PMID- 22049083
OWN - NLM
STAT- MEDLINE
DCOM- 20120227
LR  - 20240507
IS  - 1083-351X (Electronic)
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 286
IP  - 52
DP  - 2011 Dec 30
TI  - Nucleus-localized antisense small RNAs with 5'-polyphosphate termini regulate 
      long term transcriptional gene silencing in Entamoeba histolytica G3 strain.
PG  - 44467-79
LID - 10.1074/jbc.M111.278184 [doi]
AB  - In the deep-branching eukaryotic parasite Entamoeba histolytica, transcriptional 
      gene silencing (TGS) of the Amoebapore A gene (ap-a) in the G3 strain has been 
      reported with subsequent development of this parasite strain for gene silencing. 
      However, the mechanisms underlying this gene silencing approach are poorly 
      understood. Here we report that antisense small RNAs (sRNAs) specific to the 
      silenced ap-a gene can be identified in G3 parasites. Furthermore, when 
      additional genes are silenced in the G3 strain, antisense sRNAs to the newly 
      silenced genes can also be detected. Characterization of these sRNAs demonstrates 
      that they are ~27 nucleotides in size, have 5'-polyphosphate termini, and persist 
      even after removal of the silencing plasmid. Immunofluorescence analysis (IFA) 
      and fluorescence in situ hybridization (FISH) show that both the Argonaute 
      protein EhAGO2-2 and antisense sRNAs to the silenced genes are localized to the 
      parasite nucleus. Furthermore, alpha-EhAGO2-2 immunoprecipitation confirmed the 
      direct association of the antisense sRNAs with EhAGO2-2. Finally, chromatin 
      immunoprecipitation (ChIP) assays demonstrate that the loci of the silenced genes 
      are enriched for histone H3 and EhAGO2-2, indicating that both chromatin 
      modification and the RNA-induced transcriptional silencing complex are involved 
      in permanent gene silencing in G3 parasites. In conclusion, our data demonstrate 
      that G3-based gene silencing in E. histolytica is mediated by an siRNA pathway, 
      which utilizes antisense 5'-polyphosphate sRNAs. To our knowledge, this is the 
      first study to show that 5'- polyphosphate antisense sRNAs can mediate TGS, and 
      it is the first example of RNAi-mediated TGS in protozoan parasites.
FAU - Zhang, Hanbang
AU  - Zhang H
AD  - Division of Infectious Diseases, Department of Internal Medicine, Stanford 
      University School of Medicine, Stanford, California 94305-5107, USA.
FAU - Alramini, Hussein
AU  - Alramini H
FAU - Tran, Vy
AU  - Tran V
FAU - Singh, Upinder
AU  - Singh U
LA  - eng
GR  - R01 AI053724/AI/NIAID NIH HHS/United States
GR  - R21 AI085178/AI/NIAID NIH HHS/United States
GR  - AI-085178/AI/NIAID NIH HHS/United States
GR  - AI-053724/AI/NIAID NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20111102
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Polyphosphates)
RN  - 0 (RNA, Protozoan)
RN  - 0 (RNA, Small Interfering)
SB  - IM
MH  - Cell Nucleus/genetics/*metabolism
MH  - Entamoeba histolytica/genetics/*metabolism
MH  - Gene Silencing/*physiology
MH  - Polyphosphates/*metabolism
MH  - RNA, Protozoan/genetics/*metabolism
MH  - RNA, Small Interfering/genetics/*metabolism
MH  - Transcription, Genetic/*physiology
PMC - PMC3247957
EDAT- 2011/11/04 06:00
MHDA- 2012/03/01 06:00
PMCR- 2012/12/30
CRDT- 2011/11/04 06:00
PHST- 2011/11/04 06:00 [entrez]
PHST- 2011/11/04 06:00 [pubmed]
PHST- 2012/03/01 06:00 [medline]
PHST- 2012/12/30 00:00 [pmc-release]
AID - S0021-9258(20)65498-9 [pii]
AID - M111.278184 [pii]
AID - 10.1074/jbc.M111.278184 [doi]
PST - ppublish
SO  - J Biol Chem. 2011 Dec 30;286(52):44467-79. doi: 10.1074/jbc.M111.278184. Epub 
      2011 Nov 2.