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El dominio C-terminal de la ARN polimerasa II se modifica mediante una metilación específica del sitio
Robert J Sims1, Luis Alejandro Rojas1, David B Beck1
1Howard Hughes Medical Institute (HHMI), Department of Biochemistry, New York University School of Medicine, 522 First Avenue, Smilow 211, New York, NY 10016, USA.
Science (New York, N.Y.)
|April 2, 2011
Resumen
La metilación de la CTD por la ARN polimerasa II (RNAPII) por CARM1 en R1810 precede al inicio de la transcripción. Esta metilación es crucial para la expresión de ARN pequeños específicos, impactando la regulación génica.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Expresión génica de la expresión génica.
- Modificaciones después de la traducción.
Sus antecedentes:
- El dominio carboxiterminal (CTD) de la ARN polimerasa II (RNAPII) está ampliamente modificado después de la traducción.
- Estas modificaciones son críticas para la regulación de la iniciación y elongación de la transcripción.
Objetivo del estudio:
- Para investigar el papel de la metilación de la arginina en la modificación de RNAPII CTD.
- Para identificar la enzima específica responsable de la metilación de CTD y sus consecuencias funcionales.
Principales métodos:
- Ensayos enzimáticos in vitro para determinar la actividad de CARM1 en el RNAPII CTD.
- Mutagénesis dirigida al sitio de R1810 en RNAPII.
- Análisis de la expresión de ARN pequeño en células/fibroblastos de tipo salvaje y mutantes.
Principales resultados:
- La arginina metiltransferasa 1 (CARM1) asociada con el coactivador metila el ARNPCII CTD en la arginina 1810 (R1810).
- La metilación ocurre en el RNAPII hiperfosforilado in vivo, pero es inhibida por la fosforilación de Ser2/Ser5 in vitro, lo que sugiere un tiempo de preiniciación.
- La mutación R1810 o la deficiencia de CARM1 conduce a la expresión errónea de pequeños ARN nucleares y pequeños ARN nucleolares.
Conclusiones:
- La metilación de CTD por CARM1 en R1810 es una nueva modificación post-traduccional del RNAPII.
- Este evento de metilación es esencial para la expresión adecuada de determinados ARN pequeños.
- La metilación de CTD puede desempeñar un papel en el reclutamiento de maquinaria transcripcional específica para diferentes tipos de genes.
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