Video Experimental Relacionado
Updated: Jul 10, 2026
10:59
Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Bases moleculares de la actividad de la ARN polimerasa II dependiente del ARN
Elisabeth Lehmann1, Florian Brueckner, Patrick Cramer
1Gene Center Munich and Center for integrated Protein Science (CiPSM), Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
Nature
|November 16, 2007
Resumen
La ARN polimerasa II (Pol II) exhibe actividad intrínseca de ARN dependiente de ARN polimerasa (RdRP), actuando como una replicasa antigua. Este descubrimiento sugiere que Pol II evolucionó a partir de enzimas de replicación de ARN, cerrando una brecha en la comprensión de la evolución molecular.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- Biología evolutiva Biología evolutiva.
Sus antecedentes:
- La ARN polimerasa II (Pol II) es principalmente conocida por la síntesis de ARN dependiente del ADN durante la transcripción.
- La evidencia sugiere que Pol II también puede poseer actividad de ARN dependiente de ARN polimerasa (RdRP), implicada en la replicación del ARN viral.
Objetivo del estudio:
- Demostrar y caracterizar la actividad intrínseca de RdRP de la ARN polimerasa II purificada.
- Aclarar las bases estructurales y mecánicas de la función RdRP de Pol II y sus implicaciones evolutivas.
Principales métodos:
- En ensayos in vitro se utilizaron Pol II purificado, plantillas de ARN y trifosfatos nucleósidos.
- Cristalografía de rayos X para determinar la estructura de Pol II con una plantilla de ARN-duplex de producto.
- Investigando el papel del factor de transcripción IIS (TFIIS) en la modulación de la actividad de RdRP.
Principales resultados:
- Pol II exhibe actividad intrínseca de RdRP utilizando una plantilla de ARN, con el sitio activo que se superpone al sitio de transcripción dependiente del ADN.
- La actividad de RdRP es más lenta y menos procesada que la transcripción dependiente del ADN.
- TFIIS facilita la escisión y la extensión en una plantilla de antígeno de HDV, lo que sugiere un papel en la replicación del ARN.
Conclusiones:
- Pol II posee actividad RdRP inherente, funcionando de manera similar a las antiguas replicas de ARN.
- Este hallazgo proporciona un vínculo molecular que sugiere que Pol II evolucionó a partir de enzimas de replicación del genoma de ARN.
- La actividad RdRP de Pol II ofrece información sobre la evolución de la expresión génica y los mecanismos de replicación del ARN.
Más Videos Relacionados
Videos de Conceptos Relacionados
00:58Eukaryotic 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...
All three eukaryotic RNAPs require specific transcription factors, of which the...
00:58Eukaryotic 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...
All three eukaryotic RNAPs require specific transcription factors, of which the...
01:47Transcription 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...
The promoters and enhancers and their accessory proteins allow tight regulation of...
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...
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...
00:43Bacterial 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...
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...