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Regulación de la actividad del ARN mensajero jun-B y AP-1 por la luz y un reloj circadiano
J M Kornhauser1, D E Nelson, K E Mayo
1Institute for Neuroscience, Northwestern University, Evanston, IL 60208.
Science (New York, N.Y.)
|March 20, 1992
Resumen
La luz sincroniza el reloj circadiano de los mamíferos en los núcleos supraquiasmáticos (SCN). Este proceso involucra genes inmediatos y tempranos como jun-B, cruciales para el arrastre circadiano.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Cronobiología cronobiología.
- Biología Molecular Biología Molecular
Sus antecedentes:
- Los núcleos supraquiasmáticos (SCN) en el hipotálamo actúan como el marcapasos circadiano maestro en los mamíferos.
- Los ritmos circadianos son sincronizados (atraídos) por señales externas, principalmente la luz.
- Los genes inmediatamente tempranos, como el c-fos, se expresan rápidamente en respuesta a estímulos como la luz, lo que sugiere un papel en la plasticidad neuronal y la señalización.
Objetivo del estudio:
- Investigar el papel de la expresión génica inmediata y temprana en el SCN durante el arrastre de la luz circadiana.
- Para determinar si la expresión génica inducida por la luz en el SCN es dependiente de fase y está vinculada a los cambios de ritmo conductual.
Principales métodos:
- Medición de los niveles de ARN mensajero (ARNm) de c-fos, c-jun y jun-B en el SCN de roedores y hámsters dorados después de la exposición a la luz.
- Evaluación de la actividad de unión del complejo del factor de transcripción AP-1 en la SCN.
- Correlación de la expresión génica y la actividad de unión de AP-1 con la fase circadiana y la aparición de cambios de ritmo conductual.
Principales resultados:
- Los estímulos luminosos inducen la expresión del gen c-fos en el SCN, implicando a Fos en el arrastre circadiano.
- La estimulación fótica regula específicamente la actividad de unión de jun-B mRNA y AP-1 al ADN en el SCN, con un efecto mínimo en c-jun.
- La inducción de jun-B mRNA y la unión de AP-1 es dependiente de fase, y ocurre solo cuando los estímulos de luz cambian los ritmos de comportamiento.
Conclusiones:
- La luz y el marcapasos circadiano del SCN interactúan para regular genes específicos inmediatos y tempranos.
- La regulación fótica de la actividad de jun-B y AP-1 en el SCN es un mecanismo clave potencialmente involucrado en el arrastre de los ritmos circadianos.
- Estos hallazgos ponen de relieve las vías moleculares a través de las cuales la información luminosa se procesa dentro de la SCN para ajustar los relojes biológicos internos.
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