Video Experimental Relacionado

Updated: Sep 6, 2025

CD Spectroscopy to Study DNA-Protein Interactions

CD Spectroscopy to Study DNA-Protein Interactions

Published on: February 10, 2022

Estructura del heterodímero Dicer-2-R2D2 unido a un pequeño dúplex de ARN

Sonomi Yamaguchi¹, Masahiro Naganuma^2,3, Tomohiro Nishizawa⁴

¹Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.

|June 29, 2022

Resumen

La proteína R2D2 en las moscas ayuda a cargar pequeños ARN interferentes (siRNA) en Argonaute2 (Ago2) mediante el reconocimiento de siRNA

Área de la Ciencia:

Biología molecular
Biología estructural
Interferencia del ARN

Sus antecedentes:

Argonaute2 (Ago2) y el pequeño ARN interferente (siRNA) forman complejos silenciadores inducidos por ARN para reprimir las transcripciones virales en las moscas.
La enzima Dicer-2, con su compañero R2D2, procesa ARN de doble cadena en siRNA para la carga de Ago2.

Objetivo del estudio:

Determinar las estructuras de criomicroscopía de los complejos Dicer-2-R2D2 y Dicer-2-R2D2-siRNA.
Para aclarar el mecanismo por el cual R2D2 regula la actividad de Dicer-2 y facilita la carga de siRNA en Ago2.

Principales métodos:

Se utilizó la criomicroscopia electrónica (Cryo-EM) para obtener estructuras de alta resolución.
Es probable que se hayan empleado ensayos bioquímicos para estudiar las interacciones proteicas y la actividad enzimática.

Principales resultados:

La estructura revela la interacción de R2D2 con Dicer-2, inhibiendo el procesamiento del precursor de microARN.
La estructura captura el estado de selección de hebras durante la carga de siRNA, mostrando el reconocimiento asimétrico de R2D2 del extremo de siRNA más estable.
Esta interacción facilita la carga específica de la orientación del siRNA en Ago2.

Conclusiones:

R2D2 juega un papel crucial para garantizar la orientación correcta de la carga de siRNA en Ago2 mediante la detección de la asimetría termodinámica del siRNA.
Este mecanismo de carga precisa dicta la hebra guía utilizada por Ago2 para silenciar el objetivo, mejorando la especificidad de la interferencia de ARN.

Más Videos Relacionados

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Published on: September 28, 2017

Dual DNA Rulers to Study the Mechanism of Ribosome Translocation with Single-Nucleotide Resolution

Dual DNA Rulers to Study the Mechanism of Ribosome Translocation with Single-Nucleotide Resolution

Published on: July 8, 2019

Videos de Conceptos Relacionados

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...

Experimental RNAi

Experimental RNAi

RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the...

siRNA - Small Interfering RNAs

siRNA - Small Interfering RNAs

Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional level in some cases. siRNAs are important for protecting cells against viral infections and silencing transposable genetic elements.
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the...

Nucleic Acid Structure

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group on the ribose's second carbon and a hydrogen on the deoxyribose's second carbon. The phosphate residue attaches to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′ to 3′ phosphodiester linkage.
DNA Structure
DNA...

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...

Nucleic Acids

Nucleic Acids

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell's genetic blueprint and carry instructions for its functioning.
DNA and RNA
The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is the genetic material in all living organisms, ranging from single-celled bacteria to multicellular mammals. It is in the nucleus of eukaryotes and in the organelles, chloroplasts, and mitochondria. In prokaryotes,...