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La glutamina sintetasa de Bacillus subtilis controla la expresión génica a través de una interacción
L V Wray1, J M Zalieckas, S H Fisher
1Department of Microbiology, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA.
Cell
|November 24, 2001
Resumen
La glutamina sintetasa regula directamente el TnrA de Bacillus subtilis, que es un factor de transcripción global. La enzima inhibida por la retroalimentación bloquea el TnrAA.
Área de la Ciencia:
- Microbiología Microbiología.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- Bacillus subtilis TnrA es un regulador de la transcripción global que responde a la disponibilidad de nitrógeno.
- La molécula de señal precisa que regula la actividad de TnrA no ha sido identificada.
- Estudios genéticos previos implicaron a la glutamina sintetasa en la regulación de la TnrA in vivo.
Objetivo del estudio:
- Para identificar la interacción directa entre la glutamina sintetasa y el TnrA.
- Para dilucidar el mecanismo por el cual la glutamina sintetasa regula la actividad de unión al ADN de TnrA.
- Para caracterizar las mutaciones en TnrA que afectan a su regulación por la glutamina sintetasa.
Principales métodos:
- Pruebas de unión al ADN in vitro para evaluar la interacción del TnrA con el ADN.
- Caracterización de las mutaciones de TnrA (tnrA(C)) que confieren expresión génica constitutiva.
- Análisis del efecto de la sintetasa de glutamina inhibida por retroalimentación en la unión de TnrA al ADN.
Principales resultados:
- La glutamina sintetasa inhibida por retroalimentación se une directamente al TnrA.
- Esta interacción inhibe la actividad de unión al ADN de TnrA.
- Las proteínas TnrA mutantes (TnrA(C)) mostraron una inhibición reducida por la sintetasa de glutamina inhibida por retroalimentación.
Conclusiones:
- La glutamina sintetasa actúa como un regulador directo del factor de transcripción global TnrA.
- La interacción involucra la forma inhibida de retroalimentación de la glutamina sintetasa que bloquea la unión al ADN del TnrA.
- Este estudio revela un nuevo mecanismo regulador que vincula el metabolismo central con el control de la transcripción en Bacillus subtilis.
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