Recombinación V(D) J en timocitos de ratón: rupturas de doble hebra cerca de las señales de reordenamiento del receptor delta de las células T
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Published on: February 3, 2013
D B Roth1, P B Nakajima, J P Menetski
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Cell
|April 3, 1992
Resumen
Este estudio encontró roturas de ADN de doble hebra en sitios específicos en el ADN del timo del ratón, proporcionando evidencia directa de la escisión del ADN durante la recombinación V(D) J. Estos hallazgos apoyan un modelo de ruptura-reunión para este proceso crucial del sistema inmunológico.
Área de la Ciencia:
- Inmunología Inmunología.
- Biología Molecular Biología Molecular
- Genética La genética.
Sus antecedentes:
- La recombinación V(D) J es un proceso crítico para generar diversos receptores de células T (TCR) en el locus delta del receptor de células T murinas.
- Frecuentes eventos de recombinación involucran a los elementos D2 y J1 dentro de este locus.
Objetivo del estudio:
- Para investigar los mecanismos moleculares subyacentes a la recombinación V(D) J en el locus delta del TCR.
- Proporcionar evidencia directa de la escisión del ADN durante la recombinación V(D) J en células de mamíferos.
Principales métodos:
- Análisis del ADN del timo murino para detectar la presencia de rupturas de doble hebra (DSB).
- Detección de especies específicas de ADN, incluidos fragmentos lineales extirpados y productos circulares, asociados con señales de recombinación.
- Análisis comparativo del ADN del timo, el hígado y el bazo para identificar eventos específicos del tejido.
Principales resultados:
- Aproximadamente el 2% del ADN del timo exhibió roturas de doble hebra en las señales de recombinación que flanqueaban el elemento D2.
- Se identificaron fragmentos de ADN lineal cortados (secuencias entre D2 y J1) y productos circulares (unión de señales D2 y J1).
- Se detectaron moléculas rotas con extremos de señal, pero no se encontraron especies con extremos de codificación. Estas rupturas eran específicas del tejido del timo.
Conclusiones:
- La detección de moléculas rotas en el ADN del timo proporciona la primera evidencia directa que vincula la escisión específica del ADN cromosómico con la recombinación V ((D) J en los mamíferos.
- Estos hallazgos apoyan fuertemente un modelo de ruptura-reunión para la recombinación V(D) J.
- La observación específica del tejido de estas rupturas pone de relieve los eventos moleculares únicos que ocurren durante la recombinación V(D) J en el desarrollo de las células inmunes.
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