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El gen 118 de VSG se transcribe a partir de un promotor tipo poli I cotranspuesto
Cell
|August 14, 1987
Resumen
La expresión génica de la glicoproteína de superficie celular (VSG) de variante diferencial en T. brucei está controlada por reorganizaciones del ADN que activan promotores de ARN polimerasa tipo I (pol I). Este mecanismo de control posicional regula la transcripción del gen VSG y la actividad del sitio de expresión.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Parasitología Parasitología.
- Genética La genética.
Sus antecedentes:
- Trypanosoma brucei evita el sistema inmunológico del huésped cambiando su variante de capa de glicoproteína de superficie celular (VSG).
- La regulación de la expresión génica de VSG es crucial para la supervivencia del parásito y requiere la comprensión de sus complejos mecanismos genéticos y de transcripción.
Objetivo del estudio:
- Investigar los mecanismos que controlan la expresión génica VSG diferencial en T. brucei.
- Para aclarar el papel de los reordenamientos del ADN y la actividad del promotor en la regulación de la transcripción génica VSG.
Principales métodos:
- Análisis de la transposición del gen VSG y la regulación del sitio de expresión.
- Estudio de la actividad promotora de la ARN polimerasa tipo I (pol I) y la ARN polimerasa II (pol II).
- Investigación de la organización génica y la regulación transcripcional dentro de los sitios de expresión.
Principales resultados:
- La transposición duplicativa intercromosómica del gen 118 de VSG activa un promotor de pol I cotranspuesto, lo que lleva a la transcripción del gen VSG.
- La transcripción del gen VSG está regulada por reorganizaciones del ADN que afectan el control de la expresión génica posicional.
- Un mini-exón, transcrito por pol II, se añade en trans al pre-ARNm derivado de pol I.
- El sitio de expresión contiene al menos dos genes regulados de manera independiente, incluido ESAG1 ubicado aguas arriba de VSG 118.
Conclusiones:
- Los reordenamientos del ADN juegan un papel importante en la regulación de la expresión génica VSG a través del control posicional de la activación del promotor.
- La arquitectura del sitio de expresión permite la regulación independiente de múltiples genes, lo que contribuye a la variación antigénica del parásito.
- La localización nucleolar puede ser importante para la regulación de la transcripción del gen VSG y el sitio de expresión.
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