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Activación del factor de transcripción IIIC por la proteína E1A del adenovirus por la activación del factor de
W K Hoeffler1, R Kovelman, R G Roeder
1Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021.
Cell
|June 17, 1988
Resumen
El adenovirus E1A activa la transcripción de la ARN polimerasa III mediante la alteración del factor de transcripción IIIC (TFIIIC). La fosforilación de TFIIIC crea una forma más activa, mejorando la expresión génica durante la infección viral.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Virología Virología.
- Reglamento genético Reglamento genético.
Sus antecedentes:
- Se sabe que la proteína E1A del adenovirus estimula la transcripción de los genes de la ARN polimerasa III.
- Investigaciones anteriores habían localizado el factor responsable en el factor de transcripción IIIC (TFIIIC).
Objetivo del estudio:
- Investigar las formas específicas de TFIIIC implicadas en la transcripción mediada por el adenovirus E1A.
- Para aclarar el mecanismo por el cual se regula la actividad de TFIIIC.
Principales métodos:
- Separación cromatográfica del TFIIIC en formas distintas.
- Ensayos de cambio de gel para analizar complejos gen-proteína VA.
- Ensayos de transcripción in vitro para medir la actividad transcripcional.
- Tratamiento con fosfatasa para evaluar la interconversión de los formularios TFIIIC.
Principales resultados:
- Se identificaron dos formas separables de TFIIIC, que difieren en su capacidad para formar complejos gen-proteína VA.
- Una forma más activa de TFIIIC se asoció con una unión más rápida del promotor y un aumento de la resistencia a la sal.
- La expresión de E1A o el aumento de la concentración sérica condujo a niveles más altos de la forma activa TFIIIC.
- La concentración total de TFIIIC se mantuvo constante durante la infección viral.
Conclusiones:
- La activación transcripcional de los genes de la ARN polimerasa III por el adenovirus E1A está mediada por distintas formas de TFIIIC.
- La fosforilación de TFIIIC es un mecanismo regulador clave que controla su actividad.
- Este evento de fosforilación mejora el papel de TFIIIC en la expresión génica viral.
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