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Analysis of Termination of Transcription Using BrUTP-strand-specific Transcription Run-on (TRO) Approach
Published on: March 12, 2017
Mecanismo de la antiterminación de la transcripción en las mitocondrias humanas
Hauke S Hillen1, Andrey V Parshin2, Karen Agaronyan2
1Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Cell
|October 17, 2017
Resumen
El factor de transcripción TEFM previene la replicación del ADN mitocondrial al suprimir la terminación y la síntesis de primeras de ARN. Este estudio revela que el TEFM
Área de la Ciencia:
- Biología mitocondrial
- Genética molecular
- Biología estructural
Sus antecedentes:
- La replicación del ADN mitocondrial (mtDNA) es iniciada por los primers de ARN generados durante la terminación de la transcripción.
- La terminación de la transcripción ocurre en las regiones G-cuadruplex cerca del origen del ADNmt.
- El TEFM (factor de transcripción mitocondrial) es un regulador clave que suprime este proceso.
Objetivo del estudio:
- Determinar la estructura del complejo anti-terminación formado por el TEFM y la transcripción de la ARN polimerasa mitocondrial (mtRNAP).
- Para aclarar los mecanismos moleculares por los cuales TEFM regula el cambio entre la transcripción y la replicación de ADNmt.
Principales métodos:
- Determinación del complejo estructural de TEFM unido al mtRNAP transcriptor mediante microscopía criolectrónica o cristalografía de rayos X.
- Ensayos bioquímicos para evaluar el efecto de la TEFM en la procesividad y terminación de la transcripción.
Principales resultados:
- La estructura revela el núcleo de la pseudonucleasa dimérica de TEFM que interactúa con el mtRNAP y los componentes de ácido nucleico del complejo de alargamiento.
- El TEFM forma una "clampa deslizante" aguas abajo en el ADN, mejorando la procesividad del complejo de alargamiento.
- TEFM se une cerca del canal de salida de ARN, impidiendo la formación de G-cuadruplex y la síntesis de primeras de replicación.
Conclusiones:
- El TEFM actúa como un regulador crucial, previniendo el inicio prematuro de la replicación del ADNmt.
- La relación estructura-función de TEFM proporciona información sobre su especificidad objetivo y su papel regulador en el equilibrio de la transcripción y la replicación del ADNmt.
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