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Mecanismo de terminación de la transcripción de la ARN polimerasa III en los eucariotas

Soren Nielsen¹, Yulia Yuzenkova, Nikolay Zenkin

¹Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK.

Science (New York, N.Y.)

|July 2, 2013

Resumen

La terminación de la ARN polimerasa III (Pol III) se basa en la estructura de la transcripción, no sólo en las señales de poli-T. Las estructuras secundarias de ARN guían la liberación de Pol III, lo que sugiere mecanismos de terminación antiguos compartidos con las bacterias.

Área de la Ciencia:

Biología Molecular Biología Molecular
Genética La genética.
La bioquímica es la bioquímica.

Sus antecedentes:

La regulación de la expresión génica es crucial para la función celular.
La ARN polimerasa III (Pol III) transcribe los ARN no codificantes esenciales.
El proceso de terminación para la transcripción de Pol III no se entiende bien.

Objetivo del estudio:

Para dilucidar el mecanismo de terminación de la transcripción por la ARN polimerasa III.
Para identificar los factores que dictan la liberación de los complejos de alargamiento Pol III.
Para explorar la conservación evolutiva de los mecanismos de terminación de la transcripción.

Principales métodos:

Análisis de la transcripción de la ARN polimerasa III en vitro.
Investigación de la estructura de transcripción y su papel en la terminación.
Análisis comparativo de la terminación de la polimerasa de ARN Pol III y bacteriana.

Principales resultados:

Las extensas estructuras secundarias de ARN dentro de las transcripciones de Pol III son clave para la terminación.
La señal de terminación de poli-T induce la inactivación y el retroceso de Pol III.
Las estructuras secundarias de ARN facilitan la liberación de Pol III de la plantilla de ADN.
Los mecanismos de terminación muestran similitudes entre Pol III y la ARN polimerasa bacteriana.

Conclusiones:

La terminación de Pol III es un proceso dependiente de la estructura que implica la liberación mediada por transcripción.
La terminación dependiente de la horquilla puede ser un antiguo mecanismo conservado a través de diversas polimerasas de ARN.
Comprender la terminación del Pol III proporciona información sobre la regulación de la expresión génica y la historia evolutiva.

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