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Biochemical Assays for Analyzing Activities of ATP-dependent Chromatin Remodeling Enzymes
Published on: October 25, 2014
La reparación de la recombinación dentro de la heterocromatina requiere una remodelación de la cromatina dependiente
Manisha Sinha1, Shinya Watanabe, Aaron Johnson
1University of Massachusetts Medical School, Worcester, MA 01605, USA.
Cell
|September 22, 2009
Resumen
Las proteínas sir en la heterocromatina de levadura suprimen la recombinación homóloga. Los remodeladores de cromatina como SWI / SNF pueden superar esta supresión, facilitando los procesos de reparación del ADN.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética La genética.
- Biología de la cromatina Biología de la cromatina
Sus antecedentes:
- La heterocromatina es crucial para mantener la integridad del cromosoma al inhibir la recombinación homóloga.
- Sir2p, Sir3p y Sir4p son componentes estructurales clave de la heterocromatina en Saccharomyces cerevisiae, ubicados en los telómeros y los loci del tipo de apareamiento silencioso.
Objetivo del estudio:
- Investigar cómo las proteínas Sir dentro de los minicromosomas regulan las primeras etapas de la reparación recombinante in vitro.
- Determinar el papel de la remodelación de la cromatina en la superación de la supresión mediada por la heterocromatina de la reparación del ADN.
Principales métodos:
- Ensayos bioquímicos in vitro utilizando sustratos nucleosómicos.
- Investigando los efectos de Sir2p, Sir3p y Sir4p en la formación articular catalizada por yRad51p.
- Evaluación del papel de la enzima remodeladora de la cromatina SWI / SNF en la facilitación de los intermediarios de reparación.
Principales resultados:
- La adición de Sir3p a sustratos nucleosómicos reprimió la formación articular catalizada por yRad51p, con mejora por Sir2p/Sir4p.
- La represión mediada por sir dependía de los residuos de histona esenciales para el silenciamiento in vivo.
- La enzima SWI / SNF desalojó a Sir3p, promoviendo la invasión de cadenas dependientes de Rad54p, un paso clave en la recombinación homóloga.
Conclusiones:
- La heterocromatina impone restricciones a las vías de reparación recombinante.
- Las enzimas de remodelación de la cromatina dependientes de ATP como SWI / SNF son esenciales para superar estas restricciones y facilitar la reparación del ADN dentro de la heterocromatina.
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