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RAG2 PHD parejas de dedos histona H3 lisina 4 trimetilación con V(D) J recombinación
Adam G W Matthews1, Alex J Kuo, Santiago Ramón-Maiques
1Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Nature
|November 23, 2007
Resumen
La proteína RAG2 reconoce un marcador histónico específico (H3K4me3) crucial para la recombinación V(D) J, esencial para el desarrollo del sistema inmunológico. La interrupción de este reconocimiento causa inmunodeficiencia, vinculando las modificaciones de la histona a la enfermedad humana hereditaria.
Área de la Ciencia:
- La epigenética es la epigenética.
- Biología Molecular Biología Molecular
- Inmunología Inmunología.
Sus antecedentes:
- Los procesos nucleares como la recombinación del ADN están regulados por la estructura de la cromatina.
- Las modificaciones de la histona son reguladores conocidos de la transcripción, pero su papel en la recombinación del ADN no está claro.
Objetivo del estudio:
- Para investigar el papel de las modificaciones histónicas en la recombinación del ADN de mamíferos.
- Para determinar si RAG2, un componente clave de la recombinasa V(D) J, interactúa con las modificaciones de la histona.
Principales métodos:
- Cristalografía de rayos X para determinar la estructura del dedo RAG2 PHD unido a H3K4me3.3.
- Estudios in vivo para evaluar el impacto de las mutaciones que afectan el reconocimiento de H3K4me3 en la recombinación V(D) J.
- Análisis de los datos de los pacientes para las mutaciones en los residuos clave.
Principales resultados:
- RAG2 contiene un dedo PHD que reconoce específicamente la histona H3 trimetilizada en lisina 4 (H3K4me3).
- La estructura cristalina reveló la base molecular de este reconocimiento.
- Las mutaciones que afectan el reconocimiento de H3K4me3 reducen severamente la recombinación de V(D) J in vivo.
- Los niveles reducidos de H3K4me3 también disminuyen la recombinación V(D) J.
- Una mutación crítica (W453) se encuentra en pacientes con síndromes de inmunodeficiencia.
Conclusiones:
- La metilación de la histona juega un papel novedoso en la recombinación del ADN de los mamíferos.
- La interrupción del reconocimiento de la modificación de histonas por RAG2 puede conducir a enfermedades de inmunodeficiencia hereditaria.
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