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Est1p como un activador regulado por el ciclo celular de la telomerasa ligada a los telómeros
Andrew K P Taggart1, Shu-Chun Teng, Virginia A Zakian
1Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Science (New York, N.Y.)
|August 10, 2002
Resumen
Los componentes de la telomerasa Est1p y Est2p se asocian con los telómeros en Saccharomyces cerevisiae. Est2p se une a los telómeros temprano, mientras que Est1p se une tarde, lo que sugiere un modelo para la activación de la telomerasa.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
- Genética La genética.
Sus antecedentes:
- La telomerasa, compuesta por Est2p, ARN TLC1, Est1p y Est3p, es crucial para el mantenimiento de los telómeros en Saccharomyces cerevisiae.
- La actividad de la telomerasa está regulada y se cree que ocurre al final de la fase S, dependiendo del reclutamiento por la proteína telomérica de unión al ADN Cdc13p.
Objetivo del estudio:
- Para investigar la asociación temporal de los componentes de la telomerasa (Est1p, Est2p, Cdc13p) con los telómeros durante el ciclo celular.
- Para aclarar el papel de Cdc13p en el reclutamiento y la activación de los componentes de la telomerasa.
Principales métodos:
- Análisis de la asociación telomérica de Est1p, Est2p y Cdc13p durante diferentes fases del ciclo celular.
- Examen de la asociación de los componentes de la telomerasa en cepas de levadura de tipo silvestre y cdc13-2 mutantes.
Principales resultados:
- Est1p, Est2p y Cdc13p están todas asociadas a los telómeros durante la fase S tardía.
- Est2p, pero no Est1p, se une a los telómeros antes de la fase S tardía.
- La asociación telomérica de Est1p y Est2p persiste en el mutante cdc13-2, lo que desafía el modelo de defecto de reclutamiento propuesto.
Conclusiones:
- Se propone un modelo donde Est1p se une a los telómeros al final de la fase S e interactúa con Cdc13p.
- Esta interacción potencialmente convierte Est2p inactivo, ligado a los telómeros, en un complejo telomerasa activo.
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