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El complejo de reconocimiento de origen, SIR1, y el requisito de la fase S para el silenciamiento
C A Fox1, A E Ehrenhofer-Murray, S Loo
1Department of Molecular and Cell Biology, Division of Genetics, 401 Barker Hall, University of California, Berkeley, CA 94720, USA.
Science (New York, N.Y.)
|June 6, 1997
Resumen
El silenciamiento de la transcripción en Saccharomyces cerevisiae implica la replicación del ADN. El complejo de reconocimiento de origen (ORC) y el paso de fase S son cruciales para el silenciamiento, con funciones separables del inicio de la replicación.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética La genética.
- Biología celular Biología celular.
Sus antecedentes:
- El silenciamiento de la transcripción en Saccharomyces cerevisiae está relacionado con la replicación del ADN.
- El complejo de reconocimiento de origen (ORC) juega un papel tanto en la iniciación de la replicación del ADN como en el silenciamiento transcripcional.
- El establecimiento de silenciamiento en los loci HML y HMR requiere el paso a través de la fase S.
Objetivo del estudio:
- Para investigar la relación entre la replicación del ADN y el silenciamiento transcripcional en Saccharomyces cerevisiae.
- Determinar las funciones específicas de ORC y fase S en el silenciamiento en las localizaciones HML y HMR.
- Para diferenciar las funciones de ORC en la iniciación de la replicación frente al silenciamiento transcripcional.
Principales métodos:
- Investigando el requisito del paso de fase S para el silenciamiento de HMR en condiciones donde no se requiere ORC.
- Examinando el efecto de la unión de la proteína Sir1 al silenciador HMR-E en el silenciamiento dependiente de ORC.
- Evaluación del papel independiente de Sir1 de ORC en el silenciamiento transcripcional telomérico.
Principales resultados:
- El paso a través de la fase S es necesario para el silenciamiento de HMR, independientemente del papel de ORC en la iniciación de la replicación.
- El requisito de ORC en el silenciador HMR se puede eludir atando Sir1 al silenciador HMR-E.
- ORC tiene un papel distinto e independiente de Sir1 en el silenciamiento transcripcional telomérico.
Conclusiones:
- El papel de ORC en el silenciamiento de la transcripción es separable de su función en la iniciación de la replicación del ADN.
- El paso de fase S es esencial para el silenciamiento, independiente del inicio de la replicación en los silenciadores.
- Estos hallazgos aclaran distintos mecanismos por los cuales los procesos de replicación del ADN influyen en el silenciamiento de genes.
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