PMID- 23542151
OWN - NLM
STAT- MEDLINE
DCOM- 20131224
LR  - 20211021
IS  - 1532-2548 (Electronic)
IS  - 0032-0889 (Print)
IS  - 0032-0889 (Linking)
VI  - 162
IP  - 1
DP  - 2013 May
TI  - The initiation of epigenetic silencing of active transposable elements is 
      triggered by RDR6 and 21-22 nucleotide small interfering RNAs.
PG  - 116-31
LID - 10.1104/pp.113.216481 [doi]
AB  - Transposable elements (TEs) are mobile fragments of DNA that are repressed in 
      both plant and animal genomes through the epigenetic inheritance of repressed 
      chromatin and expression states. The epigenetic silencing of TEs in plants is 
      mediated by a process of RNA-directed DNA methylation (RdDM). Two pathways of 
      RdDM have been identified: RNA Polymerase IV (Pol IV)-RdDM, which has been shown 
      to be responsible for the de novo initiation, corrective reestablishment, and 
      epigenetic maintenance of TE and/or transgene silencing; and RNA-dependent RNA 
      Polymerase6 (RDR6)-RdDM, which was recently identified as necessary for 
      maintaining repression for a few TEs. We have further characterized RDR6-RdDM 
      using a genome-wide search to identify TEs that generate RDR6-dependent small 
      interfering RNAs. We have determined that TEs only produce RDR6-dependent small 
      interfering RNAs when transcriptionally active, and we have experimentally 
      identified two TE subfamilies as direct targets of RDR6-RdDM. We used these TEs 
      to test the function of RDR6-RdDM in assays for the de novo initiation, 
      corrective reestablishment, and maintenance of TE silencing. We found that 
      RDR6-RdDM plays no role in maintaining TE silencing. Rather, we found that RDR6 
      and Pol IV are two independent entry points into RdDM and epigenetic silencing 
      that perform distinct functions in the silencing of TEs: Pol IV-RdDM functions to 
      maintain TE silencing and to initiate silencing in an RNA Polymerase II 
      expression-independent manner, while RDR6-RdDM functions to recognize active 
      Polymerase II-derived TE mRNA transcripts to both trigger and correctively 
      reestablish TE methylation and epigenetic silencing.
FAU - Nuthikattu, Saivageethi
AU  - Nuthikattu S
AD  - Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 
      43210, USA.
FAU - McCue, Andrea D
AU  - McCue AD
FAU - Panda, Kaushik
AU  - Panda K
FAU - Fultz, Dalen
AU  - Fultz D
FAU - DeFraia, Christopher
AU  - DeFraia C
FAU - Thomas, Erica N
AU  - Thomas EN
FAU - Slotkin, R Keith
AU  - Slotkin RK
LA  - eng
GR  - T32 GM086252/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20130329
PL  - United States
TA  - Plant Physiol
JT  - Plant physiology
JID - 0401224
RN  - 0 (Arabidopsis Proteins)
RN  - 0 (DNA Transposable Elements)
RN  - 0 (RNA, Plant)
RN  - 0 (RNA, Small Interfering)
RN  - EC 2.7.7.- (RNA Polymerase II)
RN  - EC 2.7.7.- (RNA polymerase IV, Arabidopsis)
RN  - EC 2.7.7.48 (RDR6 protein, Arabidopsis)
RN  - EC 2.7.7.48 (RNA-Dependent RNA Polymerase)
RN  - EC 2.7.7.6 (DNA-Directed RNA Polymerases)
SB  - IM
MH  - Arabidopsis/*genetics/metabolism
MH  - Arabidopsis Proteins/*genetics/metabolism
MH  - DNA Methylation
MH  - DNA Transposable Elements/genetics
MH  - DNA-Directed RNA Polymerases/genetics/metabolism
MH  - *Epigenesis, Genetic
MH  - Gene Expression Profiling
MH  - *Gene Expression Regulation, Plant
MH  - Gene Library
MH  - Gene Silencing
MH  - Genome, Plant/genetics
MH  - Mutation
MH  - Oligonucleotide Array Sequence Analysis
MH  - Plants, Genetically Modified
MH  - RNA Polymerase II/genetics/metabolism
MH  - RNA, Plant/genetics/metabolism
MH  - RNA, Small Interfering/*genetics/metabolism
MH  - RNA-Dependent RNA Polymerase/*genetics/metabolism
MH  - Sequence Analysis, DNA
MH  - Transgenes
PMC - PMC3641197
EDAT- 2013/04/02 06:00
MHDA- 2013/12/25 06:00
PMCR- 2013/03/29
CRDT- 2013/04/02 06:00
PHST- 2013/04/02 06:00 [entrez]
PHST- 2013/04/02 06:00 [pubmed]
PHST- 2013/12/25 06:00 [medline]
PHST- 2013/03/29 00:00 [pmc-release]
AID - pp.113.216481 [pii]
AID - 216481 [pii]
AID - 10.1104/pp.113.216481 [doi]
PST - ppublish
SO  - Plant Physiol. 2013 May;162(1):116-31. doi: 10.1104/pp.113.216481. Epub 2013 Mar 
      29.