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Las secuencias proximales de promotores modulan el alargamiento de la ARN polimerasa II mediante un nuevo mecanismo
1Institute of Molecular Biology and Department of Chemistry, University of Oregon, Eugene 97403, USA.
Cell
|November 15, 1996
Resumen
Los principales sitios de detención tardía del adenovirus impiden la transcripción. La hibridación de ARN o ADN con la transcripción naciente evita este bloqueo, permitiendo que la ARN polimerasa II continúe el alargamiento.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Regulación genética Reglamento genético.
- Maquinaria de transcripción de las transcripciones.
Sus antecedentes:
- La ARN polimerasa II de mamíferos puede detenerse durante la transcripción en secuencias específicas de ADN, conocidas como sitios de arresto.
- El promotor tardío mayor del adenovirus contiene un sitio de arresto que afecta la terminación y el alargamiento de la transcripción.
- Comprender los mecanismos de detención de la transcripción es crucial para regular la expresión génica.
Objetivo del estudio:
- Para investigar los mecanismos moleculares subyacentes a la detención de la transcripción en el sitio de detención tardía mayor del adenovirus.
- Para identificar las secuencias específicas y las estructuras de ARN involucradas en la prevención o promoción de la detención de la transcripción.
- Explorar estrategias para superar la detención de la transcripción para garantizar una expresión génica eficiente.
Principales métodos:
- Ensayos de transcripción in vitro que utilizan la ARN polimerasa II de mamíferos.
- Localización de secuencias anti-arrest utilizando análisis de eliminación y construcciones de promotor.
- Evaluación de la hibridación ARN-ARN y ARN-ADN utilizando oligonucleótidos antisense.
- Análisis del movimiento de transcripción naciente dentro de la polimerasa durante la detención.
Principales resultados:
- El sitio de detención tardía mayor del adenovirus bloquea el alargamiento de la transcripción in vitro, pero no para el promotor de beta-globina del ratón.
- Las secuencias en el extremo 5' de la transcripción de la beta-globina son responsables del antiarrest.
- La actividad anti-arrest requiere un emparejamiento de bases entre la transcripción naciente y las secuencias aguas arriba.
- Los oligonucleótidos de ARN o ADN antisense que se hibridan aguas arriba del sitio de detención previenen el estancamiento de la polimerasa.
Conclusiones:
- La detención de la transcripción implica la retracción de la transcripción naciente en la ARN polimerasa.
- La hibridación de la transcripción naciente a las secuencias aguas arriba evita esta retracción.
- Este mecanismo permite a la ARN polimerasa II eludir los sitios de detención y continuar la transcripción.
- Dirigirse a la hibridación de transcripción ofrece una estrategia potencial para modular la eficiencia de la transcripción.
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