title: The splicing machinery promotes RNA-directed DNA methylation and transcriptional silencing in Arabidopsis.
abstract: DNA methylation in transposons and other DNA repeats is conserved in plants as well as in animals. In Arabidopsis thaliana, an RNA-directed DNA methylation (RdDM) pathway directs de novo DNA methylation. We performed a forward genetic screen for suppressors of the DNA demethylase mutant ros1 and identified a novel Zinc-finger and OCRE domain-containing Protein 1 (ZOP1) that promotes Pol IV-dependent siRNA accumulation, DNA methylation, and transcriptional silencing. Whole-genome methods disclosed the genome-wide effects of zop1 on Pol IV-dependent siRNA accumulation and DNA methylation, suggesting that ZOP1 has both RdDM-dependent and -independent roles in transcriptional silencing. We demonstrated that ZOP1 is a pre-mRNA splicing factor that associates with several typical components of the splicing machinery as well as with Pol II. Immunofluorescence assay revealed that ZOP1 overlaps with Cajal body and is partially colocalized with NRPE1 and DRM2. Moreover, we found that the other development-defective splicing mutants tested including mac3a3b, mos4, mos12 and mos14 show defects in RdDM and transcriptional silencing. We propose that the splicing machinery rather than specific splicing factors is involved in promoting RdDM and transcriptional silencing.
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Cui-Jun
authors.initials: CJ
authors.lastname: Zhang
authors.forename: Jin-Xing
authors.initials: JX
authors.lastname: Zhou
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Ze-Yang
authors.initials: ZY
authors.lastname: Ma
authors.forename: Su-Wei
authors.initials: SW
authors.lastname: Zhang
authors.forename: Kun
authors.initials: K
authors.lastname: Dou
authors.forename: Huan-Wei
authors.initials: HW
authors.lastname: Huang
authors.forename: Tao
authors.initials: T
authors.lastname: Cai
authors.forename: Renyi
authors.initials: R
authors.lastname: Liu
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
authors.forename: Xin-Jian
authors.initials: XJ
authors.lastname: He
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D019175:DNA Methylation; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D005786:Gene Expression Regulation; D012313:RNA / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism; D012326:RNA Splicing; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D012313:RNA; D004247:DNA; D012319:RNA Polymerase II; C499181:RNA polymerase IV, Arabidopsis; D012321:DNA-Directed RNA Polymerases