title: DNA topoisomerase 1α promotes transcriptional silencing of transposable elements through DNA methylation and histone lysine 9 dimethylation in Arabidopsis.
abstract: RNA-directed DNA methylation (RdDM) and histone H3 lysine 9 dimethylation (H3K9me2) are related transcriptional silencing mechanisms that target transposable elements (TEs) and repeats to maintain genome stability in plants. RdDM is mediated by small and long noncoding RNAs produced by the plant-specific RNA polymerases Pol IV and Pol V, respectively. Through a chemical genetics screen with a luciferase-based DNA methylation reporter, LUCL, we found that camptothecin, a compound with anti-cancer properties that targets DNA topoisomerase 1α (TOP1α) was able to de-repress LUCL by reducing its DNA methylation and H3K9me2 levels. Further studies with Arabidopsis top1α mutants showed that TOP1α silences endogenous RdDM loci by facilitating the production of Pol V-dependent long non-coding RNAs, AGONAUTE4 recruitment and H3K9me2 deposition at TEs and repeats. This study assigned a new role in epigenetic silencing to an enzyme that affects DNA topology.
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America; ChemGen IGERT program, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Thanh Theresa
authors.initials: TT
authors.lastname: Dinh
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Lei
authors.initials: L
authors.lastname: Gao
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Xigang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America; School of Life Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Dongming
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Shengben
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Leary
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Brandon
authors.initials: B
authors.lastname: Le
authors.affiliation: Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schmitz
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Manavella
authors.affiliation: Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Pablo
authors.initials: P
authors.lastname: Manavella
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Shaofang
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Detlef
authors.initials: D
authors.lastname: Weigel
authors.affiliation: Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America.
authors.forename: Olga
authors.initials: O
authors.lastname: Pontes
authors.affiliation: Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America; Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California, United States of America.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ecker
authors.affiliation: Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, United States of America; Howard Hughes Medical Institute, University of California Riverside, Riverside, California, United States of America.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Chen
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D004264:DNA Topoisomerases, Type I / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements / Q000235:genetics*; D044127:Epigenesis, Genetic; D020868:Gene Silencing; D006657:Histones / Q000235:genetics; D008239:Lysine / Q000235:genetics; D009154:Mutation; D012313:RNA / Q000235:genetics; D062085:RNA, Long Noncoding / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D004251:DNA Transposable Elements; D006657:Histones; D062085:RNA, Long Noncoding; D012313:RNA; D004264:DNA Topoisomerases, Type I; D008239:Lysine