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Analysis of RNA Processing Reactions Using Cell Free Systems: 3' End Cleavage of Pre-mRNA Substrates in vitro
Published on: May 3, 2014
El factor de poliadenilación CPSF-73 es la endonucleasa de procesamiento de extremo 3' del pre-ARNm
Corey R Mandel1, Syuzo Kaneko, Hailong Zhang
1Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
Nature
|November 28, 2006
Resumen
Se ha identificado la proteína del factor 73 de especificidad de escisión y poliadenilación (CPSF-73) como la endonucleasa responsable del procesamiento de los precursores de ARN mensajero (pre-ARNm). Este hallazgo proporciona evidencia directa para el CPSF-73
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
Sus antecedentes:
- El procesamiento del pre-ARNm eucariótico involucra la escisión del 3'-end y la poliadenilación.
- La enzima endonucleasa específica responsable de este paso crucial se mantuvo sin identificar.
- Estudios previos sugirieron CPSF-73 como un candidato potencial, pero carecían de confirmación experimental directa.
Objetivo del estudio:
- Para determinar la estructura cristalina del CPSF-73 humano y del CPSF-100.00 de levadura.
- Para investigar la actividad enzimática y la especificidad del sustrato de CPSF-73.
- Proporcionar evidencia experimental directa para el papel de CPSF-73 en el procesamiento de pre-ARNm.
Principales métodos:
- Se utilizó la cristalografía de rayos X para determinar las estructuras del CPSF-73 humano y del CPSF-100 de levadura.
- Purificación del CPSF-73 recombinante para ensayos enzimáticos in vitro.
- Mutagénesis dirigida al sitio para sondear la función de los iones de zinc del sitio activo.
Principales resultados:
- Las estructuras cristalinas revelaron que CPSF-73 y CPSF-100 poseen dominios de metallo-beta-lactamasa y beta-CASP.
- El sitio activo de CPSF-73, que contiene dos iones de zinc, se encuentra en la interfaz de estos dominios.
- El CPSF-73 purificado demostró actividad de la RNA endonucleasa, que fue abolida por mutaciones que afectan la unión al zinc.
Conclusiones:
- CPSF-73 está directamente confirmado como la endonucleasa responsable del procesamiento pre-mRNA 3'-end.
- Los datos estructurales y bioquímicos aclaran el mecanismo de CPSF-73 en la maduración del ARN.
- Este descubrimiento aclara un paso fundamental en la expresión génica eucariota.
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