An RNA polymerase II- and AGO4-associated protein acts in RNA-directed DNA methylation.
Résumé
DNA methylation is an important epigenetic mark in many eukaryotes. In plants, 24-nucleotide small interfering RNAs (siRNAs) bound to the effector protein, Argonaute 4 (AGO4), can direct de novo DNA methylation by the methyltransferase DRM2 (refs 2, 4-6). Here we report a new regulator of RNA-directed DNA methylation (RdDM) in Arabidopsis: RDM1. Loss-of-function mutations in the RDM1 gene impair the accumulation of 24-nucleotide siRNAs, reduce DNA methylation, and release transcriptional gene silencing at RdDM target loci. RDM1 encodes a small protein that seems to bind single-stranded methyl DNA, and associates and co-localizes with RNA polymerase II (Pol II, also known as NRPB), AGO4 and DRM2 in the nucleus. Our results indicate that RDM1 is a component of the RdDM effector complex and may have a role in linking siRNA production with pre-existing or de novo cytosine methylation. Our results also indicate that, although RDM1 and Pol V (also known as NRPE) may function together at some RdDM target sites in the peri-nucleolar siRNA processing centre, Pol II rather than Pol V is associated with the RdDM effector complex at target sites in the nucleoplasm.
Domaines
Biochimie, Biologie Moléculaire Bio-informatique [q-bio.QM] Systématique, phylogénie et taxonomie Biologie végétale Amélioration des plantes Génétique Génétique des plantes Biochimie [q-bio.BM] Biologie moléculaire Biologie structurale [q-bio.BM] Génomique, Transcriptomique et Protéomique [q-bio.GN] Réseaux moléculaires [q-bio.MN] Biologie cellulaire Bio-Informatique, Biologie Systémique [q-bio.QM] Evolution [q-bio.PE]Origine | Fichiers produits par l'(les) auteur(s) |
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