Video Experimental Relacionado
Updated: Jul 11, 2026
13:42
RNA Secondary Structure Prediction Using High-throughput SHAPE
Published on: May 31, 2013
Cambios inducidos por el ARN IRES del virus de la hepatitis C en la conformación de la subunidad ribosómica 40s
C M Spahn1, J S Kieft, R A Grassucci
1Howard Hughes Medical Institute, Health Research Inc. at the, Wadsworth Center, Empire State Plaza, Albany, New York 12201-0509, USA.
Science (New York, N.Y.)
|March 10, 2001
Resumen
El sitio de entrada ribosómica interna (IRES) del virus de la hepatitis C se une a la subunidad ribosómica 40S, alterando su forma. Esta interacción sugiere un mecanismo para cómo IRES posiciona el ARN mensajero para la síntesis de proteínas.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Virología Virología.
- Biología Estructural Biología estructural.
Sus antecedentes:
- La iniciación de la síntesis de proteínas en los eucariotas generalmente implica la unión de la subunidad ribosómica 40S con el ARN mensajero (ARNm) 5' cap.
- Una vía alternativa, el sitio de entrada ribosómica interna (IRES, por sus siglas en inglés), permite la iniciación de la traducción independiente de la capa utilizando elementos de ARN estructurado dentro del ARNm o ARN viral.
- El virus de la hepatitis C (VHC) utiliza un IRES para su traducción, lo que lo convierte en un objetivo clave para comprender mecanismos de iniciación alternativos.
Objetivo del estudio:
- Para aclarar la base estructural de la iniciación de la traducción mediada por el sitio de entrada ribosómica interna (IRES).
- Para visualizar la interacción entre el virus de la hepatitis C (VHC) IRES y la subunidad ribosómica 40S.
Principales métodos:
- Se empleó la microscopía criolectrónica (cryo-EM) para generar un mapa estructural.
- El mapa se obtuvo para el HCV IRES complejado con la subunidad ribosómica 40S.
- La resolución del mapa cryo-EM fue de aproximadamente 20 Å.
Principales resultados:
- Se obtuvo un mapa detallado de microscopía criolectrónica del HCV IRES unido a la subunidad ribosómica 40S.
- Se observó que la unión de IRES induce cambios conformacionales significativos en la subunidad ribosómica 40S.
- Se encontró que la hendidura de unión de ARNm de la subunidad 40S se cerró después de la unión IRES.
Conclusiones:
- Los datos estructurales proporcionan información sobre el mecanismo de iniciación de la traducción independiente del límite por HCV IRES.
- Los cambios conformacionales observados sugieren un papel para IRES en el posicionamiento activo del ARNm dentro del centro de decodificación ribosomal.
- Este hallazgo contribuye a comprender las estrategias de traducción del ARN viral y los posibles objetivos terapéuticos.
Videos de Conceptos Relacionados
01:23RNA 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...
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...
02:28Leaky Scanning
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
02:30siRNA - 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 ATP-dependent...
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 ATP-dependent...
02:15Experimental 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...
01:29Viruses with RNA Genomes
RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
01:25Inhibitors Of Virion Release
Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...