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Las compensaciones y la optimización en la evolución de la regulación génica
Frank J Poelwijk1, Marjon G J de Vos, Sander J Tans
1AMOLF Institute, Science Park 104, 1098 XG Amsterdam, The Netherlands.
Cell
|August 2, 2011
Resumen
La regulación celular evoluciona para optimizar las respuestas en entornos variables. Un estudio sobre el lacrepresor (LacI) en E. coli reveló una adaptación hacia una estrategia reguladora óptima, superando las limitaciones evolutivas.
Área de la Ciencia:
- Biología evolutiva Biología evolutiva.
- Biología molecular La biología molecular.
- Biología de sistemas Biología de sistemas.
Sus antecedentes:
- Se supone que la regulación celular se adapta a los cambios ambientales.
- Las pruebas experimentales directas de esta hipótesis han sido desafiantes.
- Comprender la evolución reguladora es clave para predecir la adaptación de los organismos.
Objetivo del estudio:
- Para probar experimentalmente si la regulación génica desarrolla respuestas óptimas a la variabilidad ambiental.
- Investigar la dinámica evolutiva y las limitaciones de un sistema regulador genético específico.
- Para vincular la optimización de compensación teórica a las observaciones empíricas de la evolución regulatoria.
Principales métodos:
- Diseñó un módulo genético en E. coli regulado por el lacrepresor (LacI).
- Sometido el sistema diseñado a entornos donde la expresión de LacI es condicionalmente beneficiosa o perjudicial.
- Se midieron las compensaciones de la aptitud física y se analizaron las trayectorias evolutivas y las mutaciones en LacI.
Principales resultados:
- El sistema de regulación génica evolucionó hacia una respuesta reguladora óptima bajo condiciones ambientales variables.
- La adaptación evolutiva se retrasó inicialmente debido a las limitaciones en los límites regulatorios específicos de LacI.
- El alivio de estas restricciones por mutación condujo a la adaptación, lo que resultó en LacI con un mecanismo alostérico alterado.
- El LacI evolucionado exhibió una respuesta opuesta a su ligando regulador, IPTG.
Conclusiones:
- La evolución de la regulación puede entenderse a través de la lente de la teoría de optimización de compensación.
- La variabilidad ambiental impulsa la evolución de las estrategias regulatorias óptimas.
- Las restricciones moleculares específicas pueden influir en el ritmo y la dirección de la evolución reguladora.
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