title: MORC family ATPases required for heterochromatin condensation and gene silencing.
abstract: Transposable elements (TEs) and DNA repeats are commonly targeted by DNA and histone methylation to achieve epigenetic gene silencing. We isolated mutations in two Arabidopsis genes, AtMORC1 and AtMORC6, which cause derepression of DNA-methylated genes and TEs but no losses of DNA or histone methylation. AtMORC1 and AtMORC6 are members of the conserved Microrchidia (MORC) adenosine triphosphatase (ATPase) family, which are predicted to catalyze alterations in chromosome superstructure. The atmorc1 and atmorc6 mutants show decondensation of pericentromeric heterochromatin, increased interaction of pericentromeric regions with the rest of the genome, and transcriptional defects that are largely restricted to loci residing in pericentromeric regions. Knockdown of the single MORC homolog in Caenorhabditis elegans also impairs transgene silencing. We propose that the MORC ATPases are conserved regulators of gene silencing in eukaryotes.
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Terasaki Life Sciences Building, 610 Charles Young Drive East, Los Angeles, CA 90095-723905, USA.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Moissiard
authors.forename: Shawn J
authors.initials: SJ
authors.lastname: Cokus
authors.forename: Joshua
authors.initials: J
authors.lastname: Cary
authors.forename: Suhua
authors.initials: S
authors.lastname: Feng
authors.forename: Allison C
authors.initials: AC
authors.lastname: Billi
authors.forename: Hume
authors.initials: H
authors.lastname: Stroud
authors.forename: Dylan
authors.initials: D
authors.lastname: Husmann
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhan
authors.forename: Bryan R
authors.initials: BR
authors.lastname: Lajoie
authors.forename: Rachel Patton
authors.initials: RP
authors.lastname: McCord
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hale
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.forename: Scott D
authors.initials: SD
authors.lastname: Michaels
authors.forename: Alison R
authors.initials: AR
authors.lastname: Frand
authors.forename: Matteo
authors.initials: M
authors.lastname: Pellegrini
authors.forename: Job
authors.initials: J
authors.lastname: Dekker
authors.forename: John K
authors.initials: JK
authors.lastname: Kim
authors.forename: Steven E
authors.initials: SE
authors.lastname: Jacobsen
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002503:Centromere; D019175:DNA Methylation; D004251:DNA Transposable Elements; D020868:Gene Silencing; D017343:Genes, Plant; D006570:Heterochromatin / Q000378:metabolism* / Q000648:ultrastructure; D006657:Histones / Q000378:metabolism; D008745:Methylation; D009154:Mutation; D034741:RNA, Small Interfering / Q000378:metabolism; D014158:Transcription, Genetic; D019076:Transgenes; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D029742:Caenorhabditis elegans Proteins; D004251:DNA Transposable Elements; D006570:Heterochromatin; D006657:Histones; D034741:RNA, Small Interfering; D000251:Adenosine Triphosphatases; C573242:MORC1 protein, Arabidopsis; C573243:MORC6 protein, Arabidopsis