relacionados

Bacterial RNA Polymerase

Bacterial RNA Polymerase

Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...

Eukaryotic RNA Polymerases

Eukaryotic RNA Polymerases

RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...

RNA Polymerase II Accessory Proteins

RNA 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...

Transcription Initiation

Transcription Initiation

Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...

Bacterial RNA Polymerase

Bacterial RNA Polymerase

Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...

Eukaryotic RNA Polymerases

Eukaryotic RNA Polymerases

RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...