A Role for RNAi in the Selective Correction of DNA Methylation Defects

Felipe Karam Teixeira (1, 2) , Fabiana Heredia (1) , Alexis Sarazin (2) , François Roudier (1, 2) , Martine Boccara (1, 2) , Constance Ciaudo (3, 4) , Corinne Cruaud (5) , Julie Poulain (5) , María Berdasco (6) , Mario F. Fraga (6) , Olivier Voinnet (3) , Patrick Wincker (5) , Manel Esteller (6) , Vincent Colot (1, 2)

1 URGV - Unité de recherche en génomique végétale
2 Biologie moléculaire des organismes photosynthétiques (UMR8186)
3 IBMP - Institut de Biologie Moléculaire des Plantes
4 DNPG - Dynamique nucléaire et plasticité du génome
5 GENOSCOPE - Genoscope - Centre national de séquençage [Evry]
6 CNIO - Centro Nacional de Investigaciones Oncologicas / Spanish National Cancer Research Centre [Madrid, Espagne]

DNA methylation is essential for silencing transposable elements and some genes in higher eukaryotes, which suggests that this modification must be tightly controlled. However, accidental changes in DNA methylation can be transmitted through mitosis (as in cancer) or meiosis, leading to epiallelic variation. We demonstrated the existence of an efficient mechanism that protects against transgenerational loss of DNA methylation in Arabidopsis. Remethylation is specific to the subset of heavily methylated repeats that are targeted by the RNA interference (RNAi) machinery. This process does not spread into flanking regions, is usually progressive over several generations, and faithfully restores wild-type methylation over target sequences in an RNAi-dependent manner. Our findings suggest an important role for RNAi in protecting genomes against long-term epigenetic defects.

Domaines: Sciences du Vivant [q-bio]

Felipe Karam Teixeira, Fabiana Heredia, Alexis Sarazin, François Roudier, Martine Boccara, et al.. A Role for RNAi in the Selective Correction of DNA Methylation Defects. Science, 2009, 323 (5921), pp.1600-1604. ⟨10.1126/science.1165313⟩. ⟨cea-00817409⟩