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Aislamiento del gen estructural putativo para la endopeptidasa de división lisina-arginina requerida para el
Cell
|July 1, 1984
Resumen
El gen KEX2 de Saccharomyces cerevisiae codifica una endopeptidasa crucial. Esta enzima es esencial para procesar péptidos secretados como el factor alfa, y su ausencia en los mutantes kex2 conduce a una producción y secreción de péptidos defectuosos.
Área de la Ciencia:
- Biología molecular La biología molecular.
- Genética de la levadura genética de la levadura.
- Procesamiento de proteínas procesamiento de proteínas.
Sus antecedentes:
- Los mutantes de Saccharomyces cerevisiae kex2 exhiben defectos en la producción de péptidos secretados, incluida la toxina asesina y el factor alfa.
- Estos péptidos se derivan de los polipéptidos precursores más grandes que se someten a una escisión proteolítica.
- En los mutantes kex2, el precursor del factor alfa se procesa incorrectamente y se secreta en un estado hiperglucosilado.
Objetivo del estudio:
- Para identificar el gen responsable del defecto de procesamiento proteolítico en los mutantes kex2.
- Para caracterizar la actividad enzimática asociada con el gen KEX2.
- Para aclarar el papel de KEX2 en la maduración y secreción de péptidos de levadura.
Principales métodos:
- Aislamiento del gen KEX2 de tipo silvestre por complementación de fenotipos mutantes de kex2.
- Cruces genéticos para confirmar la cosegregación de mutaciones y fenotipos.
- Ensayos enzimáticos in vitro para detectar la actividad de la endopeptidasa.
- Análisis del procesamiento del factor pre-pro-alfa y la glicosilación in vivo.
Principales resultados:
- Los mutantes de kex2 carecen de una actividad específica de endopeptidasa asociada a la membrana sensible al Zn ++.
- El gen KEX2 clonado restauró la actividad de la endopeptidasa in vitro.
- La expresión del gen KEX2 corrigió los defectos de procesamiento proteolítico y glucosilación del factor pre-pro-alfa in vivo.
- Los efectos de dosificación genética indicaron que KEX2 es el gen estructural para esta endopeptidasa.
Conclusiones:
- El gen KEX2 codifica una endopeptidasa asociada a la membrana esencial para el procesamiento adecuado de los péptidos secretados en S. cerevisiae.
- Esta actividad de la endopeptidasa es crítica para la función biológica de péptidos como el factor alfa.
- El producto del gen KEX2 juega un papel vital en la vía secretora de la levadura.
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