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Requisito de RSF y FACT para la transcripción de las plantillas de cromatina in vitro
G LeRoy1, G Orphanides, W S Lane
1Howard Hughes Medical Institute, Division of Nucleic Acid Enzymology, Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
Science (New York, N.Y.)
|December 4, 1998
Resumen
Los investigadores identificaron un nuevo factor, el factor de remodelación y espaciado (RSF, por sus siglas en inglés), crucial para la transcripción génica del ADN empaquetado en cromatina. RSF, junto con FACT, permite la iniciación y elongación de la transcripción en estas plantillas complejas.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Regulación genética Reglamento genético.
- Estructura de la cromatina La estructura de la cromatina
Sus antecedentes:
- La iniciación de la transcripción en el ADN desnudo requiere ARN polimerasa II y factores de transcripción generales.
- El ADN empaquetado en cromatina presenta una barrera significativa para el inicio de la transcripción.
- Los conjuntos de factores de transcripción existentes son insuficientes para la transcripción con plantilla de cromatina.
Objetivo del estudio:
- Para identificar los factores que facilitan la iniciación de la transcripción en las plantillas de cromatina.
- Definir los requisitos mínimos de factores para la transcripción dependiente del activador en la cromatina.
- Caracterizar las actividades de un nuevo factor de transcripción de la cromatina.
Principales métodos:
- Purificación de un factor proteico a partir de extractos celulares.
- Ensayos de transcripción in vitro utilizando plantillas de cromatina.
- Prueba para determinar las actividades de remodelación y espaciado de nucleosomas.
- Análisis funcional del factor purificado en la iniciación y elongación de la transcripción.
Principales resultados:
- Se purificó un nuevo factor, el factor de remodelación y espaciado (RSF, por sus siglas en inglés).
- RSF exhibe actividades de remodelación y espaciado de nucleosomas dependientes del trifosfato de adenosina.
- RSF facilita la iniciación de la transcripción dependiente del activador en las plantillas de cromatina.
- El complejo facilita la transcripción de cromatina (FACT) se requiere para el alargamiento de transcripción por polimerasas iniciadas con RSF.
Conclusiones:
- El estudio define los requisitos mínimos de factores para la transcripción en plantillas de cromatina.
- La RSF es un componente clave para superar la represión de la transcripción basada en la cromatina.
- La acción coordinada de RSF y FACT es esencial para una transcripción eficiente de la cromatina.
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