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El papel de los elementos transponibles en la heterocromatina y el control epigenético
Zachary Lippman1, Anne-Valérie Gendrel, Michael Black
1Watson School of Biological Sciences and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
Nature
|July 23, 2004
Resumen
La heterocromatina en Arabidopsis se compone principalmente de elementos transponibles y repeticiones, reguladas por el DDM1. Es probable que los pequeños ARN interferentes (siARN) guíen este proceso, influyendo en la expresión génica.
Área de la Ciencia:
- Genética La genética.
- La epigenética es la epigenética.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La heterocromatina, caracterizada por el material cromosómico condensado, se encuentra cerca de los centrómeros y los telómeros.
- La heterocromatina intersticial (botones) es común en los genomas de las plantas, especialmente en el maíz, y es repetitiva y de replicación tardía.
- El papel de la heterocromatina en la expresión génica, ejemplificado por la variación del efecto de posición en Drosophila, sugiere una función reguladora.
Objetivo del estudio:
- Para investigar la composición y regulación de la heterocromatina en Arabidopsis.
- Explorar el papel de los elementos transponibles y los pequeños ARN interferentes (siARN) en la formación de la heterocromatina y la regulación génica.
- Comprender la regulación epigenética de los genes por elementos transponibles y los factores asociados de remodelación de la cromatina.
Principales métodos:
- Análisis de microarrays para identificar secuencias heterocromáticas.
- Análisis de pequeños ARN interferentes (siARN) correspondientes a regiones heterocromáticas.
- Investigando la regulación epigenética del gen impreso FWA.
Principales resultados:
- La heterocromatina de Arabidopsis está determinada por elementos transponibles y repeticiones en tándem, controladas por la ATPasa DDM1 que remodela la cromatina (disminución de la metilación del ADN 1).
- A estas secuencias heterocromáticas corresponden pequeños ARN interferentes (siRNA), lo que sugiere un papel en la orientación del DDM1.
- Los elementos transponibles pueden regular epigenéticamente los genes cuando se insertan dentro o cerca de ellos, lo que explica la regulación DDM1 y MET1 del gen impreso FWA.
Conclusiones:
- La heterocromatina en Arabidopsis está compuesta en gran parte de elementos y repeticiones transponibles, regulados por DDM1 y guiados por siRNAs.
- Los elementos transponibles juegan un papel importante en la regulación epigenética de los genes, particularmente cuando se encuentran cerca de los promotores de genes.
- El estudio aclara los mecanismos moleculares subyacentes a la formación de la heterocromatina y su impacto en la expresión génica y el desarrollo en las plantas.
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