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La RNA helicasa Mtr4p modula la poliadenilación en el complejo TRAMP

Huijue Jia¹, Xuying Wang, Fei Liu

¹Center for RNA Molecular Biology & Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.

|June 14, 2011

Resumen

El complejo TRAMP, crucial para el procesamiento y la descomposición del ARN, limita la adición de poli (A) cola a 3-4 adenosinas. La RNA helicasa Mtr4p controla esta restricción de longitud mediante la detección de los números de adenosina y el ajuste de la actividad enzimática.

Área de la Ciencia:

Biología Molecular Biología Molecular
ARN Biología Biología ARN
La bioquímica es la bioquímica.

Sus antecedentes:

El complejo TRAMP (Trf4p, Air2p, Mtr4p) es esencial para el procesamiento, la vigilancia y la degradación del ARN nuclear.
TRAMP poliadenila ARN dirigidos a la descomposición por el exosoma nuclear, pero su mecanismo difiere de la poliadenilación convencional.

Objetivo del estudio:

Para dilucidar el mecanismo por el cual TRAMP poliadenila el ARN.
Para entender cómo la actividad de poliadenilación de TRAMP difiere de las polimerasas convencionales poli (A).
Para identificar el papel de la RNA helicasa Mtr4p en la poliadenilación mediada por TRAMP.

Principales métodos:

Reconstitución del complejo TRAMP de Saccharomyces cerevisiae en el laboratorio.
Análisis bioquímicos para medir la actividad de poliadenilación y la cinética de las enzimas.
Análisis de la interacción de la ARN helicasa Mtr4p con TRAMP y su efecto sobre la longitud de la cola de poli (A).

Principales resultados:

El TRAMP reconstituido suprime intrínsecamente la adición de poli (A) más allá de 3-4 adenosinas.
La RNA helicasa Mtr4p es el regulador clave de esta restricción de la longitud de la cola.
Mtr4p detecta el número de adenosinas 3'-terminales y modula las afinidades de ATP y las constantes de velocidad para la adenilación y la disociación de TRAMP.

Conclusiones:

Mtr4p actúa como un regulador crítico de la actividad de poliadenilación de TRAMP.
Las helicasas de ARN pueden controlar intrincadamente la actividad enzimática en respuesta a las características del ARN.
Este estudio revela un nuevo mecanismo para la regulación precisa de la poliadenilación por el complejo TRAMP.

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