InterPro domain: IPR044567

This entry represents a group of SNF2 domain-containing proteins from plants, including CLSY1-3 and DRD1 from Arabidopsis. CLSY and DRD1 contain a SNF2-like domain and a helicase domain near the C terminus. They are required for siRNA-directed DNA methylation in Arabidopsis [ 1 , 2 ]. Polymerases IVa/Pol IV and Pol IVb/Pol V are plant-specific RNA polymerases involved in in multiple small RNA-mediated gene silencing pathways. CLSY1 is required for proper localization of both NRPD1 (the largest subunit of Pol IV) and RDR2 [ 3 ]. DRD1 has been shown to mediate RNA polymerases IV and V (Pol IV and Pol V) recruitment to chromatin [ 3 , 4 ]. Interestingly, DRD1 and Pol V appear to be required not only for RNA-directed de novo methylation, but also for full erasure of methylation when the RNA trigger is withdrawn [ 5 ].

1. Identification of genes required for de novo DNA methylation in Arabidopsis. Epigenetics 6, 344-54
2. Involvement of putative SNF2 chromatin remodeling protein DRD1 in RNA-directed DNA methylation. Curr Biol 14, 801-5
3. Noncoding transcription by RNA polymerase Pol IVb/Pol V mediates transcriptional silencing of overlapping and adjacent genes. Cell 135, 635-48
4. DDR complex facilitates global association of RNA polymerase V to promoters and evolutionarily young transposons. Nat Struct Mol Biol 19, 870-5
5. RNA-directed DNA methylation mediated by DRD1 and Pol IVb: a versatile pathway for transcriptional gene silencing in plants. Biochim Biophys Acta 1769, 358-74