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La escisión múltiple de transcripción precede a la liberación de la polimerasa en la terminación por la ARN
1Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom.
Cell
|June 8, 2001
Resumen
La terminación de la transcripción de la ARN polimerasa II (pol II) involucra dos eventos distintos: la escisión de preterminación (PTC) mediada por secuencias aguas abajo y la desconexión de la polimerasa que requiere tanto PTC como un sitio poli (A).
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Expresión génica de la expresión génica.
- La bioquímica es la bioquímica.
Sus antecedentes:
- Se sabe que las señales de poliadenilación (poli A) son esenciales para la terminación de la transcripción de la ARN polimerasa II (pol II).
- Los mecanismos precisos que rigen la terminación de la transcripción pol II siguen siendo en gran parte sin aclarar.
Objetivo del estudio:
- Para investigar los eventos secuenciales involucrados en la terminación de la transcripción de la ARN polimerasa II.
- Para aclarar los roles de las secuencias aguas abajo y los sitios poli (A) en el proceso de terminación.
Principales métodos:
- Análisis de transcripciones nacientes de los genes beta y epsilon-globina humanos.
- Identificación y caracterización de los eventos de escisión de preterminación (PTC).
Principales resultados:
- La terminación de la transcripción de Pol II comprende dos eventos distintos y separados temporalmente.
- El clivado de predeterminación (PTC) es facilitado por trayectorias de secuencia aguas abajo del sitio poli (A), causando un clivado de transcripción heterogéneo.
- La desconexión de la polimerasa de la plantilla de ADN requiere una transcripción previa tanto de una secuencia PTC como de un sitio poli (A) funcional.
Conclusiones:
- La terminación de la transcripción por la ARN polimerasa II es un proceso de varios pasos.
- Los elementos de la secuencia aguas abajo del sitio poli (A) juegan un papel crítico en el inicio de la terminación a través de la escisión de preterminación.
- La terminación eficiente requiere la acción coordinada de ambas señales de escisión de preterminación y de poliadenilación.
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