title: Involvement of a GHKL ATPase in RNA-directed DNA methylation in Arabidopsis thaliana.
abstract: RNA-directed DNA methylation (RdDM) is a small interfering RNA (siRNA)-mediated epigenetic modification that contributes to transposon silencing in plants. RdDM requires a complex transcriptional machinery comprising two RNA polymerase II-related RNA polymerases, called Pol IV and Pol V, as well as chromatin remodelers, transcription factors, and other novel proteins whose roles in the RdDM mechanism remain poorly understood. We have identified a new component of the RdDM machinery, DMS11 (defective in meristem silencing 11), which has a GHKL (gyrase, Hsp90, histidine kinase, MutL) ATPase domain. siRNAs accumulate in the dms11 mutant, and repressive epigenetic modifications undergo only modest reductions at target sequences. DMS11 interacts physically with another RdDM component, DMS3, an unusual structural maintenance of chromosomes (SMC) hinge domain-containing protein that lacks the ATPase motifs of authentic SMC proteins. The hinge region of DMS3 resembles that of the mammalian epigenetic factor SMCHD1, which also has a GHKL-type ATPase. In vitro, DMS11 has ATPase activity that is stimulated by DMS3. We suggest that DMS11 provides the missing ATPase function for DMS3 and that these proteins cooperate in the RdDM pathway to promote transcriptional repression. GHKL ATPases are thus emerging as new players in epigenetic regulation in plants and mammals.
authors.affiliation: Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna, Austria.
authors.forename: Zdravko J
authors.initials: ZJ
authors.lastname: Lorković
authors.forename: Ulf
authors.initials: U
authors.lastname: Naumann
authors.forename: Antonius J M
authors.initials: AJ
authors.lastname: Matzke
authors.forename: Marjori
authors.initials: M
authors.lastname: Matzke
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D018506:Gene Expression Regulation, Plant; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; C529025:DMS3 protein, Arabidopsis; D034741:RNA, Small Interfering; D000251:Adenosine Triphosphatases; C573243:MORC6 protein, Arabidopsis