Stochastic silencing phenotype of Arabidopsis morc6 mutants reveals a role in efficient RNA-directed DNA methylation

TY - JOUR

T1 - Stochastic silencing phenotype of Arabidopsis morc6 mutants reveals a role in efficient RNA-directed DNA methylation

AU - Brabbs, Thomas R

AU - He, Zhesi

AU - Hogg, Karen

AU - Kamenski, Andrei

AU - Li, Yi

AU - Paszkiewicz, Konrad H

AU - Moore, Karen A

AU - O'Toole, Peter John

AU - Graham, Ian A

AU - Jones, Louise

N1 - This article is protected by copyright. All rights reserved.

PY - 2013/5/16

Y1 - 2013/5/16

N2 - The RNA-directed DNA methylation (RdDM) pathway is of central importance to the initiation and maintenance of transcriptional gene silencing in plants. DNA methylation is directed to target sequences in a mechanism that involves the production of small RNAs by RNA Polymerase IV and by long non-coding RNAs by RNA Polymerase V. DNA methylation then leads to the recruitment of histone modifying enzymes followed by the establishment of a silenced chromatin state. Recently MORC6, a member of the Microrchidia (MORC) family of adenosine triphosphatases (ATPases), has been shown to be involved in transcriptional gene silencing. However reports differed regarding whether MORC6 was involved in RdDM itself or acting downstream of DNA methylation to enable the formation of higher order chromatin structure. In this work we demonstrate that MORC6 is required for efficient RdDM at some target loci and using a GFP reporter system we observe that morc6 mutants give rise to a stochastic silencing phenotype. By using cell sorting to separate silenced and unsilenced cells, we show that release of silencing at this locus does not occur in the absence of a loss of DNA methylation. Thus our data supports a view that MORC6 can influence RdDM and that it is not only acting downstream of DNA methylation. Therefore for some loci, efficient initiation or maintenance of DNA methylation may depend on the ability to form higher order chromatin structure. This article is protected by copyright. All rights reserved.

AB - The RNA-directed DNA methylation (RdDM) pathway is of central importance to the initiation and maintenance of transcriptional gene silencing in plants. DNA methylation is directed to target sequences in a mechanism that involves the production of small RNAs by RNA Polymerase IV and by long non-coding RNAs by RNA Polymerase V. DNA methylation then leads to the recruitment of histone modifying enzymes followed by the establishment of a silenced chromatin state. Recently MORC6, a member of the Microrchidia (MORC) family of adenosine triphosphatases (ATPases), has been shown to be involved in transcriptional gene silencing. However reports differed regarding whether MORC6 was involved in RdDM itself or acting downstream of DNA methylation to enable the formation of higher order chromatin structure. In this work we demonstrate that MORC6 is required for efficient RdDM at some target loci and using a GFP reporter system we observe that morc6 mutants give rise to a stochastic silencing phenotype. By using cell sorting to separate silenced and unsilenced cells, we show that release of silencing at this locus does not occur in the absence of a loss of DNA methylation. Thus our data supports a view that MORC6 can influence RdDM and that it is not only acting downstream of DNA methylation. Therefore for some loci, efficient initiation or maintenance of DNA methylation may depend on the ability to form higher order chromatin structure. This article is protected by copyright. All rights reserved.

U2 - 10.1111/tpj.12246

DO - 10.1111/tpj.12246

M3 - Article

C2 - 23675613

SN - 1365-313X

VL - Early View

SP - n/a

JO - The Plant journal

JF - The Plant journal

IS - n/a

ER -