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La expresión de Xist durante el desarrollo del ratón sugiere un papel en el inicio de la inactivación del cromosoma X
1Section of Comparative Biology, Medical Research Council Clinical Research Centre, Harrow, England.
Cell
|January 29, 1993
Resumen
El gen Xist del ratón inicia la inactivación del cromosoma X, que precede al proceso en sí. Su expresión impresa en el desarrollo temprano sugiere que Xist causa la inactivación paterna de X, con alelos Xce que modulan este efecto.
Área de la Ciencia:
- Genética La genética.
- Biología del desarrollo Biología del desarrollo.
- La epigenética es la epigenética.
Sus antecedentes:
- El gen Xist se encuentra en el centro de inactivación X (Xic) y se expresa desde el cromosoma X inactivo.
- Xist es un gen candidato para controlar la inactivación del cromosoma X (XCI).
Objetivo del estudio:
- Investigar la relación temporal entre la expresión génica Xist y la inactivación del cromosoma X durante el desarrollo del ratón.
- Para determinar si la expresión de Xist es una causa o consecuencia de XCI.
Principales métodos:
- Análisis del tiempo de expresión del gen Xist en morulas y blastocistos de ratón.
- Investigación de la expresión específica del alelo Xist y de los patrones de impresión.
- Examen de la influencia de los alelos Xce (elemento controlador de X) en la expresión de Xist y XCI.
Principales resultados:
- La expresión del xista comienza antes de la inactivación del cromosoma X, lo que sugiere un papel causal.
- La expresión temprana de Xist está impresa, favoreciendo el alelo paterno, lo que puede causar la inactivación del X paterno en el trofectodermo.
- Los alelos Xce fuertes pueden mitigar los efectos de la expresión Xist impresa en el trofectodermo.
- La huella de Xist se pierde antes de la gastrulación, coincidiendo con la inactivación aleatoria de X.
Conclusiones:
- Xist juega un papel directo en el inicio de la inactivación del cromosoma X.
- La expresión de Xist impresa es probablemente la causa de la inactivación de X paterna no aleatoria en el desarrollo temprano.
- Los alelos Xce modulan el proceso de XCI al influir en la expresión Xist impresa.
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