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Auto-emplazamiento inverso del intrón del grupo I de tetrahímena: implicación para la direccionalidad del empalme y
1Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215.
Cell
|April 21, 1989
Resumen
El Tetrahymena rRNA del grupo I es intrónico.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- El Splicing de ARN y ARN.
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los intrones del grupo I son ARN catalíticos de autoespleaje.
- El intrón Tetrahymena rRNA grupo I es un sistema modelo para el estudio de los mecanismos de empalme de ARN.
Objetivo del estudio:
- Para investigar la reversibilidad del empalme de intrones de Tetrahymena rRNA grupo I in vitro.
- Para identificar los factores que influyen en la direccionalidad del empalme de ARN.
- Explorar las implicaciones de la integración intrónica para la transposición.
Principales métodos:
- Ensayos de empalme in vitro utilizando oligoribonucleótidos cortos como sustratos de exones ligados.
- La incubación del ARN exón ligado con un intrón lineal bajo condiciones variables (concentración de ARN, magnesio, temperatura, presencia de guanosina).
- Análisis de los requisitos de la secuencia de exones y el papel de las estructuras secundarias en el empalme.
Principales resultados:
- El empalme de intrones de Tetrahymena rRNA grupo I es completamente reversible in vitro.
- La reversión es favorecida por la alta concentración de ARN, el magnesio, la temperatura y la ausencia de guanosina.
- Las secuencias de exones de 5' emparejadas con la secuencia guía interna del intrón son esenciales; las secuencias de exones de 3' no lo son.
- La integración intrónica en sustratos estructurados se reduce significativamente en comparación con los no estructurados.
- El intrón Tetrahymena puede integrarse en una transcripción de beta-globina.
Conclusiones:
- Las estructuras secundarias de ARN en sustratos de exones pueden impulsar el empalme en la dirección hacia adelante.
- La reversibilidad del empalme tiene implicaciones para la comprensión de la movilidad intrónica y los mecanismos de transposición.
- La transposición de intrones del grupo I puede implicar la integración en diversos objetivos de ARN.
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