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Origen bacteriano de un intrón de cloroplasto: intrones autoesplicantes del grupo I conservados en las cianobacterias
M Q Xu1, S D Kathe, H Goodrich-Blair
1Department of Biological Sciences, State University of New York, Albany 12222.
Science (New York, N.Y.)
|December 14, 1990
Resumen
Se descubrieron intrones del grupo I en los genes de ARN de transferencia de leucina de las cianobacterias Anabaena. Estos intrones se asemejan a los de los cloroplastos de las plantas, lo que sugiere que los intrones existían antes de que evolucionaran los cloroplastos.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología evolutiva Biología evolutiva.
- Genética La genética.
Sus antecedentes:
- Las cianobacterias son microorganismos fotosintéticos vitales para la fijación del nitrógeno.
- Los genes de ARN de transferencia (ARNt) son esenciales para la síntesis de proteínas.
- Los intrones del grupo I son elementos de ARN autoesplicantes que se encuentran en varios organismos.
Objetivo del estudio:
- Para investigar la presencia y las características de los intrones en los genes de tRNA de Anabaena.
- Para comparar los intrones de Anabaena con los que se encuentran en otros organismos, particularmente los cloroplastos.
- Para inferir el origen evolutivo de los intrones del grupo I en el contexto de la endosimbiosis.
Principales métodos:
- Análisis de secuencia de genes de ARNt de leucina en especies de Anabaena.
- Genómica comparativa para identificar intrones homólogos.
- Análisis filogenético para comprender la evolución intron.
Principales resultados:
- Se identificó un intrón del grupo I de auto-espleaje en el gen de ARNt de leucina de dos especies de Anabaena.
- El intrón identificado comparte una similitud significativa con un intrón en la misma posición en los genes de ARNt de los cloroplastos vegetales.
- Este hallazgo sugiere una estructura intrónica conservada a través de diferentes linajes evolutivos.
Conclusiones:
- La presencia de intrones similares del grupo I en Anabaena y los cloroplastos apoya la teoría endosimbiótica.
- Los intrones del grupo I probablemente fueron anteriores al evento endosimbiótico donde las cianobacterias se convirtieron en cloroplastos.
- Este estudio proporciona información sobre la evolución temprana de los intrones y su papel en la expresión génica en procariotas y eucariotas tempranas.
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