Video Experimental Relacionado

Updated: Jan 27, 2026

Identification of Footprints of RNA:Protein Complexes via RNA Immunoprecipitation in Tandem Followed by Sequencing RIPiT-Seq

Identification of Footprints of RNA:Protein Complexes via RNA Immunoprecipitation in Tandem Followed by Sequencing RIPiT-Seq

Published on: July 10, 2019

Estructura de un complejo de exosomas de Rrp6-ARN unido a poli(A) ARN

Elizabeth V Wasmuth¹, Kurt Januszyk², Christopher D Lima³

¹1] Structural Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, New York 10065, USA [2] Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA.

|July 22, 2014

Resumen

El complejo de exosomas de ARN, crucial para el procesamiento de ARN, dirige los sustratos a las enzimas Rrp6 o Rrp44. Este estudio revela las bases estructurales de Rrp6.

Área de la Ciencia:

Biología Molecular Biología Molecular
Biología Estructural Biología estructural.
La bioquímica es la bioquímica.

Sus antecedentes:

El exosoma del ARN eucariota es un complejo de múltiples subunidades responsable del procesamiento y la degradación del ARN.
Comprende un complejo de núcleo (Exo9) y exoribonucleasas catalíticas (Rrp6 y Rrp44) con actividades distintas.
El mecanismo por el cual los sustratos de ARN se dirigen a Rrp6, y si utiliza el canal exosómico central, sigue sin estar claro.

Objetivo del estudio:

Para dilucidar el mecanismo estructural del compromiso del sustrato de ARN por la subunidad de la exoribonucleasa Rrp6.
Determinar la vía de unión y procesamiento de ARN que involucra a Rrp6 dentro del complejo de exosomas de ARN.
Investigar el papel de la estructura central del exosoma en la dirección del ARN a diferentes subunidades catalíticas.

Principales métodos:

Cristalografía de rayos X de un complejo de exosomas de ARN de diez subunidades (núcleo Exo9 + Rrp6) unido a ARN poli (A) a una resolución de 3,3 Å.
Ensayos bioquímicos y estudios de soluciones utilizando complejos de exosomas de ARN de levadura y humano.
Análisis estructural del posicionamiento del ARN en relación con el sitio activo de Rrp6 y el núcleo exosómico.

Principales resultados:

Una estructura cristalina reveló el dominio catalítico de Rrp6 situado en la parte superior del anillo Exo9 S1/KH, con el extremo 3' del ARN anclado en el sitio activo de Rrp6.
El ARN unido atraviesa el anillo S1/KH en una orientación distinta de la observada para Rrp44.4.
Los estudios de solución indicaron que la vía de ARN hacia Rrp6 se conserva y depende de la integridad del anillo S1/KH.
In vitro, la selección de la vía de ARN hacia Rrp6 o Rrp44 parece estocástica.

Conclusiones:

La exoribonucleasa Rrp6 utiliza un sitio de unión distinto en el exosoma del ARN, situado por encima del canal central.
El anillo S1/KH del núcleo del exosoma juega un papel crucial en la mediación del acceso del ARN a Rrp6.
Mientras que las vías in vitro son estocásticas, la orientación al sustrato in vivo puede estar influenciada por los cofactores de unión al ARN.

Más Videos Relacionados

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

Isolation and Characterization of RNA-Containing Exosomes

Isolation and Characterization of RNA-Containing Exosomes

Published on: January 9, 2012

Videos de Conceptos Relacionados

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 Structure

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...

RNA Structure

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...

RNA Stability

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...

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...

RNA Interference

RNA Interference

RNA interference (RNAi) is a process in which a small non-coding RNA molecule blocks the post-transcriptional expression of a gene by binding to its messenger RNA (mRNA) and preventing the protein from being translated.
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...