title: Argonaute slicing is required for heterochromatic silencing and spreading.
abstract: Small interfering RNA (siRNA) guides dimethylation of histone H3 lysine-9 (H3K9me2) via the Argonaute and RNA-dependent RNA polymerase complexes, as well as base-pairing with either RNA or DNA. We show that Argonaute requires the conserved aspartate-aspartate-histidine motif for heterochromatic silencing and for ribonuclease H-like cleavage (slicing) of target messages complementary to siRNA. In the fission yeast Schizosaccharomyces pombe, heterochromatic repeats are transcribed by polymerase II. We show that H3K9me2 spreads into silent reporter genes when they are embedded within these transcripts and that spreading requires read-through transcription, as well as slicing by Argonaute. Thus, siRNA guides histone modification by basepairing interactions with RNA.
authors.affiliation: Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
authors.forename: Danielle V
authors.initials: DV
authors.lastname: Irvine
authors.forename: Mikel
authors.initials: M
authors.lastname: Zaratiegui
authors.forename: Niraj H
authors.initials: NH
authors.lastname: Tolia
authors.forename: Derek B
authors.initials: DB
authors.lastname: Goto
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Chitwood
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Vaughn
authors.forename: Leemor
authors.initials: L
authors.lastname: Joshua-Tor
authors.forename: Robert A
authors.initials: RA
authors.lastname: Martienssen
mesh_terms: D020816:Amino Acid Motifs; D060565:Argonaute Proteins; D020029:Base Pairing; D017930:Genes, Reporter; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D034622:RNA Interference; D012331:RNA, Fungal / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C481643:Ago1 protein, S pombe; D060565:Argonaute Proteins; D006570:Heterochromatin; D006657:Histones; D012331:RNA, Fungal; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C400810:ura4 protein, S pombe