title: RNA-directed DNA methylation in plants: Where to start?
abstract: Plants use 24-nucleotide small interfering RNAs (24-nt siRNAs) and long non-coding RNAs (lncRNAs) to direct de novo DNA methylation and transcriptional gene silencing. This process is called RNA-directed DNA methylation (RdDM). An important question in the RdDM model is what explains the target specificity of RNA polymerase IV (Pol IV), the enzyme that initiates siRNA production. Two recent papers addressed this question by characterizing the DTF1/SHH1 protein, which contains a homeodomain in the N-terminus and a novel histone-binding domain SAWADEE in the C terminus. Here we review the main results of the two studies and discuss several possible mechanisms that could contribute to Pol IV and Pol V recruitment.
authors.affiliation: Shanghai Center for Plant Stress Biology; Shanghai Institute of Biological Sciences; Chinese Academy of Sciences; Shanghai, P.R. China.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: National Institute of Biological Sciences; Beijing, P.R. China.
authors.forename: Xinjian
authors.initials: X
authors.lastname: He
authors.affiliation: Shanghai Center for Plant Stress Biology; Shanghai Institute of Biological Sciences; Chinese Academy of Sciences; Shanghai, P.R. China; Department of Horticulture and Landscape Architecture; Purdue University; West Lafayette, IN USA.
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000378:metabolism; D019175:DNA Methylation; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018749:RNA, Plant / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018749:RNA, Plant; D034741:RNA, Small Interfering; C499181:RNA polymerase IV, Arabidopsis; C538841:RNA polymerase V, Arabidopsis; D012321:DNA-Directed RNA Polymerases
keywords: DNA methylation; RdDM; histone modification; lncRNA; siRNA