Plant-specific multisubunit RNA polymerase in gene silencing.
Résumé
In recent years, a major breakthrough in the study of epigenetic silencing in eukaryotes came with the discovery that the RNA-interference pathway (RNAi) is generally implicated in heterochromatin assembly and gene silencing. An important and paradoxical feature of the RNAi-mediated heterochromatin pathways is their requirement for some form of transcription. In fission yeast, Schizosaccharomyces pombe, centromeric siRNAs have been shown to derive from chromatin-bound nascent transcripts produced by RNA polymerase II (PolII) at the site of heterochromatin formation. Likewise, chromatin-bound nascent transcripts generated by a PolII-related DNA-dependent RNA polymerase, known as PolIVb/PolV, have recently been implicated in RNA-directed DNA methylation (RdDM), the prominent RNAi-mediated chromatin pathway in plants. In this review we discuss recent work on the plant-specific PolII variant enzymes and discuss the mechanistic convergences that have been observed in the role of these enzymes in their respective siRNA-mediated heterochromatin formation pathways.
Domaines
- Biochimie, Biologie Moléculaire
- Biochimie [q-bio.BM]
- Amélioration des plantes
- Génétique
- Génétique des plantes
- Evolution [q-bio.PE]
- Systématique, phylogénie et taxonomie
- 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]
- Bio-informatique [q-bio.QM]
- Biologie végétale