title: An atypical component of RNA-directed DNA methylation machinery has both DNA methylation-dependent and -independent roles in locus-specific transcriptional gene silencing.
abstract: RNA-directed DNA methylation (RdDM) is an important de novo DNA methylation pathway in plants. RdDM mediates the transcriptional silencing of many endogenous genomic loci, most of which are transposon related. A forward genetics screen identified DTF1 (DNA-binding transcription factor 1) as a new component for RdDM in Arabidopsis. Loss-of-function mutations in DTF1 release the transcriptional silencing of RdDM target loci and reduce the accumulation of 24-nt small interfering RNAs (siRNAs) from some of the targets. Interestingly, in the dtf1 mutant plants, the release of transcriptional gene silencing at solo-LTR is accompanied by decreased siRNA accumulation but not by reduced DNA methylation. These results suggest that DTF1 is an atypical component of RdDM and has both DNA methylation-dependent and -independent roles in transcriptional gene silencing. We suggest that besides DNA methylation, siRNAs may cause some other uncharacterized epigenetic modifications that lead to transcriptional gene silencing.
authors: National Institute of Biological Sciences, Beijing 102206, China.
authors: Jun
authors: J
authors: Liu
authors: Ge
authors: G
authors: Bai
authors: Cuijun
authors: C
authors: Zhang
authors: Wei
authors: W
authors: Chen
authors: Jinxing
authors: J
authors: Zhou
authors: Suwei
authors: S
authors: Zhang
authors: Qing
authors: Q
authors: Chen
authors: Xin
authors: X
authors: Deng
authors: Xin-Jian
authors: XJ
authors: He
authors: Jian-Kang
authors: JK
authors: Zhu
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation; D020868:Gene Silencing; D056426:Genetic Loci; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; C520629:RD29a protein, Arabidopsis; D034741:RNA, Small Interfering