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Inactivación del cromosoma X en embriones de ratón clonados
K Eggan1, H Akutsu, K Hochedlinger
1Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA.
Science (New York, N.Y.)
|November 25, 2000
Resumen
La clonación restablece las marcas epigenéticas en los cromosomas X en embriones de ratón. El estudio muestra que las marcas epigenéticas pueden eliminarse y restablecerse durante la clonación, influyendo en los patrones de inactivación del cromosoma X.
Área de la Ciencia:
- La epigenética es la epigenética.
- Biología del desarrollo Biología del desarrollo.
- Ciencias de la Reproducción Ciencias Reproductivas
Sus antecedentes:
- Existen diferencias epigenéticas entre los dos cromosomas X en las células somáticas femeninas.
- La inactivación del cromosoma X (XCI) es un proceso crucial en las hembras de los mamíferos para la compensación de la dosis.
- Comprender la reprogramación epigenética durante la clonación es vital para la biología del desarrollo.
Objetivo del estudio:
- Para investigar si la clonación restablece las diferencias epigenéticas entre los dos cromosomas X en un núcleo femenino somático.
- Para analizar los patrones de inactivación del cromosoma X en embriones de ratón clonados.
- Para comparar las marcas epigenéticas impuestas durante la gametogénesis frente al XCI somático.
Principales métodos:
- Monitoreo de la inactivación X en embriones de ratón clonados.
- Utilizando células somáticas y células madre embrionarias como donantes nucleares.
- Analizando los patrones de inactivación de X en el embrión propiamente dicho y en el trofectodermo (TE).
Principales resultados:
- Ambos cromosomas X estaban activos durante la escisión de los embriones clonados.
- La inactivación aleatoria de X se produjo en el embrión propiamente dicho.
- Se observó una inactivación de X no aleatoria en el trofectodermo (TE), con el X inactivo del donante preferentemente inactivado.
- Cuando se utilizan células madre embrionarias, se observó una inactivación aleatoria de X tanto en TE como en embrión.
Conclusiones:
- Las marcas epigenéticas en los cromosomas X se pueden eliminar y restablecer durante el proceso de clonación.
- La clonación puede restablecer y volver a imponer marcas epigenéticas en los cromosomas X.
- Las marcas epigenéticas establecidas durante la gametogénesis para XCI impreso en TE son funcionalmente equivalentes a las establecidas durante XCI somático.
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