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A Method to Study de novo Formation of Chromatin Domains
Published on: August 23, 2019
La deposición de la histona H3.3 dependiente de Hira facilita el reclutamiento de PRC2 en los loci de desarrollo en
Laura A Banaszynski1, Duancheng Wen2, Scott Dewell3
1Laboratory of Chromatin Biology & Epigenetics, The Rockefeller University, New York, New York, 10065 USA.
Cell
|October 1, 2013
Resumen
La variante de histona H3.3 es esencial para que el Complejo Represivo Polycomb 2 (PRC2) establezca marcas de silenciamiento genético (H3K27me3) en células madre embrionarias de ratón (CEM). El agotamiento de H3.3 reduce la unión de PRC2 y la interacción de la chaperona Hira, lo que afecta la diferenciación.
Área de la Ciencia:
- La epigenética y la regulación génica.
- Biología de la cromatina Biología de la cromatina
- Biología del desarrollo Biología del desarrollo.
Sus antecedentes:
- El complejo represivo de policombos 2 (PRC2) es crucial para regular la expresión génica a través de la trimetilación de la histona H3 lisina 27 (H3K27me3).
- En Drosophila, los sitios de unión del policombo son dinámicos y enriquecidos con la variante de histona H3.3.3.
- El papel de H3.3 en el silenciamiento genético mediado por PRC2 en las células madre embrionarias de mamíferos (CEM) sigue siendo incompletamente entendido.
Objetivo del estudio:
- Investigar el papel de la variante de histona H3.3 en el establecimiento de marcas H3K27me3 por PRC2 en promotores de genes del desarrollo en ECS de ratones.
- Para aclarar la relación funcional entre H3.3, PRC2, y la histona chaperona Hira en el mantenimiento de los estados de cromatina cruciales para la diferenciación.
Principales métodos:
- El agotamiento de H3.3 en el ratón ESCs.
- Medición de la rotación de los nucleosomas mediante deposición de histonas sintetizadas de novo.
- Evaluación de la ocupación de PRC2 e interacción con Hira en promotores de genes objetivo.
- Análisis de la localización de la cromatina Hira.
Principales resultados:
- El agotamiento de H3.3 condujo a una reducción del establecimiento de H3K27me3 en promotores de genes de desarrollo.
- Se observó una reducción de la rotación de nucleosomas y la ocupación de PRC2 tras el agotamiento de H3.3.
- H3.3 se requiere para la interacción entre PRC2 y la histona chaperona Hira.
- La localización de Hira en la cromatina es dependiente de H3.3.3.
Conclusiones:
- H3.3 es esencial para el establecimiento adecuado de H3K27me3 por PRC2 en ECS de ratón.
- H3.3 facilita el reclutamiento y la función de PRC2 al interactuar con el chaperón de la histona Hira.
- Estos hallazgos resaltan el papel crítico de H3.3 en el mantenimiento de un paisaje de cromatina necesario para la regulación génica durante la diferenciación, independiente de un estado de cromatina "activo".
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