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Dinámica de la cromatina durante la reprogramación epigenética en la línea germinal del ratón
Petra Hajkova1, Katia Ancelin1, Tanja Waldmann2
1Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
Nature
|March 21, 2008
Resumen
Las células germinales primordiales de ratón (PGC) se someten a la desmetilación del ADN y al borrado de la huella. Este estudio revela cambios de cromatina en dos pasos, incluido el reemplazo de histonas, vinculados a la desmetilación del ADN durante la reprogramación de PGC.
Área de la Ciencia:
- Biología del desarrollo Biología del desarrollo.
- La epigenética es la epigenética.
- Biología celular Biología celular.
Sus antecedentes:
- El desarrollo del linaje de células germinales implica la generación de totipotencia.
- La desmetilación del ADN y el borrado de la huella parental son eventos críticos en las células germinales primordiales de ratón (PGC) alrededor del día embrionario 11.5.5.
- Los mecanismos subyacentes a la reprogramación de PGC siguen siendo en gran medida desconocidos.
Objetivo del estudio:
- Para investigar los cambios de cromatina asociados con la desmetilación del ADN y el borrado de huellas en PGCs de ratón.
- Para comprender los mecanismos moleculares que impulsan la reprogramación de la PGC.
Principales métodos:
- Análisis de las modificaciones de la cromatina y las variantes de histona en GCP en diferentes etapas de desarrollo (E8.5 y en las gónadas).
- Examen de la acumulación de la histona acompañante (HIRA y NAP-1).
- Correlación de los cambios en la cromatina con la desmetilación del ADN en todo el genoma.
Principales resultados:
- La reprogramación de la cromatina PGC ocurre en dos pasos distintos, comenzando con una firma similar a la pluripotencia en E8.5.5.
- Los principales cambios en la arquitectura nuclear, el borrado de la modificación de la histona y el intercambio de variantes de histona ocurren a medida que los PGC ingresan a las gónadas.
- Las chaperonas de histona HIRA y NAP-1 se acumulan en los PGC que se someten a reprogramación, lo que sugiere un papel en el reemplazo de histona.
- Los cambios en la cromatina están estrechamente relacionados con la desmetilación del ADN en todo el genoma.
Conclusiones:
- Es probable que el reemplazo de histonas sea crítico para las reorganizaciones de cromatina observadas durante la reprogramación de PGC.
- El tiempo sugiere que el reemplazo de histonas puede ser una respuesta a la desmetilación del ADN, potencialmente a través de un mecanismo basado en la reparación del ADN, en lugar de un requisito previo.
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