PMID- 34408020
OWN - NLM
STAT- MEDLINE
DCOM- 20211213
LR  - 20220219
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 118
IP  - 34
DP  - 2021 Aug 24
TI  - Cooperative recruitment of RDR6 by SGS3 and SDE5 during small interfering RNA 
      amplification in Arabidopsis.
LID - 10.1073/pnas.2102885118 [doi]
LID - e2102885118
AB  - Small interfering RNAs (siRNAs) are often amplified from transcripts cleaved by 
      RNA-induced silencing complexes (RISCs) containing a small RNA (sRNA) and an 
      Argonaute protein. Amplified siRNAs, termed secondary siRNAs, are important for 
      reinforcement of target repression. In plants, target cleavage by RISCs 
      containing 22-nucleotide (nt) sRNA and Argonaute 1 (AGO1) triggers siRNA 
      amplification. In this pathway, the cleavage fragment is converted into 
      double-stranded RNA (dsRNA) by RNA-dependent RNA polymerase 6 (RDR6), and the 
      dsRNA is processed into siRNAs by Dicer-like proteins. Because nonspecific RDR6 
      recruitment causes nontarget siRNA production, it is critical that RDR6 is 
      specifically recruited to the target RNA that serves as a template for dsRNA 
      formation. Previous studies showed that Suppressor of Gene Silencing 3 (SGS3) 
      binds and stabilizes 22-nt sRNA-containing AGO1 RISCs associated with cleaved 
      target, but how RDR6 is recruited to targets cleaved by 22-nt sRNA-containing 
      AGO1 RISCs remains unknown. Here, using cell-free extracts prepared from 
      suspension-cultured Arabidopsis thaliana cells, we established an in vitro system 
      for secondary siRNA production in which 22-nt siRNA-containing AGO1-RISCs but not 
      21-nt siRNA-containing AGO1-RISCs induce secondary siRNA production. In this 
      system, addition of recombinant Silencing Defective 5 (SDE5) protein remarkably 
      enhances secondary siRNA production. We show that RDR6 is recruited to a cleavage 
      fragment by 22-nt siRNA-containing AGO1-RISCs in coordination with SGS3 and SDE5. 
      The SGS3-SDE5-RDR6 multicomponent recognition system and the poly(A) tail 
      inhibition may contribute to securing specificity of siRNA amplification.
FAU - Yoshikawa, Manabu
AU  - Yoshikawa M
AUID- ORCID: 0000-0001-6574-2038
AD  - Institute of Agrobiological Sciences, National Agriculture and Food Research 
      Organization, Tsukuba, Ibaraki 305-8518, Japan; myoshika@affrc.go.jp.
FAU - Han, Yong-Woon
AU  - Han YW
AUID- ORCID: 0000-0001-6169-1659
AD  - Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical 
      Sciences, Yokohama 230-0045, Japan.
FAU - Fujii, Hirofumi
AU  - Fujii H
AUID- ORCID: 0000-0002-2375-4775
AD  - Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, 
      Tokyo 125-8585, Japan.
FAU - Aizawa, Shu
AU  - Aizawa S
AD  - Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, 
      Tokyo 125-8585, Japan.
FAU - Nishino, Tatsuya
AU  - Nishino T
AUID- ORCID: 0000-0001-8017-8762
AD  - Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, 
      Tokyo 125-8585, Japan.
FAU - Ishikawa, Masayuki
AU  - Ishikawa M
AUID- ORCID: 0000-0002-0301-2715
AD  - Institute of Agrobiological Sciences, National Agriculture and Food Research 
      Organization, Tsukuba, Ibaraki 305-8518, Japan.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Arabidopsis Proteins)
RN  - 0 (RNA, Double-Stranded)
RN  - 0 (RNA, Small Interfering)
RN  - 0 (RNA-Induced Silencing Complex)
RN  - 0 (SDE5 protein, Arabidopsis)
RN  - 0 (SGS3 protein, Arabidopsis)
RN  - EC 2.7.7.48 (RDR6 protein, Arabidopsis)
RN  - EC 2.7.7.48 (RNA-Dependent RNA Polymerase)
SB  - IM
CIN - doi: 10.1073/pnas.2102889118
MH  - Arabidopsis/*genetics/metabolism
MH  - Arabidopsis Proteins/genetics/*metabolism
MH  - Gene Expression Regulation, Plant
MH  - RNA, Double-Stranded/genetics/*metabolism
MH  - RNA, Small Interfering/genetics/*metabolism
MH  - RNA-Dependent RNA Polymerase/genetics/*metabolism
MH  - RNA-Induced Silencing Complex/genetics/*metabolism
PMC - PMC8403909
OTO - NOTNLM
OT  - Argonaute
OT  - RNA silencing
OT  - RNA-dependent RNA polymerase
OT  - secondary siRNA
OT  - siRNA
COIS- The authors declare no competing interest.
EDAT- 2021/08/20 06:00
MHDA- 2021/12/15 06:00
PMCR- 2022/02/18
CRDT- 2021/08/19 05:55
PHST- 2021/08/19 05:55 [entrez]
PHST- 2021/08/20 06:00 [pubmed]
PHST- 2021/12/15 06:00 [medline]
PHST- 2022/02/18 00:00 [pmc-release]
AID - 2102885118 [pii]
AID - 202102885 [pii]
AID - 10.1073/pnas.2102885118 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 2021 Aug 24;118(34):e2102885118. doi: 
      10.1073/pnas.2102885118.