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Quick Fluorescent In Situ Hybridization Protocol for Xist RNA Combined with Immunofluorescence of Histone Modification in X-chromosome Inactivation
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El emparejamiento transitorio de cromosomas homólogos marca el inicio de la inactivación X
Na Xu1, Chia-Lun Tsai, Jeannie T Lee
1Howard Hughes Medical Institute, Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School Boston, MA 02114, USA.
Science (New York, N.Y.)
|January 21, 2006
Resumen
La inactivación X de los mamíferos implica el emparejamiento del cromosoma X-X, mediado por Xite y Tsix. Este emparejamiento asegura un silenciamiento mutuamente exclusivo para la compensación de la dosis en las hembras.
Área de la Ciencia:
- Genética La genética.
- La epigenética es la epigenética.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La inactivación X de los mamíferos iguala la dosis del gen del cromosoma X entre las hembras XX y los machos XY.
- La inactivación de X está regulada en cis por Xite, Tsix y Xist, pero los mecanismos de acción trans para el silenciamiento mutuamente exclusivo no están claros.
Objetivo del estudio:
- Investigar el papel de la comunicación intercromosómica en la regulación de la inactividad de X.
- Determinar si Xite y Tsix funcionan en trans para garantizar el silenciamiento mutuamente exclusivo del cromosoma X.
Principales métodos:
- Análisis de las interacciones X-X y X-autosoma utilizando técnicas de captura de la conformación cromosómica.
- Manipulación genética de los loci Xite y Tsix para evaluar su impacto en el emparejamiento y la inactivación.
- Observando los efectos del emparejamiento ectópico del X-autosoma en el emparejamiento X-X endógeno y la iniciación de la inactivación.
Principales resultados:
- El emparejamiento intercromosómico entre los cromosomas X ocurre transitoriamente al inicio de la inactivación de X, específicamente en el centro de inactivación de X.
- La eliminación de Xite y Tsix interrumpe el emparejamiento X-X y el proceso de conteo/elección.
- La inserción autosómica de Xite y Tsix induce el emparejamiento del autosoma X, inhibiendo el emparejamiento endógeno X-X y bloqueando la inactivación de X.
Conclusiones:
- El emparejamiento intercromosómico es un mecanismo clave que media la comunicación entre los cromosomas X durante la inactivación.
- Xite y Tsix funcionan tanto en cis como en trans para regular el emparejamiento X-X, el conteo y la elección mutuamente exclusiva.
- Tsix y Xite probablemente controlan el inicio de la inactivación de X a través de interacciones de emparejamiento X-X.
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